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EP1226355A1 - Method and device for the diagnosis of a fuel supply system - Google Patents

Method and device for the diagnosis of a fuel supply system

Info

Publication number
EP1226355A1
EP1226355A1 EP00984821A EP00984821A EP1226355A1 EP 1226355 A1 EP1226355 A1 EP 1226355A1 EP 00984821 A EP00984821 A EP 00984821A EP 00984821 A EP00984821 A EP 00984821A EP 1226355 A1 EP1226355 A1 EP 1226355A1
Authority
EP
European Patent Office
Prior art keywords
fuel
supply system
fuel supply
frequency
frequency spectrum
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP00984821A
Other languages
German (de)
French (fr)
Other versions
EP1226355B1 (en
Inventor
Thomas Frenz
Hansjoerg Bochum
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1226355A1 publication Critical patent/EP1226355A1/en
Application granted granted Critical
Publication of EP1226355B1 publication Critical patent/EP1226355B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/30—Controlling fuel injection
    • F02D41/38—Controlling fuel injection of the high pressure type
    • F02D41/3809—Common rail control systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
    • F02M65/00—Testing fuel-injection apparatus, e.g. testing injection timing ; Cleaning of fuel-injection apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • F02D2041/1413—Controller structures or design
    • F02D2041/1432—Controller structures or design the system including a filter, e.g. a low pass or high pass filter
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/14—Introducing closed-loop corrections
    • F02D41/1401—Introducing closed-loop corrections characterised by the control or regulation method
    • F02D2041/1433—Introducing closed-loop corrections characterised by the control or regulation method using a model or simulation of the system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/22—Safety or indicating devices for abnormal conditions
    • F02D2041/224—Diagnosis of the fuel system
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
    • F02D41/28—Interface circuits
    • F02D2041/286—Interface circuits comprising means for signal processing
    • F02D2041/288—Interface circuits comprising means for signal processing for performing a transformation into the frequency domain, e.g. Fourier transformation
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/06—Fuel or fuel supply system parameters
    • F02D2200/0602—Fuel pressure
    • F02D2200/0604—Estimation of fuel pressure

Definitions

  • the present invention relates to a method and a
  • a fuel supply system of an internal combustion engine is used to deliver fuel from an internal combustion engine
  • Feed fuel tank The fuel is pumped from a fuel pump from the fuel tank via a pressure line to a fuel distributor on the internal combustion engine with injection valves.
  • a pressure sensor is usually arranged on the fuel distributor or elsewhere in the fuel supply system.
  • the fuel pressure in the fuel supply system is measured by the pressure sensor and forwarded to a control system.
  • the control keeps the pressure in the fuel supply system, in particular in the fuel rail, at a predetermined value.
  • the amount of fuel not required by the internal combustion engine is usually fed from the fuel distributor via a return line back into the fuel tank.
  • the fuel supply system can be used as a high-pressure fuel supply system, in particular as a common Rail memory injection system for a direct-injection internal combustion engine, in which a high-pressure fuel reservoir is provided as a fuel distributor.
  • a high-pressure fuel reservoir is provided as a fuel distributor.
  • fuel is drawn from the fuel tank by an as
  • Electric fuel pump designed pre-feed pumps are first fed to a downstream high-pressure feed pump.
  • the high-pressure feed pump then delivers the fuel at a very high pressure into the high-pressure fuel tank, from where it is designed as injectors
  • Injection valves get into a combustion chamber of the internal combustion engine.
  • Pressure sensors are arranged in the high-pressure fuel reservoir in order to measure the fuel pressure in the high-pressure fuel reservoir for regulating the fuel pressure.
  • Fuel supply system is known, for example, from DE 195 39 885 AI.
  • a defective fuel pump can lead to the fact that the required fuel pressure in the fuel supply system can no longer be reached, and so it can be found in certain operating points
  • the invention proposes starting from the method for diagnosing a
  • the fuel supply system can be determined, for example, using ⁇ in ⁇ s physical model of the fuel supply system. For this purpose, state variables of the fuel supply system and / or the internal combustion engine are supplied to the physical model, from which the course of the fuel supply system.
  • Fuel pressure is modeled.
  • the fuel pressure in the fuel supply system is, however, advantageously measured by means of a pressure sensor.
  • a pressure sensor is usually already present in the fuel supply system for detecting the fuel pressure for regulating the fuel pressure in the fuel supply system and can also be used to record the fuel pressure curve in accordance with the present invention.
  • the frequency spectrum is advantageously formed by means of a Fourier transformation of the fuel pressure curve.
  • the fuel pump in the fuel supply system results in a characteristic frequency spectrum of the fuel pressure curve.
  • the frequency spectrum is analyzed for a differentiated diagnosis of a fault in the fuel supply system.
  • Fuel supply system a course characteristic of the respective fuel supply system.
  • the frequency spectrum is compared, for example, with threshold values.
  • An increase or decrease in the amplitude of the frequency spectrum can be caused by ⁇ in ⁇ n
  • the analysis of the frequency spectrum comprises the following steps: Comparing the course of the recorded frequency spectrum with the course of the frequency spectrum of a fuel supply system operating without errors, ⁇ and
  • Fuel supply system and in multi-cylinder fuel pumps, a fault in one of the pump cylinders can be diagnosed from the course of the recorded frequency spectrum.
  • the course of the recorded frequency spectrum is preferably the course of the
  • the significance of the deviations is assessed before classifying the deviations according to the type of error. Minor deviations in the characteristic course of the frequency spectrum, which may be caused by fluctuations in temperature or in tolerances of the fuel supply system, are therefore not taken into account. Only those deviations that are judged to be significant are taken into account in the diagnosis of the fuel supply system.
  • a fuel supply system in in which an n-cylinder fuel pump with a certain basic frequency is arranged, it is proposed that if the amplitude of the frequency component of n-times the basic frequency of the fuel pump drops, the deviation is classified as being caused by a fault in the fuel pump.
  • an n-cylinder fuel pump in particular an n-cylinder high-pressure delivery pump of a common rail accumulator injection system of a direct-injection internal combustion engine, pressure pulsations with the n-fold basic frequency of an operating cycle occur during operation of the fuel pump.
  • the basic frequency of the fuel pump can therefore be used to carry out a differentiated diagnosis of faults in the fuel supply system in such a way that a distinction is made between faults in the fuel pump and other faults in the fuel supply system.
  • Basic frequency of the fuel pump the deviation is classified as being caused by a fault of the pump cylinder of the fuel pump.
  • the basic frequency of the fuel pump is only ⁇ in a frequency component with ⁇ in ⁇ r relatively low amplitude. If, in addition to a decrease in the amplitude of the frequency component at the n-fold basic frequency of the fuel pump, the frequency component at the basic frequency of the fuel pump increases, this is a sure sign that there is a fault in one of the pump cylinders of the fuel pump.
  • the decrease or increase in the amplitude of the frequency component is determined on the basis of amplitude thresholds, which are undershot or exceeded.
