feat: expand vehicle data platform capabilities

2026-07-27 16:46:15 +08:00
parent e3a1f80f86
commit 3c4bece72c
650 changed files with 62155 additions and 2552 deletions
--- a/go/vehicle-gateway/cmd/legacy-mileage-migrate/main.go
+++ b/go/vehicle-gateway/cmd/legacy-mileage-migrate/main.go
@@ -0,0 +1,743 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"encoding/json"
+	"errors"
+	"flag"
+	"fmt"
+	"math"
+	"os"
+	"regexp"
+	"sort"
+	"strings"
+	"time"
+
+	mysql "github.com/go-sql-driver/mysql"
+)
+
+const (
+	protocol           = "GB32960"
+	legacySourceIP     = "legacy-mysql.lingniu-prod"
+	legacySourceKey    = "GB32960:LEGACY_MILEAGE@legacy-mysql.lingniu-prod"
+	legacySourceCode   = "legacy_lingniu_prod"
+	legacyPlatformName = "历史生产库里程"
+	legacyQuality      = "legacy_mysql_backfill_before_2026-07-21"
+	maxDailyMileageKM  = 2500.0
+)
+
+var vinPattern = regexp.MustCompile(`^[A-HJ-NPR-Z0-9]{17}$`)
+
+type sourceRecord struct {
+	ID            int64
+	Identifier    string
+	StatDate      time.Time
+	DailyKM       sql.NullFloat64
+	TotalKM       sql.NullFloat64
+	Now           sql.NullTime
+	MappingOrigin string
+	VIN           string
+}
+
+type mappingIndex struct {
+	Unique    map[string]string
+	Ambiguous map[string]struct{}
+}
+
+type scanReport struct {
+	SourceRows                   int      `json:"source_rows"`
+	SourceDistinctIdentifiers    int      `json:"source_distinct_identifiers"`
+	DedupedSourceRows            int      `json:"deduped_source_rows"`
+	DuplicateRows                int      `json:"duplicate_rows"`
+	ConflictingDuplicateGroups   int      `json:"conflicting_duplicate_groups"`
+	MappedByCurrentVehicle       int      `json:"mapped_by_current_vehicle"`
+	MappedByLegacyVehicle        int      `json:"mapped_by_legacy_vehicle"`
+	CurrentLegacyVINConflicts    int      `json:"current_legacy_vin_conflicts"`
+	UnresolvedRows               int      `json:"unresolved_rows"`
+	UnresolvedIdentifiers        int      `json:"unresolved_identifiers"`
+	UnresolvedEligibleRows       int      `json:"unresolved_eligible_rows"`
+	UnresolvedIdentifierValues   []string `json:"unresolved_identifier_values,omitempty"`
+	NullMileageRows              int      `json:"null_mileage_rows"`
+	ZeroMileageRows              int      `json:"zero_mileage_rows"`
+	NegativeMileageRows          int      `json:"negative_mileage_rows"`
+	OverLimitMileageRows         int      `json:"over_limit_mileage_rows"`
+	EligibleRows                 int      `json:"eligible_rows"`
+	VINDateCollisions            int      `json:"vin_date_collisions"`
+	ConflictingVINDateCollisions int      `json:"conflicting_vin_date_collisions"`
+}
+
+type targetReport struct {
+	StageRows                         int64   `json:"stage_rows"`
+	MissingRows                       int64   `json:"missing_rows"`
+	ZeroRows                          int64   `json:"zero_rows"`
+	NonzeroProtectedRows              int64   `json:"nonzero_protected_rows"`
+	ExistingPositiveCandidateRows     int64   `json:"existing_positive_candidate_rows"`
+	ProtectedSameMileageRows          int64   `json:"protected_same_mileage_rows"`
+	ProtectedMileageSumKM             float64 `json:"protected_mileage_sum_km"`
+	ProtectedMileageFingerprint       uint64  `json:"protected_mileage_fingerprint"`
+	LegacyCandidateRows               int64   `json:"legacy_candidate_rows"`
+	LegacyCandidateTotalMatchedRows   int64   `json:"legacy_candidate_total_matched_rows"`
+	LegacyProjectedRows               int64   `json:"legacy_projected_rows"`
+	LegacyProjectedTotalMatchedRows   int64   `json:"legacy_projected_total_matched_rows"`
+	LegacySelectedCandidateRows       int64   `json:"legacy_selected_candidate_rows"`
+	PreexistingNonLegacyRows          int64   `json:"preexisting_non_legacy_rows"`
+	PreexistingNonLegacyMileageSumKM  float64 `json:"preexisting_non_legacy_mileage_sum_km"`
+	PreexistingNonLegacyFingerprint   uint64  `json:"preexisting_non_legacy_fingerprint"`
+	RemainingMissingOrZeroRows        int64   `json:"remaining_missing_or_zero_rows"`
+	PostProtectedRows                 int64   `json:"post_protected_rows"`
+	PostProtectedMileageSumKM         float64 `json:"post_protected_mileage_sum_km"`
+	PostProtectedMileageFingerprint   uint64  `json:"post_protected_mileage_fingerprint"`
+	ProtectedRowsUnchanged            int64   `json:"protected_rows_unchanged"`
+	ProtectedMileageFingerprintStable bool    `json:"protected_mileage_fingerprint_stable"`
+}
+
+type output struct {
+	Mode                string       `json:"mode"`
+	CutoffExclusive     string       `json:"cutoff_exclusive"`
+	Protocol            string       `json:"protocol"`
+	SourceTable         string       `json:"source_table"`
+	TotalMileageDivisor float64      `json:"total_mileage_divisor_m_to_km"`
+	Scan                scanReport   `json:"scan"`
+	Target              targetReport `json:"target"`
+	Duration            string       `json:"duration"`
+}
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}
+
+func run() error {
+	var cutoffRaw, dsn string
+	var apply bool
+	var timeout time.Duration
+	flag.StringVar(&cutoffRaw, "before", "2026-07-21", "exclusive upper date boundary (YYYY-MM-DD)")
+	flag.StringVar(&dsn, "mysql-dsn", strings.TrimSpace(os.Getenv("MYSQL_DSN")), "target MySQL DSN")
+	flag.BoolVar(&apply, "apply", false, "apply the migration; default is dry-run")
+	flag.DurationVar(&timeout, "timeout", 10*time.Minute, "overall timeout")
+	flag.Parse()
+
+	started := time.Now()
+	cutoff, err := time.ParseInLocation("2006-01-02", strings.TrimSpace(cutoffRaw), time.FixedZone("Asia/Shanghai", 8*3600))
+	if err != nil {
+		return fmt.Errorf("invalid -before date: %w", err)
+	}
+	if strings.TrimSpace(dsn) == "" {
+		return errors.New("MYSQL_DSN or -mysql-dsn is required")
+	}
+	dsn, err = normalizedDSN(dsn)
+	if err != nil {
+		return err
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), timeout)
+	defer cancel()
+	db, err := sql.Open("mysql", dsn)
+	if err != nil {
+		return err
+	}
+	defer db.Close()
+	db.SetMaxOpenConns(2)
+	if err := db.PingContext(ctx); err != nil {
+		return err
+	}
+
+	conn, err := db.Conn(ctx)
+	if err != nil {
+		return err
+	}
+	defer conn.Close()
+	currentMappings, err := loadMappingIndex(ctx, conn, `
+SELECT CONVERT(plate USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM vehicle
+WHERE plate IS NOT NULL AND TRIM(plate) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM vehicle_identifier
+WHERE enabled = 1 AND plate IS NOT NULL AND TRIM(plate) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''`)
+	if err != nil {
+		return fmt.Errorf("load current vehicle mappings: %w", err)
+	}
+	legacyMappings, err := loadMappingIndex(ctx, conn, `
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.tab_truck
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.truck_info
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.v_vehicle_daily_stats
+WHERE plate IS NOT NULL AND TRIM(plate) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.tab_truck_remote_sync_realtime_info
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.view_truck_comprehensive_info
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin_code USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.tab_hecri_hydrogen_order
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin_code IS NOT NULL AND TRIM(vin_code) <> ''
+UNION ALL
+SELECT CONVERT(plate USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.bi_ele_charge_record
+WHERE plate IS NOT NULL AND TRIM(plate) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.v_truck_task_basic
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''
+UNION ALL
+SELECT CONVERT(plate_number USING utf8mb4) COLLATE utf8mb4_unicode_ci AS plate,
+       CONVERT(vin USING utf8mb4) COLLATE utf8mb4_unicode_ci AS vin FROM lingniu_prod.view_vehicle_annual_inspection
+WHERE plate_number IS NOT NULL AND TRIM(plate_number) <> '' AND vin IS NOT NULL AND TRIM(vin) <> ''`)
+	if err != nil {
+		return fmt.Errorf("load legacy vehicle mappings: %w", err)
+	}
+	records, report, err := loadAndResolveSource(ctx, conn, cutoff, currentMappings, legacyMappings)
+	if err != nil {
+		return err
+	}
+	if err := createAndLoadStage(ctx, conn, records); err != nil {
+		return err
+	}
+	target, err := inspectTarget(ctx, conn)
+	if err != nil {
+		return err
+	}
+
+	mode := "dry_run"
+	if apply {
+		mode = "apply"
+		if err := createProtectedSnapshot(ctx, conn); err != nil {
+			return err
+		}
+		if err := applyMigration(ctx, conn); err != nil {
+			return err
+		}
+		post, err := inspectTarget(ctx, conn)
+		if err != nil {
+			return err
+		}
+		post.PostProtectedRows, post.PostProtectedMileageSumKM, post.PostProtectedMileageFingerprint, post.ProtectedRowsUnchanged, err = inspectProtectedSnapshot(ctx, conn)
+		if err != nil {
+			return err
+		}
+		post.ProtectedMileageFingerprintStable =
+			target.PreexistingNonLegacyRows == post.PostProtectedRows &&
+				math.Abs(target.PreexistingNonLegacyMileageSumKM-post.PostProtectedMileageSumKM) < 0.0005 &&
+				target.PreexistingNonLegacyFingerprint == post.PostProtectedMileageFingerprint &&
+				post.ProtectedRowsUnchanged == target.PreexistingNonLegacyRows
+		post.NonzeroProtectedRows = target.NonzeroProtectedRows
+		post.ProtectedSameMileageRows = target.ProtectedSameMileageRows
+		post.ProtectedMileageSumKM = target.ProtectedMileageSumKM
+		post.ProtectedMileageFingerprint = target.ProtectedMileageFingerprint
+		target = post
+	}
+
+	result := output{
+		Mode: mode, CutoffExclusive: cutoff.Format("2006-01-02"), Protocol: protocol,
+		SourceTable: "lingniu_prod.ln_vehicle_day_mileage", TotalMileageDivisor: 1000, Scan: report, Target: target,
+		Duration: time.Since(started).Round(time.Millisecond).String(),
+	}
+	encoder := json.NewEncoder(os.Stdout)
+	encoder.SetIndent("", "  ")
+	return encoder.Encode(result)
+}
+
+func createProtectedSnapshot(ctx context.Context, conn *sql.Conn) error {
+	_, err := conn.ExecContext(ctx, `
+CREATE TEMPORARY TABLE tmp_legacy_mileage_protected AS
+SELECT m.vin, m.stat_date, m.protocol, m.source_id, m.daily_mileage_km,
+       m.latest_total_mileage_km, m.updated_at
+FROM tmp_legacy_mileage_stage st
+JOIN vehicle_daily_mileage m
+  ON m.vin = st.vin AND m.stat_date = st.stat_date AND m.protocol = 'GB32960'
+LEFT JOIN vehicle_data_source ds ON ds.id = m.source_id
+WHERE m.daily_mileage_km > 0 AND COALESCE(ds.source_ip, '') <> ?`, legacySourceIP)
+	if err != nil {
+		return fmt.Errorf("snapshot protected mileage rows: %w", err)
+	}
+	return nil
+}
+
+func inspectProtectedSnapshot(ctx context.Context, queryer interface {
+	QueryRowContext(context.Context, string, ...any) *sql.Row
+}) (count int64, sum float64, fingerprint uint64, unchanged int64, err error) {
+	var nullableSum sql.NullFloat64
+	err = queryer.QueryRowContext(ctx, `
+SELECT
+  COUNT(m.vin),
+  SUM(CASE WHEN m.vin IS NOT NULL THEN m.daily_mileage_km ELSE 0 END),
+  COALESCE(BIT_XOR(CASE WHEN m.vin IS NOT NULL THEN CRC32(CONCAT_WS('|', m.vin, m.stat_date, m.protocol, m.daily_mileage_km, COALESCE(m.latest_total_mileage_km, 'NULL'))) ELSE 0 END), 0),
+  COALESCE(SUM(
+    m.vin IS NOT NULL
+    AND (m.source_id <=> p.source_id)
+    AND (m.daily_mileage_km <=> p.daily_mileage_km)
+    AND (m.latest_total_mileage_km <=> p.latest_total_mileage_km)
+    AND (m.updated_at <=> p.updated_at)
+  ), 0)
+FROM tmp_legacy_mileage_protected p
+LEFT JOIN vehicle_daily_mileage m
+  ON m.vin = p.vin AND m.stat_date = p.stat_date AND m.protocol = p.protocol`).Scan(
+		&count, &nullableSum, &fingerprint, &unchanged,
+	)
+	if err != nil {
+		return 0, 0, 0, 0, fmt.Errorf("verify protected mileage snapshot: %w", err)
+	}
+	if nullableSum.Valid {
+		sum = nullableSum.Float64
+	}
+	return count, sum, fingerprint, unchanged, nil
+}
+
+func normalizedDSN(raw string) (string, error) {
+	cfg, err := mysql.ParseDSN(strings.TrimSpace(raw))
+	if err != nil {
+		return "", fmt.Errorf("parse mysql dsn: %w", err)
+	}
+	cfg.ParseTime = true
+	cfg.Loc = time.FixedZone("Asia/Shanghai", 8*3600)
+	cfg.Params = cloneMap(cfg.Params)
+	cfg.Params["charset"] = "utf8mb4"
+	return cfg.FormatDSN(), nil
+}
+
+func cloneMap(source map[string]string) map[string]string {
+	result := make(map[string]string, len(source)+1)
+	for key, value := range source {
+		result[key] = value
+	}
+	return result
+}
+
+func loadMappingIndex(ctx context.Context, queryer interface {
+	QueryContext(context.Context, string, ...any) (*sql.Rows, error)
+}, query string) (mappingIndex, error) {
+	rows, err := queryer.QueryContext(ctx, query)
+	if err != nil {
+		return mappingIndex{}, err
+	}
+	defer rows.Close()
+	values := map[string]map[string]struct{}{}
+	for rows.Next() {
+		var plate, vin sql.NullString
+		if err := rows.Scan(&plate, &vin); err != nil {
+			return mappingIndex{}, err
+		}
+		plateValue := normalizeIdentifier(plate.String)
+		vinValue := normalizeVIN(vin.String)
+		if plateValue == "" || !vinPattern.MatchString(vinValue) {
+			continue
+		}
+		if values[plateValue] == nil {
+			values[plateValue] = map[string]struct{}{}
+		}
+		values[plateValue][vinValue] = struct{}{}
+	}
+	if err := rows.Err(); err != nil {
+		return mappingIndex{}, err
+	}
+	result := mappingIndex{Unique: map[string]string{}, Ambiguous: map[string]struct{}{}}
+	for plate, vins := range values {
+		if len(vins) != 1 {
+			result.Ambiguous[plate] = struct{}{}
+			continue
+		}
+		for vin := range vins {
+			result.Unique[plate] = vin
+		}
+	}
+	return result, nil
+}
+
+func loadAndResolveSource(ctx context.Context, queryer interface {
+	QueryContext(context.Context, string, ...any) (*sql.Rows, error)
+}, cutoff time.Time, current, legacy mappingIndex) ([]sourceRecord, scanReport, error) {
+	rows, err := queryer.QueryContext(ctx, `
+SELECT id, plateNumber, dates, dayMileage, totalMileage, nowDatetime
+FROM lingniu_prod.ln_vehicle_day_mileage
+WHERE dates < ?
+ORDER BY plateNumber, dates, (nowDatetime IS NULL), nowDatetime DESC, id DESC`, cutoff)
+	if err != nil {
+		return nil, scanReport{}, fmt.Errorf("query source mileage: %w", err)
+	}
+	defer rows.Close()
+
+	var report scanReport
+	distinctIdentifiers := map[string]struct{}{}
+	unresolvedIdentifiers := map[string]struct{}{}
+	byIdentifierDate := map[string]sourceRecord{}
+	duplicateValues := map[string]float64{}
+	conflictingDuplicateKeys := map[string]struct{}{}
+	for rows.Next() {
+		var item sourceRecord
+		var rawIdentifier sql.NullString
+		if err := rows.Scan(&item.ID, &rawIdentifier, &item.StatDate, &item.DailyKM, &item.TotalKM, &item.Now); err != nil {
+			return nil, report, err
+		}
+		report.SourceRows++
+		item.Identifier = normalizeIdentifier(rawIdentifier.String)
+		distinctIdentifiers[item.Identifier] = struct{}{}
+		key := item.Identifier + "\x00" + item.StatDate.Format("2006-01-02")
+		if existing, ok := byIdentifierDate[key]; ok {
+			report.DuplicateRows++
+			if item.DailyKM.Valid && existing.DailyKM.Valid && math.Abs(item.DailyKM.Float64-existing.DailyKM.Float64) > 0.0005 {
+				conflictingDuplicateKeys[key] = struct{}{}
+			}
+			continue
+		}
+		byIdentifierDate[key] = item
+		if item.DailyKM.Valid {
+			duplicateValues[key] = item.DailyKM.Float64
+		}
+	}
+	if err := rows.Err(); err != nil {
+		return nil, report, err
+	}
+	_ = duplicateValues
+	report.SourceDistinctIdentifiers = len(distinctIdentifiers)
+	report.DedupedSourceRows = len(byIdentifierDate)
+	report.ConflictingDuplicateGroups = len(conflictingDuplicateKeys)
+
+	keys := make([]string, 0, len(byIdentifierDate))
+	for key := range byIdentifierDate {
+		keys = append(keys, key)
+	}
+	sort.Strings(keys)
+	stageByVINDate := map[string]sourceRecord{}
+	var stageOrder []string
+	for _, key := range keys {
+		item := byIdentifierDate[key]
+		vin, origin, conflict := resolveVIN(item.Identifier, current, legacy)
+		if conflict {
+			report.CurrentLegacyVINConflicts++
+		}
+		if vin == "" {
+			report.UnresolvedRows++
+			unresolvedIdentifiers[item.Identifier] = struct{}{}
+			if item.DailyKM.Valid && item.DailyKM.Float64 > 0 && item.DailyKM.Float64 <= maxDailyMileageKM {
+				report.UnresolvedEligibleRows++
+			}
+			continue
+		}
+		item.VIN = vin
+		item.MappingOrigin = origin
+		if origin == "current_vehicle" {
+			report.MappedByCurrentVehicle++
+		} else {
+			report.MappedByLegacyVehicle++
+		}
+		if !item.DailyKM.Valid {
+			report.NullMileageRows++
+			continue
+		}
+		switch {
+		case item.DailyKM.Float64 == 0:
+			report.ZeroMileageRows++
+			continue
+		case item.DailyKM.Float64 < 0:
+			report.NegativeMileageRows++
+			continue
+		case item.DailyKM.Float64 > maxDailyMileageKM:
+			report.OverLimitMileageRows++
+			continue
+		}
+		report.EligibleRows++
+		stageKey := item.VIN + "\x00" + item.StatDate.Format("2006-01-02")
+		if existing, ok := stageByVINDate[stageKey]; ok {
+			report.VINDateCollisions++
+			if math.Abs(existing.DailyKM.Float64-item.DailyKM.Float64) > 0.0005 {
+				report.ConflictingVINDateCollisions++
+			}
+			if item.ID <= existing.ID {
+				continue
+			}
+		} else {
+			stageOrder = append(stageOrder, stageKey)
+		}
+		stageByVINDate[stageKey] = item
+	}
+	report.UnresolvedIdentifiers = len(unresolvedIdentifiers)
+	for identifier := range unresolvedIdentifiers {
+		report.UnresolvedIdentifierValues = append(report.UnresolvedIdentifierValues, identifier)
+	}
+	sort.Strings(report.UnresolvedIdentifierValues)
+	sort.Strings(stageOrder)
+	stage := make([]sourceRecord, 0, len(stageOrder))
+	for _, key := range stageOrder {
+		stage = append(stage, stageByVINDate[key])
+	}
+	return stage, report, nil
+}
+
+func resolveVIN(identifier string, current, legacy mappingIndex) (vin, origin string, conflict bool) {
+	if vinPattern.MatchString(identifier) {
+		return identifier, "source_vin", false
+	}
+	currentVIN, currentOK := current.Unique[identifier]
+	legacyVIN, legacyOK := legacy.Unique[identifier]
+	if currentOK && legacyOK && currentVIN != legacyVIN {
+		return "", "", true
+	}
+	if currentOK {
+		return currentVIN, "current_vehicle", false
+	}
+	if legacyOK {
+		return legacyVIN, "legacy_vehicle", false
+	}
+	return "", "", false
+}
+
+func normalizeIdentifier(value string) string {
+	return strings.ToUpper(strings.Join(strings.Fields(strings.TrimSpace(value)), ""))
+}
+
+func normalizeVIN(value string) string {
+	return strings.ToUpper(strings.TrimSpace(value))
+}
+
+func createAndLoadStage(ctx context.Context, conn *sql.Conn, records []sourceRecord) error {
+	if _, err := conn.ExecContext(ctx, `
+CREATE TEMPORARY TABLE tmp_legacy_mileage_stage (
+  vin VARCHAR(32) NOT NULL,
+  stat_date DATE NOT NULL,
+  daily_mileage_km DECIMAL(18,3) NOT NULL,
+  total_mileage_km DECIMAL(18,3) NULL,
+  source_record_id BIGINT NOT NULL,
+  mapping_origin VARCHAR(32) NOT NULL,
+  PRIMARY KEY (vin, stat_date)
+) ENGINE=InnoDB`); err != nil {
+		return fmt.Errorf("create temporary stage: %w", err)
+	}
+	const batchSize = 500
+	for start := 0; start < len(records); start += batchSize {
+		end := min(start+batchSize, len(records))
+		var query strings.Builder
+		query.WriteString("INSERT INTO tmp_legacy_mileage_stage (vin, stat_date, daily_mileage_km, total_mileage_km, source_record_id, mapping_origin) VALUES ")
+		args := make([]any, 0, (end-start)*6)
+		for index, item := range records[start:end] {
+			if index > 0 {
+				query.WriteByte(',')
+			}
+			query.WriteString("(?,?,?,?,?,?)")
+			args = append(args, item.VIN, item.StatDate, item.DailyKM.Float64, nullableTotalMileageKM(item.TotalKM), item.ID, item.MappingOrigin)
+		}
+		if _, err := conn.ExecContext(ctx, query.String(), args...); err != nil {
+			return fmt.Errorf("load temporary stage batch %d: %w", start/batchSize+1, err)
+		}
+	}
+	return nil
+}
+
+func nullableTotalMileageKM(value sql.NullFloat64) any {
+	if !value.Valid {
+		return nil
+	}
+	return value.Float64 / 1000
+}
+
+func inspectTarget(ctx context.Context, queryer interface {
+	QueryRowContext(context.Context, string, ...any) *sql.Row
+}) (targetReport, error) {
+	var report targetReport
+	var protectedSum sql.NullFloat64
+	err := queryer.QueryRowContext(ctx, `
+SELECT
+  COUNT(*),
+  COALESCE(SUM(m.vin IS NULL), 0),
+  COALESCE(SUM(m.vin IS NOT NULL AND m.daily_mileage_km = 0), 0),
+  COALESCE(SUM(m.daily_mileage_km > 0), 0),
+  COALESCE(SUM(m.daily_mileage_km > 0 AND ABS(m.daily_mileage_km - st.daily_mileage_km) <= 0.011), 0),
+  SUM(CASE WHEN m.daily_mileage_km > 0 THEN m.daily_mileage_km ELSE 0 END),
+  COALESCE(BIT_XOR(CASE WHEN m.daily_mileage_km > 0 THEN CRC32(CONCAT_WS('|', m.vin, m.stat_date, m.protocol, m.daily_mileage_km, COALESCE(m.latest_total_mileage_km, 'NULL'))) ELSE 0 END), 0),
+  COALESCE(SUM(candidate.vin IS NOT NULL AND (m.vin IS NULL OR m.daily_mileage_km = 0)), 0)
+FROM tmp_legacy_mileage_stage st
+LEFT JOIN vehicle_daily_mileage m
+  ON m.vin = st.vin AND m.stat_date = st.stat_date AND m.protocol = 'GB32960'
+LEFT JOIN (
+  SELECT vin, stat_date
+  FROM vehicle_daily_mileage_source
+  WHERE protocol = 'GB32960' AND quality_status = 'OK' AND daily_mileage_km > 0
+  GROUP BY vin, stat_date
+) candidate ON candidate.vin = st.vin AND candidate.stat_date = st.stat_date`).Scan(
+		&report.StageRows, &report.MissingRows, &report.ZeroRows, &report.NonzeroProtectedRows,
+		&report.ProtectedSameMileageRows, &protectedSum, &report.ProtectedMileageFingerprint,
+		&report.ExistingPositiveCandidateRows,
+	)
+	if err != nil {
+		return report, fmt.Errorf("inspect migration target: %w", err)
+	}
+	if protectedSum.Valid {
+		report.ProtectedMileageSumKM = protectedSum.Float64
+	}
+	if err := queryer.QueryRowContext(ctx, `
+SELECT COUNT(*), COALESCE(SUM(s.latest_total_mileage_km <=> st.total_mileage_km), 0)
+FROM vehicle_daily_mileage_source s
+JOIN tmp_legacy_mileage_stage st ON st.vin = s.vin AND st.stat_date = s.stat_date
+WHERE s.protocol = 'GB32960' AND s.source_key = ?`, legacySourceKey).Scan(
+		&report.LegacyCandidateRows, &report.LegacyCandidateTotalMatchedRows,
+	); err != nil {
+		return report, err
+	}
+	if err := queryer.QueryRowContext(ctx, `
+SELECT COUNT(*)
+FROM vehicle_daily_mileage_source s
+JOIN tmp_legacy_mileage_stage st ON st.vin = s.vin AND st.stat_date = s.stat_date
+WHERE s.protocol = 'GB32960' AND s.source_key = ? AND s.is_selected = 1`, legacySourceKey).Scan(&report.LegacySelectedCandidateRows); err != nil {
+		return report, err
+	}
+	if err := queryer.QueryRowContext(ctx, `
+SELECT COUNT(*), COALESCE(SUM(m.latest_total_mileage_km <=> st.total_mileage_km), 0)
+FROM vehicle_daily_mileage m
+JOIN tmp_legacy_mileage_stage st ON st.vin = m.vin AND st.stat_date = m.stat_date
+JOIN vehicle_data_source ds ON ds.id = m.source_id
+WHERE m.protocol = 'GB32960' AND ds.protocol = 'GB32960' AND ds.source_ip = ?
+  AND ABS(m.daily_mileage_km - st.daily_mileage_km) <= 0.0005`, legacySourceIP).Scan(
+		&report.LegacyProjectedRows, &report.LegacyProjectedTotalMatchedRows,
+	); err != nil {
+		return report, err
+	}
+	if err := queryer.QueryRowContext(ctx, `
+SELECT COUNT(*)
+FROM tmp_legacy_mileage_stage st
+LEFT JOIN vehicle_daily_mileage m
+  ON m.vin = st.vin AND m.stat_date = st.stat_date AND m.protocol = 'GB32960'
+WHERE m.vin IS NULL OR m.daily_mileage_km = 0`).Scan(&report.RemainingMissingOrZeroRows); err != nil {
+		return report, err
+	}
+	var nonLegacySum sql.NullFloat64
+	if err := queryer.QueryRowContext(ctx, `
+SELECT
+  COUNT(*),
+  SUM(m.daily_mileage_km),
+  COALESCE(BIT_XOR(CRC32(CONCAT_WS('|', m.vin, m.stat_date, m.protocol, m.daily_mileage_km, COALESCE(m.latest_total_mileage_km, 'NULL')))), 0)
+FROM vehicle_daily_mileage m
+JOIN tmp_legacy_mileage_stage st ON st.vin = m.vin AND st.stat_date = m.stat_date
+LEFT JOIN vehicle_data_source ds ON ds.id = m.source_id
+WHERE m.protocol = 'GB32960' AND m.daily_mileage_km > 0
+  AND COALESCE(ds.source_ip, '') <> ?`, legacySourceIP).Scan(
+		&report.PreexistingNonLegacyRows, &nonLegacySum, &report.PreexistingNonLegacyFingerprint,
+	); err != nil {
+		return report, err
+	}
+	if nonLegacySum.Valid {
+		report.PreexistingNonLegacyMileageSumKM = nonLegacySum.Float64
+	}
+	return report, nil
+}
+
+func applyMigration(ctx context.Context, conn *sql.Conn) error {
+	tx, err := conn.BeginTx(ctx, &sql.TxOptions{Isolation: sql.LevelReadCommitted})
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+	if _, err := tx.ExecContext(ctx, `
+INSERT INTO vehicle_data_source
+  (protocol, source_ip, latest_source_endpoint, platform_name, source_code, source_kind,
+   trust_priority, enabled, first_seen_at, latest_seen_at, remark)
+VALUES ('GB32960', ?, 'lingniu_prod.ln_vehicle_day_mileage', ?, ?, 'UNKNOWN', 1000, 1,
+        '2024-10-17 00:00:00', '2026-07-20 23:59:59',
+        '仅用于迁移 2026-07-21 之前缺失或为 0 的 GB32960 日里程')
+ON DUPLICATE KEY UPDATE
+  latest_source_endpoint = VALUES(latest_source_endpoint),
+  platform_name = VALUES(platform_name),
+  source_code = VALUES(source_code),
+  source_kind = VALUES(source_kind),
+  trust_priority = VALUES(trust_priority),
+  enabled = 1,
+  remark = VALUES(remark)`, legacySourceIP, legacyPlatformName, legacySourceCode); err != nil {
+		return fmt.Errorf("upsert legacy data source: %w", err)
+	}
+	var sourceID int64
+	if err := tx.QueryRowContext(ctx, `SELECT id FROM vehicle_data_source WHERE protocol = 'GB32960' AND source_ip = ?`, legacySourceIP).Scan(&sourceID); err != nil {
+		return fmt.Errorf("lookup legacy data source: %w", err)
+	}
+	if _, err := tx.ExecContext(ctx, `
+INSERT INTO vehicle_daily_mileage_source
+  (vin, stat_date, protocol, source_key, source_ip, source_endpoint, platform_name,
+   first_total_mileage_km, latest_total_mileage_km, daily_mileage_km, sample_count,
+   first_event_time, latest_event_time, quality_status, quality_reason, is_selected)
+SELECT
+  st.vin, st.stat_date, 'GB32960', ?, ?, 'lingniu_prod.ln_vehicle_day_mileage', ?,
+  CASE WHEN st.total_mileage_km IS NOT NULL AND st.total_mileage_km >= st.daily_mileage_km
+       THEN st.total_mileage_km - st.daily_mileage_km ELSE NULL END,
+  st.total_mileage_km, st.daily_mileage_km, 1,
+  TIMESTAMP(st.stat_date, '00:00:00'), TIMESTAMP(st.stat_date, '23:59:59'),
+  'OK', ?, 0
+FROM tmp_legacy_mileage_stage st
+LEFT JOIN vehicle_daily_mileage m
+  ON m.vin = st.vin AND m.stat_date = st.stat_date AND m.protocol = 'GB32960'
+WHERE m.vin IS NULL OR m.daily_mileage_km = 0 OR m.source_id = ?
+ON DUPLICATE KEY UPDATE
+	updated_at = IF(
+		NOT (vehicle_daily_mileage_source.first_total_mileage_km <=> VALUES(first_total_mileage_km))
+		OR NOT (vehicle_daily_mileage_source.latest_total_mileage_km <=> VALUES(latest_total_mileage_km))
+		OR NOT (vehicle_daily_mileage_source.daily_mileage_km <=> VALUES(daily_mileage_km))
+		OR NOT (vehicle_daily_mileage_source.quality_status <=> VALUES(quality_status))
+		OR NOT (vehicle_daily_mileage_source.quality_reason <=> VALUES(quality_reason)),
+		CURRENT_TIMESTAMP,
+		vehicle_daily_mileage_source.updated_at
+	),
+	source_ip = VALUES(source_ip),
+  source_endpoint = VALUES(source_endpoint),
+  platform_name = VALUES(platform_name),
+  first_total_mileage_km = VALUES(first_total_mileage_km),
+  latest_total_mileage_km = VALUES(latest_total_mileage_km),
+  daily_mileage_km = VALUES(daily_mileage_km),
+  sample_count = VALUES(sample_count),
+  first_event_time = VALUES(first_event_time),
+  latest_event_time = VALUES(latest_event_time),
+	quality_status = VALUES(quality_status),
+	quality_reason = VALUES(quality_reason)`, legacySourceKey, legacySourceIP, legacyPlatformName, legacyQuality, sourceID); err != nil {
+		return fmt.Errorf("upsert legacy mileage candidates: %w", err)
+	}
+	if _, err := tx.ExecContext(ctx, `
+INSERT INTO vehicle_daily_mileage
+  (vin, stat_date, protocol, source_id, daily_mileage_km, latest_total_mileage_km)
+SELECT st.vin, st.stat_date, 'GB32960', ?, st.daily_mileage_km, st.total_mileage_km
+FROM tmp_legacy_mileage_stage st
+LEFT JOIN vehicle_daily_mileage m
+  ON m.vin = st.vin AND m.stat_date = st.stat_date AND m.protocol = 'GB32960'
+WHERE m.vin IS NULL OR m.daily_mileage_km = 0 OR m.source_id = ?
+ON DUPLICATE KEY UPDATE
+	updated_at = IF(
+		vehicle_daily_mileage.daily_mileage_km = 0
+		OR (
+			(vehicle_daily_mileage.source_id <=> VALUES(source_id))
+			AND (
+				NOT (vehicle_daily_mileage.daily_mileage_km <=> VALUES(daily_mileage_km))
+				OR NOT (vehicle_daily_mileage.latest_total_mileage_km <=> VALUES(latest_total_mileage_km))
+			)
+		),
+		CURRENT_TIMESTAMP,
+		vehicle_daily_mileage.updated_at
+	),
+	source_id = IF(vehicle_daily_mileage.daily_mileage_km = 0 OR (vehicle_daily_mileage.source_id <=> VALUES(source_id)), VALUES(source_id), vehicle_daily_mileage.source_id),
+	latest_total_mileage_km = IF(vehicle_daily_mileage.daily_mileage_km = 0 OR (vehicle_daily_mileage.source_id <=> VALUES(source_id)), VALUES(latest_total_mileage_km), vehicle_daily_mileage.latest_total_mileage_km),
+	daily_mileage_km = IF(vehicle_daily_mileage.daily_mileage_km = 0 OR (vehicle_daily_mileage.source_id <=> VALUES(source_id)), VALUES(daily_mileage_km), vehicle_daily_mileage.daily_mileage_km)`, sourceID, sourceID); err != nil {
+		return fmt.Errorf("upsert final daily mileage: %w", err)
+	}
+	if _, err := tx.ExecContext(ctx, `
+UPDATE vehicle_daily_mileage_source s
+JOIN tmp_legacy_mileage_stage st
+  ON st.vin = s.vin AND st.stat_date = s.stat_date
+JOIN vehicle_daily_mileage m
+  ON m.vin = st.vin AND m.stat_date = st.stat_date AND m.protocol = 'GB32960'
+SET s.is_selected = CASE WHEN s.source_key = ? THEN 1 ELSE 0 END
+WHERE s.protocol = 'GB32960'
+  AND m.source_id = ?
+  AND ABS(m.daily_mileage_km - st.daily_mileage_km) <= 0.0005`, legacySourceKey, sourceID); err != nil {
+		return fmt.Errorf("mark legacy mileage selections: %w", err)
+	}
+	if err := tx.Commit(); err != nil {
+		return fmt.Errorf("commit migration: %w", err)
+	}
+	return nil
+}
--- a/go/vehicle-gateway/cmd/legacy-mileage-migrate/main_test.go
+++ b/go/vehicle-gateway/cmd/legacy-mileage-migrate/main_test.go
@@ -0,0 +1,56 @@
+package main
+
+import (
+	"database/sql"
+	"testing"
+)
+
+func TestResolveVINPrefersConsistentCurrentMapping(t *testing.T) {
+	current := mappingIndex{Unique: map[string]string{"沪A12345": "LA9GG64L0NBAF4175"}}
+	legacy := mappingIndex{Unique: map[string]string{"沪A12345": "LA9GG64L0NBAF4175"}}
+	vin, origin, conflict := resolveVIN("沪A12345", current, legacy)
+	if conflict || vin != "LA9GG64L0NBAF4175" || origin != "current_vehicle" {
+		t.Fatalf("unexpected resolution: vin=%q origin=%q conflict=%v", vin, origin, conflict)
+	}
+}
+
+func TestResolveVINRejectsCurrentLegacyConflict(t *testing.T) {
+	current := mappingIndex{Unique: map[string]string{"沪A12345": "LA9GG64L0NBAF4175"}}
+	legacy := mappingIndex{Unique: map[string]string{"沪A12345": "LA9GG64L0NBAF4176"}}
+	vin, _, conflict := resolveVIN("沪A12345", current, legacy)
+	if !conflict || vin != "" {
+		t.Fatalf("expected conflict rejection, got vin=%q conflict=%v", vin, conflict)
+	}
+}
+
+func TestResolveVINUsesLegacyFallback(t *testing.T) {
+	current := mappingIndex{Unique: map[string]string{}}
+	legacy := mappingIndex{Unique: map[string]string{"沪A12345": "LA9GG64L0NBAF4175"}}
+	vin, origin, conflict := resolveVIN("沪A12345", current, legacy)
+	if conflict || vin != "LA9GG64L0NBAF4175" || origin != "legacy_vehicle" {
+		t.Fatalf("unexpected resolution: vin=%q origin=%q conflict=%v", vin, origin, conflict)
+	}
+}
+
+func TestResolveVINAcceptsSourceVIN(t *testing.T) {
+	vin, origin, conflict := resolveVIN("LA9GG64L0NBAF4175", mappingIndex{}, mappingIndex{})
+	if conflict || vin != "LA9GG64L0NBAF4175" || origin != "source_vin" {
+		t.Fatalf("unexpected resolution: vin=%q origin=%q conflict=%v", vin, origin, conflict)
+	}
+}
+
+func TestNormalizeIdentifierRemovesWhitespace(t *testing.T) {
+	if got := normalizeIdentifier("  沪 a 12345 \n"); got != "沪A12345" {
+		t.Fatalf("normalizeIdentifier() = %q", got)
+	}
+}
+
+func TestNullableTotalMileageConvertsMetersToKM(t *testing.T) {
+	got := nullableTotalMileageKM(sql.NullFloat64{Float64: 59198000, Valid: true})
+	if got != 59198.0 {
+		t.Fatalf("nullableTotalMileageKM() = %#v", got)
+	}
+	if got := nullableTotalMileageKM(sql.NullFloat64{}); got != nil {
+		t.Fatalf("invalid mileage should remain nil, got %#v", got)
+	}
+}
--- a/go/vehicle-gateway/cmd/stat-writer/main.go
+++ b/go/vehicle-gateway/cmd/stat-writer/main.go
@@ -75,6 +75,13 @@ func main() {
 			os.Exit(1)
 		}
 	}
+	if cfg.HydrogenCapacitySyncEnabled {
+		syncHydrogenCapacities(ctx, logger, registry, db, writer, cfg)
+	} else if loaded, err := writer.ReloadHydrogenTankCapacities(ctx); err != nil {
+		logger.Warn("hydrogen tank capacity cache load failed", "error", err)
+	} else {
+		registry.SetGauge("vehicle_stat_hydrogen_capacity_cache_entries", nil, float64(loaded))
+	}
 	if cfg.NormalizePlatformSourcesOnStart {
 		statDate := time.Now().In(cfg.Location).Format("2006-01-02")
 		normalizeCtx, cancel := context.WithTimeout(ctx, cfg.NormalizePlatformSourcesTimeout)
@@ -108,6 +115,13 @@ func main() {

