VVA汽油机进气道燃油观测器的研究

Study on Observer of Fuel Dynamics in Intake Port of SI Engines Equipped with Fully Variable Valve System

为了满足全可变气门驱动(VVA)汽油机空燃比控制的要求,研究了其进气道的油膜动态特性,建立了最小二乘辨识递推模型。通过在误差函数中加入指数权项,加重了对较新数据的重视程度,提高了油膜动态参数的跟踪能力,实现了进气道燃油动态参数的在线辨识。此外,针对进气传输和传感器惯性所引起的滞后,建立具有新陈代谢功能的GM(1,1)进气预测模型,并利用新测得的数据对模型进行修正。试验结果表明,基于灰色预测模型和最小二乘递推算法的燃油观测器在实时性和精确性方面效果明显,能够为空燃比的精确控制提供理论指导。

To meet the requirements of air-fuel ratio adaptive control for VVA（fully variable valve actuation）gasoline engine,the dynamic characteristics of fuel film in the intake port were studied and the recursive least squares identification model was established.By adding exponent factors into the error function of identification model,the new data is treated as highly emphasized,and tracking capability of the film dynamic parameters is enhanced,realizing real-time on-line identification on the dynamic characteristics of fuel film in intake port.The intake mass and air-fuel ratio transporting characteristic was investigated,and the GM（1,1）prediction model with a metabolic function was established to solve the lag of intake mass caused by transportation and the inertia of sensor,which was modified by the new data measured.Test results show that the fuel state observer based on the recursive least squares identification arithmetic has good performance in accuracy and real-timing.It provides the theoretical guidance in the accurate air-fuel ratio control.