汽油机进气道油膜动力学模型参数辨识  

Parameter Identification of Intake Port Fuel Film Dynamic Model for Gasoline Engine

作　　者：郑太雄[1] 周可君 李永福[2] 李宣政 

机构地区：[1]重庆邮电大学先进制造学院,重庆400065 [2]重庆邮电大学自动化学院,重庆400065

出　　处：《农业机械学报》2015年第4期296-301,共6页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金资助项目(61304197);重庆市教委科学技术研究资助项目(KJ130506);重庆邮电大学青年基金资助项目(A2012-78)

摘　　要：为了更加精确地辨识汽油机进气道油膜模型参数,从而更加精确地控制空燃比,在油膜动力学模型的基础上,考虑模型误差和随机误差,建立了油膜辨识方程。根据递推最小二乘算法得到油膜参数估计的加权矩阵表达式,利用马尔可夫估计得到该加权矩阵,进而得到油膜参数的最优估计。应用GT-power建立了发动机模型,在转速1 000～3 500 r/min、节气门开度5%～75%变化时,分别利用提出的算法和最小二乘法对油膜参数进行了辨识,并与标定值进行了比较。结果表明,燃油沉积系数X在同一转速时,随着节气门开度的增大而减小,在同一节气门开度时,随着转速的增加而减小;油膜质量蒸发时间常数τ在同一转速时,随着节气门开度的增大而增加;在同一节气门开度时,随着转速的增加而减小。通过误差分析,表明所提出的方法比最小二乘算法的辨识结果精度更高。Accurate air-fuel ratio control is the key element for fuel economy low emissions and good driveability of spark ingnition engine. In order to more accurately identify the fuel film model parameter and achieve precise control of air-fuel ratio, the film identification equation based on fuel film dynamic model was built under the consideration of model error and random error. According to recursive least squares, the parameter estimation with weighted matrix expression was got, then the weighted matrix was solved using Markov estimation and the estimated value of optimal film parameter was got consequently. An engine model was set up using GT-power, and air fuel ratio, mass injection flow engine speed and air mass flow were obtained by using sampling experiment. Parameter identification applying the proposed algorithm and the least squares were conducted at 1 000 -3 500 r/min with throttle opened from 5% - 75% , respectively. Meanwhile, the identification results were compared with the calibration value. The results showed that the deposition coefficient X of fuel reduced and evaporation time constant of film quality increased with increase of throttle opening degree when speed was the same, and X z decreased as speed increasing when throttle opening degree was the same. Compared with the least squares algorithm, more accurate identification result can be got by using the proposed algorithm.

关 键 词：发动机 油膜模型 参数辨识 递推最小二乘算法 马尔可夫估计 

分 类 号：TK417[动力工程及工程热物理—动力机械及工程]