大功率天然气发动机怠速控制策略研究

Study on Idle Control Strategy of High-Power Natural Gas Engine

为提高大功率天然气发动机怠速时的稳态和动态效果,以V模式为研究手段,基于一款六缸天然气多点电喷发动机,实现了发动机怠速控制策;首先针对不同的怠速工况设计了不同的目标怠速转速值的计算,并根据发动机特性确定了PI控制模式;利用目标怠速转速和瞬时转速的差值确定不同PI控制参数,通过PI控制调节电子节气门的开度,从而实现对发动机怠速转速的控制;然后根据实际发动机参数搭建了发动机MATLAB/SIMULINK仿真模型,用于对怠速控制策略进行软件在环仿真测试以及PI控制参数预标定;最后在天然气发动机试验台架上对控制策略进行了进一步的试验和标定;试验结果表明:该怠速控制策略,可让发动机转速响应时间控制在1秒左右,转速稳定时间在2秒左右,发动机转速稳态误差控制在±5rpm范围之内,实现了对怠速的良好稳定控制。

To improve the stable and dynamic characteristic of high--power natural gas engine idle speed, an idle speed control strategy was accomplished by V--model based on a six--cylinder natural gas engine with electric controlled multi--point injection system. First, the target idle speed was designed to be calculated in different ways according to different engine working conditions, and PI control was deter- mined by engine characteristics. In order to realize an excellent control effect, the electronic throttle angle was controlled by different PI con- trol parameters which was looked up by the difference between target idle speed and engine transient speed. Then, using the software MAT- LAB/SIMULINK, a simulation engine model was set up based on the test engine which was used for software in the loop test of idle control strategy and for pre--calibration. Finally, the idle control strategy was further verified and calibrated by engine bench test. The test result shows that; the responding speed of engine speed is about ls, the transient time is about 2 s, and the steady state error is less than ±5r/ min, which has an excellent control on the test engine by the idle speed control strategy.