 	logger.Info("stat writer started", "group", cfg.KafkaGroup, "topics", strings.Join(cfg.KafkaTopics, ","), "workers", cfg.Workers, "project_interval_seconds", cfg.ProjectInterval.Seconds(), "source_touch_interval_seconds", cfg.SourceTouchInterval.Seconds(), "cache_retention_seconds", cfg.CacheRetention.Seconds(), "cache_cleanup_interval_seconds", cfg.CacheCleanupInterval.Seconds(), "baseline_miss_ttl_seconds", cfg.BaselineMissTTL.Seconds(), "baseline_hit_ttl_seconds", cfg.BaselineHitTTL.Seconds(), "cache_max_entries", cfg.CacheMaxEntries, "batch_size", cfg.BatchSize, "batch_wait_ms", cfg.BatchWait, "retry_attempts", cfg.RetryAttempts, "retry_delay_ms", cfg.RetryDelay.Milliseconds(), "quarantine_dir", cfg.QuarantineDir)
 	var background sync.WaitGroup
+	if cfg.HydrogenCapacitySyncEnabled && cfg.HydrogenCapacitySyncInterval > 0 {
+		background.Add(1)
+		go func() {
+			defer background.Done()
+			runHydrogenCapacitySync(ctx, logger, registry, db, writer, cfg)
+		}()
+	}
 	if cfg.ProjectInterval > 0 {
 		background.Add(1)
 		go func() {
@@ -132,6 +146,46 @@ func main() {
 	}
 }

