EP1248904A1 - Fuel injecting device for internal combustion engine - Google Patents

Fuel injecting device for internal combustion engine

Info

Publication number
EP1248904A1
EP1248904A1 EP00981424A EP00981424A EP1248904A1 EP 1248904 A1 EP1248904 A1 EP 1248904A1 EP 00981424 A EP00981424 A EP 00981424A EP 00981424 A EP00981424 A EP 00981424A EP 1248904 A1 EP1248904 A1 EP 1248904A1
Authority
EP
European Patent Office
Prior art keywords
nozzle
injection device
fuel
injector
fuel injection
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
EP00981424A
Other languages
German (de)
French (fr)
Other versions
EP1248904B1 (en
Inventor
André AGNERAY
Laurent Levin
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.)
Renault SAS
Original Assignee
Renault SAS
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 Renault SAS filed Critical Renault SAS
Publication of EP1248904A1 publication Critical patent/EP1248904A1/en
Application granted granted Critical
Publication of EP1248904B1 publication Critical patent/EP1248904B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • 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
    • F02M69/00—Low-pressure fuel-injection apparatus ; Apparatus with both continuous and intermittent injection; Apparatus injecting different types of fuel
    • F02M69/04—Injectors peculiar thereto
    • F02M69/041—Injectors peculiar thereto having vibrating means for atomizing the fuel, e.g. with sonic or ultrasonic vibrations
    • 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
    • F02M51/0603—Injectors peculiar thereto with means directly operating the valve needle using piezoelectric or magnetostrictive 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
    • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
    • F02M2200/30—Fuel-injection apparatus having mechanical parts, the movement of which is damped
    • F02M2200/306—Fuel-injection apparatus having mechanical parts, the movement of which is damped using mechanical means

