One solenoid valve included in a hydraulic pressure control device has at least two functions among the following (1) to (6) functions, (1) switching a state of a two-way clutch, (2) switching a state of a parking lock mechanism, (3) switching the supply of hydraulic pressure to a first brake that is put into an engaged state when a gear stage selected when driving of a vehicle starts is set, (4) controlling a line pressure adjustment valve so that a decrease in a line pressure is prevented when the temperature of a hydraulic fluid is a first predetermined temperature or higher, (5) preventing the occurrence of a creep phenomenon in a neutral range when the temperature of the hydraulic fluid is a second predetermined temperature or lower, and (6) boosting a line pressure by performing switching to another linear solenoid valve when the line pressure adjustment valve has failed.

A system for determining a torque converter clutch is stuck in an engaged position includes a control module, an engine speed sensor, and a transmission speed sensor. The control module evaluates the torque converter clutch by determining a value of a torque converter clutch command. The torque converter clutch command indicates a position of the torque converter clutch. In response to determining that the value of the torque converter clutch command indicates the disengaged position, the control module calculates accumulated slip based on the transmission speed and the engine speed during an evaluation time. In response to determining the evaluation time is complete, the control module compares the accumulated slip with a calibrated threshold of slip. In response to the accumulated slip being less than or equal to the calibrated threshold of slip, the control module determines the torque converter clutch is stuck in the engaged position.

A change-gear transmission system includes a transmission that can be switched between multiple gears, a gearshift lever for selecting between the gears of the transmission, an automatically actuatable clutch, which is arranged in a drive train in series with the transmission and a control unit for automatically opening the clutch while maintaining a gear engaged in the transmission when a condition for the transition into coasting or gliding mode is fulfilled. The control unit is configured to detect a touch of the gearshift lever by the driver, to open the clutch only when no touch of the gearshift lever is detected, and further in the case that in the coasting or gliding mode, a touch of the gearshift lever is detected, to close the clutch while maintaining the engaged gear.

A transmission includes a selectable one-way clutch with an active state and a passive state. To avoid occupant discomfort and hardware damage, transitions from the passive state to the active state must only be commanded when no or very little slip is present across the selectable one-way clutch. Several methods are presented to eliminate slip, depending on vehicle speed. When the vehicle is stationary, full engagement of a clutch that causes slip to be proportional to vehicle speed eliminates slip. When the vehicle is moving backwards, partial engagement of the above clutch eliminates slip. When the vehicle is moving forwards, full engagement of all but one clutch of a tie-up condition and partial engagement of the remaining clutch of the tie-up condition brings the vehicle to a stop and eliminates slip.

A clutch control method is provided for a four-wheel-drive vehicle in which the main drive wheels are connected to a drive source, and the auxiliary drive wheels are connected via a friction clutch to the drive source. When the vehicle starts off due to an accelerator depressing operation, the friction clutch is engaged to distribute, a drive torque from the drive source to the main drive wheels and the auxiliary drive wheels. In this clutch control method, when the vehicle switches from a traveling state to a stopped state while maintaining in a travel shift position, a control is preformed to apply initial torque as an engagement torque control of the friction clutch while the vehicle is stopped. A magnitude of the initial torque is set to a magnitude that maintains a drive-system torsion state by transmitting torque to an auxiliary-drive-wheel drive system before the vehicle is stopped.

The present invention relates to a saddle-ride type vehicle comprising a clutch assembly (4), interposed between an engine (2) and a gearbox (3), which includes a clutch device (11) in turn comprising two clutch elements (one integral with the shaft of the engine and the other with the input shaft of the gearbox) and return means (12) that keep these elements (11A, 11B) in contact in a closure condition of the clutch. According to the invention, the clutch assembly (4) further comprises an operating device (21) of the clutch device that causes detachment of the elements (11A, 11B) of the clutch device up to an opening condition of the clutch assembly. This latter further comprises a control device (6) to limit the torque peaks during gear change. This device comprises an actuation means (5) that, during gear change, exerts a predetermined force (S) in contrast to the force exerted by said return means (12) of the clutch assembly, wherein said predetermined force (S) is less than the force (F) generated by the return means (12) so as to cause a mutual slip of the elements (11A, 11B) of the clutch device (11) without said opening condition being reached. The operating device (21) is of hydraulic type and comprises a primary pump (22) operated by means of a control lever (23), wherein this primary pump (22) is hydraulically connected, through a primary hydraulic circuit (16), to a primary piston (24) acting on at least one of the elements (11A, 11B) of the clutch device (11) in opposition to the return means (12) so that, following an action on the control lever (23), the primary piston (24) exerts an action the elements (11A, 11B) determining the opening condition. According to the invention, the control device (6) comprises a secondary piston (25) connected to the primary piston (24), wherein the actuation means (5) exerts, directly or indirectly, the predetermined force (S) on the secondary piston (25), said predetermined force (S) being transferred to the primary piston (24) in opposition to the force (F) of the return means (12).

A vehicle control device includes control means for executing coasting control, in which a friction engaging element is disengaged and a rotation speed of a rotary shaft of a drive source is set at zero, when a shift range corresponds to a travel range and a coasting condition is established, and the control means executes the coasting control when the shift range is modified to a neutral range.

A control system for a vehicle having an electric motor for providing drive torque to at least one wheel of the vehicle, an internal combustion engine for providing drive torque to at least one wheel of the vehicle, a manual transmission unit having a user selectable gear ratio that includes at least one user selectable forward gear and/or reverse gear, and a clutch actuator, the control system comprising a controller arranged to have three user selectable modes of operation, wherein in a first mode of operation the controller is arranged to allow the clutch actuator to engage and disengage the internal combustion engine from the manual transmission unit based upon a user selection, wherein when the clutch actuator is arranged to engage the internal combustion engine with the manual transmission unit, torque generated by the internal combustion engine is applied to the at least one wheel, and the electric motor is arranged to provide drive torque to the at least one wheel of the vehicle based on whether the user has selected the at least one forward gear or the at least one reverse gear; and in a second mode of operation the controller is arranged to allow the clutch actuator to engage and disengage the internal combustion engine from the manual transmission unit based upon a user selection, and to prevent the electric motor from providing drive torque to the at least one wheel of the vehicle; and in a third mode of operation the controller is arranged to allow the electric motor to provide drive torque to the at least one wheel of the vehicle based on whether the user has selected the at least one forward gear or the at least one reverse gear and to configure the clutch actuator to disengage the internal combustion engine from the manual transmission unit.

A system for determining a torque converter clutch is stuck in an engaged position includes a control module, an engine speed sensor, and a transmission speed sensor. The control module evaluates the torque converter clutch by determining a value of a torque converter clutch command. The torque converter clutch command indicates a position of the torque converter clutch. In response to determining that the value of the torque converter clutch command indicates the disengaged position, the control module calculates accumulated slip based on the transmission speed and the engine speed during an evaluation time. In response to determining the evaluation time is complete, the control module compares the accumulated slip with a calibrated threshold of slip. In response to the accumulated slip being less than or equal to the calibrated threshold of slip, the control module determines the torque converter clutch is stuck in the engaged position.

A clutch control device includes an engine, a gearbox, a clutch device configured to disconnect and connect power transmission between the engine and the gearbox, a clutch actuator configured to drive the clutch device and vary a clutch capacity, and an ECU configured to calculate a control target value of the clutch capacity, and the ECU determines whether an engine rotational number after downshifting by the gearbox enters a high rotation region and decreases the clutch capacity after downshifting when it is determined that the engine rotational number after downshifting enters the high rotation region.