Method for adjusting an injection behavior of injectors in an internal combustion engine, engine control unit and system for adjusting an injection behavior

• US 9,664,134 B2
• Filed: 04/10/2015
• Issued: 05/30/2017
• Est. Priority Date: 10/10/2012
• Status: Active Grant

• Current Assignee: MTU Friedrichshafen GmbH (Rolls-Royce Holdings Plc)
• Original Assignee: MTU Friedrichshafen GmbH (Rolls-Royce Holdings Plc)
• Inventors: Remele, Jrg, Toth, Aron
• Primary Examiner(s): Solis, Erick
• Application Number:
  US14/683,636
• Publication Number:
  US 20150211430A1
• Time in Patent Office: 781 Days
• Field of Search: 123436, 123673, 123674, 7311448
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 41/0085 Balancing of cylinder outputs, e.g. speed, torque or air-fuel ratio
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/009 using means for generating position or synchronisation signals
• CPC Class Codes: F02D 41/04 Introducing corrections for particular operating conditions F02D41/14 takes precedence
• CPC Class Codes: F02D 41/2438 Active learning methods
• CPC Class Codes: F02D 41/2467 for injectors
• CPC Class Codes: F02D 41/263 the program execution being modifiable by physical parameters
• CPC Class Codes: F02D 41/30 Controlling fuel injection F02D41/182, F02D41/24 take precedence
• CPC Class Codes: F02M 65/001 Measuring fuel delivery of a fuel injector

Abstract

The invention relates to a method for adjusting an injection behavior of injectors in an internal combustion engine, including the following steps: switching off an injector; detecting a crank angle signal of the internal combustion engine; transforming the crank angle signal into the frequency range by way of a discrete Fourier transformation; detecting and storing a quantity of the harmonic of the 0.5th order of the Fourier transform of the crank angle signal, and assigning the quantity to the switched-off injector; switching on the switched-off injector; performing the previous steps sequentially for all injectors of the internal combustion engine; forming an average value of the stored quantities with respect to all injectors, and correcting the control of the injectors using a deviation from the average value of a quantity associated with an injector that is to be corrected.

Claims

1. A method for adjusting an injection behavior of injectors in an internal combustion engine, including the steps of:

turning off one injector;

capturing a crank angle signal of the internal combustion engine;

transforming said crank angle signal into a frequency range by way of a discrete Fourier transformation;

capturing and storing an amount of a harmonic of the 0.5^th order of said Fourier transformation of said crank angle signal;

assigning said amount to said turned off injector;

turning on said turned off injector;

performing the previous steps in a sequential manner for each injector of the internal combustion engine;

creating a mean value of said stored amounts assigned to said injectors; and

correcting a control of each said injector based on a deviation of said amount assigned to each said injector from said mean value.

2. The method according to claim 1, wherein:

said control is corrected for each said injector only if said deviation exceeds a predetermined threshold value.

3. The method according to claim 1, further including the steps of:

calculating for each said injector a differential amount as a difference between said amount of said harmonic of the 0.5^th order of said Fourier transformation of said crank angle signal captured when said injector is turned off and an amount which is detected and stored when all said injectors are turned on; and

using said differential amounts as a basis for creating said mean value and as a basis for said correction.

4. The method according to claim 3, wherein:

said correction step includes adjusting an energizing duration of each said injector.

5. The method according to claim 4, wherein:

said adjustment of said energizing duration for each said injector includes an energizing duration differential being added to a current energizing duration, said energizing duration differential being calculated according to the following formula;

Δ

BD[i]=(MW−

Δ

amount[i])*K;

Δ

BD[i] signifying said energizing duration differential to be added to said current energizing duration for an injector i;

MW representing said mean value calculated from said differential amounts of said amounts of the harmonic of the 0.5^th order assigned to said injectors;

Δ

amount[i] representing said determined differential amount for said injector i; and

K being a constant.

6. The method according to claim 5, wherein:

said formula being used under condition Σ

Δ

BD[i]=0.

7. The method according to claim 6, wherein:

said constant K being selected dependent upon a current actual load point of the internal combustion engine.

8. The method according to claim 1, wherein:

at least two iterations of the method are performed; and

the method is iterated until said deviation for each said injector no longer exceeds a predetermined threshold value.

9. The method according to claim 1, wherein:

said correction step includes compensating said injectors for the correction of each said injector, so that a measure of performance of the internal combustion engine is not changed due to said correction.

10. An engine control unit for an internal combustion engine, said engine control unit implementing a series of steps, said series of steps comprising:

turning off an injector of said internal combustion engine;

capturing a crank angle signal of said internal combustion engine;

transforming said crank angle signal into a frequency range by way of a discrete Fourier transformation;

capturing and storing an amount of a harmonic of the 0.5^th order of said Fourier transformation of said crank angle signal;

assigning said amount to said turned off injector;

turning on said turned off injector;

performing the previous steps in a sequential manner for each injector of the internal combustion engine;

creating a mean value of said stored amounts assigned to said injectors; and

correcting a control of each said injector based on a deviation of said amount assigned to each said injector from said mean value.

11. A system for adjusting an injection behavior of injectors in an internal combustion engine, comprising:

a switching device designed to selectively turn on and turn off an injector;

a detection device designed to capture a crank angle signal of the internal combustion engine;

a converter designed to transform said crank angle signal into a frequency range by way of discrete Fourier transformation;

a memory device designed to capture and store an amount of the harmonic of the 0.05^th order of said Fourier transformation of said crank angle signal, and to assign said amount to said injector;

an averaging element designed to calculate a mean value over said amounts from all said injectors as stored in said memory device; and

a correction element designed to calculate a deviation from said mean value of said amount assigned to an injector that is to be corrected, and to correct a control of said injector based on said calculated deviation.