Under the accelerating or decelerating operation, it is demanded to improve the performance and reduce the exhaust smoke of diesel engines. Regarding the exhaust smoke regulation for a vehicle engine under transitional operation, the so-called free or controlled accelerating operation, are adopted as the simple measuring method. And the engine applied for the construction or agriculture is always operating under the load conditions of stepwise or periodical changes.
For two-stroke engines, in particular, the effects of operating conditions on the engine performance and the smoke character are unclear. In order to meet such demand, it is necessary to make clear the transitional character of each transfer element, i.e., the fuel injection system, the combustion process and the frictional loss.
Therefore, in this paper, the authors examined the effects of operating conditions on the responses of the indicated and the frictional torques and of the engine speed to the step changes of the fuel pump's rack.