  • the amplitude threshold values are usually dependent on the load and the number of revolutions of the fuel pumps of the fuel supply system, ie. H. the analysis of the frequency spectrum should be carried out depending on both the load and the speed.
  • the mean value of the recorded fuel pressure is subtracted before the analysis of the frequency spectrum.
  • the invention based on the device for diagnosing a fuel supply system of the type mentioned at the beginning, proposes that the device have means for carrying out the
  • FIG. 1 shows a flowchart of a method according to the invention in accordance with a preferred embodiment
  • FIG. 1 shows the course of the recorded Fuel pressure
  • FIG. 3 shows the course of the frequency spectrum of a fuel supply system working incorrectly
  • Figure 4 shows the course of the frequency spectrum ⁇ in ⁇ s
  • Fuel supply system in which a defective fuel pump works.
  • the present invention relates to a method for diagnosing a fuel supply system of an internal combustion engine.
  • the method according to the invention allows the fault to be differentiated individually
  • a fault of a fuel pump of the fuel supply system can be diagnosed with the method according to the invention.
  • the fuel supply system in which the method according to the invention is used, is preferably designed as a common rail memory injection system of a direct injection internal combustion engine.
  • fuel from ⁇ in ⁇ m fuel tank is replaced by an as
  • Electrofuel pump designed pre-feed pumps are first fed to a downstream high-pressure feed pump.
  • the high-pressure feed pump delivers the fuel at a very high pressure into a high-pressure fuel reservoir, from where it reaches a combustion chamber of the internal combustion engine via injectors.
  • the fuel that is not required by the internal combustion engine usually flows back through the high-pressure fuel tank through its return line into the fuel tank. In d ⁇ m
  • High-pressure fuel storage is a high-pressure sensor arranged, which measures the fuel pressure in the high-pressure fuel reservoir and supplies a high-pressure control which regulates the fuel pressure in the high-pressure fuel reservoir to a predetermined value.
  • the method according to the invention is started in a function block 1 in FIG.
  • the recording of the course of the fuel pressure can take place continuously, at regular times or at selected times.
  • the frequency spectrum of the measured fuel pressure curve is formed in a function block 3.
  • the frequency spectrum is formed, for example, by means of a Fourier transformation.
  • the frequency spectrum is then analyzed.
  • the frsqu ⁇ ance component is first multiplied n times
  • Basic frequency of the fuel pump with ⁇ in ⁇ m speed-dependent amplitude threshold value. Furthermore, the frequency component of the basic frequency of the fuel pump is compared with ⁇ in ⁇ m further speed-dependent amplitude threshold values.
  • a diagnosis of a common rail storage injection system is carried out, in which a 3-cylinder high-pressure feed pump works.
  • pressure pulsations occur with a 3-fold basic frequency of a work cycle.
  • the pressure pulsations can be seen in the frequency spectrum of the fuel pressure curve at three times the basic frequency of the high-pressure delivery pumps with a frequency component with a relatively large amplitude.
  • a fault in the high-pressure feed pump leads to a drop the amplitude of this frequency component, which is determined. Furthermore, a fault in one of the pump cylinders of the high-pressure feed pump additionally leads to an increase in the amplitude of the frequency component at the basic frequency of the high-pressure feed pump.
  • the decrease or the increase in the amplitudes of these frequency components can be determined on the basis of amplitude thresholds which are below or exceeded.
  • a query block 5 checks whether the course of the frequency spectrum at the 1-fold or 3-fold basic frequency of the high-pressure feed pump is above or below a predetermined amplitude threshold. If not, the high-pressure feed pump is in order (function block 6) and the method according to the invention returns to function block 1.
  • the dashed line between the function block 6 and the function block 1 is intended to clarify that the method according to the present exemplary embodiment is not called continuously, but cyclically or triggered.
  • the high-pressure delivery pump block is the function (7).
  • An error message is then set in a function block 8.
  • FIG. 2 shows the measured course of the fuel pressure in the high-pressure fuel tank over a period of 0.5 seconds.
  • the fuel pressure was measured at a speed of the internal combustion engine of 2080 rpm.
  • the basic frequency of the working cycle of the 3-cylinder high-pressure feed pump of the common rail fuel injection system is 17.3 Hz.
  • FIG. 3 shows the frequency spectrum of the measured fuel pressure curve from FIG. 2.
  • the frequency component of the 'Hochtik conceptpump ⁇ with 3- fach ⁇ r Grundfrequ ⁇ nz (52 Hz) and d ⁇ r Frequenzant ⁇ il of injections (4-cylinder internal combustion engine, 69 Hz) to be recognized.
  • the 1-fold basic frequency (17.3 Hz) no conspicuous frequency component can be seen.
  • FIG. 4 shows the frequency spectrum of the measured fuel pressure with a defective high-pressure delivery pump. Due to the perfect high-pressure delivery pump, the efficiency of the fuel pump drops, which leads to a decrease in the amplitude of the fresquantant at 3 times the fundamental frequency. The amplitude has dropped from just under 300 (FIG. 3) to approximately 120 (FIG. 4). If only the single pump cylinder of the high-pressure feed pump is defective, the amplitude of the frequency component of three times the fundamental frequency also drops. In addition to the frequency spectrum, there is also a frequency component at 1 times the basic frequency of the high-pressure delivery pump. The amplitude of this
  • Frequency share has increased from about 20 (FIG. 3) to over 100 (FIG. 4).

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

The invention relates to a method and a device for the diagnosis of a fuel supply system pertaining to an internal combustion engine. The aim of the invention is to enable differentiation of an error with regard to the individual components of the fuel supply system. The invention provides a method which is characterised by the following steps: detecting the course of the fuel pressure in the fuel supply system (2), producing the frequency spectrum of the fuel pressure course (3) and analysing the frequency spectrum (4, 5). The analysis of the frequency spectrum preferably comprises the following steps: comparing the course of the detected frequency spectrum to the course of the frequency spectrum of a flawlessly working fuel supply system in this operating point and classifying the deviations according to the kind of error in the fuel supply system by which said errors were produced, when there are deviations between the courses of the frequency spectrums.

Description

Verfahren und Vorrichtung zur Diagnose eines KraftstoffversorgungssystemsMethod and device for diagnosing a fuel supply system
Stand der TechnikState of the art
Die vorliegende Erfindung betrifft ein Verfahren und eineThe present invention relates to a method and a
Vorrichtung zur Diagnose eines Kraftstoffversorgungssystems einer Brennkraftmaschine.Device for diagnosing a fuel supply system of an internal combustion engine.
