Performance and Emission Measurement of Spark Ignition Engines Operating with 100% Methanol Fuel

A small two-wheeler engine and a large, multi-cylinder bus engine are demonstrated for 100% methanol operation and, performance and emissions with methanol are compared to baseline. This kind of study on both small and large engines operating with 100% methanol is not reported in the literature as per the authors' knowledge. A high flow injector is incorporated for the small engine for methanol. The fuel-air ratio is adjusted to operate the engine around a Lambda value of 1, and ignition timing is optimized to achieve maximum torque. Finer adjustments to Lambda are performed to maintain the nitrogen oxides emission less than that of the gasoline engine. The torque at wide-open throttle is higher than that of gasoline, around 5% higher brake thermal efficiency, and lower or similar regulated emissions are observed with methanol. For the large engine, a liquid nozzle and an electric fuel-pump are incorporated for methanol. Lambda is maintained around 1, and ignition timing is optimized for maximum brake torque while avoiding knocking. The rated torque and power are achieved with around 50% throttle opening, 3% higher brake-thermal efficiency, and lower nitrogen oxides are observed with methanol.