INTRODUCTION OF THE LATEST HYDRAULIC CONTROL SYSTEM FOR AUTOMATIC TRANSMISSION

Abstract

From the social background of global warming issue, earth environment protection issue and the rise of oil price, the demand of the improvement of fuel economy and CO2 reduction to a vehicle is very high nowadays. Continuously variable transmission (CVT) adoption has been recently increased to respond such social demand. JATCO is now also expanding the lineup of CVT as new solution for vehicle automatic transmission. In CVT, the shift control hydraulic pressure is a little bit higher than that of conventional stepwise shifting automatic transmission. So, unstable behavior of pressure is sometimes caused, for example, pressure oscillation. Such issue should be solved in early development stage. In this paper, we would like to introduce the feature and the techniques of oil pressure control system of CVT as an example of latest hydraulic control system for automatic transmission. And we would like to introduce our recent simulation for the optimal design of hydraulic control system.