基于参数自适应滑模观测器的发动机气缸压力估计

气缸压力是发动机燃烧分析与故障诊断的重要参数,为了提高发动机动力学模型中的气缸压力估计精度,提出参数自适应滑模观测器设计方法.建立了基于参数自适应滑模观测器的发动机动力学模型,通过对发动机摩擦偏移及散热损耗比例系数进行修正,并依据Lyapunov稳定性理论得出观测器收敛的充分条件,在保证全局系统误差尽可能小的基础上,使得气缸压力估计误差趋近于零.仿真结果表明,参数自适应滑模观测器方法较传统滑模观测器方法具有更高的估计精度,而且该方法只需利用曲轴位置传感器得到转速信号,其硬件成本低.

Engine cylinder pressuresz estimation using the parameters adaptive sliding mode observer

Cylinder pressure is an important parameter for engine combustion analysis and fault diagnosis. In order to improve the estimation precision of cylinder pressure in the engine dynamic model, the design method of the parameter adaptive sliding mode observer is proposed. The engine dynamic model which is based on the parameter adaptive sliding mode observer is built in the paper. By revising the engine friction offset and the scaling factor of the gross heat release, and according to the Lyapunov stability theory, we get a sufficient condition which guarantee the observer convergence, finally, based on the ensurement of the overall error system as small as possible, the cylinder pressure estimation error reduce is close to zero. The simulated result shows that, compared with the conventional sliding mode observer, the parameter adaptive sliding mode observer has higher estimation precision, and the method just uses a crankshaft position sensor to get the speed signal, its hardware cost is low.