EP2002110B1 - Method of preheating injectors of internal combustion engines - Google Patents

Method of preheating injectors of internal combustion engines Download PDF

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Publication number
EP2002110B1
EP2002110B1 EP20070701330 EP07701330A EP2002110B1 EP 2002110 B1 EP2002110 B1 EP 2002110B1 EP 20070701330 EP20070701330 EP 20070701330 EP 07701330 A EP07701330 A EP 07701330A EP 2002110 B1 EP2002110 B1 EP 2002110B1
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EP
European Patent Office
Prior art keywords
coil
current
electromagnet
preheating
valve
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EP20070701330
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German (de)
French (fr)
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EP2002110A1 (en
Inventor
Jaroslav Hlousek
Gerhard Rehbichler
Johannes Schnedt
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • 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
    • F02M51/00—Fuel-injection apparatus characterised by being operated electrically
    • F02M51/06—Injectors peculiar thereto with means directly operating the valve needle
    • F02M51/061—Injectors peculiar thereto with means directly operating the valve needle using electromagnetic operating means
    • 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
    • F02M53/00—Fuel-injection apparatus characterised by having heating, cooling or thermally-insulating means
    • F02M53/04—Injectors with heating, cooling, or thermally-insulating means
    • 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
    • F02M53/00—Fuel-injection apparatus characterised by having heating, cooling or thermally-insulating means
    • F02M53/04—Injectors with heating, cooling, or thermally-insulating means
    • F02M53/06—Injectors with heating, cooling, or thermally-insulating means with fuel-heating means, e.g. for vaporising
    • 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/24—Fuel-injection apparatus with sensors
    • F02M2200/248—Temperature sensors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T137/00—Fluid handling
    • Y10T137/6416—With heating or cooling of the system
    • Y10T137/6606—With electric heating element