+func runHydrogenCapacitySync(ctx context.Context, logger interface {
+	Info(string, ...any)
+	Warn(string, ...any)
+}, registry *metrics.Registry, db *sql.DB, writer *stats.Writer, cfg config) {
+	ticker := time.NewTicker(cfg.HydrogenCapacitySyncInterval)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ctx.Done():
+			return
+		case <-ticker.C:
+			syncHydrogenCapacities(ctx, logger, registry, db, writer, cfg)
+		}
+	}
+}
+
+func syncHydrogenCapacities(ctx context.Context, logger interface {
+	Info(string, ...any)
+	Warn(string, ...any)
+}, registry *metrics.Registry, db *sql.DB, writer *stats.Writer, cfg config) {
+	syncCtx, cancel := context.WithTimeout(context.WithoutCancel(ctx), cfg.HydrogenCapacitySyncTimeout)
+	defer cancel()
+	result, err := stats.SyncHydrogenTankCapacities(syncCtx, db, cfg.HydrogenCapacitySourceSchema)
+	if err != nil {
+		registry.IncCounter("vehicle_stat_hydrogen_capacity_sync_total", metrics.Labels{"status": "error"})
+		logger.Warn("hydrogen tank capacity sync failed; retaining current cache", "source_schema", cfg.HydrogenCapacitySourceSchema, "error", err)
+		return
+	}
+	loaded, err := writer.ReloadHydrogenTankCapacities(syncCtx)
+	if err != nil {
+		registry.IncCounter("vehicle_stat_hydrogen_capacity_sync_total", metrics.Labels{"status": "cache_error"})
+		logger.Warn("hydrogen tank capacity cache reload failed", "error", err)
+		return
+	}
+	registry.IncCounter("vehicle_stat_hydrogen_capacity_sync_total", metrics.Labels{"status": "ok"})
+	registry.SetGauge("vehicle_stat_hydrogen_capacity_cache_entries", nil, float64(loaded))
+	metrics.RecordLastActivity(registry, "vehicle_stat_hydrogen_capacity_last_sync_unix_seconds", nil)
+	logger.Info("hydrogen tank capacities synchronized", "source_schema", cfg.HydrogenCapacitySourceSchema, "read", result.Read, "written", result.Written, "deactivated", result.Deactivated, "cache_entries", loaded)
+}
+
 type pendingProjectionFlusher interface {
 	FlushPendingProjections(context.Context, time.Time) (stats.ProjectionFlushResult, error)
 }
@@ -790,6 +844,23 @@ func recordStatSampleMetrics(registry *metrics.Registry, message kafka.Message,
 	addStatSampleMetric(registry, message, protocol, "skipped_same_mileage", result.SamplesSkippedSameMileage)
 	addStatSampleMetric(registry, message, protocol, "skipped_missing_source", result.SamplesSkippedMissingSource)
 	addStatSampleMetric(registry, message, protocol, "event_time_future_adjusted", result.SamplesAdjustedFutureEventTime)
+	addHydrogenStreamMetric(registry, message, "found", result.HydrogenSamplesFound)
+	addHydrogenStreamMetric(registry, message, "written", result.HydrogenSamplesWritten)
+	addHydrogenStreamMetric(registry, message, "duplicate_or_late", result.HydrogenSamplesDuplicate)
+	addHydrogenStreamMetric(registry, message, "invalid", result.HydrogenSamplesInvalid)
+	addHydrogenStreamMetric(registry, message, "not_current_date", result.HydrogenSamplesNotCurrent)
+}
+
+func addHydrogenStreamMetric(registry *metrics.Registry, message kafka.Message, status string, count int) {
+	if registry == nil || count == 0 {
+		return
+	}
+	registry.AddCounter("vehicle_stat_hydrogen_stream_total", metrics.Labels{
+		"topic": message.Topic, "status": status,
+	}, float64(count))
+	if status == "written" {
+		metrics.RecordLastActivity(registry, "vehicle_stat_last_hydrogen_stream_write_unix_seconds", metrics.Labels{"status": status})
+	}
 }

 func addStatSampleMetric(registry *metrics.Registry, message kafka.Message, protocol envelope.Protocol, status string, count int) {
@@ -950,6 +1021,10 @@ type config struct {
 	ReconcileProjectionsOnStart     bool
 	ReconcileProjectionsTimeout     time.Duration
 	QuarantineDir                   string
+	HydrogenCapacitySyncEnabled     bool
+	HydrogenCapacitySourceSchema    string
+	HydrogenCapacitySyncInterval    time.Duration
+	HydrogenCapacitySyncTimeout     time.Duration
 }

 func (c config) Validate() error {
@@ -996,6 +1071,10 @@ func loadConfig() config {
 		ReconcileProjectionsOnStart:     env("STATS_RECONCILE_PROJECTIONS_ON_START", "true") != "false",
 		ReconcileProjectionsTimeout:     time.Duration(envInt("STATS_RECONCILE_PROJECTIONS_TIMEOUT_SECONDS", 30)) * time.Second,
 		QuarantineDir:                   env("STATS_QUARANTINE_DIR", "/var/lib/lingniu-go-native/stat-writer-quarantine"),
+		HydrogenCapacitySyncEnabled:     env("HYDROGEN_CAPACITY_SYNC_ENABLED", "true") != "false",
+		HydrogenCapacitySourceSchema:    env("HYDROGEN_CAPACITY_SOURCE_SCHEMA", "ln_asset_management"),
+		HydrogenCapacitySyncInterval:    time.Duration(envInt("HYDROGEN_CAPACITY_SYNC_INTERVAL_SECONDS", 21600)) * time.Second,
+		HydrogenCapacitySyncTimeout:     time.Duration(envInt("HYDROGEN_CAPACITY_SYNC_TIMEOUT_SECONDS", 60)) * time.Second,
 	}
 }

--- a/go/vehicle-gateway/cmd/stats-backfill/main.go
+++ b/go/vehicle-gateway/cmd/stats-backfill/main.go
@@ -57,23 +57,27 @@ type rawFrameRow struct {
 }

 type metricAgg struct {
-	VIN             string
-	Date            string
-	Protocol        envelope.Protocol
-	FirstKM         float64
-	LatestKM        float64
-	Count           int64
-	SourceKey       string
-	Phone           string
-	DeviceID        string
-	SourceEndpoint  string
-	SourceCode      string
-	PlatformName    string
-	SourceKind      string
-	FirstEventTime  time.Time
-	LatestEventTime time.Time
-	QualityStatus   string
-	QualityReason   string
+	VIN                         string
+	Date                        string
+	Protocol                    envelope.Protocol
+	FirstKM                     float64
+	LatestKM                    float64
+	PureHydrogenMileageKM       float64
+	Count                       int64
+	PureHydrogenSampleCount     int64
+	SourceKey                   string
+	Phone                       string
+	DeviceID                    string
+	SourceEndpoint              string
+	SourceCode                  string
+	PlatformName                string
+	SourceKind                  string
+	FirstEventTime              time.Time
+	LatestEventTime             time.Time
+	LatestPureHydrogenActive    bool
+	LatestPureHydrogenModeKnown bool
+	QualityStatus               string
+	QualityReason               string
 }

 type dailySourceLast struct {
@@ -266,21 +270,24 @@ func addSamples(aggregates map[string]*metricAgg, samples []stats.MetricSample)
 		agg, ok := aggregates[key]
 		if !ok {
 			aggregates[key] = &metricAgg{
-				VIN:             sample.VIN,
-				Date:            sample.StatDate,
-				Protocol:        sample.Protocol,
-				FirstKM:         sample.TotalMileageKM,
-				LatestKM:        sample.TotalMileageKM,
-				Count:           1,
-				SourceKey:       sample.SourceKey,
-				Phone:           sample.Phone,
-				DeviceID:        sample.DeviceID,
-				SourceEndpoint:  sample.SourceEndpoint,
-				PlatformName:    sample.PlatformName,
-				FirstEventTime:  sample.EventTime,
-				LatestEventTime: sample.EventTime,
-				QualityStatus:   stats.QualityOK,
-				QualityReason:   "current_day_first_sample",
+				VIN:                         sample.VIN,
+				Date:                        sample.StatDate,
+				Protocol:                    sample.Protocol,
+				FirstKM:                     sample.TotalMileageKM,
+				LatestKM:                    sample.TotalMileageKM,
+				Count:                       1,
+				PureHydrogenSampleCount:     activeModeSampleCount(sample),
+				SourceKey:                   sample.SourceKey,
+				Phone:                       sample.Phone,
+				DeviceID:                    sample.DeviceID,
+				SourceEndpoint:              sample.SourceEndpoint,
+				PlatformName:                sample.PlatformName,
+				FirstEventTime:              sample.EventTime,
+				LatestEventTime:             sample.EventTime,
+				LatestPureHydrogenActive:    sample.PureHydrogenActive,
+				LatestPureHydrogenModeKnown: sample.PureHydrogenModeKnown,
+				QualityStatus:               stats.QualityOK,
+				QualityReason:               "current_day_first_sample",
 			}
 			continue
 		}
@@ -289,8 +296,18 @@ func addSamples(aggregates map[string]*metricAgg, samples []stats.MetricSample)
 			agg.FirstEventTime = sample.EventTime
 		}
 		if sample.EventTime.After(agg.LatestEventTime) {
+			agg.PureHydrogenMileageKM += stats.PureHydrogenMileageDelta(
+				agg.LatestKM,
+				sample.TotalMileageKM,
+				agg.LatestPureHydrogenActive,
+				agg.LatestPureHydrogenModeKnown,
+				sample.PureHydrogenActive,
+				sample.PureHydrogenModeKnown,
+			)
 			agg.LatestKM = sample.TotalMileageKM
 			agg.LatestEventTime = sample.EventTime
+			agg.LatestPureHydrogenActive = sample.PureHydrogenActive
+			agg.LatestPureHydrogenModeKnown = sample.PureHydrogenModeKnown
 			agg.SourceEndpoint = sample.SourceEndpoint
 			if strings.TrimSpace(sample.Phone) != "" {
 				agg.Phone = sample.Phone
@@ -303,9 +320,17 @@ func addSamples(aggregates map[string]*metricAgg, samples []stats.MetricSample)
 			}
 		}
 		agg.Count++
+		agg.PureHydrogenSampleCount += activeModeSampleCount(sample)
 	}
 }

+func activeModeSampleCount(sample stats.MetricSample) int64 {
+	if sample.PureHydrogenModeKnown && sample.PureHydrogenActive {
+		return 1
+	}
+	return 0
+}
+
 func writeAggregates(ctx context.Context, db *sql.DB, aggregates map[string]*metricAgg, batchSize int) (int64, error) {
 	if len(aggregates) == 0 {
 		return 0, nil
@@ -338,23 +363,27 @@ func writeAggregates(ctx context.Context, db *sql.DB, aggregates map[string]*met
 		}
 		dailyKM := stats.DailyMileageFromDayBoundary(agg.FirstKM, agg.LatestKM)
 		candidate := stats.SourceMileageSample{
-			VIN:             agg.VIN,
-			StatDate:        agg.Date,
-			Protocol:        agg.Protocol,
-			SourceKey:       agg.SourceKey,
-			SourceIP:        identity.SourceIP,
-			SourceEndpoint:  agg.SourceEndpoint,
-			Phone:           agg.Phone,
-			DeviceID:        agg.DeviceID,
-			PlatformName:    agg.PlatformName,
-			FirstTotalKM:    agg.FirstKM,
-			LatestTotalKM:   agg.LatestKM,
-			DailyKM:         dailyKM,
-			SampleCount:     agg.Count,
-			FirstEventTime:  agg.FirstEventTime,
-			LatestEventTime: agg.LatestEventTime,
-			QualityStatus:   agg.QualityStatus,
-			QualityReason:   agg.QualityReason,
+			VIN:                         agg.VIN,
+			StatDate:                    agg.Date,
+			Protocol:                    agg.Protocol,
+			SourceKey:                   agg.SourceKey,
+			SourceIP:                    identity.SourceIP,
+			SourceEndpoint:              agg.SourceEndpoint,
+			Phone:                       agg.Phone,
+			DeviceID:                    agg.DeviceID,
+			PlatformName:                agg.PlatformName,
+			FirstTotalKM:                agg.FirstKM,
+			LatestTotalKM:               agg.LatestKM,
+			DailyKM:                     dailyKM,
+			PureHydrogenMileageKM:       agg.PureHydrogenMileageKM,
+			SampleCount:                 agg.Count,
+			PureHydrogenSampleCount:     agg.PureHydrogenSampleCount,
+			FirstEventTime:              agg.FirstEventTime,
+			LatestEventTime:             agg.LatestEventTime,
+			LatestPureHydrogenActive:    agg.LatestPureHydrogenActive,
+			LatestPureHydrogenModeKnown: agg.LatestPureHydrogenModeKnown,
+			QualityStatus:               agg.QualityStatus,
+			QualityReason:               agg.QualityReason,
 		}
 		if candidate.QualityStatus == "" {
 			candidate.QualityStatus = stats.QualityOK
@@ -1266,9 +1295,49 @@ func fieldsForStats(protocol envelope.Protocol, vin string, text string) map[str
 		}
 		fields[key] = value
 	}
+	promoteFuelCellWorkModeForStats(protocol, fields, text)
 	return fields
 }

+func promoteFuelCellWorkModeForStats(protocol envelope.Protocol, fields map[string]any, text string) {
+	if fields == nil {
+		return
+	}
+	if _, exists := fields[envelope.FieldFuelCellWorkMode]; exists {
+		return
+	}
+	var candidates []string
+	switch protocol {
+	case envelope.ProtocolGB32960:
+		candidates = []string{
+			"gb32960.gd_fc_stack.engine_work_state",
+			"engine_work_state",
+		}
+	case envelope.ProtocolYutongMQTT:
+		candidates = []string{
+			"yutong_mqtt.data.triangle_state",
+			"yutong_mqtt.root.data.triangle_state",
+			"TRIANGLE_STATE",
+			"triangle_state",
+			"triangleState",
+		}
+	default:
+		return
+	}
+	for _, key := range candidates {
+		if value, exists := fields[key]; exists {
+			fields[envelope.FieldFuelCellWorkMode] = value
+			return
+		}
+	}
+	for _, key := range candidates {
+		if value, ok := extractJSONStringField(text, key); ok {
+			fields[envelope.FieldFuelCellWorkMode] = value
+			return
+		}
+	}
+}
+
 func mileageKeys(protocol envelope.Protocol) []string {
 	switch protocol {
 	case envelope.ProtocolGB32960:
--- a/go/vehicle-gateway/cmd/stats-backfill/main_test.go
+++ b/go/vehicle-gateway/cmd/stats-backfill/main_test.go
@@ -763,7 +763,8 @@ func TestFieldsForStatsExtractsRawYutongTotalMileage(t *testing.T) {
 	fields := fieldsForStats(envelope.ProtocolYutongMQTT, "LMRKH9AC6R1004108", `{
 	  "data": {
 	    "TOTAL_MILEAGE": 65423000,
-	    "METER_SPEED": 12.3
+	    "METER_SPEED": 12.3,
+	    "TRIANGLE_STATE": 11
 	  },
 	  "root": {
 	    "device": "LMRKH9AC6R1004108"
@@ -773,6 +774,9 @@ func TestFieldsForStatsExtractsRawYutongTotalMileage(t *testing.T) {
 	if got := fields["yutong_mqtt.data.total_mileage"]; got == nil {
 		t.Fatalf("fields missing raw yutong total mileage: %#v", fields)
 	}
+	if got := fields[envelope.FieldFuelCellWorkMode]; got == nil {
+		t.Fatalf("fields missing raw yutong fuel-cell work mode: %#v", fields)
+	}

 	env := envelope.FrameEnvelope{
 		Protocol:     envelope.ProtocolYutongMQTT,
@@ -791,6 +795,32 @@ func TestFieldsForStatsExtractsRawYutongTotalMileage(t *testing.T) {
 	if samples[0].TotalMileageKM != 65423 {
 		t.Fatalf("total mileage km = %v, want 65423", samples[0].TotalMileageKM)
 	}
+	if !samples[0].PureHydrogenModeKnown || !samples[0].PureHydrogenActive {
+		t.Fatalf("pure-hydrogen mode = known:%v active:%v, want known active", samples[0].PureHydrogenModeKnown, samples[0].PureHydrogenActive)
+	}
+}
+
+func TestFieldsForStatsPromotesGB32960FuelCellEngineWorkState(t *testing.T) {
+	fields := fieldsForStats(envelope.ProtocolGB32960, "LTEST000000000001", `{
+	  "data_units": [{
+	    "type": "0x30",
+	    "name": "gd_fc_stack",
+	    "value": {
+	      "summaries": [{"engine_work_state": 2}]
+	    }
+	  }]
+	}`)
+
+	if got := fields[envelope.FieldFuelCellWorkMode]; got == nil {
+		t.Fatalf("fields missing GB32960 fuel-cell work mode: %#v", fields)
+	}
+	active, known := stats.PureHydrogenModeFromEnvelope(envelope.FrameEnvelope{
+		Protocol: envelope.ProtocolGB32960,
+		Fields:   fields,
+	})
+	if !known || !active {
+		t.Fatalf("pure-hydrogen mode = known:%v active:%v, want known active", known, active)
+	}
 }

 func TestClearBackfillTargetMileageClearsExactKey(t *testing.T) {
@@ -863,9 +893,13 @@ func TestWriteAggregatesClearsTargetRowsBeforeStaleCandidateUpsert(t *testing.T)
 			float64(4100),
 			float64(4101),
 			float64(1),
+			float64(0),
 			int64(1),
+			int64(0),
 			projNow,
 			projNow,
+			false,
+			false,
 			stats.QualityInvalidDelta,
 			"outside_daily_range",
 		).
@@ -994,6 +1028,51 @@ func TestAddSamplesUsesCurrentDayFirstSampleBaseline(t *testing.T) {
 	}
 }

