Abstract: The unregulated emissions were measured on a chassis dynamometer for a light-duty vehicle fuelled with pure gasoline,  fuels with the volume proportions of methanol are 10%, 20% and 30% in the methanol-gasoline blends, before and after conventional three-way catalyst (TWC) using a FTIR spectrometer. The measured results show that the regulated emissions such as CO, HC and NOx of low-proportion (≤30%) methanol- gasoline blends, are the same level as those of pure gasoline under both 25 °C and -7°C cold start. The unregulated emissions, such as unburned methanol and formaldehyde, before the catalyst increase with the increase of methanol proportion. However, the unburned methanol and formaldehyde have very high conversion efficiency and are near zero once the catalyst is lit off.

Key words: light-duty vehicle, methanol-gasoline blends, cold start, unregulated emissions