SELECTIVE EXHAUST GAS RECIRCULATION DIAGNOSTIC SYSTEMS AND METHODS

• US 20130073179A1
• Filed: 09/21/2011
• Published: 03/21/2013
• Est. Priority Date: 09/21/2011
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Song, B. Jerry, Ramappan, Vijay, Burleigh, Darrell W.
• Granted Patent: US 9,157,390 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F02D 41/0072 Estimating, calculating or determining the EGR rate, amount or flow sensors in EGR systems F02M26/45
• CPC Class Codes: F02D 41/144 Sensor in intake manifold
• CPC Class Codes: F02M 26/49 Detecting, diagnosing or indicating an abnormal function of the EGR system
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A system for a vehicle includes a first exhaust gas flow rate (EGF) estimation module, a second EGF estimation module, and an EGF fault detection module. The first EGF estimation module estimates a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold. The second EGF estimation module estimates a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load. The EGF fault detection module selectively indicates a fault is present in an exhaust gas recirculation (EGR) system based on the first flow rate and the second flow rate.

Claims

1. A system for a vehicle, comprising:

a first exhaust gas flow rate (EGF) estimation module that estimates a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold;

a second EGF estimation module that estimates a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load; and

an EGF fault detection module selectively indicates that a fault is present in an exhaust gas recirculation (EGR) system based on the first flow rate and the second flow rate.

2. The system of claim 1 wherein the second EGF estimates module estimates the second flow rate further based on an opening of an EGR valve.

3. The system of claim 1 wherein the fault indicates at least one of a faulty intake oxygen (IO) sensor, a faulty exhaust oxygen (EO) sensor, a faulty engine speed sensor, an EGR valve opening differently than intended, and pulsating exhaust flow.

4. The system of claim 1 wherein the EGF fault detection module selectively disables the indication based on a change in the engine speed and a change in the engine load.

5. A system for a vehicle, comprising:

a first exhaust gas flow rate (EGF) estimation module that estimates a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold; and

an EGF fault detection module that selectively indicates that a leak is present in an exhaust gas recirculation (EGR) valve based on the first flow rate.

6. The system of claim 5 wherein, when the EGR valve is closed, the EGF fault detection module selectively indicates that the leak is present based on a difference between the first flow rate and a predetermined flow rate.

7. The system of claim 6 wherein the EGF fault detection module indicates that the leak is present when the difference is greater than a predetermined value.

8. The system of claim 5 further comprising a second EGF estimation module that estimates a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load.

9. The system of claim 8 wherein, when the EGR valve is open, the EGF fault detection module selectively indicates that the leak is present based on a difference between the first flow rate and the second flow rate.

10. The system of claim 9 wherein the EGF fault detection module indicates that the leak is present when the difference is greater than a predetermined value.

11. A method comprising:

estimating a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold;

estimating a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load; and

selectively indicating that a fault is present in an exhaust gas recirculation (EGR) system based on the first flow rate and the second flow rate.

12. The method of claim 11 wherein estimating the second flow rate is further based on an opening of an EGR valve.

13. The method of claim 11 wherein the fault indicates at least one of a faulty intake oxygen (IO) sensor, a faulty exhaust oxygen (EO) sensor, a faulty engine speed sensor, an EGR valve opening differently than intended, and pulsating exhaust flow.

14. The method of claim 11 further comprising of selectively disabling the indication based on a change in the engine speed and a change in the engine load.

15. A method comprising:

estimating a first flow rate of exhaust re-circulated back to an intake manifold based on a concentration of oxygen in the intake manifold; and

selectively indicating that a leak is present in an exhaust gas recirculation (EGR) valve based on the first flow rate.

16. The method of claim 15 wherein, when the EGR valve is closed, selectively indicating that the leak is present based on a difference between the first flow rate and a predetermined flow rate.

17. The method of claim 16 further comprising indicating that the leak is present when the difference is greater than a predetermined value.

18. The method of claim 15 further comprising estimating a second flow rate of exhaust re-circulated back to the intake manifold based on an engine speed and an engine load.

19. The method of claim 18 wherein, when the EGR valve is open, selectively indicating that the leak is present is based on a difference between the first flow rate and the second flow rate.

20. The method of claim 19 further comprising indicating that the leak is present when the difference is greater than a predetermined value.