Methods and system for controlling an engine

Patent metadata

Field	Value
Publication number	US-11745720-B2
Application number	US-202117449209-A
Country	US
Kind code	B2
Filing date	Sep 28, 2021
Priority date	Sep 28, 2021
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

Systems and methods for operating a hybrid vehicle are described. In one example, the automatic engine stopping may be inhibited so that an engine may be restarted during change of mind conditions without generating a large driveline torque disturbance. The engine stopping may be inhibited based on a inhibit engine pull-down torque threshold.

First claim

The invention claimed is:

1. A method for operating a powertrain, comprising:
adjusting an inhibit engine pull-down torque threshold based on a vehicle drive history, wherein the vehicle drive history is based on a plurality of tip-ins; and then, after adjusting the inhibit engine pull-down torque,
inhibiting automatic engine stopping based on the adjusted inhibit engine pull-down torque threshold.

2. The method of claim 1 , where the inhibit engine pull-down torque threshold is also a function of a vehicle drive mode.

3. The method of claim 2 , where the inhibit engine pull-down torque threshold is also a function of an active change of mind engine cranking torque reserve.

4. The method of claim 1 , where automatic engine stopping is inhibited in response to a maximum electric machine torque minus a driver demand torque being less than the inhibit engine pull-down torque.

5. The method of claim 1 , where the vehicle driving history is characterized as aggressive or passive.

6. A system, comprising:
an engine;
an integrated starter/generator (ISG);
a driveline disconnect clutch positioned between the engine and the ISG;
a torque converter; and

a controller including executable instructions stored in non-transitory memory that cause the controller to maintain a driveline disconnect clutch line pressure during an engine shutdown, and that cause the controller to inhibit automatic engine stopping based on an inhibit engine pull-down torque threshold, the inhibit engine pull-down torque threshold based on a torque reserve that is a function of an engine cranking torque and engine temperature.

7. The system of claim 6 , where the engine shutdown begins when fuel ceases to be supplied to an engine cylinder.

8. The system of claim 7 , where the engine shutdown ends when engine rotational speed is zero.

9. The system of claim 6 , where the inhibit engine pull-down torque threshold is also a function of an active change of mind torque reserve.

10. The system of claim 7 , further comprising additional instructions to open the driveline disconnect clutch in response to a driver demand pedal position.

11. The system of claim 10 , further comprising additional instructions to close the driveline disconnect clutch in response to an increasing driver demand pedal position.

12. The system of claim 6 , where the driveline disconnect clutch line pressure is maintained during the engine shutdown via modulating a position of a valve.

13. A method for operating a powertrain, comprising:
inhibiting automatic engine stopping based on an inhibit engine pull-down torque threshold, the inhibit engine pull-down torque threshold a function of an active change of mind torque reserve, where the active change of mind torque reserve is a function of an engine cranking torque and engine temperature.

14. The method of claim 13 , where inhibiting automatic engine stopping based on the inhibit engine pull-down torque threshold includes inhibiting automatic engine stopping based on a maximum electric machine torque minus a driver demand torque being less than the inhibit engine pull-down torque threshold.

15. The method of claim 13 , further comprising maintaining a driveline disconnect clutch line pressure during an engine shutdown.

16. The method of claim 15 , where the driveline disconnect clutch line pressure is maintained via modulating a position of a valve.

Assignees

• Ford Global Tech Llc

Inventors

• Ravichandran Maruthi
• Bichkar Akshay
• Meyer Jason
• Johri Rajit

Classifications

• B60W10/06 Primary

  including control of combustion engines · CPC title

• B60W10/02

  including control of driveline clutches · CPC title

• B60W10/08

  including control of electric propulsion units, e.g. motors or generators · CPC title

• B60W20/40

  Controlling the engagement or disengagement of prime movers, e.g. for transition between prime movers {(power-up or power-down of the driveline B60W30/192)} · CPC title

• F02N11/04 Primary

  the motors being associated with current generators · CPC title