Ein Kraftstoffversorgungssystem einer Brennkraftmaschine dient dazu, der Brennkraftmaschine Kraftstoff aus einemA fuel supply system of an internal combustion engine is used to deliver fuel from an internal combustion engine
Kraftstoffbehälter zuzuführen. Der Kraftstoff wird dabei von einer Kraftstoffpumpe aus dem Kraftstoffbehälter über eine Druckleitung zu einem an der Brennkraftmaschine befindlichen Kraftstoffverteiler mit Einspritzventilen gepumpt. An dem Kraftstoffvεrteilεr oder an anderer Stelle in dem Kraftstoffversorgungssystem ist üblicherweise ein Drucksεnsor angeordnet . Durch den Drucksensor wird der Kraftstoffdruck in dem Kraftstoffversorgungssystem gemessen und an eine Regelung weitergeleitet. Die Regelung hält den Druck in dem Kraftstoff ersorgungssystem, insbesondere in dem KraftstoffVerteiler , auf einem vorgegebenen Wert. Die von der Brennkraftmaschine nicht benötigte Kraftstoffmenge wird üblicherweise aus dem Kraftstoffvεrteilεr über einε Rücklaufleitung zurück in den Kraf stoffbehälter geführt.Feed fuel tank. The fuel is pumped from a fuel pump from the fuel tank via a pressure line to a fuel distributor on the internal combustion engine with injection valves. A pressure sensor is usually arranged on the fuel distributor or elsewhere in the fuel supply system. The fuel pressure in the fuel supply system is measured by the pressure sensor and forwarded to a control system. The control keeps the pressure in the fuel supply system, in particular in the fuel rail, at a predetermined value. The amount of fuel not required by the internal combustion engine is usually fed from the fuel distributor via a return line back into the fuel tank.
Das Kraftstoffversorgungssystem kann als ein Hochdruck- Kraftstoffversorgungssystem, insbesondere als ein Common- Rail-Speichereinspritzsystem für eine direktεinspritzende Brennkraftmaschine, ausgebildet sein, bei dem ein Kraftstoffhochdruckspeicher als Kraftstoffvertεiler vorgesehen ist. Bei Common-Rail-Speichereinspritzsyste en wird Kraftstoff aus dem Kraftstoffbehälter durch eine alsThe fuel supply system can be used as a high-pressure fuel supply system, in particular as a common Rail memory injection system for a direct-injection internal combustion engine, in which a high-pressure fuel reservoir is provided as a fuel distributor. In common rail memory injection systems, fuel is drawn from the fuel tank by an as
Elektrokraftstoffpumpe ausgebildete Vorförderpumpε zunächst einεr nachgεordneten Hochdruckfördεrpumpε zugeführt. Die Hochdruckförderpumpe fördert den Kraftstoff dann mit einem sehr hohen Druck in den Kraftstoffhochdruckspεichεr, von wo aus εr über diε als Injεktoren ausgεbildεtenElectric fuel pump designed pre-feed pumps are first fed to a downstream high-pressure feed pump. The high-pressure feed pump then delivers the fuel at a very high pressure into the high-pressure fuel tank, from where it is designed as injectors
Einspritzventile in einen Brennraum der Brεnnkraftmaschine gelangt. In dem Kraftstoffhochdruckspeicher sind Drucksensoren angeordnet, um den Kraftstoffdruck in dem Kraf stoffhochdruckspeicher für die Regelung des Kraftstoffdrucks zu messen. Ein solchesInjection valves get into a combustion chamber of the internal combustion engine. Pressure sensors are arranged in the high-pressure fuel reservoir in order to measure the fuel pressure in the high-pressure fuel reservoir for regulating the fuel pressure. Such one
Kraftstoffversorgungssystem ist bspw. aus der DE 195 39 885 AI bekannt.Fuel supply system is known, for example, from DE 195 39 885 AI.
Aus dem Stand der Technik ist es bekannt, aus einer Regelabwεichung dεr Regelung des Kraftstoffdrucks in demIt is known from the prior art, from a control deviation of the control of the fuel pressure in the
Kraftstoffversorgungssystem ganz allgemεin einen Fehler des Kraftstoffversorgungssystems abzuleiten. Eine differenzierte Diagnose des Fehlεrs auf εinzelne Komponenten des Kraftstoffversorgungssystems ist nicht möglich. Es wäre jedoch wünschenswert, insbesondεre einenTo derive fuel supply system in general a fault of the fuel supply system. A differentiated diagnosis of the fault on individual components of the fuel supply system is not possible. However, it would be desirable, especially one
Defekt der Kraftstoffpumpe des Kraftstoffversorgungssystems diagnostizieren zu können. Eine defekte Kraftstoffpumpe kann dazu führen, dass der gεforderte Kraftstoffdruck in dem Kraftstoffversorgungssystem nicht mehr erreicht werden kann uns es damit in bestimmtεn Betriebspunkten derDefect the fuel pump of the fuel supply system to be able to diagnose. A defective fuel pump can lead to the fact that the required fuel pressure in the fuel supply system can no longer be reached, and so it can be found in certain operating points
Brennkraftmaschine zu abgasrelevanten und leistungsrelevanten Fehlern in der Gemischbildung kommt .Internal combustion engine comes to exhaust-related and performance-related errors in the mixture formation.
Deshalb ist es die Aufgabe der vorliegenden Erfindung, eine diffεrenzierte Diagnosε εinεs Fehlers desIt is therefore the object of the present invention to provide a differentiated diagnosis of the
Kraftstoffversorgungssystems zu ermöglichen. Zur Lösung dieser Aufgabe schlägt die Erfindung ausgehend von dem Verfahren zur Diagnose einesAllow fuel supply system. To achieve this object, the invention proposes starting from the method for diagnosing a
Kraftstoffversorgungssystems der eingangs genannten Art ein Verfahren vor, das gekennzεichnεt ist durch diε nachfolgendεn Schrittε:Fuel supply system of the type mentioned in the introduction, a method which is characterized by the following step:
Aufnahme des Verlaufs des Kraftstoffdrucks in dem Kraftstoffversorgungssytem;Recording the course of the fuel pressure in the fuel supply system;
- Bilden des Frequenzsprεktrums des Kraftstoffdruckverlaufs; und- Forming the frequency spectrum of the fuel pressure curve; and
Analyse des Frequenzsprektrums .Analysis of the frequency spectrum.
Der Verlauf des Kraftstoffdrucks in dεmThe course of the fuel pressure in dεm
Kraftstoffversorgungssystem kann bspw. an Hand εinεs physikalischen Modells des Kraftstoffversorgungssystems bestimmt werden. Dazu werden dem physikalischen Modell Zustandsgrößen des Kraftstoffversorgungssystems und/oder der Brennkraftmaschine zugeführt, aus denen der Verlauf desThe fuel supply system can be determined, for example, using εinεs physical model of the fuel supply system. For this purpose, state variables of the fuel supply system and / or the internal combustion engine are supplied to the physical model, from which the course of the
Kraftstoffdrucks modelliεrt wird.Fuel pressure is modeled.
Vorteilhafterweise wird der Kraftstoffdruck in dεm Kraftstoffvεrsorgungssytεm jedoch mittels eines Drucksensors gemessen. Ein solcher Drucksensor ist üblicherweise in dem Kraftstoffversorgungssystem zum Erfassen des Kraftstoffdrucks für eine Regelung dεs Kraftstoffdrucks in dεm Kraftstoffversorgungssystεm bereits vorhanden und kann auch zur Aufnahme des Kraftstoffdruckverlaufs gemäß dεr vorliεgεndεn Erfindung hεrangezogen werden.The fuel pressure in the fuel supply system is, however, advantageously measured by means of a pressure sensor. Such a pressure sensor is usually already present in the fuel supply system for detecting the fuel pressure for regulating the fuel pressure in the fuel supply system and can also be used to record the fuel pressure curve in accordance with the present invention.
