小形高速機関の始動性及び燃焼性への燃料の着火性の影響 Influence of Ignition Quality on Cold Starting and Performance for High Speed Diesel Engines
High speed diesel engines are widely used for coastal fishing boats. The problems on cold starting and white smoke emission have occurred in winter when low ignition quality fuel was supplied. Cold starting tests were carried out at a cold test facility at ambient temperatures varied from 25°C to -5°C, on the fuels of different cetane indexes and both compression ratios of 18 or 15 for a small sized direct injection diesel engine. These three factors had also adverse impact on startability and white smoke emission at cold starting of the engine. The effect that reduced the value of 5 in cetane index was equivalent to reduce the ambient temperature in 7.5°C. Cyclic white smoke formation was directly related to the variation of cyclic combustion instability during cold starting. Every cycle that fails to fire will cause the engine speed decelerating, and cause to produce white smoke. In the case of a compression ratio is 15, it should be necessary above 50 in cetane index values without the starting aids. At warmed-up operation, the engine performances were examined under different cetane index fuels with varying the fuel injection timing. The specific fuel consumption at lower loads was increased with decreasing the cetane index of fuel. However, specific fuel consumption at rated power was in agreement with each fuels of different cetane index if fuel injection timing was adjusted for optimum.
日本舶用機関学会誌 34(3), 195-203, 1999-03-01
The Japan Institute of Marine Engineering