Zf Friedrichshafen Ag

Christian Pannek

Martina Jehle

Daniel Zerlaut

Andreas Schmidt

Angelique Schwimmer

A method for determining reference values of a sensor corresponding to a disengaged operating condition or to an engaged operating condition of a hydraulically actuatable, form-locking shift element (A, F), where at least one operating parameter of the form-locking shift element (A, F) is detected with the sensor during a disengagement and during an engagement of the form-locking shift element (A, F). The method may include subdividing an operating range of the shift form-locking element (A, F) into temperature and pressure classes. The method may further include determining a deviation between a current reference value for a temperature and pressure class of the temperature and pressure classes and an adapted reference value previously determined for the temperature and pressure class. Additionally, the method may include increasing or decreasing the adapted reference value by a predefined increment based on the deviation.

Method for determining reference values of a sensor

A method for determining reference values of a sensor is provided. The reference values correspond to a disengaged operating condition or to an engaged operating condition of a form-locking shift element (A, F). With the aid of the sensor, at least one operating parameter of the shift element (A, F) determinable during a disengagement and during an engagement of the shift element (A, F). A torque, an actuation force of the shift element (A, F), and a differential speed between shift-element halves of the shift element (A, F) are varied during the determination of the reference values of the sensor in such that the form-locking shift element (A, F) is transferred into the disengaged operating condition or into the engaged operating condition.

Method and control apparatus for determining reference values of a sensor

A method for operating a transmission () that includes at least one form-locking shift element (A, F) with two shift-element halves is provided. The shift element (A, F) is disengaged in a first end position and is engaged in a second end position of a displaceable shift-element half. Upon detection of a sensor malfunction, a check is carried out to determine whether the shift-element half, before the malfunction of the sensor, was in an end position as demanded and was actuated by an actuation force acting in the direction of this end position. Power flow in the transmission () is maintained for as long as it takes for the shift-element half, starting from the current end position, to be actuated in the direction of the other end position and/or for the actuation force acting in the direction of the current end position to be less than a threshold value.

Method and control unit for operating a transmission comprising at least one form-locking shift element

A method for monitoring a signal of a sensor is provided. With the aid of the sensor, a current actuating-travel position of at least one movable shift-element half of a form-locking shift element (A, F) of a transmission () is detected during a disengagement or an engagement of the shift element (A, F). A malfunction of the sensor is detected when the current actuating-travel position of the movable shift-element half is located outside the actuating-travel range defined by the end positions and is spaced apart from the first end position or from the second end position by an extent greater than a threshold value. Additionally, it is determined, during a subsequent actuation of the shift element (A, F), depending on rotational speeds of components of the transmission (), whether the movable shift-element half is located in a demanded end position.

Method and control unit for monitoring a signal of a sensor

A method for operating a transmission () is provided, which includes a hydraulic pump drivable on a transmission-input end and at least one form-locking shift element (A, F). One of the shift-element halves is displaceable between a first end position and a second end position with a hydraulic pressure of the hydraulic pump. The current position of the shift-element half is detected with a sensor and is stored as a specified end-position value if the shift-element half is located in one of the end positions, the hydraulic pump is driven, and the shift-element half is actuated, with the hydraulic pressure, towards the current end position. When the hydraulic pressure is less than a threshold value, a deviation is determined between the current position of the shift-element half and the specified end-position value. The hydraulic pressure is increased when the deviation is greater than a threshold value.

Method and control unit for operating a transmission

A form-locking shift element may include a first shift-element half and a second shift-element half which are engageable with each other by moving at least the first shift-element half. A method for determining an operating condition of the form-locking shift element may include monitoring a position of the first shift-element half with a sensor, and, when a value of a signal generated by the sensor is greater than an applicable value and when the first shift-element half is actuated and displaced towards an engaged operating condition, determining that the shift element is sufficiently engaged to transmit a torque at the form-locking shift element. The applicable value corresponds to a defined overlap between the first and second shift-element halves that is less than an overlap when the first shift-element half is in the engaged operating condition.

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Friedrichshafen, Germany

Christian Pannek