Patent ID: 6231480
Filing Date: 2001-05-15
Classification: B60W,F16H,Y10T

Abstract:
A lockup control system for controlling engagement of a lockup clutch for a fluid coupling through which driving torques is transmitted to a transmission gear mechanism of an automatic transmission from an engine, said lockup clutch coupling an input element and an output element of said fluid coupling together while locked and releasing the input element and the output element of said fluid coupling to allow relative rotation between the input element and the output element of said fluid coupling while unlocked, said lockup control system comprising:driving condition detection means for detecting driving conditions of the vehicle including at least a slope of road on which the vehicle is traveling;lockup control means for controlling said lockup clutch in different modes including a lockup mode in which said lockup clutch is completely locked and a slip mode in which said lockup clutch is engaged but allowed to slip while said driving condition is in a predetermined range;shift control means for shifting the transmission gear mechanism into desired gears according to said driving conditions; andcontrol means for controlling said shift control means to cause a gear shift of the transmission gear mechanism to a gear which engine brake is more effective, and for controlling said lockup control means to unlock said lockup clutch to release the input element and the output element of said fluid coupling, even while said lockup control means puts said lockup clutch in said slip mode when said gear shift is caused when said driving condition detection means detects a downhill slope greater than a specific slope.