EP0967388B1 - Dispositif d'injection amélioré pour moteurs diesel du type à rampe commune - Google Patents

Dispositif d'injection amélioré pour moteurs diesel du type à rampe commune Download PDF

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Publication number
EP0967388B1
EP0967388B1 EP99110390A EP99110390A EP0967388B1 EP 0967388 B1 EP0967388 B1 EP 0967388B1 EP 99110390 A EP99110390 A EP 99110390A EP 99110390 A EP99110390 A EP 99110390A EP 0967388 B1 EP0967388 B1 EP 0967388B1
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EP
European Patent Office
Prior art keywords
conduit
plunger
chamber
fuel
discharge
Prior art date
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EP99110390A
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German (de)
English (en)
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EP0967388A3 (fr
EP0967388A2 (fr
Inventor
Marino Sorgo
Marino Nobile
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Waertsilae Nsd Italia SpA
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WAERTSILAE ITALIA SpA
WAERTSILAE ITALIA SpA
Wartsila Italia SpA
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Publication of EP0967388A3 publication Critical patent/EP0967388A3/fr
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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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0003—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure
    • 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
    • F02M63/00—Other fuel-injection apparatus having pertinent characteristics not provided for in groups F02M39/00 - F02M57/00 or F02M67/00; Details, component parts, or accessories of fuel-injection apparatus, not provided for in, or of interest apart from, the apparatus of groups F02M39/00 - F02M61/00 or F02M67/00; Combination of fuel pump with other devices, e.g. lubricating oil pump
    • F02M63/0003—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure
    • F02M63/0007—Fuel-injection apparatus having a cyclically-operated valve for connecting a pressure source, e.g. constant pressure pump or accumulator, to an injection valve held closed mechanically, e.g. by springs, and automatically opened by fuel pressure using electrically actuated valves

Definitions

  • the present invention refers to a fuel injection device adapted to inject precise amounts of highly pressurized fuel into the cylinder of a two-stroke or four-stroke diesel engine.
  • the injection (phase and duration) control action is performed by the pump which must be appropriately synchronized with the engine.
  • the injector itself has on the contrary a passive role from a control point of view and, through the motion of the needle of the nozzle brought about by the pressure waves generated by the pump, ensures that the injection starts and ends at well-defined pressure levels.
  • a mechanically actuated and mechanically or electronically controlled pump pressurizes a manifold system, or common rail, with an action that is totally independent of the actual injection action which is on the contrary controlled by preferably electronically controlled injectors.
  • the injection control action, both in terms of timing thereof and duration or injected amount, is entirely performed by the injectors through the action of suitable electronically controlled valves that are an integral part of the injectors themselves.
  • the usual injection systems have an injection pressure that follows an almost triangular law versus time.
  • the initial and, above all, the final phase of the injection take therefore place at relatively low pressures and this causes the fuel to be atomized in a certainly not optimum manner in view of both the efficiency of the engine and the formation of polluting compounds.
  • the injection pump which, as already stated, is the actual regulation organ of these apparatuses, is driven by the engine and, therefore, its performance is strongly affected by the operating conditions, in particular the running speed thereof. The performance that can actually be obtained from the injection apparatus will therefore be strongly influenced by the rotating speed and the power output of the engine.
  • a one of the targets which engineers concerned with the development of injection systems are constantly aiming at is the possibility for the whole amount of fuel to be injected under optimum atomization conditions by implementing and performing injection cycles that are characterized by rapid pressure rises and falls in the initial and terminal parts of the cycle.
  • excessive values of these parameters tend to bring about negative effects, so that the need arises for the injection law that is actually capable of favouring the best possible combustion, in terms of both engine efficiency and formation of polluting compounds, to be found out for each engine and operating condition thereof.
  • the fuel injection systems for diesel engine of the so-called common-rail type are constituted by a pressure accumulator or manifold, which is kept at a constant pressure by means of a pump, and one or more injectors connected thereto through proper tubings.
  • a properly controlled organ which may be constituted by a valve or the same needle of the nozzle according to the various cases, regulates the fuel flow from said manifold to the nozzle and, therefore, the combustion chamber.
