Overview
ISO/TR 17326:2023 specifies test methods for assessing cold start performances of fuel cell hybrid electric vehicles (FCHEV) fuelled with compressed hydrogen under sub‑zero temperature conditions. It applies to passenger cars and light‑duty trucks with a maximum authorized total mass of 3 500 kg. The document defines soak conditions, cold‑start and launch test procedures, data acquisition and processing, and reporting requirements to evaluate vehicle readiness, fuel‑cell power delivery and hydrogen consumption during cold starts.
Key topics and technical requirements
- Scope & terminology
- Applies to FCHEV (fuel cell hybrid electric vehicles) up to 3 500 kg and uses terms from ISO/TR 8713.
- Test temperature control
- Test chamber temperature controlled within ±2 °C of setpoint; preferred setpoint −7 °C, range 0 °C to −30 °C.
- Soak period: effective soak time ≥ 12 h.
- Soak and start procedures
- Vehicle and RESS (rechargeable energy storage system) preparation allowed per manufacturer; adjustments logged.
- Option to use an external hydrogen tank per ISO 23828 for hydrogen‑consumption measurement.
- Cold start performance test
- Data sampling begins at vehicle start and continues until shutdown; monitor fuel‑cell stack voltage/current and RESS voltage/current.
- Record time to vehicle “READY” and time until fuel‑cell stack output reaches ≥ 1 kW; hydrogen consumption during the interval may be recorded.
- Launch performance test
- Determine dynamometer load coefficient (road‑load reproduction per ISO 10521 series) and simulate sub‑zero road behavior.
- After soak and start, operate at full accelerator until fuel‑cell power reaches ≥ 50% of rated power, record time and hydrogen used; then perform a regional ADT drive cycle.
- Instrumentation accuracy
- Examples: Time ±0.1 s, Speed ±1 %, Temperature ±1 °C, Mass ±0.5 kg (see Table 1).
- Data processing & records
- Specifies data acquisition requirements, processing methods (Annex B) and test records (Annex C).
Applications and users
ISO/TR 17326:2023 is intended for:
- Vehicle manufacturers validating FCHEV cold‑start performance and thermal management design
- Test laboratories and certification bodies conducting reproducible cold‑start and launch tests
- R&D teams optimizing fuel‑cell control strategies and hydrogen consumption during cold conditions
- Suppliers of fuel‑cell systems, RESS and hydrogen storage assessing component behavior in low temperatures
Practical uses include design verification, homologation support, component benchmarking, and comparative testing across vehicle models.
Related standards
- ISO/TR 8713 - Electrically propelled road vehicles - Vocabulary
- ISO 14687 - Hydrogen fuel quality
- ISO 23828 - FCHEV related testing
- ISO 10521 series - Road load and chassis dynamometer methods
- ISO 6469 series - Safety and fuel‑cell system definitions
Keywords: ISO/TR 17326:2023, fuel cell road vehicles, cold start performances, sub‑zero temperature, compressed hydrogen, FCHEV, test methods, hydrogen consumption, dynamometer.