Optimization on performance of a turbocharged MPI gasoline engine by working process simulation based on target control method

摘要

At present, in the simulation of working process in engine, the trial-and-error method are often used to set the ignition advance angle, air fuel ratio and so on. It would take much time and need rich experience by using the trial-and-error method. In this paper, an optimized simulation method based on performance target control is proposed. By the method, the performance goal of torque was set as the optimization objective, and the ignition advance angle, air fuel ratio and some other parameters were set as control variables in control sub-modules of the simulation model. Then in the simulation, those control variables were adopted in a certain range automatically by PID to optimize the engine performance such as power, BSFC, in guarantees the knock and exhaust temperature under the limiting value. The method has great application to forecast and optimize the performance of new gasoline engine in the concept design. By the method, performance of one turbocharged MPI gasoline engine is optimized. At first, on the basis of experiment result, the working process numerical model of the same series naturally aspirated gasoline engine model was calibrated. Secondly, with the calibrated model, working process numerical model of the turbocharged MPI gasoline engine is established based on target control method. In succeed, turbochargers were matched, compression ratio, intake and exhaust manifold structure, cam lift and valve timing were optimized, thus made the whole performance of the engine better.