독일 압력제어방식 CVT의 압력전동 감소 연구

In this paper, pressure characteristics for an independent pressure control type CVT are investigated, and (j solution to reduce the pressure fluctuation at steady state is proposed. From the experiments, a pressure fluctuation is observed at some secondary pressure range. In order to analyze the pressure characteristics, dynamic models of the hydraulic control system including the CVT variator are obtained. Using the dynamic models, the parameters that affect the pressure fluctuation are investigated. From the simulations, it is found that the change of the hydraulic stiffness is the main reason for the pressure fluctuation. Modification of the notch area of the SCV supply p0l1 is proposed to decrease the hydraulic stiffness gradient of the supply line from the SCV to the CVT variator. From the simulation and the experiment, it is found that the pressure fluctuation can be reduced effectively by the hydraulic stiffness control.