Method for carrying out a load shift in vehicles with electric drive

• US 8,272,993 B2
• Filed: 08/08/2008
• Issued: 09/25/2012
• Est. Priority Date: 08/16/2007
• Status: Expired due to Fees

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Kaltenbach, Johannes, Wallner, Stefan
• Primary Examiner(s): YOUNG, EDWIN
• Application Number:
  US12/671,130
• Publication Number:
  US 20100197452A1
• Time in Patent Office: 1,509 Days
• Field of Search: 477/8, 477/20, 477/109, 477/111
• US Class Current: 477/8
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/40 Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers power-up or power-down of the driveline B60W30/192
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 2061/0422 by an electric machine, e.g. by accelerating or braking the input shaft
• CPC Class Codes: F16H 61/0403 Synchronisation before shifting
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

A method of carrying out a shift under load in either an electric vehicle which has a change-under-load transmission or a hybrid vehicle which has a hybrid transmission while the vehicle is operating in a purely electrical mode. The speed adaptation of the electric machine, which is required for synchronization to a new gear, is carried out in a speed regulation mode.

Claims

1. A method of carrying out a shift under load in either an electric vehicle having a change-under-load transmission or a hybrid vehicle having a hybrid transmission during purely electric driving operation, the method comprising the steps of:

employing an electric machine being operatable in both a speed control mode and a torque regulation mode;

carrying out a shift under load in the transmission during a purely electric driving operation by operating the electric machine in the torque-controlled mode; and

adapting a speed of the electric machine (2), required for synchronization to a new gear, with the electric machine operating in the speed regulation mode.

2. The method of carrying out a load shift according to claim 1, the method further comprising the step of adapting the speed of the electric machine (2) such that a slope of the speed of the electric machine (2) (n_EM), with respect to time, comprising the time the electric machine (2) changes from a speed associated with an old gear (n_Gang_alt) to a target speed associated with a new gear (n_Gang_neu), forms a sigmoidal curve.

3. The method of carrying out a load shift according to claim 2, the method further comprising the step of forming the sigmoidal curve to be substantially shaped as an ogee curve.

4. The method of carrying out a load shift according to claim 1, the method further comprising the step of utilizing torque (K_alt, K_neu) of shift elements, acting on the electric machine (2), as pilot control means for the speed adaptation of the electric machine (2).

5. The method of carrying out a load shift according to claim 1, the method further comprising the step of, when the speed (n_EM) of the electric machine (2) reaches either a target speed or a synchronous speed (n_Gang_neu) of a gear to be engaged, returning the electric machine (2) to the torque-controlled mode and completely engaging a shift element (K_neu) being engaged.

6. The method of carrying out a load shift according to claim 1, the method further comprising the step of increasing, in a traction upshift, a transmission capacity of a new clutch (K_neu) to be engaged to assume the load;

simultaneously reducing a transmission capacity of an engaged clutch (K_alt) to be disengaged,

changing the electric machine (2) to the speed regulation mode, when the load has been assumed by the new clutch (K_neu) being engaged; and

adapting the speed of the electric machine (2) to a synchronous speed of a gear to be engaged such that, in the speed regulation mode, the electric machine (2) is adjusted to either a target speed or a synchronous speed of the gear to be engaged and simultaneously completely disengaging the engaged clutch (K_alt) being disengaged.

7. The method of carrying out a load shift according to claim 1, the method further comprising the step of:

reducing, in a traction downshift, a transmission capacity of a shift element (K_alt) to be disengaged;

changing the electric machine (2) from the torque-controlled mode to the speed regulation mode as soon as slip is detected in the shift element (K_alt) being disengaged;

increasing the speed of the electric machine (2), in the speed regulation mode, to a speed higher than a synchronous speed of a shift element (K_neu) to be engaged;

increasing a transmission capacity of the shift element (K_neu) to be engaged and further reducing the transmission capacity of the shift element (K_alt) being disengaged, such that uptake of the load by the shift element (K_neu) being engaged is continuous; and

completely disengaging the shift element (K_alt) being disengaged on completion of the load uptake by the shift element (K_neu) being engaged and adjusting the speed of the electric machine (2) to the synchronous speed of the shift element (K_neu) being engaged.

