点燃式甲醇发动机冷启动临界着火边界

Investigation of critical firing boundary of spark ignition methanol engine during cold start

针对点燃式甲醇发动机低温下启动困难,基于单循环燃料喷射策略试验研究了甲醇最小循环喷射量、环境温度、预热和进气道内喷射液化石油气(LPG)等参数对甲醇发动机冷启动临界着火边界的影响。试验结果表明:甲醇最小循环喷射量、环境温度、甲醇喷射正时和点火正时角度差、预热和气道内喷射LPG量及甲醇和LPG喷射正时角度差决定甲醇发动机冷启动的临界着火边界;环境温度低于16℃时,甲醇发动机必须使用辅助启动措施方可启动;电热塞预热可使甲醇发动机在0℃以上环境温度下启动;喷射LPG可使甲醇发动机在-13℃以上环境温度下启动。

To overcome the difficulty of cold start of spark methanol engine at low ambient temperature,the effects of the minimum amount of methanol injected per cycle,the ambient temperature,the angle difference between injection timing and ignition timing,preheating method and additional LPG injected into the inlet port on the critical firing boundary of the engine based on single cycle duel injection were investigated by experiments.Results show that the critical firing boundary is influenced by all the above factors,and by the angle difference between methanol injection timing and LPG injection timing.When the ambient temperature is below 16℃,an auxiliary start-aid must be used to support the cold start of the methanol engine.Glow plug preheating can ensure reliable firing of the methanol engine at ambient temperature above 0℃.Using an additional auxiliary start-aid,injecting LPG into the inlet port,can result in reliable firing at ambient temperature above-13℃.