针对甲醇发动机低温冷起动困难，在一台由1130单缸柴油机改造的直喷火花点火甲醇发动机上，利用商用CFD模拟软件AVLFire耦合甲醇氧化反应机理，通过电热塞将进气温度加热到283 K，研究了喷射时刻对甲醇发动机低温（266 K）冷起动燃烧及非法规排放的影响。结果表明：推迟喷射时刻能够改善缸内燃烧，使得缸内混合气能够得到较为充分燃烧，减小未燃甲醇排放，当喷射时刻由53°BTDC推迟到49°BTDC时，未燃甲醇排放显著减少；喷射时刻由57°BTDC推迟到49°BTDC时，甲醛排放增大，但当喷射时刻继续推迟到45°BTDC时，缸内最高燃烧温度超过1 200 K，使得甲醛快速氧化，甲醛排放显著减少。

For the problem of difficult cold start of methanol engine in low temperature, the effects of injection timing on low temperature combustion after cold start and unregulated emission were studied on a direct injection spark ignition methanol engine retrofitted from an 1130 single cylinder diesel engine by heating intake temperature to 283 K from 266 K based on CFD AVLFire coupling chemical kinetics reaction mechanism simulation. The simulation results show that retarding the injection timing can improve the incylinder combustion and reduce the unburned methanol emission due to the complete combustion of incylinder mixture. When the injection timing retards from 53°BTDC to 49°BTDC, the unburned methanol emission reduces remarkably. In addition, the formaldehyde emission increases when injection timing retards from 57°BTDC to 49°BTDC, but when it continues to retard to 45°BTDC, the combustion temperature exceeds 1 200 K so that the formaldehyde oxidizes rapidly and its emission becomes less obviously .