Research On Heavy-Duty Diesel Vehicle Of Stage Ⅳ Emission Control Technology

With better fuel economy, power and durability, diesel engine and vehicle makes a rapid development in recent years. However, as the main mobile pollutant for the urban air pollution, diesel vehicle emissions especially nitrogen oxides (NO_x) and particulate matter (PM) has received more and more attention, and makes an inestimable contribution rate to the city air quality. To reduce vehicle exhaust emissions, The United States, Europe, Japan already have set up their own motor vehicle emission regulations, which provide the basis and reference for China's vehicle emission standards and regulations based on our country's condition.Through summarizing domestic and international auto-fuel projects, diesel parameters(mainly sulfur contents, cetane number and cetane index, aromatics, density, viscosity etc) influence on vehicle emission characteristic was deeply investigated, which provides scientific basis for constituting the fourth stage diesel standard to accord with the national conditions; Diesel has a high thermal efficiency, reducing the PM and NO_x emission level is the main problem for diesel technology in the future, to meet the escalating emissions regulations and the lower emission limits requirements, the only way is to improve the diesel engine cleaning technology constantly, such as electronic control and high pressure fuel injection technology, exhaust turbo and cooling technology, optimizing the structure of the combustion chamber and exhaust gas recirculation technology. Meanwhile, in order to meet stage IV emission standard, heavy diesel vehicles are required to install exhaust after-treatment devices (SCR technology and EGR / DPF technology) to reduce PM and NO_x emission factors.This article mainly focuses on the comparative analysis between two different exhausts after treatment control technology (SCR and EGR / DPF) in the following three aspects, such as technical continuity, feasibility, cost and so on. In the facing of SCR technology being used more and more by international heavy diesel vehicles, article makes a deep research on emission characteristics of diesel engine parameter test and vehicle road test with SCR technology, and also makes an analysis and statistics of Urea amount in SCR technology, the international heavy diesel vehicle emissions regulations and the implementation experience provides a reference for the Urea supply of China'sâ…£vehicle and infrastructure construction.