EV mode shift strategy for hybrid vehicle

• US 9,783,188 B2
• Filed: 01/13/2016
• Issued: 10/10/2017
• Est. Priority Date: 01/13/2016
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Colvin, Daniel Scott, Lear, Christopher Alan, Nefcy, Bernard D., Burt, Andrew E.
• Primary Examiner(s): FREJD, RUSSELL WARREN
• Application Number:
  US14/994,754
• Publication Number:
  US 20170197609A1
• Time in Patent Office: 636 Days
• Field of Search: None
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/46 Series type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 20/14 in conjunction with braking regeneration
• CPC Class Codes: B60W 20/30 Control strategies involving selection of transmission gear ratio control of change speed gearings, together with other vehicle sub-units B60W10/10; HEV transmission gearing B60K6/36; gearings and control thereof F16H
• CPC Class Codes: B60W 2510/1005 Transmission ratio engaged
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2710/081 Speed
• CPC Class Codes: B60W 2710/086 Power
• CPC Class Codes: B60W 2710/1005 Transmission ratio engaged
• CPC Class Codes: B60W 30/18127 Regenerative braking
• CPC Class Codes: B60Y 2200/92 Hybrid vehicles
• CPC Class Codes: B60Y 2300/18125 Regenerative braking
• CPC Class Codes: B60Y 2300/20 Reducing vibrations in the driveline
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements
• CPC Class Codes: Y10S 903/947 : Characterized by control of braking, e.g. blending of regeneration, friction braking

Abstract

A vehicle includes a generator, a battery, a transmission, and a controller. The generator is configured to recharge the battery at a maximum power output when a generator speed is above a threshold speed. The transmission is configured to downshift during regenerative braking such that the generator speed is maintained above the threshold speed. The controller is programmed to, in response to a decrease in battery temperature corresponding to a decrease in generator speed required to maintain the maximum power output, decrease the threshold speed.

Claims

1. A vehicle comprising:

a generator that recharges a battery at a maximum power when operating above a speed threshold;

a transmission that downshifts during regenerative braking to maintain generator operation above the threshold; and

a controller programmed to, in response to decreasing battery temperature resulting in decreasing generator speed required to generate maximum power, decrease the threshold, and in response to a desired transmission downshift corresponding to system vibrations, maintain a current transmission gear.

2. The vehicle of claim 1, wherein the controller is further programmed to, in response to an increase in battery temperature corresponding to an increase in generator speed required to maintain the maximum power output, increase the threshold.

3. The vehicle of claim 1, wherein the threshold is within a constant maximum power output region of the generator.

4. The vehicle of claim 1, wherein the threshold is within a constant maximum torque output region of the generator.

5. The vehicle of claim 1, wherein the controller is further programmed to, in response to a desired upshift of the transmission corresponding to a speed of the generator decreasing below a minimum speed required to operate a transmission fluid pump to maintain a minimum transmission fluid pressure, maintain a current gear of the transmission.

6. A vehicle comprising:

a generator configured to recharge a battery at a maximum power output when a generator speed is above a threshold speed;

a transmission configured to downshift during regenerative braking such that the generator speed is maintained above the threshold speed; and

a controller programmed to, in response to an increase in battery temperature corresponding to an increase in generator speed required to maintain the maximum power output, increase the threshold speed, and in response to a desired upshift of the transmission corresponding to the generator speed decreasing below a minimum speed required to operate a transmission fluid pump to maintain a minimum transmission fluid pressure, maintain a current gear of the transmission.

7. The vehicle of claim 6, wherein the controller is further programmed to, in response to a decrease in battery temperature corresponding to a decrease in generator speed required to maintain the maximum power output, decrease the threshold speed.

8. The vehicle of claim 6, wherein the threshold speed is within a constant maximum power output region of the generator.

9. The vehicle of claim 6, wherein the threshold speed is within a constant maximum torque output region of the generator.

10. The vehicle of claim 6, wherein the controller is further programmed to, in response to a desired downshift of the transmission corresponding to system vibrations, maintain a current gear of the transmission.

11. A vehicle comprising:

an electric machine configured to recharge a battery during regenerative braking;

a transmission configured to shift during regenerative braking to maintain a minimum electric machine speed corresponding to a lower threshold speed of a maximum power output region, and configured to upshift during regenerative braking to decrease the speed of the electric machine if the speed of the electric machine exceeds the lower threshold speed by an allowable deviation such that a difference between the speed of the electric machine and the lower threshold speed is less than the allowable deviation and the speed of the electric machine is maintained above the lower threshold speed; and

a controller programmed to, in response to a decrease in battery temperature corresponding to a decrease in electric machine speed required to maintain the maximum power output, decrease the lower threshold speed.

12. The vehicle of claim 11, wherein the controller is further programmed to, in response to an increase in battery temperature corresponding to an increase in electric machine speed required to maintain the maximum power output, increase the lower threshold speed.

13. The vehicle of claim 11, wherein the lower threshold speed is within a constant maximum torque output region of the electric machine.

14. The vehicle of claim 11, wherein the transmission is configured to downshift during regenerative braking to increase the speed of the electric machine such that the electric machine speed is maintained above the lower threshold speed.

15. The vehicle of claim 14, wherein the controller is further programmed to, in response to a desired downshift of the transmission corresponding to system vibrations, maintain a current gear of the transmission.

16. The vehicle of claim 11, wherein the controller is further programmed to, in response to a desired upshift of the transmission corresponding to a speed of the electric machine decreasing below a minimum speed required to operate a transmission fluid pump to maintain a minimum transmission fluid pressure, maintain a current gear of the transmission.