A LOCK-UP CLUTCH CONTROL SYSTEM FOR THE FLUID COUPLING OF AN AUTOMOTIVE AUTOMATIC TRANSMISSION

摘要

A lock-up clutch controller for the fluid coupling of an automotive automatic transmission, capable of making a lock-up clutch provided in the fluid coupling for directly coupling the input shaft and the output shaft of the fluid coupling engage or disengage smoothly responsive to an electric duty signal applied to a lock-up operation control solenoid valve. The lock-up clutch controller includes, as essential components, a lock-up clutch relay valve (a spool valve), a lock-up clutch control valve (a spool valve) and the lock-up operation control solenoid valve which operates in accordance with an electrical duty ratio signal to control the lock-up relay valve and the lock-up operation control valve so that the working fluid is supplied to the fluid coupling or the fluid coupling is drained appropriately for the smooth engagement and disengagement of the lock-up clutch. The torque of the lock-up clutch can be controlled so as to be increased or decreased gradually or maintained at a magnitude allowing slippage by applying a gradually variable electrical duty ratio signal to the lock-up operation control solenoid valve.