摘要
Comparative experiments of oil and water-cooling were performed on a 4-cylinder automotive gasoline engine and a single-cylinder direct injection Diesel engine. Measurements were made to investigate the variation of fuel consumption, combustor wall temperature and engine emissions (HC, CO, NOx and smoke) with two cooling media at steady-state conditions. Significant improvement of fuel economy was found mainly at partial load conditions with oil-cooling in comparison with the baseline waer-cooling both for the two engines. The experimental results also showed general trend of reduction in engine emissions using oil as the coolant. Measurements of wall temperature demonstrated that oil-cooling resulted in considerable increase of the combustor wall temperature and reduce of warmup period in starting process. For automotive gasoline engine, road tests indicated the same trend of fUel economy improvement with oil-cooling. The performance of the automotive oil-cooled engine was fUrther improved by internal cooling with water or methanol injection.