Definitions

  • the present invention relates to a fuel injection device for an internal combustion engine intended in particular to equip a motor vehicle.
  • the invention relates more particularly to a fuel injection device making it possible to atomize the fuel injected in the form of very fine droplets.
  • the fuel injection devices used today on internal combustion engines fitted to motor or road vehicles conventionally operate on the model of a valve, the open or closed state of which is continuously controlled, the dosage of the injected fuel then done directly by the opening time.
  • Such injection systems include an electric fuel supply pump which supplies, via a distribution manifold, all of the injectors under a pressure having a constant difference with the pressure prevailing in the intake manifold. through a pressure regulator.
  • an electric fuel supply pump which supplies, via a distribution manifold, all of the injectors under a pressure having a constant difference with the pressure prevailing in the intake manifold. through a pressure regulator.
  • electromagnet actuating the valve of each injector one controls the beginning and the duration of opening of this one and one then determines a precise flow of fuel for each one of the injectors, thus the quantity of fuel injected depends only on the opening time of the electro-injectors.
  • the injectors of the electromagnetically controlled needle type which are the most commonly used, however have limits which hinder the improvement of engine performance, in particular in terms of pollution control.
  • the times taken to open or close the needles are still too high, around 1 to 2 ms, which prevents the injection from being distributed correctly over the entire opening time of the valve.
  • the minimum opening time which determines the minimum dose of fuel that can be injected, is still too long for certain engine operating points.
  • Known needle injectors also have injection holes of relatively large diameters to allow the delivery of the required quantities of fuel for operations at full load and high engine speeds. This arrangement generates fuel jets having drops of large dimensions, which slows down the vaporization of the fuel (and therefore the preparation of the fuel mixture) and is capable of promoting the phenomenon of wall wetting.
  • the non-vaporized fuel tends to settle on the walls of the intake duct or the combustion chamber (by direct injection).
  • Such a deposit causes metering problems, particularly acute in the transients due to a lack of knowledge of the quantity of fuel which actually enters the combustion chamber. corresponding.
  • This wall wetting phenomenon is one of the major causes of the high pollutant emissions during cold engine starts.
  • This device is of the type comprising an injector connected to a fuel supply circuit under a suitable pressure, this injector comprising an injection nozzle at the end of which is formed at least one fuel injection orifice and this injector cooperating with means of cyclic vibration controlled by the electronic engine control system so as to cause mechanical oscillations in bending of the injection nozzle, this nozzle injection being adapted to eject a predetermined quantity of fuel at each of its oscillations.
  • the object of the present invention is to improve this new type of injection device by proposing a new architecture of injector body which is simpler to produce, in particular in that it is no longer necessary to have a nozzle for injection formed by a plurality of channels of suitable dimensions, joined in a bundle.
  • the fuel injection device for internal combustion engine comprises an injector connected to a fuel circuit under a suitable pressure.
  • the fuel injection device for an internal combustion engine is characterized in that the injector comprises a cylindrical nozzle supplied with fuel and at the end of which is formed an injection orifice, means for cyclic vibration of the nozzle such as a transducer, said cyclic vibration means being controlled in duration and intensity by the electronic engine control system, and shutter means biased by elastic return means against the end of the nozzle, the elastic elastic return means being formed by a rod passing through the body of the injector to a cavity situated at the opposite end with respect to the injection orifice, the rod cooperating with a mass and damping means housed in the cavity, the vibration of the nozzle and shutter means ensuring the ejection of a predetermined amount of fuel.
  • the injector comprises a cylindrical nozzle supplied with fuel and at the end of which is formed an injection orifice, means for cyclic vibration of the nozzle such as a transducer, said cyclic vibration means being controlled in duration and intensity by the electronic engine control system, and shutter means biased by elastic return means against the end of the nozzle, the
  • the shutter means are integral with the rod, the flared end of which forms a valve, the rod being mounted axially movable inside said nozzle and being secured by the intermediate damping means with the nozzle.
  • the damping means are formed by one of an elastic washer.
  • the cavity is formed after the part of the transducer extending behind the injector.
  • the transducer comprises a stack of more than two active components.
  • the injector can be fixed to the cylinder head by pressing on a seal at the junction where the displacements are minimum.
  • the active components of the transducer are formed from a piezoelectric material.
  • the active components of the transducer are formed from a magnetostrictive material.
  • FIG. 1 represents an overall view, in axial section, of the injection device according to the invention
  • FIGS. 2 to 5 schematically explain the operating principle of the injection device according to the invention
  • Figure 6 is a partial sectional view of an internal combustion engine cylinder head equipped with a fuel injection device 1 according to the invention.
  • FIG. 7 is a view in axial section detailing the distribution of amplitude of vibration along the axis of the injector shown in FIG. 1.
  • FIG. 8 is a schematic view of the control circuit of the transducer shown in FIG. 1.
  • FIG. 1 the body of the injector object of the present invention has been detailed.
  • the body of the inj ector essentially comprises two separate bodies which cooperate with each other.
  • the first member is composed of means capable of generating vibrations in a longitudinal mode at ultrasonic frequencies such as a transducer 1, which transducer ends in the lower part by a nozzle of cylindrical shape 3 in which the vibrations coming from the transducer 1.
  • the whole of the transducer 1 has an internal cavity 15 intended to be filled with fuel under pressure by means of an axial bore 14 for supplying the fuel coming to connect to a circuit for supplying pressurized fluid 16.
  • the cavity 15 opens at the lower end 6 of the nozzle 3 through an injection orifice 5.
  • the second member is constituted by a cylindrical rod 4 housed axially movable inside the nozzle 3 and whose frustoconical lower end 7 extends outside the nozzle 3.
  • This end 7 forming a valve is adapted to come into contact with the inner surface of the nozzle 3 delimiting the lower opening 5 of the nozzle 3, surface defining a seat for said valve, and thus for closing the fuel injection orifice.
  • the other end of the rod 4 is provided with a mass 8 and connected elastically by a washer 9 to the body of the transducer 1. All of the mass 8 and the washer 9 are housed in a cavity 10 formed in the part rear of the transducer 1.
  • the mass 8 thus integrated into the injector can have a suitable volume by adjusting the height of this mass without modifying its radius or the geometry of the transducer part 1, which makes it possible to maintain a given radius for the entire inj ector.
  • This washer 9 exerts an elastic restoring force tending to apply the end 7 of the rod 4 against the surface surrounding the injection orifice 5 of the nozzle 3.
  • the value of the mass 8 and the rigidity of the washer 9 are chosen to form a system having a very long response time in relation to the durations of excitation of the transducer 1.
  • the transducer 1 is dimensioned to transmit a maximum of stresses at the junction 12 with the nozzle 3, this maximum of stresses corresponding to a minimum amplitude of vibration for the material.
  • the transducer 1 comprises a zone 17 consisting of a stack of active piezoelectric or magnetostrictive components, which, respectively under the application of an electric or magnetic field, deform in thickness.
  • This part 17 is sandwiched between two other elements 18 and 19 made up of elastic material.
  • prestressing means such as a screw 20.
  • the stack of several active components 17 makes it possible to add the thickness deformations generated by each of the rings, the resulting deformation of the total displacement of the stack of rings remaining below the elastic deformation limit of the prestressing means 20.
  • the increase in the number of rings in the stack generates a gain in displacement which makes it possible to compensate for the losses of amplification in part 19 of the transducer 1 when the diameter of this part 19 is reduced and there is a single transition zone 12 where the amplification takes place.
  • the engine control computer 31 sends two pulses corresponding to the start and end of the injection, during this time an ultrasonic frequency generator 32 sends a wave train (level 5V) at a frequency given at the input of an amplifier 33, which makes it possible to attack the piezoelectric ceramics in alternating voltage
  • the assembly composed of the transducer 1 and the nozzle 3 is dimensioned to resonate at the excitation frequency of the active components 17 and to amplify the longitudinal displacements up to the level of the lower end of the nozzle 3.
  • the rod 4 initially closing the opening 5 by its end 7 forming a valve, deforms under the impulse which is provided to it when the nozzle 3 starts to oscillate. This deformation is distributed elastically over the entire length of the rod 4 and is reflected at the interface between the rod 4 and the mass 8.
  • FIG. 2 describes the relative variation in position between the end 7 of the rod 4 (points Ai) and the end 6 of the nozzle 3 (points Bi) for 3 cycles of oscillation of the resonator assembly.
  • Figure 3 illustrates the positions of points Ai and Bi as a function of time.
  • the opening of the annular slot 21 is therefore oscillating with a maximum amplitude equal to the maximum difference in amplitude of vibration between the valve 7 and the end 6 as shown in Figure 4.
  • the opening frequency of the slot then depends on the excitation frequency chosen for the transducer 1 and the natural frequencies of the rod 4.
  • the minimum opening time of the injection device is of the same order as the excitation period applied to the transducer 1, which excitation can take place at a few tens of kilohertz, typically 50 kHz, which allows minimum opening times. of the order of 20 ⁇ s. This makes it possible to deliver micro-quantities of liquid during a reduced period of time compared with more conventional injection devices where the minimum time to operate the opening and closing of the injection nose is rather 300 ⁇ s.
  • FIG. 6 there is shown a mode of implantation of an injector according to the invention in an internal combustion engine of a motor vehicle.
  • the fuel supply to the engine is of the electronically controlled multipoint type through which each combustion chamber 25 is supplied directly into fuel by at least one fuel injector 1 opening into the chamber.
  • the body of the injector is fixed to the cylinder head 24 of the engine at its upper end by means which are not shown, this upper end being moreover connected to a fuel supply pipe.
  • the diameter of the nozzle 3 is dimensioned to touch the wall of the well 28 with a spacing corresponding to the thickness of the thermal layer so as to avoid the accumulation of heat towards the end of the nozzle 3.
  • the transducer 1 comprises a steel cylinder 18 of diameter 20 mm and height 35 mm comprising in its upper part a housing 10 of height 15 mm for placing the mass 8 and comprising in its lower part a threaded pin 20.
  • the threaded axis of the cylinder 18 makes it possible to prestress piezoelectric ceramic rings (external diameter 20 mm, internal diameter 6 mm, thickness 2 mm) between the cylinders 18 and the cylinder 19 having a thread 23.
  • the ceramics are arranged with anti-parallel polarizations, electrodes 13 being interposed between each pair of ceramics.
  • a titanium rod 4 with a diameter of 2 mm and comprising a conical end 7 with an external diameter of 5 mm is inserted in the axis of the transducer 1.
  • An elastic washer 9 has an orifice allowing the rod 4 to pass and is supported on the lower surface of the housing 10.
  • a cylindrical mass 8 comprising a thread is screwed onto the other end of the rod 4 comprising a thread.
  • the mass 8 is screwed until the desired preload is obtained, enabling the conical end 7 of the rod 4 to be applied to the zone 5 of the nozzle 3, the contact force then being maintained by the elasticity of the 'rod 4 and washer 9 assembly.
  • the pre-stress applied allows on the one hand the sealing of the opening 5 of the nozzle 3 when the fluid 16 is supplied with a given pressure and on the other hand the possible take-up of wear in the contact area of the valve 7 with the nozzle 3.
  • the value of the mass 8 and the rigidity of the washer 9 are chosen to form a system having a very long response time compared to the durations of excitation of the transducer of the order of 1 to 20 miliseconds at most.
  • the material of which the cup is made can be based on polymers having a very high rate of attenuation of elastic deformations in dynamics.
  • the mechanical structure is resonant with an oscillation amplitude profile depending on the position on the axis shown in Figure 7.
  • the inj ector can be maintained at the junction 12 which is a vibration node.
  • the nozzle 3 then transmits the vibrations to its end 6 which deforms with an oscillating movement, which end 6, in turn elastically deforms the rod 4.
  • the amplitude of oscillation for a voltage of 60 volts applied to each electrode is close to 20 microns, thus leaving an opening 21 generating a fluid film whose thickness is of the same order (20 microns).
  • This fluid film is fragmented by the closing of the opening 21 which occurs after a very short time (every 20 ⁇ s).
  • the device thus makes it possible to generate, as required, very fine droplets 22.
  • the modulation of the amplitude of the opening 21 makes it possible to modulate the size of the drops and thus the flow rate with response times of the order of 20 ⁇ s.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Fuel-Injection Apparatus (AREA)

Abstract

The invention concerns a fuel injection device for an internal combustion engine comprising an injector, characterised in that said injector is arranged in the injection orifice (5), means for causing the nozzle (3) to vibrate cyclically such as a transducer (1) controlled in duration and in intensity by the engine electronic control system, and closure means (7) returned by elastic return means against the end (6) of the nozzle (3), said elastic return means being formed by a rod (4) passing through the injector body up to a cavity (10) located at the opposite end relative to the injection orifice (5), said rod co-operating with a chassis ground (8) and damping means (9) housed in said cavity (10), the vibrating of the nozzle (3) and the closure means (7) ensuring the ejection of a predetermined amount of fuel.

