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| Issue 1298-1 |
| US 6,939,267 B2 |
| Method for controlling gear definition in an automated stepped gearbox |
| Bernd Döbele, Salem (Germany); and Norbert Wiencek, Hagnau (Germany) |
| Assigned to ZF Friedrichshafen AG, Friedrichshafen (Germany) |
| Appl. No. 10/481,094 PCT Filed Jun. 29, 2002, PCT No. PCT/EP02/07200 § 371(c)(1), (2), (4) Date Dec. 17, 2003, PCT Pub. No. WO03/004300, PCT Pub. Date Jan. 16, 2003. |
| Claims priority of application No. 101 32 738 (DE), filed on Jul. 05, 2001. |
| Prior Publication US 2004/0192497 A1, Sep. 30, 2004 |
| Int. Cl.7F16H 59/48 |
| U.S. Cl. 477—120 [477/174; 701/53; 701/67] | 2 Claims |
| 1. A method for controlling a gear release in an automated multi-speed drive in a vehicle drive having a drive motor and a
separating clutch, that is positioned between the drive motor and separating clutch and that can be optionally opened or closed
by a clutch plate whereby a torque of the drive motor is reduced at a start of a shifting process so that shift elements to
be decoupled during the gear release can be decoupled by an actuator with little shift power and the torque of the drive motor
is not increased involuntarily by engaging the clutch, comprising the steps of:
continuously determining a current vehicle acceleration (aveh);
determining a current initial vehicle acceleration (astart) at the start of the shifting process;
determining a first and second vehicle acceleration value (agear—release, aclutch—engage), dependent on the initial vehicle acceleration (astart), a fuel injection quantity EM supplied to the drive motor and the selected actual gear;
constantly comparing the current vehicle acceleration (aveh) with the first and the second vehicle acceleration values (agear—release, aclutch—engage);
applying a shift force from the actuator on the shift elements to be decoupled when the current vehicle acceleration (aveh) reaches the first acceleration value (agear—release) or drops below it; and
opening the clutch with the clutch plate when the current vehicle acceleration value (aveh) reaches or drops below the second vehicle acceleration value (aclutch—engage) whereby at the latest the actuator applies a shift power to the shift elements to be decoupled.
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