Method for determining a kisspoint of a clutch. A method is provided of determining a kisspoint of a clutch in a driveline of a vehicle comprising a. increasing a target clutch pressure of a clutch piston up to a first predetermined test target pressure, b. increasing the target clutch pressure up to an upper target pressure and subsequently keeping the target clutch pressure stable for a predetermined time interval, c. monitoring a parameter indicative for the filling of the clutch piston, e.g. the rotational speed of a pump, during the predetermined time interval, d. repeating steps a., b., and c. for at least one further predetermined test target pressure, and e. determining the kisspoint based on the monitored parameter indicative for the filling of the clutch piston.

The present disclosure describes a hydraulic control system comprising a first pressure chamber and a second pressure chamber, each pressure chamber configured to receive a hydraulic fluid, a first movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the first pressure chamber and a second movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the second pressure chamber, a hydraulic command circuit configured to provide the hydraulic fluid and to control the hydraulic pressure of the hydraulic fluid in the first pressure chamber and/or the second pressure chamber, having a switchable valve in fluid communication with the first pressure chamber, wherein the switchable valve is configured to be pilotable depending on the hydraulic pressure of the hydraulic fluid in the second pressure chamber.

A line pressure control method for a double clutch transmission (DCT) includes estimating a line pressure, which decreases with stoppage of an electric oil pump, based on a linear regression model using state variables of the DCT that are related to a line pressure change, and driving the electric oil pump when the line pressure estimated based on the linear regression model reaches a predetermined lower limit.

The present disclosure describes a hydraulic control system comprising a first pressure chamber and a second pressure chamber, each pressure chamber configured to receive a hydraulic fluid, a first movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the first pressure chamber and a second movable member configured to assume a position depending on a hydraulic pressure of the hydraulic fluid in the second pressure chamber, a hydraulic command circuit configured to provide the hydraulic fluid and to control the hydraulic pressure of the hydraulic fluid in the first pressure chamber and/or the second pressure chamber, having a switchable valve in fluid communication with the first pressure chamber, wherein the switchable valve is configured to be pilotable depending on the hydraulic pressure of the hydraulic fluid in the second pressure chamber.

In a control device for a vehicle including: a dog clutch mechanism that is disposed in a power transmission path in which a driving force is transmitted from an engine to a wheel and is operated by a hydraulic actuator; and an electric oil pump that supplies hydraulic pressure to the hydraulic actuator, rotation of the engine is stopped in a state in which the dog clutch mechanism is engaged by the hydraulic pressure supplied from the electric oil pump at a time during an engine stop operation, the rotation of the engine is started in the state in which the dog clutch mechanism is engaged by the hydraulic pressure supplied from the electric oil pump at a time during an engine restart operation, hence occurrence of up-lock of the dog clutch mechanism is prevented.

A vehicle driveline component having a dual friction clutch differential assembly and a hydraulic circuit for operating the friction clutches. The hydraulic circuit includes a pair of normally open, solenoid operated valves that are selectively closed to control the fluid pressure that acts on the friction clutches. The hydraulic circuit provides a simplified and cost-effective means for providing disconnecting and/or torque vectoring capabilities to the vehicle driveline component.

A power transmitting component can include a friction clutch, a ram, a pump, a fluid storage device and a valve. The ram can have a piston chamber and a piston movable therein between a first and second position to engage the friction clutch. A first inlet/outlet of the pump can be fluidly coupled to a reservoir. The fluid storage device can hold pressurized hydraulic fluid. The valve can be fluidly coupled with the piston chamber, a second inlet/outlet of the pump, and the fluid storage device. When in a first mode, the valve can permit fluid communication between the pump and the fluid storage device, inhibit fluid communication between the piston chamber and the pump, and inhibit fluid communication between the piston chamber and the fluid storage device. When in a second mode, the valve can permit fluid communication between the pump, the fluid storage device, and the piston chamber.

Setting a system pressure for a hydraulically actuated clutch comprises a) Providing a system comprising a pump drivable by an electrically operated motor controlled by a control unit that senses a motor current and rotational speed and a system temperature is determined; b) a characteristic diagram is provided specifying values for at least the motor current and rotational speed for different system operating points; c) Accessing the characteristic diagram while operating a vehicle; d) Sensing at least the motor current and rotational speed at at least a first operating point and determining the system temperature; e) Comparing the values, acquired in step d) for the current and speed with the values for the current and rotational speed from the characteristic diagram according to step b); f) Adapting the characteristic diagram for the system on the basis of the parameters determined in step d).

A clutch cylinder in a hydraulic pressure system can be charged with a controlled rotational speed of a pump to deliver hydraulic fluid into the clutch cylinder until a biting point of the clutch is reached and exceeded and a motor current of the pump has attained a predetermined minimum value. On the basis of a profile of the controlled rotational speed, a first volume of the hydraulic fluid delivered into the clutch cylinder by the pump up is determined until the minimum value is attained. The value of the first volume can be reduced by a predetermined amount to a second volume, which can be used for clutch processes during vehicle operation, wherein the second volume is delivered into the clutch cylinder, with a high rotational speed of the pump, such that the clutch is filled such that the biting point of the clutch is not quite reached.

A hydraulic system includes a normally open-type hydraulic clutch which connects or disconnects a power transmission line between an engine and a wheel, an actuator which supplies a hydraulic pressure to the hydraulic clutch, an oil flow path which connects the actuator to the hydraulic clutch, a valve member which is provided on the oil flow path and which enables to switch between an open state where the oil flow path communicates and a closed state where the oil flow path closes, a hydraulic pressure sensor which is provided on the oil flow path, and a bypass flow path which bypasses the valve member. A one-way valve, which permits a supply of a hydraulic pressure from an actuator side to a hydraulic clutch side and which shuts off a supply of a hydraulic pressure from the hydraulic clutch side to the actuator side, is provided on the bypass flow path.