8. The method of carrying out a load shift according to claim 1, the method further comprising the step of:

essentially simultaneously increasing, in a thrust downshift, a transmission capacity of a shift element (K_neu) to be engaged and reducing a transmission capacity of a shift element (K_alt) to be disengaged;

changing the electric machine (2) from the torque-controlled mode to the speed regulation mode, after a load is assumed by the shift element (K_neu) being engaged;

substantially disengaging the shift element (K_alt) being disengaged; and

adjusting a speed of the electric machine (2), in the speed regulation mode, to a synchronous speed and essentially simultaneously completely disengaging the shift element (K_alt) being disengaged.

9. The method of carrying out a load shift according to claim 1, the method further comprising the step of:

continuously reducing, in a thrust upshift, a transmission capacity of a shift element (K_alt) to be disengaged;

changing the electric machine (2) from the torque-controlled mode to the speed regulation mode, when slip is detected at the shift element (K_alt) being disengaged, and reducing the speed of the electric machine (2) to a value lower than a synchronous speed of the shift element (K_neu) to be engaged;

increasing a transmission capacity of the shift element (K_neu) to be engaged and reducing the transmission capacity of the shift element (K_alt) being disengaged such that uptake of the load by the shift element (K_neu) being engaged is continuous; and

completely disengaging the shift element (K_alt) being disengaged on completion of the load uptake by the shift element (K_neu) being engaged and adjusting the speed of the electric machine (2), in the speed regulation mode, to the synchronous speed of the shift element (K_neu) being engaged.

10. A method of carrying out a shift under load in either an electric vehicle having a change-under-load transmission or a hybrid vehicle having a hybrid transmission during purely an electric driving operation in which the vehicle comprises an electric machine and an internal combustion engine with a drive train clutch located between the electric machine and the internal combustion engine, the method comprising the steps of:

employing an electric machine being operatable in both a speed control mode and a torque regulation mode;

disengaging the drive train clutch located between the electric machine and the internal combustion engine, during a shift, so as to provide purely an electric driving operation and operating the electric machine in the torque-controlled mode;

carrying out a shift under load in the transmission during the purely electric driving operation;

changing the electric machine from the torque-controlled mode to a speed regulation mode once the transmission load of the vehicle is taken up by a new clutch to be engaged; and

adapting a speed of the electric machine, required for synchronization to a new gear, with the electric machine operating during the speed regulation mode.

11. The method of carrying out a load shift according to claim 10, the method further comprising the step of adapting the speed of the electric machine such that a slope of the speed of the electric machine, with respect to time, changes from a speed associated with an old gear (n_Gang_alt) to a target speed associated with a new gear (n_Gang_neu), forms a sigmoidal curve.

12. The method of carrying out a load shift according to claim 10, the method further comprising the step of utilizing torque (K_alt, K_neu) of shift elements, acting on the electric machine, as pilot control means for the speed adaptation of the electric machine.

13. The method of carrying out a load shift according to claim 10, the method further comprising the step of, when the speed of the electric machine reaches either a target speed or a synchronous speed (n_Gang_neu) of a gear to be engaged, returning the electric machine (2) to the torque-controlled mode and completely engaging a shift element (K_neu) to be engaged.

14. The method of carrying out a load shift according to claim 10, the method further comprising the step of increasing, in a traction upshift, a transmission capacity of the new clutch (K_neu) to be engaged to assume the load;

simultaneously reducing a transmission capacity of an engaged clutch (K_alt) to be disengaged,

changing the electric machine (2) to the speed regulation mode, when the load has been assumed by the new clutch (K_neu) to be engaged; and

adapting the speed of the electric machine (2) to a synchronous speed of a gear to be engaged such that, in the speed regulation mode, the electric machine (2) is adjusted to either a target speed or a synchronous speed of the gear to be engaged and simultaneously completely disengaging the engaged clutch (K_alt) to be disengaged.