  • the operating principle of these injection apparatuses is very simple if compared with most currently used apparatuses. However, it is just this seeming simplicity where most of the practical implementation difficulties lie which have precluded any concrete development thereof until most recently.
  • the amount of fuel that is injected in each cycle depends exclusively on the response times of the control organs of the outflow coefficients of the flow governing organs (ie. valve, needle, nozzle), further to the rail pressure.
  • the control organs of the outflow coefficients of the flow governing organs ie. valve, needle, nozzle
  • the operating time and the hydraulic characteristics of the control organ determine both the phase, or timing, and the amount of fuel injected.
  • the characteristic parameters of the injection therefore, are not determined by the pump, as this on the contrary occurs in traditional apparatuses, but solely by the motion of the flow control organ. This of course makes injection fully independent of the manner in which the engine operates, owing to the regulation parameters being fully disengaged from both the rotation speed and the load of the engine.
  • the first one uses, as a control organ, the same needle of the nozzle and, therefore, fuel under pressure is constantly available upstream of the nozzle itself.
  • the needle is constantly unbalanced as far as hydraulic forces are concerned, so that remarkable forces are required in view of obtaining the desired response times.
  • the needle is therefore always operated by means of a system of pilot valves which are in turn actuated by an electric actuator.
  • the second category which the device being described here actually belongs to, makes use of a valve arranged between the rail and the nozzle, which is therefore only subject to the injection pressure during the active injection period, similarly to what actually occurs in traditional apparatuses with pump-connected control.
  • the motion of the needle of the nozzle is controlled by the course of the injection pressure in the same manner as it occurs in traditional apparatuses.
  • valves In this second case it is possible for valves to be provided which are balanced with respect to the mjection pressure and can be controlled directly by the electric actuator.
  • Those skilled in the art are generally well aware of the fact that the used of balanced valves offers considerable advantages not only from an operating point of view, but also in terms of performance, reliability and wide choice of valve types to ideally comply with any definite application requirements.
  • valves themselves can be either of the two-way or the three-way type.
  • the valve is constituted by a simple shutter, or plunger, which is adapted to shut and to open the passage from the rail to the nozzle; in the second case, which the present invention refers to, there is also a third port connecting the nozzle to a discharge circuit when the plunger is not activated.
  • the two-way plunger solution has a major drawback in that it brings about the pressure drop on the nozzle at the end of the injection solely by means of the flow on the same nozzle. The terminal phase of the injection turns therefore out to be inherently less rapid and stable with respect to the case in which the decompression of the volume between valve and nozzle occurs through the action of the plunger itself.
  • the pressure wave that causes the needle of the nozzle to open is generated by the motion of the valve much in advance of the moment in which the discharge port is fully closed. This contributes to the control of the injection being made precarious, in particular in the presence of short injection durations, ie. in the order of the response times of the actuator.
  • the disproportion between the outflow section of the valve and the one of the nozzle causes a considerable amount of fuel to be lost by leaking through the discharge seat during the motion of the valve, thereby lowering the overall efficiency of the injection apparatus owing to a non-negligible proportion of the pump flow rate being so discharged during these phases.
  • fuel will be used without distinction throughout the following description to mean each and any of the various liquid fuels suitable for the diesel cycle. Such a simplification will however by no means affect the clearness of what is being set forth therein, owing to the context in which such a term is used, as anyone skilled in the art is capable of readily understanding.
  • valve body 1 can be noticed to be provided with an inner housing in which there are arranged;
  • the actuator 2 that is adapted to actuate, in generally known manners, said plunger 4 so as to vary the position thereof within said valve body 1.
  • the upper portion of said inner housing is occupied by a typically annular chamber 11, while the central portion is occupied by said plunger 4.
  • the lower portion of said inner housing is in turn occupied by a chamber 12, which is also typically annular.
  • the outer walls of said plunger are closely adhering, albeit slidably, to the corresponding portion of the inner walls of said housing, so that no fuel is practically allowed to seep between said two chambers 11 and 12 through passageways or gaps that may be present between said plunger and the inner walls of said housing.