Zur Diagnosε wird das Frequenzspεktrum desThe frequency spectrum of the
Kraftstoffdruckvεrlaufs gebildet. Das Frequenzspεktrum wird vortεilhaftεrweisε mittεls einer Fouriertransformation dεs Kraftstoffdruckverlaufs gebildet. Durch die Arbeitsweise dεr Kraftstoffpu pε in dem Kraftstoffversorgungssystem kommt es zu einem charakteristischen Frεquenzspektrum des Kraftstoffdruckvεrlaufs . Für eine differenziεrtε Diagnosε εines Fehlers des Kraftstoffversorgungssystems wird das Frequenzspektrum analysiert.Fuel pressure run formed. The frequency spectrum is advantageously formed by means of a Fourier transformation of the fuel pressure curve. By the way it works The fuel pump in the fuel supply system results in a characteristic frequency spectrum of the fuel pressure curve. The frequency spectrum is analyzed for a differentiated diagnosis of a fault in the fuel supply system.
Im Einzelnen hat das Frequenzspektrum desIn detail, the frequency spectrum of the
Kraftstoffdruckvεrlaufs in einem fehlerfrεiεnFuel pressure curve in a fault-free state
Kraftstoffversorgungssystem einen für das jeweiligε Kraftstoff ersorgungssystem charakteristischεn Vεrlauf .Fuel supply system a course characteristic of the respective fuel supply system.
Bestimmte Fehler des KraftstoffvεrsorgungssystεmΞ verändern den charakteristischen Verlauf des Frequenzspektrums in einer bestimmten Weisε. Im Rahmεn der Analyse des Frεquεnzspektrums wird versucht, diese Vεrändεrungεn des charakteristischen Verlaufs zu εrkennen und aus dεnCertain errors in the fuel supply system change the characteristic course of the frequency spectrum in a certain way. As part of the analysis of the frequency spectrum, an attempt is made to recognize these changes in the characteristic profile and from them
Veränderungεn auf dεn verursachenden Fehler zu schließen. Zum Erkennεn dεr Vεrändεrungεn dεs charaktεristischεn Vεrlaufs wird das Frequenzspektrum bspw. mit Schwellenwerten verglichεn. Ein Anstiεg bzw. ein Abfallen der Amplitude des Frequenzspektrums kann durch εinεnTo conclude changes to the errors causing them. In order to identify the changes in the characteristic course, the frequency spectrum is compared, for example, with threshold values. An increase or decrease in the amplitude of the frequency spectrum can be caused by εinεn
Vεrglεich mit εntsprεchεnden Amplitudenschwellenwεrtεn erkannt werden. Ebenso kann ein Vεrschiεbεn von charaktεristischεn Frεquεnzantεilen hin zu höheren bzw. niedrigerεn Frεquenzen durch εinen Verglεich mit entsprechenden Frequenzschwεllεnwεrten erkannt werden. Diε Verknüpfung einer bestimmten Veränderung des charakteristischen Verlaufs des Frequenzspektrums mit dem verursachenden Fehler kann bspw. mittels εines Expertεnsystems εrfolgen. Mit dεm erfindungsgεmäßεn Vεrfahrεn ist somit εine differenzierte Diagnose eines Fehlers des Kraftstoff ersorgungssystems möglich.Compared with corresponding amplitude threshold values. Likewise, a shift from characteristic fresquantant lines to higher or lower fresquences can be recognized by comparing them with corresponding frequency threshold values. The linking of a specific change in the characteristic course of the frequency spectrum with the causing error can be achieved, for example, by means of an expert system. A differentiated diagnosis of a fault in the fuel supply system is thus possible with the method according to the invention.
Gemäß εinεr vortεilhaften Weiterbildung dεr vorliegεnden Erfindung umfasst die Analyse des Frequenzspektrums die nachfolgenden Schritte: Vεrglεich des Verlaufs des aufgenommenεn Frequenzspektrums mit dem Verlauf des Frequenzspektrums eines fehlerfrei arbeitenden Kraftstoff ersorgungssystems ,■ undAccording to an advantageous further development of the present invention, the analysis of the frequency spectrum comprises the following steps: Comparing the course of the recorded frequency spectrum with the course of the frequency spectrum of a fuel supply system operating without errors, ■ and
falls Abweichungεn zwischen den Verläufεn dεr Frequenzspektren vorliegen, Klassifizierεn der Abweichungen nach der Art der Fehler in dem Kraf stoffversorgungssystem, durch die sie hervorgeruf n wεrden.if there are deviations between the curves of the frequency spectra, classify the deviations according to the type of errors in the fuel supply system which would cause them.
Bestimmte Fehler des Kraftstoffversorgungssystems verändern den charakteristischen Verlauf des Frequenzspektrums des Kraftstoffdruckverlaufs in einer definierten Weise. So kann insbesondere ein Fehler der Kraftstoffpumpe desCertain errors in the fuel supply system change the characteristic course of the frequency spectrum of the fuel pressure course in a defined manner. In particular, a fault in the fuel pump of the
Kraftstoffversorgungssystems und bei mehrzylindrigen Kraftstoffpumpen ein Fehler in einεm dεr Pumpenzylinder aus dem Verlauf des aufgenommenen Frequεnzspεktrums diagnostiziert werden. Dεr Verlauf des aufgenommenen Frequenzspektrums wird vorzugsweisε mit dem Verlauf desFuel supply system and in multi-cylinder fuel pumps, a fault in one of the pump cylinders can be diagnosed from the course of the recorded frequency spectrum. The course of the recorded frequency spectrum is preferably the course of the
Frequenzspektrums εinεs in diεsem Betriebspunkt fehlεrfrεi arbeitenden Kraftstoffvεrsorgungssystεms verglichen.Frequency spectrum εinεs in this operating point of incorrectly working fuel supply systems compared.
Gemäß einer bevorzugten Ausführungsform dεr vorliegenden Erfindung wird vor dεm Klassifiziεrεn der Abweichungεn nach der Art der Fehler diε Erheblichkeit der Abweichungen beurtεilt . Geringe Abweichungen des charakteristischen Verlaufs des Frεquεnzspεktrums , diε ihre Ursache in Temperatu schwankungεn oder in Toleranzen des Kraftstoff ersorgungssystems haben können, bleiben somit unberücksichtigt. Nur solche Abweichungen, die als erheblich beurtεilt werden, werden bei der Diagnose des Kraftstoffversorgungssystems berücksichtigt .According to a preferred embodiment of the present invention, the significance of the deviations is assessed before classifying the deviations according to the type of error. Minor deviations in the characteristic course of the frequency spectrum, which may be caused by fluctuations in temperature or in tolerances of the fuel supply system, are therefore not taken into account. Only those deviations that are judged to be significant are taken into account in the diagnosis of the fuel supply system.
