涡轮增压柴油机EGR-VGT协调控制器的设计与仿真

Design and Simulation of a Coordinated EGR-VGT Controller for a Turbocharged Diesel Engine

针对柴油机废气再循环(EGR)和可变几何截面涡轮增压器(VGT)控制回路存在的强烈耦合作用,讨论了EGR-VGT的协调控制问题。根据不同控制器对排放的影响,基于平均值模型,通过对被控对象的控制特性分析,选择与排放密切相关的氧气/燃油比和EGR率作为反馈变量,建立了EGR-VGT协调控制器。在MATLAB/Simulink环境下,通过仿真验证了所建立的控制器的瞬态控制效果。结果表明,被控变量能够很好地跟踪其目标值,未出现明显的超调,稳态误差控制在5%以内,瞬态响应时间小于1s。

Aimed at the strong coupling effects between the exhaust gas recirculation （EGR） control loop and the variable geometry turbocharger （VGT） control loop, the coordinated EGR - VGT control problem was discussed. According to influences of the different controllers on the en- gine emission, the control characteristic of the controlled plant was analyzed based on a mean value engine model. The oxygen / fuel ratio and the EGR rate closely related to the engine emission were selected as feedback variables, and an EGR - VGT coordinated controller was established. The tran- sient control effect of the controller was verified by simulation in the environment of MATLAB/Simu- link. The results show that the target values can be tracked well by the controlled variables without obvious overshoot, and steady -state error is controlled within 5%, and the transient response time is less than 1 s.