Definitions

  • the invention relates to a method and a device for preheating at least one of a controllable by an electromagnet valve injection injectors of internal combustion engines, wherein the coil of the electromagnet is energized before starting the engine.
  • an injector for an injection system in particular for a common-rail diesel injection system consists of several parts, which are usually held together by a nozzle retaining nut.
  • a nozzle needle In the body of the actual injector nozzle, a nozzle needle is guided longitudinally displaceable, which has a plurality of open spaces over which fuel from the nozzle antechamber to the nozzle needle tip can flow.
  • At the nozzle needle tip is usually a sealing seat, which prevents the closed nozzle needle, that fuel enters the combustion chamber.
  • the nozzle needle has a collar on the circumference, on which a compression spring is supported, which acts closing on the nozzle needle.
  • the nozzle needle tip opposite end of the nozzle needle opens into a control chamber, which is acted upon by pressurized fuel.
  • At least one inlet channel and at least one outlet channel can be connected to this control chamber. All connected channels can have at least one throttle point.
  • the pressure in the control room can control a control valve, which usually operates a solenoid. When the valve is actuated, fuel can flow out of the control chamber so that the pressure drops there. Below an adjustable control chamber pressure, the fuel pressure at the sealing seat opens the nozzle needle, and fuel is injected into the combustion chamber via at least one injection hole. The flow rates through the individual choked channels determine the opening and closing speed of the nozzle needle.
  • the US 5201341 A shows and describes an electromagnetic valve for controlling a fluid flow, as can be used in Krafstoffinjektoren used in which the fuel to be heated by a fluctuating magnetic field, which is generated by the coil of an electromagnet, heated.
  • the DE 10100375 A1 shows and describes a method for operating a fuel oil burner with a nebulizer having a heated fuel oil by means of electrical energy heated nozzle assembly, in which by appropriate energization of the actuator of a solenoid valve, the heating energy is introduced to heat the fuel oil.
  • the heating is effected by the current supplied to the actuator both during the actuation phase of the solenoid valve and during the heating phase with the solenoid valve closed.
  • the solenoid on the fuel injector is in this case connected as a heating element, which on the one hand, an additional heating element can be saved, which saves costs and space, and on the other hand is ensured by the arrangement of the magnetic coils in the fuel injector that sets a rapid heating of the injector and thus rapid heating of the fuel flow from a fuel delivery system or a high-pressure collecting space flowing fuel volume.
  • the present invention therefore aims at starting from DE 4431189 A1 To provide a method for preheating the injection system, which is also suitable for highly viscous fuels such as heavy fuel injectors and which allows a control of the warm-up and the warm-up, so that it is ensured that the warm-up to a unimpaired operating state is made.
  • the inventive method is essentially characterized in that the coil of the electromagnet is periodically applied to a Voztage and that the current profile in the coil monitored and subjected to an evaluation for detecting caused by armature reactions local current minima and / or maxima ,
  • the electromagnet is preferably short-circuited and it is therefore provided according to a preferred procedure that the coil of the electromagnet is periodically applied alternately with a preheating and short-circuited.
  • the size of the preheat voltage is advantageously selected such that the valve closure member is moved before the current in the coil reaches a saturation level. More precise control can be achieved by selecting the magnitude of the preheat voltage such that the valve closure member reaches its maximum stroke before the current in the coil reaches a saturation level. When selecting such a preheating voltage can be determined from the observation of the current in the coil sure when the mobility of the valve closing member has reached a level that the maximum stroke can be traversed and thus a regular operation of the injection injector is ensured.
  • the valve closure member In order to ensure sufficient dynamics of the valve closure member, it is preferable to measure the time between the application of the preheating voltage to the coil and the occurrence of a current minimum caused by the armature reaction and to terminate the periodic application of the coil as soon as the measured period of time has become a defined nominal value below.
  • the detection of the time period between the application of the coil with the preheating voltage and the occurrence of a current minimum in the current of the coil allows the preheating to be carried out until the reduction of the viscosity of the fuel, and in particular of the heavy oil, to a sufficiently rapid operation, and in particular a sufficiently fast opening of the valve closure member leads.
  • a sufficient speed of this closing operation can then be determined, preferably by operating such that the time between the shorting of the coil and the occurrence of a current maximum caused by the armature reaction is measured and the periodic loading of the coil is terminated becomes as soon as the measured time span falls below a defined nominal dimension.
  • the temperature of the coil is monitored and the time intervals between the energization periods are regulated as a function of the temperature.
  • the temperature of the coil is calculated in a simple manner from the resistance of the coil.
  • FIG.1 and 2 the basic structure of an injector according to the prior art
  • Figure 3 a variant of the valve group for controlling the nozzle needle
  • Figure 4 shows an example of the current and voltage curve in the coil of the solenoid valve during the injection process.
  • Figure 5 Finally, a possible in the context of the present invention control of the solenoid valve for preheating the injection injector is shown.
  • an injection injector 1 which consists of an injector body 2, a valve group or a valve 3, an intermediate plate 4, an injector nozzle 5 and a nozzle retaining nut 6.
  • the injector nozzle 5 contains the nozzle needle 7, which is guided longitudinally displaceably in the injector nozzle 5 and has a plurality of free surfaces, via which fuel can flow from the nozzle front chamber 8 to the nozzle needle tip 9.
  • fuel is injected via at least one injection hole 10 into the combustion chamber 11.
  • a collar 12 is attached to the circumference, on which a compression spring 13 is supported, which exerts a closing force on the nozzle needle 7.
  • the nozzle needle 7 ends at the nozzle needle tip 9 opposite side with an end face 14 which ends in a control chamber 15.
  • the control chamber 15 has an inlet channel 16 with an inlet throttle 17 and an outlet channel 18 with an outlet throttle 19.
  • the flow rates through the inlet channel 16 and the outlet channel 18 are dimensioned so that the adjusting in the control chamber 15 pressure so is small that the nozzle needle 7 opens by the pending in the nozzle chamber 8 fuel pressure against the force of the compression spring 13 and against the pressure in the control chamber 15. If the drainage channel 18 is closed, the pressure in the control chamber 15 causes a force acting on the end face 14, which closes the nozzle needle 7.
  • the opening and closing speed of the nozzle needle 7 can be adjusted by a suitable choice of the throttle diameter.
  • the drainage channel 18 is closed with the valve needle 20 axially movable in the valve group 3.
  • the valve needle 20 is pressed by a valve spring 22 in the valve seat 23, which is designed as a sealing cone.
  • the valve seat 23 is released by the electromagnet 21 attracts the armature 25 and thereby moves the connected to the armature 25 valve needle 20, and the pressurized fuel flows from the drain passage 18 into the low-pressure chamber 27th
  • FIG. 3 shows a second possible formation of the valve group 3.
  • the drain channel 18 opens directly to the valve seat 23, which is closed by a valve ball 26.
  • the valve ball 26 is pressed by a valve spring 22 in the valve seat 23.
  • the electromagnet 21 When the electromagnet 21 is energized, it attracts the magnet armature 25 connected to the valve needle 20, the valve seat 23 is opened and the pressurized fuel flows from the outlet channel 18 into the low-pressure space 27.
  • Figure 4 shows the typical course of a current 33 and a voltage 34 in the winding of the electromagnet 21.
  • the control for the injection operation is characterized in that during an acceleration phase 28, the current through the electromagnet 21 monotonously increases until it reaches the upper limit of the attraction current 35th reached.
  • the current through the electromagnet 21 by means of a two-point current control between the upper limit of the attraction current 35 and the lower Limit value of the starting current 37 held.
  • the current through the electromagnet 21 in the freewheeling phase 30 decreases to the lower limit of the holding current 38.
  • the current through the electromagnet 21 is maintained by means of a two-point current control between the upper limit of the holding current 36 and the lower limit of the holding current 38.
  • the current through the electromagnet 21 in the quenching phase 32 is lowered back to zero.
  • a second possible current profile is now defined, with which a heating of the valve group 3 by the waste heat produced in the electromagnet 21 takes place, without thereby damaging the electromagnet 21.
  • the goal of this heating is to reduce the viscosity of the fuel, which is located in the cavities of the solenoid valve and the adjacent assemblies.
  • the necessary course of the current or current profile 33 in the electromagnet 21 is in Figure 5 shown.
  • the electromagnet 21 is periodically alternately subjected to a preheating voltage 42 alternately for the duration of the heating phase 41 and short-circuited between the energization periods for the duration of the freewheeling phase or time interval 30.
  • the duration of the heating phase 41 is chosen so that the inductance of the coil in the electromagnet 21 can be neglected.
  • the size of the preheat voltage 42 is selected so that the valve needle 20 reaches its maximum stroke before the current 33 reaches the saturation level 45 through the electromagnet 21.
  • the temperature of the coil of the electromagnet 21 can be calculated from the known temperature dependence of the electrical resistance. The change in the electrical resistance of the coil is determined by measuring the difference in voltage or current before and during the heating.
  • the warm-up phase is ended when the valve needle 20 is movable and during the warm-up phase 39 due to the armature reaction, a local current minimum 43 when opening the valve needle 20 and a local current maximum 44 when closing the valve needle 20 is detected. If, on the other hand, no armature reactions can still be detected during the warm-up phase 39 and the measured resistance is greater than the maximum permissible resistance setpoint, ie the temperature reaches or exceeds the permissible level, the warm-up phase 39 is ended and the temperature regulation phase 40 begins.
  • the temperature control phase 40 differs from the warm-up phase 39 in that one or more cycles of heating phase 41 and freewheeling phase 30 are omitted.
  • the number of cycles to be eliminated is determined from the deviation from the nominal resistance to the measured resistance in the electromagnet 21, so that the predetermined temperature is not exceeded.
  • the temperature control phase is terminated when in turn due to the armature reaction, a local current minimum 43 when opening the valve needle 20 and a local current maximum 44 when closing the valve needle 20 is detected.
  • An improvement of the method is achieved in that in addition the time period 46 between the start of the energization of the electromagnet 21 and the occurrence of the local current minimum 43 and the time period 47 between the end of the energization and the occurrence of the local current maximum 44 is determined and the inventive periodic Energization of the electromagnet 21 is only terminated when the period 46 or 47 falls below a target value, which means that the nozzle needle has sufficient dynamics, so can be opened or closed sufficiently quickly.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Fuel-Injection Apparatus (AREA)
  • Magnetically Actuated Valves (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

The method involves energizing a coil of an electromagnet before starting an internal combustion engine, where the electromagnet is provided for activating a valve of a fuel injector. A preheating voltage (42) is periodically applied to the coil of the electromagnet. Current characteristic (33) in the coil is monitored and evaluated for detecting local current minima (43) and/or current maxima (44) that are caused by armature reactions. An independent claim is also included for a device for preheating a fuel injector of an internal combustion engine.

Description

Die Erfindung betrifft ein Verfahren sowie eine Vorrichtung zur Vorwärmung von wenigstens einem ein durch einen Elektromagneten ansteuerbares Ventil aufweisenden Einspritzinjektoren von Brennkraftmaschinen, bei welchem vor dem Motorstart die Spule des Elektromagneten bestromt wird.The invention relates to a method and a device for preheating at least one of a controllable by an electromagnet valve injection injectors of internal combustion engines, wherein the coil of the electromagnet is energized before starting the engine.

