Investigation Of Emission Factors Of Light-Duty Vehicles Under Different Test Cycles And Development Of Gearshift Program

Nowadays, air pollution prevention is a hot topic. As one of the source of air pollution, vehicle emissions gets more and more attention. Automobile emissions like HC, CO, NOX and particulates may be harmful to human and environment. In order to reduce the adverse effects on our lives, emissions regulations on light-duty vehicles are being upgraded and more strict emission limits will be dev eloped. This paper mainly focuses on some researches about laboratory emission test on light-duty vehicles.The paper starts with emission test cycles like NEDC, WLTC, FTP75, US06 and SC03, which are contained by some emission regulations around the world. The characteristic parameters of test cycles were statistically analyzed and compared by each other.The emission factors of 3 light-duty vehicles have been gained after over 79 tested under different test cycles in the laboratory. The influence on emission factors under cold/hot start, different oil supply technology, fuel quality, air conditioning turned on/off, different calibration conditions were analyzed from the data collected. The results show that HC and NOX are deeply affected by cold/hot start. The emission of CO is high when both the speed and acceleration are high. PN acts different between GDI vehicle and PFI vehicle.Two types of gearshift prescription for vehicles equipped with manual transmissions are calculated via VB programming. Speed si ngle-parameter gearshift prescription can be used when we can’t get the parameter of test vehicles. But the calculation of multi-parameter gearshift prescription is more accurate, and it can avoid the circumstances that the power output is insufficient. Mu lti-parameter gearshift prescription has a broader scope. Both of the two types of gearshift prescription have been revised to avoid bad operability caused by frequent gearshift.