Robert Boschgmbh

Walter Stroh

Manfred Schwab

Gerhard Will

Alfred Muller

Martin Zechnall

Gerhard Heess

Helmut Mohl

Holger Hofmann

The invention is directed to the automatic determination of a quantity which represents the rpm ratio between the transmission and the wheels. For this purpose, first and second rpm values are first detected which represent the rpm of at least one wheel and the rotational speed of a transmission component. Furthermore, a driving state quantity is formed which represents the instantaneous driving state of the motor vehicle. The essence of the invention is that a pregiven driving state can be determined when the formed driving state quantity indicates an essentially steady state driving state. The determination of the rpm transmission ratio which is sought takes place in dependence upon the detected rpm values when the pregiven operating state is detected. Furthermore, the invention relates to a stepped method which, for example, ensures a rapid determination of the differential transmission ratio after a transmission control apparatus is newly built in.

Method and arrangement for automatically determining the differential gear ratio

The automatic transmission control unit in a motor vehicle furnishes a signal which signifies that motor torque is to be decreased, thereby decreasing jolts or wear on friction elements in the transmission. In response to this signal, the input or output signals of a motor control unit, for example either an ignition control stage or an injection control stage, are changed in such a way that the motor torque will be decreased. Circuits for delaying ignition timing, shortening the pulse width of injection pulses, etc. are disclosed. The present invention is essentially an adapter unit so that the desired decrease in motor torque can be effected with the injection or ignition timing units already present in the motor vehicle.

Apparatus for decreasing jolts during gear shifts in automatic

In previously known jolt control equipment, it was necessary to know the speed of the turbine of a fluid coupling or hydraulic torque converter driving the automatic transmission. According to the present invention, the turbine speed is assumed to be the same as the impeller or motor speed after the torque transmission through the automatic transmission has been interrupted. Under these conditions, very little slippage in the fluid coupling takes place and the turbine speed is equal to the impeller or motor speed to a sufficient accuracy. The synchronous turbine speed which determines when the jolt control is to be initiated and terminated is computed from the transmission output speed multiplied by the speed ratio between turbine and transmission output in the gear to be engaged.

Method and apparatus for computing motor speeds for initiating and

The signal initiating a reduction of engine torque during gear shift is derived from a monitoring of the engine speed. Specifically, the decrease in torque is initiated when engine deceleration, as determined by the negative speed gradient, exceeds a predetermined value. The torque decrease can, as preferred, take place only if a gear shift occurs, or it may take place independent of gear shift in which case high decelerations caused, for example, by rapid application of the brakes, also cause the decrease.

Method and apparatus for controlling the torque of an internal

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

The initiation and end of the application of a jolt control system to the internal combustion engine during gearshift operations is matched to then-present operating conditions by determining the engine speeds at which the control is to be initiated and ended as a function of the engine speed at the start of the gearshifting. For this purpose, the initial speed is digitalized and used as an address for a storage which contains the desired values. In a second embodiment, the speed at the end of the gearshift is determined and the values read out from storage are speed increment values which are added to the speed at the start of the gearshifting and subtracted from the speed at the end of the gearshift during downshift operations, and vice versa during upshift operations, to determine the engine speeds at which the jolt control is to be initiated and terminated.

Apparatus and method for improving the jolt control in a motor vehicle

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

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.

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Cleebronn, Germany

Walter Stroh