Device and method for cylinder-torque equalization of an internal combustion engine, computer program, computer program product

• US 8,505,367 B2
• Filed: 12/17/2009
• Issued: 08/13/2013
• Est. Priority Date: 01/09/2009
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Porten, Guido, Chen, Lu, Schott, Marc
• Primary Examiner(s): Kirkland, III, Freddie
• Application Number:
  US13/141,627
• Publication Number:
  US 20110302999A1
• Time in Patent Office: 1,335 Days
• Field of Search: 731/143.1
• US Class Current: 73/114.31
• CPC Class Codes: F02D 41/0085 Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02D 41/3076 with special conditions for selecting a mode of combustion, e.g. for starting, for diagnosing
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A device, a method, a computer program and a computer program product for diagnosing an internal combustion engine (100), in which a first cylinder (102) includes a combustion chamber (101), a fuel quantity and a fresh air quantity being supplied to the combustion chamber (101) for combustion; a torque contribution (D), generated by the combustion, of the first cylinder (102) in a first operating mode (B1) of the internal combustion engine (100) being a function of the fresh air quantity supplied, and in a second operating mode (B2) of the internal combustion engine (100) being essentially a function of the fuel quantity, wherein a first variable (L1) characterizing a smooth running of the internal combustion engine (100) in the first operating mode (B1) is ascertained, a second variable (L2) characterizing the smooth running of the internal combustion engine (100) in the second operating mode is ascertained, the first variable (L1) is compared to the second variable (L2), a diagnosis of the internal combustion engine (100) is made as a function of the result of the comparison.

Claims

1. A method for diagnosing an internal combustion engine, in which a cylinder includes a combustion chamber, a fuel quantity and a fresh air quantity being supplied to the combustion chamber for the combustion to generate a torque contribution of the cylinder, which torque contribution is, in a first operating mode of the internal combustion engine, essentially a function of the fresh air quantity supplied, and, in a second operating mode of the internal combustion engine, essentially a function of the fuel quantity supplied, the method comprising:

ascertaining a first variable characterizing a smooth running of the internal combustion engine in the first operating mode;

ascertaining a second variable characterizing the smooth running of the internal combustion engine in the second operating mode

comparing the first variable to the second variable

diagnosing the internal combustion engine as a function of the result of the comparison; and

recognizing an erroneously supplied fresh air quantity if a third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is greater than a specified value.

2. The method as recited in claim 1, wherein the first variable and the second variable are ascertained at least partially during a power stroke of the cylinder.

3. The method as recited in claim 2, wherein, in the first operating mode, a first fuel quantity is injected;

and, in the second operating mode, a second fuel quantity and a third fuel quantity are injected.

4. The method as recited in claim 2, wherein the second fuel quantity is determined in the second operating mode so that a lean mixture is created.

5. The method as recited in claim 2, wherein a correction of the supplied fuel quantity takes place if the third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is less than or equal to a specified threshold.

6. The method as recited in claim 5, wherein a value for the correction is ascertained in the second operating mode.

7. The method as recited in claim 1, wherein, in the first operating mode, a first fuel quantity is injected;

and, in the second operating mode, a second fuel quantity and a third fuel quantity are injected.

8. The method as recited in claim 7, wherein the second fuel quantity is determined in the second operating mode so that a lean mixture is created.

9. The method as recited in claim 7, wherein the third fuel quantity is determined so that the lambda value of the exhaust gas is essentially one.

10. The method as recited in claim 7, wherein a correction of the supplied fuel quantity takes place if the third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is less than or equal to a specified threshold.

11. The method as recited in claim 10, wherein value for the correction is ascertained in the second operating mode.

12. The method as recited in claim 1, wherein the second fuel quantity is determined in the second operating mode so that a lean mixture is created.

13. The method as recited in claim 12, wherein a correction of the supplied fuel quantity takes place if the third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is less than or equal to a specified threshold.

14. The method as recited in claim 13, wherein the ascertainment of a correction value of the fuel quantity supplied takes place in the second operating mode.

15. The method as recited in claim 1, wherein a correction of the supplied fuel quantity takes place if the third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is less than or equal to a specified threshold.

16. The method as recited in claim 15, wherein a value for the correction is ascertained in the second operating mode.

17. An apparatus for diagnosing an internal combustion engine, in which a cylinder includes a combustion chamber, a fuel quantity and a fresh air quantity being supplied to the combustion chamber for combustion to generate a torque contribution of the cylinder, which torque contribution is, in a first operating mode of the internal combustion engine, essentially a function of the fresh air quantity supplied, and, in a second operating mode of the internal combustion engine, essentially a function of the fuel quantity supplied, the apparatus comprising:

a first ascertainment device which is configured to ascertain a first variable characterizing the smooth running of the internal combustion engine in the first operating mode;

a second ascertainment device which is configured to ascertain a second variable characterizing the smooth running of the internal combustion engine in the second operating mode;

a comparator device which is configured to compare the first variable to the second variable; and

a calculating device which is configured to diagnose the internal combustion engine as a function of the result of the comparison, wherein an erroneously supplied fresh air quantity is recognized if a third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is greater than a specified value.

18. A non-transitory computer-readable data storage medium on which are stored instructions that are executable on a computer, and which, when executed on the computer, performs a method for diagnosing an internal combustion engine, in which a cylinder includes a combustion chamber, a fuel quantity and a fresh air quantity being supplied to the combustion chamber for the combustion to generate a torque contribution of the cylinder, which torque contribution is, in a first operating mode of the internal combustion engine, essentially a function of the fresh air quantity supplied, and, in a second operating mode of the internal combustion engine essentially a function of the fuel quantity supplied, the method comprising:

ascertaining a first variable characterizing a smooth running of the internal combustion engine in the first operating mode

ascertaining a second variable, characterizing the smooth running of the internal combustion engine in the second operating mode;

comparing the first variable to the second variable;

diagnosing of the internal combustion engine as a function of the result of the comparison; and

recognizing an erroneously supplied fresh air quantity if a third variable, that is a function of the absolute amount of the difference between the first variable and the second variable, is greater than a specified value.