Neutral idle control mechanism for a torque-transmitting clutch in a power transmission

摘要

A control for a power transmission has a neutral idle circuit comprised of a signal valve, a control valve and a shuttle valve. The signal valve supplies a bias pressure to the control valve, which has an output control pressure proportional to the input torque to the transmission. The output control pressure and transmission line pressure act on the shuttle valve to direct the control pressure to a clutch in the transmission when the output pressure is below a predetermined percentage of the transmission line pressure and to direct line pressure to the clutch when the predetermined percentage is exceeded. This permits the clutch to be controlled at or below a slipping engagement state.