Method for operating an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10066565-B2
Application number	US-201313966625-A
Country	US
Kind code	B2
Filing date	Aug 14, 2013
Priority date	Aug 17, 2012
Publication date	Sep 4, 2018
Grant date	Sep 4, 2018

Abstract

A method for operating an internal combustion engine, in particular a gas engine having at least two cylinders, includes acquiring a cylinder-specific first cylinder signal (pmax, E) from each cylinder. At least one combustion parameter (Q, Z) of the corresponding cylinder is controlled as a function of the first cylinder signal (pmax, E), and a cylinder-specific reference cylinder value (pmax′, E′) is set for the first cylinder signal (pmax, E) for each cylinder. The at least one combustion parameter (Q, Z) of the cylinder is adjusted as a function of the deviation of the first cylinder signal (pmax, E) from the reference cylinder value (pmax′, E′), and the first cylinder signal (pmax, E) tracks the reference cylinder value (pmax′, E′).

First claim

The invention claimed is:

1. A method of operating an internal combustion engine having at least two cylinders, said method comprising:
acquiring a cylinder-specific first cylinder signal from each of the at least two cylinders via a sensor; and
controlling a combustion parameter of each of the at least two cylinders as a function of the respective cylinder-specific first cylinder signal using a control device;
wherein said controlling comprises setting a cylinder-specific reference cylinder value for the cylinder-specific first cylinder signal for each of the at least two cylinders via the control device such that at least one of NOx emissions and combustion efficiency of the at least two cylinders is identical or similar, and using the control device to adjust the combustion parameter of each of the at least two cylinders as a function of a deviation of the respective cylinder-specific first cylinder signal from a corresponding cylinder-specific reference cylinder value such that the respective cylinder-specific first cylinder signal tracks the corresponding cylinder-specific reference cylinder value.

2. The method according to claim 1 , wherein the cylinder-specific first cylinder signal is at least one of: an internal cylinder pressure signal, a cylinder exhaust temperature signal, a nitrogen oxide emissions signal, and a combustion air ratio signal.

3. The method according to claim 2 , wherein the cylinder-specific first cylinder signal is a maximum internal cylinder pressure of a combustion cycle signal.

4. The method according to claim 1 , wherein the cylinder-specific reference cylinder value comprises a statistical variable of first cylinder signals of all of the at least two cylinders, and comprises a cylinder-specific offset from the statistical variable of the first cylinder signals.

5. The method according to claim 4 , wherein the statistical variable of the first cylinder signals of all of said at least two cylinders is the arithmetic mean value.

6. The method according to claim 4 , wherein the statistical variable of the first cylinder signals of all of said at least two cylinders is the median value.

7. The method according to claim 4 , wherein the cylinder-specific offset is determined by a difference value characteristic mapping, the difference value characteristic mapping accounting for at least one of a power equivalent of an output power of the internal combustion engine and a charge air pressure of the internal combustion engine.

8. The method according to claim 7 , wherein the difference value characteristic mapping further accounts for at least one of a charge air temperature and an engine speed of the internal combustion engine.

9. The method according to claim 4 , wherein the cylinder-specific offset is determined as a function of at least one of: a cylinder pressure during a compression phase before ignition, an air mass equivalent, a center of combustion, a compression ratio, and an ignition delay.

10. The method according to claim 9 , wherein the cylinder-specific offset is determined as a function of at least one deviation of a cylinder parameter from a mean value of the cylinder parameter of all of the at least two cylinders.

11. The method according to claim 10 , wherein the cylinder-specific offset is determined from respective deviations of cylinder parameters using the following formula:
Δ m=a*Δpverd+b *Δair+ c*MFB+d*Δe+e */Δdelay

wherein Δpverd is a deviation of the cylinder pressure during the compression phase before ignition, flair is a deviation of the air mass equivalent, ΔMFB is a deviation in the center of combustion, Δϵ is a deviation in the compression ratio and Δdelay is a deviation in the ignition delay, and a, b, c, d, e are weighting coefficients for the deviations.

12. The method according to claim 1 , wherein the combustion parameter is a fuel quantity for each of the at least two cylinders.

13. The method according to claim 12 , wherein said adjusting of the combustion parameter comprises increasing the fuel quantity for the corresponding cylinder if the respective cylinder-specific first cylinder signal is smaller than the corresponding cylinder-specific reference cylinder value.

14. The method according to claim 12 , wherein said adjusting of the combustion parameter comprises decreasing the fuel quantity for the corresponding cylinder if the respective cylinder-specific first cylinder signal is larger than the corresponding cylinder-specific reference cylinder value.

15. The method according to claim 12 , wherein a fuel metering valve is provided for each of the at least two cylinders, wherein said adjusting of the combustion parameter comprises adjusting an open period for each corresponding fuel metering valve to adjust the fuel quantity for each respective one of the at least two cylinders.

16. The method according to claim 1 , wherein the combustion parameter is an ignition point for each of the at least two cylinders.

17. The method according to claim 16 , wherein said adjusting of the combustion parameter comprises setting the ignition point earlier for a corresponding one of the at least two cylinders if the respective cylinder-specific first cylinder signal is smaller than the corresponding cylinder-specific reference cylinder value.

18. The method according to claim 16 , wherein said adjusting of the combustion parameter comprises setting the ignition point later for a corresponding one of the at least two cylinders if the respective cylinder-specific first cylinder signal is larger than the corresponding cylinder-specific reference cylinder value.

19. The method according to claim 16 , wherein an ignition device is provided for each of the at least two cylinders, wherein the ignition point for the ignition device is set in degrees of crank angle before TDC.

20. The method according to claim 1 , wherein said adjusting the combustion parameter comprises determining a specifiable overall engine target value.

21. The method according to claim 20 , wherein said determining of the specifiable overall engine target value comprises determining the specifiable overall engine target value from a specifiable fuel-air ratio.

22. The method according to claim 21 , wherein the specifiable fuel-air ratio is determined from at least one of a power equivalent of an output power of the internal combustion engine, a charge air pressure, and an engine speed of the internal combustion engine.

23. The method according to claim 21 , wherein the specifiable fuel-air ratio is determined from at least one of an electrical power from a generator connected to the internal combustion engine, a charge air pressure, and an engine speed of the internal combustion engine.

24. The method according to claim 20 , wherein the specifiable overall engine target value is determined as a function of at least one of: (i) a deviation of a power equivalent of an output power of the internal combustion engine from a specifiable target power equivalent, and (ii) a deviation of an engine speed of the internal combustion engine from a specifiable target speed of the internal combustion engine.

25. The method according to claim 1 , wherein said controlling further comprises using the control device to monitor a combustion condition of each of the at least two cylinders, and determine whether the combustion condition is normal or abnormal with respect to a specifiable reference state, and said adjusting compris

Assignees

• Ge Jenbacher Gmbh & Co Og

Inventors

• Barth Christian
• Kopecek Herbert
• Spyra Nikolaus
• Waldhart Michael

Classifications

• F02D41/1486 Primary

  with correction for particular operating conditions · CPC title

• F02D41/401

  Controlling injection timing (F02D41/402 takes precedence) · CPC title

• F02D41/0085

  Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio · CPC title

• F02D41/008 Primary

  Controlling each cylinder individually · CPC title

• F02D35/023

  by determining the cylinder pressure · CPC title