环境温度对汽油缸内直喷汽车排放的影响

Two typical Gasoline Direct Injection Vehicles (GDIVs) were selected, and emission tests in the environmental cabin were performed under Worldwide harmonized Light-duty rehicles Test Cycle (WLTC) at different ambient temperatures after the vehicles cold-started and hot-started. The gaseous pollutants and particulates in GDIV emissions were measured and analyzed with the aim of providing a theoretical basis for the GDIV emission system design and control, as well as for related research to evaluate the impact of automobile emissions on the environment. The results show that ambient temperature has a significant effect on the Particle Number (PN) and Particle Matter (PM) emission factor of the tested vehicles. The PN emission factor under the cold start condition is difficult to meet the China 6 emission limit when ambient temperature is below 14℃. The emission factors of Total Hydrocarbons (THC) and CO are significantly affected by temperature under cold start condition but are not significantly affected under hot start condition. Regardless of the hot start or cold start conditions, when the temperature gradually rises from -7℃ to 40℃, the CO₂ emission factor of the test vehicle first decreases and then increases, and the CO₂ emission factor of the two vehicles during hot start is reduced by 4% and 7% on average compared to cold start. There is no obvious rule of Nitrogen Oxide (NO_x) emission factor influenced by temperature under cold start and hot start conditions.