点火和喷射正时对甲醇发动机冷起动非常规排放的影响

基于单循环甲醇喷射策略在一台125mL单缸四行程电控喷射点燃式甲醇发动机上试验研究了点火正时和甲醇喷射正时对甲醇发动机冷起动瞬态工况非常规排放(甲醛和未燃甲醇排放)的影响。试验结果表明,点火正时和甲醇喷射正时显著影响甲醇发动机冷起动工况的甲醛和未燃甲醇的排放。-20°CA ATDC点火和471°CA ATDC喷射甲醇时,发动机着火性能最好,气缸压力最高,未燃甲醇排放最低,甲醛排放最高。甲醇发动机冷起动工况甲醛和未燃甲醇的排放随点火正时、甲醇喷射正时的变化呈相反的变化趋势。

Effects of ignition and methanol injection timing on unregulated exhaust emissions from methanol engine during cold start

The effects of ignition timing and methanol injection timing on unregulated exhaust emissions (formaldehyde and unburned methanol emissions) of the methanol engine during cold start were investigated experimentally using a single-cycle methanol injection strategy on a 125 mL single-cylinder four-stroke electronically controlled fuel injection spark-ignition engine. The results showed that the ignition timing and the methanol injection timing affect the formaldehyde and the unburned methanol emissions significantly. At the ignition timing of -20 °CA ATDC and the methanol injection timing of 471 °CA ATDC, the firing performance of methanol engine is the best, the in-cylinder pressure is the highest, the unburned methanol emission is the lowest and the formaldehyde emission is the highest. The variations in emitted formaldehyde and unburned methanol show opposite tendencies with the variations in the ignition timing and the methanol injection timing.