Method and system for determining an absolute power loss condition in an internal combustion engine

• US 6,199,007 B1
• Filed: 04/18/2000
• Issued: 03/06/2001
• Est. Priority Date: 07/09/1996
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Schricker, David R., Zavarehi, Masoud K.
• Primary Examiner(s): Yuen, Henry C.
• Assistant Examiner(s): Vo, Hieu T.
• Application Number:
  US09/551,073
• Time in Patent Office: 322 Days
• Field of Search: 701/101, 701/111, 701/110, 701/102, 123/436, 123/478, 123/480, 73/116, 73/117.3, 180/165
• US Class Current: 701/111
• CPC Class Codes: G01M 15/05 by combined monitoring of two or more different engine parameters

Abstract

A method and system for detecting absolute power loss in a cylinder for a reciprocating internal combustion engine, the internal combustion engine having at least one cylinder and a rotatable crankshaft. This method and system includes sensing rotational crankshaft speed for a number of designated crankshaft rotational positions over a predetermined number of cycles of rotation for each of the crankshaft positions and determining an average crankshaft speed fluctuation for each of the crankshaft positions and determining information representative of crankshaft kinetic energy variations due to each firing event or each firing event and compression event in said cylinder and determining information representative of an average fuel flow rate and determining information representative of power loss for the cylinder as a function of the crankshaft kinetic energy variations due to each firing event, the average crankshaft speed and the average fuel flow rate and responsively producing a representative power loss signal and determining information representative of crankshaft torque as a function of the crankshaft kinetic energy variations due to each firing event and compression event and the average crankshaft speed and responsively producing a representative crankshaft torque signal and determining information representative of absolute power loss for each cylinder.

Claims

1. A system for detecting absolute power loss in a cylinder for a reciprocating internal combustion engine, said internal combustion engine having at least one cylinder and a rotatable crankshaft, comprising:

an input mechanism that generates a signal, including a value for rotational crankshaft speed for a plurality of designated crankshaft rotational positions over a predetermined number of cycles of rotation for each of said crankshaft positions; and

an electronic controller for determining an average crankshaft speed and an average crankshaft speed fluctuation for each of said crankshaft positions and determining information representative of crankshaft kinetic energy variations due to each firing event in said cylinder and determining information representative of crankshaft kinetic energy variations due to each firing event and each compression event in said cylinder and determining information representative of an average fuel flow rate and determining information representative of power loss as a function of said crankshaft kinetic energy variations due to each said firing event, said average crankshaft speed and said average fuel flow rate and responsively producing a representative crankshaft power loss signal and determining information representative of crankshaft torque for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event and each said compression event and said average crankshaft speed and responsively producing a representative crankshaft torque signal and determining information representative of absolute power loss for each said cylinder.

2. The system, as set forth in claim 1, wherein said electronic controller determines normalized kinetic energy variations for said cylinder due to each said firing event and each said compression event, wherein information representative of average crankshaft torque is determined as a function of said normalized kinetic energy variations for said cylinder due to each said firing event and said compression event and said average crankshaft speed.

3. The system, as set forth in claim 1, wherein said electronic controller determines information representative of absolute power loss for each said cylinder includes a step of determining information representative of nominal crankshaft torque from a normal engine.

4. The system, as set forth in claim 3, wherein said electronic controller determines information representative of nominal crankshaft torque from a normal engine utilizing a look-up table.

5. The system, as set forth in claim 3, wherein said electronic controller determines information representative of absolute power loss for each said cylinder includes a step of determining a percentage of total torque deficit as the percent difference between said nominal crankshaft torque from said normal engine and said information representative of said crankshaft torque for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event and said compression event and said average crankshaft speed.

6. The system, as set forth in claim 5, wherein said electronic controller determines information representative of absolute power loss for each said cylinder includes a step of determining a percentage of total power loss for all of said cylinders associated with said internal combustion engine by summing information representative of power loss for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event, said average crankshaft speed and said average fuel flow rate and dividing by the total number of said cylinders associated with said internal combustion engine.