Grundsätzlich besteht ein Injektor für ein Einspritzsystem, insbesondere für ein Common-Rail-Dieseleinspritzsystem aus mehreren Teilen, die in der Regel von einer Düsenspannmutter zusammen gehalten werden. Im Körper der eigentlichen Injektordüse ist eine Düsennadel längsverschieblich geführt, die mehrere Freiflächen aufweist, über die aus dem Düsenvorraum Kraftstoff zur Düsennadelspitze strömen kann. An der Düsennadelspitze befindet sich in der Regel ein Dichtsitz, der bei geschlossener Düsennadel verhindert, dass Kraftstoff in den Brennraum gelangt. Die Düsennadel besitzt am Umfang einen Bund, auf dem sich eine Druckfeder abstützt, die schließend auf die Düsennadel wirkt. Das der Düsennadelspitze entgegengesetzte Ende der Düsennadel mündet in einen Steuerraum, der mit unter Druck stehendem Kraftstoff beaufschlagbar ist. An diesen Steuerraum können mindestens ein Zulaufkanal und mindestens ein Ablaufkanal angeschlossen sein. Alle angeschlossenen Kanäle können mindestens eine Drosselstelle aufweisen. Den Druck im Steuerraum kann ein Steuerventil kontrollieren, das meist ein Elektromagnet betätigt. Bei Betätigen des Ventils kann Kraftstoff aus dem Steuerraum abfließen, sodass dort der Druck sinkt. Unterhalb eines einstellbaren Steuerraumdrucks öffnet der Kraftstoffdruck am Dichtsitz die Düsennadel, und Kraftstoff wird über mindestens ein Spritzloch in den Brennraum eingespritzt. Die Durchflussmengen durch die einzelnen mit Drosseln versehenen Kanäle bestimmen dabei die Öffnungs- und die Schließgeschwindigkeit der Düsennadel.Basically, an injector for an injection system, in particular for a common-rail diesel injection system consists of several parts, which are usually held together by a nozzle retaining nut. In the body of the actual injector nozzle, a nozzle needle is guided longitudinally displaceable, which has a plurality of open spaces over which fuel from the nozzle antechamber to the nozzle needle tip can flow. At the nozzle needle tip is usually a sealing seat, which prevents the closed nozzle needle, that fuel enters the combustion chamber. The nozzle needle has a collar on the circumference, on which a compression spring is supported, which acts closing on the nozzle needle. The nozzle needle tip opposite end of the nozzle needle opens into a control chamber, which is acted upon by pressurized fuel. At least one inlet channel and at least one outlet channel can be connected to this control chamber. All connected channels can have at least one throttle point. The pressure in the control room can control a control valve, which usually operates a solenoid. When the valve is actuated, fuel can flow out of the control chamber so that the pressure drops there. Below an adjustable control chamber pressure, the fuel pressure at the sealing seat opens the nozzle needle, and fuel is injected into the combustion chamber via at least one injection hole. The flow rates through the individual choked channels determine the opening and closing speed of the nozzle needle.

Wird ein derartiger Injektor mit hochviskosen Kraftstoffen - beispielsweise Schweröl - betrieben, kann es notwendig sein, den Kraftstoff zu erwärmen, um die notwendige Einspritzviskosität zu erreichen. Es ist daher üblich, bei Verwendung von derartigen Kraftstoffen das Einspritzsystem vor Abstellen des Motors mit einem zweiten Kraftstoff geringer Viskosität - beispielsweise Dieselöl - zu spülen. Dadurch wird verhindert, dass hochviskoser Kraftstoff im Injektor abkühlt und die Funktion des Einspritzsystems während des Motorstarts beeinträchtigt oder gar unmöglich macht.If such an injector operated with highly viscous fuels - such as heavy oil - it may be necessary to heat the fuel in order to achieve the necessary injection viscosity. It is therefore common, when using such fuels, the injection system before stopping the engine with a second fuel low viscosity - to rinse - for example, diesel oil. This prevents high-viscosity fuel in the injector from cooling down and impairing the function of the injection system during engine start-up or even making it impossible.

Die US 5201341 A zeigt und beschreibt ein elektromagnetisches Ventil zur Kontrolle eines Fluidstroms, wie es bei Krafstoffinjektoren zum Einsatz gelangen kann, bei welchem der aufzuheizende Kraftstoff von einem fluktuierenden Magnetfeld, welches durch die Spule eines Elektromagneten erzeugt wird, aufgeheizt wird.The US 5201341 A shows and describes an electromagnetic valve for controlling a fluid flow, as can be used in Krafstoffinjektoren used in which the fuel to be heated by a fluctuating magnetic field, which is generated by the coil of an electromagnet, heated.

Die DE 10100375 A1 zeigt und beschreibt ein Verfahren zum Betreiben eines Heizölbrenners mit einer Zerstäubereinrichtung, die einen von Heizöl durchströmten mittels elektrischer Energie beheizbaren Düsenstock aufweist, bei welchem durch geeignete Bestromung der Aktuatorspule eines Magnetventils die Heizenergie zur Aufheizung des Heizöls eingeleitet wird. Bei diesem Verfahren erfolgt die Beheizung durch den dem Aktuator zugeführten Strom sowohl während der Betätigungsphase des Magnetventils als auch während der Aufheizphase bei geschlossenem Magnetventil.The DE 10100375 A1 shows and describes a method for operating a fuel oil burner with a nebulizer having a heated fuel oil by means of electrical energy heated nozzle assembly, in which by appropriate energization of the actuator of a solenoid valve, the heating energy is introduced to heat the fuel oil. In this method, the heating is effected by the current supplied to the actuator both during the actuation phase of the solenoid valve and during the heating phase with the solenoid valve closed.

Aus der DE 10136049 A1 ist ein Verfahren zur Erwärmung von Kraftstoff in einem eine oder mehrere Magnetspulen enthaltenden Kraftstoffinjektor bekannt geworden, bei dem die Injektormagnetspule eines Kraftstoffinjektors zur Aufheizung des Kraftstoffs genutzt wird. Das in dieser Literaturstelle vorgeschlagene Verfahren lässt sich sowohl bei solchen Krafstoffinjektoren, die eine einspulige Magnetanordnung aufweisen, einsetzten als auch bei solchen Kraftstoffinjektoren, die eine doppelspulige Magnetanordnung zur Ansteuerung des Kraftstoffeinspritzventils aufweisen. Die Magnetspule am Kraftstoffinjektor wird hierbei als Heizelement geschaltet, wodurch einerseits ein zusätzliches Heizelement eingespart werden kann, was Kosten und Bauraum spart, und andererseits durch die Anordnung der Magnetspulen im Kraftstoffinjektor gewährleistet ist, dass sich eine schnelle Erwärmung des Injektorkörpers einstellt und damit eine rasche Erwärmung des von einer Kraftstoffförderanlage oder eines Hochdrucksammelraums zufließenden Kraftstoffvolumens erfolgt.From the DE 10136049 A1 For example, there has been known a method of heating fuel in a fuel injector including one or more solenoids wherein the injector solenoid of a fuel injector is used to heat the fuel. The method proposed in this reference can be used both in such Krafstoffinjektoren having a einspulige magnet arrangement, as well as in such fuel injectors, the one Have double-coil magnet arrangement for controlling the fuel injection valve. The solenoid on the fuel injector is in this case connected as a heating element, which on the one hand, an additional heating element can be saved, which saves costs and space, and on the other hand is ensured by the arrangement of the magnetic coils in the fuel injector that sets a rapid heating of the injector and thus rapid heating of the fuel flow from a fuel delivery system or a high-pressure collecting space flowing fuel volume.

