Zf Friedrichshafen Ag

Hans Hofler

Thomas Kurz

Wolfgang Rebholz

Karl Kuhner

A method of operating a vehicle drive-train including a drive engine, a transmission device and a drive output. At least one shifting element is provided in the transmission, whose transmission capacity for obtaining an operating condition of the transmission device can at least, in part, be continuously varied. During overdrive operation of the drive-train, torque present at the output can be supported at least partially by the transmission device in the area of the drive engine. During overdrive operation, the transmission capacity of one of the transmission shifting elements, which to obtain the current operating condition of the transmission device is essentially at least approximately zero, is set to a value at which at least part of the torque present at the drive output can be supported in the area of the transmission device, and the rotational speed of the drive engine has a value below a predefined limit value.

Method for operating a vehicle drive train

During reversal of drive of a vehicle, particularly a work machine with a hydrodynamic torque converter and a bypass clutch, the bypass clutch is first disengaged, during the reversal process. Next, a previously engaged first driving direction clutch, driving the vehicle in the first driving direction, is disengaged and a second driving direction clutch, for driving the vehicle in the second driving direction, is engaged so that a speed of the vehicle, in the first driving direction, is reduced and a speed of the vehicle, in the second driving direction, is subsequently accelerated, whereby the drive motor is operated at a higher rotational speed during the reversal process.

Method for reversing the direction of travel of a vehicle

A method of actuating a clutch of a hydrodynamic torque converter in a self-propelling working machine such that when the clutch is engaged and thereby connects a drive input of the hydrodynamic torque converter to a drive output of the hydrodynamic torque converter, and when a service brake is actuated, the clutch is disengaged thereby separating a drive input of the hydrodynamic torque converter from a drive output of the hydrodynamic torque converter. The method comprises the steps of, when the service brake is actuated, actuating the clutch in the engaging direction, and maintaining engagement of the clutch if a device for recognizing a driving status of the working machine detects that the working machine is driving downhill.

Method for actuating a clutch of a hydrodynamic torque converter

A clutch of a hydrodynamic torque converter, which connects the drive input of the hydrodynamic torque converter to the drive output of the hydrodynamic torque converter, is actuated in a disengaging direction when a power at an auxiliary power take-off in a vehicle exceeds a predefined value.

Method for the operation of a clutch of a hydrodynamic torque converter

A clutch of a hydrodynamic torque converter in which the input drive of the hydrodynamic torque converter can be connected to the output drive of the hydrodynamic torque converter. The clutch of the hydrodynamic torque converter is only engaged if a difference between the rotational speeds of the pump and the turbine of the hydrodynamic torque converter is not reached and a predefined distance traveled by the accelerator pedal is exceeded.

A lock-up clutch of a hydrodynamic torque converter remains disengaged during shifts of a downstream transmission, when the drive motor is operated in the partial load range, and remains engaged during shifts of the downstream transmission, when drive motor is operated in a full load range.

Method for controlling a lock-up clutch of a hydrodynamic torque converter

A method of operating the torque converter lock-up clutch in a power transmission of a working machine comprising at least one hydraulically actuated lifting device. The torque converter lock-up clutch is actuated for disengagement when a predefined limit value for the position of the lifting hydraulic mechanism of the at least one lifting device is exceeded. When the position of the lifting hydraulic mechanism falls below a predefined limit value and when the turbine rotational speed exceeds a predefined threshold value, the torque converter lock-up clutch is reengaged.

Method for operating the torque converter lock-up clutch in a power transmission of a mobile machine comprising at least one hydraulically actuated lifting device

A method of actuating an interwheel differential lock of a mobile vehicle. The interwheel differential lock is actuated to engage depending on the speed of the vehicle, the accelerator pedal position and the gradient of the torque at the transmission output.

Method for actuating an interwheel differential locks

A motor vehicle with a parking brake () which, in addition to functioning as a parking brake (), may also be used as an auxiliary brake for assisting the main brake () and/or a sustained-action brake. The parking brake () is preferably incorporated in the transmission () of the vehicle and designed as a rotary disk brake in an oil bath.

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Immenstaad, Germany

Hans Hofler