Patent ID: 8682547
Filing Date: 2014-03-25
Classification: B60W,F16H

Abstract:
1. A method of controlling a gear ratio of a continuously variable transmission in a vehicle, said continuously variable transmission operable to change a rotary speed of an output shaft in relation to a rotary speed of an input shaft connected to an engine of the vehicle, said method comprising the steps of: automatically controlling an operation of a starting clutch according to an engine rotary speed; said starting clutch and said continuously variable transmission being connected in series between a crankshaft of said engine and said output shaft; computing a target engine rotary speed from sensed data comprising a present vehicle speed and a throttle opening; and controlling a gear ratio in said continuously variable transmission based on said computed target engine rotary speed; wherein at an engine rotary speed corresponding to a partially engaged state of said starting clutch, a target gear ratio control of said continuously variable transmission is performed by determining a target gear ratio from said target engine rotary speed, wherein said target gear ratio is set to a gear ratio corresponding to a gear ratio position between a LOW position and a HIGH position, and said target gear ratio is determined by multiplying a gear ratio for obtaining said target engine rotary speed by a constant of not more than 1, wherein said constant is obtained based on said vehicle speed and a gear ratio map; and wherein at an engine rotary speed corresponding to a fully engaged state of said starting clutch, the gear ratio is controlled such that said engine rotary speed converges with said target engine rotary speed.