In a four-cycle, naturally aspirated, pre-chamber diesel engine, the combustion characteristics such as the rates of fuel injection, the ignition lag, the rates of heat release, the combustion peak pressure, the maximum rates of pressure rise, and the smoke density, were investigated for over 70 consecutive cycles under acceleration, with the aid of an on-line data handling system developed for this experiment.
The effects of operating conditions such as the fuel injection timing, the fuel spray angle, the wall temperature of the combustion chamber, and the coolant temperature, on the combustion characteristics were also investigated.
As a result, it was clarified that the fuel injection timing as well as the coolant temperature were important factors for improving the acceleration; the combustion characteristics during the acceleration except for the time just after the beginning of acceleration were estimated from the data obtained for steady-state operation corresponding to acceleration.