Mathematical modeling and performance prediction of a clutch actuator for heavy-duty automatic transmission vehicles

Abstract With regard to heavy-duty automatic transmission vehicles, precise control and fast response of clutch pressure, as well as transient high flow capacity, are central to shifting performance. In order to reduce fuel consumption and improve shift quality, a novel mathematical model for electro-hydraulic actuator used in heavy-duty automatic transmission is proposed to predict the response performance of a wet clutch in this paper. Firstly, the governing equations of a proportional solenoid valve (PSV) excited by the current of pulse width modulation (PWM), a pressure reducing valve (PRV) pilot operated by PSV and a simplified clutch model are derived by means of integration technology. Moreover the transfer function of PRV to the clutch is deduced to draw Bode plots. Then, the experimental date obtained from a real test bench is compared with the numerical results to validate the applicability of the mathematical model. Finally, simulations are performed on the forces, displacement, velocity, flow rate, clutch pressure, pressure deviation, response deviation and flow force. Numerical results indicate that the proposed model is valuable for the performance analysis and optimization of clutch actuator.