GB/T 44131-2024Post-crash safety requirements for fuel cell electric vehicles (English PDF)

5.2 Post-crash safety requirements for CHSS

5.2.1 Fuel leakage limit of CHSS According to the test method specified in 7.1, within the leakage test time Deltat, the sum of the average hydrogen leakage rates of all hydrogen storage cylinders shall not exceed 118 L/min (standard state). NOTE. Deltat is a calculated value, which is calculated either according to formula (2) or formula (10), depending on the medium filled in the hydrogen storage cylinder during the test.

5.2.2 Concentration limit in closed or semi-closed spaces REESS shall meet the requirements of

4.4 of GB/T 31498-2021.

5.4.3 Special safety requirements for hydrogen system Within the leakage test time, Deltat, after the collision, the CHSS and fuel cell engine shall not catch fire or explode.

6.1 Vehicle preparation before test

6.1.1 For externally rechargeable fuel cell electric vehicles, the REESS shall be fully charged according to the method specified in GB/T 18385 and tested within 24 hours.

6.1.2 For non-externally rechargeable fuel cell electric vehicles, the REESS shall be prepared for test in normal operating conditions.

6.1.3 The manufacturer shall install pressure and temperature measuring equipment that meets the requirements of Table 1 on the CHSS and provide a metrological certificate. Before the test, the testing agency may refer to Annex A for verification and prepare for the post-crash fuel leakage test in accordance with 7.1.1.

6.1.4 The gas concentration test in closed or semi-closed spaces shall be prepared in accordance with 7.2.

6.1.5 For frontal collision, lateral collision and rear-end collision tests, preparations shall be made in accordance with the test methods specified in GB 11551, GB 20071 and GB 20072, respectively.

6.1.6 The sled test shall be prepared in accordance with

7.3.1 and 7.3.2.

6.2 Collision test

6.2.1 The form and test method for the frontal collision test of the vehicle shall be carried out in accordance with the relevant provisions of GB 11551.

6.2.2 The form and test method for the lateral collision test of the vehicle shall be carried out in accordance with the relevant provisions of GB 20071.

6.2.3 The form and method for the rear-end collision test of the vehicle shall be carried out in accordance with the relevant provisions of GB 20072.

6.2.4 The sled test shall be carried out in accordance with the relevant provisions of 7.3.

6.2.5 The lateral collision and rear-end collision tests of the vehicle shall be carried out in accordance with the relevant provisions of 7.4. where. VHe - the value of the average volume flow rate of helium in the time interval, in liters per minute (L/min). Use formula (18) to convert the average helium flow rate into the average hydrogen flow rate.

7.1.4 Fuel leakage test when the pressure sensor is located outside the hydrogen storage cylinder

7.1.4.1 After the collision test, the following requirements shall be followed.

a) If the main shut-off valve of the hydrogen storage cylinder is not closed after the collision, the fuel leakage rate during the hydrogen filling test shall be calculated according to

7.1.2 or according to 7.1.3;

b) If the main shut-off valve of the hydrogen storage cylinder is closed within 5 s after the collision, the hydrogen storage cylinder has no leakage, and the fuel leakage rate of the hydrogen storage cylinder can be regarded as 0 L/min (standard state);

c) If the main shut-off valve of the hydrogen storage cylinder is closed within 5 s after the collision, and the hydrogen storage cylinder has leakage, the main shut- off valve of the hydrogen storage cylinder shall be opened (if the pressure sensor value drops significantly, the external pipeline shall be blocked before opening the main shut-off valve of the hydrogen storage cylinder), and calculate the fuel leakage rate during the hydrogen filling test according to

7.1.2 or the helium filling test according to 7.1.3.

7.1.4.2 The sum of the leakage rates of each hydrogen storage cylinder is the fuel leakage rate of CHSS.

7.2 Gas concentration test in enclosed or semi-enclosed spaces after collision

7.2.1 Before collision, the windows, doors or hatches of the passenger compartment, luggage compartment, cargo compartment and other enclosed or semi-enclosed spaces where gas accumulation may occur shall be closed. The gas concentration sensor shall be located in enclosed or semi-enclosed spaces, the specific location is as follows:

a) Within 250 mm below the center of the roof above the driver's seat or the top of the passenger compartment (as close to the roof as possible);

b) Within 250 mm above the floor in front of the rear seat (or close to the rear seat) of the passenger compartment (as close to the floor as possible);

c) Within 100 mm below the top of the luggage compartment and cargo compartment of the vehicle that are not directly affected by the collision impact (as close to the top as possible);

d) For buses and trucks with multiple luggage compartments and cargo compartments, a gas concentration sensor shall be installed in each compartment;

e) The specific layout of sensors in other enclosed or semi-enclosed spaces where gas accumulation may occur shall be determined jointly by the testing agency and the manufacturer.

7.2.2 The gas concentration sensor shall be firmly installed and protected to prevent it from being damaged by debris, airbag exhaust gas and projectiles during the collision test.

7.2.3 The full-scale measurement value of the gas concentration sensor shall be at least 25 % greater than the concentration limit, the total measurement error of the gas concentration sensor shall be less than ±5 % at the concentration limit, and the T90 response time of the sensor shall be less than 15 s. NOTE. T90 is the time consumed when the sensor indication changes from 0 to 90 % of the true value of the measured gas concentration in the environment.

7.2.4 Data collection starts after the collision, the sampling frequency shall be not less than

5 Hz, and the measurement time shall be Deltat.

7.3 Sled test

7.3.1 Before the test, fill the hydrogen storage cylinder with nitrogen equivalent to the mass of hydrogen at the rated pressure, or the mass of the hydrogen storage cylinder plus the test load equivalent to the mass of hydrogen at the rated pressure can be used instead.

7.3.2 During the test, according to the size structure of the whole vehicle body or part of the vehicle body installed with CHSS (hereinafter referred to as the "test piece") and the actual installation method of the original vehicle, fix the test piece on the test platform. The installation method shall not strengthen the fixation of CHSS.

7.3.3 The test is completed as follows:

a) The acceleration of the sled is measured according to the CFC 60 frequency level characteristics in ISO 6487.2015;

7.4.2.2 The CHSS shall be tested at the installation position on the vehicle, including accessories, brackets and protective structures (if applicable). The CHSS shall be installed on a complete vehicle or frame, and the vehicle or frame shall be fixed in the manner specified in

5.4 of GB 26512-2021.

7.4.2.3 The impactor shall comply with the requirements of

5.5.4 of GB 26512- 2021.

7.4.2.4 The collision energy shall be

29.4 kJ. If the test is carried out at a higher collision energy and the CHSS meets the requirements of

5.2.1 and 5.2.3, the test can be considered to meet the requirements.

7.4.2.5 The following requirements shall be followed for lateral collision and rear-end collision tests. - For lateral collision, the collision direction shall be perpendicular to the longitudinal center plane of the vehicle, the impactor shall hit the most unfavorable position on the front side of the CHSS position on the test vehicle, and the center of gravity of the impactor shall correspond to the geometric center of the gas cylinder; - For rear-end collision, the collision direction shall be horizontal and parallel to the longitudinal center plane of the vehicle, the impactor shall hit the most unfavorable position on the rear of the CHSS position on the test vehicle, and the center of gravity of the impactor shall correspond to the geometric center of the gas cylinder.