Zf Friedrichshafen Ag

Valentine Herbeth

Jorg Arnold

Klaus Steinhauser

Georg Mihatsch

Thilo Schmidt

Christian Popp

Gabor Diosi

Christoph Margraf

Andreas Schmidt

Jörg Arnold

Peter Ziemer

Ruben Cuppers

Joerg Arnold

A method of determining a fill current value of a converter lock-up clutch of an automatic transmission. The automatic transmission comprises a hydrodynamic converter, at which a speed ratio arises, and an output shaft. In a control sequence with the output shaft being stationary, the speed ratio is influenced by changing the control current, and the fill current value is determined from the progression of the speed ratio arising, during the control sequence, in conjunction with the progression of the control current.

Method for determining characteristics of an automatic transmission

A method of operating a vehicle drive-train comprising an internal combustion engine and a transmission system functionally connected to the internal combustion engine. The transmission has an interlocking shifting element, one shifting element half of which is functionally connected to the transmission input shaft while the other shifting element half is functionally connected to a transmission output shaft. Upon receipt of a command to change the transmission from a neutral position, in which a force flow through the transmission is interrupted, to an operating condition, in which the force flow through the transmission is produced, the interlocking shifting element is changed to an engaged operating condition. A speed difference between the shifting element halves is brought by varying the speed of the internal combustion engine into a speed difference window within which the interlocking shifting element can be changed to its engaged operating condition.

Method for operating a vehicle drive train having an internal combustion engine

A method of determining a fill current value of at least one frictionally engaging shift element of an automatic transmission. The automatic transmission includes a hydrodynamic converter at which a speed ratio arises and an output shaft. In a control sequence, with a stationary output shaft, the speed ratio is influenced by changing a control current, and the fill current value is determined from the progression of the speed ratio arising during the control sequence, in conjunction with the progression of the control current.

A method of operating a transmission of a vehicle drive-train when a gearshift from a current gear toward a target gear has been requested. The transmission having frictional shifting elements and at least one interlocking shifting element. If an actuating electrical current, equivalent to a closed operating condition of the frictional shifting element to be engaged, and an actuating electrical current, equivalent to an open operating condition of the interlocking shifting element to be disengaged, are determined while, at the same time, a closed operating condition of the interlocking shifting element to be disengaged is detected by a sensor, a fault is recognized. If the fault is recognized during a predefined test period, one or more selected shifting elements are disengaged and a force flow in the transmission is interrupted. Alternatively, by disengaging the frictional shifting element to be engaged, the current gear is engaged in the transmission.

Method for the operation of a transmission device in a vehicle drive train when a request is made to change gears

When a request is made to change gears, the form-fitting shifting element being disengaged, for the requested gear change, is disengaged at a predefined target disengagement moment following the target disengagement moment. When the gear is actually changed, an actual disengagement moment is determined based on when the form-fitting shifting element begins disengaging and a transmission operating state variable. If there is a deviation between the actual moment and the target moment of disengagement, then the target disengagement moment is modified by a time value, and the moment when the form-fitting shifting element begins to be actuated is shifted in time in relation to the target moment of disengagement and/or actuation of the shifting element to be connected is adjusted to a determined characteristic of the operating state of the form-fitting shifting element to be disconnected such that it is disengaged approximately at the target disengagement moment.

Method for the operation of a transmission device in a vehicle drive train, comprising at least one form-fitting shifting element and multiple frictionally engaged shifting elements

A method of operating a transmission device () having a plurality of frictionally engaging shift elements (B, C, D and E) and at least one form-locking shift element (A, F) for implementing different transmission ratios. Upon a requested change in operating state of the transmission device (), the at least one form-locking shift element (A) is transferred into an at least nearly load-free state, during which the form-locking shift element (A) is transferred from an engaged to a disengaged operating state by increasing the transfer capability of at least one frictionally engaging shift element (E), which is not engaged in the power flow of the transmission device () either to represent the present operating state or to represent the requested operating state.

Method for operating a transmission device having a plurality of friction-fit shift elements and at least one form-fit shift element

A method of operating a transmission device comprising friction-locking and form-locking shift elements for obtaining different gear ratios. A shift request for engaging a shift element undergoes a time delay dependent upon an operating state prior to a time of engagement of the shift element. A rotational speed differential between halves of the shift element lies within a rotational speed differential window required for the engagement procedure is assigned to the time of engagement. A gradient of the transmission input speed is ascertained at the time of the shift request, and the actual gradient is subsequently monitored and compared with the gradient that existed at the time of the shift request. If an absolute deviation greater than a threshold value is ascertained, the time delay is changed or an actuation of another shift element to be disengaged is varied such that the deviation is reduced below the threshold value.

