汽油机非线性卡尔曼滤波暂态进气量估计及空燃比控制

暂态工况下缸进气量的准确估计是提高发动机空燃比控制精度的有效措施之一,为此本文提出一种基于无迹卡尔曼滤波的暂态缸进气量估计算法,并利用估计的缸进气量设计了一种前馈-反馈空燃比控制器.MATLAB环境下的仿真实验给出了所提出的算法与现有进气量估计算法的比较,同时基于暂态气量估计的空燃比控制仿真实验验证了估计的有效性.论文与现有成果的区别在于:一是暂态进气量估计模型不仅包含了歧管压力动态还考虑了曲轴角速度动态,并采用了基于非线性辨识的均值模型;二是考虑了泵气波动的影响,采用了移动平均值法的数字滤波器对泵气波动进行滤波;三是采用无迹卡尔曼滤波算法对歧管压力和曲轴角速度进行估计.

Transient cylinder air charge estimation with nonlinear Kalman filter for air-fuel ratio control of gasoline engines

Since accurate estimation for transient cylinder air charge is an effective method for improving the accuracy of transient air-fuel ratio control of engine, an estimation algorithm based on unscented Kalman filter is proposed for the transient cylinder air charge. Furthermore, a feedforward-feedback controller of the air-fuel ratio is designed by utilizing the estimated cylinder air charge. Simulation comparison in MATLAB is given with the existing estimation algorithm for the cylinder air charge. Meanwhile, the effectiveness of the proposed estimation algorithm is validated by simulation illustration of air-fuel ratio control based on the estimated transient cylinder air charge. The difference from the existing results lies in three aspects: firstly, the estimation model for transient cylinder air charge, which includes the crankshaft rotation velocity dynamic besides the intake manifold pressure dynamic and also is described as the mean-value model obtained by nonlinear identification, secondly, the utilization of digital filter with moving average for dealing with the pumping fluctuations, and finally, the adoption of unscented Kalman filter for estimating the intake manifold pressure and crankshaft rotation velocity.