Method for optimizing powertrain efficiency for a vehicle

• US 8,103,397 B2
• Filed: 06/10/2010
• Issued: 01/24/2012
• Est. Priority Date: 06/10/2010
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Liang, Wei, Wang, Qing, Wang, Xiaoyong, Supina, Joseph Gerald, McGee, Ryan Abraham, Kuang, Ming Lang
• Primary Examiner(s): Jeanglaude, Gertrude Arthur
• Application Number:
  US12/797,964
• Publication Number:
  US 20110172865A1
• Time in Patent Office: 593 Days
• Field of Search: 701/10, 701/22, 903/903, 180/65.265, 180/65.275, 236/74.R
• US Class Current: 701/22
• CPC Class Codes: B60K 6/445 Differential gearing distribution 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 20/00 Control systems specially adapted for hybrid vehicles hybrid vehicle design, B60K6/00; electric vehicles B60L
• CPC Class Codes: B60W 20/12 using control strategies taking into account route information estimation or calculation of non-directly measurable driving parameters B60W40/00
• CPC Class Codes: B60W 2510/085 Power
• CPC Class Codes: B60W 30/1882 characterised by the working point of the engine, e.g. by using engine output chart
• CPC Class Codes: Y02T 10/62 Hybrid vehicles
• CPC Class Codes: Y10S 903/903 having energy storing means, e.g. battery, capacitor

Abstract

A vehicle powertrain includes an engine, an electric machine operable to output torque to at least one vehicle wheel, and an electric power source operable to provide electric power to the electric machine. A method for optimizing powertrain efficiency includes generating a plurality of three-dimensional maps of optimized engine speeds for combinations of vehicle power and vehicle speed at a plurality of predetermined powers of the electrical power source. Each of the maps corresponds to one of the predetermined powers of the electrical power source. The maps are used to determine an optimized engine speed for a given power of the electrical power source, a given vehicle power and a given vehicle speed.

Claims

1. A method for optimizing powertrain efficiency in a vehicle, the powertrain including an engine, an electric machine operable to output torque to at least one vehicle wheel, and an electrical power source operable to provide electrical power to the electric machine, the method comprising:

generating a plurality of three-dimensional maps of optimized engine speeds for combinations of vehicle power and vehicle speed at a plurality of predetermined powers of the electrical power source, each of the maps corresponding to one of the predetermined powers of the electrical power source; and

using the maps to determine an optimized engine speed for a given power of the electrical power source, a given vehicle power and a given vehicle speed.

2. The method of claim 1, wherein the vehicle includes a control system including at least one controller, and the maps are programmed into the control system to create a four-dimensional map defined by values of:

the vehicle power, the vehicle speed, the power of the electrical power source, and the optimized engine speed.

3. The method of claim 2, wherein the three-dimensional maps are generated offline prior to being programmed into the control system.

4. The method of claim 1, wherein the optimized engine speeds used in the three-dimensional maps are generated from a powertrain efficiency equation that is a function of at least the engine speed, the vehicle power, the vehicle speed, and the power of the electrical power source, each of the optimized engine speeds corresponding to an engine speed value that maximizes the powertrain efficiency for a given combination of vehicle power, vehicle speed, and power of the electrical power source.

5. The method of claim 1, further comprising:

generating an engine power value based on the given vehicle power and the given power of the electrical power source; and

using the determined optimized engine speed and the generated engine power value to generate an engine torque value.

6. A method for optimizing powertrain efficiency in a vehicle, the powertrain including an engine, an electric machine operable to output torque to at least one vehicle wheel, and an electrical power source operable to provide electrical power to the electric machine, the method comprising:

determining a powertrain efficiency as a function of engine speed for one set of values of certain vehicle operating parameters, including a power of the electrical power source;

maximizing the powertrain efficiency for the one set of values; and

determining the optimized engine speed for the one set of values based on the maximized powertrain efficiencies.

7. The method of claim 6, wherein the one set of values is a set of current operating conditions for the certain vehicle operating parameters.

8. The method of claim 6, further comprising:

determining a powertrain efficiency as a function of engine speed for at least one other set of values for the certain vehicle operating parameters;

maximizing the powertrain efficiency for the at least one other set of values, each of the maximized powertrain efficiencies corresponding to an optimized engine speed for the respective set of values;

determining current values for the certain vehicle operating parameters; and

determining the optimized engine speed for the current values of the certain vehicle operating parameters based on the maximized powertrain efficiencies.

9. The method of claim 6, wherein the certain vehicle operating parameters further include a vehicle power and a vehicle speed.

10. The method of claim 9, further comprising:

generating an engine power value from the current values of the vehicle power and the power of the electrical power source; and

using the determined optimized engine speed and the generated engine power value to generate an engine torque value.

11. The method of claim 9, further comprising storing each of the sets of values and the corresponding optimized engine speeds in a multi-dimensional map, the step of determining the optimized engine speed for the current values of the vehicle operating parameters including locating the current values of the vehicle operating parameters on the multi-dimensional map and determining the corresponding optimized engine speed.

12. The method of claim 9, wherein the vehicle includes a control system having at least one controller, the method further comprising programming into the control system the optimized engine speeds and the respective sets of values for the certain vehicle operating parameters.

13. The method of claim 12, wherein the steps of determining the powertrain efficiencies and maximizing the powertrain efficiencies are performed offline prior to being programmed into the control system.

14. A method for optimizing powertrain efficiency in a vehicle, the powertrain including an engine, an electric machine operable to output torque to at least one vehicle wheel, and an electrical power source operable to provide electrical power to the electric machine, the method comprising:

inputting into a control system of the vehicle current values of a plurality of vehicle operating parameters, including a power of the electrical power source, the control system being programmed to output optimized engine speeds corresponding to respective values of the vehicle operating parameters; and

outputting the optimized engine speed corresponding to the current values of the vehicle operating parameters.

15. The method of claim 14, wherein the optimized engine speed is defined as an engine speed that maximizes powertrain efficiency for a given set of values of the vehicle operating parameters.

16. The method of claim 15, wherein the vehicle operating parameters further include a vehicle power and a vehicle speed.

17. The method of claim 16, further comprising:

generating an engine power value from the current values of the vehicle power and the power of the electrical power source; and

using the determined output engine speed and the generated engine power value to generate an engine torque value.

18. The method of claim 16, further comprising:

determining optimized engine speeds corresponding to different combinations of the vehicle operating parameters; and

programming the optimized engine speeds and respective combinations of the vehicle operating parameters into the control system for later retrieval.

19. The method of claim 18, wherein the step of determining the optimized engine speeds corresponding to different combinations of the vehicle operating parameters is performed offline prior to programming the optimized engine speeds and respective combinations of the vehicle operating parameters into the control system.