Gemäß einεr vorteilhaften Weitεrbildung der vorliegenden Erfindung wird bei einem Kraftstoffversorgungssystem, in dem eine n-Zylinder-Kraftstoffpumpe mit einer bestimmten Grundfrequεnz angεordnεt ist, vorgeschlagen, dass bei einem Absinken der Amplitude des Frequεnzanteils der n-fachen Grundfrequεnz der Kraftstoffpumpe die Abweichung als von einem Fehler der Kraftstoffpumpe hervorgerufen klassifiziert wird. Bei εinεr n-Zylindεr-Kraftstoffpumpε, insbεsondere bei einer n-Zylindεr-Hochdruckfördεrpumpe εines Common-Rail-Speichεrεinspritzsystems einεr direkteinspritzenden Brennkraftmaschine, entstehen beim Betrieb der Kraftstoffpumpe Druckpulsationen mit der n- fachεn Grundfrεquenz eines Arbeitsspiels. Durch die Aufnahme des Verlaufs dεs Kraftstoffdrucks und das Bilden des Frequεnzspεktrums des Kraftstoffdruckverlaufs ist in dem Vεrlauf des Frequenzspektrums deutlich ein Frequenzanteil bei der n-fachen Grundfrequenz derAccording to an advantageous development of the present invention, in a fuel supply system, in in which an n-cylinder fuel pump with a certain basic frequency is arranged, it is proposed that if the amplitude of the frequency component of n-times the basic frequency of the fuel pump drops, the deviation is classified as being caused by a fault in the fuel pump. In the case of an n-cylinder fuel pump, in particular an n-cylinder high-pressure delivery pump of a common rail accumulator injection system of a direct-injection internal combustion engine, pressure pulsations with the n-fold basic frequency of an operating cycle occur during operation of the fuel pump. By recording the course of the fuel pressure and forming the frequency spectrum of the fuel pressure course, there is clearly a frequency component at n times the fundamental frequency in the course of the frequency spectrum
Kraftstoffpumpe zu erkennen. Falls die Amplitude des Frεquenzanteils der n-fachen Grundfrequεnz der Kraf stoffpumpe absinkt, ist dies εin sicherεs Zeichen für das Vorliegεn eine Fehlers dεr Kraftstoffpumpε . Durch eine Auswertung des Frequenzspεktrums bεi der n-fachenDetect fuel pump. If the amplitude of the frequency component of the n-fold fundamental frequency of the fuel pump drops, this is a sure sign of the presence of a fault in the fuel pump. By evaluating the frequency spectrum to n times
Grundfrequenz der Kraftstoffpumpe kann somit eine differenzierte Diagnose von Fehlεrn des Kraftstoffvεrsorgungssystεms dahingehend durchgeführt werden, dass zwischen Fehlern dεr Kraftstoffpumpe und sonstigen Fehlern des Kraftstoffversorgungssystεms untεrschieden wird.The basic frequency of the fuel pump can therefore be used to carry out a differentiated diagnosis of faults in the fuel supply system in such a way that a distinction is made between faults in the fuel pump and other faults in the fuel supply system.
Gεmäß εinεr weiteren bevorzugten Ausführungsform der vorliegenden Erfindung wird vorgeschlagen, dass bei einεr Zunahmε dεr Amplitude des Frequεnzantεils der 1-fachenAccording to a further preferred embodiment of the present invention, it is proposed that with an increase in the amplitude of the frequency element of 1 times
Grundfrεquenz dεr Kraftstoffpumpe die Abweichung als von einem Fεhlεr εines der Pumpenzylinder der Kraftstoffpumpe hervorgerufen klassifiziert wird. In dεm charakteristischen Verlauf des Frequenzspεktrums eines fehlerfrεi arbεitenden Kraf stoffversorgungssystems ist bεi dεr Grundfrεquεnz dεr Kraftstoffpumpε lεdiglich εin Frequenzantεil mit εinεr relativ geringen Amplitude zu erkennen. Falls zusätzlich zu einem Absinken der Amplitude des Frequenzanteils bei der n- fachen Grundfrequenz der Kraftstoffpumpe der Frequenzanteil bei der Grundfrequenz der Kraftstoffpumpe ansteigt, ist dies ein sicheres Zeichen dafür, dass ein Fehler eines der Pumpenzylinder der Kraftstoffpumpe vorliegt.Basic frequency of the fuel pump the deviation is classified as being caused by a fault of the pump cylinder of the fuel pump. In the characteristic course of the frequency spectrum of a fault-free fuel supply system, the basic frequency of the fuel pump is only εin a frequency component with εinεr relatively low amplitude. If, in addition to a decrease in the amplitude of the frequency component at the n-fold basic frequency of the fuel pump, the frequency component at the basic frequency of the fuel pump increases, this is a sure sign that there is a fault in one of the pump cylinders of the fuel pump.
Vorteilhaftεrwεise wird das Absinken oder diε Zunahme der Amplitude des Frequεnzanteils an Hand von Amplitudenschwellen εrmittεlt, diε untεrschrittεn bzw. überschritten werdεn. Die Amplitudenschwεllεnwεrtε sind üblichεrwεise abhängig von der Last und dεr Drεhzahl der Kraftstoffpumpε des Kraftstoff ersorgungssystems, d. h. die Analyse des Frequεnzspεktrums sollte sowohl last- als auch drehzahlabhängig durchgeführt werdεn. Um εinεn Glεichanteil in dεm aufgenommenen Frequenzspektrum zu vermeiden, wird gemäß einer anderen bevorzugten Ausführungsfor der vorliegenden Erfindung vorgeschlagεn, dass vor dεr Analyse des Frequenzsprektrums der Mittelwεrt des aufgenommenen Kraftstoffdrucks subtrahiert wird.Advantageously, the decrease or increase in the amplitude of the frequency component is determined on the basis of amplitude thresholds, which are undershot or exceeded. The amplitude threshold values are usually dependent on the load and the number of revolutions of the fuel pumps of the fuel supply system, ie. H. the analysis of the frequency spectrum should be carried out depending on both the load and the speed. In order to avoid an equal proportion in the recorded frequency spectrum, it is proposed according to another preferred embodiment of the present invention that the mean value of the recorded fuel pressure is subtracted before the analysis of the frequency spectrum.
Als weitere Lösung der vorliegenden Aufgabe schlägt die Erfindung ausgehend von dεr Vorrichtung zur Diagnosε eines Kraftstoffversorgungssystems der eingangs genanntεn Art vor, dass die Vorrichtung Mittel zur Durchführung desAs a further solution to the present problem, the invention, based on the device for diagnosing a fuel supply system of the type mentioned at the beginning, proposes that the device have means for carrying out the
Verfahrens nach einem der Ansprüche 1 bis 9 aufweist.Method according to one of claims 1 to 9.
