FAULT ANALYSIS METHOD AND FAULT ANALYSIS DEVICE FOR AN INTERNAL COMBUSTION ENGINE

• US 20110295485A1
• Filed: 01/27/2010
• Published: 12/01/2011
• Est. Priority Date: 02/04/2009
• Status: Active Grant

• Current Assignee: Vitesco Technologies GmbH (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Afsar Malik, Shahid, Hofmeister, Carl-Eike, Stampfer, Matthias
• Granted Patent: US 9,068,524 B2
• Time in Patent Office: Days
• US Class Current: 701/102
• CPC Class Codes: F02D 41/0085 Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/40 with means for controlling injection timing or duration
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

in a fault analysis method for an internal combustion engine having a plurality of cylinders, an angular speed of the internal combustion engine is determined, and one parameter of the combustion process of one of the plurality of cylinders (6) is adapted in order to equalize the times taken by the internal combustion engine to cover in each case one angle interval. To provide a fault analysis method which makes it possible to detect a defective cylinder (6), it is determined that one of the plurality of cylinders (6) is defective on the basis of the value of the parameter.

Claims

1. A fault analysis method for an internal combustion engine having a plurality of cylinders, comprising:

determining an angular speed of the internal combustion engine, and

adapting a parameter of the combustion process of one of the plurality of cylinders in order to equalize the times in which the internal combustion engine covers in each case one angular interval, wherein, on the basis of the value of the parameter, it is determined that the one of the plurality of cylinders is defective.

2. The fault analysis method according to claim 1, wherein a defect of the one of the plurality of cylinders is identified if the value of the parameter falls below a lower limit, or the value of the parameter exceeds an upper limit.

3. The fault analysis method according to claim 1, wherein further parameters of the other cylinders are adapted in order to keep the internal combustion engine rotational speed constant.

4. The fault analysis method according to claim 3, wherein a defect of the one of the plurality of cylinders is identified if a value of at least one further parameter falls below a lower limit and at the same time an injection quantity is above a lower limit, or if a value of the further parameter exceeds an upper limit and at the same time an injection quantity is below a lower limit.

5. The fault analysis method according to claim 4, wherein injection quantities in in each case one of the plurality of cylinders are calculated from the change in the angular speed of the internal combustion engine.

6. The fault analysis method according to claim 5, wherein, for the calculation of the injection quantities, it is assumed that the change in the angular speed is dependent in each case on a first injection quantity and at least one second injection quantity.

7. The fault analysis method according to claim 6, wherein there is assumed to be a linear relationship between a change in the kinetic energy on account of the change in the angular speed and the first injection quantity, and in that there is assumed to be a linear relationship between the change in the kinetic energy on account of the change in the angular speed and the second injection quantity.

8. The fault analysis method according to claim 2, wherein the parameter is the injection time at which fuel is injected into the one of the plurality of cylinders, and in that the further parameters are the injection time at which fuel is injected into in each case one of the other cylinders.

9. The fault analysis method according to claim 2, wherein the average value of the parameters is compared with an average value of the parameters without adaptation in order to check the result of the fault analysis method.

10. A fault analysis device for an internal combustion engine having a plurality of cylinders, having an angular speed determining device and having an internal combustion engine control device which is configured to adapt a parameter of the combustion process of one of the plurality of cylinders in order to equalize the times in which the internal combustion engine covers in each case one angular interval, wherein the fault analysis device is configured to determine, on the basis of the value of the parameter, that the one of the plurality of cylinders is defective.

11. The fault analysis device according to claim 10, wherein the fault analysis device is set up to identify a defect of the one of the plurality of cylinders if the value of the parameter falls below a lower limit, or if the value of the parameter exceeds an upper limit.

12. The fault analysis device according to claim 11, wherein the fault analysis device is set up to adapt further parameters of the other cylinders in order to keep the internal combustion engine rotational speed constant.

13. The fault analysis device according to claim 12, wherein the fault analysis device is set up to identify a defect of the one of the plurality of cylinders if a value of at least one further parameter falls below a lower limit and at the same time an injection quantity is above a lower limit, or if a value of the further parameter exceeds an upper limit and at the same time an injection quantity is below a lower limit.

14. The fault analysis device according to claim 13, wherein the fault analysis device is set up to calculate injection quantities in in each case one of the plurality of cylinders from the change in the angular speed of the internal combustion engine.

15. The fault analysis device according to claim 11, wherein the fault analysis device is set up to compare the average value of the parameters with an average value of the parameters without adaptation in order to check the result of the fault analysis.

16. An internal combustion engine controller having a fault analysis device for an internal combustion engine having a plurality of cylinders, having an angular speed determining device, wherein the internal combustion engine control device is configured to adapt a parameter of the combustion process of one of the plurality of cylinders in order to equalize the times in which the internal combustion engine covers in each case one angular interval, wherein the fault analysis device is set up to determine, on the basis of the value of the parameter, that the one of the plurality of cylinders is defective.

17. The internal combustion engine controller according to claim 16, wherein the fault analysis device is set up to identify a defect of the one of the plurality of cylinders if the value of the parameter falls below a lower limit, or if the value of the parameter exceeds an upper limit.

18. The internal combustion engine controller according to claim 17, wherein the fault analysis device is set up to adapt further parameters of the other cylinders in order to keep the internal combustion engine rotational speed constant.

19. The internal combustion engine controller according to claim 18, wherein the fault analysis device is set up to identify a defect of the one of the plurality of cylinders if a value of at least one further parameter falls below a lower limit and at the same time an injection quantity is above a lower limit, or if a value of the further parameter exceeds an upper limit and at the same time an injection quantity is below a lower limit.

20. The internal combustion engine controller according to claim 19, wherein the fault analysis device is set up to calculate injection quantities in in each case one of the plurality of cylinders from the change in the angular speed of the internal combustion engine.