A vehicle power transmission device includes a forward first clutch between an engine and an input shaft of a continuously variable transmission, and a second clutch between an output shaft of the continuously variable transmission and driving wheels. When the hydraulic fluid of the hydraulic pump is not supplied to the first disconnection device and the second disconnection device, a dragging torque generated in the second disconnection device is larger than a dragging torque generated in the first disconnection device.

A transmission includes an input shaft coupled to a prime mover, a countershaft, main shaft, and an output shaft, with gears between the countershaft and the main shaft. A shift actuator selectively couples the input shaft to the main shaft by rotatably coupling gears between the countershaft and the main shaft. The shift actuator is mounted on an exterior wall of a housing including the countershaft and the main shaft. An integrated actuator housing is operationally coupled to the shift actuator and a linear clutch actuator. The linear clutch actuator is a self-adjusting actuator, and the transmission includes a self-adjusting clutch.

A control device for a vehicle includes: a coasting control unit configured to, during normal traveling at a low speed within a predetermined range, cause a vehicle to travel through inertia by blocking power transmission between an engine and driving wheels by disengaging a power transmitting/blocking device that includes a first engaging portion connected to the engine and a second engaging portion connected to the driving wheels, and by stopping the engine; and a return control unit configured not to full-engage the power transmitting/blocking device while the engine is cranking by a motor in a case of returning from coasting traveling to normal traveling and to full-engage the power transmitting/blocking device after the motor stops.

To provide a device to facilitate protection of a clutch while minimizing degradation of the torque transmission performance. A hydraulic clutch for drive power distribution is provided between a drive power source and auxiliary driving wheels, and a commanded torque is determined depending on the travel situation. The hydraulic pressure corresponding to the commanded torque is supplied to the hydraulic clutch. The surface temperature of the clutch is estimated (detected). The device generates a limiting value to limit the commanded torque when the difference in rotation between input and output shafts of the clutch is not less than a predetermined threshold and the commanded torque is not less than a predetermined value and performs control so as to increase the limiting value with an increase in the surface temperature of the clutch.

Disclosed is a hydraulic pressure supply system of a dual clutch transmission for a vehicle in which by independently configuring a low pressure supply route and a high pressure supply route, the hydraulic pressure supply system can enable a low hydraulic pressure that is generated in a hydraulic pump for a low pressure to be supplied to a gear lubrication device and a clutch cooling/lubrication device and enable a low hydraulic pressure that is generated in a hydraulic pump for a high pressure to be supplied to a gear control device and a clutch control device.

A dual-clutch transmission includes a hydraulic system for actuating hydraulic cylinders of the clutches and the shifting elements. The hydraulic system has a pressure accumulator providing an accumulated pressure in the hydraulic system, and control valves actuatable by a control unit and respectively arranged in pressure lines routed to the hydraulic cylinders of the clutches to adjust the hydraulic pressure applied to the clutches. Pressure sensors associated with the control unit detect the hydraulic pressure. The control unit activates a pressure reduction mode when detecting a long vehicle downtime, and the accumulated pressure can be reduced in the pressure reduction mode, in which the control unit continuously opens the control valve associated with one clutch. Additionally, the pressure sensor associated with the first clutch together with the control unit is integrated into a control circuit in which the first pressure sensor assumes the detection of the actual accumulated pressure value.

A hydraulic controller for an automatic transmission of a motor vehicle includes at least one gear shift piston-cylinder unit having a gear shift piston for actuating a shifting element in the form of a multi-plate clutch, and a gear shift pressure chamber in which an actuating pressure may be built up by supplying operating fluid. The gear shift piston-cylinder unit has a centrifugal oil chamber that is separated from the gear shift pressure chamber by a gear shift piston. Operating fluid may be supplied to the centrifugal oil chamber via a centrifugal oil line supplied by a first supply line. The hydraulic controller has a second supply line for supplying operating fluid to the centrifugal oil line. The second supply line may be closed and opened by a centrifugal oil valve.

A hydraulic circuit includes a clutch actuator operatively with a clutch that may be disposed in a transmission. A hydraulic fluid source supplies pressurized hydraulic fluid for the clutch actuator. An on-off valve is disposed in fluid communication between the clutch actuator and the hydraulic fluid source; the on-off valve configured to fill the clutch actuator with hydraulic fluid. An accumulator is disposed in parallel with the on-off valve and in fluid communication with the clutch actuator. The accumulator is adapted to receive hydraulic fluid redirected from the clutch actuator and to provide a counter-pressure for modulating the clutch actuator.

A method for detecting a safe state of a switchable valve of a hydraulic system of an actuator in a motor vehicle includes the at least one first switchable valve, which is actuated by being energized, a pump, and a controller which controls at least the first switchable valve and the pump. The pump delivers the fluid to a first load in a first rotational direction and to at least one second load in a second rotational direction.

A method for detecting a safe state of a switchable valve of a hydraulic system of an actuator in a motor vehicle includes the at least one first switchable valve, which is actuated by being energized, a pump, and a controller which controls at least the first switchable valve and the pump. The pump delivers the fluid to a first load in a first rotational direction and to at least one second load in a second rotational direction.