+func TestAddSamplesBackfillsOnlyContinuousPureHydrogenIntervals(t *testing.T) {
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	base := stats.MetricSample{
+		VIN:                   "LTEST000000000001",
+		Protocol:              envelope.ProtocolGB32960,
+		StatDate:              "2026-07-08",
+		SourceKey:             "GB32960|127.0.0.1",
+		PureHydrogenModeKnown: true,
+	}
+	samples := []stats.MetricSample{
+		base,
+		base,
+		base,
+		base,
+	}
+	samples[0].TotalMileageKM = 100
+	samples[0].EventTime = time.Date(2026, 7, 8, 8, 0, 0, 0, loc)
+	samples[1].TotalMileageKM = 102
+	samples[1].EventTime = time.Date(2026, 7, 8, 9, 0, 0, 0, loc)
+	samples[1].PureHydrogenActive = true
+	samples[2].TotalMileageKM = 107
+	samples[2].EventTime = time.Date(2026, 7, 8, 10, 0, 0, 0, loc)
+	samples[2].PureHydrogenActive = true
+	samples[3].TotalMileageKM = 110
+	samples[3].EventTime = time.Date(2026, 7, 8, 11, 0, 0, 0, loc)
+
+	aggregates := map[string]*metricAgg{}
+	addSamples(aggregates, samples)
+
+	if len(aggregates) != 1 {
+		t.Fatalf("aggregate count = %d, want 1", len(aggregates))
+	}
+	for _, agg := range aggregates {
+		if agg.PureHydrogenMileageKM != 5 {
+			t.Fatalf("pure-hydrogen mileage = %v, want 5", agg.PureHydrogenMileageKM)
+		}
+		if agg.PureHydrogenSampleCount != 2 {
+			t.Fatalf("pure-hydrogen sample count = %d, want 2", agg.PureHydrogenSampleCount)
+		}
+		if !agg.LatestPureHydrogenModeKnown || agg.LatestPureHydrogenActive {
+			t.Fatalf("latest mode = known:%v active:%v, want known inactive", agg.LatestPureHydrogenModeKnown, agg.LatestPureHydrogenActive)
+		}
+	}
+}
+
 func TestLoadConfigDefaultsBackfillMethodToLastDiff(t *testing.T) {
 	t.Setenv("BACKFILL_METHOD", "")
 	t.Setenv("BACKFILL_DAYS_BACK", "")
--- a/go/vehicle-gateway/internal/envelope/envelope.go
+++ b/go/vehicle-gateway/internal/envelope/envelope.go
@@ -33,11 +33,12 @@ const (
 )

 const (
-	FieldSpeedKMH       = "speed_kmh"
-	FieldTotalMileageKM = "total_mileage_km"
-	FieldLongitude      = "longitude"
-	FieldLatitude       = "latitude"
-	FieldSOCPercent     = "soc_percent"
+	FieldSpeedKMH         = "speed_kmh"
+	FieldTotalMileageKM   = "total_mileage_km"
+	FieldLongitude        = "longitude"
+	FieldLatitude         = "latitude"
+	FieldSOCPercent       = "soc_percent"
+	FieldFuelCellWorkMode = "fuel_cell_work_mode"
 )

 type FrameEnvelope struct {
--- a/go/vehicle-gateway/internal/feichibridge/encoder.go
+++ b/go/vehicle-gateway/internal/feichibridge/encoder.go
@@ -18,7 +18,7 @@ const (

 type Encoder struct{}

-func (Encoder) DataFrame(command byte, vin string, at time.Time, record Record) ([]byte, error) {
+func (e Encoder) DataFrame(command byte, vin string, at time.Time, record Record) ([]byte, error) {
 	if command != CommandRealtime && command != CommandReissue {
 		return nil, fmt.Errorf("unsupported data command 0x%02X", command)
 	}
--- a/go/vehicle-gateway/internal/feichibridge/encoder_test.go
+++ b/go/vehicle-gateway/internal/feichibridge/encoder_test.go
@@ -24,7 +24,7 @@ func TestDataFrameMapsFeichiFields(t *testing.T) {
 		"2607": "1", "2608": "3", "2609": "48",
 		"2610": "1", "2611": "9", "2612": "37",
 		"2003": "1:3.900_3.901_3.902",
-		"2103": "1:35_36_37",
+		"2103": "1:35_36_37", "2115": "44", "2119": "6.0", "100016": "20.8",
 	}
 	frame, err := (Encoder{}).DataFrame(CommandRealtime, "LTEST32960VIN0001", at, record)
 	if err != nil {
@@ -49,6 +49,9 @@ func TestDataFrameMapsFeichiFields(t *testing.T) {
 	if got := env.Fields["longitude"]; got != 113.2644 {
 		t.Fatalf("longitude = %#v", got)
 	}
+	if _, exists := env.Fields["gd_fc_vehicle_hydrogen_mass_kg"]; exists {
+		t.Fatal("bridge must not derive hydrogen mass from platform percentage")
+	}
 }

 func TestDataFrameSplitsMoreThan255CellVoltages(t *testing.T) {
--- a/go/vehicle-gateway/internal/protocol/gb32960/parser.go
+++ b/go/vehicle-gateway/internal/protocol/gb32960/parser.go
@@ -250,6 +250,7 @@ func parseDataBody(version string, body []byte, fields map[string]any) (time.Tim
 			unit := parseGdFCStackData(body[cursor : cursor+size])
 			units = append(units, map[string]any{"type": "0x30", "name": "gd_fc_stack", "value": unit})
 			if summaries, ok := unit["summaries"].([]map[string]any); ok && len(summaries) > 0 {
+				fields[envelope.FieldFuelCellWorkMode] = summaries[0]["engine_work_state"]
 				fields["gd_fc_stack_hydrogen_inlet_pressure_kpa"] = summaries[0]["hydrogen_inlet_pressure_kpa"]
 				fields["gd_fc_stack_water_outlet_temp_c"] = summaries[0]["stack_water_outlet_temp_c"]
 				fields["gd_fc_stack_cell_count"] = summaries[0]["cell_count"]
--- a/go/vehicle-gateway/internal/protocol/gb32960/parser_test.go
+++ b/go/vehicle-gateway/internal/protocol/gb32960/parser_test.go
@@ -197,6 +197,7 @@ func TestParseFrameKeepsParsingRealFuelCellReportUntilUnknownExtension(t *testin
 		t.Fatalf("vin = %q", env.VIN)
 	}
 	assertFloatField(t, env, envelope.FieldTotalMileageKM, 53490.9)
+	assertIntField(t, env, envelope.FieldFuelCellWorkMode, 2)
 	assertFloatField(t, env, "fuel_cell_hydrogen_consumption_kg_per_100km", 1.8)
 	assertFloatField(t, env, envelope.FieldLongitude, 120.800326)
 	assertFloatField(t, env, envelope.FieldLatitude, 31.634907)
--- a/go/vehicle-gateway/internal/protocol/yutongmqtt/parser.go
+++ b/go/vehicle-gateway/internal/protocol/yutongmqtt/parser.go
@@ -115,6 +115,9 @@ func fieldsFromData(data map[string]any) map[string]any {
 	if gear, ok := firstFloat(data, "ON_GEAR", "gear"); ok {
 		fields["gear"] = gear
 	}
+	if workMode, ok := firstFloat(data, "TRIANGLE_STATE", "triangleState", "triangle_state"); ok {
+		fields[envelope.FieldFuelCellWorkMode] = workMode
+	}
 	return fields
 }

--- a/go/vehicle-gateway/internal/protocol/yutongmqtt/parser_test.go
+++ b/go/vehicle-gateway/internal/protocol/yutongmqtt/parser_test.go
@@ -18,7 +18,8 @@ func TestParseMessageMapsYutongPayloadToEnvelope(t *testing.T) {
 	    "BATTERY_CAPACITY_SOC": 70,
 	    "LONGITUDE": 116397128,
 	    "LATITUDE": 39916527,
-	    "GPSDirection": 88
+	    "GPSDirection": 88,
+	    "TRIANGLE_STATE": 11
 	  }
 	}`)

@@ -41,6 +42,7 @@ func TestParseMessageMapsYutongPayloadToEnvelope(t *testing.T) {
 	assertFloatField(t, env, envelope.FieldLongitude, 116.397128)
 	assertFloatField(t, env, envelope.FieldLatitude, 39.916527)
 	assertFloatField(t, env, "direction_deg", 88)
+	assertFloatField(t, env, envelope.FieldFuelCellWorkMode, 11)
 	if env.EventTimeMS == 1782745114999 {
 		t.Fatal("event time should come from device time")
 	}
--- a/go/vehicle-gateway/internal/realtime/openapi.go
+++ b/go/vehicle-gateway/internal/realtime/openapi.go
@@ -468,49 +468,52 @@ func realtimeOpenAPISpec() map[string]any {
 				"DailyMetricRow": map[string]any{
 					"type": "object",
 					"properties": map[string]any{
-						"vin":                     stringSchema("LA9GG64L7PBAF4001"),
-						"stat_date":               stringSchema("2026-07-08"),
-						"protocol":                stringSchema("JT808"),
-						"source_id":               integerSchema(3),
-						"source_ip":               stringSchema("115.231.168.135"),
-						"latest_source_endpoint":  stringSchema("115.231.168.135:41561"),
-						"platform_name":           stringSchema("G7 平台"),
-						"source_code":             stringSchema("G7S"),
-						"source_kind":             stringSchema("PLATFORM"),
-						"daily_mileage_km":        numberSchema(23.1),
-						"latest_total_mileage_km": numberSchema(4123.9),
-						"updated_at":              stringSchema("2026-07-08 13:30:57"),
+						"vin":                      stringSchema("LA9GG64L7PBAF4001"),
+						"stat_date":                stringSchema("2026-07-08"),
+						"protocol":                 stringSchema("JT808"),
+						"source_id":                integerSchema(3),
+						"source_ip":                stringSchema("115.231.168.135"),
+						"latest_source_endpoint":   stringSchema("115.231.168.135:41561"),
+						"platform_name":            stringSchema("G7 平台"),
+						"source_code":              stringSchema("G7S"),
+						"source_kind":              stringSchema("PLATFORM"),
+						"daily_mileage_km":         numberSchema(23.1),
+						"pure_hydrogen_mileage_km": numberSchema(18.6),
+						"latest_total_mileage_km":  numberSchema(4123.9),
+						"updated_at":               stringSchema("2026-07-08 13:30:57"),
 					},
 				},
 				"DailyMetricSourceRow": map[string]any{
 					"type": "object",
 					"properties": map[string]any{
-						"vin":                     stringSchema("LA9GG64L7PBAF4001"),
-						"stat_date":               stringSchema("2026-07-08"),
-						"protocol":                stringSchema("JT808"),
-						"source_key":              stringSchema("JT808:13307795425@115.231.168.135"),
-						"source_ip":               stringSchema("115.231.168.135"),
-						"source_endpoint":         stringSchema("115.231.168.135:41561"),
-						"phone":                   stringSchema("13307795425"),
-						"platform_name":           stringSchema("信达"),
-						"source_id":               integerSchema(5),
-						"source_code":             stringSchema("xinda"),
-						"source_kind":             stringSchema("PLATFORM"),
-						"source_enabled":          map[string]any{"type": "boolean", "example": true},
-						"trust_priority":          integerSchema(10),
-						"first_total_mileage_km":  numberSchema(4100.8),
-						"latest_total_mileage_km": numberSchema(4123.9),
-						"daily_mileage_km":        numberSchema(23.1),
-						"sample_count":            integerSchema(128),
-						"first_event_time":        stringSchema("2026-07-08 00:01:00"),
-						"latest_event_time":       stringSchema("2026-07-08 23:59:00"),
-						"quality_status":          stringSchema("OK"),
-						"quality_reason":          stringSchema("historical_source_baseline"),
-						"is_selected":             map[string]any{"type": "boolean", "example": true},
-						"selection_status":        stringSchema("selected"),
-						"selection_reason":        stringSchema("selected_current_projection"),
-						"selection_action":        stringSchema("当前来源已被投影到最终日里程表"),
-						"updated_at":              stringSchema("2026-07-08 23:59:10"),
+						"vin":                        stringSchema("LA9GG64L7PBAF4001"),
+						"stat_date":                  stringSchema("2026-07-08"),
+						"protocol":                   stringSchema("JT808"),
+						"source_key":                 stringSchema("JT808:13307795425@115.231.168.135"),
+						"source_ip":                  stringSchema("115.231.168.135"),
+						"source_endpoint":            stringSchema("115.231.168.135:41561"),
+						"phone":                      stringSchema("13307795425"),
+						"platform_name":              stringSchema("信达"),
+						"source_id":                  integerSchema(5),
+						"source_code":                stringSchema("xinda"),
+						"source_kind":                stringSchema("PLATFORM"),
+						"source_enabled":             map[string]any{"type": "boolean", "example": true},
+						"trust_priority":             integerSchema(10),
+						"first_total_mileage_km":     numberSchema(4100.8),
+						"latest_total_mileage_km":    numberSchema(4123.9),
+						"daily_mileage_km":           numberSchema(23.1),
+						"pure_hydrogen_mileage_km":   numberSchema(18.6),
+						"pure_hydrogen_sample_count": integerSchema(42),
+						"sample_count":               integerSchema(128),
+						"first_event_time":           stringSchema("2026-07-08 00:01:00"),
+						"latest_event_time":          stringSchema("2026-07-08 23:59:00"),
+						"quality_status":             stringSchema("OK"),
+						"quality_reason":             stringSchema("historical_source_baseline"),
+						"is_selected":                map[string]any{"type": "boolean", "example": true},
+						"selection_status":           stringSchema("selected"),
+						"selection_reason":           stringSchema("selected_current_projection"),
+						"selection_action":           stringSchema("当前来源已被投影到最终日里程表"),
+						"updated_at":                 stringSchema("2026-07-08 23:59:10"),
 					},
 				},
 				"DailyMetricSourceQualityRow": map[string]any{
--- a/go/vehicle-gateway/internal/stats/daily_metric.go
+++ b/go/vehicle-gateway/internal/stats/daily_metric.go
@@ -53,20 +53,23 @@ type Writer struct {
 	projectionKeysByPrefix  map[string]map[string]struct{}
 	baselineKeysByPrefix    map[string]map[string]struct{}
 	lastGPSAccumulation     map[string]time.Time
+	hydrogenTankCapacities  map[string]float64
 	gpsAccumulationInterval time.Duration
 }

 type MetricSample struct {
-	VIN            string
-	Protocol       envelope.Protocol
-	StatDate       string
-	TotalMileageKM float64
-	EventTime      time.Time
-	SourceKey      string
-	Phone          string
-	DeviceID       string
-	SourceEndpoint string
-	PlatformName   string
+	VIN                   string
+	Protocol              envelope.Protocol
+	StatDate              string
+	TotalMileageKM        float64
+	EventTime             time.Time
+	SourceKey             string
+	Phone                 string
+	DeviceID              string
+	SourceEndpoint        string
+	PlatformName          string
+	PureHydrogenActive    bool
+	PureHydrogenModeKnown bool
 }

 type AppendResult struct {
@@ -91,6 +94,11 @@ type AppendResult struct {
 	ProjectionsAttempted             int
 	ProjectionsWritten               int
 	ProjectionsSkippedThrottled      int
+	HydrogenSamplesFound             int
+	HydrogenSamplesWritten           int
+	HydrogenSamplesDuplicate         int
+	HydrogenSamplesInvalid           int
+	HydrogenSamplesNotCurrent        int
 }

 type ProjectionFlushResult struct {
@@ -161,6 +169,7 @@ func NewWriter(exec Execer, loc *time.Location) *Writer {
 		projectionKeysByPrefix:  map[string]map[string]struct{}{},
 		baselineKeysByPrefix:    map[string]map[string]struct{}{},
 		lastGPSAccumulation:     map[string]time.Time{},
+		hydrogenTankCapacities:  map[string]float64{},
 		gpsAccumulationInterval: defaultGPSAccumulationInterval,
 	}
 	if query, ok := exec.(Queryer); ok {
@@ -169,6 +178,25 @@ func NewWriter(exec Execer, loc *time.Location) *Writer {
 	return writer
 }

+func (w *Writer) ReloadHydrogenTankCapacities(ctx context.Context) (int, error) {
+	capacities, err := LoadHydrogenTankCapacities(ctx, w.query)
+	if err != nil {
+		return 0, err
+	}
+	w.mu.Lock()
+	w.hydrogenTankCapacities = capacities
+	w.mu.Unlock()
+	return len(capacities), nil
+}
+
+func (w *Writer) HydrogenTankCapacityLiters(vin string) (float64, bool) {
+	vin = strings.ToUpper(strings.TrimSpace(vin))
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	capacity, ok := w.hydrogenTankCapacities[vin]
+	return capacity, ok
+}
+
 func (w *Writer) SetSourceTouchInterval(interval time.Duration) {
 	w.mu.Lock()
 	defer w.mu.Unlock()
@@ -273,6 +301,8 @@ func (w *Writer) EnsureSchema(ctx context.Context) error {
 		GPSMileageStateTableSQL,
 		DailyMileageSourceTableSQL,
 		DailyMileageTableSQL,
+		HydrogenTankCapacityTableSQL,
+		HydrogenStreamStateTableSQL,
 	} {
 		if _, err := w.exec.ExecContext(ctx, statement); err != nil {
 			return err
@@ -300,6 +330,16 @@ func (w *Writer) AppendWithResult(ctx context.Context, env envelope.FrameEnvelop
 	seenAt := w.sourceSeenAt(env)
 	w.maybeCleanupCaches(seenAt)
 	identity, hasSource := NewSourceIdentityFromEnvelope(env)
+	capacityLiters, _ := w.HydrogenTankCapacityLiters(env.VIN)
+	hydrogen, err := AppendHydrogenStream(ctx, w.exec, env, w.loc, time.Now(), capacityLiters)
+	if err != nil {
+		return result, err
+	}
+	result.HydrogenSamplesFound = hydrogen.Found
+	result.HydrogenSamplesWritten = hydrogen.Written
+	result.HydrogenSamplesDuplicate = hydrogen.Duplicate
+	result.HydrogenSamplesInvalid = hydrogen.Invalid
+	result.HydrogenSamplesNotCurrent = hydrogen.NotCurrent
 	var sourceResult AppendResult
 	if hasSource && ShouldManageDataSource(identity) {
 		if w.shouldTouchSource(identity, seenAt) {
@@ -316,6 +356,11 @@ func (w *Writer) AppendWithResult(ctx context.Context, env envelope.FrameEnvelop
 		sourceResult.SourceTouchesSkippedUnmanaged = 1
 	}
 	samples, extractionResult, err := samplesFromEnvelopeWithResult(env, w.loc)
+	extractionResult.HydrogenSamplesFound = result.HydrogenSamplesFound
+	extractionResult.HydrogenSamplesWritten = result.HydrogenSamplesWritten
+	extractionResult.HydrogenSamplesDuplicate = result.HydrogenSamplesDuplicate
+	extractionResult.HydrogenSamplesInvalid = result.HydrogenSamplesInvalid
+	extractionResult.HydrogenSamplesNotCurrent = result.HydrogenSamplesNotCurrent
 	result = extractionResult
 	result.SourceTouchesAttempted += sourceResult.SourceTouchesAttempted
 	result.SourceTouchesWritten += sourceResult.SourceTouchesWritten
@@ -1191,18 +1236,21 @@ func samplesFromEnvelopeWithResult(env envelope.FrameEnvelope, loc *time.Locatio
 		result.SamplesAdjustedFutureEventTime = 1
 	}
 	statDate := time.UnixMilli(eventMS).In(loc).Format("2006-01-02")
+	pureHydrogenActive, pureHydrogenModeKnown := PureHydrogenModeFromEnvelope(env)
 	result.SamplesFound = 1
 	return []MetricSample{{
-		VIN:            vin,
-		Protocol:       env.Protocol,
-		StatDate:       statDate,
-		TotalMileageKM: totalMileage,
-		EventTime:      time.UnixMilli(eventMS).In(loc),
-		SourceKey:      sourceKey(env),
-		Phone:          strings.TrimSpace(env.Phone),
-		DeviceID:       strings.TrimSpace(env.DeviceID),
-		SourceEndpoint: strings.TrimSpace(env.SourceEndpoint),
-		PlatformName:   strings.TrimSpace(env.PlatformName),
+		VIN:                   vin,
+		Protocol:              env.Protocol,
+		StatDate:              statDate,
+		TotalMileageKM:        totalMileage,
+		EventTime:             time.UnixMilli(eventMS).In(loc),
+		SourceKey:             sourceKey(env),
+		Phone:                 strings.TrimSpace(env.Phone),
+		DeviceID:              strings.TrimSpace(env.DeviceID),
+		SourceEndpoint:        strings.TrimSpace(env.SourceEndpoint),
+		PlatformName:          strings.TrimSpace(env.PlatformName),
+		PureHydrogenActive:    pureHydrogenActive,
+		PureHydrogenModeKnown: pureHydrogenModeKnown,
 	}}, result, nil
 }

--- a/go/vehicle-gateway/internal/stats/daily_metric_test.go
+++ b/go/vehicle-gateway/internal/stats/daily_metric_test.go
@@ -118,6 +118,40 @@ func TestSamplesFromEnvelopeMapsProtocolMileageFields(t *testing.T) {
 	}
 }