7. The system, as set forth in claim 6, wherein said electronic controller determines information representative of absolute power loss for each said cylinder includes a step of determining a percentage of power deficit error for each of said cylinders associated with said internal combustion engine by subtracting said percentage of total power loss for all of said cylinders associated with said internal combustion engine from said percentage of power deficit error for each of said cylinders associated with said internal combustion engine.

8. The system, as set forth in claim 7, wherein said electronic controller determines information representative of absolute power loss for each said cylinder includes a summation of said percentage of power deficit error for each of said cylinders associated with said internal combustion engine and said information representative of power loss for each said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event, said average crankshaft speed and said average fuel flow rate.

9. The system, as set forth in claim 1, wherein said electronic controller responsively produces a representative absolute power loss utilizing a neural network.

10. The system, as set forth in claim 1, wherein said electronic controller produces a representative absolute power loss signal utilizing a radial basis neural network.

11. A method for detecting absolute power loss in a cylinder for a reciprocating internal combustion engine, said internal combustion engine having at least one cylinder and a rotatable crankshaft, comprising the steps of:

sensing rotational crankshaft speed for a plurality of designated crankshaft rotational positions over a predetermined number of cycles of rotation for each of said crankshaft positions;

determining an average crankshaft speed;

determining an average crankshaft speed fluctuation for each of said crankshaft positions;

determining information representative of crankshaft kinetic energy variations due to each firing event in said cylinder;

determining information representative of crankshaft kinetic energy variations due to each firing event and each compression event in said cylinder;

determining information representative of an average fuel flow rate;

determining information representative of power loss for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event, said average crankshaft speed and said average fuel flow rate and responsively producing a representative power loss signal;

determining information representative of crankshaft torque for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event and each said compression event and said average crankshaft speed and responsively producing a representative crankshaft torque signal; and

determining information representative of absolute power loss for each said cylinder.

12. The method, as set forth in claim 11, further including a step of determining normalized kinetic energy variations for said cylinder, wherein said information representative of crankshaft torque for said cylinder is determined as a function of said normalized kinetic energy variations due to each said firing event and each said compression event and said average crankshaft speed.

13. The method, as set forth in claim 11, wherein said step of determining information representative of absolute power loss for each said cylinder includes a step of determining information representative of nominal crankshaft torque from a normal engine.

14. The method, as set forth in claim 13, wherein said step of determining information representative of nominal crankshaft torque from a normal engine includes utilizing a look-up table.

15. The method, as set forth in claim 13, wherein said step of determining information representative of absolute power loss for each said cylinder includes a step of determining a percentage of total torque deficit as a percent difference between said nominal crankshaft torque from said normal engine and said information representative of said crankshaft torque for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event and each said compression event and said average crankshaft speed.

16. The method, as set forth in claim 15, wherein said step of determining information representative of absolute power loss for each said cylinder includes a step of determining a percentage of total power loss for all of said cylinders associated with said internal combustion engine by summing said information representative of power loss for said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event, said average crankshaft speed and said average fuel flow rate and dividing by a total number of said cylinders associated with said internal combustion engine.

17. The method, as set forth in claim 16, wherein said step of determining information representative of absolute power loss for each said cylinder includes a step of determining a percentage of power deficit error for each of said cylinders associated with said internal combustion engine by subtracting said percentage of total power loss for all of said cylinders associated with said internal combustion engine from said percentage of total torque deficit.

18. The method, as set forth in claim 17, wherein said step of determining information representative of absolute power loss for each said cylinder includes a summation of said percentage of power deficit error and said information representative of power loss for each said cylinder as a function of said crankshaft kinetic energy variations due to each said firing event, said average crankshaft speed and said average fuel flow rate for each of said cylinders associated with said internal combustion engine.

19. The method, as set forth in claim 11, wherein said step of responsively producing a representative absolute power loss signal is performed using a neural network.

20. The method, as set forth in claim 11, wherein said step of responsively producing a representative absolute power loss signal is performed using a radial basis neural network.