Ein bevorzugtes Ausführungsbeispiel der vorliegenden Erfindung wird im Folgendεn an Hand dεr Zeichnungen näher erläutert. Es zeigen:A preferred embodiment of the present invention is explained in more detail below with reference to the drawings. Show it:
Figur 1 ein Ablaufdiagram einεs erfindungsgemäßen Verfahrens gemäß einεr bevorzugten Ausführungsform;1 shows a flowchart of a method according to the invention in accordance with a preferred embodiment;
Figur 2 den Verlauf des aufgenommεnεn Kraftstoffdrucks ;Figure 2 shows the course of the recorded Fuel pressure;
Figur 3 den Verlauf des FrequεnzSpektrums eines fehlεrfrεi arbeitenden Kraftstoffversorgungssystems ; undFIG. 3 shows the course of the frequency spectrum of a fuel supply system working incorrectly; and
Figur 4 den Vεrlauf dεs Frεquenzspεktrums εinεsFigure 4 shows the course of the frequency spectrum εinεs
KraftstoffVersorgungssystems, in dem εine def kte Kraftstoffpumpe arbεitεt .Fuel supply system, in which a defective fuel pump works.
Diε vorliegende Erfindung betrifft εin Verfahren zur Diagnose eines Kraf stoffvεrsorgungssyΞtεms einer Brennkraftmaschine . Bei Fehlεrn dεs Kraftstoffversorgungssystems erlaubt das εrfindungsgεmäßε Verfahren eine Differεnziεrung des Fehlεrs auf εinzelneThe present invention relates to a method for diagnosing a fuel supply system of an internal combustion engine. In the event of faults in the fuel supply system, the method according to the invention allows the fault to be differentiated individually
Komponentεn dεs Kraftstoffvεrsorgungssystεms . Insbεsondεre kann mit dem εrfindungsgεmäßεn Vεrfahrεn εin Fehler einer Kraftstoffpumpe des Kraftstoffvεrsorgungssystεms diagnostiziert wεrden.Components of the fuel supply system. In particular, a fault of a fuel pump of the fuel supply system can be diagnosed with the method according to the invention.
Das Kraftstoffvεrsorgungssystεm, bei dεm das erfindungsgemäße Verfahren eingesetzt wird, ist vorzugsweisε als ein Common-Rail-Speichereinspritzsystem einer direktεinspritzεnden Brennkraftmaschine ausgebildet. Bei Common-Rail-Spεichereinspritzsystεmεn wird Kraftstoff aus εinεm Kraftstoffbehälter durch eine alsThe fuel supply system, in which the method according to the invention is used, is preferably designed as a common rail memory injection system of a direct injection internal combustion engine. In common-rail fuel injection systems, fuel from εinεm fuel tank is replaced by an as
Elektrokraftstoffpumpe ausgebildete Vorförderpumpε zunächst einer nachgεordnetεn Hochdruckförderpumpε zugeführt. Diε Hochdruckförderpumpε fördert den Kraftstoff mit einem sehr hohen Druck in einen Kraftstoffhochdruckspeicher , von wo aus εr über Injektorεn in einen Brennraum der Brennkraftmaschine gelangt . Die von dεr Brennkraftmaschine nicht benötigte Kraf stoffmεngε strömt üblicherweisε durch dεn Kraftstoffhochdruckspεichεr über εinε Rücklaufleitung zurück in den Kraftstoffbehältεr . In dεmElectrofuel pump designed pre-feed pumps are first fed to a downstream high-pressure feed pump. The high-pressure feed pump delivers the fuel at a very high pressure into a high-pressure fuel reservoir, from where it reaches a combustion chamber of the internal combustion engine via injectors. The fuel that is not required by the internal combustion engine usually flows back through the high-pressure fuel tank through its return line into the fuel tank. In dεm
Kraftstoffhochdruckspeicher ist ein Hochdrucksensor angeordnet, der den Kraftstoffdruck in dem Kraftstoffhochdruckspeichεr misst und εiner Hochdruckregelung zuführt, die den Kraftstoffdruck in dem Kraftstoffhochdruckspeicher auf einen vorgegebenen Wert regelt.High-pressure fuel storage is a high-pressure sensor arranged, which measures the fuel pressure in the high-pressure fuel reservoir and supplies a high-pressure control which regulates the fuel pressure in the high-pressure fuel reservoir to a predetermined value.
In einem Funktionsblock 1 in Figur 1 wird das erfindungsgemäße Verfahren gestartet. Zunächst wird in einem Funktionsblock 2 mittels des Hochdrucksensors der in dεm Kraftstoffhochdruckspeicher herrschεndε Kraftstoffdruck gεmessen. Die Aufnahme des Verlaufs des Kraftstoffdrucks kann kontinuiεrlich, zu regelmäßigen Zeitpunkten oder zu ausgεwählten Zeitpunkten erfolgen.The method according to the invention is started in a function block 1 in FIG. First, the fuel pressure prevailing in the high-pressure fuel reservoir is measured in a functional block 2 by means of the high-pressure sensor. The recording of the course of the fuel pressure can take place continuously, at regular times or at selected times.
In einem Funktionsblock 3 wird das Frequεnzspεktrum des gεmεssenen Kraftstoffdruckverlaufs gebildet. Das Frequenzspεktrum wird bspw. mittels einer Fouriertransformation gebildet. Anschließend wird das Frequenzspεktrum analysiert. Dazu wird in einem Funktionsblock 4 zunächst dεr Frεquεnzanteil der n-fachenThe frequency spectrum of the measured fuel pressure curve is formed in a function block 3. The frequency spectrum is formed, for example, by means of a Fourier transformation. The frequency spectrum is then analyzed. For this purpose, in a function block 4, the frsquεance component is first multiplied n times
Grundfrequenz der Kraf stoffpumpe mit εinεm drehzahlabhängigen Amplitudenschwellenwert vεrglichεn. Des Weitεrεn wird dεr Frεquenzanteil dεr Grundfrequεnz der Kraftstoffpumpε mit εinεm wεiteren drehzahlabhängigen Amplitudenschwellenwεrt vεrglichεn.Basic frequency of the fuel pump with εinεm speed-dependent amplitude threshold value. Furthermore, the frequency component of the basic frequency of the fuel pump is compared with εinεm further speed-dependent amplitude threshold values.
Im Einzelnen wird in dem vorliegendεn Ausführungsbeispiel eine Diagnose eines Common-Rail-Speichεrεinspritzsystεms durchgεführ , in dεm eine 3 -Zylinder-Hochdruckförderpumpe arbeitet. Beim Einsatz der 3 -Zylinder-Hochdruckförderpumpe entstehεn Druckpulsationen mit dεr 3 -fachen Grundfrequenz eines Arbeitsspiels. Diε Druckpulsationεn sind in dem Frequenzspεktrum dεs Kraftstoffdruckverlaufs bei der 3- fachen Grundfrequεnz der Hochdruckförderpumpε mit einem Frequenzantεil mit relativ großer Amplitude zu erkennen.In detail, in the present exemplary embodiment, a diagnosis of a common rail storage injection system is carried out, in which a 3-cylinder high-pressure feed pump works. When using the 3-cylinder high-pressure feed pump, pressure pulsations occur with a 3-fold basic frequency of a work cycle. The pressure pulsations can be seen in the frequency spectrum of the fuel pressure curve at three times the basic frequency of the high-pressure delivery pumps with a frequency component with a relatively large amplitude.