  • a discharge conduit 7 enters said chamber 11, while the injection conduit 6 leading to the needle valve or nozzle 51 is arranged to enter said chamber 12 along with the feeding conduit 5 from the high-pressure fuel source.
  • said injection 6 may be extended through the use of an extension conduit 61 before it reaches the nozzle 51.
  • the plunger 4 is adapted to move into two extreme positions; in the first one of these positions, ie. the resting one illustrated in Figure 4, the plunger is lowered and in such a position it is adapted to close the passage between the conduit 5 and the conduit 6, while the passage that is also known under the denomination of discharge valve, and whose section is generally indicated at A in the Figure, is open between said chamber 11 and a wall thereof that constitutes the seat 3, which will be defined further on as the seat 3 of the discharge valve, onto which the upper portion of the plunger comes to lie, thereby closing also the passage from the chamber 11 to the discharge conduit 7.
  • the devised solution is essentially based on a reduction of such a difference between said minimum sections.
  • the outflow section B of the injection conduit 6 can be made as small as considered appropriate, albeit within determined construction-related limits, and be situated in front of a conduit 10 of equivalent diameter provided inside said plunger.
  • Such a conduit 10 extends along a good portion of the body of said plunger to resurface therefrom into the chamber 11 comprised between said plunger and said seat 3 of the discharge valve.
  • the outflow port 5a between the conduit 5 and said chamber 12 and the inflow port 6a of the conduit 6 are arranged as close as possible to each other so that the two conduits are capable of being completely connected to each other even with a minimum stroke of the plunger. This reduces the connection times and the separation time of these conduits with respect to each other.
  • the minimum outflow sections at the inlet passage B and discharge passage A are determined by the inside diameters of the respective seats (D0 for the inlet seat, D2 for the discharge seat), the angle of the respective sealing cones, and the maximum lift of the plunger, which is obviously the same for both seats.
  • the condition of a balanced hydraulic load on said plunger requires on the contrary that the upward thrust surface be equal to the downward thrust surface.
  • This is obtained by making the outside sealing diameter of the inlet seat D 1 equal to the inside diameter of the discharge seat D2 and selecting the diameter D3 of the plunger in correspondence of the discharge seat in such a manner that the surface area of the circular crown comprised between D3 and D2 is equal to the surface area of the circle having the diameter D1.
  • the balance condition is therefore independent of the control diameter of the outflow section of the inlet seat D0, which can therefore be selected solely on the basis of fluid-dynamic considerations.
  • the possibility for the sealing angles of the two seats to be so differentiated offers the additional possibility for the respective outflow sections thereof to be made different.
  • the feeding conduit 5 When the plunger is in its resting position, the feeding conduit 5 is kept closed by the action of the contrasting spring or similar action of the actuator. In such a position, the nozzle is communicating with the discharge through the discharge port or passage A that is open, so that only the pressure of the discarge conduit 7 acts on the nozzle.
  • the actuator When the actuator is energized, it causes the plunger to move upwards, thereby opening the inlet port B and closing the discharge port A.
  • the plunger eventually reaches its end-of-stroke point, which is represented by the contact being established by the same plunger with the seat of the discharge port, the nozzle is fully connected with the feeding conduit, whereas the discharge conduit is fully closed.
  • the pressure rise that in this way is brought about upstream of the needle of the nozzle causes the latter to open, in a much similar manner in which this occurs in conventional injection devices.
  • the plunger When the actuator is then de-energized, the plunger, under the closing force generated by either the return spring or the actuator itself, moves back into its resting position, thereby opening the discharge port and closing the inlet one.
  • Such an opening of the discharge port brings about an abrupt pressure fall on the nozzle which in turn causes the needle to immediately close owing to the action of the return spring thereof, thereby reaching the aim of the present invention.
  • the invention is based on the marked dissymetry of the outflow sections of the two discharge and inlet ports A and B.
