Abstract: Based on the real driving emission test results of 27 light gasoline vehicles meeting different emission stages,the real driving emission factors of light vehicles are calculated by dividing the cold start process and hot running process,combined with the VSP Bin interval distribution in CLTC cycle. The results show that with the tightening of emission standards,the CO and NO_x emissions of light vehicles show an obvious downward trend,and the PN emission decreases rapidly in the China VI stage. During hot running,the emissions of CO,NO_x and PN are higher in Bin 25 and Bin 37 with higher VSP. The hot running weighted emission factors of CO,NO_x and PN of China VI light vehicles are 0.133g/km,0.019g/km and 2.67×10¹¹/km respectively. According to the calculation of vehicle usage scenarios in Beijing,the daily emissions of CO,NO_x and PN of China VI light vehicles can reach 12.47g,1.47g and 2.60×10¹³/km respectively. Through the WLTC test of different ambient temperatures,the influence factors of ambient temperature on pollutant emission are obtained,and the emission factors under different ambient temperatures are calculated.

Key words: CLTC, real driving emission, light-duty gasoline vehicles, ambient temperature