Method for operating a transmission device with a plurality of friction-locking and positive-locking shifting elements

A method of operating a vehicle drive-train with an engine and a transmission during a gearshift in which an interlocking shift element is disengaged and a frictional shift element is engaged. Upon a shift command, the shifting time and a transmission input speed are monitored. If the input speed deviates from a synchronous speed equivalent to the gear ratio being disengaged, recognizing disengagement of the interlocking shifting element. If an engaged operating condition of the interlocking shifting element to be disengaged is detected, after the lapse of a time interval beginning with the shift command, a current drive torque of the drive machine is brought by motor actuation to a level that corresponds to a difference between the current transmission input torque and a torque that can be transmitted by the frictional shifting element to be engaged, operating with slip, plus a torque offset value.

Method for operating a vehicle drive train

A method of operating a vehicle drive train having a drive machine, a transmission apparatus having a plurality of shift elements and an output drive. The plurality of shift elements are engaged or disengaged in a power flow for achieving different transmission ratios within the transmission apparatus. The output drive is coupled to a transmission output shaft and the drive machine is coupled to a transmission input shaft of the transmission apparatus. Upon a request to interrupt power flow within the transmission apparatus, between the transmission input shaft and the transmission output shaft, a maximum number of shift elements are transferred to and/or held in an engaged operating state, and the remaining portion of the shift elements are transferred to and/or held in a disengaged operating state with the transmission output shaft being rotatable.

Method for operating a vehicle drive train having a driving machine and having a transmission apparatus having a plurality of shift elements

A method of operating a transmission of a vehicle drive train with at least one drive machine. The transmission is formed with at least one interlocking shift element and a plurality of frictional shift elements in order to obtain various gear ratios. During an engaging process of the interlocking shift element, starting from a disengaged operating condition, in which halves of the interlocking shift element are out of engagement, to an engaged operating condition, in which the shift element halves are interlocked in a rotationally fixed manner, when interlock between the shift element halves is obstructed, a rotational speed difference is produced at least temporarily between the shift element halves, at which the interlock in the area of the interlocking shift element can be engaged. To produce the speed difference between the shift element halves, the transmission capacity of at least one frictional shift element is increased.

Method for the operation of a transmission device of a vehicle drive train

A method is described for the operation of a transmission device () with a plurality of frictional shift elements (A, D, E, F) and at least one interlocking shift element (B, C) for obtaining various gear ratios. When a command is received for a gearshift during which the interlocking shift element (C) has to be changed from an open to a closed operating condition, the interlocking shift element (C) is at least approximately synchronized by increasing the transmission capacity of at least one frictional shift element (A) which does not have to be engaged in the force flow either to obtain the gear ratio that is to be disengaged or to obtain the gear ratio that is to be engaged.

Method for the operation of a transmission device

A method of operating a transmission () with at least one interlocking shift element (F) having at least two shift element halves that can be brought into interlocked engagement with one another. When a command is received to close the interlocking shift element (F), a current rotational speed difference between the shift element halves of the interlocking shift element (F) and the current positions of the shift element halves are determined. If the rotational speed difference is smaller than a first speed difference threshold value and if a tooth-on-tooth position has occurred at the interlocking shift element (F), then to release the tooth-on-tooth position, the actuation force is changed to a release level at which a rotational speed difference above a second speed difference threshold value is produced between the shift element halves.

Method for operating a transmission with at least one positive-locking shifting element

A method of operating a vehicle drive train with a drive machine and a transmission device during a coasting upshift, during which at least one interlocking shift element that is engaged in the force flow of the transmission device, to produce the gear ratio to be disengaged, is disengaged from the force flow, and a frictional shift element that has to be engaged, in the force flow of the transmission device to obtain the gear ratio to be engaged, is engaged in the force flow. When a shift command is given for a gear ratio change, torque applied at the interlocking shift element to be disengaged is reduced to at least approximately zero, by a defined engine intervention, and the interlocking shift element is then disengaged from the force flow of the transmission device.

A method for operating a vehicle drivetrain () having a drive motor (), a transmission () and a drive output (). When a gear ratio change is called for in the transmission (), between an actually engaged gear and a target gear, one of a frictional or an interlock-type shift element is engaged in a flow of force in the vehicle drivetrain () and the other of an interlock-type or a frictional shift element is disengaged from the flow of force in the vehicle drivetrain (). An actual speed that is at least equivalent to a transmission input speed is monitored and an actuation pressure of the frictional shift element involved in the shift operation and/or a torque of the drive motor () is/are varied to change the actual speed to a nominal speed.

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Friedrichshafen, Germany

Valentine Herbeth