  • the outline inside the box 20 represents the development of the frustum of cone relating to the outflow section A and, in particular, the area of said section corresponds to the hatched zone; similarly, the drawing or outline inside the box 21 in Figure 5 represents the development of the frustum of cone relating to the outflow section of the inlet port B, while the area of such a section corresponds even in this case to the hatched zone.
  • connection of the two ports with each other can be brought about either inside the valve, as this is schematically illustrated in Figure 2, or along the plunger body.
  • the choice between such two solutions will be dictated only by the size of the plunger rod and the passage sections.
  • the valve body 1 of the discharge valve is floating with respect to the carrying structure of the valve and is kept on its guide by the plunger. This considerably facilitates the construction of the plunger-to-valve body 1 coupling and the seal of the discharge seat.
  • Figure 7 illustrates the technical solution that appears also in the preceding Figures
  • Figure 8 emphasizes how the connection between the conduit 6 and the chamber 11 can be carried out outside the plunger, namely through an appropriate fixed conduit 21A contained in the valve body 1.
  • Figure 9 on the contrary illustrates a further variant, in which the conduit 10 splits out, inside the plunger 4, into two symmetrical offshoots 10a and 10b that reach the chamber 11.
  • a further drawback which again depends on the type of coupling between frusto-conical surfaces, is ascribable to the weardown effect that takes place between the frusto-conical surface of the plunger 4 and the circular edge which, generally indicated at D2 in the Figure, delimitates the passage of the fuel from the chamber 11 to the discharge conduit 7.
  • a further drawback tends to occur under following condition: when the outflow section B is closed, the pressure at the inlet of the discharge conduit 7 tends to increase very swiftly, thereby bringing about, on the walls 20 of the plunger in Figure 5, a corresponding pressure increase that tends to throw out of balance the pressures that act on the same plunger altogether.
  • such an increase in the pressure on said walls 20 acts in the sense that it decreases the pressure with which the plunger closes onto the outflow section B and, as a result, it favours the occurrence of circumstances that may allow or cause the plunger to be raised, thereby opening said outflow section B.
  • said first chamber 11 in view of bestowing greater clearness to the description, is subdivided into two different contiguous and alternately connecting chambers, ie.:
  • said first chamber is provided with a portion 20 adapted to engage the upper portion 21 of said plunger in order to close said discharge conduit 7.
  • said portion 20 has a frusto-conical contour against which said upper portion 21 of the plunger is able to abut.
  • the upper portion 21 of said plunger has a frusto-conical contour that is coaxial with said frusto-conical portion 20 of said first chamber.
  • the angle X at the base of said frusto-conical portion 21 of said plunger is suitably smaller than the angle Y at the base of the frusto-conical contour of said portion 20 of said first chamber.
  • angle X might also be nil, as shown in Figure 11A, and in this case also the angle Y would be brought down to zero (zero divergence on a plane seal).
  • the line of abutment between the plunger and said first chamber becomes a circumference, of which the two intersecting points 45 and 46 with the section plane are indicated, and which is situated along the upper edge of the cylindrical body of the plunger.
  • a further advantage of the cone-cylinder type of seal lies in the fact that the seal diameter is not altered in the case of weardown effects. To state it more precisely, in the case of weardown or settling-down effects it is the contact between the two portions extending inwards that is modified within the chamber 11A, ie. where the pressure is the discharge one and not the injection one, so that the resulting effect on the overall balance condition is much lower. Furthermore, the closure of the passage towards said discharge conduit causes the flow of fuel through said conduit 10, which may or may not extend through the body of the plunger, to be interrupted.
  • the advantage as compared to the initial solution derives from the fact that the thrusts, or pushing effects, are due to the discharge pressure, and not the injection one, said two pressure being in a ratio of approx. two orders of magnitude.
  • the present invention teaches to make said plunger so that it actually comprises two coaxial cylindrical bodies 50, 51 firmly joined with each other, of which the first body 50 comprises the afore cited and illustrated frusto-conical portion 21 adapted to move into abutment against an outer wall of said first chamber, while the second body 51 has a diameter that is larger than the diameter of said first body, and is arranged in a position below said first body facing said second chamber 12.