+func TestSamplesFromEnvelopeCarriesPureHydrogenWorkMode(t *testing.T) {
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	tests := []struct {
+		name     string
+		protocol envelope.Protocol
+		mode     int
+	}{
+		{name: "gb32960 fuel cell engine running", protocol: envelope.ProtocolGB32960, mode: 2},
+		{name: "yutong fuel cell driving", protocol: envelope.ProtocolYutongMQTT, mode: 11},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			fields := map[string]any{envelope.FieldFuelCellWorkMode: test.mode}
+			if test.protocol == envelope.ProtocolGB32960 {
+				fields["gb32960.vehicle.total_mileage_km"] = 12000.5
+			} else {
+				fields["yutong_mqtt.data.total_mileage"] = 12000500
+			}
+			samples, err := SamplesFromEnvelope(envelope.FrameEnvelope{
+				Protocol:    test.protocol,
+				VIN:         "LNBVIN00000000001",
+				EventTimeMS: time.Date(2026, 7, 23, 8, 30, 0, 0, loc).UnixMilli(),
+				Fields:      fields,
+			}, loc)
+			if err != nil || len(samples) != 1 {
+				t.Fatalf("SamplesFromEnvelope() samples=%d error=%v", len(samples), err)
+			}
+			if !samples[0].PureHydrogenModeKnown || !samples[0].PureHydrogenActive {
+				t.Fatalf("pure hydrogen evidence missing: %#v", samples[0])
+			}
+		})
+	}
+}
+
 func TestSamplesFromEnvelopeFallsBackToReceivedTimeWhenEventTimeIsFuture(t *testing.T) {
 	loc := time.FixedZone("Asia/Shanghai", 8*3600)
 	received := time.Date(2026, 7, 8, 23, 59, 0, 0, loc)
@@ -1035,9 +1069,13 @@ func TestWriterAppendUsesCurrentSampleWhenNoHistoricalBaseline(t *testing.T) {
 			float64(4123.9),
 			float64(4123.9),
 			float64(0),
+			float64(0),
 			int64(1),
+			int64(0),
 			eventTime,
 			eventTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonCurrentDayFirst,
 		).
@@ -1115,9 +1153,13 @@ func TestWriterCachesMissingBaselineAfterSuccessfulFirstSample(t *testing.T) {
 			float64(4123.9),
 			float64(4123.9),
 			float64(0),
+			float64(0),
 			int64(1),
+			int64(0),
 			firstTime,
 			firstTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonCurrentDayFirst,
 		).
@@ -1161,9 +1203,13 @@ func TestWriterCachesMissingBaselineAfterSuccessfulFirstSample(t *testing.T) {
 			float64(4123.9),
 			float64(4124.4),
 			approxFloat64{want: 0.5, tolerance: 0.000001},
+			float64(0),
 			int64(1),
+			int64(0),
 			firstTime,
 			secondTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonCurrentDayFirst,
 		).
@@ -1356,9 +1402,13 @@ func TestWriterAppendUsesPreviousSourceBaselineForRealtimeCandidate(t *testing.T
 			float64(4100.8),
 			float64(4123.9),
 			approxFloat64{want: 23.1, tolerance: 0.000001},
+			float64(0),
 			int64(1),
+			int64(0),
 			previousTime,
 			currentTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonHistorical,
 		).
@@ -1441,9 +1491,13 @@ func TestWriterAppendUsesOlderHistoricalSourceBaseline(t *testing.T) {
 			float64(120672.0),
 			float64(120788.0),
 			approxFloat64{want: 116.0, tolerance: 0.000001},
+			float64(0),
 			int64(1),
+			int64(0),
 			historicalTime,
 			currentTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonHistorical,
 		).
@@ -1776,9 +1830,13 @@ func TestWriterAppendMarksCandidateNoPreviousBaselineWhenPreviousBaselineMissing
 			float64(4136.8),
 			float64(4136.8),
 			float64(0),
+			float64(0),
 			int64(1),
+			int64(0),
 			currentTime,
 			currentTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonCurrentDayFirst,
 		).
@@ -1836,7 +1894,7 @@ func TestWriterEnsuresSchemaAndUpsertsDailyMileage(t *testing.T) {
 		t.Fatalf("Append() error = %v", err)
 	}

