Research Of Vehicle Emission Test On Real-World

The pollution from automobile is more and more serious, and it is harm to the human's health and the balance of the nature. For control pollution, every country raises the control requirement about the emission pollutant, constitute the compelling emission standards to control the emission from automobile.The test method and exhaust gas sampling method constitutes the emission measure method. The Drive Cycle is the primary test method. Currently, there are two kinds of exhaust gas sampling method. One is the Direct Sampling, it is a simple method, but the most serious problem of the Direct Sampling is the adsorption of sample line can result in measurement error. The other method is Constant Volume Sampling (CVS). Though the equipments and technique of CVS are more complicated than the Direct Sampling, the measure result is more accurate than that of the Direct Sampling.The main purposes of institute vehicle emission control legislations are control emission of vehicle, reduce pollutant emission on real road. However the vehicles emission tests are mainly carried out on the engine benches or chassis-dynamometers. But the test condition in the laboratory differs from the real road condition, so the test results can't accurately describe the real emission on road. Therefore it is necessary to research on vehicle emission in real road condition, and this research also is the complement of the laboratory results.We used Portable Emission Measure Systems (PEMS) as a main equipment for on-road emission tests. The EPA institutes test programs CFR1065 base on the application of PEMS. Because the environment factors can affect PEMS and result in wrong results, CFR1065 prescribes the preparation of measurement, measure plan, environment condition of measurement, etc for the PEMS.First carry out contrastive test between the CVS and the PEMS, testify the PEMS has good accuracy and reliability. We found the difference between the two results is in normal range, and we conclude the results of the PEMS can be accepted. Base onthe conclusion, we used a light-duty vehicle as test vehicle and do a series on-road emission test. The tests lines and The test time almost include all roads character of our cities.Because vehicles run as instantaneous cycle when they are driving on real road, we introduced instantaneous cycle parameters and constructed pollutant concentration emission matrix. After researched on emission instantaneous distribute. By the new analysis method, we can easily find the effect on the vehicle emission by the traffic. Because we had good choices of test conditions and test vehicle, we conclude that the emission concentration distributions can describe emission of in-use light-duty vehicle in our cities traffic.