Zf Friedrichshafen Ag

Jürgen Blaser

Markus Eisele

Ulf Lang

Harry Nolzen

Fabian Ley

Jörg Arnold

Sascha Fiesel

Jens Weller

Franz Sorg

Jens Winter

Thomas Vogt

Matthias Wild

Harm Adams

Yvonne Wiegand

Wolfgang Rapp

Paul Myszka

Fabian Lebherz

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

A transmission is between a drive aggregate and a drive output of a vehicle drivetrain and includes a hydrodynamic starting element and a powershiftable main transmission having a plurality of forward gears and at least one reversing gear. The main transmission has frictional shifting elements, where in each gear a first number of shifting elements are closed and a second number of shifting elements are open. A downstream range group is connected downstream from the main transmission and has at least one interlocking shifting element that can be shifted between first a second driving ranges. With the drive aggregate running, the motor vehicle at a standstill or nearly so, and the main transmission in neutral, a shift request to change the downstream range group is received. The shifting elements of a reversing gear are at least partially closed, and the driving range of the downstream range group is then changed.

A motor vehicle transmission is connected between a drive aggregate and a drive output, and includes a powershiftable main transmission group with a plurality of forward gears and at least one reversing gear. A hydrodynamic starting element is connected between the drive aggregate and the transmission. The main transmission has frictional shifting elements of which, in each gear, a first number are closed and a second number are open. The main transmission has a parking lock that, when engaged, immobilizes an output shaft of the main transmission group. A downstream range group includes at least one interlocking shifting element and can be shifted between a first range and a second range. When the motor vehicle is stationary with the drive aggregate running, to shift the downstream range group the parking lock is first engaged, and then the downstream range group is shifted into neutral from a range to be disengaged.

Method and control apparatus for operating a motor vehicle

Disclosed is a method for operating a multi-gear vehicle transmission having a plurality of shifting elements (A, B, C, D, E) for engaging the gears of the vehicle transmission, where, in a neutral gear an input (AN) and an output (AB) of the vehicle transmission are decoupled from one another, and where, in a driving gear the input (AN) and the output (AB) of the vehicle transmission are coupled to one another in order to propel the vehicle, by closing at least one shifting element (B). When the neutral gear is engaged, at least an actuation condition of a vehicle brake () and a transmission condition with elevated drag losses are detected, where, when the neutral gear is engaged, the shifting element (B) for the driving gear is vented if it is recognized that the vehicle brake () has been released and the transmission condition with elevated drag losses pertains.

Operation of a multi-speed vehicle transmission

Disclosed is a method for operating a multi-speed vehicle transmission having a plurality of shift elements (A, B, C, D, E) for engaging the gears of the vehicle transmission. The method includes decoupling between an input (AN) and an output (AB) of the vehicle transmission in a neutral gear, and coupling the input (AN) and the output (AB) of the vehicle transmission in a drive gear for propelling the vehicle by closing at least one shift element (B). At least one transmission state is determined when the neutral gear is engaged, where a shift element (D) for a reverse gear of the vehicle transmission is closed at least partially if the transmission is in a state with increased drag losses when the neutral gear is engaged.

Method and control apparatus for operating a multiple-speed vehicle transmission

A method for operating a drive-train of a motor vehicle with a drive aggregate in the form of a hybrid drive system () which comprises at least one electric machine (), an internal combustion engine (), a transmission (), a drive output () and a brake system which comprises at least one wear-free permanent brake (). When a braking torque is required, the braking torque is distributed between the electric machine () and the wear-free permanent brake (). At the beginning of a braking torque demand, the required brake torque is provided exclusively by the electric machine (). Thereafter, as a function of characteristics of the wear-free permanent brake, the braking torque demand is transferred, in a controlled manner, from the electric machine to the wear-free permanent brake () so that the sum of the braking torques provided at the drive output () corresponds to the required braking torque.

Method for operating a drive train

A method of shifting an automatic transmission of a motor vehicle having a hydrodynamic converter (). The method comprising the steps of detecting a presence of predetermined stopping conditions; determining that a driver of the motor vehicle intends to cause the motor vehicle to change from a driving state to a stopped state, based on the presence of one of the predetermined stopping conditions; and automatically shifting the automatic transmission () into a standby mode, before the driving state has concluded. The shifting into the standby mode typically occurs when a rotational speed of the hydrodynamic converter () decreases to less than a rotational speed () of a motor and the retarder apparatus (), of the automatic transmission, is disengaged no later than a time by which shifting into the standby mode occurs.

Method for shifting a motor vehicle automatic transmission with a hydrodynamic torque converter when the vehicle comes to a stop

A method of influencing an automated transmission of a motor vehicle having a tractional resistance detection unit, the method comprising the steps of reading data, via the tractional resistance detection unit, containing at least information about a torque of a drivetrain, a rotational speed of the drive train, and an acceleration of the vehicle, determining the external tractional resistance of the vehicle based upon the read data, and influencing the shift program by at least one of activation, adaptation and variation of the shift program, on a basis one of an actual and a statistically prepared data about the external tractional resistance of the vehicle.

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Meckenbeuren, Germany

Jürgen Blaser