活塞式航空直喷发动机的燃烧特性

在ROTAX914化油器式活塞航空发动机的结构基础上,自主开发并研制了一台航空低压空气辅助直喷单缸试验机,开展了不同直喷控制参数包括:喷射时刻、喷射脉宽、喷射压力以及点火提前角对直喷发动机燃烧特性影响规律的研究.研究结果表明:存在一个最佳喷射开始时刻使得发动机燃烧效率最高,循环变动最低,最佳喷射开始时刻随发动机转速和负荷的增大而相应提前;降低直喷喷射脉宽和喷射压力均会引起发动机最大爆发压力和压力升高率的降低,快速燃烧期延长,燃烧循环变动增加;随着点火提前角提前,最大爆发压力和最大压力升高率增加,燃烧相位提前,循环变动降低.

Combustion characteristics for direct injection piston aviation engine

Based on the structure characteristics of the ROTAX914 carburetor piston aviation engine, a single-cylinder low pressure air-assisted direct injection aviation testing engine was developed. The influences of different controlling parameters, including injection timing, injection duration, injection pressure, ignition advance angles, on the combustion characteristics of the engine were investigated. The results show that: the engine combustion efficiency gets higher and the combustion cyclic variations get lower at the optimal start injection. With the increase of engine speed and load, the optimal start of injection is advanced accordingly. With the decrease of the direct injection duration and the injection pressure, the peak cylinder pressure and the rate of pressure rise are reduced, the rapid combustion period is extended and the combustion cyclic variations get higher. With the advancing of the ignition time, the peak cylinder pressure and the rate of pressure rise are increased, the combustion phase gets earlier and the combustion cyclic variations are reduced.