  • Both said bodies and the housing are so sized and shaped as to enable said bodies to freely slide within said housing and, as far as said second body 51 is concerned, without any gap or side clearance.
  • the transition portion from said first body to said second body is formed by an annular step-like configuration 60 that may have any inclination whatsoever, ie. with an angle that may be situated anywhere between the theoretical extreme values from 0° to 180° with respect to the axis of the plunger, but preferably an inclination of 90°, consistently with the existing geometrical constraints.
  • said conduit 10 connects the side of said plunger which is in communication with said injection conduit 6, with the interior of said first chamber beyond said transition portion, as this is clearly illustrated in the Figure.
  • this is instrumental in enabling a pressure to act on said annular step-like configuration that tends to cause said plunger to lower and, therefore, to move into closing, wherein such a condition is still a preferred one in the case that the position of the plunger cannot be perfectly and effectively controlled with usual means.
  • the area of said annular step-like configuration, on a plane that is orthogonal to the moving direction of the plunger, must be sized appropriately and, therefore, also the mutual dimensions of said two bodies of the plunger are thereby determined.
  • the applicable sizing criteria are well within the ability of all those skilled in the art, so that they shall not be dealt with here.
  • conduit 10 can be provided outside the plunger, through an appropriate fixed conduit contained in said valve body 1 as shown in Figure 14.

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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)

Claims (15)

  1. Injecteur, de préférence du type électromagnétique, adapté pour alimenter du carburant vers un moteur à combustion interne, en particulier un moteur Diesel, comportant :
    une partie supérieure munie d'un actionneur (2) adapté pour être mis sous tension et hors tension de manière sélective,
    un corps de soupape (1) muni d'un boítier intérieur,
    un piston (4) actionné par ledit actionneur, et monté de manière coulissante dans ledit boítier dans lequel sont fournies, dans l'espace qui n'est pas occupé par ledit piston, au moins une première chambre (11) et une seconde chambre (12),
       une soupape à pointeau (51) adaptée pour commander l'écoulement de carburant sous pression, et capable de se déplacer vers une position ouverte pour permettre au carburant sous pression de passer à travers celle-ci lorsque ledit piston en va-et-vient, actionné par ledit actionneur, est dans la position définie par ledit actionneur qui est mis sous tension, et un position fermée pour interrompre l'écoulement du carburant sous pression lorsque ledit piston se déplace dans la position définie par l'actionneur mis hors tension,
    un premier conduit (5) adapté pour transférer un écoulement de carburant intermittent à partir d'une source de carburant haute pression vers une première desdites chambres,
    un deuxième conduit (7), qui est également défini comme conduit d'évacuation, adapté pour transférer un écoulement intermittent de carburant à partir d'une première desdites chambres vers des moyens d'évacuation de carburant,
    un troisième conduit (6) adapté pour transférer un écoulement intermittent de carburant à partir d'une première desdites chambres vers ladite soupape à pointeau, même par des conduits appropriés (61) agencés entre ladite première chambre et ladite vanne à aiguille,
    lesdits premier, deuxième et troisième conduits (5, 7, 6) étant capables d'être connectés de manière sélective et de manière alternée et/ou fermés selon la position prise par ledit piston (4), qui est adapté pour être actionné en prenant de manière sélective une première position correspondant à l'actionneur en rapport mis hors tension, de sorte que ledit premier conduit (5) et fermé, et une seconde position correspondant à l'actionneur en rapport mis sous tension, de sorte que ledit deuxième conduit (7) est fermé,
       caractérisé en ce que
    les parois extérieures dudit piston (4) sont entièrement en adhérence, bien que de manière coulissante, contre une partie des parois intérieures dudit boítier, de manière à empêcher du carburant quelconque de s'infiltrer ou de s'écouler entre lesdites deux chambres (11, 12) à travers des passages ou espaces agencés entre ledit piston et les parois intérieures dudit boítier,
    ledit conduit d'évacuation (7) s'écoule dans ladite première chambre (11),
    ledit premier conduit (5) et ledit troisième conduit (6) s'écoulent dans ladite seconde chambre (12),
    le tronçon d'écoulement de sortie (B) qui connecte, à l'intérieur de ladite seconde chambre (12), ledit premier conduit (5) audit troisième conduit (6) est du même ordre d'amplitude que le tronçon d'écoulement de sortie de ladite soupape à pointeau, et significativement plus petit que le tronçon d'écoulement de sortie (A) qui connecte, à l'intérieur de ladite première chambre (11), audit deuxième conduit ou conduit d'évacuation (7).
