压燃式航空活塞发动机转矩与空燃比的控制

通过对压燃式航空活塞发动机的空燃比进行需求分析，采用发动机转矩需求的逆向倒推法，从螺旋桨的转矩需求倒推至发动机总转矩需求，建立转矩需求的主控通道和前导通道的控制模式，前导通道是利用微分控制的超前特性，加快转矩控制的动态响应能力。由相关转矩需求和进气量估算模块计算后，建立了最优空燃比控制的计算方程，实时计算得到对应的每循环总喷油量。在模拟保持飞机从零海拔起飞至1 890 m的发动机最大转矩输出条件下，列举了定海拔恒转速变转矩工况和定海拔发动机外特性工况的实验分析。实验结果表明：采用最优控制理论建立的空燃比控制，既保障了过量空气系数处于合理范围1.3～3.5之内，发动机的工作效果又能达到预期目标。

Control of torque and air-fuel ratio of compression-ignition aero piston engine

According to the demand analysis of air-fuel ratio of compression-ignition aero piston engine,the backward method of engine torque demand was used to reverse the torque demand of propeller to the total torque demand of engine,and the control modes of main control channel and leading channel were also established.The leading channel characteristic of differential control could accelerate the dynamic response ability of torque control.After the calculations of relevant torque demand and intake quantity estimation module, the calculation equations of optimal air-fuel ratio control were established, and the corresponding total injection quantity of each cycle was calculated in real-time.Under the condition of keeping the maximum torque output of the engine from zero altitude to 1 890 m, it was listed that the experimental analysis of constant speed and variable torque and the external characteristics of the engine at constant altitude. The experimental results showed that the air-fuel ratio control based on the optimal control theory not only ensured that the excess air coefficient was within the reasonable range of 1.3-3.5, but also achieves the expected goal of the working effects for the aero piston engine.