Ein Fehler der Hochdruckförderpumpε führt zu einεm Absinken der Amplitude dieses Frequenzantεils, dεr εrmittelt wird. Des Weiteren führt ein Fehler eines der Pumpεnzylinder der Hochdruckförderpumpe zusätzlich zu einem Anstieg der Amplitude des Frequenzanteils bεi dεr Grundfrεquεnz der Hochdruckfördεrpumpe .A fault in the high-pressure feed pump leads to a drop the amplitude of this frequency component, which is determined. Furthermore, a fault in one of the pump cylinders of the high-pressure feed pump additionally leads to an increase in the amplitude of the frequency component at the basic frequency of the high-pressure feed pump.
Das Absinkεn oder die Zunahme der Amplitudεn dieser Frequεnzanteile kann an Hand von Anπplitudenschwellen ermittelt werden, die unterschrittεn bzw. übεrschritten werden. Dazu wird in einem Abfrageblock 5 überprüft, ob dεr Vεrlauf dεs Frequenzspektrums bei der 1-fachen bzw. der 3- fachen Grundfrεquenz dεr Hochdruckförderpumpe obεrhalb bzw. untεrhalb εiner vorgegebenen Amplitudenschwεlle ist. Falls nεin, ist diε Hochdruckförderpumpe in Ordnung (Funktionsblock 6) und das εrfindungsgεmäßε Vεrfahrεn kεhrt zu dεm Funktionsblock 1 zurück. Die gestrichelte Linie zwischen dεm Funktionsblock 6 und dem Funktionsblock 1 soll verdeutlichen, dass das Verfahren gemäß dem vorliegεnden Ausführungsbεispiel nicht kontinuierlich, sondern zyklisch oder getriggert aufgεrufεn wird.The decrease or the increase in the amplitudes of these frequency components can be determined on the basis of amplitude thresholds which are below or exceeded. For this purpose, a query block 5 checks whether the course of the frequency spectrum at the 1-fold or 3-fold basic frequency of the high-pressure feed pump is above or below a predetermined amplitude threshold. If not, the high-pressure feed pump is in order (function block 6) and the method according to the invention returns to function block 1. The dashed line between the function block 6 and the function block 1 is intended to clarify that the method according to the present exemplary embodiment is not called continuously, but cyclically or triggered.
Falls das Frequenzspektrum aufgenommenenIf the frequency spectrum is recorded
Kraftstoffdruckvεrlaufs Abwεichungεn aufweist, die bεi dεr 1-fachεn bzw. bεi dεr 3 -fachen Grundfrequεnz der Hochdruckförderpumpε diε vorgεgεbenεn Amplitudenschwεllεn übεrschrεitεn bzw. untεrschrεitεn, ist die Hochdruckförderpumpε dεfεkt (Funktionsblock 7) . In εinem Funktionsblock 8 wird dann ein Fehlεrspεichεr gεsεtzt .If the pressure of the fuel pressure differs from the 1-fold or 3-fold basic frequency of the high-pressure delivery pump to the predetermined amplitude thresholds, the high-pressure delivery pump block is the function (7). An error message is then set in a function block 8.
In Figur 2 ist dεr gemessene Vεrlauf dεs Kraftstoffdrucks in dεm Kraftstoffhochdruckspεichεr übεr εinεn Zeitraum von 0,5 Sekunden dargestεllt. Dεr Kraftstoffdruck wurdε bei εinεr Drehzahl der Brennkraftmaschine von 2080 U/min gemεssεn. Die Grundfrεquεnz dεs Arbeitsspiels dεr 3- Zylindεr-Hochdruckförderpumpε dεs Common-Rail- Spεicherεinspritzsystems bεträgt 17,3 Hz. In Figur 3 ist das Frεquenzspektrum des gemessenεn Kraftstoffdruckvεrlaufs aus Figur 2 dargestellt. Deutlich ist der Frequenzanteil der' Hochdruckförderpumpε mit 3- fachεr Grundfrequεnz (52 Hz) und dεr Frequenzantεil der Einspritzungen (4-Zylinder-Brennkraftmaschine, 69 Hz) zu erkennen. Bei der 1-fachen Grundfrequenz (17,3 Hz) ist kein auffälliger Frequenzanteil zu erkennen.FIG. 2 shows the measured course of the fuel pressure in the high-pressure fuel tank over a period of 0.5 seconds. The fuel pressure was measured at a speed of the internal combustion engine of 2080 rpm. The basic frequency of the working cycle of the 3-cylinder high-pressure feed pump of the common rail fuel injection system is 17.3 Hz. FIG. 3 shows the frequency spectrum of the measured fuel pressure curve from FIG. 2. Significantly, the frequency component of the 'Hochdruckförderpumpε with 3- fachεr Grundfrequεnz (52 Hz) and dεr Frequenzantεil of injections (4-cylinder internal combustion engine, 69 Hz) to be recognized. At the 1-fold basic frequency (17.3 Hz), no conspicuous frequency component can be seen.
In Figur 4 ist das Frequεnzspektrum des gemessεnen Kraftstoffdrucks bei einεr dεfektεn Hochdruckfördεrpumpε dargestellt. Durch diε dεfekte Hochdruckförderpumpε sinkt dεr Wirkungsgrad dεr Kraftstoffpumpe, was zu εinεm Absinken der Amplitude des Frεquεnzantεils bεi der 3 -fachen Grundfrequenz führt. Die Amplitude ist von knapp 300 (Figur 3) auf εtwa 120 (Figur 4) abgεsunkεn. Ist nur εin εinzelnεr Pumpenzylinder der Hochdruckförderpumpε dεfekt, sinkt die Amplitude des Frequenzanteils der 3- fachen Grundfrequenz ebenfalls. Zusätzlich kommt zu dem Frequεnzspεktrum ein Frequenzantεil bεi dεr 1-fachen Grundfrεquεnz dεr Hochdruckfördεrpumpε hinzu. Die Amplitude diesεsFIG. 4 shows the frequency spectrum of the measured fuel pressure with a defective high-pressure delivery pump. Due to the perfect high-pressure delivery pump, the efficiency of the fuel pump drops, which leads to a decrease in the amplitude of the fresquantant at 3 times the fundamental frequency. The amplitude has dropped from just under 300 (FIG. 3) to approximately 120 (FIG. 4). If only the single pump cylinder of the high-pressure feed pump is defective, the amplitude of the frequency component of three times the fundamental frequency also drops. In addition to the frequency spectrum, there is also a frequency component at 1 times the basic frequency of the high-pressure delivery pump. The amplitude of this
Frequenzantεils ist von εtwa 20 (Figur 3) auf übεr 100 (Figur 4) angestiegεn. Frequency share has increased from about 20 (FIG. 3) to over 100 (FIG. 4).

