On the emission behaviors of light-duty vehicles under the real driving cycle

This article is aimed at presenting the author's comparative study and analysis on the two different experimental systems: GPS and HEX+CAN,so as to get enough testing data on the speed and other parameters of the light-duty vehicles under the actual road-traffic conditions.For the given purpose,we have summarized and synthesized a real driving cycle of urban-use light-weight vehicles by a software from the testing speed data.And,then,it was found that,compared to the standard driving cycle,the average speed of the actual driving cycle tends to be much lower with its idle speed ratio being higher,though the acceleration ratio of the two situations proves to be almost the same,even at a lower speed changing rate.Thus,comparing the emission behaviors of the two cycles on the emission testing platform,we have found that,when the car was started in cold condition,the CO emission of the real driving cycle proves 35.1% higher than usual,with HC being 13.4% higher and NOx being 23.1% higher.However,when the car was started in hot,the CO emission of a real driving cycle would be 21.4% higher,with HC emission being 26.3% and NOx being 13.1% higher.Thus,it can be said that the real driving cycles can be a lot more different from the standard driving one not only for a cold-started car,but also the hot-started one. Therefore,standard driving cycles should never stand for the real emission level of vehicle fuel pollutants in the actual traffic conditions of different towns and cities.