EGR Control And Experimental Research Of Small Engine

With the continuous development of the automobile industry,more and more stringent emission regulations have been gradually introduced in various countries.At the same time,the automotive engine,especially the domestic gasoline engine for passenger vehicles,is developing towards miniaturization,direct injection and lean burn mode.As an effective measure to reduce NOx emissions,EGR Technology of exhaust gas recycling has been widely used in the field of traditional vehicle engines,but in small gasoline engines There is still much room for improvement in the application research.EGR Technology can control the proportion of oxygen in the fresh air and reduce the maximum working temperature in the cylinder by introducing the exhaust gas composition into the intake air,so as to inhibit the formation of high temperature and oxygen rich NOx generation conditions and achieve the purpose of improving engine emissions.Based on the Honda WH125-6 single cylinder engine as the research carrier,this paper uses GT-POWER to build the one-dimensional performance simulation model of the original engine,and compares the simulation results with the original bench test results.By adding the external exhaust gas recirculation model to the engine performance simulation model,and carrying out simulation analysis on the modified model,obtaining the initial EGR control map,providing the original control data for the subsequent construction of the exhaust gas recirculation control strategy.Based on MATLAB / Simulink,the control strategy of small engine exhaust gas recirculation is built,and the control strategy of exhaust gas recirculation is integrated with the original engine control strategy,and the optimization simulation model is debugged.The joint simulation control model is built in Simulink and GT-POWER environment respectively,the transmission path and transmission mode of signals are planned,the control model is further optimized in the joint simulation process,and the rationality of the joint simulation results is evaluated.Use the engine signal simulator and the host computer Meca calibration measurement software to build an engine hardware-in-the-loop test platform.Use the rapid code generation tool to flash the Simulink engine control model to the rapid prototypingcontroller with a key to generate C code.The loop test platform performs ECU hardware-in-the-loop simulation experiments on the controller functions.The experimental results show that exhaust gas recirculation can reduce the NOx content in the exhaust gas in different engine operating states,but setting an excessive EGR rate will cause the engine to lose more than 20% of the power under high-load operating conditions,and generate power under full-load operating conditions.Insufficient phenomenon,so the exhaust gas recirculation technology of small engines is mainly used in medium load conditions.This article provides research reference for the development and improvement of advanced engine technologies such as direct injection,supercharging,lean burn and other advanced engine technologies in the cylinder.