Aus der DE 4431189 A1 ist ein Verfahren zum Vorwärmen des Kraftstoffs für Brennkraftmaschinen bekannt, bei dem mittels eines elektrisch betätigten Einspritzventils für den Kraftstoff bei kaltem Kraftstoff die elektrische Verlustleistung der elektrischen Betätigung erhöht und deren Abwärme zum Vorwärmen des Kraftstoffs eingesetzt wird. Mittels des vorgeschlagenen Verfahrens wird als Ersatz für gesonderte elektrische Heizelemente vorgeschlagen, bei Motoren mit elektrisch bzw. elektromagnetisch betätigten Einspritzdüsen die Wärmeenergie zur Beheizung des Kraftstoffs über eine künstliche Erhöhung der Energiezufuhr zur elektrischen bzw. elektromagnetischen Ventilbetätigung der Einspritzventile zuzuführen. Dies kann beispielsweise dadurch erfolgen, dass beim Öffnen der Fahrzeugtür ein elektrischer Kontakt geschlossen wird, welcher in Abhängigkeit von der Umgebungs- und Rühlmitteltemperatur für eine definierte Zeit oder bis zum Erreichen einer definierten Kraftstofftemperatur einen elektrischen Strom durch die Wicklungen von Einspritzdüsen strömen lässt. Dabei ist sichergestellt, dass trotz dieser Maßnahmen noch kein Kraftstoff zur Einspritzung gelangt.From the DE 4431189 A1 A method of preheating the fuel for internal combustion engines is known in which by means of an electrically operated injection valve for the fuel with cold fuel increases the electrical power loss of electrical operation and the waste heat is used to preheat the fuel. By means of the proposed method is proposed as a substitute for separate electrical heating elements to supply in engines with electrically or electromagnetically actuated injectors, the heat energy for heating the fuel via an artificial increase in the power supply to the electric or electromagnetic valve actuation of the injectors. This can be done, for example, that when opening the vehicle door, an electrical contact is closed, which flows depending on the ambient and Rühlmitteltemperatur for a defined time or until reaching a defined fuel temperature, an electric current through the windings of injectors. It is ensured that, despite these measures, no fuel yet comes to the injection.

Allerdings ist bei dem aus der DE 4431189 A1 bekannt gewordenen Verfahren keinesfalls sichergestellt, dass auch hochviskose Kraftstoffe, wie beispielsweise Schweröl, ausreichend aufgewärmt werden, dass eine für die Einspritzung erforderliche Reduktion der Viskosität erfolgt. Insbesondere ist keine Kontrolle vorgesehen, ob die Aufwärmung des Injektors tatsächlich zu dem gewünschten Ergebnis führt, nämlich, dass das Ventilschließglied frei und ohne Behinderung durch zähflüssiges Schweröl beweglich ist.However, in the case of the DE 4431189 A1 have become known processes by no means ensured that even highly viscous fuels, such as heavy oil, are sufficiently warmed up that a required for the injection reduction of the viscosity takes place. In particular, none Control provided whether the warming of the injector actually leads to the desired result, namely, that the valve closure member is free and movable without obstruction by viscous heavy oil.

Die vorliegende Erfindung zielt daher ausgehend von der DE 4431189 A1 darauf ab, ein Verfahren zur Vorwärmung des Einspritzsystems zu schaffen, welches auch für mit hochviskosen Kraftstoffen, wie beispielsweise mit Schweröl, betriebene Injektoren geeignet ist und welches eine Regelung der Aufwärmzeit und der Aufwärmtemperatur erlaubt, sodass sichergestellt ist, dass die Aufwärmung bis zur Erreichung eines unbeeinträchtigen Betriebszustandes vorgenommen wird.The present invention therefore aims at starting from DE 4431189 A1 To provide a method for preheating the injection system, which is also suitable for highly viscous fuels such as heavy fuel injectors and which allows a control of the warm-up and the warm-up, so that it is ensured that the warm-up to a unimpaired operating state is made.

Zur Lösung dieser Aufgabe ist das erfindungsgemäße Verfahren im Wesentlichen dadurch gekennzeichnet, dass die Spule des Elektromagneten periodisch mit einer Vozwärmespannung beaufschlagt wird und dass der Stromverlauf in der Spule überwacht und einer Auswertung zur Erkennung von durch Ankerrückwirkungen bewirkten lokalen Stromminima und/oder -maxima unterzogen wird. Durch eine derartige Vorgangsweise kann bei jedem der periodisch vorgenommenen Bestromungsvorgänge eine Überwachung erfolgen, ob die Vorwärmung des Einspritzinjektors bereits zu einer derartigen Reduktion der Viskosität geführt hat, dass das Ventilschließglied des Magnetventils frei bewegbar ist. Die Bewegbarkeit des Ventilschließglieds wird hierbei anhand der Ankerrückwirkungen erkannt, wobei die Ankerrückwirkungen durch lokale Stromminima und/oder Strommaxima erkennbar sind. Auf dieser Basis kann eine präzise Steuerung des Aufwärmvorgangs vorgenommen werden, wobei gleichzeitig eine Überhitzung vermieden werden kann. Im Anschluss an jeden der periodisch vorgenommenen Bestromungsvorgänge wird bevorzugt der Elektromagnet kurzgeschlossen und es ist daher gemäß einer bevorzugten Verfahrensweise vorgesehen, dass die Spule des Elektromagneten periodisch abwechselnd mit einer Vorwärmespannung beaufschlagt und kurzgeschlossen wird.To solve this problem, the inventive method is essentially characterized in that the coil of the electromagnet is periodically applied to a Vozwärmespannung and that the current profile in the coil monitored and subjected to an evaluation for detecting caused by armature reactions local current minima and / or maxima , By such a procedure can take place in each of the periodically performed Bestromungsvorgänge monitoring whether the preheating of the injection injector has already led to such a reduction in viscosity that the valve-closing member of the solenoid valve is freely movable. The mobility of the valve closure member is in this case recognized on the basis of the armature reactions, wherein the armature reactions can be detected by local current minima and / or current maxima. On this basis, a precise control of the warm-up process can be made while avoiding overheating. Following each of the periodically performed Bestromungsvorgänge the electromagnet is preferably short-circuited and it is therefore provided according to a preferred procedure that the coil of the electromagnet is periodically applied alternately with a preheating and short-circuited.

