Hybrid vehicle and a method of control for improved power management

• US 8,296,032 B2
• Filed: 12/16/2008
• Issued: 10/23/2012
• Est. Priority Date: 12/16/2008
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Wang, Qing, Kuang, Ming Lang
• Primary Examiner(s): EL CHANTI, HUSSEIN A
• Application Number:
  US12/335,684
• Publication Number:
  US 20100152936A1
• Time in Patent Office: 1,407 Days
• Field of Search: 701/51, 701 54- 55
• US Class Current: 701/84
• CPC Class Codes: B60K 1/02 comprising more than one electric motor
• CPC Class Codes: B60K 6/365 with the gears having orbital motion
• CPC Class Codes: B60K 6/445 Differential gearing distribution type
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60K 6/52 Driving a plurality of drive axles, e.g. four-wheel drive
• CPC Class Codes: B60K 6/547 the transmission being a stepped gearing
• 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 10/26 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 2510/244 Charge state
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60W 2540/12 Brake pedal position
• CPC Class Codes: B60W 2710/0644 Engine speed
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 30/188 Controlling power parameters of the driveline, e.g. determining the required 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

Abstract

A hybrid vehicle and method of control. The method includes determining an engine torque command based on a request for vehicle acceleration or deceleration, a target power level of the secondary power source, and a current engine power command, determining an engine speed command based on the target power level of the secondary power source, a total engine power command, and vehicle speed, and operating the engine based on the engine torque and engine speed commands.

Claims

1. A method of controlling operation of a hybrid vehicle having an engine and a secondary power source, the method comprising:

determining an engine torque command based on a request for vehicle acceleration or deceleration, a target power level of the secondary power source, and a current engine power command;

determining an engine speed command based on the target power level of the secondary power source, a total engine power command, and vehicle speed; and

operating the engine based on the engine torque and engine speed commands.

2. The method of claim 1 wherein the target power level of the secondary power source and a target engine torque command are based on the request for vehicle acceleration or deceleration, vehicle speed, and a current engine speed.

3. The method of claim 1 wherein the request for vehicle acceleration is based on signals from an accelerator pedal sensor and a brake pedal sensor.

4. The method of claim 1 wherein the total engine power command is based on the request for vehicle acceleration or deceleration and the target power level of the secondary power source.

5. The method of claim 1 wherein determining the engine torque command further comprises setting the engine torque command equal to a target engine torque command when a total amount of power desired from the secondary power source is within operational limits of the secondary power source.

6. The method of claim 1 wherein determining the engine torque command further comprises adjusting a target engine torque value when a total amount of power desired from the secondary power source is not within operational limits of the secondary power source.

7. A method of controlling operation of a hybrid vehicle having an engine and a secondary power source, the method comprising:

determining a target power level of the secondary power source and a target engine torque command based on a request for vehicle acceleration or deceleration;

determining a total engine power command based on the request for vehicle acceleration or deceleration and the target power level of the secondary power source;

determining a total amount of power desired from the secondary power source based on the target power level of the secondary power source and the difference between the total engine power command and a current engine power command;

determining whether the total amount of power desired from the secondary power source is within operational limits;

determining an engine torque command by adjusting the target engine torque command when the total amount of power desired from the secondary power source is not within operational limits;

determining an engine speed command; and

executing the engine torque and engine speed commands to control operation of the engine.

8. The method of claim 7 wherein determining the target power level of the secondary power source and the target engine torque command is based on engine speed, vehicle speed, and the request for vehicle acceleration or deceleration.

9. The method of claim 7 wherein the current engine power command is based on engine speed and a current engine torque command.

10. The method of claim 7 wherein determination of the engine speed command is based on the target power level of the secondary power source, the total engine power command, and vehicle speed.

11. The method of claim 7 wherein adjusting the target engine torque command further comprises increasing the target engine torque command to not exceed a discharge limit value when the total amount of power desired from the secondary power source is a positive value and is greater than the discharge limit value.

12. The method of claim 7 wherein adjusting the target engine torque command further comprises reducing the target engine torque command to not exceed a charge limit value when the total amount of power desired from the secondary power source is not a positive value and is less than the charge limit value.

13. The method of claim 7 wherein the engine torque command and engine speed command maintain engine power along an engine operation path that improves vehicle fuel economy.

14. A hybrid vehicle, comprising:

an electrical machine;

primary and secondary power sources capable of supplying power to the electrical machine; and

a control system including at least one controller configured to;

determine a target power level of the secondary power source, a target torque command for the primary power source, and a total power command for the primary power source based at least on part on a driver input;

determine a total amount of power desired from the secondary power source based on the target power level of the secondary power source, the total power command for the primary power source, and a current power command for the primary power source;

adjust the target torque command for the primary power source when the total amount of power desired from the secondary power source is not within operational limits of the secondary power source; and

apply the target torque command to control the torque provided by the primary power source.

15. The vehicle of claim 14 wherein the controller is further configured to adjust the target primary power source torque command by determining a torque adjustment value for the primary power source based at least in part on an operational limit of the secondary power source.

16. The vehicle of claim 14 wherein the controller is further configured to determine a speed command for the primary power source based on the target power level of the secondary power source, the total power command for the primary power source, and vehicle speed.

17. The vehicle of claim 14 wherein the driver input is provided with at least one of an accelerator pedal and a brake pedal.

18. The vehicle of claim 14 wherein the controller is configured to determine the total power command for the primary power source based on the driver input and the target power level of the secondary power source.

19. The vehicle of claim 14 wherein the target torque command for the primary power source is not adjusted when the total amount of power desired from the secondary power source is within operational limits.

20. The vehicle of claim 14 wherein the controller is further configured to determine a speed command for the primary power source and adjust the target torque command and speed command simultaneously to optimize vehicle fuel efficiency.