Research On Exhaust Smoke Detection Methods And Emission Limit Based On Lug-down Of Diesel Vehicle

With the rising number of vehicles,city air pollution is increasing.Vehicles' emission accounted is a large proportion,and the contribution to PM2.5 in the air exceeds 20% form diesel vehicles.The relevant departments of the state has formulated a series of environmental protection laws and regulations,and has issued new emissions standards for vehicles,which has effectively controlled high-emission vehicles on the road.By the end of 2017,our country has been fully completed out of the old car,and began implementing the comprehensive country V standard in vehicle emissions since 2018.For diesel vehicles,heavy-duty diesel vehicles is accounted for nearly 90%.Lug-down is an effective method for detecting exhaust smoke value of diesel vehicles,it can simulate the actual operating condition of vehicles,and detect in full automatic detection,to avoid human intervention,and is widely used in many national cities.According to the national emission standards GB17691-2005,GB3847-2008,HJ/T241-2005 recommended industry standards,this paper has collected diesel vehicle emission inspection data from the Environmental Protection Bureau of Shaanxi Province and vehicle test station in Shaanxi province and Xi'an city vehicle exhaust pollution inspection supervision and inspection center.On the basis of these data,it compares different diesel detection methods and their advantages and disadvantages.The detection principle and testing rules of Lug-down method are introduced in detail.Because of the huge amount of data,it is proposed to use SQL(Structured Query Language)to complete the preliminary screening,deletion,integration and statistical tasks of data,so as to lay a foundation for the follow-up data analysis.Based on data processing and analysis,diesel vehicles were segmented according to vehicle type and date.Based on previous work,the principles and methods for determining emission limits of diesel vehicles in 3 and 4 countries were put forward,respectively.The limit value is according to a certain qualification rate in the industry standard,a dichotomy combined with SQL is proposed to solve the problem of accurately solving the limit value with the qualified rate.According to the principles and methods,this paper calculates the emission limits of Lug-down,and makes reasonable trade-off from the perspective of pollution control technology and social economic development,and finally get the revised limits.