A Study on the Dynamic Characteristic of a Small Two-Stroke Cycle Diesel Engine : Characteristic of Free Acceleration

In order to make clear the response of engine speed to the change of brake load and the abnormal exhaust smoke under free accelerating operations, the authors carried out some experiments. The results obtained are summarized as follows: (1) The change of engine speed in the first half of accelerating period corresponds nearly to the characteristic of 1st order lag element and its time constant depends mainly on the characters of indicated torque, frictional torque and the inertia moment of revolving part in engine. Moreover, it is possible to make clear analytically the effects of various operating conditions on the time constant. (2) The abnormal exhaust smoke density under free accelerating operations increases nearly in proportion to the mean accelerating engine speed so that it depends on the initial conditions of engine speed, flow rate of injecting fuel, intake air capacity and temperature of combustion chamber wall etc.