Zf Friedrichshafen Ag

Stephan Schinacher

Marcus Hiemer

Jan-Frederik Kuhn

Sven Bieber

Jürgen Legner

Rico Glöckner

Migen Bebeti

Matthias Madlener

Mario Brugger

Markus Lukassek

Timo Maise

Stefan Traub

Simon Geiger

Robert Morrison

Matthias Duller

Raphael Zohner

Werner Denk

Andreas Rothmund

A method of controlling an electric drivetrain of a work machine, the method including determining whether a brake pedal actuation has occurred with an actuation distance greater than an actuation distance threshold value for an actuation duration longer than an actuation duration threshold value. The method further includes determining whether no drive torque maintaining condition exists, based on a determination that the brake pedal actuation occurred with the actuation distance greater than the actuation distance threshold value for the actuation duration longer than the actuation duration threshold value. The method further includes generating a control signal for the electric drivetrain to disable a torque generation by the electric drivetrain based on a determination that no drive torque maintaining condition exists.

Method for controlling an electric drivetrain of a work machine, and corresponding control device

A process for determining a setpoint rotational speed of a work machine engine, having a continuously variable transmission, based on operation of power hydraulics. The setpoint rotational speed for highly productive operation is determined, without knowledge current operation of the power hydraulics, by a basic engine speed setting. With knowledge of the current operating state, the setpoint rotational speed is determined by the basic speed settings and low or high engine speed settings. The low speed setting alone determines setpoint rotational speeds that are lower than the basic speed setting or a combination of the low and basic speed settings. The high speed setting alone determines setpoint rotational speeds that are higher than the basic speed setting or a combination of the basic and high speed settings. The speed settings can comprise a setpoint rotational speed range of above a reciprocal transmission range of the variable transmission.

Method for ascertaining the target rotational speed of a drive machine of a work machine comprising a continuously variable transmission and a working hydraulic system

A method of controlling a drive device of a construction machine with a split transmission, which is at least coupled, at an input side, to a drive force source and, on the output side, with a drive range change transmission so as to set at least two shiftable drive ranges. The method includes a detection step (S) for detecting drive dynamic requests for operation of the construction machine and a determination step (S) for determining whether a drive dynamic request with an increased drive dynamic is present. If a drive dynamic request with increased drive dynamics is determined, then a shifting step (S) is executed for shifting the drive range change transmission from a second, of the at least two drive ranges, to a first of the at least two drive ranges, to achieve increased driving dynamics of the construction machine.

Method for controlling a drive device of a construction machine

A method for the operation of a vehicle drive-train of a working machine having a drive motor, a transmission whose transmission ratio can be varied continuously, and a drive output. A rotational speed (nmot) of the drive motor can be varied by the driver, by the driver's actuation of a first control element (), within a rotational speed range () delimited by an upper characteristic line (nmoto) and a lower characteristic line (nmotu). The characteristic lines (nmoto, nmotu) are functions of a reciprocal transmission ratio (irez) of the transmission. Furthermore, the rotational speed (nmot) of the drive motor that can be set by the driver by way of the first control element (), can be influenced by the driver's actuation of a second control element () and as a function of an operating condition of the working machine.

Operating method for a vehicle drive train of a working machine including a drive motor, a transmission and an output

A method for operating a vehicle drive-train having a continuously power-branched transmission with secondary coupling. In the open operating condition of reversing clutches of a reversing gear unit, torque applied in the area of a drive output can be supported by a range group in the area of a variator. In the event of a command to interrupt the power flow between a drive engine and the drive output, it is checked whether the vehicle is on an inclined surface and if the result of that inquiry is positive, the power flow between the drive engine and the transmission is interrupted at the latest when the rotational speed of the drive output is reduced to zero by opening the reversing clutches, while the active connection between the drive output and the variator is maintained by way of the range group.

Method of operating a power path with continuously power-split transmission and with secondarily coupled power split

A method is described for determining a reference value of an actuating current that corresponds to a defined operating point of an electro-hydraulically actuated frictional shifting element of a continuously variable power-branched transmission, at which the shifting element transmission capacity is zero, and starting from which an increase of actuating force immediately increases the transmission capacity. The actuating current reference value of the shifting element, when closed with a further shifting element decoupled from the transmission output and when a transmission input rotational speed is higher than a defined threshold, is reduced until a rotational speed difference between the rotational speeds of the shifting element halves exceeds a predefined limit value such that, at the time when the limit value is exceeded, the reference value of the actuating current is the reference value of the actuating current that corresponds to the defined operating point of the shifting element.

Method for determining a reference value of an actuating current

A device for varying the swept volumes of first and second hydraulic machines, whose swept volumes depends upon pivoting positions of adjustable axes thereof which can be connected to one another by first and second lines. The axes can be coupled to a piston-cylinder device which is adjustable by a control valve unit for pivoting the axes. Pressures in the area of the hydraulic machines can be limited by the control valve unit. The control valve unit can be coupled to a respective first or second line with the highest pressure. A device for determining an existing actual pressure is located upstream of the control valve unit, at least in the area of one of the first and the second lines that connects with the first and the second hydraulic machines. The control valve unit can be actuated based on the actual pressure value determined by the device.

Device for varying the volumes of a first hydraulic machine and a second hydraulic machine

A method for determining a draining behavior of a hydraulically actuated transmission shifting element. By applying actuating pressure, the shifting element is changed from a completely drained, open operating condition to a completely filled closed operating condition, and the reference filling time, until the closed condition has been reached, is determined. Upon recognition of the closed condition, then by adjusting the actuating pressure for a predefined draining time, the shifting element is changed to its open condition and, thereafter, again completely filled and closed. Upon recognition of the closed condition, the shifting element is actuated direction toward the open condition by reducing the actuating pressure. Then, before completely opening, the shifting element is again returned to its closed operating condition and the filling time, until the partially drained shifting element has reached the completely filled and closed operating condition, is determined.

Method for determining the drainage control of a hydraulic switching element of a transmission

A method of operating a vehicle drive-train during a starting process. The drive-train has a drive mechanism which can couple a continuously-variable power-branched transmission in which a plurality of transmission ratios can be engaged. The transmission ratios can be varied continuously by adjusting a variator, the transmission driving a drive output. A force flow between the drive mechanism and the drive output can be produced by a frictional shifting element by appropriately adjusting the transmission capacity of the shifting element. When a start command is issued, a starting transmission ratio is engaged in the area of the transmission device. During the engagement of the starting transmission ratio the transmission capacity of the frictional shifting element is adjusted to values greater than zero.

Method for operating a vehicle drive train during a starting process

An arrangement for a hydraulic eccentric adjustment for setting a predetermined displacement volume in a hydrostatic motor and, in particular a radial piston motor (). The arrangement has an adjustment device which, to position an eccentric element (), can be acted upon with pressure medium via a shuttle valve () such that at least one actuating piston (), of an adjustment cylinder () that can be acted upon on both opposed sides is provided, as the adjustment device. A first pressure chamber () of the cylinder is connected to a first supply line (), for setting a smaller displacement volume while a second opposed pressure chamber () is connected to a second supply line (), for setting a larger displacement volume. The two supply lines () are connected to one another by a connecting line ().

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Egesheim, Germany

Stephan Schinacher