Methods and systems are provided for controlling and diagnosing one or more clutches in a transmission. In one example, a method for operation of a vehicle system is provided that includes at a diagnostic controller or processing unit independent from a driveline controller or processing unit, respectively, determining an engagement state of a clutch in a transmission of the vehicle system, wherein the engagement state is selected from a group of three or more clutch engagement states. The method further includes identifying an unauthorized clutch state based on the engagement state of the clutch and a speed of the vehicle and responsive to the identification of the unauthorized clutch state, operating the vehicle system in a fault state.

Methods and systems are provided for sensing a clutch position. In one example, a method may include generating a single output signal by combining at least an output of a first sensor and an output of a second sensor output, the first sensor and second sensor connected in parallel, and the first sensor and the second sensor sensing a common moving element of a clutch. In one example, the method may further include a first sensor output and a second sensor output provided on a common sensor bus. As another example, the first sensor output may be a master pulse width modulation output, and the second sensor output follows a modulation frequency of the first sensor output.

A method for determining an engagement point (X) of a clutch (3). The clutch (3) has first and second clutch sides (3a, 3b), which are rotationally decoupled when the clutch (3) is disengaged/open and which are rotationally coupled when the clutch (3) is engaged/closed. The method includes the steps of disengaging the clutch (3) and then engaging the clutch (3), in order to determine the engagement point (X). During this, the first clutch side (3a) is driven in rotation and the second clutch side (3b) is accelerated, for at least part of the time, by an acceleration device (4). A control device actuates the clutch (3) in order determine the engagement point (X) of the clutch (3), and a computer program product with stored commands, brings about the sequence of the method when the program is operated on a suitable control unit.

A method sets a predefined position of a clutch actuator comprising a friction spring element. An activation path of the clutch actuator that actuates the clutch is predefined by a coupling torque via a coupling characteristic curve, wherein the predefined position (zo, zu) to be assumed by the clutch actuator is set by a closed-loop controller. To enable the predefined position of the clutch actuator to be set precisely without using additional energy, the predefined position (zo, zu) is corrected by a turning back value (ro, ru) of the friction spring element and the corrected position (zo+ro; zu−ru) of the clutch actuator is approached by the closed-loop controller. After reaching the corrected position (zo+ro; zu−ru) the closed-loop controller is switched off by dissipating the potential energy stored in the friction spring element.

A position detection device includes a magnetic detection element that is positioned radially outside a first clutch component portion and a second clutch component portion of a dog clutch around an axis. The magnetic detection element is provided between a first magnetic flux path portion and a second magnetic flux path portion. The magnetic detection element outputs a sensor signal indicating the direction of a magnetic flux passing between the first magnetic flux path portion and the second magnetic flux path portion. The magnetic detection element outputs a sensor signal indicating a position relationship between the first clutch component portion concerning a first hole portion as well as a first tooth portion and the second clutch component portion concerning the second hole portion as well as the second tooth portion, based on changes in magnetic flux directions depending on the position relationship in a rotation direction around the axis.

A method sets a predefined position of a clutch actuator comprising a friction spring element. An activation path of the clutch actuator that actuates the clutch is predefined by a coupling torque via a coupling characteristic curve, wherein the predefined position (zo, zu) to be assumed by the clutch actuator is set by a closed-loop controller. To enable the predefined position of the clutch actuator to be set precisely without using additional energy, the predefined position (zo, zu) is corrected by a turning back value (ro, ru) of the friction spring element and the corrected position (zo+ro; zu−ru) of the clutch actuator is approached by the closed-loop controller. After reaching the corrected position (zo+ro; zu−ru) the closed-loop controller is switched off by dissipating the potential energy stored in the friction spring element.

Methods and systems for a differential assembly are provided herein. In one example, a diagnostic method includes generating a clutch fault according to a variance between an initial engagement position and a lock point position of a clutch motor that occur during engagement of an interaxle differential (IAD) locking clutch coupled to the clutch motor. In the IAD system, an actuation assembly is coupled to the clutch motor and the IAD locking clutch.

A method for adjusting a clutch characteristic curve, including obtaining a torque-stroke learning value for adjusting the clutch characteristic curve, calculating a convergence value for each control point of the clutch characteristic curve, calculating a difference value between the convergence value and a characteristic curve value for each control point, and determining a new characteristic curve value of each control point according to whether a maximum value of the calculated difference values exceeds a preset reference value.

A method for operating an actuator arrangement for a clutch operating system includes providing an actuator arrangement with a transmission, a piston, and an inductive sensor device. The transmission has an electric motor and a metal lead screw that converts a rotary motion into a linear motion. The piston is connected to the metal lead screw. The method also includes energizing the electric motor to linearly displace the metal lead screw in an axial direction, axially displacing the piston with the metal lead screw, using the metal lead screw as a target for the inductive sensor device, and using the inductive sensor device to determine an axial distance traveled by the piston.

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.