Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Transmission control
Reexamination Certificate
1999-08-04
2001-05-22
Louis-Jacques, Jacques H. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Transmission control
C701S051000, C701S054000, C701S058000, C477S107000, C477S110000
Reexamination Certificate
active
06236925
ABSTRACT:
The invention relates to a method for increasing the driving comfort of motor vehicles, especially in load reversal operations, by controlling the dynamics of the driver's desired torque.
In motor vehicles having automatic transmission, there appear in certain situations, such as in positive and negative load reversals, jolts that impair the comfort. To prevent such jolts during the gear shifting operation of the automatic transmission, it has already been proposed in DE-C 29 35 916 that the torque of the internal combustion engine is reduced during the gear shift. Together with the reduction of the jolts when shifting, it is possible by the reduced torque of the internal combustion engine during the gear shift, also to reduce the slip time of the friction clutches of the automatic transmission that take part in the gear shift so that less heating and less wear of the friction elements occur. The control electronics for the internal combustion engine is equipped with a recognition control system which receives a switch signal from the transmission control during the gear shift. In a memory of the control device for the internal combustion engine, characteristic fields are deposited according to which the firing angle and/or the injection pulse width are controlled, depending on load and rotational speed. If a switch signal is fed to the recognition control system of the control electronics of the internal combustion engine, the control device shifts automatically to another characteristic field in which, by adjusting the firing angle in “late” direction or reduction of the injected amount of fuel, the torque of the internal combustion engine is reduced.
The exact determination of the moment of reduction of the torque already poses problems. Besides, such storing of different characteristic fields and a change of characteristic fields are relatively expensive.
DE-A 40 37 092 describes a method for control of the torque of an internal combustion engine which is combined with an automatic transmission driven by the internal combustion engine. Associated with the internal combustion engine is a control electronic system which controls the firing angle of the ignition system and/or the injection pulse width of the fuel injection system on the basis of rotational speed, load and, if needed, temperature signals. The transmission electronics associated with the automatic transmission controls for its part switching operations of the automatic transmission on the basis of rotational speed and load request signals.
To improve the control of the whole driving unit for the purpose of achieving jolt-free gear shifts, computer systems of the transmission control electronics and of the electronics of the internal combustion engine are steadily in communication with each other via interfaces wherein the control electronics of the internal combustion engine is fed from the transmission electronics in a cycle time beat and a percentage torque request on the basis of which the control device automatically controls the torque of the internal combustion engine.
A central microprocessor system is used for said purpose in which the individual microprocessors of the control electronics of the internal combustion engine and of the transmission electronics exchange data via serial or parallel interfaces. Via the interfaces, the actual data of the transmission electronics and corresponding requests are continually relayed to the control electronics for the internal combustion engine, which for its part can be thereby adapted to the transmission electronics. Thereby the transmission electronics can, at any time, transmit to the control electronics of the internal combustion engine, in the cyclic time, bear a desired reduction or increase with the aid of percent values.
SUMMARY OF THE INVENTION
Another possibility is to associate with the engine electronics so called comfort filters as dampers of load reversal and jolts.
The problem to be solved by the invention is to provide a method by which the dynamics of the driver's desired torque is controlled in a manner such that the comfort can still be further increased.
Departing from a method of the kind above described in detail, the problem is solved with the feature stated in the characteristic part of claim
1
; advantageous developments are described in the subclaims.
For the whole KFZ system, it constitutes a considerable improvement in comfort that the dynamics of the driver's desired torque be controlled in certain situations by the transmission electronics. This is particularly advantageous in jerky accelerator pedal changes, i.e. during positive and negative load reversals. In connection with a CVT transmission, the physically predetermined limits of the flow rate/pressure balance and the hydraulic dead time of the pressure buildup in the contact and ratio adjusting system can be taken into account as needed and harmful variator slip be effectively prevented. In relation to continuously variable automatic transmissions, the comfort, e.g. in gear shift operations where the driver gives gas during the gear shift cycle, can be improved by taking into account as needed the hydraulic cycles during the change of gear.
REFERENCES:
patent: 4507986 (1985-04-01), Okamura et al.
patent: 5364321 (1994-11-01), Togai et al.
patent: 5383824 (1995-01-01), Runge et al.
patent: 5433676 (1995-07-01), Abe et al.
patent: 5722362 (1998-03-01), Takano et al.
patent: 5938712 (1999-08-01), Ibamoto et al.
patent: 29 35 916 C2 (1981-04-01), None
patent: 40 37 092 A1 (1992-05-01), None
patent: 38 30 938 C2 (1992-11-01), None
patent: 29 35 916 C3 (1994-12-01), None
patent: 94/05934 (1994-03-01), None
Gierling Armin
Hengstler Hans-Dieter
Davis & Bujold P.L.L.C.
Louis-Jacques Jacques H.
ZF Friedrichshafen AG
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