METHOD OF FUEL QUALITY DETERMINATION

• US 20130275021A1
• Filed: 10/10/2012
• Published: 10/17/2013
• Est. Priority Date: 10/10/2011
• Status: Active Grant

• Current Assignee: Phinia Delphi Luxembourg SARL
• Original Assignee: Delphi Technologies Holding S.a.r.l. (Aptiv PLC)
• Inventors: MALACZYNSKI, GERARD WLADYSLAW, VAN DER POEL, ROBERT J.A.
• Granted Patent: US 9,046,048 B2
• Time in Patent Office: Days
• US Class Current: 701/101
• CPC Class Codes: F02B 3/06 with compression ignition compression ignition engines using air or gas for blowing fuel into compressed air in cylinder F02B13/02
• CPC Class Codes: F02D 19/0636 by estimation, i.e. without using direct measurements of a corresponding sensor
• CPC Class Codes: F02D 19/0649 Liquid fuels having different boiling temperatures, volatilities, densities, viscosities, cetane or octane numbers
• CPC Class Codes: F02D 2041/288 for performing a transformation into the frequency domain, e.g. Fourier transformation
• CPC Class Codes: F02D 2200/0612 determined by estimation
• CPC Class Codes: F02D 2200/101 Engine speed
• CPC Class Codes: F02D 2250/14 Timing of measurement, e.g. synchronisation of measurements to the engine cycle
• CPC Class Codes: F02D 41/0025 Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
• CPC Class Codes: F02D 41/08 for idling F02D41/06, F02D41/16 take precedence
• CPC Class Codes: F02D 41/1497 With detection of the mechanical response of the engine
• CPC Class Codes: F02D 45/00 Electrical control not provided for in groups F02D41/00 - F02D43/00
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

A method of determining fuel quality in an internal combustion engine comprises the steps of: a) sampling a signal representative of the revolution speed of said engine during a sampling window, thereby obtaining an array of samples; and b) computing a Fourier component corresponding to a predetermined index in the frequency domain and determining a fuel quality indicator therefrom. The fuel quality indicator is representative of a magnitude of the Fourier component of this predetermined index.

Claims

1. A method of determining fuel quality in an internal combustion engine comprising the steps of:

a) sampling a signal representative of the revolution speed of said engine during a sampling window, thereby obtaining an array of samples;

b) computing a Fourier component corresponding to a predetermined index in the frequency domain and determining a fuel quality indicator therefrom; and

c) deciding on the opportunity of taking corrective measures based on said fuel quality indicator;

wherein said fuel quality indicator is representative of a magnitude of said Fourier component of said predetermined index.

2. The method according to claim 1, wherein the selection of said predetermined index is based on the number of firing events within the sampling window.

3. The method according to claim 2, wherein said predetermined index is defined as the number of firing events per combustion cycle multiplied by the number of combustion cycles in the sampling window.

4. The method according to claim 1, wherein a set of 12 to 20 samples per engine revolution is taken.

5. The method according to claim 4, wherein a set of 15 samples per engine revolution is taken.

6. The method according to claim 1, wherein said engine comprises four cylinders, said sampling window extends over two combustion cycles and said predetermined index is the 8^th index.

7. The method according to claim 1, wherein said engine comprises six cylinders, said sampling window extends over two combustion cycles and said predetermined index is the 12^th index.

8. The method according to claim 1, wherein said method is performed under predetermined engine speed/load conditions.

9. The method according to claim 8, wherein said method is performed when the engine is idling.

10. The method according to claim 1, wherein at least two of said arrays of samples are determined at different engine speed/load conditions, and the respective fuel quality indicators representative of the magnitudes of the Fourier component from said at least two arrays are determined, and a change of fuel quality is taken into account only if the determined fuel quality indicators converge.

11. The method according to claim 1, comprising comparing said fuel quality indicator to a calibrated threshold, which is based on a calibrated magnitude of a complex number of same index obtained with a reference fuel at substantially same engine speed/load.

12. The method according to claim 11 wherein comparison to a single calibration point or threshold, or to a limited number of calibration points or thresholds, is sufficient to detect a change of fuel quality.

13. The method according to claim 1, comprising the further step of attributing the fuel quality indicator to one of at least two fuel classes.

14. The method according to claim 1, wherein said fuel quality indicator is a mean value of fuel quality indicators each representative of a magnitude of said Fourier component of said predetermined index under substantially same engine operating conditions.

15. The method according to claim 1, wherein no corrective measures are taken if a detected variation of said fuel quality indicator does not follow a refueling event.

16. The method according to claim 1, wherein the taking of corrective measures involves adapting engine operating parameters.