Problems with determination of instantaneous values of torque generated by a combustion engine

By its nature an internal combustion engine is a machine that transmits a variable torque to the power receiver. Engine of less cylinders performs greater variations of torque within the work cycle. Both value and direction of the torque change themselves. Especially the change of direction is important because of clearances in the drive chain. Definition of the specific tangential force, the quantity directly affecting the torque generated by the engine belongs to the basic tasks during engine design process. The specific tangential force graph is being computed ignoring vibrations in the engine–power receiver set. It is a quite substantial simplification which leads to results that could not be confirmed in a course of experiments. The following paper presents diagrams of the tangential force variations obtained in a course of measurements, calculations and computations taking into account the elasticity of drive chain. Results of efforts described in this paper brought about the development of a measuring–computational method which allows to determine the engine generated torque with sufficient accuracy. It is possible to determine this torque on the ground of measured engine to a power receiver coupling torque and the instantaneous value of angular velocity of both engine shaft and the shaft of power receiver.