  2. Injecteur selon la revendication 1, caractérisé en ce que
    dans la position entièrement ouverte dudit piston, ledit troisième conduit (6) est établi en relation avec ledit premier conduit (5), tandis que ledit deuxième conduit (7) est entièrement fermé,
    dans la position extrême opposée dudit piston, ledit troisième conduit (6) est séparé dudit premier conduit (5), et est établi en relation avec ledit deuxième conduit ou conduit d'évacuation (7).
  3. Injecteur selon la revendication 2, caractérisé en ce que
    l'orifice d'écoulement de sortie (5a) dudit premier conduit (5) dans ladite seconde chambre (12) est sensiblement adjacent à l'orifice d'écoulement de sortie (6a) dudit troisième conduit,
    la partie finale de ladite seconde chambre (12) a la forme d'un tronc de cône, et la partie finale correspondante dudit piston a, en correspondance du tronçon d'écoulement de sortie dudit premier conduit (5), une forme tronconique adaptée pour être reliée de manière convenable à ladite partie finale de ladite seconde chambre (12), et pour fermer ledit tronçon d'écoulement de sortie (B),
    l'orifice d'écoulement de sortie (5a) dudit premier conduit est agencé sur une paroi de la partie tronconique finale de ladite seconde chambre (12),
    l'orifice d'entrée (6a) dudit troisième conduit est agencé sur le fond de ladite seconde chambre.
  4. Injecteur selon la revendication 3, caractérisé en ce que
    les sections d'écoulement de sortie minimum dans ledit passage d'entrée (B) et ledit passage d'évacuation (A) sont déterminées par les diamètres intérieurs des sièges respectifs (D0, D2), l'angle des cônes d'étanchéité respectifs et la levée maximum du piston,
    le diamètre d'étanchéité extérieur du siège intérieur (D1) est rendu égal au diamètre intérieur du siège d'évacuation (D2),
    le diamètre extérieur (D3) du piston en correspondance du siège d'évacuation est dimensionné de sorte que la surface de la couronne circulaire comprise entre ledit diamètre intérieur (D2) du siège d'évacuation et ledit diamètre extérieur (D3) du piston est égale à la surface du cercle dudit diamètre d'étanchéité extérieur (D1) du siège d'entrée.
  5. Injecteur selon la revendication 4, caractérisé en ce que ledit piston est muni d'au moins un canal intérieur longitudinal (10), et en ce qu'une ouverture (10c) dudit canal longitudinal est située en avant dudit orifice d'entrée (6a) dudit troisième conduit (6).
  6. Injecteur selon la revendication 5, caractérisé en ce que ledit canal intérieur (10) s'écoule, avec son tronçon supérieur, jusque dans ladite première chambre (11).
  7. Injecteur selon la revendication 6, caractérisé en ce qu'entre la partie supérieure dudit canal intérieur (10) et ladite première chambre (11) est agencé un conduit supplémentaire (31) qui a deux sorties distinctes dans ladite première chambre.
  8. Injecteur selon la revendication 7, caractérisé en ce que lesdites sorties distinctes sont opposées l'une par rapport à l'autre.
  9. Injecteur selon la revendication 4, caractérisé en ce qu'un conduit (21A) connectant ledit troisième conduit (6) à ladite première chambre (11) est agencé dans ledit corps de soupape (1).
  10. Injecteur selon la revendication 4, caractérisé en ce qu'entre la partie supérieure dudit canal intérieur (10) et ladite première chambre (11) sont agencés deux conduits distincts (10a, 10b).
