Hybrid vehicle launching methods and system

Patent metadata

Field	Value
Publication number	US-11338794-B2
Application number	US-201916391225-A
Country	US
Kind code	B2
Filing date	Apr 22, 2019
Priority date	Apr 22, 2019
Publication date	May 24, 2022
Grant date	May 24, 2022

Abstract

Methods and systems are provided for operating a hybrid vehicle during launch conditions from rest. In one example, a threshold speed below which a clutch is closed during a vehicle launch is adjusted so that driver demand wheel torque is held constant for a constant accelerator pedal position until the clutch is closed.

First claim

The invention claimed is:

1. A vehicle operating method, comprising:
subdividing an accelerator pedal and vehicle speed map into at least three sections;
adjusting a breakpoint in one of the at least three sections relative to vehicle speed; and
generating a driver demand wheel torque that is constant via an electric machine for a constant accelerator pedal position at vehicle speeds lower than a vehicle speed of the breakpoint, and decreasing the driver demand wheel torque at vehicle speeds greater than the vehicle speed of the breakpoint.

2. The method of claim 1 , where the breakpoint is a vehicle speed where the driver demand wheel torque begins decreasing as vehicle speed increases.

3. The method of claim 1 , where adjusting the breakpoint includes adjusting a vehicle speed of the breakpoint responsive to adjusting engine idle speed.

4. The method of claim 1 , where adjusting the breakpoint includes adjusting a vehicle speed of the breakpoint responsive to a requested vehicle creep speed.

5. The method of claim 1 , where adjusting the breakpoint includes adjusting a vehicle speed of the breakpoint responsive to road grade.

6. The method of claim 1 , further comprising engaging a clutch of a driveline in response to rotational speed of a transmission input shaft being substantially equal to engine crankshaft rotational speed.

7. The method of claim 6 , where the clutch is engaged at a vehicle speed that is less than a vehicle speed of the breakpoint in the accelerator pedal and the vehicle speed map.

8. The method of claim 1 , where the constant accelerator pedal position is maintained as the driver demand wheel torque decreases.

9. A vehicle operating method, comprising:
generating a driver demand wheel torque that is constant via an electric machine for vehicle speed less than a threshold speed responsive to a constant accelerator pedal position;
decreasing the driver demand wheel torque for vehicle speeds greater than the threshold speed responsive to the constant accelerator pedal position;
adjusting the threshold speed responsive to vehicle operating conditions; and
commanding engagement of a driveline clutch only at vehicle speeds below the threshold speed.

10. The method of claim 9 , where the threshold speed is a speed between an engine idle speed and not to be exceeded clutch engagement speed.

11. The method of claim 9 , where adjusting the threshold includes adjusting the threshold responsive to a vehicle mode selection.

12. The method of claim 9 , where adjusting the threshold includes adjusting the threshold responsive to road grade.

13. The method of claim 9 , where adjusting the threshold includes adjusting the threshold responsive to a temperature of the clutch.

14. The method of claim 9 , where adjusting the threshold includes adjusting the threshold responsive to the driver demand wheel torque.

15. The method of claim 9 , further comprising commanding disengagement of the driveline clutch at an engine idle speed.

16. A driveline system, comprising:
an engine;
a transmission including a clutch coupled to the internal combustion engine;
an electric machine coupled to an axle;
an accelerator pedal; and
a controller including executable instructions stored in non-transitory memory to adjust a threshold speed, the threshold speed adjusted to a speed equal to or above an idle speed of the engine and less than or equal to a threshold engagement speed of the clutch, the threshold speed adjusted responsive to a vehicle operating mode, and engaging the clutch at a speed below the threshold speed during a vehicle launch.

17. The driveline system of claim 16 , further comprising additional executable instructions stored in non-transitory memory to generate a driver demand wheel torque that is constant in response to a constant position of the accelerator pedal during the vehicle launch before engaging the clutch.

18. The driveline system of claim 17 , further comprising additional executable instructions stored in non-transitory memory to reduce the driver demand wheel torque while the accelerator pedal is at the constant position after engaging the clutch.

19. The driveline system of claim 16 , further comprising additional executable instructions stored in non-transitory memory to increase the driver demand wheel torque in response to decelerating a vehicle after the launch while the accelerator pedal is at a constant position.

20. The driveline system of claim 16 , further comprising additional executable instructions stored in non-transitory memory to adjust the threshold speed responsive to road grade.

Assignees

• Ford Global Tech Llc

Inventors

• Meyer Jason
• Ruybal Kevin
• Paradkar Bhavesh
• Mccullough Todd

Classifications

• Y02T10/40

  Engine management systems · CPC title

• B60W2510/1015

  Input shaft speed, e.g. turbine speed · CPC title

• B60W2555/20

  Ambient conditions, e.g. wind or rain · CPC title

• B60W2710/021

  Clutch engagement state · CPC title

• B60W2540/10

  Accelerator pedal position · CPC title