-	schemaCalls := 4 + len(DailyMileageAlterSQL)
+	schemaCalls := 6 + len(DailyMileageAlterSQL)
 	if len(exec.calls) != schemaCalls+5 {
 		t.Fatalf("exec calls = %d", len(exec.calls))
 	}
@@ -1845,6 +1903,8 @@ func TestWriterEnsuresSchemaAndUpsertsDailyMileage(t *testing.T) {
 		"CREATE TABLE IF NOT EXISTS vehicle_daily_gps_mileage_state",
 		"CREATE TABLE IF NOT EXISTS vehicle_daily_mileage_source",
 		"CREATE TABLE IF NOT EXISTS vehicle_daily_mileage",
+		"CREATE TABLE IF NOT EXISTS vehicle_hydrogen_tank_capacity",
+		"CREATE TABLE IF NOT EXISTS vehicle_open_hydrogen_stream_state",
 	} {
 		if !strings.Contains(exec.calls[i].query, want) {
 			t.Fatalf("schema call %d = %s, want %s", i, exec.calls[i].query, want)
@@ -2040,7 +2100,7 @@ func TestWriterCarriesPreviousYutongMileageIntoStationaryDay(t *testing.T) {
 	if got := sourceWrite.args[11]; got != float64(0) {
 		t.Fatalf("daily mileage = %#v, want explicit zero", got)
 	}
-	if got := sourceWrite.args[16]; got != QualityReasonStationaryCarry {
+	if got := sourceWrite.args[20]; got != QualityReasonStationaryCarry {
 		t.Fatalf("quality reason = %#v, want %q", got, QualityReasonStationaryCarry)
 	}
 }
@@ -2249,9 +2309,13 @@ func TestWriterRollsBackMileageTransactionWhenProjectionFails(t *testing.T) {
 			float64(4123.9),
 			float64(4123.9),
 			float64(0),
+			float64(0),
 			int64(1),
+			int64(0),
 			eventTime,
 			eventTime,
+			false,
+			false,
 			QualityOK,
 			QualityReasonCurrentDayFirst,
 		).
--- a/go/vehicle-gateway/internal/stats/hydrogen_capacity.go
+++ b/go/vehicle-gateway/internal/stats/hydrogen_capacity.go
@@ -0,0 +1,149 @@
+package stats
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+const HydrogenTankCapacityTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_hydrogen_tank_capacity (
+  vin VARCHAR(64) NOT NULL,
+  source_vehicle_id BIGINT NOT NULL,
+  source_model_id BIGINT NULL,
+  plate_number VARCHAR(50) NOT NULL DEFAULT '',
+  brand_name VARCHAR(500) NOT NULL DEFAULT '',
+  model_name VARCHAR(500) NOT NULL DEFAULT '',
+  tank_capacity_l DECIMAL(12,2) NOT NULL,
+  active TINYINT(1) NOT NULL DEFAULT 1,
+  source_updated_at DATETIME NULL,
+  synced_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+  PRIMARY KEY (vin),
+  KEY idx_hydrogen_capacity_model (source_model_id),
+  KEY idx_hydrogen_capacity_active (active,vin)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci`
+
+type HydrogenCapacitySyncResult struct {
+	Read        int
+	Written     int
+	Deactivated int64
+}
+
+type hydrogenCapacityRow struct {
+	VIN             string
+	SourceVehicleID int64
+	SourceModelID   sql.NullInt64
+	Plate           string
+	Brand           string
+	Model           string
+	CapacityLiters  float64
+	SourceUpdatedAt sql.NullTime
+}
+
+var mysqlIdentifier = regexp.MustCompile(`^[A-Za-z0-9_]+$`)
+
+func SyncHydrogenTankCapacities(ctx context.Context, db *sql.DB, sourceSchema string) (HydrogenCapacitySyncResult, error) {
+	result := HydrogenCapacitySyncResult{}
+	if db == nil {
+		return result, fmt.Errorf("mysql database is required")
+	}
+	sourceSchema = strings.TrimSpace(sourceSchema)
+	if !mysqlIdentifier.MatchString(sourceSchema) {
+		return result, fmt.Errorf("invalid asset schema %q", sourceSchema)
+	}
+	query := fmt.Sprintf(`SELECT vi.id,vi.vehicle_model_id,UPPER(TRIM(vi.vin)),COALESCE(vi.plate_number,''),
+COALESCE(vm.brand,''),COALESCE(vm.model,''),vm.tank_capacity,
+CASE
+  WHEN vi.update_time IS NULL THEN vm.update_time
+  WHEN vm.update_time IS NULL THEN vi.update_time
+  ELSE GREATEST(vi.update_time,vm.update_time)
+END
+FROM %s.vehicle_info vi
+JOIN %s.vehicle_model vm ON vm.id=vi.vehicle_model_id
+WHERE COALESCE(vi.del_flag,'0')='0' AND COALESCE(vm.del_flag,'0')='0'
+  AND LENGTH(TRIM(vi.vin))=17 AND vm.tank_capacity>0`, sourceSchema, sourceSchema)
+	rows, err := db.QueryContext(ctx, query)
+	if err != nil {
+		return result, fmt.Errorf("read asset hydrogen capacities: %w", err)
+	}
+	byVIN := map[string]hydrogenCapacityRow{}
+	for rows.Next() {
+		var row hydrogenCapacityRow
+		if err := rows.Scan(&row.SourceVehicleID, &row.SourceModelID, &row.VIN, &row.Plate, &row.Brand, &row.Model, &row.CapacityLiters, &row.SourceUpdatedAt); err != nil {
+			rows.Close()
+			return result, err
+		}
+		result.Read++
+		if row.CapacityLiters <= 0 || row.CapacityLiters > 10000 {
+			continue
+		}
+		if previous, exists := byVIN[row.VIN]; !exists || newerCapacityRow(row, previous) {
+			byVIN[row.VIN] = row
+		}
+	}
+	if err := rows.Close(); err != nil {
+		return result, err
+	}
+	tx, err := db.BeginTx(ctx, nil)
+	if err != nil {
+		return result, err
+	}
+	defer tx.Rollback()
+	_, err = tx.ExecContext(ctx, `UPDATE vehicle_hydrogen_tank_capacity SET active=0 WHERE active=1`)
+	if err != nil {
+		return result, err
+	}
+	const upsert = `INSERT INTO vehicle_hydrogen_tank_capacity(
+vin,source_vehicle_id,source_model_id,plate_number,brand_name,model_name,tank_capacity_l,active,source_updated_at,synced_at
+) VALUES(?,?,?,?,?,?,?,1,?,NOW(3))
+ON DUPLICATE KEY UPDATE source_vehicle_id=VALUES(source_vehicle_id),source_model_id=VALUES(source_model_id),
+plate_number=VALUES(plate_number),brand_name=VALUES(brand_name),model_name=VALUES(model_name),
+tank_capacity_l=VALUES(tank_capacity_l),active=1,source_updated_at=VALUES(source_updated_at),synced_at=NOW(3)`
+	for _, row := range byVIN {
+		if _, err := tx.ExecContext(ctx, upsert, row.VIN, row.SourceVehicleID, row.SourceModelID, row.Plate, row.Brand, row.Model, row.CapacityLiters, row.SourceUpdatedAt); err != nil {
+			return result, err
+		}
+		result.Written++
+	}
+	if err := tx.QueryRowContext(ctx, `SELECT COUNT(*) FROM vehicle_hydrogen_tank_capacity WHERE active=0`).Scan(&result.Deactivated); err != nil {
+		return result, err
+	}
+	if err := tx.Commit(); err != nil {
+		return result, err
+	}
+	return result, nil
+}
+
+func newerCapacityRow(left, right hydrogenCapacityRow) bool {
+	if left.SourceUpdatedAt.Valid != right.SourceUpdatedAt.Valid {
+		return left.SourceUpdatedAt.Valid
+	}
+	if left.SourceUpdatedAt.Valid && !left.SourceUpdatedAt.Time.Equal(right.SourceUpdatedAt.Time) {
+		return left.SourceUpdatedAt.Time.After(right.SourceUpdatedAt.Time)
+	}
+	return left.SourceVehicleID > right.SourceVehicleID
+}
+
+func LoadHydrogenTankCapacities(ctx context.Context, query Queryer) (map[string]float64, error) {
+	if query == nil {
+		return nil, fmt.Errorf("mysql queryer is required")
+	}
+	rows, err := query.QueryContext(ctx, `SELECT UPPER(TRIM(vin)),tank_capacity_l FROM vehicle_hydrogen_tank_capacity WHERE active=1 AND tank_capacity_l>0`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	capacities := map[string]float64{}
+	for rows.Next() {
+		var vin string
+		var capacity float64
+		if err := rows.Scan(&vin, &capacity); err != nil {
+			return nil, err
+		}
+		if len(vin) == 17 && capacity > 0 && capacity <= 10000 {
+			capacities[vin] = capacity
+		}
+	}
+	return capacities, rows.Err()
+}
--- a/go/vehicle-gateway/internal/stats/hydrogen_capacity_test.go
+++ b/go/vehicle-gateway/internal/stats/hydrogen_capacity_test.go
@@ -0,0 +1,72 @@
+package stats
+
+import (
+	"context"
+	"regexp"
+	"testing"
+	"time"
+
+	"github.com/DATA-DOG/go-sqlmock"
+)
+
+func TestSyncHydrogenTankCapacitiesCopiesAssetMasterData(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	updatedAt := time.Date(2026, 7, 21, 10, 0, 0, 0, time.Local)
+	mock.ExpectQuery("FROM ln_asset_management\\.vehicle_info vi").
+		WillReturnRows(sqlmock.NewRows([]string{"id", "vehicle_model_id", "vin", "plate", "brand", "model", "tank_capacity", "updated_at"}).
+			AddRow(1001, 51, "LA9GG64L0NBAF4175", "浙F06618F", "feichi", "49吨牵引车头", 1400.0, updatedAt))
+	mock.ExpectBegin()
+	mock.ExpectExec(regexp.QuoteMeta("UPDATE vehicle_hydrogen_tank_capacity SET active=0 WHERE active=1")).
+		WillReturnResult(sqlmock.NewResult(0, 20))
+	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_hydrogen_tank_capacity(")).
+		WithArgs("LA9GG64L0NBAF4175", int64(1001), sqlmock.AnyArg(), "浙F06618F", "feichi", "49吨牵引车头", 1400.0, sqlmock.AnyArg()).
+		WillReturnResult(sqlmock.NewResult(1, 1))
+	mock.ExpectQuery(regexp.QuoteMeta("SELECT COUNT(*) FROM vehicle_hydrogen_tank_capacity WHERE active=0")).
+		WillReturnRows(sqlmock.NewRows([]string{"count"}).AddRow(0))
+	mock.ExpectCommit()
+
+	result, err := SyncHydrogenTankCapacities(context.Background(), db, "ln_asset_management")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.Read != 1 || result.Written != 1 || result.Deactivated != 0 {
+		t.Fatalf("result=%+v", result)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestSyncHydrogenTankCapacitiesRejectsUnsafeSchema(t *testing.T) {
+	db, _, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	if _, err := SyncHydrogenTankCapacities(context.Background(), db, "ln_asset_management;DROP"); err == nil {
+		t.Fatal("unsafe schema accepted")
+	}
+}
+
+func TestLoadHydrogenTankCapacitiesBuildsVINMap(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	mock.ExpectQuery("SELECT UPPER\\(TRIM\\(vin\\)\\),tank_capacity_l").
+		WillReturnRows(sqlmock.NewRows([]string{"vin", "capacity"}).
+			AddRow("LA9GG64L0NBAF4175", 1400.0).
+			AddRow("LB9A32A24R0LS1037", 380.0))
+	capacities, err := LoadHydrogenTankCapacities(context.Background(), db)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if capacities["LA9GG64L0NBAF4175"] != 1400 || capacities["LB9A32A24R0LS1037"] != 380 {
+		t.Fatalf("capacities=%v", capacities)
+	}
+}
--- a/go/vehicle-gateway/internal/stats/hydrogen_stream.go
+++ b/go/vehicle-gateway/internal/stats/hydrogen_stream.go
@@ -0,0 +1,270 @@
+package stats
+
+import (
+	"context"
+	"database/sql"
+	"math"
+	"strings"
+	"time"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/telemetry"
+)
+
+const (
+	defaultHydrogenNoiseKG    = 0.05
+	defaultHydrogenMaxDropKG  = 20.0
+	hydrogenMolarMassKGPerMol = 0.00201588
+	universalGasConstant      = 8.314472
+)
+
+var hydrogenPressureFieldKeys = []string{
+	"gb32960.fuel_cell.max_hydrogen_pressure_mpa",
+	"fuel_cell_max_hydrogen_pressure_mpa",
+}
+
+var hydrogenTemperatureFieldKeys = []string{
+	"gb32960.fuel_cell.max_hydrogen_temperature_c",
+	"fuel_cell_max_hydrogen_temperature_c",
+}
+
+var hydrogenDensityA = [...]float64{0.05888460, -0.06136111, -0.002650473, 0.002731125, 0.001802374, -0.001150707, 0.00009588528, -0.0000001109040, 0.0000000001264403}
+var hydrogenDensityB = [...]float64{1.325, 1.87, 2.5, 2.8, 2.938, 3.14, 3.37, 3.75, 4.0}
+var hydrogenDensityC = [...]float64{1, 1, 2, 2, 2.42, 2.63, 3, 4, 5}
+
+const HydrogenStreamStateTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_open_hydrogen_stream_state (
+  vin VARCHAR(64) NOT NULL,
+  stat_date DATE NOT NULL,
+  source_endpoint VARCHAR(128) NOT NULL DEFAULT '',
+  first_mass_kg DECIMAL(18,3) NOT NULL,
+	last_mass_kg DECIMAL(18,3) NOT NULL,
+	cycle_min_mass_kg DECIMAL(18,3) NOT NULL,
+  consumption_kg DECIMAL(18,3) NOT NULL DEFAULT 0,
+  sample_count BIGINT UNSIGNED NOT NULL DEFAULT 1,
+  refuel_count INT UNSIGNED NOT NULL DEFAULT 0,
+  abnormal_drop_count INT UNSIGNED NOT NULL DEFAULT 0,
+  tank_capacity_l DECIMAL(12,2) NOT NULL,
+  first_pressure_mpa DECIMAL(10,3) NOT NULL,
+  last_pressure_mpa DECIMAL(10,3) NOT NULL,
+  first_temperature_c DECIMAL(10,3) NOT NULL,
+  last_temperature_c DECIMAL(10,3) NOT NULL,
+  calculation_method VARCHAR(32) NOT NULL DEFAULT 'PRESSURE_NIST',
+  first_event_time DATETIME(3) NOT NULL,
+  last_event_time DATETIME(3) NOT NULL,
+  last_event_id VARCHAR(128) NOT NULL DEFAULT '',
+  quality_status VARCHAR(24) NOT NULL DEFAULT 'NO_DATA',
+  quality_reason VARCHAR(255) NOT NULL DEFAULT '有效压力质量样本不足2条',
+  created_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+  updated_at DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3) ON UPDATE CURRENT_TIMESTAMP(3),
+  PRIMARY KEY (vin, stat_date, source_endpoint),
+  KEY idx_hydrogen_stream_date_quality (stat_date, quality_status, vin)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci`
+
+type HydrogenStreamSample struct {
+	VIN                string
+	Date               string
+	SourceEndpoint     string
+	EventID            string
+	EventTime          time.Time
+	MassKG             float64
+	TankCapacityLiters float64
+	PressureMPa        float64
+	TemperatureC       float64
+	NoiseKG            float64
+	RefuelThresholdKG  float64
+}
+
+type HydrogenStreamResult struct {
+	Found      int
+	Written    int
+	Duplicate  int
+	Invalid    int
+	NotCurrent int
+}
+
+func HydrogenDensityKGPerM3(pressureMPa, temperatureC float64) (float64, bool) {
+	temperatureK := temperatureC + 273.15
+	if pressureMPa < 0 || pressureMPa > 70 || temperatureK < 220 || temperatureK > 1000 {
+		return 0, false
+	}
+	z := 1.0
+	for i := range hydrogenDensityA {
+		z += hydrogenDensityA[i] * math.Pow(100/temperatureK, hydrogenDensityB[i]) * math.Pow(pressureMPa, hydrogenDensityC[i])
+	}
+	if z <= 0 {
+		return 0, false
+	}
+	molPerLiter := pressureMPa * 1000 / (universalGasConstant * temperatureK * z)
+	return molPerLiter * hydrogenMolarMassKGPerMol * 1000, true
+}
+
+func PressureHydrogenMassKG(pressureMPa, temperatureC, tankCapacityLiters float64) (float64, bool) {
+	if tankCapacityLiters <= 0 || tankCapacityLiters > 10000 {
+		return 0, false
+	}
+	density, ok := HydrogenDensityKGPerM3(pressureMPa, temperatureC)
+	if !ok {
+		return 0, false
+	}
+	mass := density * tankCapacityLiters / 1000
+	return mass, !math.IsNaN(mass) && !math.IsInf(mass, 0) && mass >= 0 && mass <= 500
+}
+
+func HydrogenStreamSampleFromEnvelope(env envelope.FrameEnvelope, loc *time.Location, now time.Time, tankCapacityLiters float64) (HydrogenStreamSample, string, bool) {
+	if env.Protocol != envelope.ProtocolGB32960 {
+		return HydrogenStreamSample{}, "unsupported_protocol", false
+	}
+	vin := strings.ToUpper(strings.TrimSpace(env.VIN))
+	if len(vin) != 17 {
+		return HydrogenStreamSample{}, "invalid_vin", false
+	}
+	pressure, pressureOK := firstHydrogenNumber(env.Fields, hydrogenPressureFieldKeys)
+	if !pressureOK {
+		return HydrogenStreamSample{}, "missing_pressure", false
+	}
+	temperature, temperatureOK := firstHydrogenNumber(env.Fields, hydrogenTemperatureFieldKeys)
+	if !temperatureOK {
+		return HydrogenStreamSample{}, "missing_temperature", false
+	}
+	if tankCapacityLiters <= 0 || tankCapacityLiters > 10000 {
+		return HydrogenStreamSample{}, "missing_tank_capacity", false
+	}
+	mass, ok := PressureHydrogenMassKG(pressure, temperature, tankCapacityLiters)
+	if !ok {
+		return HydrogenStreamSample{}, "invalid_pressure_mass", false
+	}
+	pressureStepMass, _ := PressureHydrogenMassKG(math.Max(0, pressure-0.2), temperature, tankCapacityLiters)
+	noiseKG := math.Max(defaultHydrogenNoiseKG, mass-pressureStepMass)
+	noiseKG = math.Min(noiseKG, 1.0)
+	refuelThresholdKG := math.Max(1.0, mass*0.05)
+	if loc == nil {
+		loc = time.FixedZone("Asia/Shanghai", 8*3600)
+	}
+	eventMS, _, ok := envelope.NormalizedEventTimeMSWithReason(env)
+	if !ok {
+		return HydrogenStreamSample{}, "missing_event_time", false
+	}
+	eventTime := time.UnixMilli(eventMS).In(loc)
+	if now.IsZero() {
+		now = time.Now()
+	}
+	date := eventTime.Format("2006-01-02")
+	if date != now.In(loc).Format("2006-01-02") {
+		return HydrogenStreamSample{}, "not_current_date", false
+	}
+	return HydrogenStreamSample{
+		VIN: vin, Date: date, SourceEndpoint: strings.TrimSpace(env.SourceEndpoint),
+		EventID: env.StableEventID(), EventTime: eventTime, MassKG: mass,
+		TankCapacityLiters: tankCapacityLiters, PressureMPa: pressure, TemperatureC: temperature,
+		NoiseKG: noiseKG, RefuelThresholdKG: refuelThresholdKG,
+	}, "", true
+}
+
+func firstHydrogenNumber(fields map[string]any, keys []string) (float64, bool) {
+	for _, key := range keys {
+		if value, ok := telemetry.Number(fields, key); ok {
+			return value, true
+		}
+	}
+	return 0, false
+}
+
+func AppendHydrogenStream(ctx context.Context, exec Execer, env envelope.FrameEnvelope, loc *time.Location, now time.Time, tankCapacityLiters float64) (HydrogenStreamResult, error) {
+	sample, reason, ok := HydrogenStreamSampleFromEnvelope(env, loc, now, tankCapacityLiters)
+	if !ok {
+		result := HydrogenStreamResult{}
+		switch reason {
+		case "unsupported_protocol", "missing_pressure", "missing_temperature":
+			return result, nil
+		case "not_current_date":
+			result.NotCurrent = 1
+		default:
+			result.Invalid = 1
+		}
+		return result, nil
+	}
+	result := HydrogenStreamResult{Found: 1}
+	beginner, ok := exec.(txBeginner)
+	if !ok {
+		return result, sql.ErrTxDone
+	}
+	tx, err := beginner.BeginTx(ctx, nil)
+	if err != nil {
+		return result, err
+	}
+	defer tx.Rollback()
+	write, err := tx.ExecContext(ctx, upsertHydrogenStreamStateSQL,
+		sample.VIN, sample.Date, sample.SourceEndpoint, sample.MassKG, sample.MassKG, sample.MassKG,
+		sample.TankCapacityLiters, sample.PressureMPa, sample.PressureMPa,
+		sample.TemperatureC, sample.TemperatureC, sample.EventTime, sample.EventTime, sample.EventID,
+		sample.NoiseKG, defaultHydrogenMaxDropKG, sample.RefuelThresholdKG,
+		defaultHydrogenMaxDropKG, defaultHydrogenMaxDropKG, defaultHydrogenMaxDropKG,
+		sample.RefuelThresholdKG, sample.NoiseKG, defaultHydrogenMaxDropKG,
+	)
+	if err != nil {
+		return result, err
+	}
+	affected, _ := write.RowsAffected()
+	if affected == 0 {
+		result.Duplicate = 1
+		return result, tx.Commit()
+	}
+	if _, err := tx.ExecContext(ctx, projectHydrogenStreamDailySQL, sample.VIN, sample.Date); err != nil {
+		return result, err
+	}
+	if err := tx.Commit(); err != nil {
+		return result, err
+	}
+	result.Written = 1
+	return result, nil
+}
+
+const upsertHydrogenStreamStateSQL = `
+INSERT INTO vehicle_open_hydrogen_stream_state(
+  vin,stat_date,source_endpoint,first_mass_kg,last_mass_kg,cycle_min_mass_kg,consumption_kg,sample_count,
+  refuel_count,abnormal_drop_count,tank_capacity_l,first_pressure_mpa,last_pressure_mpa,
+  first_temperature_c,last_temperature_c,calculation_method,
+  first_event_time,last_event_time,last_event_id,quality_status,quality_reason
+) VALUES(?,?,?,?,?,?,0,1,0,0,?,?,?,?,?,'PRESSURE_NIST',?,?,?,'NO_DATA','有效压力质量样本不足2条')
+ON DUPLICATE KEY UPDATE
+  consumption_kg = consumption_kg + IF(VALUES(last_event_time)>last_event_time
+    AND cycle_min_mass_kg-VALUES(last_mass_kg)>? AND cycle_min_mass_kg-VALUES(last_mass_kg)<=?,
+    cycle_min_mass_kg-VALUES(last_mass_kg),0),
+  refuel_count = refuel_count + IF(VALUES(last_event_time)>last_event_time
+    AND VALUES(last_mass_kg)-cycle_min_mass_kg>?,1,0),
+  quality_status = IF(VALUES(last_event_time)<=last_event_time,quality_status,
+    IF(abnormal_drop_count+IF(cycle_min_mass_kg-VALUES(last_mass_kg)>?,1,0)>0,'SUSPECT','OK')),
+  quality_reason = IF(VALUES(last_event_time)<=last_event_time,quality_reason,
+    IF(abnormal_drop_count+IF(cycle_min_mass_kg-VALUES(last_mass_kg)>?,1,0)>0,'存在超过阈值的异常下降','')),
+  abnormal_drop_count = abnormal_drop_count + IF(VALUES(last_event_time)>last_event_time
+    AND cycle_min_mass_kg-VALUES(last_mass_kg)>?,1,0),
+  cycle_min_mass_kg = IF(VALUES(last_event_time)>last_event_time,
+    IF(VALUES(last_mass_kg)-cycle_min_mass_kg>?,VALUES(last_mass_kg),
+      IF(cycle_min_mass_kg-VALUES(last_mass_kg)>? AND cycle_min_mass_kg-VALUES(last_mass_kg)<=?,VALUES(last_mass_kg),cycle_min_mass_kg)),
+    cycle_min_mass_kg),
+  sample_count = sample_count + IF(VALUES(last_event_time)>last_event_time,1,0),
+  tank_capacity_l = IF(VALUES(last_event_time)>last_event_time,VALUES(tank_capacity_l),tank_capacity_l),
+  last_pressure_mpa = IF(VALUES(last_event_time)>last_event_time,VALUES(last_pressure_mpa),last_pressure_mpa),
+  last_temperature_c = IF(VALUES(last_event_time)>last_event_time,VALUES(last_temperature_c),last_temperature_c),
+  calculation_method = 'PRESSURE_NIST',
+  last_mass_kg = IF(VALUES(last_event_time)>last_event_time,VALUES(last_mass_kg),last_mass_kg),
+  last_event_id = IF(VALUES(last_event_time)>last_event_time,VALUES(last_event_id),last_event_id),
+  last_event_time = GREATEST(last_event_time,VALUES(last_event_time))`
+
+const projectHydrogenStreamDailySQL = `
+INSERT INTO vehicle_open_daily_energy(
+  vin,stat_date,energy_type,source_endpoint,consumption_kg,unit,first_mass_kg,last_mass_kg,
+  sample_count,refuel_count,quality_status,quality_reason,calculated_at
+)
+SELECT vin,stat_date,'HYDROGEN',source_endpoint,consumption_kg,'kg',first_mass_kg,last_mass_kg,
+       sample_count,refuel_count,quality_status,quality_reason,NOW(3)
+FROM vehicle_open_hydrogen_stream_state
+WHERE vin=? AND stat_date=?
+ORDER BY CASE quality_status WHEN 'OK' THEN 0 WHEN 'SUSPECT' THEN 1 ELSE 2 END,
+         sample_count DESC,source_endpoint ASC
+LIMIT 1
+ON DUPLICATE KEY UPDATE
+  source_endpoint=VALUES(source_endpoint),consumption_kg=VALUES(consumption_kg),unit='kg',
+  first_mass_kg=VALUES(first_mass_kg),last_mass_kg=VALUES(last_mass_kg),
+  sample_count=VALUES(sample_count),refuel_count=VALUES(refuel_count),
+  quality_status=VALUES(quality_status),quality_reason=VALUES(quality_reason),calculated_at=VALUES(calculated_at)`
--- a/go/vehicle-gateway/internal/stats/hydrogen_stream_test.go
+++ b/go/vehicle-gateway/internal/stats/hydrogen_stream_test.go
@@ -0,0 +1,138 @@
+package stats
+
+import (
+	"context"
+	"math"
+	"regexp"
+	"testing"
+	"time"
+
+	"github.com/DATA-DOG/go-sqlmock"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+func pressureEnvelope(at time.Time) envelope.FrameEnvelope {
+	return envelope.FrameEnvelope{
+		Protocol: envelope.ProtocolGB32960, VIN: "LA9GG64L0NBAF4175", EventID: "event-1",
+		EventTimeMS: at.UnixMilli(), SourceEndpoint: "10.0.0.1:9000",
+		Fields: map[string]any{
+			"gb32960.fuel_cell.max_hydrogen_pressure_mpa":  6.0,
+			"gb32960.fuel_cell.max_hydrogen_temperature_c": 44.0,
+			"gb32960.gd_fc_vehicle_info.hydrogen_mass_kg":  99.9,
+		},
+	}
+}
+
+func TestHydrogenStreamSampleUsesPressureTemperatureAndCapacity(t *testing.T) {
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	eventTime := time.Date(2026, 7, 21, 10, 30, 0, 0, loc)
+	sample, reason, ok := HydrogenStreamSampleFromEnvelope(pressureEnvelope(eventTime), loc, eventTime.Add(time.Minute), 2050)
+	if !ok || reason != "" {
+		t.Fatalf("sample rejected: reason=%q", reason)
+	}
+	if sample.Date != "2026-07-21" || sample.EventID != "event-1" || sample.TankCapacityLiters != 2050 {
+		t.Fatalf("unexpected sample: %#v", sample)
+	}
+	if math.Abs(sample.MassKG-9.092) > 0.01 {
+		t.Fatalf("pressure mass = %.3fkg, want about 9.092kg", sample.MassKG)
+	}
+	if sample.MassKG == 99.9 {
+		t.Fatal("reported Guangdong hydrogen mass must be ignored")
+	}
+
+	_, reason, ok = HydrogenStreamSampleFromEnvelope(pressureEnvelope(eventTime), loc, eventTime.AddDate(0, 0, 1), 2050)
+	if ok || reason != "not_current_date" {
+		t.Fatalf("historical sample accepted: ok=%v reason=%q", ok, reason)
+	}
+}
+
+func TestHydrogenStreamRejectsMissingCapacity(t *testing.T) {
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	eventTime := time.Date(2026, 7, 21, 10, 30, 0, 0, loc)
+	_, reason, ok := HydrogenStreamSampleFromEnvelope(pressureEnvelope(eventTime), loc, eventTime, 0)
+	if ok || reason != "missing_tank_capacity" {
+		t.Fatalf("missing capacity accepted: ok=%v reason=%q", ok, reason)
+	}
+}
+
+func TestNISTHydrogenDensityValidationPoint(t *testing.T) {
+	density, ok := HydrogenDensityKGPerM3(10, 26.85)
+	if !ok || math.Abs(density-7.625) > 0.01 {
+		t.Fatalf("density=%.6f ok=%v", density, ok)
+	}
+}
+
+func TestAppendHydrogenStreamPersistsPressureEvidenceAtomically(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	eventTime := time.Date(2026, 7, 21, 10, 30, 0, 0, loc)
+	mock.ExpectBegin()
+	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_hydrogen_stream_state")).
+		WithArgs("LA9GG64L0NBAF4175", "2026-07-21", "10.0.0.1:9000", sqlmock.AnyArg(), sqlmock.AnyArg(), sqlmock.AnyArg(),
+			2050.0, 6.0, 6.0, 44.0, 44.0, eventTime, eventTime, "event-1",
+			sqlmock.AnyArg(), 20.0, sqlmock.AnyArg(), 20.0, 20.0, 20.0,
+			sqlmock.AnyArg(), sqlmock.AnyArg(), 20.0).
+		WillReturnResult(sqlmock.NewResult(1, 1))
+	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_daily_energy")).
+		WithArgs("LA9GG64L0NBAF4175", "2026-07-21").
+		WillReturnResult(sqlmock.NewResult(1, 1))
+	mock.ExpectCommit()
+
+	result, err := AppendHydrogenStream(context.Background(), db, pressureEnvelope(eventTime), loc, eventTime, 2050)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.Found != 1 || result.Written != 1 {
+		t.Fatalf("unexpected result: %#v", result)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestWriterAppendWithResultUsesInMemoryCapacity(t *testing.T) {
+	db, mock, err := sqlmock.New()
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+	loc := time.FixedZone("Asia/Shanghai", 8*3600)
+	eventTime := time.Now().In(loc).Truncate(time.Millisecond)
+	mock.ExpectBegin()
+	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_hydrogen_stream_state")).WillReturnResult(sqlmock.NewResult(1, 1))
+	mock.ExpectExec(regexp.QuoteMeta("INSERT INTO vehicle_open_daily_energy")).WillReturnResult(sqlmock.NewResult(1, 1))
+	mock.ExpectCommit()
+
+	writer := NewWriter(db, loc)
+	writer.hydrogenTankCapacities["LA9GG64L0NBAF4175"] = 2050
+	result, err := writer.AppendWithResult(context.Background(), pressureEnvelope(eventTime))
+	if err != nil {
+		t.Fatalf("AppendWithResult() error = %v", err)
+	}
+	if result.HydrogenSamplesFound != 1 || result.HydrogenSamplesWritten != 1 {
+		t.Fatalf("hydrogen counters lost: %+v", result)
+	}
+	if err := mock.ExpectationsWereMet(); err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestHydrogenStreamSQLGuardsDuplicatesAndRecordsPressure(t *testing.T) {
+	for _, want := range []string{
+		"VALUES(last_event_time)>last_event_time",
+		"cycle_min_mass_kg-VALUES(last_mass_kg)>?",
+		"tank_capacity_l",
+		"last_pressure_mpa",
+		"last_temperature_c",
+		"PRESSURE_NIST",
+	} {
+		if !regexp.MustCompile(regexp.QuoteMeta(want)).MatchString(upsertHydrogenStreamStateSQL) {
+			t.Fatalf("stream upsert missing %q", want)
+		}
+	}
+}
--- a/go/vehicle-gateway/internal/stats/pure_hydrogen.go
+++ b/go/vehicle-gateway/internal/stats/pure_hydrogen.go
@@ -0,0 +1,120 @@
+package stats
+
+import (
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+const (
+	gb32960FuelCellEngineWorkMode = 2
+	yutongFuelCellRunningMode     = 4
+	yutongFuelCellDrivingMode     = 11
+)
+
+// PureHydrogenModeFromEnvelope returns whether the reported vehicle is in a
+// fuel-cell-only work mode and whether the source value is understood.
+//
+// The 32960 fuel-cell extension reports engine_work_state; production frames
+// use mode 2 for normal fuel-cell operation. Yutong reports the equivalent
+// state through TRIANGLE_STATE; production frames use 1 for inactive and 4/11
+// for active fuel-cell operating modes.
+func PureHydrogenModeFromEnvelope(env envelope.FrameEnvelope) (active bool, known bool) {
+	value, exists := env.Fields[envelope.FieldFuelCellWorkMode]
+	if !exists {
+		return false, false
+	}
+	mode, ok := integerMode(value)
+	if !ok {
+		return false, false
+	}
+	switch env.Protocol {
+	case envelope.ProtocolGB32960:
+		switch mode {
+		case gb32960FuelCellEngineWorkMode:
+			return true, true
+		case 0, 1:
+			return false, true
+		default:
+			return false, false
+		}
+	case envelope.ProtocolYutongMQTT:
+		switch mode {
+		case yutongFuelCellRunningMode, yutongFuelCellDrivingMode:
+			return true, true
+		case 1:
+			return false, true
+		default:
+			return false, false
+		}
+	default:
+		return false, false
+	}
+}
+
+// PureHydrogenMileageDelta returns the odometer delta that can be attributed
+// to pure-hydrogen operation. Both endpoints must report a known active mode;
+// this deliberately leaves transitions and missing mode data unclassified.
+func PureHydrogenMileageDelta(
+	previousKM float64,
+	currentKM float64,
+	previousActive bool,
+	previousKnown bool,
+	currentActive bool,
+	currentKnown bool,
+) float64 {
+	delta := currentKM - previousKM
+	if !previousKnown || !previousActive || !currentKnown || !currentActive {
+		return 0
+	}
+	if delta < 0 || delta > maxSelectedDailyMileageKM {
+		return 0
+	}
+	return delta
+}
+
+func integerMode(value any) (int, bool) {
+	switch typed := value.(type) {
+	case json.Number:
+		parsed, err := strconv.Atoi(typed.String())
+		return parsed, err == nil
+	case string:
+		parsed, err := strconv.Atoi(strings.TrimSpace(typed))
+		return parsed, err == nil
+	case int:
+		return typed, true
+	case int8:
+		return int(typed), true
+	case int16:
+		return int(typed), true
+	case int32:
+		return int(typed), true
+	case int64:
+		return int(typed), true
+	case uint:
+		return int(typed), true
+	case uint8:
+		return int(typed), true
+	case uint16:
+		return int(typed), true
+	case uint32:
+		return int(typed), true
+	case uint64:
+		if typed > uint64(^uint(0)>>1) {
+			return 0, false
+		}
+		return int(typed), true
+	case float32:
+		parsed := int(typed)
+		return parsed, float32(parsed) == typed
+	case float64:
+		parsed := int(typed)
+		return parsed, float64(parsed) == typed
+	default:
+		parsed, err := strconv.Atoi(strings.TrimSpace(fmt.Sprint(value)))
+		return parsed, err == nil
+	}
+}
--- a/go/vehicle-gateway/internal/stats/pure_hydrogen_test.go
+++ b/go/vehicle-gateway/internal/stats/pure_hydrogen_test.go
@@ -0,0 +1,134 @@
+package stats
+
+import (
+	"encoding/json"
+	"testing"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+func TestPureHydrogenModeFromEnvelope(t *testing.T) {
+	tests := []struct {
+		name   string
+		env    envelope.FrameEnvelope
+		active bool
+		known  bool
+	}{
+		{
+			name:   "gb32960 fuel cell mode",
+			env:    envelope.FrameEnvelope{Protocol: envelope.ProtocolGB32960, Fields: map[string]any{envelope.FieldFuelCellWorkMode: 2}},
+			active: true,
+			known:  true,
+		},
+		{
+			name:  "gb32960 electric mode",
+			env:   envelope.FrameEnvelope{Protocol: envelope.ProtocolGB32960, Fields: map[string]any{envelope.FieldFuelCellWorkMode: 1}},
+			known: true,
+		},
+		{
+			name:   "yutong active mode",
+			env:    envelope.FrameEnvelope{Protocol: envelope.ProtocolYutongMQTT, Fields: map[string]any{envelope.FieldFuelCellWorkMode: json.Number("4")}},
+			active: true,
+			known:  true,
+		},
+		{
+			name:   "yutong driving mode",
+			env:    envelope.FrameEnvelope{Protocol: envelope.ProtocolYutongMQTT, Fields: map[string]any{envelope.FieldFuelCellWorkMode: "11"}},
+			active: true,
+			known:  true,
+		},
+		{
+			name:  "yutong inactive mode",
+			env:   envelope.FrameEnvelope{Protocol: envelope.ProtocolYutongMQTT, Fields: map[string]any{envelope.FieldFuelCellWorkMode: float64(1)}},
+			known: true,
+		},
+		{
+			name: "unknown yutong mode",
+			env:  envelope.FrameEnvelope{Protocol: envelope.ProtocolYutongMQTT, Fields: map[string]any{envelope.FieldFuelCellWorkMode: 9}},
+		},
+		{
+			name: "unsupported protocol",
+			env:  envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, Fields: map[string]any{envelope.FieldFuelCellWorkMode: 3}},
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			active, known := PureHydrogenModeFromEnvelope(test.env)
+			if active != test.active || known != test.known {
+				t.Fatalf("PureHydrogenModeFromEnvelope() = (%v, %v), want (%v, %v)", active, known, test.active, test.known)
+			}
+		})
+	}
+}
+
+func TestPureHydrogenMileageDeltaRequiresContinuousKnownActiveMode(t *testing.T) {
+	tests := []struct {
+		name                          string
+		previousKM, currentKM         float64
+		previousActive, previousKnown bool
+		currentActive, currentKnown   bool
+		want                          float64
+	}{
+		{
+			name:           "continuous active interval",
+			previousKM:     100,
+			currentKM:      106.5,
+			previousActive: true,
+			previousKnown:  true,
+			currentActive:  true,
+			currentKnown:   true,
+			want:           6.5,
+		},
+		{
+			name:          "transition into active is unclassified",
+			previousKM:    100,
+			currentKM:     106.5,
+			previousKnown: true,
+			currentActive: true,
+			currentKnown:  true,
+		},
+		{
+			name:           "unknown endpoint is unclassified",
+			previousKM:     100,
+			currentKM:      106.5,
+			previousActive: true,
+			previousKnown:  true,
+			currentActive:  true,
+		},
+		{
+			name:           "odometer rollback is rejected",
+			previousKM:     106.5,
+			currentKM:      100,
+			previousActive: true,
+			previousKnown:  true,
+			currentActive:  true,
+			currentKnown:   true,
+		},
+		{
+			name:           "implausible jump is rejected",
+			previousKM:     100,
+			currentKM:      2601,
+			previousActive: true,
+			previousKnown:  true,
+			currentActive:  true,
+			currentKnown:   true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			got := PureHydrogenMileageDelta(
+				test.previousKM,
+				test.currentKM,
+				test.previousActive,
+				test.previousKnown,
+				test.currentActive,
+				test.currentKnown,
+			)
+			if got != test.want {
+				t.Fatalf("PureHydrogenMileageDelta() = %v, want %v", got, test.want)
+			}
+		})
+	}
+}
--- a/go/vehicle-gateway/internal/stats/query.go
+++ b/go/vehicle-gateway/internal/stats/query.go
@@ -58,48 +58,51 @@ type MetricDiagnosisQuery struct {
 }

