The Two-Mass Flywheel - A Torsional Vibration Damper for the Power Train of Passenger Cars - State of the Art and Further Technical Development

The rotational irregularities of an engine, which are primarily caused by the forces generated by the combustion gases during the periodic combustion process, are transmitted to the driveline and there lead to vibration and noise. Since 1985, BMW has been using its two-mass fly-wheel on certain gasoline and diesel engines. This is a mechanical low-pass filter, which largely isolates rotational irregularities and vibration from the complete driveline and therefore reduces the noise level inside the vehicle. Running speeds significantly exceeding 5000 rpm however cause a severe increase in wear on the internal components of the torsional vibration damper, as a consequence of the higher centrifugal forces. For use of the two-mass flywheel at very high engine speeds, more satisfactory tribological conditions have therefore to be created. Closed systems filled with a medium with a simultaneous lubricating and damping effect are currently being investigated, and test results so far have been promising.