METHOD AND SYSTEM TO MANAGE DRIVELINE OSCILLATIONS WITH MOTOR TORQUE ADJUSTMENT

• US 20130297109A1
• Filed: 09/13/2012
• Published: 11/07/2013
• Est. Priority Date: 05/07/2012
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Nefcy, Bernard D., Kraska, Marvin Paul, Colvin, Daniel Scott, Lear, Christopher Alan
• Granted Patent: US 9,457,787 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60L 2240/421 Speed
• CPC Class Codes: B60L 2240/423 Torque
• CPC Class Codes: B60L 2240/441 Speed
• CPC Class Codes: B60L 2240/443 Torque
• CPC Class Codes: B60L 2240/507 Operating parameters
• CPC Class Codes: B60L 2240/80 Time limits
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 7/12 for vehicles propelled by dc motors
• CPC Class Codes: B60W 10/02 including control of driveline clutches
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• 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 2050/0056 Low-pass filters
• CPC Class Codes: B60W 2710/023 Clutch engagement rate
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 30/18127 Regenerative braking
• CPC Class Codes: B60W 30/20 Reducing vibrations in the driveline
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

A system and method for controlling a vehicle having an electric traction motor coupled to a transmission by a clutch include modifying traction motor torque in response to the difference between rotational speed of a driveline component and the filtered rotational speed of the driveline component to reduce driveline oscillation when the clutch is locked. The traction motor torque may be modified in response to a vehicle event that may otherwise induce driveline oscillations, such as a transmission ratio change or regenerative braking, for example.

Claims

1. A method for controlling a vehicle having a traction motor coupled to a driveline, comprising:

modifying traction motor torque in response to a difference between a rotational speed of a driveline component and a filtered rotational speed of the driveline component to reduce driveline oscillations.

2. The method of claim 1 wherein the traction motor is selectively coupled to vehicle traction wheels by a clutch disposed therebetween and wherein modifying the traction motor torque is performed only when the clutch is locked.

3. The method of claim 1 wherein the driveline component comprises a traction motor output shaft.

4. The method of claim 1 further comprising:

filtering the rotational speed of the driveline component using a first low-pass filter having a cutoff frequency that varies as a function of the rotational speed of the driveline component.

5. The method of claim 4 further comprising:

filtering the rotational speed of the driveline component using a second low-pass filter having a fixed calibratable cutoff frequency higher than the cutoff frequency of the first low-pass filter.

6. The method of claim 5 wherein modifying the traction motor torque includes integrating the difference between the rotational speed and the filtered rotational speed, the method further comprising:

modifying the traction motor torque in response to a difference between output of the second low-pass filter and the integrated difference between the rotational speed and the filtered rotational speed.

7. The method of claim 1 wherein the vehicle includes a transmission and wherein modifying the traction motor torque comprises modifying the fraction motor torque in response to a ratio change of the transmission.

8. The method of claim 1 wherein modifying the traction motor torque comprises modifying the traction motor torque in response to activation of a vehicle regenerative braking system.

9. A system for controlling a powertrain of a vehicle, comprising:

a fraction motor for powering wheels of the vehicle; and

a controller in communication with the traction motor, the controller configured to modify traction motor torque in response to a difference between a rotational speed of a driveline component and a filtered rotational speed of the driveline component to reduce driveline oscillations.

10. The system of claim 9 further comprising a clutch disposed between the traction motor and the wheels of the vehicle, wherein the controller modifies the traction motor torque when the clutch is locked.

11. The system of claim 9 further comprising a clutch disposed between the traction motor and the wheels of the vehicle, wherein the controller modifies the traction motor torque only when clutch slip is below a corresponding threshold.

12. The system of claim 9 wherein the controller filters the rotational speed of the driveline component using a first low-pass filter having a cutoff frequency that varies as a function of the rotational speed of the driveline component.

13. The system of claim 12 wherein the controller filters the rotational speed of the driveline component using a second low-pass filter having a cutoff frequency higher than the cutoff frequency of the first low-pass filter.

14. The system of claim 9 further comprising:

a multiple ratio transmission disposed between the traction motor and vehicle traction wheels;

a first clutch selectively coupling an internal combustion engine to the traction motor; and

a second clutch selectively coupling the traction motor to the transmission.

15. The system of claim 14 wherein the controller modifies the traction motor torque in response to a ratio change of the transmission.

16. The system of claim 9 further comprising a regenerative braking system, wherein the controller modifies the traction motor torque in response to activation of the regenerative braking system.

17. A hybrid electric vehicle, comprising:

an engine;

a fraction motor selectively coupled to the engine by a first clutch;

a fraction battery electrically connected to the traction motor;

a transmission selectively coupled to the traction motor by a second clutch; and

a controller in communication with the traction motor, the engine, and the transmission, the controller configured to modify traction motor torque when the second clutch is locked in response to a difference between a rotational speed of a driveline component and a filtered rotational speed of the driveline component.

18. The vehicle of claim 17 wherein the second clutch is disposed within the transmission.

19. The vehicle of claim 17 wherein the driveline component comprises an output shaft of the traction motor.

20. The vehicle of claim 17 wherein the controller comprises:

a first low-pass filter having a cutoff frequency that varies as a function of the rotational speed of the driveline component; and

a second low-pass filter having a cutoff frequency higher than the cutoff frequency of the first low-pass filter.