Motorless pilot studies of crankshaft dampers of combustion engines

This article is about motorless studies of crankshaft dampers of combustion engines. An option to reduce the adverse effect of torsional motions of the crankshaft to the working life and effective performance of the engine is the dampers’ installation. However, dampers’ installation causes a change in the number of motor masses, what in turn results in a change in free frequency. As a consequence, there are changes in the resonant modes of operation, and ones in the type and shape of the constrained oscillations. To ensure the efficient operation of the recently designed construction of dampers, numerous final tests have to be performed, and the calculation itself is iterative, which considerably increases the complexity and a number of calculations. Stand design is suggested for carrying out these researches in a motorless way, while the modes and parameters of the torsional motions of the crankshaft match the operating modes of the combustion engine itself. Changeability of the distance between the motor masses and the type and magnitude of the torques acting on the motor masses makes the suggested stand universal for testing engines of any layout diagram. Torque modulation in amplitude, frequency, and phase is obtained by changing the appropriate electrical settings on the stator windings, creating torque for an equal torsional circuit. This circuit also enables testing only for resonant torque harmonics, which is an unquestionable advantage of the offered stand.