Zf Friedrichshafen Ag

Zf Friedrichshafen

Zf Freidrichshafen Ag

Peter Schiele

Klaus Steinhauser

Bernd Allgaier

Thilo Schmidt

Christian Popp

Georg Gierer

Johannes Kaltenbach

Peter Ziemer

Friedrich Tenbrock

Michael Gromus

Michael Sohler

Christian Schwemer

Johannes Brockmann

Harald Stehle

Günther Maier

Ralf Dreibholz

Gert Bauknecht

Stefan Blattner

Gerd Frotscher

Falko Platzer

Stefan Kilian

Franz-Josef Schuler

Linus Eschenbeck

Thorsten Müller

Peter Spoerl

Magnus Stiefenhofer

Oliver Gloge

Thomas Lindner

Armin Thiele

Klaus Habe

Ruben Cüppers

Ulrich Dorr

Ewald Ast

Philipp Fehr

Frank Gethöfer

Martin Neumann

A method for operating a vehicle having a vehicle drive train () and a vehicle brake () downshifting an automatic transmission () in a coasting condition, during which at least one friction-locking shift element is to be disengaged and one form-fit shift element is to be engaged. An output torque present at a driven end () is at least partially supported at a drive motor () at the point in time of a demand for the coasting downshift. The drive motor () is actuated before the implementation of the coasting downshift in order to reduce the portion of the output torque which is supportable at the drive motor (), and a portion of the output torque is supported in the area of the vehicle brake () by an appropriate actuation of the vehicle brake ().

Method for operating a vehicle with a vehicle powertrain and a vehicle brake

A gearbox () includes an input shaft () and a first and a second proportionally controllable shift element (A to F). The shift elements (A to F) are configured to control, by way of an open-loop system, engagement or disengagement of a gear ratio in the gearbox (). A method () for the open-loop control of the gearbox () includes: determining a specified differential speed profile that is a profile of a difference between a rotational speed of the input shaft () and a synchronous speed of a gear ratio to be engaged; and determining a torque demand of a drive source connected to the input shaft () or determining a control profile for the one of the first and second shift elements (A to F) to be engaged in the gear ratio on the basis of the specified differential speed profile.

Transmission control system

A method () for the open-loop control of a gearbox () that includes a first and a second proportionally controllable shift element (A-F) is provided. The method includes disengaging () the first shift element (A-F) according to a first control profile and engaging () the second shift element (A-F) of the gearbox () according to a second control profile. The first control profile includes a first variable portion which is determined as a function of a temperature of the gearbox ().

Transmission control

A method () for the open-loop control of a gearbox () that comprises an input shaft () and a first and a second proportionally controllable shift element (A-F) is provided. The method includes disengaging () the first shift element (A-F) according to a first control profile and engaging () the second shift element (A-F) according to a second control profile. The method also includes cyclically performing the following during the disengagement and the engagement: determining () a difference between the rotational speed of the input shaft () and a rotational speed which the input shaft () assumes when the second shift element (A-F) has been completely engaged; determining () a gradient of the difference; and adapting () the first control profile on the basis of the gradient.

A method for operating a vehicle drivetrain () includes proceeding, in the presence of the demand for activation of the engine start-stop function of the vehicle drivetrain () and a simultaneously shut-down drive machine (), from an operating state of the vehicle drivetrain () during which a sailing operating function of the vehicle drivetrain () is active, during which the drive machine () is decoupled from the drive output (), during which the positively engaging shift element (F) is open and during which a rotational speed (n_ab) of the drive output () is higher than a defined rotational speed at which a rotational speed difference between shift element halves of the positively engaging shift element (F) lies within a rotational speed range within which the positively engaging shift element (F) is transferrable into the closed operating state, and actuating the positively engaging shift element (F) in a closing direction no later than when the defined rotational speed is reached.

Method for operating a vehicle drive train with a drive motor, an output and a transmission which is arranged between the drive motor and the output

A method for operating a vehicle drivetrain () having a drive machine (), an output () and a gearbox () with the gearbox () arranged in power flow between the drive machine () and the output () includes opening, in the presence of a demand for activation of a sailing operating function of the vehicle drivetrain () and a simultaneously activated engine start-stop function, a positively engaging shift element (F) while the drive machine () is left both decoupled from the output () and shut down.

Method for operating a vehicle drive train

A method for operating a vehicle drivetrain () includes decoupling, in the presence of a demand for realizing a sailing operating state of the vehicle drivetrain () during which a drive machine () is active and the power flow between the drive machine () and a drive output () is disconnected in a gearbox (), the active drive machine () from the drive output () by opening of one of a plurality of shift elements (A to F) that is held in a closed operating state in order to realize the operating state present before the demand for decoupling of the active drive machine (). The method also includes then actuating the plurality of shift elements (A to F) in a manner dependent on the present operating state profile of the vehicle drivetrain () and with the active drive machine () decoupled from the drive output ().

