Abstract
A fully electro-hydraulic controlled rig type metal belt CVT system was developed by using 3-way PWM high speed solenoid valves. For the optimal operation of engine, 3-D speed ratio map and shifting algorithm of CVT were derived. In addition,a 2-D optimal line pressure map was suggested for the improved hydraulic system efficiency. Experimental results using the shifting algorithm and control strategy showed that the PWM electro-hydraulic CVT system developed in this study made the engine remain on the optimal operation line for various changes of the throttle opening.