Zf Friedrichshafen Ag

Christoph Ruechardt

Mario Steinborn

Roland Mair

Jochen Breuer

Melchor Moro-Oliveros

Thomas Jaeger

A method of controlling an automated transmission with positioning cylinders () controlled by shift valves or venting valves (). At least one cut-off valve () is positioned in front of the shift or venting valves and a control device controls the valves while pressure pipes, which follow the cut-off valve (), are connected with one another following the cut-off valve (). Due to the fact that the cut-off valve (), for reasons of design simplicity and cost, is generally designed as a simple 2/2 way valve which only allows pressure increase but not pressure reduction, the method provides control of the shift valves or ventilation or venting valves (), of a non activated positioning cylinder (), so that the pressure pipe system is connected with an outflow pipe () for a pressure reduction in the pressure pipe system ().

Method for controlling an automated transmission

A method of controlling an automated transmission for motor vehicles with one or several pressure activated positioning cylinders (), via the assigned shift valves (), at least one main cut-off valve () which is positioned prior to the shift valves, and a control device for controlling the shift and main cut-off valves. The pressure requests, for the shifting, are determined and the respective main cut-off valves are triggered depending on the determined pressure requests. To enable a variable match of the supply pressure during transmission shifts, respective optimized pressures or pressure patterns are determined for certain shift scenarios which, for instance, consider a mass to be synchronized, the existence of a tooth-on-tooth position, or the like. Through this method, for instance, the load on shift elements, the shift timing, and the shift noise can be positively influenced.

A method of controlling a transmission brake of an automated change-speed transmission having a control cylinder, that is pressurized by inlet and outlet valves, and an upstream main cut-off valve by which a nominal pressure, supplied to the control cylinder, is regulated. Functional deviations of the transmission brake can be considered during a shifting operation, when the transmission is in neutral, the motor coupling clutch is disengaged and the transmission brake is engaged. The rotational speed gradient and the mass of the transmission components to be braked are determined and used to calculate the current braking torque of the transmission brake. The current braking torque relates to the current regulated nominal pressure, and the determined values are stored in a control unit and used during subsequent actuation of the transmission brake.

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Bodolz, Germany

Christoph Ruechardt