Experimental Study Of Diesel NO_x Emission Control With EGR And Aftertreatment

With the development of global automobile industry, the pollution caused by automobile exhaust has become more and more severe, especially NO_x pollution. During these years, the government recognize the problem and legislate to limit the exhaust emission. As the main power source of vehicle, the question how to purify NO_x emission for diesel has become one of the hotspots. Now, technology of EGR and aftertreatment are known as the two effective methods to purify NO_x emission which are available for diesel.The objective of the thesis is to do some research on the application of EGR and aftertreatment. The following are the main contents:The first part is about experimental study on the effects of cool EGR for TR combustion system. Test results show that, the maximum of EGR rate is 15.4%;Compared with original data, the maximum of in-cylinder pressure and average temperature all drop a little. In nominal engine speed, start of combustion (SOC) doesn't change in all kinds of load but the duration period of combustion looks longer in many working conditions. It means, if the mass of recirculation exhaust is low, the main function of EGR which has influence on combustion process is heat effect. About emission control, matched with TR combustion system, cool EGR could purify NO_x emissions, but on the other hand, PM and fuel mass rate will increase a little.The second part is about experimental study on the effects of lean NO_x catalyst for diesel emission control. In the thesis, combined with DPF, Pt/Rh/Pd and Cu-ZSM-5 catalysts are prepared. The reducer are HC mixtures which are given out from the engine. The objective of the test is to gain understanding the performance about catalyst avidity, stability, lowest catalystic temperature and the range of effective catalystic temperature, etc. Test results show that, compared with Cu-ZSM-5, noble mental catalysts have better avidity, stability and the range of effective catalystic temperature looks wider. However, it is not easy to apply the Pt/Rh/Pd catalystic converter for the diesel emission and remains many problems to solve.