液力缓速器压力油箱动态充液过程制动转矩特性

Hydrodynamic retarder plays a key role in the driving assist braking system,and the main challenge it faces is the problem of rapid response and accurate prediction of braking torque. To achieve rapid onset,a pressure tank is used to accelerate oil-filling for a heavy equipment,but the changes in tank pressure and wheel speed during the oil-filling process will dynamically affect the filling flow rate and braking torque. Therefore, this paper constructs a prediction model for the oil-filling process of the hydraulic retarded braking system considering the pressure tank,realizes the two-way dynamic update of the boundary conditions of flow parameters at the inlet and outlet of wheel cavity,and deeply explores the hydrodynamic-hydraulic coupling relationship between the wheel cavity system and the charging and discharging control system. The simulated and experimental results show that the prediction error of the proposed model for peak torque is 15. 61%,and the response time error is 15. 04%,which verifies that the proposed model is capable of effectively exploring the braking characteristics of hydraulic retarder under the condition of fuel supply from the pressure tank for actual vehicle. The influence of the pressure tank characteristics on the braking torque characteristics at a given inertia and initial speed is further analyzed, and the regulation mechanism of the pressure tank parameters on the dynamic process of oil-filling is clarified.