A hydraulic control device for an automatic transmission including a valve device. The valve device comprising a switching valve, featuring a switching component and a check valve. The switching valve is formed in a housing and is hydraulically connected to a first pressure adjusting device and a second pressure adjusting device along with a shift element for transferring a certain torque. The switching valve is formed as a directional seat valve.

Hydraulic control arrangement for an automatic transmission

A hydraulic control device for an automatic transmission for a motor vehicle includes a shiftable throttle valve allocated to one or more shift elements of a plurality of hydraulically actuated shift elements. The shiftable throttle valve hydraulically connects a respective pressure-adjusting device of the one or more shift elements to a respective clutch cylinder of the one or more shift elements. The shiftable throttle valve is shiftable into at least a first shift position and a second shift position. A hydraulic resistance between a hydraulic transmission controller and the one or more shift elements of the plurality of hydraulically actuated shift elements is larger in the second shift position relative to the first shift position.

Hydraulic control device for an automatic transmission

A method for operating a vehicle drive train includes operating the vehicle drive train with a drive unit switched on, with the drive unit connected to an output by a transmission, and with a positive-locking shifting element open. In response to a coasting operating state request for the vehicle drive train and a rotational speed of a transmission output being greater than a threshold, the drive unit is switched off and power flow between the drive unit and the output is interrupted by opening at least one of a plurality of frictional-locking shifting elements. The method also includes closing the positive-locking shifting element during the coasting operating state and no later than a leave coasting operating state request.

Method for actuating a vehicle powertrain

A transmission device has at least one electro-hydraulic transmission control unit and a method of operating the transmission device having a plurality of gear wheel that can be engaged and disengaged from a force flow by fluidically actuated shifting elements. A piston space of a first shifting element, delimited by a second functional surface of the actuating piston of the first shifting element, is made separate from a piston space of a second shifting element, delimited by the first functional surface of the actuating piston, and an area of the second shifting element, that carries an actuating pressure, or an area of the first shifting element, that carries an actuating pressure, is, or can be, connected to the piston space delimited by the second functional surface of the actuating piston of the first shifting element.

Transmission device and method for operating a transmission device

A method for operating an automatic transmission of a motor vehicle, whereas the automatic transmission features several interlockable shifting elements, involves determining, from the data made available from the driving operation of the motor vehicle, a change to consumption of the motor vehicle expected to be caused by an activated interlocking of the shifting elements and a change to the shifting dynamics of the motor vehicle expected to be caused by an activated interlocking of the shifting elements. The changes are evaluated such that, depending on the change to consumption and depending on the change to shifting dynamics, an interlocking of the shifting elements is permitted or not permitted.

Method and control device thereto for operating an automatic transmission

A method of operating a drive train having a hybrid drive including a combustion engine and electric motor, a clutch located between the engine and the motor, a transmission, a starting element and a brake pedal. For electric crawling from a state in which the clutch is disengaged, the brake pedal is activated and the combustion engine is turned off, initially the starting element is brought to or maintained at a filling pressure. Next, the rotational speed of the electric motor is adjusted to be higher, by a defined slippage rotational speed, than a transmission side rotational speed. When this slippage is reached, the starting element is further engaged to create a crawl torque at the output. The electric motor continues at rotational speed control so that the slippage is maintained.

Method for operating a drivetrain

An automatic transmission of a motor vehicle driven by an internal combustion engine with a transmission oil circuit, a main oil pump, mechanically driven by a combustion engine, and an auxiliary oil pump () that can be electrically driven and is located inside an oil sump (). It is proposed that the auxiliary oil pump () is arranged transversely with respect to the travel direction (x) of the motor vehicle.

Automatic transmission for a motor vehicle

A method of operating a vehicle hybrid drive train comprising an internal combustion engine and electric machine whose torque is applicable to a drive output of the drive train. The drive train comprises a clutch arranged between the internal combustion engine and electric machine, an oil pump connected in the drive train downstream of the clutch in relation to the internal combustion engine, and the oil pump can be driven by the internal combustion engine and the electric machine, and a transmission which comprises a shifting elements for producing various gear ratios and which is supplied with hydraulic fluid by the oil pump in an operating-status-dependent manner. The speed of the electric machine is set independently of the speed of the internal combustion engine, in order to supply the transmission with a flow of a volume hydraulic fluid required for the operating point of the transmission present at the time.

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Kressbronn, Germany

Peter Schiele