Um sicherzustellen, dass die Bewegbarkeit des Ventilschließglieds auf Grund der Ankerrückwirkungen erkennbar ist, wird mit Vorteil die Größe der Vorwärmespannung derart gewählt, dass das Ventilschließglied bewegt wird, bevor der Strom in der Spule ein Sättigungsniveau erreicht. Eine präzisere Steuerung kann dadurch erreicht werden, dass die Größe der Vorwärmespannung derart gewählt wird, dass das Ventilschließglied seinen maximalen Hub erreicht, bevor der Strom in der Spule ein Sättigungsniveau erreicht. Bei Wahl einer derartigen Vorwärmespannung kann anhand der Beobachtung des Stroms in der Spule sicher festgestellt werden, wann die Beweglichkeit des Ventilschließglieds ein Ausmaß erreicht hat, dass der maximale Hub durchfahren werden kann und somit eine reguläre Betriebsweise des Einspritzinjektors gewährleistet ist.To ensure that the movability of the valve closure member is recognizable due to the armature feedback, the size of the preheat voltage is advantageously selected such that the valve closure member is moved before the current in the coil reaches a saturation level. More precise control can be achieved by selecting the magnitude of the preheat voltage such that the valve closure member reaches its maximum stroke before the current in the coil reaches a saturation level. When selecting such a preheating voltage can be determined from the observation of the current in the coil sure when the mobility of the valve closing member has reached a level that the maximum stroke can be traversed and thus a regular operation of the injection injector is ensured.

Um eine ausreichende Dynamik des Ventilschließglieds sicherzustellen wird bevorzugt derart vorgegangen, dass die Zeitspanne zwischen der Beaufschlagung der Spule mit der Vorwärmespannung und dem Auftreten eines durch die Ankerrückwirkung bewirkten Stromminimums gemessen wird und die periodische Beaufschlagung der Spule beendet wird, sobald die gemessene Zeitspanne ein definiertes Sollmaß unterschreitet. Die Erfassung der Zeitspanne zwischen der Beaufschlagung der Spule mit der Vorwärmespannung und dem Auftreten eines Stromminimums im Strom der Spule erlaubt es die Vorwärmung solange durchzuführen, bis die Reduktion der Viskosität des Kraftstoffs, und insbesondere des Schweröls, zu einer ausreichend schnellen Betätigung, und insbesondere zu einem ausreichend schnellen Öffnen des Ventilschließglieds, führt. Was den Schließvorgang des Ventilschließglieds betrifft, so kann eine ausreichende Geschwindigkeit dieses Schließvorgangs dann festgestellt werden, wenn bevorzugt derart vorgegangen wird, dass die Zeitspanne zwischen dem Kurzschließen der Spule und dem Auftreten eines durch die Ankerrückwirkung bewirkten Strommaximums gemessen wird und die periodische Beaufschlagung der Spule beendet wird, sobald die gemessen Zeitspanne ein definiertes Sollmaß unterschreitet.In order to ensure sufficient dynamics of the valve closure member, it is preferable to measure the time between the application of the preheating voltage to the coil and the occurrence of a current minimum caused by the armature reaction and to terminate the periodic application of the coil as soon as the measured period of time has become a defined nominal value below. The detection of the time period between the application of the coil with the preheating voltage and the occurrence of a current minimum in the current of the coil allows the preheating to be carried out until the reduction of the viscosity of the fuel, and in particular of the heavy oil, to a sufficiently rapid operation, and in particular a sufficiently fast opening of the valve closure member leads. As regards the closing action of the valve closing member, a sufficient speed of this closing operation can then be determined, preferably by operating such that the time between the shorting of the coil and the occurrence of a current maximum caused by the armature reaction is measured and the periodic loading of the coil is terminated becomes as soon as the measured time span falls below a defined nominal dimension.

Um eine Überhitzung der Spule durch eine zu rasche Abfolge der periodisch eingeleiteten Bestromungsvorgänge zu verhindern, wird bevorzugt derart vorgegangen, dass die Temperatur der Spule überwacht wird und die Zeitabstände zwischen den Bestromungsperioden in Abhängigkeit von der Temperatur geregelt werden. Hierbei wird die Temperatur der Spule in einfacher Weise aus dem Widerstand der Spule errechnet.In order to prevent overheating of the coil by an excessively rapid sequence of the periodically initiated energizing processes, it is preferred to proceed in such a way that the temperature of the coil is monitored and the time intervals between the energization periods are regulated as a function of the temperature. Here, the temperature of the coil is calculated in a simple manner from the resistance of the coil.

Die Erfindung wird nachfolgend anhand eines in der Zeichnung schematisch dargestellten Ausführungsbeispiels näher erläutert. In dieser zeigen Fig.1 und 2 den grundsätzlichen Aufbau eines Injektors gemäß dem Stand der Technik, Fig.3 eine Ausführungsvariante der Ventilgruppe zur Steuerung der Düsennadel, Fig.4 zeigt beispielhaft den Strom- und Spannungsverlauf in der Spule des Magnetventils während des Einspritzvorgangs. In Fig.5 schließlich ist eine im Rahmen der vorliegenden Erfindung mögliche Ansteuerung des Magnetventils zur Vorwärmung des Einspritzinjektors dargestellt.The invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawing. In this show Fig.1 and 2 the basic structure of an injector according to the prior art, Figure 3 a variant of the valve group for controlling the nozzle needle, Figure 4 shows an example of the current and voltage curve in the coil of the solenoid valve during the injection process. In Figure 5 Finally, a possible in the context of the present invention control of the solenoid valve for preheating the injection injector is shown.

