Zf Friedrichshafen Ag

Bernd Döbele

Norbert Wiencek

A shift control method for an automated gearshift transmission arranged in a drivetrain of a motor vehicle, between a drive motor and an axle drive, which is provided with unsynchronized gear clutches and whose input shaft can be connected to the driveshaft of the drive motor by an automatically controllable separator clutch such that, for an upshift, the synchronization of the target gear takes place with the separator clutch disengaged by setting a substantially constant braking torque at a transmission brake in driving connection with the input shaft. In order to speed up the shift sequence, without additional design measures, as the input speed of the gear clutch of the target gear approaches its output speed, to complete the synchronization, the separator clutch is partially engaged and then disengaged again substantially simultaneously as the transmission brake is released.

Shift control method in an automated manual transmission

A device for reducing the drop in tractive force during the gear shifting phase of an automatic transmission comprising an automatically actuated drive clutch. The device comprises a rotary storage device that can be coupled, if necessary via two transmission ratio steps () that are each assigned a friction clutch (), to the output shaft of the transmission or, if the transmission has a downstream range group, to the output shaft of the main friction transmission. Only one of the two friction clutches () can be activated at any time, and a step up ratio can be achieved and the rotary storage device can be loaded with one of the transmission ratio steps (). A step down ratio can be achieved and energy can be released from the rotary storage device to the output shaft using the other transmission ratio step ().

Device for reducing the drop in tractive force

A method and a device for controlling starting, driving and shifting processes of a motor vehicle with a drive motor () and a gearshift (), which can be brought into effective drive connection with one another using a starting and shifting clutch (), with a clutch actuation device () as well as with a control apparatus () which stands in connection with a power element of the same for controlling the power of the drive motor (), and which is connected using signal engineering with sensors () which ascertain an accelerator deflection angle (A), a motor rotational speed (C) and a transmission input shaft rotational speed (E).

Method and device for the control of starting driving or switching processes on a motor vehicle

A drive device for a transmission (), a main engine and a shifting clutch (). In order to reduce the phase of tractive force interruption during switching operations, the drive device has a shifting brake clutch (), located between the engine and the shifting clutch, such that during switching operations, intersecting disengaging and engaging processes of both clutches (or), provide for support of the main engine torque in a gear output ().

Drive device comprising a gearbox

A motor vehicle for controlling an automatic gearshift stepped variable speed transmission that can be driven by a drive engine, in which, depending on an accelerator pedal position and an engine speed, upshifts or downshifts between the gear steps are triggered automatically and in which a kick-down switch is present. In a first speed range below a first boundary speed (n) actuation of the kick-down switch triggers a downshift. For one or more upper gear steps in a second engine speed range above a second boundary speed (n_KD_Schw), even at high loads, no downshifts is triggered and an upshift is only triggered by actuation of the kick-down switch.

Method for triggering an upshift during kick-down conditions

In an automated multi-group transmission consisting of one front-mounted group, one main group and one range group and in which the front-mounted group transmission and the range group transmission comprise a first shifting position for a low-speed total transmission ratio, a second shifting position for a high-speed total transmission ratio and a third shifting position as neutral position for interrupting the torque transmission, in a gear-shifting method for gear change, the range group transmission and the front-mounted group transmission are simultaneously brought to their respective neutral shifting position, which makes it possible to shift a deceleration of the main transmission. With the start of the gear-shifting process in the neutral positions, there also begins the control of the engine rotational speed to the total ratio of the target gear.

Gear-shifting method for multi-group gearboxes

A method for controlling the gear release in an automated multi-speed drive in a vehicle drive with a drive motor and a separating clutch positioned between the drive motor and the multi-speed drive that the events 'application of a shifting power' and 'opening of the separating clutch' are determined dependent on reaching certain vehicle accelerations (a, a). The vehicle acceleration (a) decreases at the beginning of the shifting process due to the reduction of the fuel injection quantity (EM) supplied to the drive motor.

Growing community of inventors

Salem, Germany

Bernd Döbele