Description

DISPOSITIF D'INJECTION DE CARBURANT POUR MOTEUR A COMBUSTION INTERNE FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINE
La présente invention se rapporte à un dispositif d'injection de carburant pour moteur à combustion interne destiné notamment à équiper un véhicule automobile. L'invention concerne plus particulièrement un dispositif d'injection de carburant permettant d'atomiser le carburant injecté sous forme de très fines gouttelettes.The present invention relates to a fuel injection device for an internal combustion engine intended in particular to equip a motor vehicle. The invention relates more particularly to a fuel injection device making it possible to atomize the fuel injected in the form of very fine droplets.
Les dispositifs d'injection de carburant utilisés aujourd'hui sur les moteurs à combustion interne équipant les véhicules automobiles ou routiers, fonctionnent classiquement sur le modèle d'une vanne dont on commande en permanence l'état ouvert ou fermé, le dosage du carburant injecté se faisant alors directement par le temps d'ouverture.The fuel injection devices used today on internal combustion engines fitted to motor or road vehicles, conventionally operate on the model of a valve, the open or closed state of which is continuously controlled, the dosage of the injected fuel then done directly by the opening time.
De tels systèmes d'injection comprennent une pompe électrique d'alimentation en carburant qui alimente, par le canal d'une rampe de distribution, l'ensemble des injecteurs sous une pression présentant une différence constante avec la pression régnant dans le collecteur d'admission grâce à un régulateur de pression. En contrôlant électroniquement l' électroaimant actionnant la soupape de chaque injecteur, on commande le début et la durée d' ouverture de celle-ci et on détermine alors un débit précis de carburant pour chacun des injecteurs, ainsi la quantité de carburant injectée dépend uniquement du temps d'ouverture des électro-injecteurs . Les injecteurs du type à aiguille commandée électromagnétiquement, qui sont les plus communément employés, présentent toutefois des limites qui freinent l'amélioration des performances des moteurs notamment en terme de dépollution. En particulier les temps mis pour ouvrir ou fermer les aiguilles sont encore trop élevés, d'environ 1 à 2 ms, ce qui empêche de répartir correctement l'injection sur tout le temps d'ouverture de la soupape. De plus, le temps minimum d'ouverture, qui détermine la dose minimale de carburant pouvant être injecté, est encore trop important pour certains points de fonctionnement moteur.Such injection systems include an electric fuel supply pump which supplies, via a distribution manifold, all of the injectors under a pressure having a constant difference with the pressure prevailing in the intake manifold. through a pressure regulator. By electronically controlling the electromagnet actuating the valve of each injector, one controls the beginning and the duration of opening of this one and one then determines a precise flow of fuel for each one of the injectors, thus the quantity of fuel injected depends only on the opening time of the electro-injectors. The injectors of the electromagnetically controlled needle type, which are the most commonly used, however have limits which hinder the improvement of engine performance, in particular in terms of pollution control. In particular, the times taken to open or close the needles are still too high, around 1 to 2 ms, which prevents the injection from being distributed correctly over the entire opening time of the valve. In addition, the minimum opening time, which determines the minimum dose of fuel that can be injected, is still too long for certain engine operating points.
Les injecteurs à aiguille connus présentent par ailleurs des orifices d'injection de diamètres relativement importants pour permettre de débiter les quantités requises de carburant pour les fonctionnements à pleine charge et hauts régimes des moteurs. Cette disposition génère des jets de carburant présentant des gouttes de fortes dimensions, ce qui freine la vaporisation du carburant (et donc la préparation du mélange carburé) et est à même de favoriser le phénomène de mouillage de paroi.Known needle injectors also have injection holes of relatively large diameters to allow the delivery of the required quantities of fuel for operations at full load and high engine speeds. This arrangement generates fuel jets having drops of large dimensions, which slows down the vaporization of the fuel (and therefore the preparation of the fuel mixture) and is capable of promoting the phenomenon of wall wetting.
En effet, le carburant non vaporisé tend à se déposer sur les parois du conduit d'admission ou de la chambre de combustion (en injection directe) . Un tel dépôt entraîne des problèmes de dosage, particulièrement aigus dans les transitoires par manque de connaissance de la quantité de carburant qui rentre effectivement dans la chambre de combustion correspondante. Ce phénomène de mouillage des parois est l'une des causes importantes des fortes émissions de polluants lors des démarrages à froid des moteurs.In fact, the non-vaporized fuel tends to settle on the walls of the intake duct or the combustion chamber (by direct injection). Such a deposit causes metering problems, particularly acute in the transients due to a lack of knowledge of the quantity of fuel which actually enters the combustion chamber. corresponding. This wall wetting phenomenon is one of the major causes of the high pollutant emissions during cold engine starts.
Par ailleurs, avec un injecteur classique à aiguille, à l'ouverture de l'aiguille lorsque cette dernière commence à quitter son siège, il se forme un bulbe de liquide qui disparaît lorsque l'aiguille est complètement levée, l'écoulement du fluide se régularisant alors. Ce changement dans la nature de l'écoulement rend impossible tout contrôle précis du débit instantané de l' injecteur.In addition, with a conventional needle injector, when the needle opens when the latter begins to leave its seat, a liquid bulb forms which disappears when the needle is fully raised, the fluid flow regularizing then. This change in the nature of the flow makes any precise control of the instantaneous injector flow impossible.
Certains ont cherché à résoudre ces différents problèmes, en développant des injecteurs utilisant des actuateurs piézo-électriques pour manoeuvrer l'aiguille de façon à abaisser la durée d'ouverture et de fermeture de l'aiguille, mais de tels systèmes qui fonctionnent toujours selon le principe d'une vanne, conservent des inconvénients importants liés notamment à la dispersion importante affectant la taille des gouttes dans le jet de carburant au sortir du nez de l' injecteur.Some have sought to solve these various problems, by developing injectors using piezoelectric actuators to maneuver the needle so as to reduce the duration of opening and closing of the needle, but such systems which always operate according to the principle of a valve, retain significant drawbacks related in particular to the significant dispersion affecting the size of the drops in the fuel jet leaving the nose of the injector.
