汽油机三效催化转换器故障诊断模型的研究

Research on Three-Way Catalyst Fault Diagnosis Model

深入研究了汽油机三效催化转换器氧存贮故障诊断模型,该模型结构简单,适合数据实时处理,模型参数的精确估计是保证模型精度的关键。基于发动机空燃比"浓稀"法控制,监测尾气通过催化器后空燃比变化,间接估计催化器内氧存贮状态,结合加权递推最小二乘算法估计模型参数,并进行了Simulink仿真。仿真结果表明参数估计方法有效,催化器氧存贮模型具有较高的精度。

This paper studies oxygen storage fault diagnosis model of the three-way catalyst. The structure of oxygen storage model is simple, and the model is suitable for real-time data processing. The accurate estimation of model parameters can ensure the precision of the model. However catalyst oxygen storage level is hard to be measured directly by equipment, and this makes the difficulty to estimate the parameters of the model. Based on engine AFR ＂rich and lean＂ control and monitoring the AFR changing of exhaust gases passing the catalyst, the oxygen storage level can be indirectly estimated. The model parameters are estimated with recursive weighted least squares method. Model simulation results indicate that the method of parameter estimation is feasible, and the model has a high accuracy.