Claims

Ansprüche Expectations
1. Verfahren zur Diagnose eines1. Procedure for diagnosing a
Kraftstoffversorgungssystems einer Brennkraftmaschine, gekennzeichnet durch die nachfolgenden Schritte :Fuel supply system of an internal combustion engine, characterized by the following steps:
Aufnahme dεs Vεrlaufs dεs Kraftstoffdrucks in dεm Kraftstoffvεrsorgungssytεm (2) ; - Bildεn des Frequεnzsprεktrums des Kraftstoffdruckverlaufs (3); und Analyse des Frequenzsprektrums (4, 5) .Recording the flow of the fuel pressure in the fuel supply system (2); - Images of the frequency spectrum of the fuel pressure curve (3); and analysis of the frequency spectrum (4, 5).
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass die Analyse des Frequεnzspεktrums diε nachfolgenden2. The method according to claim 1, characterized in that the analysis of the Frequεnzspεektrums diε subsequent
Schritte umfasst:Steps include:
Vergleich dεs Vεrlaufs dεs aufgenommεnεn Frεquεnzsprektrums mit dεm Vεrlauf des Frequεnzspεktrums eines fehlεrfrεi arbeitenden Kraftstoffversorgungssystεms ; und falls Abweichungen zwischen den Verläufen dεr Frequenzspεktrεn vorliεgεn, Klassi izieren der Abweichungen nach dεr Art dεr Fehlεr in dεm Kraftstoffvεrsorgungssystεm, durch die sie hervorgεrufεn werden.Comparison of the course of the recorded frequency spectrum with the course of the frequency spectrum of a fuel supply system operating incorrectly; and if there are deviations between the courses of the frequency spectra, classify the deviations according to the type of the fault in the fuel supply system by which they are caused.
3. Verfahrεn nach Anspruch 1 odεr 2, dadurch gεkεnnzεichnεt , dass dεr Kraftstoffdruck in dεm3. Verfahrεn according to claim 1 or 2, characterized gεkεnnzεichnεt that dεr fuel pressure in dεm
Kraftstoffvεrsorgungssytεm mittεls εines Drucksεnsors gemessen wird. Fuel supply system is measured by means of a pressure sensor.
4. Verfahrεn nach Anspruch 2 oder 3 , dadurch gekennzeichnεt , dass vor dεm Klassifizieren der Abweichungen nach der Art dεr Fehler die Erheblichkeit der Abweichungen beurteilt wird.4. Verfahrεn according to claim 2 or 3, characterized gekennzeichnεt that before the classification of the deviations according to the type of error the significance of the deviations is assessed.
5. Verfahrεn nach einem der Ansprüche 1 bis 4 , dadurch gekennzeichnεt, dass das Frequenzsprektrum dεs5. Verfahrεn according to one of claims 1 to 4, characterized gekennzeichnεt that the frequency spectrum dεs
Kraftstoffdruckvεrlaufs mittels einεr Fouriεrtransformation dεs Kraftstoffdruckvεrlaufs gebildet wird.Fuel pressure curve is formed by means of a Fourier transformation of the fuel pressure curve.
6. Verfahrεn nach einem dεr Ansprüche 2 bis 5, wobei in dem Kraf stoffversorgungssystem εinε n-Zylindεr- Kraftstoffpumpε mit einer bestimmten Grundfrequenz angeordnet ist, dadurch gekennzeichnεt, dass bei εinεm Absinken dεr Amplitude des Frεquεnzantεils dεr n-fachen Grundfrεquεnz der Kraftstoffpumpe diε Abweichung als von einem Fehlεr dεr Kraftstoffpumpε hervorgεrufen klassifiziert wird (4) .6. The method according to one of claims 2 to 5, wherein εinε n-cylinder fuel pumps with a certain basic frequency are arranged in the fuel supply system, characterized in that when the amplitude of the frequency of the fuel pump decreases, the n-fold basic frequency of the fuel pump is the deviation is classified by an error in the fuel pump (4).
7. Verfahrεn nach Anspruch 6, dadurch gεkεnnzεichnεt, dass bεi εiner Zunahme dεr Amplitudε des Frequenzantεils dεr 1-fachen Grundfrequenz dεr Kraftstoffpumpε diε Abwεichung als von εinem Fehlεr εines der Pumpenzylinder der Kraftstoffpumpe hervorgerufen klassifiziert wird (4) .7. The method according to claim 6, characterized in that, with an increase in the amplitude of the frequency component of the 1-fold basic frequency of the fuel pump, this deviation is classified as being caused by one of the pump cylinder of the fuel pump (4).
8. Verfahren nach Anspruch 6 oder 7, dadurch gekennzεichnet , dass das Absinken oder die Zunahme dεr Amplitude des Frequεnzantεils anhand von Amplitudεnschwellεn εrmittεlt wird, diε unterschritten bzw. überschrittεn wεrdεn (5).8. The method according to claim 6 or 7, characterized in that the decrease or increase in the amplitude of the frequency element is determined on the basis of amplitude thresholds that fall below or exceed (5).
9. Verfahren nach einem der Ansprüche 1 bis 8, dadurch gεkεnnzεichnεt , dass vor dεr Analyse des Frεquen∑sprekurums dεr Mittεlwεrt dεs aufgεnommεnεn Kraftstoffdrucks subtrahiεrt wird. 9. The method according to any one of claims 1 to 8, characterized gεknznichnεt that is subtracted before analysis of the Frεquenkursprekurums of the mean value of the recorded fuel pressure.
10. Vorrichtung zur Diagnose eines10. Device for diagnosing a
Kraftstoff ersorgungssystems einεr Brennkraftmaschine, dadurch gekennzeichnet, dass die Vorrichtung Mittel zur Durchführung des Verfahrεns nach εinem der Ansprüche 1 bis 9 aufweist. Fuel supply system of an internal combustion engine, characterized in that the device has means for carrying out the method according to one of claims 1 to 9.
EP00984821A 1999-10-19 2000-10-07 Method and device for the diagnosis of a fuel supply system Expired - Lifetime EP1226355B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19950222A DE19950222A1 (en) 1999-10-19 1999-10-19 Procedure for diagnosis of fuel supply system of IC engine has recording of variation of fuel pressure in system, formation of frequency spectrum of fuel pressure variation and analysis thereof
DE19950222 1999-10-19
PCT/DE2000/003531 WO2001029411A1 (en) 1999-10-19 2000-10-07 Method and device for the diagnosis of a fuel supply system

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EP1226355A1 true EP1226355A1 (en) 2002-07-31
EP1226355B1 EP1226355B1 (en) 2005-08-31

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EP (1) EP1226355B1 (en)
JP (1) JP2003512566A (en)
KR (1) KR100668576B1 (en)
DE (2) DE19950222A1 (en)
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EP1226355B1 (en) 2005-08-31
KR20020038957A (en) 2002-05-24
DE19950222A1 (en) 2001-04-26
US6901791B1 (en) 2005-06-07
KR100668576B1 (en) 2007-01-18
DE50011078D1 (en) 2005-10-06
JP2003512566A (en) 2003-04-02
WO2001029411A1 (en) 2001-04-26

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