Study on EGR Control Strategy for Vehicle Engine Based on Simulation

Abstract—to carry out electronic control EGR strategy in diesel engine the calculation model using GT-POWER is built. the thesis uses simulation software GT-POWER to establish the calculation model of 4JB1 intake system of turbocharged diesel engine with EGR system and the results agree well. According to the simulation results, it can predict the main performance indicators of the diesel engine when it works at the maximum torque condition, which includes A/F, IMEP, Maximum Pressure, and Intake Pressure and so on. Then after controlling the volume of gas by modifying the EGR valve, it can find out the regulation how EGR effects the engine's emissions, torque, power and the inlet temperature of turbo. Referring to the simulation results, it includes from four aspects ： EGR can significantly improve the quality of emission gas; NOx and PM have a trade-off relationship; applying higher EGR rate in heavy load can lead to the low torque and power less; the inlet temperature of turbo increases with the augment of EGR rate. In the experiment, the inlet oxygen concentration method is used to determine the EGR rate, and to realize it, the oxygen concentration detection module is also successful designed. Then a close-loop control strategy is proposed based on the EGR rate. It proves it is feasible to guide the ECU programmer development by the simulation results of engine control strategy. It is also can be referred by other engine control systems development