At the time when a hydraulic actuator is operated to engage a dog clutch, after it is detected that a hydraulic pressure for operating the hydraulic actuator is higher than or equal to a predetermined hydraulic pressure, it is determined whether the dog clutch is not engaged. Therefore, non-engagement determination due to insufficient hydraulic pressure for operating the hydraulic actuator is prevented. Thus, at the time when the hydraulic actuator is operated to engage the dog clutch, it is possible to prevent consumption of time to engage the dog clutch due to unnecessary re-engagement operation.

A first engagement member includes a first meshing portion and rotates integrally with a first shaft. A second engagement member includes a second meshing portion configured to mesh with the first meshing portion and rotates integrally with a second shaft. An electric clutch device drives the first engagement member via a pressing member that extends and contracts in response to drive of a clutch actuator. When the electric clutch device is to be engaged, the first shaft command computation unit sets the first shaft rotation speed command value to be smaller than the rotation speed of the second shaft. Further, after the rotation speed of the first shaft matches the first shaft rotation speed command value, the first shaft command computation unit sets the first shaft rotation speed command value to be gradually closer to the rotation speed of the second shaft.

A method and system are provided for operating a lockup clutch of a torque converter of a motor vehicle. The torque converter includes a pump rotatably driven by a drive unit, a rotatable turbine fluidly coupled to the pump and configured to drive an input shaft of a transmission, and a lockup clutch selectively engageable to non-fluidically couple the pump to the turbine to transmit torque from the drive unit to the transmission. The operation of the lockup clutch is controlled by the system in response to detecting that the motor vehicle is coasting.

A method ascertains a characteristic variable of a clutch installed into the powertrain of a vehicle for transmitting torque between a clutch input and a clutch output. A first electric motor is connected to the clutch input to introduce a first drive torque into the clutch. The torque is ascertained when the vehicle is at a standstill in that the clutch is first opened; the first electric motor is regulated at a first rotational speed; the clutch output is regulated at a second rotational speed; a counter torque which counteracts the transmission torque is applied to the clutch output; the clutch is then closed in order to assume a slipping state in which a specific differential rotational speed between the clutch input and the clutch output is present; the first drive torque is then ascertained; and the transmission torque is determined on the basis of the first drive torque.

This clutch control device includes an engine (13), a transmission (21), a clutch device (26) configured to connect and disconnect motive power transmission between the engine (13) and the transmission (21), a clutch actuator (50) configured to drive the clutch device (26) and change a clutch capacity, a clutch operating element (4b) configured to enable the clutch device (26) to be manually operated, and a control unit (60) configured to calculate a target value (Pt) of a control parameter (Ps) of the clutch capacity in accordance with an amount of operation on the clutch operating element (4b). When the clutch device (26) is operated on a connection side according to an operation on the clutch operating element (4b), the control unit (60) is configured to set the target value (Pt) to a quick connection target value (Pmax) obtained by making a change to the connection side of the clutch device (26) with respect to an operation correspondence target value (Pv) according to the amount of operation on the clutch operating element (4b) if a speed of the operation on the clutch operating element (4b) is higher than or equal to a predetermined specified speed (Sp1).

In a transmission with a lockup clutch, in a case where zero-slip control of the lockup clutch is not established (converged) within a predetermined time, a sweep increase of a lockup clutch hydraulic pressure starts at an increase rate smaller than a normal increase rate in a case where the zero-slip control is established within the predetermined time, the increase rate until the end of the sweep increase is set to be equal to or less than the normal increase rate, and in addition, a hydraulic pressure at the time of the end of the sweep increase is set to be equal to or greater than a hydraulic pressure in a case where the zero-slip control is established within the predetermined time. With such control, in a case where the zero-slip state is not brought, suppressing the occurrence of shock when complete engagement is carried out.

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 includes a single external power access for the shift actuator. A controller interprets controls the shift actuator with actuating and opposing pulses, and interprets a shaft displacement angle, determines if the transmission is in an imminent zero or zero torque region, and performs a transmission operation in response to the transmission in the imminent zero or zero torque region.

A method to control a road vehicle provided with a clutch, which connects an internal combustion engine to drive wheels and is arranged upstream of a servo-assisted transmission; the control method comprises the steps of: checking whether the tyres of the drive wheels are close to a grip limit; and opening the clutch so that the clutch transmits a torque to the drive wheels with a slip of the clutch that is constant and other than zero when the tyres of the drive wheels are close to the grip limit.

A system is configured to control a clutch that connects a first rotating body and a second rotating body. The system includes a biasing portion, an actuator, an energization device, and a control unit. The biasing portion permanently biases the clutch in a connecting direction. The actuator drives the clutch in a disconnecting direction. The energization device energizes the actuator. The control unit controls the energization device. The energization device outputs a first current value to the actuator when a connection of the clutch is detected even if a condition for permitting a disconnection is satisfied. The energization device outputs a second current value lower than the first current value when the condition for permitting the disconnection is satisfied and a disconnection of the clutch is detected.

A control method for a work vehicle, includes: acquiring a signal for changing a state of a traveling device, to which power is transmitted via a transmission and a clutch, between forward, neutral, and reverse states; outputting a command for reducing a torque of an output shaft connected to the traveling device in a state where a first clutch is engaged, before a specified time elapses from a time point at which the signal for changing to the neutral state is acquired in a state where the first clutch is engaged; outputting a command for releasing the first clutch after the specified time elapses; and outputting a command for controlling the transmission so that a rotation speed of an input-side element of a second clutch to be engaged next coincides with that of an output-side element of the second clutch in a state where the first clutch is released.