Abstract: A hydraulic control system for distributing pressurized fluid to a multi-mode hybrid-type power transmission is provided, as well as a method for regulating the same. The hydraulic control system includes an engine-driven main pump in fluid communication with a main regulator valve, and an electrically-driven auxiliary pump in fluid communication with an auxiliary regulator valve. One pressure control solenoid provides feedback (boost) pressure to both regulator valves, and thereby modify output of the main and auxiliary pumps. A controller selectively modifies distribution of boost pressure to ensure a continuous and controllable feed of hydraulic pressure to the transmission during all vehicle operations.

Abstract: A hydraulic control system for a multi-mode hybrid-type power transmission is provided, including an engine-driven main pump in fluid communication with a main regulator valve, and an electrically driven auxiliary pump in fluid communication with an auxiliary regulator valve. A first pressure control solenoid is configured to provide boost pressure to the main regulator valve and thereby boost output of the main pump. A second pressure control solenoid is configured to provide boost pressure to the auxiliary regulator valve and thereby boost output of the auxiliary pump. The distribution of boost pressure from the pressure control solenoids is selectively modified such that at least one of the flows of pressurized fluid from the pumps is equal to the current line pressure requirements of the transmission during engine auto-start and auto-stop, and transitions thereto. An improved method for regulating the hydraulic control system is also provided.

Abstract: A method for controlling a hydraulic flow within a powertrain comprising an electromechanical transmission mechanically-operatively coupled to an engine adapted to selectively transmit power to an output, wherein the transmission utilizes a hydraulic control system serving a number of hydraulic oil consuming functions includes monitoring minimum hydraulic pressure requirements for each of the functions, determining a requested hydraulic pressure based upon the monitoring minimum hydraulic pressure requirements and physical limits of the hydraulic control system including a maximum pressure, determining a desired flow utilizing a hydraulic control system flow model based upon the requested hydraulic pressure, and utilizing the desired flow to control an auxiliary hydraulic pump.

Abstract: The present invention relates to a torsional damper for an electrically-variable transmission. The torsional damper is equipped with a hydraulically actuable lock-out clutch to directly couple the engine to the input shaft of the transmission. The electric motors provided with the electrically-variable transmission can serve to effectively cancel out engine compression pulses when the springs of the torsional damper are locked out. When the engine is off and the torsional damper assembly is in use, an auxiliary pump is provided to pump oil to the torsional damper assembly. The lock-out clutch is hydraulically balanced by the oil supplied by the auxiliary pump. The pump is strategically mounted to the transmission housing in a manner to minimize the distance between the auxiliary pump and the transmission without affecting any vehicle ground clearance requirements.

Abstract: The present invention relates to a torsional damper for an electrically-variable transmission. The torsional damper is equipped with a lock-out clutch to directly couple the engine to the input shaft of the transmission. The electric motors provided with the electrically-variable transmission can serve to effectively cancel out engine compression pulses when the springs of the torsional damper are locked out. The present invention also includes damper springs of variable rates to effectively attenuate distinctive or inconsistent torque fluctuations when the engine is operating in displacement-on-demand mode.

Abstract: The present invention relates to a torsional damper for an electrically variable transmission. The torsional damper is equipped with a hydraulically actuable lock-out clutch to selectively directly couple the engine to the input shaft of the transmission. The electric motors provided with the electrically variable transmission can serve to effectively cancel out engine compression pulses when the springs of the torsional damper are locked out. During higher speeds the centrifugal loading placed on oil in the torsional damper increases, which may cause the lock-out clutch to inappropriately engage. The present invention hydraulically balances the hydraulic actuator (or piston) driving the lock-out clutch to appropriately regulate lock-out clutch engagement.