A drive apparatus for a hybrid vehicle includes: (a) a hybrid drive unit having (a-1) an automatic transmission, (a-2) a first rotating machine and (a-3) an engine connected to the first rotating machine through a hydraulically-operated connecting/disconnecting device; (b) an electric drive unit including a second rotating machine; and (c) a hybrid control device configured, in event of an anomaly that disables a shift control of the automatic transmission, to generate an electric power by causing the first rotating machine to be rotated by the engine and drive the hybrid vehicle to run by causing the second rotating machine of the electric drive unit to be operated with use of the generated electric power, in a state in which a power transmission through the automatic transmission is cut off and the connecting/disconnecting device is engaged.

A hydraulic circuit for a hybrid powertrain having an engine and an electric motor. The hydraulic control circuit includes a first pressure regulating valve configured to cooperate with a shift valve for selectively communicating a hydraulic fluid to a hydraulic piston actuator of a clutch assembly for engaging the engine to a driveline. The hydraulic control circuit further includes a second pressure regulating valve configured to selectively communicate a flow of hydraulic fluid to a cooling circuit for the cooling of the electric motor and to cooperate with a check valve and the shift valve to actuate the hydraulic piston actuator during a predetermined fail mode of the first pressure regulating valve, thus providing a limp-home mode by coupling the torque output from the engine to driveline of the vehicle.

A vehicle includes a transmission shiftable by hydraulic pressure, a main oil passage that delivers operating oil, a first oil passage that delivers the operating oil from the main oil passage to the transmission, a first valve that opens/closes the first oil passage, a controller that controls the first valve, a second oil passage that delivers the operating oil from the main oil passage to the transmission, and a manually drivable second valve that opens/closes a section of the first oil passage that is closer to the main oil passage than the first valve and the second oil passage. The second valve is switchable between the automatic control state in which the first oil passage is opened and the second oil passage is closed and the manual control state in which the first oil passage is closed and the second oil passage is opened.

In a power transmission apparatus for a vehicle, in event of detection of an anomaly with a possibility of an ON failure of a lockup hydraulic control valve, a fail safe mode is established by placing a first switching valve and a third switching valve in respective predetermined connection states, and placing a failure switching valve in a predetermined connection state based on an output of the lockup hydraulic control valve, whereby a lockup clutch is held in its released state, and a forward-driving engagement device is engaged by a control pressure of a second hydraulic control valve, for thereby enabling a forward driving of the vehicle. Upon selection of a neutral range in the event of the detection of the anomaly, an output of the lockup hydraulic control valve and an output of the second hydraulic control valve are stopped.

A hydraulic circuit for a hybrid powertrain having an engine and an electric motor. The hydraulic control circuit includes a first pressure regulating valve configured to cooperate with a shift valve for selectively communicating a hydraulic fluid to a hydraulic piston actuator of a clutch assembly for engaging the engine to a driveline. The hydraulic control circuit further includes a second pressure regulating valve configured to selectively communicate a flow of hydraulic fluid to a cooling circuit for the cooling of the electric motor and to cooperate with a check valve and the shift valve to actuate the hydraulic piston actuator during a predetermined fail mode of the first pressure regulating valve, thus providing a limp-home mode by coupling the torque output from the engine to driveline of the vehicle.

Hydraulic system and method for controlling pressure in a hydraulic system for a vehicle transmission with at least a primary friction element (2) and a secondary friction element (3) for coupling and transmitting engine power to the wheels of the vehicle by actuation of the friction elements (2) via the hydraulic system, comprising; supplying pressurized fluid to a line pressure circuit (7) by means of a pressure pump system having at least two outlet lines (5); providing a bypass circuit (9) on the pressure pump system that, when the bypass circuit (9) is open to allow flow therethrough; providing a bypass operating element (11) for controlling the bypass circuit (9) via a bypass valve (10); wherein the bypass operating element (11) additionally controls the secondary pressure on the secondary friction element (3) via a secondary valve (19); such that in a determined state; the bypass operating element (11) is actuated to open the bypass circuit (9) to reduce the flow to the line pressure circuit (7) and additionally to reduce the pressure on the secondary friction element (3) to a value lower than the pressure on the primary friction element (2), such that less torque is provided.

A drive apparatus of a hybrid vehicle including an internal combustion engine, a first motor-generator, a power division mechanism, a second motor-generator and a mode switching unit. The mode switching unit includes a hydraulic pressure source, a planetary gear mechanism, a clutch actuator, a brake actuator, a parking lock actuator, control valves, a failure detecting part and an electronic control unit, A microprocessor of the electronic control unit is configured to perform controlling the control valves so that hydraulic oil is supplied to the clutch actuator, the brake actuator and the parking lock actuator, respectively, when a parking brake is operated in a state that the failure of the third control valve is detected by the failure detecting part.

A transmission includes an accumulator to hold one of more shift elements in an engaged state while an engine is off. The transmission also includes a hydraulic park system that disengages park in response to engagement of two shift elements. In some circumstance, draining the accumulator in an uncontrolled manner in the presence of a failed valve may lead to unintentionally disengaging park. To avoid this, the accumulator is discharged in a controlled manner. Fluid is first transferred from the accumulator to a shift element apply chamber. Then, the fluid is vented from the shift element apply chamber.

A vehicle includes a transmission shiftable by hydraulic pressure, a main oil passage that delivers operating oil, a first oil passage that delivers the operating oil from the main oil passage to the transmission, a first valve that opens/closes the first oil passage, a controller that controls the first valve, a second oil passage that delivers the operating oil from the main oil passage to the transmission, and a manually drivable second valve that opens/closes a section of the first oil passage that is closer to the main oil passage than the first valve and the second oil passage. The second valve is switchable between the automatic control state in which the first oil passage is opened and the second oil passage is closed and the manual control state in which the first oil passage is closed and the second oil passage is opened.

In the case where an automatic transmission is configured such that the winding diameter of a belt around a primary pulley (41) is larger than the winding diameter of the belt around a secondary pulley (42) when a primary pressure and a secondary pressure are equal to each other, a fail-safe valve (124) varies the position of a first valve element (123p1) of a primary pressure control valve (123P) such that the primary pressure is reduced when a first electromagnetic actuator (SLPs) and a second electromagnetic actuator (SLSs) become inoperable.