Methods and systems for dual fuel injection system

Patent metadata

Field	Value
Publication number	US-10323595-B2
Application number	US-201715714976-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Dec 21, 2016
Publication date	Jun 18, 2019
Grant date	Jun 18, 2019

Abstract

Methods and systems are provided for reducing lean air-fuel ratio excursions due to degradation of a port injector while fueling an engine via each of port and direct injection. During a PFDI mode of engine operation, responsive to an indication of port injector degradation, such as due to circuit or injector power issues, intake airflow is limited by reducing the opening of an intake throttle. Air flow is limited to be based only on the direct injected fuel fraction, and independent of the commanded port injected fuel fraction.

First claim

The invention claimed is:

1. An engine system, comprising:
an engine cylinder;
a port injector;
a direct injector;
an intake throttle;
a controller with computer-readable instructions stored on non-transitory memory for:
responsive to an indication of port injector degradation, received while fueling the cylinder via only the port injector,
transitioning to fueling the cylinder via only the direct injector; and
limiting an intake air flow.

2. The system of claim 1 , wherein the limiting includes reducing an opening of the intake throttle as a pulse-width commanded to the direct injector increases.

3. The system of claim 1 , wherein the limiting is adjusted to maintain an air-fuel ratio of the cylinder from before the transitioning.

4. The system of claim 1 , wherein the indication of port injector degradation includes one of degradation of an electrical circuit coupled to the port injector and loss of electrical power to the port injector.

5. A method for an engine, comprising:
determining engine operating conditions;
selecting fuel injection mode and schedule based on the determined engine operating conditions;
adjusting air flow based on total fuel flow; and
responsive to an indication of port injector degradation, received while fueling a cylinder via each of a port injector and a direct injector, limiting an intake air flow.

6. The method of claim 5 , further comprising, responsive to the indication, increasing an amount of fuel delivered via the direct injector.

7. The method of claim 5 , wherein limiting the intake air flow includes reducing an intake throttle opening.

8. The method of claim 5 , wherein the limiting is based only on an amount of fuel being delivered to the cylinder via the direct injector.

9. The method of claim 5 , wherein the limiting is independent of an amount of fuel being delivered to the cylinder via the port injector.

10. The method of claim 5 , wherein limiting the intake air flow includes adjusting a variable cam timing.

11. The method of claim 5 , wherein the limiting is adjusted to maintain a combustion air-fuel ratio from before the indication.

12. The method of claim 5 , wherein the indication of port injector degradation includes indication of degradation of a circuit coupled to the port injector.

13. The method of claim 5 , wherein the indication of port injector degradation includes indication of loss of electrical power to the port injector.

14. The method of claim 5 , further comprising, adjusting one or more engine operating parameters based on a torque deficit between actual torque with the limited intake air flow and commanded torque.

15. A method for an engine, comprising:
fueling a cylinder via each of a port injector and a direct injector while operating at an air-fuel ratio; and
responsive to loss of electrical power to the port injector, continuing to fuel the cylinder via the direct injector while maintaining the air-fuel ratio.

16. The method of claim 15 , wherein maintaining the air-fuel ratio includes reducing an intake throttle opening to maintain the air-fuel ratio.

17. The method of claim 16 , further comprising, responsive to loss of electrical power to the port injector while fueling the cylinder via only the port injector, increasing cylinder fueling via the direct injector while reducing the intake throttle opening to maintain the air-fuel ratio from before the loss of electrical power.

18. The method of claim 17 , wherein the intake throttle opening is reduced based only on an amount of fuel being delivered to the cylinder via the direct injector.

19. The method of claim 17 , further comprising, adjusting one or more engine operating parameters based on a torque deficit between actual engine torque with the reduced intake throttle opening and commanded torque.

20. The method of claim 19 , wherein the adjusting includes one or more of lowering an alternator set point, disabling vehicle air conditioning, and advancing spark timing towards MBT.

Assignees

• Ford Global Tech Llc

Inventors

• Sanborn Ethan D
• Thomas Joseph Lyle
• Zhang Xiaoying
• Hollar Paul
• Dusa Daniel

Classifications

• F02D41/221

  relating to the failure of actuators or electrically driven elements · CPC title

• F02D41/3005

  Details not otherwise provided for · CPC title

• F02D2041/224

  Diagnosis of the fuel system · CPC title

• F02D2041/001

  for engines with variable valve actuation · CPC title

• F02D41/0002

  Controlling intake air · CPC title