采用真空执行器的柴油机空气系统闭环控制

真空执行器大量应用于EGR与VNT系统,为改善空气系统控制效果,开发了一种VNT与EGR的综合控制算法。该文在分析空气系统排放特性后,提出了空气系统的控制目标。对空气系统特性的实验表明,受空行程与摩擦阻力的影响,该类执行器具有明显的滞回特性与延迟特性,因此,空气系统采用了反馈与前馈控制。实验结果表明,空气系统响应时间显著缩短,并具有良好的稳态控制效果。该控制算法能很好地实现对控制目标的精确控制,为该类系统的商业化应用奠定了基础。

Closed-loop control for diesel engine air systems equipped with vacuum actuators

Exhaust gas recirculation(EGR) and variable nozzle turbocharger technology(VNT) systems are nomally controlled by vacuum actuators.A combined control algorithm was developed for VNT and EGR systems to improve control of the air system.This paper describes the analysis of the system characteristics and the control target.Test results show the unloaded displacement and friction in the vacuum actuator lead to hysteresis and delays.Hence,the control system needs to use feedback and feedforward algorithms.Further test results verifies that the system response time is improved significantly by the algorithm with good steady-state performance.The algorithm can provide precise control to the target,and establishes the base of industrial application for the system.