L'ensemble des problèmes cités précédemment se solde donc par une vaporisation du carburant pouvant être incomplète et non homogène lors de la préparation du mélange carburé dans la chambre de combustion, des dosages imprécis, avec pour conséquence une combustion incomplète se traduisant par la formation d'une quantité élevée de gaz polluants et un déficit énergétique altérant le rendement du moteur. La Demanderesse a développé un nouveau type de dispositif d'injection de carburant permettant de résoudre l'ensemble de ces problèmes, le dispositif étant apte à délivrer un nuage de gouttes de carburant dont les tailles sont calibrées pour assurer un dosage précis et suffisamment petites pour assurer la vaporisation complète et homogène du carburant injecté.All of the problems mentioned above therefore result in a vaporization of the fuel which may be incomplete and non-homogeneous during the preparation of the fuel mixture in the combustion chamber, imprecise dosages, with the consequence of incomplete combustion resulting in the formation of '' a high quantity of polluting gases and an energy deficit affecting engine performance. The Applicant has developed a new type of fuel injection device which makes it possible to solve all of these problems, the device being capable of delivering a cloud of fuel drops whose sizes are calibrated to ensure precise dosing and are small enough to ensure complete and homogeneous spraying of the injected fuel.
Ce dispositif, décrit dans la demande de brevet n°FR97/05129, est du type comprenant un injecteur relié à un circuit d'alimentation en carburant sous une pression adaptée, cet injecteur comportant une buse d'injection à l'extrémité de laquelle est ménagé au moins un orifice d'injection de carburant et cet injecteur coopérant avec des moyens de mise en vibration cyclique pilotés par le système électronique de contrôle moteur de façon à provoquer des oscillations mécaniques en flexion de la buse d'injection, cette buse d'injection étant adaptée pour éjecter une quantité de carburant prédéterminée à chacune de ses oscillations.This device, described in patent application No. FR97 / 05129, is of the type comprising an injector connected to a fuel supply circuit under a suitable pressure, this injector comprising an injection nozzle at the end of which is formed at least one fuel injection orifice and this injector cooperating with means of cyclic vibration controlled by the electronic engine control system so as to cause mechanical oscillations in bending of the injection nozzle, this nozzle injection being adapted to eject a predetermined quantity of fuel at each of its oscillations.
La présente invention a pour objet de perfectionner ce nouveau type de dispositif d'injection en proposant une nouvelle architecture de corps d' injecteur plus simple à réaliser, en particulier en ce qu'il n'est plus nécessaire de disposer d'une buse d'injection formée par une pluralité de canaux de dimensions adaptées, réunis en faisceau.The object of the present invention is to improve this new type of injection device by proposing a new architecture of injector body which is simpler to produce, in particular in that it is no longer necessary to have a nozzle for injection formed by a plurality of channels of suitable dimensions, joined in a bundle.
Le dispositif d'injection de carburant pour moteur à combustion interne selon l'invention comprend un injecteur relié à un circuit de carburant sous une pression adaptée.The fuel injection device for internal combustion engine according to the invention comprises an injector connected to a fuel circuit under a suitable pressure.
Selon l'invention, le dispositif d'injection de carburant pour moteur à combustion interne est caractérisé en ce que l' injecteur comporte une buse cylindrique alimentée en carburant et à l'extrémité de laquelle est ménagé un orifice d'injection, des moyens de mise en vibration cyclique de la buse tel qu'un transducteur, lesdits moyens de mise en vibration cycliques étant pilotés en durée et en intensité par le système électronique de contrôle moteur, et des moyens obturateurs rappelés par des moyens élastiques de rappel contre l'extrémité de la buse, les moyens élastiques de rappel élastique étant formés par une tige traversant le corps de l' injecteur jusqu'à une cavité située à l'extrémité opposée par rapport à l'orifice d'injection, la tige coopérant avec une masse et des moyens d'amortissement logés dans la cavité, la mise en vibration de la buse et des moyens obturateurs assurant l'éjection d'une quantité de carburant prédéterminée .According to the invention, the fuel injection device for an internal combustion engine is characterized in that the injector comprises a cylindrical nozzle supplied with fuel and at the end of which is formed an injection orifice, means for cyclic vibration of the nozzle such as a transducer, said cyclic vibration means being controlled in duration and intensity by the electronic engine control system, and shutter means biased by elastic return means against the end of the nozzle, the elastic elastic return means being formed by a rod passing through the body of the injector to a cavity situated at the opposite end with respect to the injection orifice, the rod cooperating with a mass and damping means housed in the cavity, the vibration of the nozzle and shutter means ensuring the ejection of a predetermined amount of fuel.
Selon une autre caractéristique du dispositif d'injection objet de l'invention, les moyens obturateurs font corps avec la tige dont l'extrémité évasée forme clapet, la tige étant montée mobile axialement à l'intérieur de ladite buse et étant solidarisée par l'intermédiaire des moyens amortisseurs avec la buse. Selon une autre caractéristique du dispositif d'injection objet de l'invention, les moyens amortisseurs sont formés par une d'une rondelle élastique .According to another characteristic of the injection device which is the subject of the invention, the shutter means are integral with the rod, the flared end of which forms a valve, the rod being mounted axially movable inside said nozzle and being secured by the intermediate damping means with the nozzle. According to another characteristic of the injection device which is the subject of the invention, the damping means are formed by one of an elastic washer.
Selon une autre caractéristique du dispositif d'injection objet de l'invention, la cavité est formée après la partie du transducteur s ' étendant à l'arrière de 1 ' inj ecteur .According to another characteristic of the injection device which is the subject of the invention, the cavity is formed after the part of the transducer extending behind the injector.
Selon une autre caractéristique du dispositif d'injection objet de l'invention, le transducteur comporte un empilement de plus de deux composants actifs .According to another characteristic of the injection device which is the subject of the invention, the transducer comprises a stack of more than two active components.
Selon une autre caractéristique du dispositif d'injection objet de l'invention, l' inj ecteur peut être fixé à la culasse en appui sur un joint au niveau de la jonction où les déplacements sont minimum.According to another characteristic of the injection device which is the subject of the invention, the injector can be fixed to the cylinder head by pressing on a seal at the junction where the displacements are minimum.
Selon une autre caractéristique du dispositif d'injection objet de l'invention, les composants actifs du transducteur sont formés dans un matériau piézoélectrique .According to another characteristic of the injection device which is the subject of the invention, the active components of the transducer are formed from a piezoelectric material.
Selon une autre caractéristique du dispositif d'injection objet de l'invention, les composants actifs du transducteur sont formés dans un matériau magnétostrictif .According to another characteristic of the injection device which is the subject of the invention, the active components of the transducer are formed from a magnetostrictive material.
