ディーゼル機関のアルコールブレントおよびフューミゲーションにおける着火遅れ

Abstract

The effects of temperature and pressure on the ignition delay for alcohol blends and fumigation were studied in a constant volume combustion bomb and a diesel engine. In the experiment using the bomb, the effect of blending ethanol with a diesel fuel (DF2) on the ignition delay was investigated. The test covered the whole mixing range of ethanol-DF2 blends. The ignition delay for the fumigation of methanol or the diesel fuel was measured in a DI. diesel engine. The test parameters were ; fuel quantity fumigated into an inlet pipe, intake air temperature, and injection timing of the diesel fuel from a main nozzle. The cylinder temperature in the engine was measured by a fine thermocouple with a compensation circuit under the motored condition. Single shot injection was adopted to reduce residual gas from a previous cycle. The measured results showed that, for the ethanol-DF2 blends, the ignition delay increased by increasing the ethanol content in the blends. For the fumigation method, the ignition delay decreased by increasing the quantity of the fuel fumigated into the inlet pipe, and the tendency became larger at the low cylinder temperature. Methanol fumigation showed a larger effect on the ignition delay than the diesel fuel fumigation.