Modelling of an automotive dual mass flywheel

Abstract

Accurate knowledge of the instantaneous friction torque of an automotive clutch is a key claim while achieving comfortable, automated gearshifts, improving fuel economy or reducing wear. Nevertheless, torque sensors are not commonly used in automotive drive trains because of their additional size and costs. Thus, to estimate the clutch torque, a detailed dynamic model of each component integrated into a clutch system is needed.In the following, a nonlinear dynamic model of a Dual Mass Flywheel (DMF) as autonomous part of a clutch system is presented and verified by test bench data. A DMF is used to reduce the cyclic irregularity of the torque generated by a combustion engine. It is typically assembled between crankshaft and clutch. The level of detail of the modelled DMF dynamics is chosen in a way that a real-time simulation on a car's control unit is feasible. Using the engine speed and the clutch torque as model inputs, the proposed model has the ability to simulate the DMF deflection and therefore the clutch rotational speed. Resulting torques acting on the DMF's primary and secondary mass are reconstructed, too. If both rotation speeds of the DMF masses (the engine and clutch speed) can be measured, this model can also be used to reconstruct the clutch torque.