METHOD FOR CARRYING OUT A LOAD SHIFT IN VEHICLES WITH ELECTRIC DRIVE

• US 20100197452A1
• Filed: 08/08/2008
• Published: 08/05/2010
• Est. Priority Date: 08/16/2007
• Status: Active Grant

• Current Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: ZF Friedrichshafen AG (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Wallner, Stefan, Kaltenbach, Johannes
• Granted Patent: US 8,272,993 B2
• Time in Patent Office: Days
• US Class Current: 477/14
• 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

1-8. -8. (canceled)

9. 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 step of:

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

10. The method of carrying out a load shift according to claim 9, the method further comprising the step of adapting the speed of the electric machine (2) such that the speed (n_EM) of the electric machine (2) approaches a target speed (n_Gang_neu) with a low gradient.

11. The method of carrying out a load shift according to claim 9, 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).

12. The method of carrying out a load shift according to claim 9, 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 a torque-controlled mode and completely engaging a shift element (K_neu) being engaged.

13. The method of carrying out a load shift according to claim 9, the method further comprising the step of increasing, in a traction upshift, a transmission capacity of a clutch (K_neu) to be engaged to assume the load;

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

changing the electric machine (2) to a speed regulation mode, when the load has been assumed by the 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 clutch (K_alt) being disengaged.

14. The method of carrying out a load shift according to claim 9, 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 a torque-controlled mode to a 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.

15. The method of carrying out a load shift according to claim 9, 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 a torque-controlled mode to a 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.

16. The method of carrying out a load shift according to claim 9, 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 a torque-controlled mode to a 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.