Multidimensional Predictions of Methanol Combustion in a High-Compression DI Engine

Numerical simulations of lean Methanol combustion in a four-stroke internal combustion engine were conducted on a high-compression ratio engine. The engine had a removable integral injector ignition source insert that allowed changing the head dome volume, and the location of the spark plug relative to the fuel injector. It had two intake valves and two exhaust ports. The intake ports were designed so the airflow into the engine exhibited no tumble or swirl motions in the cylinder.

Three different engine configurations were considered: One configuration had a flat head and piston, and the other two had a hemispherical combustion chamber in the cylinder head and a hemispherical bowl in the piston, with different volumes. The relative equivalence ratio (Lambda), injection timing and ignition timing were varied to determine the operating range for each configuration. Lambda (λ) values from 1.5 to 2.75 were considered. The results showed that the highest temperature and pressure were achieved with λ=1.5, and the minimum temperature and pressure occurred for λ=2.75. In addition, the configurations that had a head dome and a piston bowl produced higher temperatures and pressures in the cylinder.