Volkswagenwerk Aktiengesellschaft

Volkswagen Ag

Dieter Schmidt

Ernst-August Honig

Gerd Oberpichler

Heinz Dorpmund

Ferdinand Piech

Lothar Kaspar

Manfred Kalversberg

Gottfried Hagemann

In a hydrodynamic-mechanical transmission for motor vehicles, consisting of a torque converter followed by a planetary gear with hydraulically actuable shift mechanism associated with the several transmission elements to select the various speeds, the planetary gear including a first sun gear connectable by way of a first clutch to the turbine rotor of the torque converter, a second sun gear connectable by way of a second clutch to the turbine rotor, a planetary mount connectable by way of a third clutch, bypassing the torque converter, directly to the engine drive shaft, on which mount first and second planet gears in engagement with each other and with the sun gears are mounted, and an internal gear constituting the drive output and in engagement with second planet gears meshing with the second sun gear, the possibility exists of reaching the third, direct speed either by purely hydrodynamic means including the torque converter by engaging the first and second clutches, by purely mechanical means bypassing the torque converter by engaging all three clutches, or in branched power trains by engaging the first or the second clutch and the third clutch. To achieve smooth transitions to and from third speed, when shifting up automatically from second to third speed, first the hydrodynamic train with first and second clutches engaged is to be selectable, and then the mechanical train by additionally engaging the third clutch. Then, shortly before shifting to fourth speed, the branched power train is to be selectable briefly by disengaging the first or the second clutch.

Shifting method for hydrodynamic-mechanical transmission

A control system for a hydrodynamic-mechanical transmission of the type having a by-pass clutch to by-pass the hydrodynamic torque converter includes a main control valve to disengage the forward gear clutch element and thereby the engine from the driving wheels when the accelerator pedal is released. At the same time, the main control valves causes the by-pass clutch, if engaged, to disengage. When the accelerator pedal is depressed, the forward gear clutch element re-engages as well as the by-pass clutch, but since the by-pass clutch is still disengaged at the time the forward gear clutch element re-engages, the jerking motion that may otherwise occur is absorbed in the hydrodynamic torque converter.

Control system for an automobile drive

A pneumatic control system is disclosed for an automatic transmission for a vehicle of the type having a mechanical planetary gear train with hydraulically actuatable gear elements. A manual control valve dependent upon the position of the transmission gear select lever conveys a pressure medium, for actuating a gear shift element associated with the selected gear when said lever is moved to one of the forward gears of the transmission, through a pressure medium line connected between the manual control valve and the gear shift element. The control system comprises a main control valve dependent upon the position of the accelerator pedal for exhausting the fluid in the gear shift element for disengaging the gear shift element in operating states of the vehicle at least when the vehicle is stationary, the transmission gear select lever is moved to the drive position (D), and the accelerator pedal is released.

Pneumatic control system for an automatic vehicle transmission

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Gifhorn, Germany

Dieter Schmidt