Optimization Of Detection Process Based On Vehicle Exhaust Emission Characteristics

With the continuous development of the economy,the income of citizens has been increasing.Motor vehicles have become an integral part of the daily travel of residents.However,with the increasing number of motor vehicles,the pollutants in vehicle exhaust have caused great damage to the air environment.There are many poisonous and harmful compounds in automobile exhaust,which are complex in composition.It will not only cause adverse effects on human body,but also damage our living environment.The environmental problems are smog,acid rain,urban heat island effect and so on.With the transformation of urban energy structure and the increase of vehicle ownership,vehicle exhaust pollution has gradually become the main source of air pollution in some cities.The contribution rate of CO,HC and NOx in motor vehicle pollutants to air pollution in some cities exceeds 50%,and is still increasing.In 2017,the total emission of CO,HC,NOx and PM from motor vehicles was about 43.597 million tons,of which co accounted for the largest proportion,accounting for about 76% of the total emissions.There are three kinds of vehicle detection methods,which are steady-state condition method and double idle speed method for gasoline vehicle detection,and free acceleration method for diesel vehicle detection.For example,in the steady-state working condition method,it is necessary to strengthen the control of the factors that may affect the final test results in the detection process,and reduce the deviation of the final test results caused by external environmental factors,non-standard human operation,and incomplete use and cleaning of testing equipment.The double idle method needs to check the air tightness of the equipment with connection before the vehicle detection,so as to reduce the impact of air tightness on the test results.The free acceleration method needs to be fully preheated to the vehicle and the detection equipment before detection,and the vehicle needs to be fully blown in the detection process to reduce the impact of carbon deposition.With the vehicle testing station to test and analyze the data of diesel vehicles and gasoline vehicles,combined with the status quo of vehicle emissions,the exhaust emissions of diesel vehicles and gasoline vehicles are studied respectively.Firstly,the exhaust smoke and particulate matter of different types of diesel vehicles under the same road conditions are analyzed.The results show that the vehicle model with less environmental pollution is obtained under the agreed road conditions.Then some diesel vehicles are selected to test PEMs on the fixed path,and the influence of different road conditions and time on exhaust emissions is obtained.The conclusion is as follows:1.PM analysis of carbon particles in exhaust gas on the same road condition shows that the relationship of exhaust smoke value is: light truck ? light enclosed truck ? light ordinary truck ? light van ? truck.2.Different vehicles in the same road conditions,vehicle type,fuel consumption have an impact on the concentration of exhaust pollutants.The changes of air temperature,wind direction and wind speed in different periods also affect the pollutant concentration.In terms of gasoline vehicles,different types of gasoline vehicles are selected,and the emission characteristics of gasoline vehicles are obtained by analyzing the concentration of pollutants under different working conditions.Combined with the status quo of gasoline vehicle emission and the existing problems in the inspection process,an early warning system and an automatic detection and analysis system for the emission of gasoline vehicles are developed.The system can realize real-time synchronous data acquisition,transmission,monitoring,analysis and decision-making,management services and other functions,realize emission monitoring and warning and purification treatment,and truly effectively meet the automatic detection and analysis management of automobile exhaust emissions..