Study on probability of compliance with China 6 standard for the emission from light duty gasoline vehicles

The emission characteristics of the gasoline direct injection (GDI) vehicle and the common port fuel injection (PFI) gasoline vehicle at China 5 emission level were studied under the test procedure of room temperature (23 ℃) and low temperature (-7 ℃) cold-start according to China 6 standard. The results show that the CO and HC of PFI vehicles are about 4.3%-39.5% higher than those of GDI vehicles, and the emission of NO_x, particulate matter (PM) and particulate number (PN) is about 69.8%-82.7% lower. Because of the high emission of PN, GDI vehicles are more difficult to reach China 6 standard than PFI ones. In term of speeds, the emission of various gaseous pollutants at low speed is much higher than that at medium speed, high speed and super high speed. However, NO_x emissions at super high speeds have increased, only about 22.2% lower than that of low speed.