Robert Boschgmbh

Joseph Sauer

Alfred Muller

Manfred Schwab

Achim Schreiber

Gerhard Will

Helmut Mohl

Meinrad Feder

Volker Kadelbach

Heinz Leiber

Gerhard Eschrich

Armin Czinczel

Manfred Schab

Method and apparatus for control of gear changing under load in a

To control transmission ratio of a continuously variable transmission connected to a combustion engine (e.g., for optimal fuel efficiency of a powered vehicle), effective diameter of pulleys is controlled in response to an electrical signal. A control signal suitable for comparison with hydrostatic pressure values is produced by a computing device based on input signals representing load, speed, and other operating conditions and based further on stored data representing engine characteristics. A control signal is conveniently used to control hydrostatic pressure by means of electromagnetically operated valves. Especially when pulsed valves controlled by digital electric signals are used, a reservoir is used to establish a steady hydrostatic pressure. Such control device is readily adapted to different engines by replacement of stored characteristic data.

Electronic control for a stepless vehicle transmission using a control

The hydraulic regulating device for an automatic transmission having a selector valve for selecting a plurality of gear stages, includes a high pressure conduit, a working pressure conduit and a shift pressure conduit, a plurality of coupling elements assigned to respective gears, a single, pressure regulating valve electromagnetically controlled by a control signal to build up or decrease pressure in the shift pressure conduit, holding valves connected between the working pressure conduit and the shift pressure conduit, and shift control valves connected to the shift pressure conduit and cooperating with the holding valves to connect, in response to an increased gear, the coupling elements pertaining to the higher gear in a preselected gear stage, to the shift pressure conduit and, upon completion of the gear shift operation, to connect via the working pressure conduit the coupling elements to the high pressure conduit with the exception of the last actuated coupling element who remains connected to the shift pressure conduit.

Hydraulic regulating device for load operated gear shift systems

The hydraulic regulating device for an automatic transmission system in motor vehicles having a plurality of hydraulic couplings, includes a single pressure build-up regulating valve and a single pressure decrease regulating valve and assigned to each coupling a solenoid operated directional control valve having its working port connected to the couplings, its pressure port connected via a switch-on reversing valve to the pressure build-up regulating valve, and its return port connected via a switch-off reversing valve to a return conduit; both reversing valves are controlled according to predetermined pressure levels on the coupling so that in the working position of the switch-on reversing valve the coupling is connected to a stable high pressure and when the coupling process is initiated by reversing the position of the directional control valve, the switch-off reversing valve connects the coupling element to the pressure decrease regulating valve.

Hydraulic regulating device for load shifted gears

To control transmission ratio of a continuously variable transmission connected to a combustion engine (e.g., for optimal fuel efficiency of a powered vehicle), effective diameter of pulleys is controlled in response to an electrical signal. A control signal suitable for comparison with hydrodynamic pressure values is produced by a computing device based on input signals representing load, speed, and other operating conditions and based further on stored data representing engine characteristics. A control signal is conveniently used to control hydrodynamic pressure by means of electromagnetically operated valves. Such control device is readily adapted to different engines by replacement of stored characteristic data.

In first gear, a brake band prevents one gear of the planetary gearing of an automatic transmission from rotating. In second gear, a clutch causes this gear to rotate as a unit with the drive and driven shaft of the transmission. For an upshift under load, the clutch is engaged slowly, thereby decreasing the required brake torque. The brake force is therefore decreased at a corresponding rate. A switch having a movable contact is mounted so that the contact is moved in response to the reactive force created between the brake band and the gear box. This reactive force varies as a function of the brake force and also depends upon the direction of movement of the braked member. The switch is set to a threshold value which is substantially less than the brake force applied in first gear. At the freewheel point, that is the point at which the moment of the brake member changes direction, the brake force has been decreased sufficiently that the change in direction of the moment will cause the switch to pass the threshold value thereby generating a signal. This signal is processed to cause full disengagement of the brake. The switch will also pass the threshold value when, after complete disengagement of the brake, a change in direction of moment of the member occurs. At this point the brake is fully engaged in a downshift under load.

Gearshift method and apparatus

The invention pertains to a hydraulic control system for servos in automatic transmissions, which, in a known fashion, utilizes a main pressure valve to regulate the pressure within the control system and further utilizes a converter pressure valve to supply a hydrodynamic torque converter and the lubrication system. The servos (for example, the clutches) utilized in this type of automatic transmissions cooperate with electromagnetically actuated pressure regulating valves have a current-proportional response. These electromagnetic valves are actuated by electronic control signals generated by sensors which monitor various parameters during operation, making previously utilized sensors superfluous. By control of the pressure regulating valves the forward gear, the reverse gear or the neutral gear can be engaged in the simplest fashion. By means of a magnet valve associated with the main pressure valve the levels of pressure may be varied. It is also possible, via simple associated elements, to install an emergency system which during a failure of the electrical system allows the transmission to continue to operate.

Hydraulic control system for servos in automatic transmissions

For automotive vehicles having an engine which has a speed governor which is activated when the engine reaches the maximum permissible engine speed, an AND-gate is supplied which furnishes an upshift signal when the engine speed has reached the maximum permissible speed and when, simultaneously, the pedal is at the full load position or the kickdown switch is activated. The upshift signal is applied to the control circuit for the automatic transmission. It may be combined with a signal signifying vehicle speed in a direction so as to increase the apparent vehicle speed or with a signal indicative of throttle position to indicate an actual lower engine load than present.

Method and system for upshifting an automatic transmission

To permit placing an electrical-hydraulical controlled automatic transmission, selectively, in reverse or neutral position upon failure of the control or command system, a spool valve is interposed between a fluid pressure pump and the control unit, the spool valve having three positions in which it can be placed manually; one of the positions is its normal operating position in which the valve provides a straight fluid path for pressurized fluid from the pump to the control unit; the other two positions are operable under emergency conditions, a second position providing a connection directly from the valve to the hydraulic servo units associated with control of the reverse gear, and the third interrupting suppply of hydraulic fluid from the pump to the control unit so that the control unit will, effectively, be placed in neutral position.

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Schwieberdingen, Germany

Joseph Sauer