Control of a powertrain backlash

Patent metadata

Field	Value
Publication number	US-10634200-B2
Application number	US-201716091367-A
Country	US
Kind code	B2
Filing date	Apr 3, 2017
Priority date	Apr 12, 2016
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

A method and a system for controlling a backlash of a powertrain included in a vehicle in connection with a gear shifting operation is presented. The method comprises: controlling, in connection with a first gear shifting operation, a clutch included in the powertrain to a slipping position, in which slipping position the clutch transfers a slipping torque that is less than a torque being transferred in a closed position for the clutch; analyzing a change of a rotational speed for an input shaft of a gearbox included in the powertrain; determining a position for the clutch, for which position the change of the rotational speed has a value corresponding to a backlash torque, the backlash torque having a predetermined value for eliminating the backlash; and utilizing the determined clutch position for controlling the clutch in connection with a second subsequent gear shifting operation.

First claim

The invention claimed is:

1. A method for controlling a backlash of a powertrain included in a vehicle in connection with a gear shifting operation, said method comprising:
controlling, in connection with a first gear shifting operation, a clutch included in said powertrain to a slipping position, in which slipping position said clutch transfers a slipping torque that is less than a torque being transferred in a closed position for said clutch;
analyzing a change of a rotational speed for an input shaft of a gearbox included in said powertrain;
determining a position for said clutch, for which position said change of said rotational speed has a value corresponding to a backlash torque, said backlash torque having a predetermined value for eliminating said backlash; and
utilizing said determined clutch position for controlling said clutch in connection with a second subsequent gear shifting operation.

2. A method as claimed in claim 1 , wherein said clutch in connection with said second subsequent gear shifting operation is controlled to be in said determined clutch position when said gearbox is changed into a target gear position.

3. A method as claimed in claim 1 , wherein said clutch in connection with said second subsequent gear shifting operation is controlled to be in said determined clutch position after said gearbox has been changed into a target gear position.

4. A method as claimed in claim 2 , wherein said gearbox is changed into said target gear position when said rotational speed for an input shaft is essentially equal to a target value for a rotational speed of an engine included in said powertrain.

5. A method as claimed in claim 2 , wherein said clutch is controlled to be in said determined clutch position at least initially during up-ramping of a powertrain torque after said second gear changing operation.

6. A method as claimed in claim 1 , wherein said controlling of said clutch is preceded by:
shifting said gearbox into a neutral gear position; and
braking said input shaft to a rotational speed value being lower than a target value for a rotational speed of an engine included in said powertrain.

7. A method as claimed in claim 6 , wherein said braking is effected by an input shaft brake arrangement.

8. A method as claimed in claim 1 , wherein said determining of said position for said clutch is followed by verifying said eliminating of said backlash based on an analysis of a difference between said rotational speed for said input shaft and a converted rotational wheel speed, said converted rotational wheel speed being calculated based on a rotational speed of at least one driving wheel and on a total gearing ratio between said input shaft and said at least one driving wheel.

9. A method as claimed in claim 8 , wherein said backlash torque is controlled such that said difference is less than a predetermined value during said eliminating of said backlash.

10. A method as claimed in claim 1 , wherein said position for said clutch corresponds to a position for a clutch actuator controlling a degree of opening for said clutch.

11. A method as claimed in claim 1 , wherein said value for said change in rotational speed is dependent on a rotational inertia of one or more parts of said clutch and said gearbox.

12. A method as claimed in claim 1 , wherein said predetermined value of said backlash torque is within a range of 10-50 Nm.

13. A computer program product comprising computer program code stored on a non-transitory a computer readable medium, said computer program product for controlling a backlash of a powertrain included in a vehicle in connection with a gear shifting operation, said computer program product comprising computer instructions to cause said at least one control unit to perform the following operations:
controlling, in connection with a first gear shifting operation, a clutch included in said powertrain to a slipping position, in which slipping position said clutch transfers a slipping torque that is less than a torque being transferred in a closed position for said clutch;
analyzing a change of a rotational speed for an input shaft of a gearbox included in said powertrain;
determining a position for said clutch, for which position said change of said rotational speed has a value corresponding to a backlash torque, said backlash torque having a predetermined value for eliminating said backlash; and
utilizing said determined clutch position for controlling said clutch in connection with a second subsequent gear shifting operation.

14. A system for controlling a backlash of a powertrain included in a vehicle in connection with a gear shifting operation, said system comprising:
a clutch control unit, arranged for controlling, in connection with a first gear shifting operation, a clutch included in said powertrain to a slipping position, in which slipping position said clutch transfers a slipping torque that is less than a torque being transferred in a closed position for said clutch;
an analysis unit, arranged for analyzing a change of a rotational speed for an input shaft of a gearbox included in said powertrain; and
a determination unit arranged for determining a position for said clutch, for which position said change of said rotational speed has a value corresponding to a backlash torque, said backlash torque having a predetermined value suitable for eliminating said backlash,
wherein said clutch control unit, arranged for utilizing said determined clutch position for controlling said clutch in connection with a second subsequent gear shifting operation.

Assignees

• Scania Cv Ab

Inventors

• Udd Jonas
• Kjell Anders

Classifications

• F16D2500/50239

  Soft clutch engagement · CPC title

• F16D2500/10406

  Clutch position · CPC title

• B60W2510/0266

  Moment of inertia · CPC title

• F16H2061/0411

  by control of shaft brakes · CPC title

• B60W2510/102

  Input speed change rate · CPC title