On comprendra mieux les buts, aspects et avantages de la présente invention, d'après la description donnée ci -après de différents modes de réalisation de l'invention, présentés à titre d'exemple non limitatifs, en se référant aux dessins annexés, dans lesquels:The objects, aspects and advantages of the present invention will be better understood from the description given below of different embodiments of the invention, presented by way of nonlimiting example, with reference to the appended drawings, in which:
la figure 1 représente une vue d'ensemble , en coupe axiale, du dispositif d'injection selon 1 ' invention;FIG. 1 represents an overall view, in axial section, of the injection device according to the invention;
les figures 2 à 5 explicitent schématiquement le principe de fonctionnement du dispositif d'injection selon l'invention;Figures 2 to 5 schematically explain the operating principle of the injection device according to the invention;
la figure 6 est une vue en coupe partielle d'une culasse de moteur à combustion interne équipée d'un dispositif d'injection de carburant selon 1 ' invention.Figure 6 is a partial sectional view of an internal combustion engine cylinder head equipped with a fuel injection device 1 according to the invention.
la figure 7 est une vue en coupe axiale détaillant la répartition d'amplitude de vibration le long de l'axe de l' inj ecteur représenté à la figure 1.FIG. 7 is a view in axial section detailing the distribution of amplitude of vibration along the axis of the injector shown in FIG. 1.
la figure 8 est une vue schématique du circuit de commande du transducteur représenté à la figure 1.FIG. 8 is a schematic view of the control circuit of the transducer shown in FIG. 1.
Conformément aux dessins annexés, seuls les éléments nécessaires à la compréhension de l'invention ont été représentés. De plus, pour faciliter la lecture de ces dessins, les mêmes pièces portent les mêmes références d'une figure à l'autre. En se reportant à la figure 1, on a détaillé le corps de l' inj ecteur objet de la présente invention.In accordance with the appended drawings, only the elements necessary for understanding the invention have been shown. In addition, to facilitate reading of these drawings, the same parts have the same references from one figure to another. Referring to FIG. 1, the body of the injector object of the present invention has been detailed.
Le corps de l' inj ecteur comporte essentiellement deux organes distincts coopérant les uns avec les autres .The body of the inj ector essentially comprises two separate bodies which cooperate with each other.
Le premier organe se compose de moyens aptes à générer des vibrations dans un mode longitudinal à des fréquences ultrasonores tel qu'un transducteur 1, lequel transducteur se termine dans la partie inférieure par une buse de forme cylindrique 3 dans laquelle sont amplifiées les vibrations provenant du transducteur 1.The first member is composed of means capable of generating vibrations in a longitudinal mode at ultrasonic frequencies such as a transducer 1, which transducer ends in the lower part by a nozzle of cylindrical shape 3 in which the vibrations coming from the transducer 1.
L'ensemble du transducteur 1 présente une cavité intérieure 15 destinée à être remplie de carburant sous pression par l'intermédiaire d'un perçage axial 14 d'amenée du carburant venant se connecter à un circuit d'alimentation de fluide sous pression 16. La cavité 15 débouche à l'extrémité inférieure 6 de la buse 3 par un orifice d'injection 5.The whole of the transducer 1 has an internal cavity 15 intended to be filled with fuel under pressure by means of an axial bore 14 for supplying the fuel coming to connect to a circuit for supplying pressurized fluid 16. The cavity 15 opens at the lower end 6 of the nozzle 3 through an injection orifice 5.
Le deuxième organe est constitué par une tige cylindrique 4 logée mobile axialement à l'intérieur de la buse 3 et dont l'extrémité inférieure de forme tronconique 7 s'étend à l'extérieur de la buse 3. Cette extrémité 7 formant clapet est adaptée pour venir en contact avec la surface intérieure de la buse 3 délimitant l'ouverture inférieure 5 de la buse 3, surface définissant un siège pour ledit clapet, et ainsi pour obturer l'orifice d'injection du carburant. L'autre extrémité de la tige 4 est munie d'une masse 8 et reliée élastiquement par une rondelle 9 au corps du transducteur 1. L'ensemble de la masse 8 et de la rondelle 9 sont logés dans une cavité 10 formée dans la partie arrière du transducteur 1. La masse 8 ainsi intégrée à l' inj ecteur peut avoir un volume adapté en ajustant la hauteur de cette masse sans modifier son rayon ni la géométrie de la partie transducteur 1, ce qui permet de conserver un rayon donné pour l'ensemble de l' inj ecteur. Cette rondelle 9 exerce une force de rappel élastique tendant à appliquer l'extrémité 7 de la tige 4 contre la surface entourant l'orifice d'injection 5 de la buse 3.The second member is constituted by a cylindrical rod 4 housed axially movable inside the nozzle 3 and whose frustoconical lower end 7 extends outside the nozzle 3. This end 7 forming a valve is adapted to come into contact with the inner surface of the nozzle 3 delimiting the lower opening 5 of the nozzle 3, surface defining a seat for said valve, and thus for closing the fuel injection orifice. The other end of the rod 4 is provided with a mass 8 and connected elastically by a washer 9 to the body of the transducer 1. All of the mass 8 and the washer 9 are housed in a cavity 10 formed in the part rear of the transducer 1. The mass 8 thus integrated into the injector can have a suitable volume by adjusting the height of this mass without modifying its radius or the geometry of the transducer part 1, which makes it possible to maintain a given radius for the the entire inj ector. This washer 9 exerts an elastic restoring force tending to apply the end 7 of the rod 4 against the surface surrounding the injection orifice 5 of the nozzle 3.
La valeur de la masse 8 et la rigidité de la rondelle 9 sont choisis pour former un système ayant un temps de réponse très grand par rapport aux durées d'excitation du transducteur 1.The value of the mass 8 and the rigidity of the washer 9 are chosen to form a system having a very long response time in relation to the durations of excitation of the transducer 1.
Le transducteur 1 est dimensionné pour transmettre un maximum de contraintes au niveau de la jonction 12 avec la buse 3, ce maximum de contraintes correspondant à un minimum d'amplitude de vibration pour le matériau.The transducer 1 is dimensioned to transmit a maximum of stresses at the junction 12 with the nozzle 3, this maximum of stresses corresponding to a minimum amplitude of vibration for the material.
Le transducteur 1 comporte une zone 17 constituée d'un empilement de composants actifs piézoélectriques ou magnétostrictifs, qui, respectivement sous l'application d'un champ électrique ou magnétique se déforment en épaisseur. Cette partie 17 est prise en sandwich entre deux autres éléments 18 et 19 constitués d'un matériau élastique. La liaison entre les éléments 17, 18 , et 19 est assurée par des moyens de précontrainte telle qu'une vis 20. L'empilement de plusieurs composants actifs 17 permet d'additionner les déformations en épaisseur générées par chacun des anneaux, la déformation résultante du déplacement total de l'empilement d'anneaux restant en dessous de la limite de déformation élastique du moyen de précontrainte 20. L'augmentation du nombre d'anneaux dans l'empilement génère un gain en déplacement qui permet de compenser les pertes d'amplification dans la partie 19 du transducteur 1 lorsque l'on réduit le diamètre de cette partie 19 et que l'on a une seule zone de transition 12 où s'opère l'amplification.The transducer 1 comprises a zone 17 consisting of a stack of active piezoelectric or magnetostrictive components, which, respectively under the application of an electric or magnetic field, deform in thickness. This part 17 is sandwiched between two other elements 18 and 19 made up of elastic material. The connection between the elements 17, 18, and 19 is ensured by prestressing means such as a screw 20. The stack of several active components 17 makes it possible to add the thickness deformations generated by each of the rings, the resulting deformation of the total displacement of the stack of rings remaining below the elastic deformation limit of the prestressing means 20. The increase in the number of rings in the stack generates a gain in displacement which makes it possible to compensate for the losses of amplification in part 19 of the transducer 1 when the diameter of this part 19 is reduced and there is a single transition zone 12 where the amplification takes place.
