In this paper, a 4 cylinder SI engine was fuelled with gasoline, M10, M30 and M85 methanol-gasoline blends, and the cold start transient performances were investigated under the ambient temperature of 15°C, -7°C, -15°C and-25°C, respectively. The engine speed curves indicate the existence of misfire and incomplete combustion, which are proved by the measured temperatures and the indicated mean effective pressure (IMEP) obtained from the cylinder pressure analyses. The addition of methanol increases the starting time at low temperature, but improves the combustion. The peak speed and the transient period increase with the increase of methanol fraction, while the speed fluctuation decreases.
