Robert Boschgmbh

Gerhard Will

Walter Stroh

Joseph Sauer

Volker Kadelbach

Martin Zechnall

In order to diminish the lurching which occurs when automatic transmissions of motor vehicles perform gear changes, the invention describes apparatus for gradual changes of the engine torque at or near the onset of the gear change as well as at or near the time of gear reengagement. The engine torque may be changed by altering the fuel metering characteristics and/or the ignition timing in a gradual and controlled manner.

Torque control for internal combustion engines

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

A comparator circuit compares an engine speed signal with an engine load signal, the latter being furnished to the comparator through transistors controlled by switching signals representative of the condition of the gear range selection lever, the kickdown switch and the magnetic valve that operates, when actuated, to shift from high gear to a lower gear. The circuit is operative only when the kickdown switch is unoperated and the gear range selection lever is in the 'drive' position that permits operation in high gear. The magnetic valve position indication is coupled to the circuit through a differentiating network, so that the circuit comes into play only for a short interval following the switching over of the magnetic valve from the high gear position. If at that time the ratio of engine speed to engine load, instead of being consistent with the automatic transmission shift program, is in the range where a downshift would involve risk to the safety of the vehicle, the circuit operates to cut off the current supply to the magnetic valve, forcing it to return into the high gear condition. Operation of the magnetic valve as the result of a failure of a component in the electronic control of the transmission or some other accidental disturbance is thereby prevented from endangering the vehicle.

Safety circuit for electronically controlled automatic vehicle

The electromagnetically operated sliding spool control valve particularly for use in connection with an automatic transmission system of a motor vehicle, comprises an armature of the electromagnet which is supported at one end of a plunger the other end of which is formed into a sliding spool. The spool is guided in a valve sleeve integrally connected to a fixed core of the electromagnetic coil. A return spring is arranged around a plunger portion between the core and the armature. The valve sleeve is seated in a central boring of a valve channel plate provided with a plurality of annular grooves communicating via transverse borings with the central passage of the sleeve. The sleeve opens into a pressure space which communicates via a flow return channel with a port for the main pressure so that the main pressure acts against the free end of the spool.

Electromagnetically operated control valve

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.

Control system for automotive automatic transmission with emergency

In order to be able to reduce the jolt produced by the transmission going into gear when the vehicle is standing still or moving only slowly, the shifting of the gear range selector lever from neutral gear into any drive range gear is caused to operate magnetic valves controlling the automatic transmission to set the transmission in the highest gear for a very brief period, enough to reduce the jolt, but not enough to interfere with the normal progress of automatic gear shifting.

Method and apparatus for reducing jolt in vehicle automatic transmissions

A pump, driven by the engine, supplies hydraulic pressure as a function of engine speed; the engine controller provides a displacement force, for example by a cam, acting on a main valve slider, or spool of the switching pressure controller. To additionally provide a speed signal to the main spool, the switching pressure line, connected to the pump, has a Venturi, diaphragm, bent tube, or other constriction therein from which a hydraulic signal representative of engine speed can be derived, which hydraulic signal is applied as a force additionally acting on the main valve slider or spool so that the spool position, and hence output switching pressure, will be representative both of engine controller position as well as of engine speed.

Load and speed dependent gear change hydraulic pressure generator

To permit continued operation of an electronically controlled gear change transmission in case of failure of electronic control signals, at least one three-way check valve is included in the system to connect, in one mode of operation, the normal output control signals from a hydraulic control valve system to engage an operating element (such as a control clutch, control band, or the like in the automatic transmission) and, when in another position, connect hydraulic pressure to effect connection of drive power to the first gear, or reverse (as selected by a control selector) and in the absence of electrical command signals from the electronic control unit. By use of a second three-way check valve, simple interlocks to prevent shifting into reverse when the vehicle is moving forward in excess of a given speed, and to permit holding of an engaged gear in case of malfunction, can be provided.

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Steinheim, Germany

Gerhard Will