Comme indiqué à la figure 8, le calculateur de contrôle moteur 31 envoie deux impulsions correspondant au début et à la fin de l'injection, pendant cette durée un générateur de fréquence ultrasonore 32 envoie un train d'onde (niveau 5V) à une fréquence donnée en entrée d'un amplificateur 33, lequel permet d'attaquer les céramiques piézo-électriques en tension alternativeAs shown in Figure 8, the engine control computer 31 sends two pulses corresponding to the start and end of the injection, during this time an ultrasonic frequency generator 32 sends a wave train (level 5V) at a frequency given at the input of an amplifier 33, which makes it possible to attack the piezoelectric ceramics in alternating voltage
(de l'ordre de +-60V ) à la même fréquence ultrasonore pendant la durée d'injection.(around + -60V) at the same ultrasonic frequency during the injection period.
Sous l'application d'une tension électrique sur les électrodes des céramiques piézo-électriques, celles-ci se déforment et engendrent une contrainte élastique qui se transmet jusqu'à l'extrémité inférieure 6 de la buse 3. L'ensemble composé du transducteur 1 et de la buse 3 est dimensionné pour résonner à la fréquence d'excitation des composants actifs 17 et pour amplifier les déplacements longitudinaux jusqu'au niveau de l'extrémité inférieure de la buse 3.Under the application of an electrical voltage to the electrodes of piezoelectric ceramics, these deform and generate an elastic stress which is transmitted to the lower end 6 of the nozzle 3. The assembly composed of the transducer 1 and the nozzle 3 is dimensioned to resonate at the excitation frequency of the active components 17 and to amplify the longitudinal displacements up to the level of the lower end of the nozzle 3.
La tige 4, obturant initialement l'ouverture 5 par son extrémité 7 formant clapet, se déforme sous l'impulsion qui lui est fournie lorsque la buse 3 se met à osciller. Cette déformation se répartit élastiquement sur toute la longueur de la tige 4 et se réfléchit à l'interface entre la tige 4 et la masse 8.The rod 4, initially closing the opening 5 by its end 7 forming a valve, deforms under the impulse which is provided to it when the nozzle 3 starts to oscillate. This deformation is distributed elastically over the entire length of the rod 4 and is reflected at the interface between the rod 4 and the mass 8.
La réponse propre de la tige 4 d'une part et de la buse 3 d'autre part permettent de faire osciller l'extrémité 7 et l'ouverture 5 avec une variation de phase et d'amplitude. Cette variation se traduit par l'ouverture d'une fente annulaire 21 entre la tige 4 et l'extrémité 6 de la buse 3, la largeur de la fente dépendant de l'écart relatif entre l'amplitude d'oscillation de l'extrémité 6 de la buse 3 et l'amplitude d'oscillation du clapet 7.The proper response of the rod 4 on the one hand and of the nozzle 3 on the other hand allow the end 7 and the opening 5 to oscillate with a phase and amplitude variation. This variation results in the opening of an annular slot 21 between the rod 4 and the end 6 of the nozzle 3, the width of the slot depending on the relative difference between the amplitude of oscillation of the end 6 of the nozzle 3 and the amplitude of oscillation of the valve 7.
La figure 2 décrit la variation relative de position entre l'extrémité 7 de la tige 4 (points Ai) et l'extrémité 6 de la buse 3 (points Bi) pour 3 cycles d'oscillation de l'ensemble résonateur. La figure 3 illustre les positions des points Ai et Bi en fonction du temps .FIG. 2 describes the relative variation in position between the end 7 of the rod 4 (points Ai) and the end 6 of the nozzle 3 (points Bi) for 3 cycles of oscillation of the resonator assembly. Figure 3 illustrates the positions of points Ai and Bi as a function of time.
L'ouverture de la fente annulaire 21 est donc oscillante avec une amplitude maximale égale à la différence maximale d'amplitude de vibration entre le clapet 7 et l'extrémité 6 comme l'indique la figure 4. La fréquence d'ouverture de la fente dépend alors de la fréquence d'excitation choisie pour le transducteur 1 et des fréquences propres de la tige 4.The opening of the annular slot 21 is therefore oscillating with a maximum amplitude equal to the maximum difference in amplitude of vibration between the valve 7 and the end 6 as shown in Figure 4. The opening frequency of the slot then depends on the excitation frequency chosen for the transducer 1 and the natural frequencies of the rod 4.
Selon le cycle de fonctionnement indiqué figureDepending on the operating cycle shown in the figure
2, l'accostage de l'extrémité 7 de la tige 4 sur les bords de l'extrémité 6 de la buse 3 peut se produire avec une vitesse relative très faible, n'induisant pas de choc élastique de forte intensité.2, docking of the end 7 of the rod 4 on the edges of the end 6 of the nozzle 3 can occur with a very low relative speed, not inducing a high intensity elastic shock.
Le temps d'ouverture minimum du dispositif d'injection est du même ordre que la période d'excitation appliquée au transducteur 1, laquelle excitation peut se faire à quelques dizaines de kilohertz, typiquement 50 kHz, ce qui autorise des temps d'ouverture minimum de l'ordre de 20 μs . Ceci permet de délivrer des micro-quantités de liquide pendant un laps de temps réduit par rapport aux dispositifs d'injection plus classiques où le temps minimum pour opérer l'ouverture et la fermeture du nez d'injection est plutôt de 300 μs .The minimum opening time of the injection device is of the same order as the excitation period applied to the transducer 1, which excitation can take place at a few tens of kilohertz, typically 50 kHz, which allows minimum opening times. of the order of 20 μs. This makes it possible to deliver micro-quantities of liquid during a reduced period of time compared with more conventional injection devices where the minimum time to operate the opening and closing of the injection nose is rather 300 μs.
En se reportant à la figure 6, on a représenté un mode d'implantation d'un injecteur selon l'invention dans un moteur à combustion interne de véhicule automobile .Referring to Figure 6, there is shown a mode of implantation of an injector according to the invention in an internal combustion engine of a motor vehicle.
L'alimentation en carburant du moteur est du type multipoint à commande électronique par lequel chaque chambre de combustion 25 est alimentée directement en carburant par au moins un injecteur de carburant 1 débouchant dans la chambre.The fuel supply to the engine is of the electronically controlled multipoint type through which each combustion chamber 25 is supplied directly into fuel by at least one fuel injector 1 opening into the chamber.
Le corps de l' inj ecteur est fixé à la culasse 24 du moteur à son extrémité supérieure par des moyens non figurés, cette extrémité supérieure étant par ailleurs connectée à une conduite d'amenée du carburantThe body of the injector is fixed to the cylinder head 24 of the engine at its upper end by means which are not shown, this upper end being moreover connected to a fuel supply pipe.
