Granted Patent B1

US 7,069,911 · App. 11/043,221 · Granted Jul 4, 2006

Abstract

Claims (75)

1. A method of controlling engine operation in a vehicle in response to a misfire of one of a plurality of engine cylinders fueled through a plurality of fuel injectors, the vehicle further including a storage canister in which fuel vapor can be collected and from which the fuel vapor can be purged for delivery to the cylinders, said method comprising:

disabling at least one of the fuel injectors;

using an open loop to control fuel delivery by the injectors to the cylinders;

disabling purging of the canister, wherein said disabling and using steps are performed while the misfire continues;

evaluating a user demand for engine power from the vehicle, using at least one of a throttle position and a pedal position of the vehicle; and

reversing said disabling and using steps based on said evaluating step.

2. The method of claim 1 , further comprising:

verifying whether the at least one disabled fuel injector corresponds to the misfiring cylinder; and

reversing said disabling and using steps based on said verifying step.

3. The method of claim 1 , further comprising:

periodically re-enabling the at least one disabled injector;

testing whether misfire occurs in a cylinder associated with the at least one re-enabled injector; and

reversing said disabling and using steps based on said testing step.

4. The method of claim 3 , performed during engine operation.

5. The method of claim 1 , wherein the vehicle further includes a misfire sensing module and a control module that provides a misfire diagnostic based on input from the misfire sensing module, said method further comprising:

determining whether the misfire is indicated by a reliable misfire diagnostic; and

reversing said disabling and using steps based on said determining step.

6. The method of claim 5 , wherein determining whether the misfire is indicated by a reliable misfire diagnostic comprises determining whether the control module has not provided a diagnostic for a predetermined period of time.

7. The method of claim 5 , wherein determining whether the misfire is indicated by a reliable misfire diagnostic comprises determining whether the engine is operating in a particular operating region.

8. The method of claim 1 , further comprising:

determining whether the misfire has switched to one or more other cylinders; and

reversing said disabling and using steps based on said determining step.

9. The method of claim 1 , further comprising:

testing whether a condition in the vehicle that prompted performance of said disabling and using steps has disappeared; and

reversing said disabling and using steps based on said testing step.

10. The method of claim 1 , further comprising:

checking a previously activated diagnostic trouble code (DTC); and

reversing said disabling and using steps if the DTC is not activated.

11. A system for controlling engine operation in a vehicle in response to a misfire of one of a plurality of engine cylinders fueled through a plurality of fuel injectors, the vehicle further including an engine exhaust catalytic converter and a storage canister in which fuel vapor can be collected and from which the fuel vapor can be purged for delivery to the cylinders, said system comprising:

a misfire sensing module that senses the misfire; and

a control module that provides a misfire diagnostic based on input from said misfire sensing module, and, based on the diagnostic and to prevent unburned fuel from entering the catalytic converter:

disables at least one of the fuel injectors;

uses an open loop to control fuel delivery by the injectors to the cylinders; and

disables purging of the canister.

12. The system of claim 11 , wherein said control module:

verifies whether the at least one disabled fuel injector corresponds to the misfiring cylinder; and

based on the verifying:

re-enables the at least one disabled fuel injector;

uses a closed loop to control fuel delivery by the injectors to the cylinders; and

re-enables purging of the canister.

13. The system of claim 11 , wherein said control module:

periodically re-enables the at least one disabled injector;

tests whether misfire occurs in a cylinder associated with the at least one re-enabled injector; and

based on the testing:

re-enables the at least one disabled fuel injector;

uses a closed loop to control fuel delivery by the injectors to the cylinders; and

re-enables purging of the canister.

14. The system of claim 11 , wherein said control module:

determines whether the misfire is indicated by a reliable diagnostic; and

based on the determining:

re-enables the at least one disabled fuel injector;

uses a closed loop to control fuel delivery by the injectors to the cylinders; and

re-enables purging of the canister.

15. The system of claim 14 , wherein whether the misfire is indicated by a reliable diagnostic comprises whether said control module has not provided a diagnostic for a predetermined time period.

16. The system of claim 14 , wherein said control module further determines whether the engine is operating within an operating region associated with reduced accuracy of misfire detection.

17. The system of claim 11 , wherein said control module:

determines whether the misfire occurs in a cylinder different from a cylinder indicated by the misfire diagnostic; and

based on the determining:

re-enables the at least one disabled fuel injector;

uses a closed loop to control fuel delivery by the injectors to the cylinders; and

re-enables purging of the canister.

18. A method of controlling engine operation in a vehicle including a plurality of engine cylinders fueled through a plurality of fuel injectors, the vehicle further including a storage canister in which fuel vapor can be collected and which can be purged for delivery of the fuel vapor to the cylinders, said method comprising:

detecting a misfire of at least one of the cylinders;

analyzing at least one of the detected misfire and another misfire; and, based on said analyzing:

disabling at least one of the fuel injectors;

using an open loop to control fuel delivery by the injectors to the cylinders;

disabling purging of the canister;

determining whether the vehicle engine is operating in an operating region associated with inaccurate misfire detection; and

reversing said disabling and using steps based on the determining.

19. The method of claim 18 , wherein detecting a misfire comprises:

periodically re-enabling a disabled injector; and

detecting a subsequent misfire in a cylinder associated with the re-enabled injector.

20. The method of claim 18 , wherein analyzing further comprises determining whether a control module of the vehicle is providing an accurate misfire diagnostic.

21. The method of claim 18 , wherein analyzing further comprises determining whether an engine condition relating to misfire was detected and disappeared.

22. The method of claim 18 , wherein analyzing further comprises evaluating a user demand for engine power from the vehicle, said evaluating performed using at least one of a throttle position sensor and an accelerator pedal position sensor of the vehicle.

Assignments (13)