Dry Dual Clutch Torque Model with Temperature and Slip Speed Effects
Dry dual clutches are widely used in automated manual transmissions. In such systems the clutch engagement maneuvers require a precise knowledge of the characteristics that relate the frictional torque transmitted by the clutches with the corresponding actuators variables. In this paper a temperature and slip speed dependent model of the torque characteristic for dry dual clutches is proposed. Dynamic models of the temperature evolution are determined and linked to the characteristics of the mechanical components influencing the torque. The models, whose parameters are tuned with dedicated experiments and realistic data coming from an industrial automotive environment, show the temperature influence on the torque transmitted by the clutch. Real time simulation results, obtained through a detailed software in the loop driveline model, show that, if not compensated, the temperature variation can determine critical degradations of the clutch engagement performances. It is shown how the use of the clutch temperature estimation in the torque transmissibility model allows to compensate for such negative effects. The torque model is also exploited for the realization of a decoupling clutch engagement controller. The corresponding closed loop results show the effectiveness of the proposed compensations for the dependencies of the clutch torque on temperature and slip speed.