16 également non figuré.16 also not shown.
L'étanchéité au droit du puits 28 de l' inj ecteur est assuré par un joint torique 26 maintenu en application entre la jonction 12 et la bordure 27 du puits d'injection 28.The tightness to the right of the well 28 of the injector is ensured by an O-ring 26 maintained in application between the junction 12 and the edge 27 of the injection well 28.
Le diamètre de la buse 3 est dimensionné pour effleurer la paroi du puits 28 avec un espacement correspondant à l'épaisseur de couche thermique de façon à éviter l'accumulation de chaleur vers l'extrémité de la buse 3.The diameter of the nozzle 3 is dimensioned to touch the wall of the well 28 with a spacing corresponding to the thickness of the thermal layer so as to avoid the accumulation of heat towards the end of the nozzle 3.
Selon un mode particulier de réalisation de l' inj ecteur objet de la présente invention, le transducteur 1 comprend un cylindre 18 en acier de diamètre 20 mm et hauteur 35 mm comportant dans sa partie supérieure un logement 10 de hauteur 15 mm pour placer la masse 8 et comportant dans sa partie inférieure un axe fileté 20.According to a particular embodiment of the injector object of the present invention, the transducer 1 comprises a steel cylinder 18 of diameter 20 mm and height 35 mm comprising in its upper part a housing 10 of height 15 mm for placing the mass 8 and comprising in its lower part a threaded pin 20.
L'axe fileté du cylindre 18 permet de précontraindre des anneaux de céramiques piézoélectriques (diamètre externe 20 mm, diamètre interne 6 mm, épaisseur 2 mm) entre le cylindres 18 et le cylindre 19 présentant un filetage 23. Les céramiques sont disposées avec des polarisations anti-parallèles, des électrodes 13 étant interposées entre chaque paire de céramique .The threaded axis of the cylinder 18 makes it possible to prestress piezoelectric ceramic rings (external diameter 20 mm, internal diameter 6 mm, thickness 2 mm) between the cylinders 18 and the cylinder 19 having a thread 23. The ceramics are arranged with anti-parallel polarizations, electrodes 13 being interposed between each pair of ceramics.
Une tige 4 en titane de diamètre 2 mm et comprenant une extrémité conique 7 de diamètre externe 5 mm est insérée dans l'axe du transducteur 1. Une rondelle élastique 9 comporte un orifice laissant passer la tige 4 et prend appui sur la surface inférieure du logement 10.A titanium rod 4 with a diameter of 2 mm and comprising a conical end 7 with an external diameter of 5 mm is inserted in the axis of the transducer 1. An elastic washer 9 has an orifice allowing the rod 4 to pass and is supported on the lower surface of the housing 10.
Une masse cylindrique 8 comportant un taraudage est vissée sur l'autre extrémité de la tige 4 comportant un filetage. Le vissage de la masse 8 se fait jusqu'à obtenir la précontrainte voulue permettant d'appliquer l'extrémité conique 7 de la tige 4 sur la zone 5 de la buse 3, la force de contact étant alors maintenue par l'élasticité de l'ensemble tige 4 et rondelle 9. La précontrainte appliquée permet d'une part l'étanchéité de l'ouverture 5 de la buse 3 lorsque le fluide 16 est alimenté avec une pression donnée et d'autre part le rattrapage d'usure éventuelle dans la zone de contact du clapet 7 avec la buse 3.A cylindrical mass 8 comprising a thread is screwed onto the other end of the rod 4 comprising a thread. The mass 8 is screwed until the desired preload is obtained, enabling the conical end 7 of the rod 4 to be applied to the zone 5 of the nozzle 3, the contact force then being maintained by the elasticity of the 'rod 4 and washer 9 assembly. The pre-stress applied allows on the one hand the sealing of the opening 5 of the nozzle 3 when the fluid 16 is supplied with a given pressure and on the other hand the possible take-up of wear in the contact area of the valve 7 with the nozzle 3.
La valeur de la masse 8 et la rigidité de la rondelle 9 sont choisis pour former un système ayant un temps de réponse très grand par rapport aux durées d'excitation du transducteur de l'ordre de 1 à 20 milisecondes au maximum. Le matériau dont est constitué la coupelle peut être à base de polymères ayant un très fort taux d'atténuation des déformations élastiques en dynamique.The value of the mass 8 and the rigidity of the washer 9 are chosen to form a system having a very long response time compared to the durations of excitation of the transducer of the order of 1 to 20 miliseconds at most. The material of which the cup is made can be based on polymers having a very high rate of attenuation of elastic deformations in dynamics.
Lorsque l'on applique une tension variable de l'ordre de 60 Volts aux bornes des céramiques par l'intermédiaire des électrodes communes 13, les céramiques se déforment en épaisseur et les déformations se transmettent dans l'ensemble de la structure .When a variable voltage of the order of 60 volts is applied to the terminals of the ceramics by means of the common electrodes 13, the ceramics deform in thickness and the deformations are transmitted throughout the structure.
Pour une fréquence d'excitation voisine de 50 kHz la structure mécanique est résonante avec un profil d'amplitude d'oscillation selon la position sur l'axe représenté à la figure 7. Le maintien de l' inj ecteur peut se faire au niveau de la jonction 12 qui est un nœud de vibration. La buse 3 transmet alors les vibrations jusqu'à son extrémité 6 qui se déforme avec un mouvement oscillant, laquelle extrémité 6, déforme à son tour élastiquement la tige 4.For an excitation frequency close to 50 kHz, the mechanical structure is resonant with an oscillation amplitude profile depending on the position on the axis shown in Figure 7. The inj ector can be maintained at the junction 12 which is a vibration node. The nozzle 3 then transmits the vibrations to its end 6 which deforms with an oscillating movement, which end 6, in turn elastically deforms the rod 4.
L'amplitude d'oscillation pour une tension de 60 Volts appliqués sur chaque électrode est voisine de 20 microns, laissant ainsi une ouverture 21 générant un film fluide dont l'épaisseur est du même ordre (20 microns) . Ce film fluide est fragmenté par la fermeture de l'ouverture 21 qui intervient au bout d'un temps très court ( toutes les 20μs) .The amplitude of oscillation for a voltage of 60 volts applied to each electrode is close to 20 microns, thus leaving an opening 21 generating a fluid film whose thickness is of the same order (20 microns). This fluid film is fragmented by the closing of the opening 21 which occurs after a very short time (every 20 μs).
Le dispositif permet ainsi de générer, selon les besoins, de très fines gouttelettes 22. La modulation de l'amplitude de l'ouverture 21 permet de moduler la taille des gouttes et ainsi le débit avec des temps de réponse de l'ordre de 20 μs .The device thus makes it possible to generate, as required, very fine droplets 22. The modulation of the amplitude of the opening 21 makes it possible to modulate the size of the drops and thus the flow rate with response times of the order of 20 μs.
Bien entendu, l'invention n'est nullement limité aux modes de réalisation décrits et illustrés qui n'ont été donnés qu'à titre d'exemple.Of course, the invention is in no way limited to the embodiments described and illustrated which have been given only by way of example.
Au contraire, l'invention comprend tous les équivalents techniques des moyens décrits ainsi que leurs combinaisons si celles-ci sont effectuées selon son esprit. On the contrary, the invention includes all the technical equivalents of the means described as well as their combinations if these are carried out according to the spirit.

