面向控制的柴油机进排气氧气质量分数估计方法研究

在构建高压回路EGR涡轮增压柴油机气路系统动态模型基础上,设计了柴油机进排气氧气质量分数的龙贝格观测器,实现对柴油机进排气氧气质量分数的估计;利用李雅普诺夫稳定性原理对设计的观测器进行了稳定性分析,分析结果显示,设计的进排气氧气质量分数观测器满足稳定性要求,可以用于进排气氧气质量分数的估计;由于进气歧管不宜安装宽裕氧传感器(UEGO),进气氧气质量分数难以测到,本文推导出一种进气氧气质量分数的计算方法,并对推导出的计算方法进行了仿真对比验证,结果表明,该计算方法能够对进气氧气质量分数进行比较精确的计算估计;最后,对设计的进排气氧气质量分数观测器进行了仿真和试验验证,结果表明,设计的观测器可以对柴油机的进排气氧气质量分数进行准确估计,为基于进排气氧气质量分数的柴油机气路控制器设计奠定了基础。

Control Oriented Research on Method of Intake and Exhaust Oxygen Mass Fraction Estimation for Diesel Engine

An innovative oxygen mass fraction estimation method for turbocharged diesel engine was described. Based on the dynamic model of turbocharged diesel engine with high pressure exhaust gas recirculation (EGR), the Luenberger observer of the intake and exhaust oxygen mass fraction was developed. By using the data acquired from the standard sensors equipped on the engine, the intake and exhaust oxygen mass fraction can be estimated by using the Luenberger observer. The convergence stability of the observer was proved through a Lyapunov analysis, the results show that the observer can meet the stability requirements. It can be used for estimating the intake and exhaust oxygen mass fraction. For various reasons, it is not suitable to install universal exhaust gas oxygen (UEGO) sensor on the intake manifold; the intake oxygen mass fraction needs to be obtained by other means. The calculated algorithm of the intake oxygen mass fraction was proposed and the method was verified by using the GT Power simulation data. The maximum error was less than 1.3%, the results show that the calculation method was able to accurately calculate the intake oxygen mass fraction. Finally, the test bench of the YC4E170-31 diesel engine was built. The exhaust oxygen fraction can be calculated by using the UEGO sensor which was installed at the exhaust manifold. The observer of the intake and exhaust oxygen mass fraction was verified against the experimental data and simulation data, the results show that the observer can accurately estimate the intake and exhaust oxygen mass fraction, and the estimation error was in a reasonable range, which laid a foundation for air path controller design based on intake and exhaust oxygen mass fraction.