Abstract: A hydraulic clutch assembly for a motor vehicle driveline is provided. The clutch assembly comprises an input member, and output member and a friction clutch pack operably disposed therebetween for controlling torque transfer. A first fluid circuit contains hydraulic based fluid at a first pressure and is in fluid communication with the friction clutch pack for lubrication thereof. A second fluid circuit is in fluid communication with the first fluid circuit for replenishing the second fluid circuit with the hydraulic based fluid at a second pressure that is less than the first pressure. The clutch assembly further comprises a motor and a gear train. A first piston is in fluid communication with the second fluid circuit for delivering the hydraulic based fluid thereto A second piston is translated by the hydraulic based fluid displaced by the first piston to actuate the friction clutch pack.

Abstract: In at least one embodiment, a hydraulic clutch assembly for a motor vehicle driveline is provided. The clutch assembly comprises an input member, and output member and a friction clutch pack operably disposed therebetween for controlling torque transfer. A first fluid circuit contains hydraulic based fluid at a first pressure and is in fluid communication with the friction clutch pack for lubrication thereof. A second fluid circuit is in fluid communication with the first fluid circuit for replenishing the second fluid circuit with the hydraulic based fluid at a second pressure that is less than the first pressure. The clutch assembly further comprises a motor and a gear train. The gear train has an input force driven by the motor and an output force. A first piston is in fluid communication with the second fluid circuit for delivering the hydraulic based fluid thereto and is operatively driven by the output force to displace the hydraulic based fluid.

Abstract: An electrohydraulic clutch includes a bidirectional electric motor, a hydraulic circuit and a multiple plate friction clutch pack. The bidirectional electric motor drives a ball screw through a gear reduction assembly. An electric brake on the motor output may be energized to inhibit its rotation. Alternatively, an anti-back drive wrap-spring assembly may be utilized on the motor output. The ball screw output bi-directionally translates a master piston of the hydraulic circuit which in turn advances and retracts an annular slave piston disposed adjacent the friction clutch pack. Hence, actuation of the electric motor displaces hydraulic fluid and compresses or relaxes the friction clutch pack, thereby transferring or inhibiting torque.

Abstract: In a neutral to drive shift timing control mechanism, a flow control arrangement is utilized in an electro-hydraulic control system for controlling a clutch fill period of a neutral to drive shift sequence. The hydraulic control system provides a pressure pulse of predetermined time which opens a valve to permit fluid flow to bypass an accumulator feed orifice to pressurize the clutch apply cylinder and piston to a value substantially equal to the piston return spring force without providing excess flow to the accumulator. The clutch apply pressure is then permitted to increase at a more normal rate which is controlled by the accumulator. The engagement time is determined so that the pulse time can be adjusted if the neutral to drive shift is not within a predetermined time range.

Abstract: An improved control method for properly coordinating a double transition upshift. The state changes of the various clutches of the transmission are sequenced in relation to a dynamic measure of the transmission speed ratio so as to provide consistent high quality shifting. Closed-loop pressure controls are employed in conjunction with the sequencing to ensure timely shift completion.

Abstract: An improved control method for properly coordinating a double transition downshift. The state changes of the various clutches of the transmission are sequenced in relation to a dynamic measure of the transmission speed ratio so as to provide consistent high quality shifting. Adaptive pressure controls are employed in conjunction with the sequencing to compensate for variability.

Abstract: The torque capacity of a torque converter clutch is controlled with a two-state directional valve and a single solenoid operated pressure control valve. In operation, the directional valve is spring biased to a release state in which converter feed pressure is directed to a passage between the clutch plate and the converter input shell to release the clutch and feed the converter. The return fluid from the opposite (apply side) of the clutch is routed through the directional valve to a low pressure fluid cooler. A control pressure generated by the solenoid operated valve develops a hydraulic bias which opposes the spring bias. When the hydraulic bias is sufficiently great, the directional valve shifts to a control state in which the solenoid operated valve controls the pressure supplied to either the apply or release side of the clutch to control its torque capacity.