System and Method of Torque Transmission Using an Electric Energy Conversion Device

• US 20080196954A1
• Filed: 02/21/2007
• Published: 08/21/2008
• Est. Priority Date: 02/21/2007
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Soliman, Ihab, Silveri, Andrew
• Granted Patent: US 7,891,450 B2
• Time in Patent Office: Days
• US Class Current: 180/65.25
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• CPC Class Codes: B60W 10/026 of lock-up clutches
• 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 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 2510/0657 Engine torque
• CPC Class Codes: B60W 2510/084 Torque change rate
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

A hybrid vehicle propulsion system including, an internal combustion engine, a torque converter including a lockup clutch, the torque converter receiving torque from at least the internal combustion engine, a multiple fixed-ratio transmission having an input and an output, the input coupled to the torque converter, a electric energy conversion device coupled downstream of the multiple fixed-ratio transmission output, and a control system for adjusting torque output of the hybrid propulsion system, the control system adjusting torque output of the electric energy conversion device to reduce a transmission output torque load and adjusting the multiple fixed ratio transmission to cause a transition in torque transfer responsive to adjusted torque output of the electric energy conversion device.

Claims

1. A hybrid vehicle propulsion system comprising:

an internal combustion engine;

a torque converter including a lockup clutch, the torque converter receiving torque from at least the internal combustion engine;

a multiple fixed-ratio transmission having an input and an output, the input coupled to the torque converter;

a electric energy conversion device coupled downstream of the multiple fixed-ratio transmission output; and

a control system for adjusting torque output of the hybrid propulsion system, the control system adjusting torque output of the electric energy conversion device to reduce a transmission output torque load and adjusting the multiple fixed ratio transmission to cause a transition in torque transfer responsive to adjusted torque output of the electric energy conversion device.

2. The system of claim 1 wherein the transition in torque transfer of the multiple fixed-ratio transmission includes shifting from a current gear ratio of the multiple fixed-ratio transmission to a subsequent gear ratio upon a first condition, and adjusting the multiple fixed-ratio transmission to shift from the current gear ratio to the subsequent gear ratio upon a second condition different than the first condition based on the torque output of the electric energy conversion device.

3. The system of claim 2 wherein the first condition occurs at a lower engine speed than the second condition as torque output of the electric energy conversion device increases.

4. The system of claim 1 wherein the control system adjusts torque output of the internal combustion engine responsive to the adjusted torque output of the energy conversion device.

5. The system of claim 1 further comprising a second electric energy conversion device for supplying torque to the torque converter.

6. The system of claim 5 wherein the control system adjusts the first electric energy conversion device and the second electric energy conversion device during the transition in torque transfer of the multiple fixed-ratio transmission.

7. The system of claim 1 wherein the electric energy conversion device provides torque to at least a front wheel.

8. The system of claim 1 wherein the electric energy conversion device provides torque to at least a rear wheel.

9. A hybrid vehicle propulsion system comprising:

an internal combustion engine coupled to a first electric energy conversion device;

a torque converter having an input and an output, the input coupled to at least one the internal combustion engine and the first electric energy conversion device;

a multiple fixed-ratio transmission having an input and an output, the input coupled to the torque converter output;

a second electric energy conversion device coupled downstream of the multiple fixed-ratio transmission output; and

a control system for the hybrid propulsion system, the control system directing engine output torque between a first propulsion path and a second different propulsion path, the first propulsion path including at least one of the first electric energy conversion device and the second electric energy conversion device and the second propulsion path including at least the transmission input, and adjusting at least one of a torque transfer ratio of the mixed fixed-ratio transmission and a state of the torque converter as the torque transfer between the first and second propulsion paths varies.

10. The system of claim 9 wherein the controller adjusts the multiple fixed-ratio transmission to shift from a current gear ratio to a subsequent gear ratio at a first engine speed during a first condition where more torque is directed to the first propulsion path than the second propulsion path, and adjusts the transmission to shift from the current gear ratio to the subsequent gear ratio at a second engine speed higher than the first engine speed during a second condition where more torque is directed to the second propulsion path than the first propulsion path.

11. The system of claim 9 wherein at least some torque directed to the first propulsion path is converted into electric energy by the first electric energy conversion device to charge the battery.

12. The system of claim 9 wherein at least some torque directed to the first propulsion path is directed to the second electric energy conversion device to produce output torque of the hybrid vehicle.

13. The system of claim 9 where during an operating condition the control system directs torque to the first propulsion path to operate the second electric energy conversion device to reduce torque differential across the torque converter such that the control system can adjust the torque converter to a locked state.

14. The system of claim 13 wherein the control system directs torque to the first propulsion path and adjusts the first and second electric energy conversion devices to adjust the torque converter to locked state.

15. The system of claim 13 wherein during the operating condition the torque differential across the torque converter is such that the torque converter could not be placed in a locked state without assistance in reducing the torque differential.

16. A method of adjusting torque output of a hybrid propulsion system, the hybrid propulsion system including an internal combustion engine, a torque converter having an input and an output, the internal combustion engine coupled to the input of the torque converter, a multiple fixed-ratio transmission having and input and an output, input of the internal combustion engine coupled to the output of the torque converter, and an electric energy conversion device coupled downstream of the output of the multiple fixed-ratio transmission, the method comprising:

adjusting the state of the torque converter to at least one of a locked and unlocked state upon a first condition; and

adjusting the state of the torque converter to the at least one of a locked and unlocked state upon a second condition different from the first condition, wherein the first condition and the second condition differ based on torque output of the electric energy conversion device.

17. The method of claim 16 further comprising:

shifting the multiple fixed-ratio transmission from a current gear ratio to a subsequent gear ratio upon a third condition; and

shifting the multiple fixed-ratio transmission form the current gear ratio to the subsequent gear ratio upon a fourth condition different from the third condition, wherein the third condition and the fourth condition differ based on the torque output of the electric energy conversion device.

18. The method of claim 16 wherein the hybrid propulsion system further includes a second electric energy conversion device coupled to at least one of the internal combustion engine and the torque converter, the method further comprising:

adjusting the state of the torque converter to at least one of a locked and unlocked state based on torque output put of the second electric energy conversion device.

19. The method of claim 18 wherein adjusting the state of the torque converter to the at least one of a locked and unlocked state is based on torque output of the first electric energy conversion device and the second electric energy conversion device.

20. The method of claim 16 wherein the first condition occurs at a lower engine speed than the second condition when the electric energy conversion device generates output torque.