In den Fig. 1 und 2 ist ein Einspritzinjektor 1 dargestellt, der aus einem Injektorkörper 2, einer Ventilgruppe bzw. einem Ventil 3, einer Zwischenplatte 4, einer Injektordüse 5 und einer Düsenspannmutter 6 besteht. Die Injektordüse 5 enthält die Düsennadel 7, die in der Injektordüse 5 längsverschieblich geführt ist und mehrere Freiflächen aufweist, über die Kraftstoff vom Düsenvorraum 8 zur Düsennadelspitze 9 strömen kann. Bei Öffnung der Düsennadel 7 wird Kraftstoff über mindestens ein Spritzloch 10 in den Brennraum 11 eingespritzt. An der Düsennadel 7 ist am Umfang ein Bund 12 angebracht, an dem sich eine Druckfeder 13 abstützt, die eine schließende Kraft auf die Düsennadel 7 ausübt. Die Düsennadel 7 endet an der der Düsennadelspitze 9 gegenüberliegenden Seite mit einer Stirnfläche 14, die in einem Steuerraum 15 endet. Der Steuerraum 15 besitzt einen Zulaufkanal 16 mit einer Zulaufdrossel 17 und einen Ablaufkanal 18 mit einer Ablaufdrossel 19. Die Durchflussmengen durch Zulaufkanal 16 und Ablaufkanal 18 sind so bemessen, dass der sich im Steuerraum 15 einstellende Druck so klein ist, dass die Düsennadel 7 durch den im Düsenvorraum 8 anstehenden Kraftstoffdruck gegen die Kraft der Druckfeder 13 und gegen den Druck im Steuerraum 15 öffnet. Wird der Ablaufkanal 18 verschlossen, bewirkt der Druck im Steuerraum 15 eine auf die Stirnfläche 14 wirkende Kraft, welche die Düsennadel 7 schließt. Die Öffnungs- und Schließgeschwindigkeit der Düsennadel 7 kann durch geeignete Wahl der Drosseldurchmesser eingestellt werden. Der Ablaufkanal 18 wird mit der in der Ventilgruppe 3 axial beweglichen Ventilnadel 20 verschlossen. Die Ventilnadel 20 wird von einer Ventilfeder 22 in den Ventilsitz 23 gedrückt, der als Dichtkonus ausgebildet ist. Bei Bestromung des Elektromagneten 21 wird der Ventilsitz 23 freigegeben, indem der Elektromagnet 21 den Magnetanker 25 anzieht und dadurch die mit dem Magnetanker 25 verbundene Ventilnadel 20 bewegt, und der unter Druck stehende Kraftstoff strömt vom Ablaufkanal 18 in den Niederdruckraum 27.In the Fig. 1 and 2 an injection injector 1 is shown which consists of an injector body 2, a valve group or a valve 3, an intermediate plate 4, an injector nozzle 5 and a nozzle retaining nut 6. The injector nozzle 5 contains the nozzle needle 7, which is guided longitudinally displaceably in the injector nozzle 5 and has a plurality of free surfaces, via which fuel can flow from the nozzle front chamber 8 to the nozzle needle tip 9. Upon opening of the nozzle needle 7, fuel is injected via at least one injection hole 10 into the combustion chamber 11. At the nozzle needle 7 a collar 12 is attached to the circumference, on which a compression spring 13 is supported, which exerts a closing force on the nozzle needle 7. The nozzle needle 7 ends at the nozzle needle tip 9 opposite side with an end face 14 which ends in a control chamber 15. The control chamber 15 has an inlet channel 16 with an inlet throttle 17 and an outlet channel 18 with an outlet throttle 19. The flow rates through the inlet channel 16 and the outlet channel 18 are dimensioned so that the adjusting in the control chamber 15 pressure so is small that the nozzle needle 7 opens by the pending in the nozzle chamber 8 fuel pressure against the force of the compression spring 13 and against the pressure in the control chamber 15. If the drainage channel 18 is closed, the pressure in the control chamber 15 causes a force acting on the end face 14, which closes the nozzle needle 7. The opening and closing speed of the nozzle needle 7 can be adjusted by a suitable choice of the throttle diameter. The drainage channel 18 is closed with the valve needle 20 axially movable in the valve group 3. The valve needle 20 is pressed by a valve spring 22 in the valve seat 23, which is designed as a sealing cone. Upon energization of the electromagnet 21, the valve seat 23 is released by the electromagnet 21 attracts the armature 25 and thereby moves the connected to the armature 25 valve needle 20, and the pressurized fuel flows from the drain passage 18 into the low-pressure chamber 27th

Fig.3 zeigt eine zweite mögliche Ausbildung der Ventilgruppe 3. Der Ablaufkanal 18 mündet direkt beim Ventilsitz 23, der mit einer Ventilkugel 26 verschlossen wird. Die Ventilkugel 26 wird von einer Ventilfeder 22 in den Ventilsitz 23 gedrückt. Bei Bestromung des Elektromagneten 21 zieht dieser den mit der Ventilnadel 20 verbundenen Magnetanker 25 an, der Ventilsitz 23 wird geöffnet und der unter Druck stehende Kraftstoff strömt vom Ablaufkanal 18 in den Niederdruckraum 27. Figure 3 shows a second possible formation of the valve group 3. The drain channel 18 opens directly to the valve seat 23, which is closed by a valve ball 26. The valve ball 26 is pressed by a valve spring 22 in the valve seat 23. When the electromagnet 21 is energized, it attracts the magnet armature 25 connected to the valve needle 20, the valve seat 23 is opened and the pressurized fuel flows from the outlet channel 18 into the low-pressure space 27.

Fig.4 zeigt den typischen Verlauf eines Stromes 33 bzw. einer Spannung 34 in der Wicklung des Elektromagneten 21. Die Ansteuerung für den Einspritzbetrieb ist dadurch gekennzeichnet, dass während einer Beschleunigungsphase 28 der Strom durch den Elektromagneten 21 monoton ansteigt, bis er den oberen Grenzwert des Anzugsstroms 35 erreicht. In der folgenden Anzugsstromphase 29, während der sich der Magnetanker 25 als Folge der vom Elektromagneten 21 verursachten Magnetkraft gegen die Kraft der Ventilfeder 22 bewegt, wird der Strom durch den Elektromagneten 21 mit Hilfe einer Zweipunktstromregelung zwischen dem oberen Grenzwert des Anzugsstroms 35 und dem unteren Grenzwert des Anzugsstroms 37 gehalten. Nach Öffnen der Ventilgruppe 3 sinkt der Strom durch den Elektromagneten 21 in der Freilaufphase 30 auf den unteren Grenzwert des Haltestroms 38 ab. Bis zum Ende der nun folgenden Haltestromphase 31 wird der Strom durch den Elektromagneten 21 mittels einer Zweipunktstromregelung zwischen dem oberen Grenzwert des Haltestroms 36 und dem unteren Grenzwert des Haltestroms 38 gehalten. Zum Schließen der Ventilgruppe 3 wird der Strom durch den Elektromagneten 21 in der Löschphase 32 wieder auf Null abgesenkt. Figure 4 shows the typical course of a current 33 and a voltage 34 in the winding of the electromagnet 21. The control for the injection operation is characterized in that during an acceleration phase 28, the current through the electromagnet 21 monotonously increases until it reaches the upper limit of the attraction current 35th reached. In the following starting current phase 29, during which the magnet armature 25 moves as a result of the magnetic force caused by the electromagnet 21 against the force of the valve spring 22, the current through the electromagnet 21 by means of a two-point current control between the upper limit of the attraction current 35 and the lower Limit value of the starting current 37 held. After opening the valve group 3, the current through the electromagnet 21 in the freewheeling phase 30 decreases to the lower limit of the holding current 38. Until the end of the following holding current phase 31, the current through the electromagnet 21 is maintained by means of a two-point current control between the upper limit of the holding current 36 and the lower limit of the holding current 38. To close the valve group 3, the current through the electromagnet 21 in the quenching phase 32 is lowered back to zero.