 type MetricRow struct {
-	VIN                  string   `json:"vin"`
-	StatDate             string   `json:"stat_date"`
-	Protocol             string   `json:"protocol"`
-	SourceID             *int64   `json:"source_id,omitempty"`
-	SourceIP             string   `json:"source_ip,omitempty"`
-	LatestSourceEndpoint string   `json:"latest_source_endpoint,omitempty"`
-	PlatformName         string   `json:"platform_name,omitempty"`
-	SourceCode           string   `json:"source_code,omitempty"`
-	SourceKind           string   `json:"source_kind,omitempty"`
-	DailyMileageKM       float64  `json:"daily_mileage_km"`
-	LatestTotalMileageKM *float64 `json:"latest_total_mileage_km,omitempty"`
-	UpdatedAt            string   `json:"updated_at"`
+	VIN                   string   `json:"vin"`
+	StatDate              string   `json:"stat_date"`
+	Protocol              string   `json:"protocol"`
+	SourceID              *int64   `json:"source_id,omitempty"`
+	SourceIP              string   `json:"source_ip,omitempty"`
+	LatestSourceEndpoint  string   `json:"latest_source_endpoint,omitempty"`
+	PlatformName          string   `json:"platform_name,omitempty"`
+	SourceCode            string   `json:"source_code,omitempty"`
+	SourceKind            string   `json:"source_kind,omitempty"`
+	DailyMileageKM        float64  `json:"daily_mileage_km"`
+	PureHydrogenMileageKM float64  `json:"pure_hydrogen_mileage_km"`
+	LatestTotalMileageKM  *float64 `json:"latest_total_mileage_km,omitempty"`
+	UpdatedAt             string   `json:"updated_at"`
 }

 type MetricSourceRow struct {
-	VIN                  string   `json:"vin"`
-	StatDate             string   `json:"stat_date"`
-	Protocol             string   `json:"protocol"`
-	SourceKey            string   `json:"source_key"`
-	SourceIP             string   `json:"source_ip"`
-	SourceEndpoint       string   `json:"source_endpoint,omitempty"`
-	Phone                string   `json:"phone,omitempty"`
-	DeviceID             string   `json:"device_id,omitempty"`
-	PlatformName         string   `json:"platform_name,omitempty"`
-	SourceID             *int64   `json:"source_id,omitempty"`
-	SourceCode           string   `json:"source_code,omitempty"`
-	SourceKind           string   `json:"source_kind,omitempty"`
-	SourceEnabled        *bool    `json:"source_enabled,omitempty"`
-	TrustPriority        *int     `json:"trust_priority,omitempty"`
-	FirstTotalMileageKM  *float64 `json:"first_total_mileage_km,omitempty"`
-	LatestTotalMileageKM *float64 `json:"latest_total_mileage_km,omitempty"`
-	DailyMileageKM       float64  `json:"daily_mileage_km"`
-	SampleCount          int64    `json:"sample_count"`
-	FirstEventTime       string   `json:"first_event_time,omitempty"`
-	LatestEventTime      string   `json:"latest_event_time,omitempty"`
-	QualityStatus        string   `json:"quality_status"`
-	QualityReason        string   `json:"quality_reason,omitempty"`
-	IsSelected           bool     `json:"is_selected"`
-	SelectionStatus      string   `json:"selection_status,omitempty"`
-	SelectionReason      string   `json:"selection_reason,omitempty"`
-	SelectionAction      string   `json:"selection_action,omitempty"`
-	UpdatedAt            string   `json:"updated_at"`
+	VIN                     string   `json:"vin"`
+	StatDate                string   `json:"stat_date"`
+	Protocol                string   `json:"protocol"`
+	SourceKey               string   `json:"source_key"`
+	SourceIP                string   `json:"source_ip"`
+	SourceEndpoint          string   `json:"source_endpoint,omitempty"`
+	Phone                   string   `json:"phone,omitempty"`
+	DeviceID                string   `json:"device_id,omitempty"`
+	PlatformName            string   `json:"platform_name,omitempty"`
+	SourceID                *int64   `json:"source_id,omitempty"`
+	SourceCode              string   `json:"source_code,omitempty"`
+	SourceKind              string   `json:"source_kind,omitempty"`
+	SourceEnabled           *bool    `json:"source_enabled,omitempty"`
+	TrustPriority           *int     `json:"trust_priority,omitempty"`
+	FirstTotalMileageKM     *float64 `json:"first_total_mileage_km,omitempty"`
+	LatestTotalMileageKM    *float64 `json:"latest_total_mileage_km,omitempty"`
+	DailyMileageKM          float64  `json:"daily_mileage_km"`
+	PureHydrogenMileageKM   float64  `json:"pure_hydrogen_mileage_km"`
+	PureHydrogenSampleCount int64    `json:"pure_hydrogen_sample_count"`
+	SampleCount             int64    `json:"sample_count"`
+	FirstEventTime          string   `json:"first_event_time,omitempty"`
+	LatestEventTime         string   `json:"latest_event_time,omitempty"`
+	QualityStatus           string   `json:"quality_status"`
+	QualityReason           string   `json:"quality_reason,omitempty"`
+	IsSelected              bool     `json:"is_selected"`
+	SelectionStatus         string   `json:"selection_status,omitempty"`
+	SelectionReason         string   `json:"selection_reason,omitempty"`
+	SelectionAction         string   `json:"selection_action,omitempty"`
+	UpdatedAt               string   `json:"updated_at"`
 }

 type MetricDiagnosisRow struct {
@@ -241,6 +244,7 @@ func (r *MetricRepository) Query(ctx context.Context, query MetricQuery) ([]Metr
 			&sourceCode,
 			&sourceKind,
 			&row.DailyMileageKM,
+			&row.PureHydrogenMileageKM,
 			&latest,
 			&updatedAt,
 		); err != nil {
@@ -303,7 +307,9 @@ func (r *MetricRepository) QuerySources(ctx context.Context, query MetricSourceQ
 			&firstTotal,
 			&latestTotal,
 			&row.DailyMileageKM,
+			&row.PureHydrogenMileageKM,
 			&row.SampleCount,
+			&row.PureHydrogenSampleCount,
 			&firstEvent,
 			&latestEvent,
 			&row.QualityStatus,
@@ -1108,7 +1114,7 @@ func buildMetricSQL(query MetricQuery) (string, []any) {
 	where, args := buildMetricWhere(query)
 	sqlText := `SELECT m.vin, m.stat_date, m.protocol, m.source_id,
       ds.source_ip, ds.latest_source_endpoint, ds.platform_name, ds.source_code, ds.source_kind,
-       m.daily_mileage_km, m.latest_total_mileage_km, m.updated_at
+       m.daily_mileage_km, m.pure_hydrogen_mileage_km, m.latest_total_mileage_km, m.updated_at
 FROM vehicle_daily_mileage m
 LEFT JOIN vehicle_data_source ds ON ds.id = m.source_id`
 	if len(where) > 0 {
@@ -1124,7 +1130,8 @@ func buildMetricSourceSQL(query MetricSourceQuery) (string, []any) {
 	sqlText := `SELECT s.vin, s.stat_date, s.protocol, s.source_key, s.source_ip, s.source_endpoint, s.phone, s.device_id,
       COALESCE(NULLIF(TRIM(s.platform_name), ''), ds.platform_name) AS platform_name,
       ds.id, ds.source_code, ` + metricSourceKindSQL("s") + ` AS source_kind, ds.enabled, ds.trust_priority,
-       s.first_total_mileage_km, s.latest_total_mileage_km, s.daily_mileage_km, s.sample_count,
+       s.first_total_mileage_km, s.latest_total_mileage_km, s.daily_mileage_km, s.pure_hydrogen_mileage_km,
+       s.sample_count, s.pure_hydrogen_sample_count,
       s.first_event_time, s.latest_event_time, s.quality_status, s.quality_reason, s.is_selected, s.updated_at
 FROM vehicle_daily_mileage_source s
 LEFT JOIN vehicle_data_source ds ON ds.protocol = s.protocol AND ds.source_ip = s.source_ip`
--- a/go/vehicle-gateway/internal/stats/query_test.go
+++ b/go/vehicle-gateway/internal/stats/query_test.go
@@ -32,10 +32,10 @@ func TestMetricRepositoryQueriesDailyMetricsWithFilters(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_id",
 			"source_ip", "latest_source_endpoint", "platform_name", "source_code", "source_kind", "daily_mileage_km",
-			"latest_total_mileage_km", "updated_at",
+			"pure_hydrogen_mileage_km", "latest_total_mileage_km", "updated_at",
 		}).AddRow(
 			"LKLG7C4E3NA774736", time.Date(2026, 7, 1, 0, 0, 0, 0, time.FixedZone("Asia/Shanghai", 8*3600)), "JT808", 3,
-			"115.231.168.135", "115.231.168.135:41561", "G7 平台", "G7S", "PLATFORM", 12.3,
+			"115.231.168.135", "115.231.168.135:41561", "G7 平台", "G7S", "PLATFORM", 12.3, 0.0,
 			12357.9, time.Date(2026, 7, 1, 23, 9, 36, 0, time.FixedZone("Asia/Shanghai", 8*3600)),
 		))

@@ -80,10 +80,10 @@ func TestMetricQueryReturnsSelectedSourceID(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_id",
 			"source_ip", "latest_source_endpoint", "platform_name", "source_code", "source_kind", "daily_mileage_km",
-			"latest_total_mileage_km", "updated_at",
+			"pure_hydrogen_mileage_km", "latest_total_mileage_km", "updated_at",
 		}).AddRow(
 			"LA9GG64L7PBAF4001", "2026-07-08", "JT808", 2,
-			"117.132.194.31", "117.132.194.31:20471", "广安北斗", "guangan_beidou", "PLATFORM", 23.1,
+			"117.132.194.31", "117.132.194.31:20471", "广安北斗", "guangan_beidou", "PLATFORM", 23.1, 0.0,
 			4123.9, "2026-07-08 13:30:57",
 		))

@@ -115,13 +115,13 @@ func TestMetricRepositoryQueriesDailyMetricSourcesWithEvidence(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_key", "source_ip", "source_endpoint", "phone", "device_id",
 			"platform_name", "source_id", "source_code", "source_kind", "enabled", "trust_priority",
-			"first_total_mileage_km", "latest_total_mileage_km", "daily_mileage_km", "sample_count",
+			"first_total_mileage_km", "latest_total_mileage_km", "daily_mileage_km", "pure_hydrogen_mileage_km", "sample_count", "pure_hydrogen_sample_count",
 			"first_event_time", "latest_event_time", "quality_status", "quality_reason", "is_selected", "updated_at",
 		}).AddRow(
 			"LA9GG64L7PBAF4001", "2026-07-08", "JT808", "JT808:13307795425@115.231.168.135", "115.231.168.135",
 			"115.231.168.135:41561", "13307795425", nil,
 			"信达", 5, "xinda", "PLATFORM", 1, 10,
-			4100.8, 4123.9, 23.1, 128,
+			4100.8, 4123.9, 23.1, 18.6, 128, 96,
 			"2026-07-08 00:01:00", "2026-07-08 23:59:00", "OK", "historical_source_baseline", 1, "2026-07-08 23:59:10",
 		))

@@ -856,10 +856,10 @@ func TestMetricHandlerReturnsDailyMetrics(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_id",
 			"source_ip", "latest_source_endpoint", "platform_name", "source_code", "source_kind", "daily_mileage_km",
-			"latest_total_mileage_km", "updated_at",
+			"pure_hydrogen_mileage_km", "latest_total_mileage_km", "updated_at",
 		}).AddRow(
 			"LB9A32A21R0LS1707", "2020-07-01", "GB32960", 1,
-			"8.134.95.166", "8.134.95.166:32960", "现代 HTWO", "HYUNDAI", "PLATFORM", 0.0,
+			"8.134.95.166", "8.134.95.166:32960", "现代 HTWO", "HYUNDAI", "PLATFORM", 0.0, 0.0,
 			53490.9, "2026-07-01 22:28:25",
 		))

@@ -900,13 +900,13 @@ func TestMetricHandlerReturnsDailyMetricSources(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_key", "source_ip", "source_endpoint", "phone", "device_id",
 			"platform_name", "source_id", "source_code", "source_kind", "enabled", "trust_priority",
-			"first_total_mileage_km", "latest_total_mileage_km", "daily_mileage_km", "sample_count",
+			"first_total_mileage_km", "latest_total_mileage_km", "daily_mileage_km", "pure_hydrogen_mileage_km", "sample_count", "pure_hydrogen_sample_count",
 			"first_event_time", "latest_event_time", "quality_status", "quality_reason", "is_selected", "updated_at",
 		}).AddRow(
 			"LA9GG64L7PBAF4001", "2026-07-08", "JT808", "JT808:13307795425@115.231.168.135", "115.231.168.135",
 			"115.231.168.135:41561", "13307795425", nil,
 			"信达", 5, "xinda", "PLATFORM", 1, 10,
-			4100.8, 4123.9, 23.1, 128,
+			4100.8, 4123.9, 23.1, 18.6, 128, 96,
 			"2026-07-08 00:01:00", "2026-07-08 23:59:00", "OK", "historical_source_baseline", 1, "2026-07-08 23:59:10",
 		))

@@ -1340,7 +1340,7 @@ func TestMetricHandlerReturnsEmptyItemsArrayWhenNoRows(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_id",
 			"source_ip", "latest_source_endpoint", "platform_name", "source_code", "source_kind", "daily_mileage_km",
-			"latest_total_mileage_km", "updated_at",
+			"pure_hydrogen_mileage_km", "latest_total_mileage_km", "updated_at",
 		}))

 	handler := NewMetricHandler(NewMetricRepository(db))
@@ -1372,10 +1372,10 @@ func TestMetricHandlerSkipsTotalCountByDefault(t *testing.T) {
 		WillReturnRows(sqlmock.NewRows([]string{
 			"vin", "stat_date", "protocol", "source_id",
 			"source_ip", "latest_source_endpoint", "platform_name", "source_code", "source_kind", "daily_mileage_km",
-			"latest_total_mileage_km", "updated_at",
+			"pure_hydrogen_mileage_km", "latest_total_mileage_km", "updated_at",
 		}).AddRow(
 			"LKLG7C4E3NA774736", "2026-07-02", "JT808", 3,
-			"115.231.168.135", "115.231.168.135:41561", "G7 平台", "G7S", "PLATFORM", 12.3,
+			"115.231.168.135", "115.231.168.135:41561", "G7 平台", "G7S", "PLATFORM", 12.3, 0.0,
 			8805.1, "2026-07-02 23:59:59",
 		))

