Zf Friedrichshafen Ag

Jörg Arnold

Peter Ziemer

Klaus Steinhauser

Thilo Schmidt

Christian Popp

Gabor Diosi

Christoph Margraf

Jens Weller

Georg Mihatsch

Valentine Herbeth

Andreas Schmidt

Ulf Lang

Jürgen Blaser

Christoph Hess

Johannes Brockmann

Fabian Lebherz

Matthias Wild

Paul Myszka

A transmission between a drive aggregate and a drive output of a vehicle drivetrain has a hydrodynamic starting element and a powershiftable main transmission with a plurality of forward gears, at least one reversing gear, a transmission input, a transmission output, and frictional shifting elements. In each gear a first number of shifting elements are closed and a second number of shifting elements are open. A downstream range group has at least one interlocking shifting element which can be shifted between a first and second driving ranges. With the drive aggregate running, the vehicle at a standstill or nearly so, the main transmission in neutral, and a shift request received to change the downstream range group, shifting elements of the main transmission are actuated, thereby bracing the transmission input against a transmission housing and decoupling the transmission input from the transmission output. The downstream range group is then shifted.

Method and control apparatus for operating a transmission of a motor vehicle

The invention relates to the actuation of a converter lock-up clutch () of a hydrodynamic torque converter () in a vehicle drive-train by means of a safety function where, in addition to a driving strategy function, the safety function can actuate the converter lock-up clutch () by issuing a clutch actuation command. For this purpose, at least one rotation speed at the torque converter () is monitored. If the monitored rotation speed is below a rotation speed threshold, the safety function commands an actuation of the converter lock-up clutch () in its opening direction.

Actuation of a converter lock-up clutch of a hydrodynamic torque converter by means of a safety function

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 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 for terminating a gearshift for an automatic transmission for a motor vehicle is provided, wherein a positive-locking shifting element is involved. After the initiation of the gearshift, there is an evaluation of the continuous signals of at least one control unit of the vehicle, which affect the engine torque and thus the turbine speed gradient. Based on the evaluation of the signals, an upcoming change to the turbine speed gradient that exceeds a first predetermined threshold value or falls short of a second predetermined threshold value is detected, and, upon such detection, the gearshift is terminated.

Method for terminating a gearshift for an automatic transmission for a motor vehicle wherein at least one positive-locking shifting element is involved

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

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Immenstaad, Germany

Jörg Arnold