Firing behavior of spark-ignition engine fueled with different fuels during cold start

The transient firing behavior of a spark-ignition engine fueled with gasoline, liquid petroleum gas (LPG) and methanol respectively during cold start was investigated experimentally by means of cycle-by-cycle control strategy on a 125 mL-single-cylinder four-stroke electronically controlled fuel injection engine. The amount of fuel injected per cycle and the ambient temperature for assuring gasoline, LPG and methanol engine reliable start were investigated experimentally based on the single cycle fuel injection. The results show that the amount of fuel injected per cycle significantly affects gasoline and LPG engine cold start reliability. A proper amount of fuel injected per cycle can ensure a reliable start of gasoline and LPG engine. The ambient temperature affects methanol engine reliable cold start the most significandy, and the amount of methanol injected per cycle takes the second place. When the ambient temperature is below 16C, the methanol engine cannot be started reliably without auxiliary start-aids even with the large amount of methanol injected per cycle under low injection pressure. At the same injection timing, gasoline and LPG engine may realize the ideal firing of next cycle combustion after fuel injection, and the firing of methanol engine is one cycle later than that of gasoline and LPG engine.