A clutch control device is provided for a four-wheel drive vehicle for transmitting drive force to the rear wheels. The clutch control device includes a dog clutch and a friction clutch, and a controller that controls the engagement and disengagement of the dog clutch and the friction clutch. In this clutch control device, when there is a request to engage the dog clutch from a disengaged state, the controller, during the engagement control of the friction clutch, first controls the engagement of the friction clutch, monitors the change gradient of the clutch rotational speed difference of the dog clutch and starts engagement of the dog clutch upon determining that the gradient of the clutch rotational speed difference is no longer decreasing.

The present disclosure provides a clutch control method of a hybrid vehicle of the including an entering condition determining step in which a controller determines whether shifting is being performed during regenerative braking; an error calculating step in which the controller calculates a torque error by subtracting observer torque, which is clutch transfer torque calculated by a clutch torque estimator receiving transmission input torque and motor speed, from map torque, which is clutch transfer torque calculated based on a clutch transfer torque map for clutch actuator strokes learned in advance, when shifting is being performed during regenerative braking; a correcting step in which the controller corrects the clutch transfer torque map for the clutch actuator strokes using the torque error calculated in the error calculating step; and a clutch control step in which the controller controls a clutch using the map corrected in the correcting step.

A method of controlling an automatic transmission is provided. The automatic transmission includes a piston having first and second surfaces opposite from each other, friction plates, engaging and disengaging hydraulic pressure chambers for supplying and discharging hydraulic pressure and directing the piston to push the friction plates to be engaged and disengaged, a hydraulic pressure control valve for supplying and discharging hydraulic pressure to and from the chambers, first and second oil paths communicating the valve with the chambers, and a pressure reducing valve disposed in the second oil path and for preventing hydraulic pressure of the disengaging hydraulic pressure chamber from exceeding a given set pressure. The second surface has a larger area for receiving hydraulic pressure than an area of the first surface for receiving hydraulic pressure. The method includes changing the given set pressure according to information regarding a state of the automatic transmission.

A method of selectively controlling a power take-off (PTO) assembly includes positioning a clutch assembly radially between a shaft and a PTO gear, operably controlling the clutch assembly with a controller, and selectively engaging the clutch assembly with the controller. The controller monitors signals received from a plurality of sensors and compares the monitored signals with respective signal thresholds. The clutch assembly is engaged when the compared monitored signals are within the signal thresholds.

In a method for controlling a clutch actuator for an automated manual transmission, when a driver's operation signal is input for operation of the clutch actuator, the hydraulic pressure of a hydraulic chamber of the clutch actuator forms pressure equilibrium with the atmospheric pressure through a pressure equilibrium control by standing by at a control-standby state before an actual stroke position of the clutch actuator enters a hydraulic pressure generation range from a hydraulic pressure release range. When the actual stroke position of the clutch actuator enters the hydraulic pressure generation range from the hydraulic pressure release range, the clutch actuator is moved to the predetermined stroke position by a predetermined operation speed, and then controlled to follow the driver's operation signal.

Systems and methods for selecting and scheduling which of a plurality of engine starting devices starts an internal combustion engine of a hybrid vehicle are presented. In one example, a scheduled start of the internal combustion engine via a driveline disconnect clutch is withdrawn during conditions when both a transmission gear shift is requested or in process and when a driver urgency level is greater than a threshold level.

A clutch control method is used in a vehicle that has a dog clutch and an engagement sensor, which detects an engagement of a dog clutch. The clutch control method includes executing an engagement of the dog clutch when a magnitude of a differential rotation of the dog clutch is less than or equal to a prescribed value when the engagement sensor is normal and then determining the engagement of the dog clutch using the engagement sensor. The clutch control method further includes setting the differential rotation of the dog clutch to a value larger than the prescribed value when the engagement sensor has failed and then determining the engagement of the dog clutch based on a difference between the differential rotation of the dog clutch at a time of starting the engagement of the dog clutch and the differential rotation of the dog clutch.

A gear-position learning device for an automatic clutch transmission includes a transmission configured to be shifted by an operation of a driver of a vehicle, a clutch device disposed in a transmission path between the transmission and an engine and configured to be connected and disconnected by actuation of a clutch actuator, a controller configured to control connection and disconnection of the clutch device performed by the clutch actuator, a shift drum configured to rotate according to a shift operation that the driver performs on a shift operator and switch the shift stage of the transmission, and a rotational position defining mechanism configured to define a rotational position of the shift drum, wherein the controller has a learning mode for learning a rotation angle of the shift drum and is configured to control connection and disconnection of the clutch device during the learning mode such that the shift drum is at a rotational position determined by the rotational position defining mechanism.

A damping arrangement for dampening rotational irregularities in a drive train of a motor vehicle, having a slip arrangement providing slip between an input and output region of a torque-transmitting arrangement. The slip arrangement has a closed-loop control device that performs closed-loop control of the slip dependent on a measured signal for a rotational irregularity. The closed-loop control device performs closed-loop control of the slip dependent on at least one characteristic variable of a periodic oscillation component of an alternating component of a rotational speed proceeding from an average rotational speed. A sensor device is connected to the closed-loop control device and is designed to ascertain the average rotational speed in the torque-transmitting path downstream of the slip arrangement and to ascertain a frequency of the alternating component in the torque-transmitting path upstream of the slip arrangement.

A rotational system can include a shaft assembly rotationally coupling a first rotor, a second rotor, and a fluid pump. A fluid circuit can include the fluid pump that can be configured to motivate a working fluid through the fluid circuit. A pressurizing valve can be disposed downstream of the fluid pump wherein the rotational system can be configured to rotationally decouple the first rotor from the second rotor by closing the pressurizing valve. The pressurizing valve can be actuated by a controller. A method can include raising a pressure differential across a fluid pump driven by a shaft assembly thereby applying an increased braking torque to the shaft assembly. The pressure differential can be raised by actuating a valve in hydraulic communication with the fluid pump. The shaft assembly can rotationally couple a first rotor with a second rotor, and increasing the braking torque can decouple the rotors.