Simulation and Experimental Research on the Combustion and Emission Characteristics of Diesel Engines Uusing EGR
Under the condition of exhaust gas recirculation(EGR),a diesel engine and EGR system model were con-structed using a diesel engine as the experimental object.Study the impact of EGR system on the performance,combus-tion,and emission characteristics of diesel engines.The experimental results show that with the increase of EGR open-ing,the introduction of exhaust gas reduces the concentration of oxygen(O2),prolongs the ignition period,slows down the combustion speed,and leads to a significant decrease in the maximum burst pressure;EGR reduces the air-fuel ratio,prolonging the ignition delay period of the combustion process towards the expansion stage.Some fuels cannot fully burn near the top dead center,resulting in a slight decrease in power and a slight increase in fuel consumption.However,the use of EGR reduces the formation of nitrogen oxides(NOx)during combustion in the cylinder.At medium to high loads,as the opening of the EGR valve increases,the reduction in NOx is extremely significant,with a maximum reduction of 52.4％.The conclusion indicates that the reasonable application of EGR system can significantly suppress nitrogen oxide(NOx)emissions while maintaining engine fuel economy and power performance.
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