Im Rahmen der gegenständlichen Erfindung wird nun ein zweiter möglicher Stromverlauf definiert, mit dem eine Erwärmung der Ventilgruppe 3 durch die im Elektromagneten 21 produzierte Abwärme erfolgt, ohne dadurch den Elektromagneten 21 zu schädigen. Das Ziel dieser Erwärmung ist die Verringerung der Viskosität des Kraftstoffs, der sich in den Hohlräumen des Magnetventils und der benachbarten Baugruppen befindet. Der dazu notwendige Verlauf des Stromes bzw. Stromverlauf 33 im Elektromagneten 21 ist in Fig.5 dargestellt. Während der Aufwärmphase 39 wird der Elektromagnet 21 periodisch abwechselnd für die Dauer der Heizphase 41 mit einer Vorwärmspannung 42 beaufschlagt und für die Dauer der Freilaufphase bzw. Zeitabstand 30 zwischen den Bestromungsperioden kurzgeschlossen. Die Dauer der Heizphase 41 wird so gewählt, dass die Induktivität der Spule im Elektromagneten 21 vernachlässigt werden kann. Die Größe der Vorwärmspannung 42 wird so gewählt, dass die Ventilnadel 20 ihren maximalen Hub erreicht, bevor der Strom 33 durch den Elektromagneten 21 das Sättigungsniveau 45 erreicht. Dadurch sind im Verlauf des Stromes 33 bei Öffnen und Schließen der Ventilnadel Ankerrückwirkungen erkennbar, sobald die Ventilnadel 20 beweglich wird. Die Temperatur der Spule des Elektromagneten 21 kann aus der bekannten Temperaturabhängigkeit des elektrischen Widerstands berechnet werden. Die Änderung des elektrischen Widerstands der Spule wird durch Messung der Differenz von Spannung bzw. Strom vor und während der Aufwärmung ermittelt. Die Aufwärmphase wird beendet wenn die Ventilnadel 20 beweglich ist und während der Aufwärmphase 39 aufgrund der Ankerrückwirkung ein lokales Stromminimum 43 beim Öffnen der Ventilnadel 20 und ein lokales Strommaximum 44 beim Schließen der Ventilnadel 20 festgestellt wird. Wenn hingegen während der Aufwärmphase 39 noch keine Ankerrückwirkungen feststellbar sind und der gemessene Widerstand größer ist als der maximal erlaubte Widerstandsollwert, die Temperatur also das zulässige Maß erreicht bzw. überschreitet, wird die Aufwärmphase 39 beendet und die Temperaturregelphase 40 beginnt. Die Temperaturregelphase 40 unterscheidet sich von der Aufwärmphase 39 dadurch, dass ein oder mehrere Zyklen aus Heizphase 41 und Freilaufphase 30 entfallen. Die Anzahl der zu entfallenden Zyklen wird dabei aus der Abweichung vom Sollwiderstand zum gemessenen Widerstand im Elektromagneten 21 ermittelt, sodass die vorgegebene Temperatur nicht überschritten wird. Die Temperaturregelphase wird beendet, wenn wiederum aufgrund der Ankerrückwirkung ein lokales Stromminimum 43 beim Öffnen der Ventilnadel 20 und ein lokales Strommaximum 44 beim Schließen der Ventilnadel 20 festgestellt wird.In the context of the present invention, a second possible current profile is now defined, with which a heating of the valve group 3 by the waste heat produced in the electromagnet 21 takes place, without thereby damaging the electromagnet 21. The goal of this heating is to reduce the viscosity of the fuel, which is located in the cavities of the solenoid valve and the adjacent assemblies. The necessary course of the current or current profile 33 in the electromagnet 21 is in Figure 5 shown. During the warm-up phase 39, the electromagnet 21 is periodically alternately subjected to a preheating voltage 42 alternately for the duration of the heating phase 41 and short-circuited between the energization periods for the duration of the freewheeling phase or time interval 30. The duration of the heating phase 41 is chosen so that the inductance of the coil in the electromagnet 21 can be neglected. The size of the preheat voltage 42 is selected so that the valve needle 20 reaches its maximum stroke before the current 33 reaches the saturation level 45 through the electromagnet 21. As a result, in the course of the current 33 upon opening and closing of the valve needle armature reactions can be seen as soon as the valve needle 20 is movable. The temperature of the coil of the electromagnet 21 can be calculated from the known temperature dependence of the electrical resistance. The change in the electrical resistance of the coil is determined by measuring the difference in voltage or current before and during the heating. The warm-up phase is ended when the valve needle 20 is movable and during the warm-up phase 39 due to the armature reaction, a local current minimum 43 when opening the valve needle 20 and a local current maximum 44 when closing the valve needle 20 is detected. If, on the other hand, no armature reactions can still be detected during the warm-up phase 39 and the measured resistance is greater than the maximum permissible resistance setpoint, ie the temperature reaches or exceeds the permissible level, the warm-up phase 39 is ended and the temperature regulation phase 40 begins. The temperature control phase 40 differs from the warm-up phase 39 in that one or more cycles of heating phase 41 and freewheeling phase 30 are omitted. The number of cycles to be eliminated is determined from the deviation from the nominal resistance to the measured resistance in the electromagnet 21, so that the predetermined temperature is not exceeded. The temperature control phase is terminated when in turn due to the armature reaction, a local current minimum 43 when opening the valve needle 20 and a local current maximum 44 when closing the valve needle 20 is detected.