15. The method of carrying out a load shift according to claim 10, the method further comprising the step of:

reducing, in a traction downshift, a transmission capacity of a shift element (K_alt) to be disengaged;

changing the electric machine from the torque-controlled mode to the speed regulation mode as soon as slip is detected in the shift element (K_alt) to be disengaged;

increasing the speed of the electric machine, in the speed regulation mode, to a speed higher than a synchronous speed of a shift element (K_neu) to be engaged;

increasing a transmission capacity of the shift element (K_neu) to be engaged and further reducing the transmission capacity of the shift element (K_alt) to be disengaged, such that uptake of the load by the shift element (K_neu) to be engaged is continuous; and

completely disengaging the shift element (K_alt) to be disengaged on completion of the load uptake by the shift element (K_neu) to be engaged and adjusting the speed of the electric machine (2) to the synchronous speed of the shift element (K_neu) to be engaged.

16. The method of carrying out a load shift according to claim 10, the method further comprising the step of:

simultaneously increasing, in a thrust downshift, a transmission capacity of a shift element (K_neu) to be engaged and reducing a transmission capacity of a shift element (K_alt) to be disengaged;

changing the electric machine (2) from the torque-controlled mode to the speed regulation mode, after a load is assumed by the shift element (K_neu) to be engaged;

substantially disengaging the shift element (K_alt) to be disengaged; and

adjusting a speed of the electric machine (2), in the speed regulation mode, to a synchronous speed and essentially simultaneously completely disengaging the shift element (K_alt) to be disengaged.

17. The method of carrying out a load shift according to claim 10, the method further comprising the step of:

continuously reducing, in a thrust upshift, a transmission capacity of a shift element (K_alt) to be disengaged;

changing the electric machine (2) from the torque-controlled mode to the speed regulation mode, when slip is detected at the shift element (K_alt) to be disengaged, and reducing the speed of the electric machine (2) to a value lower than a synchronous speed of the shift element (K_neu) to be engaged;

increasing a transmission capacity of the shift element (K_neu) to be engaged and reducing the transmission capacity of the shift element (K_alt) being disengaged such that uptake of the load by the shift element (K_neu) to be engaged is continuous; and

completely disengaging the shift element (K_alt) to be disengaged on completion of the load uptake by the shift element (K_neu) to be engaged and adjusting the speed of the electric machine (2), in the speed regulation mode, to the synchronous speed of the shift element (K_neu) to be engaged.

18. A method of carrying out a shift under load in either an electric vehicle having a change-under-load transmission or a hybrid vehicle having a hybrid transmission during purely an electric driving operation in which the vehicle comprises an electric machine and an internal combustion engine with a drive train clutch located between the electric machine and the internal combustion engine, the method comprising the steps of:

employing an electric machine which is operatable in both a speed control mode and a torque regulation mode;

disengaging the drive train clutch located between the electric machine and the internal combustion engine, during a shift, so as to provide purely an electric driving operation and operating the electric machine in the torque-controlled mode;

carrying out a shift under load in the transmission during the purely electric driving operation by increasing a transmission capacity of a new clutch to be engaged, in order to take up a transmission load of the vehicle, and, at the same time, reducing a transmission capacity of an engaged clutch to be disengaged;

changing the electric machine from the torque-controlled mode to a speed regulation mode once the transmission load of the vehicle is taken up by the new clutch to be engaged; and

adapting a speed of the electric machine, required for synchronization to a new gear, with the electric machine operating during the speed regulation mode and simultaneously completely disengaging the engaged clutch (K_alt) to be disengaged.