METHOD FOR OPERATING AN INTERNAL COMBUSTION ENGINE

• US 20140052363A1
• Filed: 08/14/2013
• Published: 02/20/2014
• Est. Priority Date: 08/17/2012
• Status: Active Grant

• Current Assignee: INNIO Jenbacher GmbH & Co.,OG.
• Original Assignee: GE Jenbacher GmbH & Company OHG (General Electric Company)
• Inventors: KOPECEK, Herbert, BARTH, Christian, SPYRA, Nikolaus, WALDHART, Michael
• Granted Patent: US 10,066,565 B2
• Time in Patent Office: Days
• US Class Current: 701/111
• CPC Class Codes: F02D 19/024 by controlling fuel injectors
• CPC Class Codes: F02D 29/06 peculiar to engines driving electric generators
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/025 by determining temperatures inside the cylinder, e.g. combustion temperatures
• CPC Class Codes: F02D 37/02 one of the functions being ignition
• CPC Class Codes: F02D 41/0027 the fuel being gaseous non-electrical control F02D19/02
• CPC Class Codes: F02D 41/008 Controlling each cylinder individually
• CPC Class Codes: F02D 41/0085 Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/1486 with correction for particular operating conditions
• CPC Class Codes: F02D 41/401 Controlling injection timing F02D41/402 takes precedence
• CPC Class Codes: F02M 21/0278 Port fuel injectors for single or multipoint injection into the air intake system
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

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 (p_max, 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 (p_max, E), and a cylinder-specific reference cylinder value (p_max′, E′) is set for the first cylinder signal (p_max, 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 (p_max, E) from the reference cylinder value (p_max′, E′), and the first cylinder signal (p_max, E) tracks the reference cylinder value (p_max′, E′).

Claims

1. A method for operating an internal combustion engine, in particular a gas engine, having at least two cylinders, wherein a cylinder-specific first cylinder signal (p_max, E) is acquired from each cylinder, wherein at least one combustion parameter (Q, Z) of the corresponding cylinder is controlled as a function of the first cylinder signal (p_max, E), characterized in that a cylinder-specific reference cylinder value (p_max′

, E′

) is set for the first cylinder signal (p_max, E) for each cylinder, wherein the at least one combustion parameter (Q, Z) of the cylinder is adjusted as a function of the deviation of the first cylinder signal (p_max, E) from the reference cylinder value (p_max′

, E′

), wherein the first cylinder signal (p_max, E) tracks the reference cylinder value (p_max′

, E′

).

2. A method according to claim 1, characterized in that at least one of the following cylinder-specific first cylinder signals is acquired from each cylinder:

internal cylinder pressure (p_cyl), cylinder exhaust temperature (T_E), nitrogen oxide emissions (E) and combustion air ratio.

3. A method according to claim 2, characterized in that a maximum internal cylinder pressure (p_max) of a combustion cycle is acquired as the cylinder-specific first cylinder signal.

4. A method according to claim 1, characterized in that the cylinder-specific reference cylinder value (p_max′

, E′

) comprises a statistical variable of the first cylinder signals (p_max, E) of all cylinders, preferably the arithmetic mean (p_mean), particular preferably the median (E_median), and comprises a cylinder-specific offset (Δ

m).

5. A method according to claim 4, characterized in that the cylinder-specific offset (Δ

m) is determined by means of a difference value characteristic mapping, wherein the difference value characteristic mapping takes into account at least a power equivalent (P) of the output power of the internal combustion engine and/or a charge air pressure (p_A) of the internal combustion engine, preferably in addition a charge air temperature (T_A) and/or an engine speed (n) of the internal combustion engine.

6. A method according to claim 4, characterized in that the cylinder-specific offset (Δ

m) is determined as a function of at least one of the following cylinder-specific cylinder parameters;

cylinder pressure during the compression phase before ignition, air mass equivalent, centre of combustion, compression ratio, ignition delay.

