Misfire detection apparatus for internal combustion engine based on piston speed

• US 20070137289A1
• Filed: 03/28/2006
• Published: 06/21/2007
• Est. Priority Date: 12/20/2005
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: Mathews, David, Assaf, Tameem, St. Pierre, David
• Granted Patent: US 7,353,803 B2
• Time in Patent Office: Days
• US Class Current: 73/114.40
• CPC Class Codes: F02D 2200/1015 Engines misfires
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: G01M 15/11 by detecting misfire

Abstract

The present invention generally includes a method of detecting a misfire in an internal combustion engine. The method includes detecting a first engine speed at a first crankshaft position that corresponds to about a top dead center compression position of a first piston within a first cylinder and detecting a second engine speed at a second crankshaft position that corresponds to about a position subsequent to the top dead center compression position. The method determines whether the misfire occurred in the first cylinder based on the first engine speed and the second engine speed. The method provides an improved signal to noise ratio for engine misfire detection.

Claims

1. A method of detecting a misfire in an engine comprising:

detecting a first engine speed at a first crankshaft position that corresponds to about a top dead center compression position of a first piston within a first cylinder;

detecting a second engine speed at a second crankshaft position that corresponds to about a position subsequent to said top dead center compression position; and

determining whether the misfire occurred in said first cylinder based on said first engine speed and said second engine speed.

2. The method of claim 1 wherein said determining whether the misfire occurred in said first cylinder based on said first engine speed and said second engine speed includes determining a first change in a first piston speed based on a difference between said first engine speed and said second engine speed and determining whether the misfire occurred in said first cylinder based on said first change and detecting the misfire in said first cylinder when a magnitude of said first change is greater than a threshold.

3. The method of claim 1 wherein thirty-degrees of circumferential crankshaft spacing separate said first crankshaft position and said second crankshaft position.

4. The method of claim 3 wherein a second timing tooth corresponds to said second crankshaft position, a first timing tooth corresponds to said first crankshaft position and each of said first timing tooth and said second timing tooth corresponds to six degrees of circumferential crankshaft spacing.

5. The method of claim 4 wherein five timing teeth are disposed between said first timing tooth and second timing tooth.

6. The method of claim 4 further comprising detecting a trailing edge of each timing tooth.

7. The method of claim 1 further comprising detecting a plurality of engine speeds that correspond to respective crankshaft positions.

8. The method of claim 1 further comprising detecting a plurality of engine speeds that correspond to respective timing teeth.

9. The method of claim 1 further comprising detecting a third engine speed at a third crankshaft position that corresponds to about a top dead center compression position of a second piston within a second cylinder.

10. The method of claim 9 wherein said second cylinder is immediately subsequent said first cylinder in a cylinder firing order.

11. The method of claim 9 further comprising determining whether the misfire occurred in said second cylinder when a value of a first derivative based on said first engine speed and said second engine speed is less than a threshold and a second derivative based on said first engine speed, said second engine speed and said third engine speed is less than a threshold.

12. A method of detecting a misfire in an internal combustion engine comprising:

detecting a first engine speed at a first crankshaft position that corresponds to about a top dead center compression position of a first piston within a first cylinder;

detecting a second engine speed at a second crankshaft position that corresponds to about a top dead center compression position of a second piston within a second cylinder;

detecting a third engine speed at a third crankshaft position that corresponds to about a top dead center compression position of a third piston within a third cylinder; and

determining whether the misfire occurred in said second cylinder based on said first engine speed, said second engine speed and said third engine speed.

13. The method claim of claim 12 wherein the misfire occurred in said second cylinder when a change between said third engine speed and said second engine speed is less than a threshold and a second derivative based on said third engine speed, said second engine speed and said first engine speed is less than a threshold.

14. The method claim of claim 12 further comprising detecting a fourth engine speed at a fourth crankshaft position that corresponds to about a top dead center compression position of a fourth piston within a fourth cylinder.

