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The paper presents a diaphragm spring clutch linear thermal model. The main model aim was to estimate the temperature on the clutch disc slipping surfaces. That objective was pursued through a linear model to overcome the memory and computing time problems required by models with a more complex structure. The model parameters were experimentally identified. The model was validated employing a test bench, considering shift transient different as far as energy dissipated, clutch disc wear, frequency of shifting, gearbox temperature. The model structure, the methodology adopted to identify the model parameters, the experimental results obtained are presented and discussed.

New engine control strategies, designed for drive-by-wire systems, will require the measurement (or the estimation) of several operative engine parameters in order to control emissions and efficiency, while satisfying the driver demand in terms of driveability and performance. Both load and indicated torque (i.e. the torque due to the gas pressure acting on the pistons) will play an essential role in this context, since the driver pedal command may be appropriately interpreted by the Electronic Control Unit (ECU) in terms of an engine (or load) torque request. In fact, the accelerator pedal variation forces the vehicle to reach a final steady-state condition, corresponding to a new level of engine and load torques, thus making it possible to assume the existence of a direct link between the pedal position and the “desired” final engine (or load) torque.