Eine Verbesserung des Verfahrens gelingt dadurch, dass zusätzlich die Zeitspanne 46 zwischen dem Beginn der Bestromung des Elektromagneten 21 und dem Auftreten des lokalen Stromminimums 43 bzw. die Zeitspanne 47 zwischen dem Ende der Bestromung und dem Auftreten des lokalen Strommaximums 44 ermittelt wird und die erfindungsgemäße periodische Bestromung des Elektromagneten 21 erst dann beendet wird, wenn die Zeitspanne 46 bzw. 47 einen Sollwert unterschreitet, was bedeutet, dass die Düsennadel eine ausreichende Dynamik aufweist, also ausreichend schnell geöffnet bzw. geschlossen werden kann.An improvement of the method is achieved in that in addition the time period 46 between the start of the energization of the electromagnet 21 and the occurrence of the local current minimum 43 and the time period 47 between the end of the energization and the occurrence of the local current maximum 44 is determined and the inventive periodic Energization of the electromagnet 21 is only terminated when the period 46 or 47 falls below a target value, which means that the nozzle needle has sufficient dynamics, so can be opened or closed sufficiently quickly.

Sobald also während der Heizphase 41 ein lokales Stromminimum 43 bei Öffnen und während der folgenden Freilaufphase 30 ein lokales Strommaximum 44 beim Schließen auftritt und diese zeitlich innerhalb vordefinierter Grenzen liegen, kann daraus geschlossen werden, dass die Ventilnadel 20 in der Ventilgruppe 3 beweglich ist, und damit eine ordnungsgemäße Einspritzung erfolgen kann. In diesem Fall erfolgt die Umschaltung zwischen Vorwärmung (Fig.5) und regulärer Ansteuerung (Fig.4).As soon as, during the heating phase 41, a local current minimum 43 during opening and during the following freewheeling phase 30, a local maximum current 44 occurs when closing and these are within predefined limits, it can be concluded that the valve needle 20 is movable in the valve group 3, and thus a proper injection can be done. In this case, switching between preheating ( Figure 5 ) and regular control ( Figure 4 ).

Claims (16)

  1. A method for preheating an internal combustion engine injector including at least one valve to be activated by an electromagnet, in which the coil of the electromagnet is energized before the engine is started, characterized in that the coil of the electromagnet (21) is periodically powered with a preheating voltage (42), and that the profile of the current (33) within the coil is monitored and subjected to an evaluation to detect local current minima (43) and/or maxima (44) caused by armature reactions.
  2. A method according to claim 1, characterized in that the coil of the electromagnet (21) is periodically alternately powered with a preheating voltage (42) and short-circuited.
  3. A method according to claim 1 or 2, characterized in that the preheating voltage (42) is selected such that the valve closing member is moved before the current (33) in the coil reaches a saturation level (45).
  4. A method according to claim 1, 2 or 3, characterized in that the preheating voltage is selected such that the valve closing member reaches its maximum lift before the current in the coil reaches a saturation level.
  5. A method according to any one of claims 1 to 4, characterized in that the time interval (46) between the powering of the coil with the preheating voltage (42) and the occurrence of a current minimum (43) caused by the armature reaction is measured, and the periodic powering of the coil is terminated as soon as the measured time interval (46) has dropped below a defined setpoint.
  6. A method according to any one of claims 1 to 5, characterized in that the time interval (47) between the short-circuit of the coil and the occurrence of a current maximum (44) caused by the armature reaction is measured, and the periodic powering of the coil is terminated as soon as the measured time interval has dropped below a defined setpoint.
  7. A method according to any one of claims 1 to 6, characterized in that the temperature of the coil is monitored and the time intervals (30) between the energization periods are controlled as a function of the temperature.
  8. A method according to any one of claims 1 to 7, characterized in that the temperature is calculated from the resistance of the coil.
  9. A device for preheating an internal combustion engine injector (1) including at least one valve (3) to be activated by an electromagnet (21), in particular for carrying out the method according to any one of claims 1 to 8, including a control device for energizing the coil of the electromagnet (21), characterized in that the control device is configured for the periodic energization of the coil of the electromagnet (21) with a preheating voltage (42) and an evaluation device is provided, in which the profile of the current (33) within the coil is monitored and subjected to an evaluation for the detection of local current minima (43) and/or maxima (44) caused by armature reactions.
  10. A device according to claim 9, characterized in that the control device is configured such that the coil of the electromagnet (21) periodically is alternately powered with a preheating voltage (42) and short-circuited.
  11. A device according to claim 9 or 10, characterized in that the preheating voltage (42) is selected such that the valve closing member is moved before the current (33) in the coil reaches a saturation level (45).
  12. A device according to claim 9, 10 or 11, characterized in that the preheating voltage (42) is selected such that the valve closing member reaches its maximum stroke before the current (30) in the coil reaches a saturation level (45).
  13. A device according to any one of claims 9 to 12, characterized in that the evaluation circuit is configured to measure the time interval (46) between the powering of the coil with the preheating voltage (42) and the occurrence of a current minimum (43) caused by the armature reaction, wherein the periodic powering of the coil is terminated as soon as the measured time interval (46) has dropped below a defined setpoint.
  14. A device according to any one of claims 9 to 13, characterized in that the evaluation circuit is configured to measure the time interval (47) between the short-circuit of the coil and the occurrence of a current maximum (44) caused by the armature reaction, wherein the periodic powering of the coil is terminated as soon as the measured time interval (47) has dropped below a defined setpoint.
  15. A device according to any one of claims 9 to 14, characterized in that the control device comprises means for detecting the temperature of the coil, and the time intervals (30) between the energization periods are controlled as a function of the temperature.
  16. A device according to any one of claims 9 to 15, characterized in that the means for detecting the temperature comprise a resistance measuring means, wherein the temperature is calculated from the resistance of the coil.
EP20070701330 2006-04-03 2007-02-16 Method of preheating injectors of internal combustion engines Active EP2002110B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
AT0056906A AT502683B1 (en) 2006-04-03 2006-04-03 Fuel injector preheating method for internal combustion engine, involves monitoring and evaluating current characteristic in coil of electromagnet to detect local current minima and/or current maxima caused by armature reactions
PCT/AT2007/000086 WO2007112462A1 (en) 2006-04-03 2007-02-16 Method of preheating injectors of internal combustion engines

Publications (2)

Publication Number Publication Date
EP2002110A1 EP2002110A1 (en) 2008-12-17
EP2002110B1 true EP2002110B1 (en) 2009-10-28

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US (1) US8096485B2 (en)
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JP (1) JP4834145B2 (en)
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US20090145491A1 (en) 2009-06-11
WO2007112462A1 (en) 2007-10-11
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DE502007001859D1 (en) 2009-12-10
JP4834145B2 (en) 2011-12-14
KR20080106588A (en) 2008-12-08
EP2002110A1 (en) 2008-12-17
ATE447103T1 (en) 2009-11-15
CN101421506B (en) 2011-12-14
AT502683B1 (en) 2007-05-15
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AT502683A4 (en) 2007-05-15
CN101421506A (en) 2009-04-29

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