NEGATIVE DRIVELINE TORQUE CONTROL INCORPORATING TRANSMISSION STATE SELECTION FOR A HYBRID VEHICLE

• US 20080318728A1
• Filed: 06/20/2007
• Published: 12/25/2008
• Est. Priority Date: 06/20/2007
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Soliman, Ihab, Aswani, Deepak
• Granted Patent: US 7,828,693 B2
• Time in Patent Office: Days
• US Class Current: 477/4
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 2006/4833 Step up or reduction gearing driving generator, e.g. to operate generator in most efficient speed range
• CPC Class Codes: B60K 6/442 Series-parallel switching type
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 2240/425 Temperature
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60W 10/06 including control of combustion engines
• 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 10/184 with wheel brakes
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• 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 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 2510/08 Electric propulsion units
• CPC Class Codes: B60W 2510/087 Temperature
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2555/20 Ambient conditions, e.g. wind or rain
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/1005 : Transmission ratio engaged
• CPC Class Codes: B60W 30/18127 : Regenerative braking
• CPC Class Codes: F16H 2037/0886 : with switching means, e.g. to change ranges
• 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

Abstract

In one embodiment, a hybrid propulsion system for a vehicle is provided. The system comprises at least one drive wheel; a first motor coupled to the drive wheel, said first motor configured to selectively generate electrical energy from kinetic energy received at the drive wheel; a second motor configured to selectively generate electrical energy from kinetic energy received at the drive wheel; a transmission including a first end coupled to the first motor and a second end coupled to the second motor; and a control system configured to vary a level of electrical energy generated by the first motor relative to the second motor in response to a thermal condition of at least one of said first and second motors to provide vehicle braking.

Claims

1. A hybrid propulsion system for a vehicle, comprising:

at least one drive wheel;

a first motor coupled to the drive wheel, said first motor configured to selectively generate electrical energy from kinetic energy received at the drive wheel;

a second motor configured to selectively generate electrical energy from kinetic energy received at the drive wheel;

a transmission including a first end coupled to the first motor and a second end coupled to the second motor; and

a control system configured to vary a level of electrical energy generated by the first motor relative to the second motor in response to a thermal condition of at least one of said first and second motors to provide vehicle braking.

2. The system of claim 1, wherein the transmission includes a plurality of fixed gear ratios and wherein the control system is further configured to adjust a gear ratio of the transmission in response to a level of electrical energy generated by the second motor.

3. The system of claim 1, wherein the thermal condition includes a temperature of at least one of the first motor and the second motor.

4. The system of claim 3, wherein the control system is further configured to reduce the level of electrical energy generated by the first motor relative to the second motor when the temperature of the first motor exceeds a temperature threshold.

5. The system of claim 4 further comprising, a temperature sensor configured to detect the temperature of the first motor, and wherein the temperature sensor is communicatively coupled to the control system.

6. The system of claim 1, wherein the thermal condition includes a temperature of an electrical system of at least one of the first motor and the second motor.

7. The system of claim 1 further comprising an internal combustion engine coupled to the second end of the transmission, wherein the control system is further configured to increase an amount of kinetic energy supplied to the engine from the drive wheel in response to said thermal condition of at least one of the first motor and the second motor to provide vehicle braking.

8. A method of operating a hybrid propulsion system for a vehicle, wherein the hybrid propulsion system includes a first motor coupled to a drive wheel and a second motor coupled to the drive wheel via a transmission, the method comprising:

during a first temperature condition of the first motor, operating at least the first motor to provide a first level of vehicle braking torque responsive to a given vehicle braking request;

during a second temperature condition of the first motor higher than said first temperature condition, operating the first motor to provide a second level of vehicle braking torque less than said first level of braking torque responsive to the given vehicle braking request.

9. The method of claim 8 further comprising, operating the second motor to provide a greater level of braking torque during the second temperature condition than during the first temperature condition responsive to the given vehicle braking request.

10. The method of claim 8 further comprising, operating the transmission with a different torque ratio during the first temperature condition than during the second temperature condition, wherein the transmission transmits a greater level of torque during the second temperature condition than during the first temperature condition.

11. The method of claim 8, wherein the hybrid propulsion system further includes an internal combustion engine, wherein the method further comprises operating the engine during the second temperature condition to provide a greater level of torque than during the first temperature condition.

12. The method of claim 8, wherein the temperature of the first motor is detected by a temperature sensor.

13. The method of claim 8, wherein said given vehicle braking request is received via a user input device.

14. A method of operating a hybrid propulsion system for a vehicle, wherein the hybrid propulsion system includes a first motor coupled to a drive wheel and a vehicle braking device coupled to the drive wheel via a transmission, the method comprising:

receiving a vehicle braking request from a user at a user input device;

in response to said vehicle braking request, adjusting a level of vehicle braking provided by the first motor based on an amount of electrical energy generated by the first motor at said level of vehicle braking provide by the first motor; and

adjusting a level of vehicle braking provided by the vehicle braking device based on said level of vehicle braking provided by the first motor.

15. The method of claim 14, wherein the vehicle braking device includes at least a second motor.

16. The method of claim 15, wherein the vehicle braking device further includes an internal combustion engine.

17. The method of claim 14, wherein the level of vehicle braking provided by the vehicle braking device is adjusted by varying a torque ratio of the transmission.

18. The method of claim 14 further comprising, storing at least a portion of said electrical energy generated by the first motor at an energy storage device onboard the vehicle.

19. The method of claim 14, wherein the level of vehicle braking provided by the vehicle braking device is increased with a decrease in the level of vehicle braking provided by the first motor for a given vehicle braking request.

20. The method of claim 14, further comprising adjusting a level of vehicle braking provided by the first motor based on a temperature of the first motor.