--- a/go/vehicle-gateway/internal/stats/schema.go
+++ b/go/vehicle-gateway/internal/stats/schema.go
@@ -6,6 +6,7 @@ const DailyMileageTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_daily_mileage (
  protocol VARCHAR(32) NOT NULL,
  source_id BIGINT NULL,
  daily_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0,
+  pure_hydrogen_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0,
  latest_total_mileage_km DECIMAL(18,3) NULL,
  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
  PRIMARY KEY (vin, stat_date, protocol),
@@ -20,6 +21,7 @@ var DailyMileageAlterSQL = []string{
 	"ALTER TABLE vehicle_data_source ADD KEY idx_protocol_source_code (protocol, source_code)",
 	"ALTER TABLE vehicle_data_source ADD KEY idx_protocol_source_kind_seen (protocol, source_kind, latest_seen_at)",
 	"ALTER TABLE vehicle_daily_mileage ADD COLUMN source_id BIGINT NULL AFTER protocol",
+	"ALTER TABLE vehicle_daily_mileage ADD COLUMN pure_hydrogen_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0 AFTER daily_mileage_km",
 	"ALTER TABLE vehicle_daily_mileage ADD KEY idx_source_id (source_id)",
 	"ALTER TABLE vehicle_daily_mileage DROP COLUMN first_total_mileage_km",
 	"ALTER TABLE vehicle_daily_mileage DROP COLUMN trusted_source_key",
@@ -30,6 +32,10 @@ var DailyMileageAlterSQL = []string{
 	"ALTER TABLE vehicle_daily_mileage_source ADD KEY idx_protocol_date_quality (protocol, stat_date, quality_status, vin)",
 	"ALTER TABLE vehicle_daily_mileage_source ADD KEY idx_protocol_date_quality_reason (protocol, stat_date, quality_status, quality_reason, vin)",
 	"ALTER TABLE vehicle_daily_mileage_source ADD KEY idx_source_ip_date (protocol, source_ip, stat_date)",
+	"ALTER TABLE vehicle_daily_mileage_source ADD COLUMN pure_hydrogen_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0 AFTER daily_mileage_km",
+	"ALTER TABLE vehicle_daily_mileage_source ADD COLUMN pure_hydrogen_sample_count BIGINT NOT NULL DEFAULT 0 AFTER sample_count",
+	"ALTER TABLE vehicle_daily_mileage_source ADD COLUMN latest_pure_hydrogen_active TINYINT(1) NOT NULL DEFAULT 0 AFTER latest_event_time",
+	"ALTER TABLE vehicle_daily_mileage_source ADD COLUMN latest_pure_hydrogen_mode_known TINYINT(1) NOT NULL DEFAULT 0 AFTER latest_pure_hydrogen_active",
 }

 const DataSourceTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_data_source (
@@ -67,9 +73,13 @@ const DailyMileageSourceTableSQL = `CREATE TABLE IF NOT EXISTS vehicle_daily_mil
  first_total_mileage_km DECIMAL(18,3) NULL,
  latest_total_mileage_km DECIMAL(18,3) NULL,
  daily_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0,
+  pure_hydrogen_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0,
  sample_count BIGINT NOT NULL DEFAULT 0,
+  pure_hydrogen_sample_count BIGINT NOT NULL DEFAULT 0,
  first_event_time DATETIME NULL,
  latest_event_time DATETIME NULL,
+  latest_pure_hydrogen_active TINYINT(1) NOT NULL DEFAULT 0,
+  latest_pure_hydrogen_mode_known TINYINT(1) NOT NULL DEFAULT 0,
  quality_status VARCHAR(32) NOT NULL DEFAULT 'OK',
  quality_reason VARCHAR(255) NULL,
  is_selected TINYINT(1) NOT NULL DEFAULT 0,
--- a/go/vehicle-gateway/internal/stats/source_mileage.go
+++ b/go/vehicle-gateway/internal/stats/source_mileage.go
@@ -24,23 +24,27 @@ const (
 )

 type SourceMileageSample struct {
-	VIN             string
-	StatDate        string
-	Protocol        envelope.Protocol
-	SourceKey       string
-	SourceIP        string
-	SourceEndpoint  string
-	Phone           string
-	DeviceID        string
-	PlatformName    string
-	FirstTotalKM    float64
-	LatestTotalKM   float64
-	DailyKM         float64
-	SampleCount     int64
-	FirstEventTime  time.Time
-	LatestEventTime time.Time
-	QualityStatus   string
-	QualityReason   string
+	VIN                         string
+	StatDate                    string
+	Protocol                    envelope.Protocol
+	SourceKey                   string
+	SourceIP                    string
+	SourceEndpoint              string
+	Phone                       string
+	DeviceID                    string
+	PlatformName                string
+	FirstTotalKM                float64
+	LatestTotalKM               float64
+	DailyKM                     float64
+	PureHydrogenMileageKM       float64
+	SampleCount                 int64
+	PureHydrogenSampleCount     int64
+	FirstEventTime              time.Time
+	LatestEventTime             time.Time
+	LatestPureHydrogenActive    bool
+	LatestPureHydrogenModeKnown bool
+	QualityStatus               string
+	QualityReason               string
 }

 func SourceKey(protocol envelope.Protocol, phone string, deviceID string, sourceIP string) string {
@@ -80,26 +84,37 @@ func SourceKeyForSource(protocol envelope.Protocol, phone string, deviceID strin
 func SourceMileageSampleFromMetric(sample MetricSample, identity SourceIdentity) SourceMileageSample {
 	eventTime := sample.EventTime
 	return SourceMileageSample{
-		VIN:             sample.VIN,
-		StatDate:        sample.StatDate,
-		Protocol:        sample.Protocol,
-		SourceKey:       SourceKeyForSource(sample.Protocol, sample.Phone, sample.DeviceID, identity.SourceIP, identity.SourceKind, identity.SourceCode),
-		SourceIP:        identity.SourceIP,
-		SourceEndpoint:  identity.SourceEndpoint,
-		Phone:           sample.Phone,
-		DeviceID:        sample.DeviceID,
-		PlatformName:    firstNonEmpty(sample.PlatformName, identity.PlatformName),
-		FirstTotalKM:    sample.TotalMileageKM,
-		LatestTotalKM:   sample.TotalMileageKM,
-		DailyKM:         0,
-		SampleCount:     1,
-		FirstEventTime:  eventTime,
-		LatestEventTime: eventTime,
-		QualityStatus:   QualityOK,
-		QualityReason:   "realtime_sample",
+		VIN:                         sample.VIN,
+		StatDate:                    sample.StatDate,
+		Protocol:                    sample.Protocol,
+		SourceKey:                   SourceKeyForSource(sample.Protocol, sample.Phone, sample.DeviceID, identity.SourceIP, identity.SourceKind, identity.SourceCode),
+		SourceIP:                    identity.SourceIP,
+		SourceEndpoint:              identity.SourceEndpoint,
+		Phone:                       sample.Phone,
+		DeviceID:                    sample.DeviceID,
+		PlatformName:                firstNonEmpty(sample.PlatformName, identity.PlatformName),
+		FirstTotalKM:                sample.TotalMileageKM,
+		LatestTotalKM:               sample.TotalMileageKM,
+		DailyKM:                     0,
+		PureHydrogenMileageKM:       0,
+		SampleCount:                 1,
+		PureHydrogenSampleCount:     boolCount(sample.PureHydrogenActive && sample.PureHydrogenModeKnown),
+		FirstEventTime:              eventTime,
+		LatestEventTime:             eventTime,
+		LatestPureHydrogenActive:    sample.PureHydrogenActive,
+		LatestPureHydrogenModeKnown: sample.PureHydrogenModeKnown,
+		QualityStatus:               QualityOK,
+		QualityReason:               "realtime_sample",
 	}
 }

+func boolCount(value bool) int64 {
+	if value {
+		return 1
+	}
+	return 0
+}
+
 func firstNonEmpty(values ...string) string {
 	for _, value := range values {
 		value = strings.TrimSpace(value)
@@ -203,9 +218,13 @@ func UpsertSourceMileage(ctx context.Context, exec Execer, sample SourceMileageS
 		sample.FirstTotalKM,
 		sample.LatestTotalKM,
 		sample.DailyKM,
+		sample.PureHydrogenMileageKM,
 		sample.SampleCount,
+		sample.PureHydrogenSampleCount,
 		sample.FirstEventTime,
 		sample.LatestEventTime,
+		sample.LatestPureHydrogenActive,
+		sample.LatestPureHydrogenModeKnown,
 		sample.QualityStatus,
 		sample.QualityReason,
 	)
@@ -422,18 +441,44 @@ const normalizePlatformMaxMileageSQL = `(` + normalizePlatformQualityWindowDaysS

 const normalizePlatformOutsideDailyRangeSQL = `(` + normalizePlatformDailySQL + ` < 0 OR ` + normalizePlatformDailySQL + ` > ` + normalizePlatformMaxMileageSQL + `)`

+const upsertSourcePureHydrogenIncrementSQL = `CASE
+    WHEN latest_event_time IS NOT NULL
+     AND VALUES(latest_event_time) > latest_event_time
+     AND latest_pure_hydrogen_mode_known = 1
+     AND latest_pure_hydrogen_active = 1
+     AND VALUES(latest_pure_hydrogen_mode_known) = 1
+     AND VALUES(latest_pure_hydrogen_active) = 1
+     AND VALUES(latest_total_mileage_km) >= latest_total_mileage_km
+     AND VALUES(latest_total_mileage_km) - latest_total_mileage_km <= ` + maxSelectedDailyMileageKMSQL + `
+      THEN VALUES(latest_total_mileage_km) - latest_total_mileage_km
+    ELSE 0
+  END`
+
 const upsertSourceMileageSQL = `
 INSERT INTO vehicle_daily_mileage_source
  (vin, stat_date, protocol, source_key, source_ip, source_endpoint, phone, device_id, platform_name,
-   first_total_mileage_km, latest_total_mileage_km, daily_mileage_km, sample_count,
-   first_event_time, latest_event_time, quality_status, quality_reason)
-VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+   first_total_mileage_km, latest_total_mileage_km, daily_mileage_km, pure_hydrogen_mileage_km,
+   sample_count, pure_hydrogen_sample_count, first_event_time, latest_event_time,
+   latest_pure_hydrogen_active, latest_pure_hydrogen_mode_known, quality_status, quality_reason)
+VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 	ON DUPLICATE KEY UPDATE
 	  source_ip = VALUES(source_ip),
 	  source_endpoint = VALUES(source_endpoint),
 	  phone = VALUES(phone),
 	  device_id = VALUES(device_id),
 	  platform_name = COALESCE(NULLIF(TRIM(VALUES(platform_name)), ''), platform_name),
+	  pure_hydrogen_mileage_km = pure_hydrogen_mileage_km + ` + upsertSourcePureHydrogenIncrementSQL + `,
+	  pure_hydrogen_sample_count = pure_hydrogen_sample_count + VALUES(pure_hydrogen_sample_count),
+	  latest_pure_hydrogen_active = CASE
+	    WHEN latest_event_time IS NULL OR VALUES(latest_event_time) >= latest_event_time
+	      THEN VALUES(latest_pure_hydrogen_active)
+	    ELSE latest_pure_hydrogen_active
+	  END,
+	  latest_pure_hydrogen_mode_known = CASE
+	    WHEN latest_event_time IS NULL OR VALUES(latest_event_time) >= latest_event_time
+	      THEN VALUES(latest_pure_hydrogen_mode_known)
+	    ELSE latest_pure_hydrogen_mode_known
+	  END,
 	  first_total_mileage_km = ` + upsertSourceMergedFirstTotalSQL + `,
 	  latest_total_mileage_km = ` + upsertSourceMergedLatestTotalSQL + `,
 	  daily_mileage_km = ` + upsertSourceMergedDailySQL + `,
@@ -456,8 +501,9 @@ VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
 const normalizePlatformSourceMileageInsertSQL = `
 INSERT INTO vehicle_daily_mileage_source
  (vin, stat_date, protocol, source_key, source_ip, source_endpoint, phone, device_id, platform_name,
-   first_total_mileage_km, latest_total_mileage_km, daily_mileage_km, sample_count,
-   first_event_time, latest_event_time, quality_status, quality_reason)
+   first_total_mileage_km, latest_total_mileage_km, daily_mileage_km, pure_hydrogen_mileage_km,
+   sample_count, pure_hydrogen_sample_count, first_event_time, latest_event_time,
+   latest_pure_hydrogen_active, latest_pure_hydrogen_mode_known, quality_status, quality_reason)
 SELECT
  s.vin,
  s.stat_date,
@@ -471,9 +517,13 @@ SELECT
  ` + normalizePlatformFirstTotalSQL + ` AS first_total_mileage_km,
  ` + normalizePlatformLatestTotalSQL + ` AS latest_total_mileage_km,
  ` + normalizePlatformDailySQL + ` AS daily_mileage_km,
+  SUM(s.pure_hydrogen_mileage_km) AS pure_hydrogen_mileage_km,
  SUM(s.sample_count) AS sample_count,
+  SUM(s.pure_hydrogen_sample_count) AS pure_hydrogen_sample_count,
  MIN(s.first_event_time) AS first_event_time,
  MAX(s.latest_event_time) AS latest_event_time,
+  CAST(SUBSTRING_INDEX(GROUP_CONCAT(s.latest_pure_hydrogen_active ORDER BY s.latest_event_time DESC, s.updated_at DESC SEPARATOR ','), ',', 1) AS UNSIGNED) AS latest_pure_hydrogen_active,
+  CAST(SUBSTRING_INDEX(GROUP_CONCAT(s.latest_pure_hydrogen_mode_known ORDER BY s.latest_event_time DESC, s.updated_at DESC SEPARATOR ','), ',', 1) AS UNSIGNED) AS latest_pure_hydrogen_mode_known,
  CASE
 	WHEN ` + normalizePlatformOutsideDailyRangeSQL + ` THEN '` + QualityInvalidDelta + `'
    ELSE '` + QualityOK + `'
@@ -530,6 +580,16 @@ ON DUPLICATE KEY UPDATE
  phone = COALESCE(NULLIF(TRIM(VALUES(phone)), ''), phone),
  device_id = COALESCE(NULLIF(TRIM(VALUES(device_id)), ''), device_id),
  platform_name = COALESCE(NULLIF(TRIM(VALUES(platform_name)), ''), platform_name),
+  pure_hydrogen_mileage_km = VALUES(pure_hydrogen_mileage_km),
+  pure_hydrogen_sample_count = VALUES(pure_hydrogen_sample_count),
+  latest_pure_hydrogen_active = CASE
+    WHEN latest_event_time IS NULL OR VALUES(latest_event_time) >= latest_event_time THEN VALUES(latest_pure_hydrogen_active)
+    ELSE latest_pure_hydrogen_active
+  END,
+  latest_pure_hydrogen_mode_known = CASE
+    WHEN latest_event_time IS NULL OR VALUES(latest_event_time) >= latest_event_time THEN VALUES(latest_pure_hydrogen_mode_known)
+    ELSE latest_pure_hydrogen_mode_known
+  END,
  first_total_mileage_km = ` + upsertSourceMergedFirstTotalSQL + `,
  latest_total_mileage_km = ` + upsertSourceMergedLatestTotalSQL + `,
  daily_mileage_km = ` + upsertSourceMergedDailySQL + `,
@@ -673,13 +733,14 @@ const selectedSourceIdentitySampleCountSQL = `(

 const projectDailyMileageSQL = `
 INSERT INTO vehicle_daily_mileage
-  (vin, stat_date, protocol, source_id, daily_mileage_km, latest_total_mileage_km)
+  (vin, stat_date, protocol, source_id, daily_mileage_km, pure_hydrogen_mileage_km, latest_total_mileage_km)
 SELECT
  s.vin,
  s.stat_date,
  s.protocol,
  ds.id,
  s.daily_mileage_km,
+  LEAST(s.pure_hydrogen_mileage_km, s.daily_mileage_km),
  s.latest_total_mileage_km
 FROM vehicle_daily_mileage_source s
 LEFT JOIN vehicle_data_source ds
@@ -688,6 +749,7 @@ WHERE s.vin = ?
  AND s.stat_date = ?
  AND s.protocol = ?
  AND s.quality_status = '` + QualityOK + `'
+  AND s.latest_total_mileage_km IS NOT NULL
  AND s.daily_mileage_km BETWEEN 0 AND (? * GREATEST(1, DATEDIFF(DATE(s.latest_event_time), DATE(s.first_event_time))))
  AND (ds.id IS NULL OR ds.enabled = 1 OR (
    COALESCE(NULLIF(TRIM(ds.source_kind), ''), 'UNKNOWN') = 'UNKNOWN'
@@ -710,6 +772,7 @@ LIMIT 1
 ON DUPLICATE KEY UPDATE
  source_id = VALUES(source_id),
  daily_mileage_km = VALUES(daily_mileage_km),
+  pure_hydrogen_mileage_km = VALUES(pure_hydrogen_mileage_km),
  latest_total_mileage_km = VALUES(latest_total_mileage_km),
  updated_at = CURRENT_TIMESTAMP
 `
--- a/go/vehicle-gateway/internal/stats/source_mileage_test.go
+++ b/go/vehicle-gateway/internal/stats/source_mileage_test.go
@@ -176,10 +176,10 @@ func TestUpsertSourceMileageTruncatesSubsecondEventTimesAtDayBoundary(t *testing
 	if len(exec.calls) != 1 {
 		t.Fatalf("exec calls = %d, want 1", len(exec.calls))
 	}
-	if got := exec.calls[0].args[13]; got != previous.Truncate(time.Second) {
+	if got := exec.calls[0].args[15]; got != previous.Truncate(time.Second) {
 		t.Fatalf("first event arg = %v, want %v", got, previous.Truncate(time.Second))
 	}
-	if got := exec.calls[0].args[14]; got != current.Truncate(time.Second) {
+	if got := exec.calls[0].args[16]; got != current.Truncate(time.Second) {
 		t.Fatalf("latest event arg = %v, want %v", got, current.Truncate(time.Second))
 	}
 }
@@ -211,6 +211,27 @@ func TestUpsertSourceMileageUsesEventTimeBoundaries(t *testing.T) {
 	}
 }

+func TestUpsertSourceMileageAccumulatesOnlyContinuousPureHydrogenIntervals(t *testing.T) {
+	for _, want := range []string{
+		"pure_hydrogen_mileage_km = pure_hydrogen_mileage_km + CASE",
+		"VALUES(latest_event_time) > latest_event_time",
+		"latest_pure_hydrogen_mode_known = 1",
+		"latest_pure_hydrogen_active = 1",
+		"VALUES(latest_pure_hydrogen_mode_known) = 1",
+		"VALUES(latest_pure_hydrogen_active) = 1",
+		"VALUES(latest_total_mileage_km) - latest_total_mileage_km",
+	} {
+		if !strings.Contains(upsertSourceMileageSQL, want) {
+			t.Fatalf("pure hydrogen accumulation SQL missing %q:\n%s", want, upsertSourceMileageSQL)
+		}
+	}
+	pureUpdate := strings.Index(upsertSourceMileageSQL, "pure_hydrogen_mileage_km = pure_hydrogen_mileage_km + CASE")
+	latestTotalUpdate := strings.Index(upsertSourceMileageSQL, "latest_total_mileage_km = CASE")
+	if pureUpdate < 0 || latestTotalUpdate < 0 || pureUpdate > latestTotalUpdate {
+		t.Fatalf("pure hydrogen increment must use the previous odometer before MySQL updates latest_total_mileage_km:\n%s", upsertSourceMileageSQL)
+	}
+}
+
 func TestUpsertSourceMileageRechecksMergedDailyRange(t *testing.T) {
 	if maxSelectedDailyMileageKMSQL != "2500" || maxNegativeMileageJitterKMSQL != "1" {
 		t.Fatalf("SQL mileage limits drifted from Go quality constants: selected=%s jitter=%s", maxSelectedDailyMileageKMSQL, maxNegativeMileageJitterKMSQL)
@@ -515,6 +536,7 @@ func TestProjectDailyMileageSelectsCandidateAndMarksSource(t *testing.T) {
 		"WHEN 'UNKNOWN' THEN 2",
 		"ds.trust_priority",
 		"s.quality_status = '" + QualityOK + "'",
+		"s.latest_total_mileage_km IS NOT NULL",
 		"COALESCE(NULLIF(TRIM(ds.source_kind), ''), 'UNKNOWN') = 'UNKNOWN'",
 		"AND (ds.source_code IS NULL OR TRIM(ds.source_code) = '')",
 		"AND (ds.platform_name IS NULL OR TRIM(ds.platform_name) = '')",
--- a/go/vehicle-gateway/internal/stats/source_test.go
+++ b/go/vehicle-gateway/internal/stats/source_test.go
@@ -225,6 +225,26 @@ func TestDailyMileageSourceSchemaIncludesQueryIndexes(t *testing.T) {
 	}
 }

+func TestDailyMileageSchemaIncludesPureHydrogenEvidence(t *testing.T) {
+	for _, want := range []string{
+		"pure_hydrogen_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0",
+	} {
+		if !strings.Contains(DailyMileageTableSQL, want) {
+			t.Fatalf("daily mileage schema missing %q:\n%s", want, DailyMileageTableSQL)
+		}
+	}
+	for _, want := range []string{
+		"pure_hydrogen_mileage_km DECIMAL(18,3) NOT NULL DEFAULT 0",
+		"pure_hydrogen_sample_count BIGINT NOT NULL DEFAULT 0",
+		"latest_pure_hydrogen_active TINYINT(1) NOT NULL DEFAULT 0",
+		"latest_pure_hydrogen_mode_known TINYINT(1) NOT NULL DEFAULT 0",
+	} {
+		if !strings.Contains(DailyMileageSourceTableSQL, want) {
+			t.Fatalf("daily mileage source schema missing %q:\n%s", want, DailyMileageSourceTableSQL)
+		}
+	}
+}
+
 func containsStatement(statements []string, fragment string) bool {
 	for _, statement := range statements {
 		if strings.Contains(statement, fragment) {