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.

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.

A method ascertains a characteristic variable of a clutch installed in a drive train of a vehicle for transmitting a transmission torque between a clutch input and a clutch output. A first electric motor is connected to the clutch input and to an internal combustion engine and can assume generator operation, during which it is driven by the internal combustion engine. A second electric motor is connected to the clutch output. The clutch input can have a first rotational speed and the clutch output can have a second rotational speed. The transmission torque during generator operation is ascertained by activating the clutch to adopt a slipping state and in doing so by setting a predefined rotational speed difference between the first and second rotational speed. The clutch input torque present at the clutch input is then ascertained and the transmission torque is determined depending on the clutch input torque.

An in-vehicle control apparatus is configured to execute a collision degree calculation process of, when it is determined that gear rattle occurs, calculating a collision degree that indicates a magnitude of a collision between a sleeve chamfer and a gear chamfer based on a rotation speed difference between a sleeve and an idler gear, execute an index value calculation process of calculating an index value that correlates with wear and tear of the sleeve chamfer and the gear chamfer based on the collision degree that is calculated each time it is determined that gear rattle occurs, and execute a wear and tear degree calculation process of calculating a degree of wear and tear of the sleeve chamfer and the gear chamfer by integrating the index value that is calculated each time it is determined that gear rattle occurs.

A dog clutch engagement method of an electric four-wheel drive vehicle includes steps of: when dog clutch engagement is requested during driving, determining a target synchronization speed of the input gear to be a sum of an estimated speed and an offset speed of the output gear; operating a drive unit so that an input gear follows the target synchronization speed; when an actual speed of the input gear reaches the target synchronization speed, moving a sleeve to a meeting position at which the sleeve is in contact with the input gear; and when the actual speed of the input gear is synchronized with an actual speed of the output gear, transporting the sleeve to an engagement position at which the input gear and the output gear are coupled.

A method for controlling a clutch unit for a drive train of a motor vehicle, wherein the clutch unit comprises a wet-running friction clutch for controllably transmitting torque from an input element to an output element of the clutch unit, wherein the clutch unit comprises oil for cooling the friction clutch, wherein heat inputs which contribute to heating the oil of the clutch unit are calculated, heat outflows which contribute to cooling the oil of the clutch unit are calculated and, as a function of the heat inputs and heat outflows, a maximum admissible clutch torque is calculated, and wherein the current clutch torque of the friction clutch is limited to the maximum admissible clutch torque.