Method of controlling clutch pressure of continuously variable

Abstract

A method of controlling clutch pressure in a continuously variable transmission system which can expand and contract the width of a channel between a stationary pulley member and a movable pulley member movable relative to the stationary pulley member in order to respectively contract and expand a radius of travel about the pulleys of a belt engaging the pulleys before eventually varying a belt ratio, a clutch-pressure control arrangement of the continuously variable transmission system including a controller unit which effects control by feeding an actually-detected clutch pressure back in determining an objective clutch pressure and including an oil-pressure circuit which controls oil pressure in response to signals from the controller unit; the method comprising the step of: causing the controller unit to calculate a clutch duty ratio in reference to the objective clutch pressure and an objective line pressure when a pressure sensor detecting the actually-detected clutch pressure outputs an abnormal signal before eventually causing the controller unit to control the clutch pressure in accordance with the calculated clutch duty ratio.