Abstract:

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.

Key words: power machinery and engineering, methanol engine, ignition timing, methanol injection timing, cold start, unregulated exhaust emission