Methods and systems for starting an engine while a vehicle is creeping

Patent metadata

Field	Value
Publication number	US-2016016580-A1
Application number	US-201414331853-A
Country	US
Kind code	A1
Filing date	Jul 15, 2014
Priority date	Jul 15, 2014
Publication date	Jan 21, 2016
Grant date	—

Abstract

Systems and methods for starting an engine of a hybrid vehicle that is in a creep mode are presented. In one example, a torque converter lockup clutch is released and vehicle speed is closed loop controlled in response to a request to start an engine. The vehicle speed is controlled so that a torque disturbance related to closing a driveline disconnect clutch may be reduced.

First claim

1 . A driveline method, comprising:
opening a locked torque converter clutch during a creep mode in response to a request to start an engine; increasing a torque converter impeller speed in response to the request to start the engine, where the torque converter impeller speed is increased to a desired engine idle speed; and closing a driveline disconnect clutch in response to the impeller speed and the engine reaching the desired engine idle speed or operating the engine at idle speed without closing the driveline disconnect clutch.

2 - 3 . (canceled)

4 . The method of claim 1 , where an electric machine provides torque to a driveline during the creep mode.

5 . The method of claim 4 , where the electric machine is positioned between a torque converter and the driveline disconnect clutch.

6 . The method of claim 1 , where the torque converter impeller speed is increased via an electric machine.

7 . The method of claim 1 , further comprising exiting the creep mode in response to application of a brake pedal or an accelerator pedal.

8 . A driveline method, comprising:
opening a locked torque converter clutch during a creep mode in response to a request to start an engine; increasing a torque converter impeller speed in response to the request to start the engine; entering a closed loop vehicle speed control mode in response to the request to start the engine; and closing a driveline disconnect clutch in response to torque converter impeller speed matching an engine speed or operating the engine at idle speed without closing the driveline disconnect clutch.

9 . The method of claim 8 , where the closed loop vehicle speed control mode includes subtracting actual vehicle speed from desired vehicle speed.

10 . The method of claim 9 , further comprising increasing brake force in response to actual vehicle speed being greater than desired vehicle speed.

11 . The method of claim 8 , further comprising exiting the closed loop vehicle speed control mode in response to a driver applying a brake pedal or an accelerator pedal.

12 . The method of claim 8 , where the torque converter impeller speed is increased to a desired engine idle speed via an electric machine.

13 . The method of claim 8 , further comprising exiting the closed loop vehicle speed control mode in response to an amount of time elapsing.

14 . (canceled)

15 . A driveline system, comprising:
an engine; an electric machine; a disconnect clutch for selectively coupling the engine and the electric machine; a torque converter including a lockup clutch coupled to the electric machine; and a controller including executable instructions stored in non-transitory memory for opening the lockup clutch from a locked state during a vehicle creep mode in response to a request to start the engine, and additional instructions to close the disconnect clutch in response to the electric machine and the engine achieving a desired engine idle speed.

16 . The driveline system of claim 15 , further comprising additional instructions to accelerate the electric machine to the desired engine idle speed in response to the request to start the engine.

17 . (canceled)

18 . The driveline system of claim 16 , further comprising additional instructions to exit the vehicle creep mode in response to a driver applying an accelerator pedal.

19 . The driveline system of claim 16 , further comprising additional instructions to enter closed loop vehicle speed control in response to the request to start the engine.

20 . The driveline system of claim 19 , where vehicle speed is controlled in the closed loop vehicle speed control via the controller applying vehicle brakes.

Assignees

• Ford Global Tech Llc

Inventors

• Johri Rajit
• Wang Xiaoyong
• Thompson Scott James
• Doering Jeffrey Allen

Classifications

• Y02T10/62

  Hybrid vehicles · CPC title

• Y10S903/93

  Conjoint control of different elements · CPC title

• B60W10/026

  of lock-up clutches · CPC title

• B60W2030/206

  related or induced by the engine · CPC title

• B60W30/20

  Reducing vibrations in the driveline · CPC title