Fuel system diagnostics by analyzing engine crankshaft speed signal

• US 7,832,259 B2
• Filed: 06/16/2008
• Issued: 11/16/2010
• Est. Priority Date: 06/16/2008
• Status: Expired due to Fees

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (General Motors Company)
• Inventors: Kweon, Chol-Bum M, Haskara, Ibrahim, Wang, Yue-Yun, Matekunas, Frederic Anton, Battiston, Paul Anthony
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US12/139,782
• Publication Number:
  US 20090312932A1
• Time in Patent Office: 883 Days
• Field of Search: 731/140.2, 731/140.4, 731/140.5, 731/142.4, 731/142.5, 731/142.6, 731/142.7, 731/142.8
• US Class Current: 73/114.25
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 35/024 using an estimation
• CPC Class Codes: F02D 35/028 by determining the combustion timing or phasing
• CPC Class Codes: F02D 41/0047 Controlling exhaust gas recirculation [EGR] temperature control with cooler in recirculation circuit F02M26/33
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02D 41/1498 measuring engine roughness

Abstract

Combustion within an internal combustion engine is diagnosed and includes monitoring crankshaft angular velocity and generating a combustion phasing value for a combustion chamber based on the crankshaft angular velocity. The combustion phasing value is compared to an expected combustion phasing value based on a predetermined start of injection crank angle and combustion phasing differences greater than an allowable combustion phasing difference are identified based on the comparison.

Claims

1. A method for diagnosing combustion within an internal combustion engine including a crankshaft and a plurality of combustion chambers, comprising:

monitoring crankshaft angular velocity;

generating a combustion phasing value for a combustion chamber based on said crankshaft angular velocity;

comparing said combustion phasing value to an expected combustion phasing value based on a predetermined start of injection crank angle; and

identifying combustion phasing differences greater than an allowable combustion phasing difference based on said comparing.

2. The method of claim 1, wherein generating a combustion phasing value comprises a Fast Fourier Transform of said crankshaft angular velocity.

3. The method of claim 2, wherein generating a combustion phasing value comprises employing said Fast Fourier Transform to identify a waveform including a first harmonic waveform associated with a combustion cycle.

4. The method of claim 1, wherein said monitoring crankshaft angular velocity comprises monitoring crankshaft angular velocity during engine idle conditions.

5. The method of claim 1, wherein said monitoring crankshaft angular velocity comprises monitoring crankshaft angular velocity during steady average engine speed conditions.

6. The method of claim 5, wherein monitoring crankshaft angular velocity during steady average engine speed conditions comprises monitoring crankshaft angular velocity at a test interval and validating said test interval as steady average engine speed conditions.

7. A method for diagnosing combustion within an internal combustion engine including a crankshaft and a plurality of combustion chambers, comprising:

monitoring crankshaft angular velocity;

generating a combustion phasing value for a combustion chamber based on said crankshaft angular velocity;

estimating a start of injection crank angle based on said combustion phasing value;

comparing said start of injection crank angle to a predetermined start of injection crank angle; and

identifying start of injection crank angle differences greater than an allowable start of injection crank angle difference based on said comparing.

8. The method of claim 7, wherein generating a combustion phasing value for a combustion chamber based on said crankshaft angular velocity comprises utilizing a Fast Fourier Transform to identify a waveform comprising a first harmonic waveform associated with a combustion cycle.

9. The method of claim 7, wherein said monitoring crankshaft angular velocity comprises monitoring crankshaft angular velocity during engine idle conditions.

10. The method of claim 7, wherein said monitoring crankshaft angular velocity comprises monitoring crankshaft angular velocity during steady average engine speed conditions.

11. An apparatus for diagnosing combustion within an engine comprising:

an engine including a variable volume combustion chamber defined by a piston reciprocating within a cylinder between top-dead-center and bottom-dead-center points and a cylinder head;

an engine speed sensor generating engine speed data comprising crankshaft angular velocity; and

a control module configured for

monitoring said engine speed data,

generating a combustion phasing value for said cylinder based on said engine speed data,

comparing said combustion phasing value to an expected combustion phasing value based on a predetermined start of injection crank angle, and

identifying combustion phasing value differences greater than an allowable combustion phasing value difference based on said comparing.

12. The apparatus of claim 11, wherein said engine comprises a direct-injection engine operative lean of stoichiometry.

13. The apparatus of claim 11, wherein said control module utilizes a Fast Fourier Transform of said engine speed data to generate said measured combustion phasing value.

14. The apparatus of claim 13, wherein said Fast Fourier Transform operates upon said engine speed data to identify a waveform comprising a first harmonic waveform associated with a combustion cycle.

15. The apparatus of claim 11, wherein said control module monitoring said engine speed data comprises analyzing said engine speed data to identify an interval of idle operation.

16. The apparatus of claim 11, wherein said control module monitoring said engine speed data comprises analyzing said engine speed data to identify an interval of steady average engine speed conditions.