A vehicle control unit performs filling control in which the vehicle control unit boosts an oil pressure in a second oil passage by supplying electric power to a pressure regulating valve with a switch valve being in a first state in which the switch valve connects a first oil passage to a clutch and disconnects the second oil passage from the clutch, torque replacement control in which the vehicle control unit increases motor torque while reducing shaft torque of an engine, and clutch disengagement control in which the vehicle control unit disengages the clutch while performing hydraulic control by the pressure regulating valve with the switch valve being in the second state in which the switch valve connects the second oil passage to the clutch and disconnects the first oil passage from the clutch.

An arrangement for a multi-clutch assembly including a popoff valve is disclosed. The arrangement also includes a first clutch, a second clutch, and a spool valve assembly. Depending on the mode, the popoff valve either provides a flowpath for residual hydraulic fluid from a latching chamber of the spool valve assembly to a vent of the popoff valve, or provides a flowpath for supplying hydraulic fluid to the latching chamber of the spool valve assembly via a fluid connection from a supply inlet to a latch port of the popoff valve.

A clutching device of an automatic transmission may include a clutch drum connected to a first rotation element, a clutch connected to the clutch drum and a second rotation element, and a piston device to operate the clutch, wherein the piston device may include a first piston forming a first sealed space with the first rotation element and the clutch drum and moving toward the clutch by a hydraulic pressure supplied to the first sealed space, a second piston forming a second sealed space with the first piston and moving toward the clutch to directly press the clutch by a hydraulic pressure supplied to the second sealed space, a spring retainer disposed on the first rotation element and forming a third space with the second piston and the first rotation element, and a return spring stored in the third space and abutted by the spring retainer and the second piston.

The present disclosure provides a hydraulic control system for an automatic transmission. The system includes: a linear solenoid valve configured to control a line pressure and to supply the line pressure to a coupling element, a shift valve to which an output hydraulic pressure of the linear solenoid valve is supplied, and a transmission control unit configured to control the shift vale and the linear solenoid valve.

A method controls a hydraulic system for an actuation device and a cooling and/or lubricating device of a motor vehicle. The hydraulic system has a pump, multiple first actuation valves which are each arranged between a system rail connected to a pump outlet and a hydraulic consumer, as well as an additional valve which is arranged between the pump outlet and a coolant and/or lubricant supply line. The pump is switched between a normal operation and an enhanced operation according to an existing total energy demand of the hydraulic consumer. In normal operation, the pump is permanently driven and the additional valve is opened and closed to control pressure in the system rail. In enhanced operation, the pump is permanently driven, the additional valve is permanently closed and each of the actuation valves is operated according to an individual energy demand of the respective hydraulic consumer.

A hydraulic circuit for a power transmission device has an oil passage supplying hydraulic pressure of hydraulic fluid to the power transmission device mounted on a vehicle and a hydraulic actuator on which the hydraulic pressure of the hydraulic fluid in the oil passage acts, the oil passage is provided with a concave portion of the inner surface of the oil passage that is recessed upward in the state of mounting on the vehicle. The concave portion is located upstream of the hydraulic actuating portion in the oil passage and above the hydraulic actuating portion when the unit is mounted in the vehicle.

A control device of a vehicle power transmission device including a first power transmission path transmitting power by engaging a first clutch, a sub-clutch and a second power transmission path transmitting power by engaging a second clutch each disposed between an engine and drive wheels and parallel to each other, the device including a fail-safe valve for preventing simultaneous engagement of the first and second clutches, the fail-safe valve configured to be switched to a fail-safe spool position preventing simultaneous engagement of the first and second clutches by a hydraulic pressure of a hydraulic fluid supplied to the first clutch or an output pressure of a first electromagnetic valve controlling the hydraulic pressure and the hydraulic pressure of the hydraulic fluid supplied to the second clutch or an output pressure of a second electromagnetic valve controlling the hydraulic pressure, the second electromagnetic valve configured to increase the output pressure.

A driving-force transmitting apparatus includes first and second friction clutches, a piston that presses the first and second friction clutches, a hydraulic pump that feeds hydraulic oil to a cylinder chamber in the piston, an electric motor that drives the hydraulic pump, and a control apparatus that controls the electric motor to adjust the discharge pressure of the hydraulic pump. The control apparatus has a feedback control apparatus that controls the electric motor using a correction value based on a deviation between a target value and an actual value of the discharge pressure of the hydraulic pump, a hydraulic-oil temperature estimating apparatus that estimates a temperature of hydraulic oil, and a gain adjusting apparatus that changes a correction amount for feedback control in accordance with the estimated temperature of the hydraulic oil.

A clutch actuating device has an actuating cylinder with piston and rod-side chamber, a multiplier cylinder with piston-side and rod-side chambers separated by a piston, a rod(s) interconnecting the pistons, and a directional control valve. The valve has a pilot port, ports in fluid connection with piston-side and rod-side chambers of the multiplier cylinder, and a port in fluid connection with a secondary source. When a first fluid pressure (P1) from a first pressure source is applied to the pilot port and rod-side chamber of the actuating cylinder, a second fluid pressure (P2) is applied to the piston-side chamber of the multiplier cylinder by the secondary source. This results in the first and second fluid pressures (P1 and P2) acting on the piston of the actuating cylinder to produce a clutch actuation fluid pressure.

An arrangement for a multi-clutch assembly including a popoff valve is disclosed. The arrangement also includes a first clutch, a second clutch, and a spool valve assembly. Depending on the mode, the popoff valve either provides a flowpath for residual hydraulic fluid from a latching chamber of the spool valve assembly to a vent of the popoff valve, or provides a flowpath for supplying hydraulic fluid to the latching chamber of the spool valve assembly via a fluid connection from a supply inlet to a latch port of the popoff valve.