7. A method according to claim 6, characterized in that the cylinder-specific offset (Δ

m) is determined as a function of at least one deviation (Δ

pverd, Δ

air, Δ

MFB, Δ

ε

, Δ

delay) of a cylinder parameter from a mean of the cylinder parameter of all cylinders.

8. A method according to claim 7, characterized in that the cylinder-specific offset (Δ

m) is determined from the respective deviations (Δ

pverd, Δ

air, Δ

MFB, Δ

ε

, Δ

delay) of the cylinder parameters using the following formula;

Δ

m=a*Δ

pverd+b*Δ

air+c*Δ

MFB+d*Δ

ε

+e*Δ

delay

wherein Δ

pverd is the deviation of the cylinder pressure during the compression phase before ignition, Δ

air is the deviation of the air mass equivalent, Δ

MFB is the deviation in the centre of combustion, Δ

ε

is the deviation in the compression ratio and Δ

delay is the deviation in the ignition delay, and wherein a, b, c, d, e are weighting coefficients for the deviations.

9. A method according to claim 1, characterized in that a fuel quantity (Q) for the corresponding cylinder is used as the combustion parameter.

10. A method according to claim 9, characterized in that the fuel quantity (Q) for a cylinder is increased if the cylinder-specific first cylinder signal (p_max, E) is smaller than the cylinder-specific reference cylinder value (p_max′

, E′

).

11. A method according to claim 9, characterized in that the fuel quantity (Q) for a cylinder is decreased if the cylinder-specific first cylinder signal (p_max, E) is larger than the cylinder-specific reference cylinder value (p_max′

, E′

).

12. A method according to claim 9, characterized in that a fuel metering valve is provided for each cylinder, wherein in order to adjust the fuel quantity (Q) for a cylinder, the open period (t_cyl) for the corresponding fuel metering valve is adjusted.

13. A method according to claim 1, characterized in that an ignition point (Z) for the corresponding cylinder is adjusted as the combustion parameter.

14. A method according to claim 13, characterized in that the ignition point (Z) for a cylinder is set earlier if the cylinder-specific first cylinder signal (p_max, E) is smaller than the cylinder-specific reference cylinder value (p_max′

, E′

).

15. A method according to claim 13, characterized in that the ignition point (Z) for a cylinder is set later if the cylinder-specific first cylinder signal (p_max, E) is larger than the cylinder-specific reference cylinder value (p_max′

, E′

).

16. A method according to claim 13, characterized in that an ignition device is provided for each cylinder, wherein the ignition point (Z) for the ignition device is set in degrees of crank angle before TDC (t_cyl).

17. A method according to claim 1, characterized in that, in order to set the at least one combustion parameter (Q, Z), a parameter (t_cyl) is determined wherein preferably, the parameter (t_cyl) comprises a specifiable overall engine target value (t_g).

18. A method according to claim 17, characterized in that the specifiable target value (t_g) is determined from a specifiable fuel-air ratio (λ

), wherein preferably, the specifiable fuel-air ratio (λ

) is determined from a power equivalent (P) of the output power of the internal combustion engine, preferably electrical power from a generator connected to the internal combustion engine, and/or from a charge air pressure (p_A) and/or from an engine speed (n) of the internal combustion engine.

19. A method according to claim 17, characterized in that the specifiable target value (t_g) is determined as a function of the deviation of a power equivalent (P) of the output power of the internal combustion engine from a specifiable target power equivalent (P_S) and/or as a function of the deviation of an engine speed (n) of the internal combustion engine from a specifiable target speed (n_S) of the internal combustion engine.

20. A method according to claim 1, characterized in that a combustion condition is monitored for each cylinder and is evaluated as being normal or abnormal with respect to a specifiable reference state, wherein the combustion parameter (Q, Z) of a cylinder is only adjusted if the combustion condition of the cylinder is evaluated as being normal.

21. A method according to claim 20, characterized in that knocking and/or auto-ignition and/or interruptions in combustion are monitored as the combustion condition, wherein the combustion condition of a cylinder is evaluated as being normal if no knocking and/or no auto-ignition and/or no interruptions in the combustion are discerned.