Analysis on the progress of evaporative emission (type IV) standards for light-duty vehicles in China

Abstract

This paper briefly introduces the progress of evaporative emission standards for light-duty vehicles in developed countries such as the United States and Europe, and the test procedures specified in the latest evaporative emission standard were concluded. Moreover, the development of evaporative emission standards for light-duty vehicles in China was comparatively analyzed. The evaporative emission test data from 2004 to 2019 was randomly selected for analysis of the trend of evaporative emission performance of vehicles in China with the use of EPR. Affected by the more stringent China 6 Evaporative Emissions standards issued in 2016, the EPR value of the evaporative emission test conducted according to the China 5 had continuously decreased to 41% in 2018. Subsequently, the EPR value increased again to a value of 60% in 2018 and 2019 due to strengthen of the emission limit from 2g to 0.7g and the raise of deterioration factor. Finally, based on the world's latest evaporative emission standards, the development trend of evaporative emission standards for light-duty vehicles in China is forecasted. The application of canister bench aging test, BETP, running loss emission test, and a test cycle with Chinese characteristics may be more conducive to control the light-duty vehicle emissions. Compared with the LEV 3, the evaporative emission limit of 0.7g/test specified in China 6 is still relatively larger. In addition, strengthen the control of durability test and in-use emission performance test would makes the HC emission less during the actual operation of the vehicle.

A Comparison of the Evaporative Emissions Performance of Light-Duty Vehicles under US Tier 3 and China 6 Test Conditions

“…The authors found that China 6 vehicles had a 98.8% reduction in refueling emissions relative to China 5 vehicles. Zhong et al provided a summary of China 3, China 4, China 5, and China 6 certification data for hot soak and diurnal evaporative emissions from a random selection of 20 vehicles from each year spanning 2004 to 2019 [23]. While the results show that significant progress has been made to reduce refueling and evaporative emissions with the introduction of China 6, Zhong et al concluded that there remain further opportunities to reduce evaporative emissions in China.…”