Study Of Detection Of Vehicle Exhaust And Impact Factors In Chongqing City

Objective: Utilize the test data by checking vehicle exhaust inChongqing, and find out the related factors by analyzing, in order toeffectively control the pollution of vehicle exhaust and put forward thetechnical measures to reduce harmful substance and the air pollution, thenprotect the environment and human health.Method: Use exhaust gas analyzer to test vehicle exhaust with themethod of steady state condition method, focusing on carbon monoxide(CO), Hydrocarbon Compounds (HC) and nitrogen monoxide (NO).Group the cars by the useful lives: less than2year Group,2to4year group,4to6year group,6to8year group,8to10year group and10year or moregroup. Group the cars by the driving distance: less than50thousandkilometer group,50to100thousand kilometer group,100to150thousandkilometer group,150to200thousand kilometer group,200to250thousandkilometer group,250to300thousand kilometer group, and300thousandkilometer or more group. Group the cars by the temperature: less than10℃group，10to20℃group,20to30℃group and30℃or more group.Group the cars by their discharge capacity:1L group,1.6L group,1.8L group,2L group. And provide the yellow or green markers according theresult of the test. The final results will be processed and analyzed.Results:1.15000cars have been detected totally, and there are2117carsunqualified. Qualified rate is85.89%.2.According to the results, there are differences in unqualified rate ofemission detection in various groups (grouped by useful lives, drivingdistance, temperature, discharge capacity), and the difference isstatistically significant.(P<0.05)1)In terms of the useful lives, there is obviously different (P<0.001) inthe unqualified between each group detected. The unqualified rate wouldbe higher if the cars have been used longer.2)In terms of driving distance, the difference in unqualified rate isobvious between less than50thousand kilometer group and othergroups.(P<0.001)3)In terms of temperature, the difference(P<0.005) in unqualified rateis obvious between each group except the groups of10℃to20℃and20℃to30℃, which is no statistically significant(P=0.998).4)In terms of discharge capacity, the difference (P<0.001) inunqualified rate is obvious between each group except the group of1.6Land1.8L, which is no statistically significant (P=0.456). 3. According to the vehicle exhaust value:1)The value of detection index (HC,CO,NO) shows significantdifference in the group that grouped by the useful lives.(F is121.79,249.58,364.78respectively, P<0.01). if compared with any two, all the emissionvalue showed great difference except that there is no obvious difference inthe emission value between the8~year group and10~year group.2)In terms of driving distance, the value of detection index showsdifference generally.(F is41.95,78.90,145.76respectively, P <0.01). Withthe increase of driving distance, there is uneven distribution in the emissionof the vehicle. If compisd with any two, there is great difference between0~thousand kilometer group and other groups, There are nosignificant differences between the other groups.3) The value of detection index exists a lot of difference underdifferent temperatures (F is91.3,38.39,154.66respectively, P<0.01). Itresults between0~℃group and other groups statistically significantdifference.4)In terms of discharge capacity, the value of detection index showssignificant difference (F is134.81,131.13,456.05respectively, P<0.01).The three detection indexes from1L group are greatly different from othergroups.Conclusion:Qualified rate of vehicle exhaust test is relatively high, reaching the specified level basically. Unqualified rate would be higher if the vehicleshave been used longer with more gas emitted. The emission value andqualified rate will vary with driving distance, temperature and dischargecapacity varied. In addition, there are many factors that will affect the gasemission, such as manual manipulation, vehicle performance and the wayto maintain. They will all affect the emission value.