A control method of a clutch for a vehicle may include determining whether or not learning of clutch characteristics is possible; learning the clutch characteristics when the learning of the clutch characteristics is possible; determining a clutch torque for controlling the clutch in consideration of a change amount in the clutch torque before and after the learning and controlling the clutch by the determined clutch torque; and determining whether or not it is difficult to continue to learn the clutch characteristics.

A control system for a vehicle configured to accurately learn an initial engagement position of a clutch. The control system is applied to a vehicle comprising a clutch that selectively transmits power between a prime mover and drive wheels, and a detector that detects an input speed of the clutch rotated by the prime mover. A controller executes a learning of the initial engagement position of the clutch, if a reaction time until an input speed of the clutch is changed by engaging the clutch gradually while maintaining the input speed of the clutch to a constant speed is shorter than a threshold period of time.

Disclosed is a clutch control reference value setting method including generating a current-hydraulic pressure model, setting a temporary VKP to a current causing a maximum difference between a model hydraulic pressure and a measured hydraulic pressure, determining that the temporary VKP is valid when a deflection amount calculated from a difference integral value acquired by integrating differences between the model hydraulic pressure and the measured hydraulic pressure while increasing the current is greater than a first reference value under a condition that the first target pressure is applied to the clutch, determining that the temporary VKP is appropriate when a deflection amount calculated from a difference integral value acquired by integrating differences between the model hydraulic pressure and the measured hydraulic pressure while increasing the current is proper under a condition that a second target pressure is applied to the clutch.

A clutch device has at least a multiplicity of clutch discs which are in frictional contact with one another, and a control unit which controls the clutch device. The clutch device is calibrated repeatedly during an operating time of the clutch device. A first calibration is performed at a first point in time. A second calibration is performed at a second point following the first calibration. The first point in time and the second point in time are within a first operating time of the clutch device and occur within a first time interval. At least a third calibration is performed in a subsequent second operating time at a third point in time. At least the second calibration is performed within a second interval of the third point in time. The first and second intervals are determined by the control unit based on a mileage of a vehicle or an energy input into the clutch device. The first interval is shorter than the second interval.

A vehicle drive train, has a clutch unit actuatable by an actuating unit, and a sensor for determining the coupling status. The actuating unit includes an electromagnetic actuator having a piston movable from a starting to an end position. At least the piston and the clutch are acted on by a transmission fluid. Operating the drive train can include: a) actuating the actuator and moving the piston from the starting position; b) ascertaining a measured sensor value; c) ascertaining a temperature of the transmission fluid by measuring an electrical resistance of the actuator and/or measuring a first time interval between actuation of the actuator according to step a) and the detection by the sensor of an intermediate position that is reached by the piston; d) determining an actual position of the piston based on the measured sensor value and the temperature; and e) moving the piston, starting from the determined actual position, into the end position.

Systems and methods for operating a vehicle that includes an engine and an electric machine are described. In one example, an actual total number of transmission gear downshifts are counted to determine whether or not a transmission clutch characterization is immature. The transmission clutch characterization may be adjusted if it is determined to be immature.

A method determines the travel of a clutch in a hydraulic clutch-actuation system. A hydraulic signal which extends between a transmitting end and a receiving end is acted upon by an acoustic signal for the generation of a wave packet. The acoustic signal on the transmitting end of the clutch-actuation system is fed into the hydraulic fluid, a wave packet generated by the acoustic signal on the receiving end is reflected back to the transmitting end, a running time of the transmitted and reflected wave packet on the transmitting end is evaluated to determine the coupling travel.

A method for controlling a positive gearshift unit includes, in an engagement procedure, a coupling element, which is connected to a first coupling half and which has a beveled coupling toothing, is brought into engagement with a blocking element, which has a blocking toothing and which is connected to a second coupling half, and is brought into engagement with a catch element, which is connected to the second coupling half, which has a beveled catch toothing, and which is able to move circumferentially with respect to the blocking element. In the engagement procedure, a touch-point is set which comes after a crossing of a synchronous rotational speed in a rotational speed difference profile.

The disclosure relates to a method for calibrating a drive system for an axle of a motor vehicle; wherein the drive system includes at least one electric machine as the drive unit, a drive shaft driven by the drive unit, a first output shaft and a second output shaft, as well as a first clutch connecting the drive shaft to the first output shaft and a second clutch connecting the drive shaft to the second output shaft.

A control system for a vehicle configured to accurately learn an initial engagement position of a clutch. The control system is applied to a vehicle comprising a clutch that selectively transmits power between a prime mover and drive wheels, and a detector that detects an input speed of the clutch rotated by the prime mover. A controller executes a learning of the initial engagement position of the clutch, if a reaction time until an input speed of the clutch is changed by engaging the clutch gradually while maintaining the input speed of the clutch to a constant speed is shorter than a threshold period of time.