基于滑模跟踪控制的汽车发动机在线监测与故障诊断

On-line performance supervision and fault diagnosis for automotive enginesusing sliding mode tracking control

根据滑模控制理论,设计了汽车发动机动态转矩滑模跟踪控制方案,通过改变动态转矩,使曲轴转速平方的估计值不断跟踪其测量值,二者误差逐渐减小,动态系统收敛性得以保证,从而可以估计动态转矩和平均动态转矩。若发动机某缸(或某几缸)平均动态出现较大的负值,则可断定该缸存在故障。试验结果表明,该方法对建模误差和参数变化具有很强的鲁棒性,在中低转速和变化工况下均能实时监测气缸工作情况,准确诊断和定位故障,并能判断故障的严重程度。

A sliding mode tracking controller was designed to estimate the dynamic torque of automotive engines. The sliding mode control design is based on a dynamic model of the crankshaft. The sliding controller continuously tracks the varying crank speed which is controlled by changing the dynamic torque. During the tracking, the speed estimation errors decrease and the dynamic stability is assured. The mean dynamic torque during the power stroke can be used to monitor the engine performance and diagnose faults. Experimental results with a four-cylinder engine indicate that the sliding mode method has good robustness, accuracy and tracking ability, and is a suitable tool for real-time performance supervision and fault diagnosis on vehicles with various engine operating conditions.