System and method for diagnosing and calibrating internal combustion engines

• US 7,113,861 B2
• Filed: 04/19/2005
• Issued: 09/26/2006
• Est. Priority Date: 05/15/2002
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Jacobson, Evan Earl
• Primary Examiner(s): KWON, JOHN
• Application Number:
  US11/108,650
• Publication Number:
  US 20050187700A1
• Time in Patent Office: 525 Days
• Field of Search: 701/101, 701/103, 701/110, 123/434, 123/435, 123/406.2, 123/406.26, 123/406.28, 123/90.1, 731/16
• US Class Current: 701/101
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 41/1405 Neural network control
• CPC Class Codes: F02D 41/2496 the memory being part of a closed loop

Abstract

A method, system, and machine-readable storage medium for determining a predetermined operating condition of an internal combustion engine are disclosed. In operation, the method, system and machine-readable storage medium measure a cylinder pressure in at least one combustion chamber at a predetermined point in a combustion cycle. Next, the method, system, and machine-readable storage medium determine at least a first value for an operating parameter of the engine using the measured cylinder pressure, determine a second value for the operating parameter of the engine using data received from at least one engine sensor, and then generate a predetermined signal if a difference between the first value and the second value has a predetermined relationship.

Claims

1. A method for determining a predetermined operating condition of an internal combustion engine, the method comprising:

measuring a cylinder pressure in at least one combustion chamber, for at least one cylinder, at a predetermined point in a combustion cycle, the predetermined point in the combustion cycle is during at least one of an exhaust stroke and an intake stroke of the at least one cylinder;

inputting the measured cylinder pressure for the at least one cylinder into a neural network;

determining from the neural network output, whether a predetermined condition exists in at least one cylinder; and

adjusting a component of the at least one cylinder, if an abnormal condition has been detected.

2. The method of claim 1, wherein the adjusted component is valve timing.

3. The method of claim 1, wherein the adjusted component comprises an air-fuel ratio.

4. The method of claim 1, wherein the neural network comprises a back propagation neural network.

5. The method of claim 1, wherein the abnormal condition comprises a cylinder misfire.

6. The method of claim 5, wherein the determining step further comprises:

evaluating at least two pressure outputs from a cylinder;

comparing the output to a previous output pressure from the cylinder; and

determining that the cylinder has misfired, if;

the difference between the current output value and a previous output value has a predetermined relationship; and

the engine has remained in a substantially constant operating condition.

7. The method of claim 6, wherein the determining step includes the step of determining that the cylinder has misfired, if the difference between the current output value and a previous output value exceeds a predetermined amount.

8. The method of claim 1, wherein the abnormal condition comprises a combustion knock.

9. The method of claim 8, wherein the determining step further includes:

evaluating a peak rate of pressure rise from a cylinder; and

determining that a combustion knock has occurred, if the peak rate of pressure rise exceeds a predetermined value.

10. The method of claim 9, wherein the determining step further comprises determining that a combustion knock has occurred, if the difference between a current pressure output value and a previous pressure output value exceeds a predetermined amount.

30. The method of claim 1, wherein the predetermined point occurs when an intake valve and an exhaust valve are open.

31. The method of claim 1, wherein the adjusting of the component of the at least one cylinder includes adjusting at least one of an intake valve and an exhaust valve actuation characteristic.

32. The method of claim 1, wherein the adjusting of the component of the at least one cylinder includes adjusting a turbocharger operation.

11. A machine-readable storage medium having stored thereon machine executable instructions, the execution of said instructions adapted to implement a method for determining a predetermined operating condition of an internal combustion engine, the method comprising:

measuring a cylinder pressure in at least one combustion chamber, for at least one cylinder, at a predetermined point in a combustion cycle;

inputting the measured cylinder pressure for the at least one cylinder into a neural network; and

determining an emissions characteristic from a neural network output.

12. The machine-readable storage medium of claim 11, wherein the predetermined point in a combustion cycle is during at least one stroke of a combustion cycle.

