Dr. Ing. H.c. F. Porsche Aktiengesellschaft

Robert Boschgmbh

Zahnradfabrik Friedrichshafen, Ag.

Joseph Petersmann

Willi Seidel

Heinz Stehle

Patric Lardy

Werner Mollers

Gerhard Eschrich

Wolfgang Runge

Wolf-Dieter Gruhle

Peter Wendel

Thomas Wehr

Ronald Schwamm

Thomas Foeldi

Uwe Froschke

Ludwig Hamm

Udo Hickmann

Patrick Lardy

Udo Judaschke

The invention relates to a method for controlling a continuously variable transmission with an electrohydraulic control, a selector device, and a controllable engaging clutch of a motor vehicle, especially one powered by an internal combustion engine, with a control device in a first operating mode automatically selecting and adjusting a gear ratio for the transmission from signals of the selector device and the operating parameters of the motor vehicle such as the throttle angle, driving speed and engine rpm, by means of curves selectable by the driver. It is proposed, in a second operating mode, to simulate a multi-step transmission influenceable directly by the driver. In order to permit use of this operating mode, only a few preset gear ratios are made available to the driver. In addition, from the operating parameters of the vehicle, but at least from a throttle signal value, as described in DE-OS 39 22 051, a parameter called driving activity SK(t) is obtained which evaluates the driving style of the driver or his behavior as a function of traffic situations relative to the control of the motor vehicle. The preset gear ratios are combined in groups. Depending on the driving activity SK(t) which has been determined, a group is selected. With higher driving activity SK(t), groups are selected in which the gear ratios are spread more widely and the number of gear ratios is greater. For less driving activity, SK(t) groups are selected whose spread is less and in which the number of gear ratios is smaller.

Method of controlling a continuously variable transmission automatically

The invention provides a method and apparatus for controlling a continuously variable speed transmission of a motor vehicle driven by an internal-combustion engine, by means of a control arrangement having a selecting device which simulates a stepped transmission by adjusting transmission ratios in according to a group of preset transmission ratios. To prevent repeated up and down shifting, a control arrangement is provided with a unit for detecting driving situations in which a transmission ratio shift according to the preset transmission rations would be too large, and also a unit for adjusting the preset transmission ratio. The recognition unit activates the adjustment unit as soon as the above-described driving situation occurs, and the adjustment unit then changes a preset transmission ratio so that the motive force is adapted to the present motive resistance, allowing the vehicle to achieve a positive longitudinal acceleration.

Process and apparatus for controlling a continuously variable speed

A control system and process for an infinitely variable transmission which has a first operating mode which automatically selects the transmission ratio, and a second operating mode in which the transmission ratio can be selected directly by the driver. According to the invention, the degree of damping effective during the adjustment of the transmission ratio is adjusted in response to the selected operating mode. In the automatic operating mode, a high degree of damping is used, while in the manual operating mode, a lower degree of damping is provided.

Control system and control process for an infinitely variable

The invention relates to a process for controlling a change of the transmission ratio (ue) in an infinitely variable transmission, which simulates a stepped transmission. A basic shifting time is determined separately for each shifting position and direction. In addition, a rotational speed factor, is used to take into account the change of the rotational input speed of the transmission caused by the change of the transmission ratio, and a lead factor reflects the lead existing at the transmission input. Shifting of the infinitely variable transmission is then performed as a function of the basic shifting time, the rotational speed factor and the lead factor.

Process for determining the shifting time for a transmission ratio

A CVT is operated in both a continuously-variable mode and in a simulated stepped-ratio mode. In the stepped ratio mode, the highest preset transmission ratio (e.g., 'first gear'), is variable and responsive to vehicle driving conditions. A control senses a low vehicle speed operating condition and adapts the highest ratio to reduce the step up to the next preset ratio. The control also senses a vehicle start condition and adapts the highest ratio to the current engine torque to improve drivability.

Control device and control process for an infinitely variable

Method for controlling kickdown while braking and as a function of

Method for control of an automatic transmission of a motor vehicle

This invention provides a method and apparatus for controlling a continuously variable speed transmission connected with an internal-combustion engine according to one or several characteristic control curves. A transmission ratio of the transmission is automatically set according to the position of a power control element. In order to be able to operate the internal-combustion at its consumption-optimal point, a 'constant driving method' which requires only a low reserve of tractive force is detected, and transmission ratio is adjusted in response thereto, so that the internal-combustion engine is operated in its point of the lowest specific fuel consumption for the existing operating point of the vehicle.

Control process and control arrangement for a continuously variable

Method for controlling a continuously variable transmission of a motor

Method for controlling an infinitely variable motor vehicle transmission

Method for controlling an automatically operated motor vehicle

Method for automatic control of an RPM-changing engaging device of a

A process is described for controlling the actuating pressure in a control element (shift element) of an electrohydraulically controlled transmission of a motor vehicle during a change of the gear position. In the case of downshifts in the coasting operation, the hydraulic pressure in the transmission is preferably increased with the initiating of the shifting by way of the pressure control valve in a time-limited manner. Starting from a presettable or preset basic value, the amount of this filling pulse is automatically and in steps for each control operation in the course of the operation of the transmission adapted to a target value in such a manner that an input rotational speed of the transmission or a rotational speed of a driving engine connected in front of the transmission follows a predetermined sequence of movements.

Process for controlling the actuating pressure in a control element of

The invention relates to an electrohydraulic control for an automatic transmission of a motor vehicle. In order to be able to utilize, in the coasting operation of the motor vehicle in the driving position D of the automatic transmission, also the first gear, a one-way clutch, which transmits only driving torques but is required for the shifting operation, when the first gear is engaged, is bridged by a brake so that the transmission can transmit not only driving but also coasting torques and can therefore transmit the engine braking torque.

Electrohydraulic control for an automatic transmission

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Wimsheim, Germany

Joseph Petersmann