Zf Friedrichshafen Ag

Klaus Steinhauser

Christian Popp

Thilo Schmidt

Peter Schiele

Jorg Arnold

Georg Gierer

Valentine Herbeth

Bernd Allgaier

Walter Hecht

Frank Worms

Hansj&ouml;rg Rosi

Armin Gierling

Jörg Arnold

Bernd Zänglein

Stéphane Klein

Georg Mihatsch

Michael Sohler

Christian Schwemer

Wolfgang Netzer

Stephane Klein

Bernd Zaenglein

Gerald Klein

Peter Ziemer

Gabor Diosi

Christoph Margraf

Andreas Schmidt

Falko Platzer

Reinhard Vollmar

Christian Villing

Jens Weller

Valentine Vincent

Christoph Braun

Sven Diebold

Armin Thiele

Manfred Scholz

Wolfgang Kösling

Ruben Cüppers

Joerg Arnold

Wolfgang Wiest

Dirk Morbitzer

A method of operating a transmission which is shifted to various operating conditions by engaging shifting elements. At least one of the shifting elements is an interlocking shifting element which has to be engaged to obtain at least one defined operating condition of the transmission during which force flows between an input and an output shaft. When a command is received to engage the interlocking shifting element, a rotational speed of the transmission input shaft is displaced in the direction toward a synchronous rotational speed produced in the engaged operating condition of the interlocking shifting element at least as a function of the rotational speed of the transmission output shaft. When the variation of the rotational speed of the transmission input shaft crosses a predefined rotational speed threshold, the interlocking shifting element is actuated in its engaging direction.

Procedure for operating a transmission device

A method for operating a drive train that includes a converter as the start-up element, an automatic transmission, and an output, whereas, after start of the drive unit, the rotational speed of a turbine of the converter is monitored, whereas, if it is determined that, within a defined first time frame after the start of the drive unit, the rotational speed of the turbine reaches or exceeds a first threshold value, a properly filled converter is inferred. If, within the defined first time frame, the rotational speed of the turbine falls short of the first threshold value, an improperly filled converter or a converter that has run empty is inferred.

Method and control device thereto for operating a powertrain

A method is provided for the operation of an assembly of a vehicle, whereas the assembly is transferable from an unactuated position into an actuated position by a pressure medium-actuated actuator if two redundant pressure medium valves both occupy a pressure supply position. For the functional test of one of the valves, a first valve is controlled to occupy the pressure supply position, and the second valve is controlled so as not to occupy the pressure supply position. If, upon this control of the two valves at the pressure medium-actuated actuator or at the assembly to be operated by the pressure medium-actuated actuator, no reaction is detected, there is a correct operation at a proper second valve. If, despite this control of the two valves, at the pressure medium-actuated actuator or at the assembly to be operated by the pressure medium-actuated actuator, a reaction is detected, there is an improper operation at a defective second pressure medium valve.

Method and control unit for the operation of a parking brake of a vehicle transmission assembly

A method of operating a transmission which is shifted to various operating conditions by engaging shifting elements. At least one of the shifting elements is an interlocking shifting element which has to be engaged to obtain at least one defined operating condition of the transmission during which power flows between an input and an output shaft. When a command is received to engage the interlocking shifting element, a rotational speed of the transmission input shaft is displaced in the direction toward a synchronous rotational speed produced in the engaged operating condition of the interlocking shifting element at least as a function of the rotational speed of the transmission output shaft. When the variation of the rotational speed of the transmission input shaft crosses a predefined rotational speed threshold, the interlocking shifting element is actuated in its engaging direction.

A method of operating a transmission device having gears that are engaged by actuating shifting elements. At least one of the shifting elements is an interlocking shifting element which has to be engaged in at least one gear to transmit drive between an input and an output shaft. When a command is received to engage the interlocking shifting element, a rotational speed of the input shaft is displaced in the direction toward a synchronous rotation speed produced in the engaged operating condition of the interlocking shifting element at least as a function of the rotational speed of the output shaft. The engagement process of the interlocking shifting element from its disengaged operating condition is discontinued if, before reaching the synchronous rotational speed, the variation of the rotational speed of the input shaft crosses a predefined rotational speed threshold without initiating engagement of the interlocking shifting element.

In a method for operating an automatic transmission having multiple frictional-locking shifting elements and at least one positive-locking shifting element, for the representation of a transmission ratio stage, at least three shifting elements are closed. For a shifting process between two specified transmission ratio stages, at least two shifting elements are opened and at least two shifting elements, including at least one positive-locking shifting element and at least one frictional-locking shifting element, are closed. In the chronological sequence of the shifting process, the closing of the positive-locking shifting element takes place only after all frictional-locking shifting elements are closed.

Method for operating an automatic transmission

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 for detecting a malfunctioning shift element in an automatic transmission is provided. The method includes operating the automatic transmission in an intermediate gear. A selected shift element of the automatic transmission is commanded to a disengaged configuration in the intermediate gear. The method also includes measuring a gear ratio of the automatic transmission while the automatic transmission is operating in the intermediate gear, and determining whether the selected shift element of the automatic transmission is malfunctioning based at least in part on the gear ratio of the automatic transmission in the intermediate gear.

Method for detecting a nonoperational shift element in an automatic transmission

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 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 controlling the system pressure in an automatic transmission having interlocking shifting elements in which, during shifts and gear engagement and gear disengagement processes involving interlocking shifting elements, as a function of the engagement and disengagement times of the interlocking shifting elements involved and the shift conditions of the frictional shifting elements involved, the system pressure is increased to an elevated pressure that enables rapid engagement or disengagement of the interlocking shifting elements, in such manner that the system pressure is increased in at least two phases whose timing depends on the shift conditions of at least one of the shifting elements involved.

Line pressure control method for a transmission having a dog clutch

A method of actuating a form-locking shift element of a transmission. To shift from a current gear to a target gear, an actuation time is determined for the locking shift element to be engaged during a gear shift depending on a reaction time of the assemblies participating during actuation of the locking shift element, an engaging time of the locking shift element, and at least one filtered signal such that the locking shift element is engaged within a specified rotational speed window encompassing a specified differential rotational speed. It is verified whether the locking shift element can be engaged within the specified rotational speed window depending on at least one unfiltered signal, and, if the locking shift element can be engaged within the specified rotational speed window, the actuation is unaffected; conversely, if the locking shift element cannot be engaged within the specified rotational speed window, the actuation is affected.

Method and control device for controlling a positively locking shift element of a transmission

A method of monitoring an emergency condition in an automatic transmission, with which, by comparing a theoretical with an actual rotational speed, measured on the transmission input side, overlap of the activated emergency condition, with a gear engagement process called for during the normal condition, is prevented.

Method for checking an emergency condition in a transmission system

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 for shifting an automatic or an automated transmission of a motor vehicle to a 'neutral' position such that the shift position of the transmission and a parking lock, provided for keeping the motor vehicle stationary, are engaged as a function of a shift position selected with a driver operated selector device and as a function of other operating parameters of the motor vehicle. A holding phase, in which the transmission is in the neutral position, free from friction force locking, can be activated by a separate operating device which is provided, in addition to the selector device, but only when the motor vehicle is simultaneously at least approximately stationary, an ignition current circuit that acts on a drive engine of the motor vehicle is electrically interrupted, and the 'neutral' (N) shift position is specified by a selector device.

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Kressbronn, Germany

Klaus Steinhauser