13. The machine-readable storage medium of claim 11, wherein the method for determining the predetermined operating condition further includes:

determining from the neural network output whether a predetermined condition exists in the at least one cylinder;

adjusting a component of the at least one cylinder if an abnormal condition has been detected, and

the adjusted component is valve timing.

14. The machine-readable storage medium of claim 11, wherein the method for determining the predetermined operating condition further includes:

determining from the neural network output whether a predetermined condition exists in the at least one cylinder;

adjusting a component of the at least one cylinder if an abnormal condition has been detected, and

the adjusted component comprises an air-fuel ratio.

15. The machine-readable storage medium of claim 11, wherein the neural network comprises a back propagation neural network.

16. The machine-readable storage medium of claim 11, wherein the method for determining the predetermined operating condition further includes:

determining from the neural network output whether a predetermined condition exists in the at least one cylinder;

adjusting a component of the at least one cylinder if an abnormal condition has been detected, and

the abnormal condition comprises a cylinder misfire.

17. The machine-readable storage medium of claim 16, wherein the determining step further includes;

evaluating a pressure output from a cylinder;

comparing the output to a previous output pressure from the cylinder; and

determining that the cylinder has misfired, if;

the difference between the current output value and a previous output value has a predetermined relationship; and

the engine has remained in a substantially constant operating condition.

18. The machine-readable storage medium of claim 11, wherein the method for determining the predetermined operating condition further includes:

determining from the neural network output whether a predetermined condition exists in the at least one cylinder;

adjusting a component of the at least one cylinder if an abnormal condition has been detected, and

the abnormal condition comprises a combustion knock.

19. The machine-readable storage medium of claim 18, wherein the determining step further includes:

evaluating a peak rate of pressure rise from a cylinder; and

determining that a combustion knock has occurred, if the peak rate of pressure rise exceeds a predetermined amount.

33. The machine-readable storage medium of claim 11, wherein the method for determining the predetermined operating condition further includes calculating an amount of residual gas of the at least one cylinder based on the measured cylinder pressure, and the predicting of the emissions characteristic is based on the calculated amount of residual gas.

20. An apparatus for determining a predetermined operating condition of an internal combustion engine, the apparatus comprising:

a module configured to measure a cylinder pressure in at least one combustion chamber, for at least one cylinder, at a predetermined point in a combustion cycle;

a module configured to determine a heat release profile of the at least one cylinder based on the measured cylinder pressure for the at least one cylinder;

a module configured to input the measured cylinder pressure for the at least one cylinder into a neural network;

a module configured to determine from the neural network output, whether a predetermined condition exists in at least one cylinder; and

a module configured to adjust a component of the at least one cylinder, if an abnormal condition has been detected.

21. The apparatus of claim 20, wherein the predetermined point in a combustion cycle is during at least one stroke of a combustion cycle.

22. The apparatus of claim 20, wherein the adjusted component is valve timing.

23. The apparatus of claim 20, wherein the adjusted component comprises air-fuel ratio.

24. The apparatus of claim 20, wherein the neural network comprises a back propagation neural network.

25. The apparatus of claim 20, wherein the abnormal condition comprises a cylinder misfire.

26. The apparatus of claim 25, wherein the module configured to determine further includes;

a module configured to evaluate a pressure output from a cylinder;

a module configured to compare the output to a previous output pressure from the cylinder; and

a module configured to determine that the cylinder has misfired, if;

the difference between the current output value and a previous output value has a predetermined relationship; and

the engine has remained in a substantially constant operating condition.

27. The apparatus of claim 20, wherein the abnormal condition comprises a combustion knock.

28. The apparatus of claim 27, wherein the module configured to determine further includes:

a module configured to evaluate a pressure output from a cylinder; and

a module configured to determine that a combustion knock has occurred, if a peak rate of pressure rise exceeds a predetermined amount.

29. The apparatus of claim 28, wherein the plurality of modules comprise functionally related computer program code and data.

34. The apparatus of claim 20, further including a module configured to adjust at least one of a timing and duration of an injection phase based on the heat release profile.