Methods and system for improving efficiency of a hybrid vehicle

• US 9,914,449 B2
• Filed: 01/13/2016
• Issued: 03/13/2018
• 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: Yamazaki, Mark Steven, Lear, Christopher Alan, Thompson, Scott James
• Primary Examiner(s): Amin, Bhavesh V
• Application Number:
  US14/994,554
• Publication Number:
  US 20170197611A1
• Time in Patent Office: 790 Days
• Field of Search: None
• CPC Class Codes: B60K 2006/4825 Electric machine connected or connectable to gearbox input shaft
• CPC Class Codes: B60K 6/48 Parallel 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 10/10 including control of change-speed gearings
• CPC Class Codes: B60W 10/26 for electrical energy, e.g. batteries or capacitors
• CPC Class Codes: B60W 20/11 using model predictive control [MPC] strategies, i.e. control methods based on models predicting performance utilising navigation and traffic information in the control strategy B60W20/12
• CPC Class Codes: B60W 20/13 in order to stay within battery power input or output limits; in order to prevent overcharging or battery depletion
• CPC Class Codes: B60W 20/15 Control strategies specially adapted for achieving a particular effect
• CPC Class Codes: B60W 2050/0075 Automatic parameter input, automatic initialising or calibrating means
• CPC Class Codes: B60W 30/14 Adaptive cruise control
• CPC Class Codes: B60W 30/143 Speed control B60W30/16 takes precedence
• CPC Class Codes: B60W 50/0098 Details of control systems ensuring comfort, safety or stability not otherwise provided for
• CPC Class Codes: Y02T 10/62 Hybrid vehicles

Abstract

Systems and methods for operating a hybrid powertrain that includes an engine and a motor/generator are described. The systems and methods adjust battery charging and discharging as well as engine and motor torque based on whether or not the vehicle is operating in a cruise control mode. In one example, curves that provide a basis for operating an engine and motor based on driver demand torque are compressed during a vehicle cruise control mode to improve powertrain efficiency.

Claims

1. A powertrain operating method, comprising:

distributing a driver demand torque request between an engine and a motor responsive to a first battery charging curve and a first battery discharging curve while not operating a vehicle in cruise control mode via a controller; and

distributing the driver demand torque request between the engine and the motor responsive to a second battery charging curve and a second battery discharging curve while operating the vehicle in cruise control mode via the controller.

2. The method of claim 1, wherein the first battery charging curve is based on engine torque, engine speed, and engine brake specific fuel consumption.

3. The method of claim 2, where the first battery discharging curve is based on engine torque, engine speed, and engine brake specific fuel consumption, where the first battery charging curve is based on a first group of engine torque values, where the first battery discharging curve is based on a second group of engine torque values, and where engine torque values of the second group of engine torque values are greater than the engine torque values of the first group of engine torque values.

4. The method of claim 3, where the second battery charging curve is based on engine torque, engine speed, and engine brake specific fuel consumption.

5. The method of claim 4, where the second battery charging curve is based on a third group of engine torque values, and where engine torque values of the third group of engine torque values are greater than the engine torque values of the first group of engine torque values.

6. The method of claim 5, where the second battery discharging curve is based on engine torque, engine speed, and engine brake specific fuel consumption, where the second battery discharging curve is based on a fourth group of engine torque values, and where the engine torque values of the third group of engine torque values are less than the engine torque values of the second group of engine torque values.

7. A powertrain operating method, comprising:

activating a first battery charging and discharging strategy and operating an engine and an electric machine responsive to the first battery charging and discharging strategy via a controller when not operating a vehicle in cruise control mode; and

activating a second battery charging and discharging strategy and operating the engine and the electric machine responsive to the second battery charging and discharging strategy via the controller when operating the vehicle in cruise control mode.

8. The method of claim 7, further comprising distributing a driver demand torque request between the engine and the electric machine responsive to a first battery charging curve and a first battery discharging curve while not operating the vehicle in cruise control mode, and distributing the driver demand torque request between the engine and the electric machine responsive to a second battery charging curve and a second battery discharging curve while operating the vehicle in cruise control mode.

9. The method of claim 7, where the first battery charging and discharging strategy does not charge or discharge a vehicle battery when a vehicle battery charge is within a first battery state of charge range.

10. The method of claim 9, where the second battery charging and discharging strategy does not charge or discharge the vehicle battery when the vehicle battery charge is within a second battery state of charge range, the second battery state of charge range different from the first battery state of charge range.

11. The method of claim 10, where the first battery charging and discharging strategy includes a desired nominal battery state of charge that is less than a desired nominal battery state of charge of the second battery charging and discharging strategy.

12. The method of claim 11, where vehicle speed is controlled to a desired vehicle speed in the vehicle cruise control mode via adjusting engine and motor torque.

13. The method of claim 7, further comprising shifting a transmission responsive to a first shift schedule when not operating the vehicle in cruise control mode and shifting the transmission responsive to a second shift schedule when operating the vehicle in cruise control mode.

14. A system, comprising:

an engine;

a motor/generator;

a disconnect clutch positioned in a powertrain between the engine and the motor/generator;

a transmission coupled to the motor/generator; and

a controller including executable instructions stored in non-transitory memory to downshift the transmission from a gear at a first driver demand torque while a vehicle is operated in a cruise control mode and downshift the transmission from the gear at a second driver demand torque while the vehicle is not operated in the cruise control mode, and instructions to activate a first battery charging and discharging strategy when not operating the vehicle in the cruise control mode, and further comprising additional instructions to activate a second battery charging and discharging strategy when operating the vehicle in the cruise control mode.

15. The system of claim 14, where the gear is a highest gear in the transmission.

16. The system of claim 14, where the first battery charging and discharging strategy does not charge or discharge a vehicle battery when a vehicle battery charge is within a first battery state of charge range.

17. The system of claim 15, further comprising additional instructions to distribute a driver demand torque request between the engine and the motor/generator responsive to a first battery charging curve and a first battery discharging curve while not operating the vehicle in the cruise control mode.

18. The system of claim 17, further comprising additional instructions to distribute the driver demand torque request between the engine and the motor/generator responsive to a second battery charging curve and a second battery discharging curve while operating the vehicle in the cruise control mode.

19. The system of claim 18, where vehicle speed is controlled to a desired speed in the vehicle cruise control mode via adjusting engine torque and motor torque.