Zf Friedrichshafen Ag

Adolf Bucher

Franz-Josef Schuler

Anton Fritzer

Tobias Pfleger

Wolfgang Vallaster

A device for the hydraulic control of an automatic transmission, especially a continuously variable automatic transmission. The control system comprises a forward/reverse drive unit (), which is controlled by way of at least a first and a second shifting component (). The shifting components () are in turn controlled via at least two valves (), which are pressurized by way of a pressurized medium pump (). A gear selector device () selection is made among at least a forward gear (D), a neutral gear (N) and a reverse gear (R), wherein the selector device () possesses a non-mechanical connection to the transmission control system.

Device for controlling an automatic transmission

A method for controlling an automatic transmission having several gears in which a downshift to a lower gear is triggered when, during an actuation of the acceleration pedal toward an increase of the load input, a shifting characteristic line is exceeded. It is proposed to compare an accelerator pedal gradient signal (DKIG) with a presettable threshold value (DKIG_Limit) and to trigger a downshift already before the shifting characteristic line is exceeded when the actual value of the accelerator pedal gradient signal is great than the threshold value. This significantly reduces the reaction time of the transmission.

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Kressbronn, Germany

Adolf Bucher