GB/T 40711.4-2021Off-cycle technology/device energy saving effects evaluation methods for passenger cars—Part 4:Regenerative braking system (English PDF)

1 Scope

This document specifies the energy saving effects evaluation methods of the regenerative braking system for passenger cars.

This document applies to M1 vehicles with a regenerative braking system, of which the maximum design gross mass does not exceed 3 500 kg.

This document applies to vehicles capable of burning gasoline or diesel, not to externally rechargeable hybrid electric vehicles.

2 Normative references

The contents of the following documents constitute the indispensable clauses of this document through normative references in the text. For dated references, only the version corresponding to that date is applicable to this document; for undated references, the latest version (including all amendments) is applicable to this document.

GB 18352.6-2016, Limits and measurement methods for emissions from light-duty vehicles (CHINA 6)

GB/T 19233-2020, Measurement methods of fuel consumption for light-duty vehicles

GB 19578, Fuel consumption limits for passenger cars

GB/T 19596, Terminology of electric vehicles

GB/T 19753-2021, Test methods for energy consumption of light-duty hybrid electric vehicles

GB 27999, Fuel consumption evaluation methods and targets for passenger cars

4 General requirements

4.5 Test the regenerative braking system in accordance with the requirements of Chapter 5; record the test vehicle parameters and test data in accordance with the provisions of Appendix A. Calculate the energy saving effects according to the requirements of Chapter 6; express the calculation result in liters per 100 kilometers (L/100 km); round (round up) to two decimal places.

5 Test procedures

6 Test results

Appendix B (Normative) Regenerated energy test method

B.1 Before the test, it shall be preheated by running at least one WLTC or CLTC-P on the chassis dynamometer. The selection of the test cycle during the preheating process shall be consistent with the test specified in B.2.

B.2 Test the vehicle under WLTC and CLTC-P respectively according to the requirements of 6.1, 6.2 and 6.4 in GB/T 19233-2020. During the test, measure and record, in real time, the current I (A) and the voltage U (V) of busbars of all motor terminals involved in the braking energy recovery; carry out the test three times in total. The 3 tests shall be carried out continuously, so as to keep the vehicle in a fully preheated state; otherwise, it shall be preheated again in accordance with B.1.

B.3 After one test and before the next one, the SOC shall be confirmed or adjusted according to the requirements of 5.1.2.

B.4 The regenerated energy shall be calculated according to Formula (B.1):

Where:

EN - the regenerated energy of the vehicle when it is tested according to WLTC or CLTC-P, in watt-hours (W·h); k - the serial number of the motor that is involved in the braking energy recovery; n - the number of motors that are involved in the braking energy recovery; t0 - the moment when the test starts, in seconds (s); tend - the moment when the test ends, in seconds (s);

Ik - the feedback current of the motor terminal busbar whose serial number is k, which is involved in the braking energy recovery during the deceleration process, in amperes (A);

Uk - the voltage of the motor terminal whose number is k, which is involved in the braking energy recovery, in volts (V); […]