15. The method of claim 14 further comprising determining whether the misfire occurred in said second cylinder based further on said fourth engine speed.

16. The method of claim 14 wherein the misfire occurred in said second cylinder when

a change in said third engine speed and said second engine speed is less than a threshold,

a second derivative based on said third engine speed, said second engine speed and said first engine speed is less than a threshold, and

a second derivative based on said fourth engine speed, said third engine speed and said second engine speed is less than a threshold.

17. A misfire detection system for an internal combustion engine comprising:

a first cylinder having a first piston coupled to a crankshaft, said piston traveling through a plurality of positions, each of said positions corresponding to respective crankshaft positions; and

a control module that detects a first engine speed at a first crankshaft position that corresponds to a top dead center compression position of said first piston within said first cylinder, that detects a second engine speed at a second crankshaft position, that determines a first change in engine speed based on a difference between said first engine speed and said second engine speed, and that determines whether the misfire occurred in said first cylinder based on said first change in said first engine speed.

18. The system of claim 17 wherein said second crankshaft position occurs after said first crankshaft position.

19. The system of claim 17 wherein thirty-degrees of circumferential crankshaft spacing separate said first crankshaft position from said second crankshaft position.

20. The system of claim 17 further comprising a second cylinder having a second piston connected to said crankshaft, said piston traveling through a plurality of positions, each of said positions corresponding to respective crankshaft positions.

21. The system of claim 20 wherein said control module detects a third engine speed at a third crankshaft position that corresponds to said top dead center compression position of said third piston within said third cylinder.

22. The system of claim 21 wherein said control module determines that a misfire occurred in said first cylinder when a change between said second engine speed and said first engine speed is greater than a threshold.

23. The system of claim 21 wherein said control module determines that a misfire occurred in said first cylinder when

a change between said second engine speed and said first engine speed is less than a threshold, and

a change between said third engine speed and said second engine speed is greater than a threshold.

24. A misfire detection system for an internal combustion engine comprising:

a first cylinder having a first piston connected to a crankshaft, said first piston traveling through a plurality of positions, each of said positions corresponding to respective crankshaft positions;

a second cylinder having a second piston connected to said crankshaft, said second piston traveling through a plurality of positions, each of said positions corresponding to respective crankshaft positions;

a third cylinder having a third piston connected to said crankshaft, said third piston traveling through a plurality of positions, each of said positions corresponding to respective crankshaft positions; and

a control module that detects a first engine speed at a first crankshaft position that corresponds to about a top dead center compression position of said first piston within said first cylinder, that detects a second engine speed at a second crankshaft position that corresponds to about a top dead center compression position of said second piston in said second cylinder, that detects a third engine speed at a third crankshaft position that corresponds to about a top dead center compression position of said third piston within said third cylinder and that determines whether a misfire has occurred in said second cylinder based on said first engine speed, said second engine speed and said third engine speed.

25. The system of claim 24 wherein said second cylinder is immediately subsequent said first cylinder in a cylinder firing order.

26. The system of claim 24 wherein said control module determines said misfire occurred in said second cylinder when

a change between said third engine speed and said second engine speed is less than a threshold,

and a value of a second derivative based on a third engine speed, a second engine speed and a first engine speed is less than a threshold.

27. The system of claim 24 further comprising a fourth cylinder having a fourth piston connected to said crankshaft, said fourth piston traveling through a plurality of positions, each of said positions corresponding to respective crankshaft positions and wherein said control module detects a fourth engine speed at a fourth crankshaft position that corresponds to about a top dead center compression position of said fourth piston within said fourth cylinder and determines whether a misfire has occurred in said second cylinder based further on said fourth engine speed.

28. The system claim of claim 27 wherein the misfire occurred in said second cylinder when

a change between said third engine speed and said second engine speed is less than a threshold,

a second derivative based on said third engine speed, said second engine speed and said first engine speed is less than a threshold, and

a second derivative based on said fourth engine speed, said third engine speed and said second engine speed is less than a threshold.