SYSTEM AND METHOD FOR CONTROLLING HYBRID VEHICLE

• US 20160244049A1
• Filed: 02/22/2016
• Published: 08/25/2016
• Est. Priority Date: 02/20/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: CRISP, Nicholas Dashwood, TUFAIL, Khizer, PETRIDIS, Anthemios Philemon
• Granted Patent: US 10,131,344 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60K 6/485 Motor-assist type
• 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 20/19 for achieving enhanced acceleration
• 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 2510/244 Charge state
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/93 Conjoint control of different elements
• CPC Class Codes: Y10S 903/945 Characterized by control of gearing, e.g. control of transmission ratio

Abstract

A hybrid vehicle and method for reducing fuel consumption include upper and lower engine speed limits set based upon whether the state of charge of a battery electrically connected to an electric machine, which may be implemented by an integrated starter-generator is sufficiently high to permit the electric machine to provide a temporary torque boost to an engine of the motor vehicle. If the state of charge of the battery is sufficiently high to permit temporary torque boosting, then the upper and lower engine speed limits are reduced from baseline upper and lower limits to adjusted upper and lower limits to reduce fuel consumption of the engine without adversely affecting NVH.

Claims

1. A method for controlling a hybrid vehicle, comprising:

initiating, by a controller, a gear shift of a multi-speed transmission in response to engine speed crossing one of a first engine speed threshold associated with a battery state of charge being above a battery state of charge threshold, and a second engine speed threshold otherwise.

2. The method of claim 1, the battery state of charge threshold based upon whether the state of charge of the battery is sufficient to permit an electric machine to be used to provide a temporary torque boost to an engine of the hybrid vehicle.

3. The method of claim 1, the first engine speed threshold being less than the second engine speed threshold.

4. The method of claim 1, wherein the gear shift is an upshift to a higher gear and the first engine speed threshold is an engine upper speed limit for the engine when using a current gear ratio.

5. The method of claim 1, the multi-speed transmission comprising a transmission in which a driver manually effects changes in gear ratio and wherein initiating the gear shift comprises generating an alert to the driver to upshift the transmission.

6. The method of claim 1, the multi-speed transmission comprising an automatic transmission, wherein initiating the gear shift comprises automatically upshifting the transmission when the engine speed crosses above the first engine speed threshold.

7. The method of claim 1, wherein the gear shift is a downshift to a lower gear and the first engine speed threshold is an engine lower speed limit for the engine when using a current gear ratio.

8. A vehicle comprising:

an engine;

an electric machine coupled to the engine;

a battery coupled to the electric machine;

a multi-speed transmission coupled to the engine; and

a controller programmed to generate a transmission gear shift signal for the multi-speed transmission in response to engine speed crossing an engine speed threshold that is based on a state of charge of the battery.

9. The vehicle of claim 8, the controller further programmed to generate a transmission upshift signal in response to engine speed exceeding the engine speed threshold and the state of charge of the battery exceeding a state of charge threshold.

10. The vehicle of claim 9, the engine speed threshold being lower than a baseline threshold in response to the state of charge of the battery exceeding the state of charge threshold.

11. The vehicle of claim 8, the multi-speed transmission comprising a manual transmission wherein generating the transmission gear shift signal comprises energizing a gear shift indicator.

12. The vehicle of claim 11 wherein the gear shift indicator comprises at least one of a visual indicator, a haptic indicator, and an audible indicator.

13. The vehicle of claim 8, the multi-speed transmission comprising an automatic transmission wherein generating the transmission gear shift signal comprises controlling the automatic transmission to upshift when the engine speed crosses the engine speed threshold and the state of charge of the battery exceeds a state of charge threshold, the engine speed threshold being less than a baseline engine speed threshold corresponding to the state of charge of the battery being below the state of charge threshold.

14. The vehicle of claim 8, the electric machine comprising an integrated starter-generator.

15. The vehicle of claim 14 wherein the integrated starter-generator comprises a belt integrated starter-generator driveably connected via a drive belt to a crankshaft of the engine.

16. A hybrid vehicle having an engine, an electric machine, a battery, and a multi-speed transmission, comprising:

a processor programmed to control shifting of the transmission in response to engine speed crossing one of a first upshift threshold associated with the battery being above a threshold state of charge, and a second upshift threshold higher than the first upshift threshold associated with the battery not being above the threshold state of charge.

17. The hybrid vehicle of claim 16, the processor generating a transmission upshift signal in response to the engine speed exceeding one of the first and second upshift thresholds.

18. The hybrid vehicle of claim 16, the processor further programmed to control shifting of the transmission in response to engine speed crossing one of a first downshift threshold associated with the battery being below the threshold state of charge, and a second downshift threshold lower than the first downshift threshold associated with the battery not being below the threshold state of charge.

19. The hybrid vehicle of claim 18, the processor generating a transmission downshift signal in response to the engine speed being below the first downshift threshold.

20. The hybrid vehicle of claim 16, the electric machine comprising an integrated starter-generator.