Studies on combustion of residual fuel sprays in a diesel engine with the aid of visualization method

To improve the burning condition of the residual fuel in the combustion chamber of a diesel engine, visualization and combustion diagnosis of the residual fuel spray were carried out. First, the effects of some physical means such as the impingement of spray on the combustion chamber wall and the air-swirl were verified. Next, the effects of increase of air temperature in the combustion chamber on the ignition delay and combustion condition were examined. As a result, it was made clear that some means to improve the evaporation rate would be necessary for the residual fuel spray. As it would be very difficult to improve the evaporation rate of residual components themselves, it is considered to be a realistic means to accelerate the evaporation of distillate components in the residual fuel and promote the combustion of residual components.