环境温度对点燃式甲醇发动机冷起动性能的影响

基于循环控制试验研究了环境温度对电控喷射点燃式甲醇发动机首循环起动着火特性和HC排放的影响。结果表明,环境温度对该发动机起动着火特性有显著影响。环境温度低于16℃时,不采取辅助起动方法,无论首循环喷射多少甲醇燃料,也无法使点燃式甲醇发动机起动。采用电热塞预热进气管和进气道喷射适量LPG均可使甲醇发动机低温下可靠起动,实现理想的"即喷即着"的首循环着火。环境温度显著影响甲醇发动机冷起动时燃料蒸发速度和混合气浓度。环境温度升高,甲醇发动机首循环可靠起动的喷射脉宽减小,起动性能改善。

Effect of ambient temperature on cold start behavior of S.I.methanol engine

The effects of the ambient temperature on the cold start behavior and the HC emission of an electronically controlled inlet port methanol injection S.I.engine were investigated by means of the single-cycle fuel injection strategy.The results show that the ambient temperature affects significantly the start firing behavior of the engine.When the ambient temperature is below 16 ℃,the methanol engine can not be started without the auxiliary start-aids even at high single cycle methanol injection.Using a glow-plug to heat the engine inlet manifold and additional LPG injected into the inlet port result in a reliable firing of the engine,and the ideal concept of "next cycle combustion after fuel injection" may be realized at the cold start.The ambient temperature is closely related to the fuel vaporization and fuel-air mixture formation,especially at the cold start.The methanol injection amount per cycle sufficient for the reliable firing during the cold start of the engine reduces obviously and the cold start performance improves significantly with a rise in ambient temperature.