Abstract
Keywords- CVT, HEV, Starting Clutch, Hydraulic Control System, Limp-Home
The CVT for hybrid electric vehicle application using multi disc wet clutches as a starting device requires that a new concept hydraulic control system to be developed in order to improve cooling performance of the starting clutches and to be developed for hydraulic limp-home function. Accordingly, the cooling and lubrication system of the CVT for hybrid electric vehicle application has been developed. Also, the new concept hydraulic control system that controls clutch pressure according to the engine speed even in the situation of TCU malfunction was developed. This paper presents a new concept CVT hydraulic control system for mild HEV application. The hydraulic control system composes of 4 functional parts.
- Belt and pulley pressure control part which provides belt clamping force and speed ratio control
- Starting clutch control part including forward/reverse reversal as well as cooling and lubrication flow control
- Whole CVT cooling and lubrication system including belt and pulley
- Hydraulic limp-home function parts