Claims

REVENDICATIONS
[1] Dispositif d'injection de carburant pour moteur à combustion interne comprenant un injecteur relié à un circuit de carburant (16) sous une pression adaptée, caractérisé en ce que ledit injecteur comporte une buse (3) cylindrique alimentée en carburant et à l'extrémité de laquelle est ménagé un orifice d'injection (5), des moyens de mise en vibration cyclique de la buse (3) tel qu'un transducteur (1), lesdits moyens de mise en vibration cycliques étant pilotés en durée et en intensité par le système électronique de contrôle moteur, et des moyens obturateurs (7) rappelés par des moyens élastiques de rappel contre l'extrémité (6) de la buse (3), lesdits moyens élastiques de rappel élastique étant formés par une tige (4) traversant le corps de l' inj ecteur jusqu'à une cavité (10) située à l'extrémité opposée par rapport à l'orifice d'injection[1] Fuel injection device for internal combustion engine comprising an injector connected to a fuel circuit (16) under a suitable pressure, characterized in that said injector comprises a cylindrical nozzle (3) supplied with fuel and to the end of which is formed an injection orifice (5), means for cyclically vibrating the nozzle (3) such as a transducer (1), said cyclic vibrating means being controlled in duration and intensity by the electronic engine control system, and shutter means (7) biased by elastic return means against the end (6) of the nozzle (3), said elastic elastic return means being formed by a rod (4 ) passing through the body of the injector to a cavity (10) situated at the opposite end with respect to the injection orifice
(5) , ladite tige coopérant avec une masse (8) et des moyens d'amortissement (9) logés dans ladite cavité(5), said rod cooperating with a mass (8) and damping means (9) housed in said cavity
(10) , la mise en vibration de la buse (3) et des moyens obturateurs (7) assurant l'éjection d'une quantité de carburant prédéterminée .(10), the vibration of the nozzle (3) and shutter means (7) ensuring the ejection of a predetermined amount of fuel.
[2] Dispositif d'injection de carburant selon la revendication 1, caractérisé en ce que lesdits moyens obturateurs font corps avec ladite tige (4) dont l'extrémité évasée (7) forme clapet, ladite tige (4) étant montée mobile axialement à l'intérieur de ladite buse (3) et étant solidarisée par l'intermédiaire desdits moyens amortisseurs avec ladite buse (3) . [3] Dispositif d'injection de carburant selon l'une quelconque des revendications 1 a 2, caractérise en ce que lesdits moyens amortisseurs sont formes par une rondelle élastique (9) .[2] Fuel injection device according to claim 1, characterized in that said shutter means are integral with said rod (4) whose flared end (7) forms a valve, said rod (4) being mounted axially movable at the interior of said nozzle (3) and being secured by means of said damping means with said nozzle (3). [3] Fuel injection device according to any one of claims 1 to 2, characterized in that said damping means are formed by an elastic washer (9).
[4] Dispositif d' injection de carburant selon l'une quelconque des revendication 1 à 3, caractérisé en ce que ladite cavité (10) est formée après la partie (18) du transducteur (1) s 'étendant à l'arrière de l' injecteur.[4] Fuel injection device according to any one of claims 1 to 3, characterized in that said cavity (10) is formed after the part (18) of the transducer (1) extending to the rear of the injector.
[5] Dispositif d'injection de carburant selon l'une quelconque des revendication 1 à 4, caractérisé en ce que le transducteur (1) comporte un empilement de plus de deux composants actifs (17) .[5] Fuel injection device according to any one of claims 1 to 4, characterized in that the transducer (1) comprises a stack of more than two active components (17).
[6] Dispositif d'injection de carburant selon l'une quelconque des revendications précédentes, caractérisé en ce que l' injecteur peut être fixé à la culasse (24) en appui sur un joint (26) au niveau de la jonction[6] Fuel injection device according to any one of the preceding claims, characterized in that the injector can be fixed to the cylinder head (24) bearing on a seal (26) at the junction
(12) où les déplacements sont minimum.(12) where the displacements are minimum.
[7] Dispositif d' injection de carburant selon l'une quelconque des revendications précédentes, caractérisé en ce que les composants actifs (17) sont formés dans un matériau piézo-électrique .[7] Fuel injection device according to any one of the preceding claims, characterized in that the active components (17) are formed in a piezoelectric material.
[8] Dispositif d' injection de carburant selon l'une quelconque des revendications précédentes, caractérisé en ce que les composants actifs (17) sont formés dans un matériau magnétostrictif. [8] Fuel injection device according to any one of the preceding claims, characterized in that the active components (17) are formed in a magnetostrictive material.
EP00981424A 1999-11-19 2000-11-17 Fuel injecting device for internal combustion engine Expired - Lifetime EP1248904B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9914548 1999-11-19
FR9914548A FR2801346B1 (en) 1999-11-19 1999-11-19 FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINE
PCT/FR2000/003194 WO2001036813A1 (en) 1999-11-19 2000-11-17 Fuel injecting device for internal combustion engine

Publications (2)

Publication Number Publication Date
EP1248904A1 true EP1248904A1 (en) 2002-10-16
EP1248904B1 EP1248904B1 (en) 2006-01-11

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP00981424A Expired - Lifetime EP1248904B1 (en) 1999-11-19 2000-11-17 Fuel injecting device for internal combustion engine

Country Status (4)

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EP (1) EP1248904B1 (en)
DE (1) DE60025530T2 (en)
FR (1) FR2801346B1 (en)
WO (1) WO2001036813A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
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DE60025530D1 (en) 2006-04-06
EP1248904B1 (en) 2006-01-11
FR2801346A1 (en) 2001-05-25
DE60025530T2 (en) 2006-08-10
WO2001036813A1 (en) 2001-05-25
FR2801346B1 (en) 2002-10-31

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