Methods and systems are provided for operating a powertrain or driveline of a hybrid vehicle that includes two electric machines and a transmission are described. In one example, vehicle propulsion is maintained while transmission operating parameters are determined for improving transmission operation. In particular, a rear drive unit maintains vehicle speed and monitors torque delivered via an output of the 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.

A method includes determining, via a processor, a speed ratio of a transmission system including a transmission based at least in part on an output speed of the transmission system and an input speed of the transmission system; determining, via the processor, a first torque percentage for a first clutch coupled to the transmission based at least in part on the speed ratio; determining, via the processor, a second torque percentage for a second clutch coupled to the transmission based at least in part on the speed ratio; outputting, via the processor, a signal indicative of a first torque command to a clutch assembly based at least in part on the first torque percentage; and outputting, via the processor, a signal indicative of a second torque command to the clutch assembly based at least in part on the second torque percentage.

A method for operating a vehicle drive-train having a continuously power-branched transmission with secondary coupling. In the open operating condition of reversing clutches of a reversing gear unit, torque applied in the area of a drive output can be supported by a range group in the area of a variator. In the event of a command to interrupt the power flow between a drive engine and the drive output, it is checked whether the vehicle is on an inclined surface and if the result of that inquiry is positive, the power flow between the drive engine and the transmission is interrupted at the latest when the rotational speed of the drive output is reduced to zero by opening the reversing clutches, while the active connection between the drive output and the variator is maintained by way of the range group.

A clutch disengagement position is detectable with high precision even during speed change. A vehicle transmission device can include a transmission including a main shaft to which rotational power from an engine is inputted via a clutch, and a countershaft, a clutch operation member that is driven by an actuator and performs disengaging and engaging operations of the clutch, and a driving wheel to which rotational power of the countershaft is transmitted via a driving force transmitting device. A damper member deformed by a driving force is provided in the countershaft, the driving force transmitting device or the driving wheel, or among the countershaft, the driving force transmitting device and the driving wheel. A control device learns a clutch disengagement operation amount when the control device detects deceleration of a predetermined value of the rotational frequency of the main shaft.

During the inertia phase of a shift, the oncoming clutch is controlled to alleviate shift quality degradation due variability of clutch friction coefficient. The friction coefficient sometimes increases as the slip speed nears zero. The commanded clutch pressure is a sum of an open loop term and a closed loop term. The open loop term decreases as the clutch slip decreases. Thus, when the friction coefficient increases at the end of the inertia phase, the clutch torque remains nearly constant. When the friction coefficient does not increase at the end of the inertia phase, the closed loop term responds to the resulting decreasing rate of slip speed reduction.

A method for controlling a slip of a clutch device of a gearbox of a vehicle includes measuring at least one rotational speed value on a gearbox shaft of the gearbox; determining an active gearbox shaft; determining the angular acceleration on the active gearbox shaft determined, on the basis of the at least one measured rotational speed value; producing a rattling characteristic value on the basis of the angular acceleration determined over at least one time interval; and controlling the slip of the clutch device on the basis of a comparison of the rattling characteristic value produced with at least one rattling threshold value.

A method for operating a drive train for a motor vehicle, with at least one primary drive axle and at least one secondary drive axle, which are operatively connected to each other via a clutch to an adjustable transmission torque. At the same time it is provided that a vibration amplitude of a vibration of the drive train is determined and in a damping operation type of the drive train, the transmission torque is determined from the vibration amplitude and adjusted on the clutch.

To provide a device to facilitate protection of a clutch while minimizing degradation of the torque transmission performance. A hydraulic clutch for drive power distribution is provided between a drive power source and auxiliary driving wheels, and a commanded torque is determined depending on the travel situation. The hydraulic pressure corresponding to the commanded torque is supplied to the hydraulic clutch. The surface temperature of the clutch is estimated (detected). The device generates a limiting value to limit the commanded torque when the difference in rotation between input and output shafts of the clutch is not less than a predetermined threshold and the commanded torque is not less than a predetermined value and performs control so as to increase the limiting value with an increase in the surface temperature of the clutch.

A transmission includes an electro-hydraulic controller that includes redundancy in the hydraulic circuit that permits single fault failures to be compensated for by changing the flow path of hydraulic fluid to bypass the single fault failure. The redundancy results in the ability of the transmission to maintain full operation in all modes.