Emission Characteristics Of Urban Vehicles And Study On Evaluation Method Of Particulate

In this paper,the vehicle tracking method is adopted and the urban car is tracked randomly within the 6th ring road of Beijing.The development is in line with China's urban vehicles real-world driving conditions.Compared with the typical driving conditions of heavy vehicles in Europe and the United States and other countries and regions,the ratio of idling speed and uniform speed of Beijing urban vehicles is lower and the proportion of acceleration and deceleration is higher,which leads to serious emission.The real world driving emissions of 6 cities in Beijing were studied by using the PEMS.The test vehicles included the van of different years and Iveco passenger transport.Based on the velocity method and the method of VSP,the emission characteristics of pollutants in different vehicles based on CO₂ emission were studied and analyzed,experimental results show that:The emission rate of CO₂ and Iveco was lower under low speed and low load,and the emission rate of CO₂ increased with the increase of velocity and acceleration.At low speed,the CO₂ emission rate of van and Iveco vehicles is basically the same,and the CO₂emission rate of high-speed segment van is obviously higher than that of IVECO.THC emissions and CO emissions are basically the same,with the VSP increases,THC and CO emission rate increases,THC and CO emissions based on CO₂ are decreasing with the increase of vehicle speed and acceleration;NOX emissions change in a small range of fluctuations,the main causes of pollutants produced by the temperature,by the vehicle speed and acceleration of the smaller;Both the PM emission rate and the CO₂-based PM emissions increase as the VSP increases.The measurement of NO_X pollutants was carried out on two urban sprinkler trucks of the same model but different reprocessing devices,one of which is equipped with a solid SCR system and the other with a urea SCR system.Experiment result show that under the influence of the city traffic,the conversion efficiency of solid SCR to NO_X at low speed and low load is superior to the urea SCR system.In order to provide the experimental basis for the accuracy of the particulate test in the portable emission testing system,two kinds of particulate matter with different measurement principles were selected.The particle size of the particulate matter?PN?was measured by the method of the particle evaluation method.The number of test equipment?plant A and plant B?is compared to the number of particulate test equipment on the bench.Which is used in equipment A principle of CPC,equipment B is the use of DC principle,results show that:.MEXA and equipment A in the steady state and transient tests have both shown a good trend of consistency;The data measured by equipment B is more difficult to reconcile with MEXA and equipment A,only the particle size is in the range of 50nm,the measured data of equipment B and equipment A are in good agreement.