  11. Injecteur selon l'une quelconque des revendications précédentes, dans lequel ladite première chambre (11) est subdivisée en deux chambres contiguës différentes et connectées de manière alternée, dont une chambre (11A), qui est également appelée la chambre de compensation, est formée par la partie dudit boítier qui est définie comme la partie creuse séparée communiquant en permanence avec le conduit d'évacuation (7) lorsque ledit piston est dans sa position de fermeture, la première chambre réelle (11) étant délimitée, vers ledit conduit d'évacuation (7), par ledit piston se fermant contre la partie correspondante dudit corps de soupape (1), caractérisé en ce que
    ladite première chambre réelle (11) est munie d'une paroi adaptée pour venir en contact avec une partie correspondante dudit piston afin de fermer ledit deuxième conduit ou conduit d'évacuation (7), ladite paroi ayant un contour tronconique avec un angle spécifique (X) à la base qui délimite la course dudit piston,
    ladite partie correspondante dudit piston a un contour tronconique, avec un angle spécifique (Y) à la base respective, coaxialement par rapport audit contour tronconique de ladite partie de ladite première chambre (11), où ledit angle à la base de ladite première chambre est supérieur à l'angle à la base de ladite partie tronconique de ladite partie correspondante dudit piston.
  12. Injecteur selon la revendication 11, caractérisé en ce que
    dans la position entièrement ouverte dudit piston, ledit troisième conduit (6) est établi en relation avec ledit premier conduit (5) tandis que ledit deuxième conduit (7) est entièrement fermé,
    ladite première chambre est fermée par rapport audit deuxième conduit (7) par la base cylindrique (45, 46) de ladite partie dudit piston venant en butée contre ledit contour tronconique de ladite partie (20) de ladite première chambre,
    dans la position extrême opposée dudit piston, ledit troisième conduit (6) est séparé dudit premier conduit (5), et est établi en relation avec ledit deuxième conduit ou conduit d'évacuation (7).
  13. Injecteur selon la revendication 11 ou 12, caractérisé en ce que ledit piston (4) est muni d'une partie supérieure (47) qui, sur son côté en vis-à-vis de ladite chambre de compensation (11A), a au moins un épaulement d'agrandissement (48) adapté pour intercepter la pression de ladite première chambre de manière à exercer une force sur ledit piston qui agit dans sa direction d'ouverture.
  14. Injecteur selon la revendication 1, caractérisé en ce que
    ledit piston (4) est muni de deux corps cylindriques et coaxiaux (50, 51), dont le premier corps (50) comporte une partie cylindrique et une partie tronconique (21) adaptée pour se déplacer en butée contre une paroi extérieure de ladite première chambre (11),
    le second corps (51) a un diamètre qui est plus grand que le diamètre dudit premier corps (50),
    ledit second corps peut coulisser librement dans ledit boítier, sans un espace ou jeu latéral quelconque,
    la partie de transition entre ledit premier corps et ledit second corps a la forme d'une configuration analogue à une marche annulaire (60),
    ladite configuration analogue à une marche annulaire a une inclinaison qui peut être située n'importe où entre les valeurs extrêmes théoriques allant de 0° à 180°, mais de préférence une inclinaison de 90°, par rapport à l'axe du piston,
    un conduit (10) connecte la partie d'extrémité inférieure dudit piston, qui communique avec ledit troisième conduit (6), avec l'intérieur de ladite première chambre (11), qui est délimitée sur un côté par ladite configuration analogue à une marche annulaire.
  15. Injecteur selon la revendication 14, caractérisé en ce que la surface de ladite configuration analogue à une marche annulaire (60), sur le plan qui est orthogonal à la direction de déplacement du piston, est dimensionnée de sorte que la pression induite par le carburant sur ladite configuration analogue à une marche annulaire est capable d'exercer une pression sur ledit piston qui, lorsque ce dernier est dans sa position ouverte, est telle qu'elle imprime au même piston une force qui a tendance à le déplacer dans sa position de fermeture en surmontant une autre pression hydraulique quelconque du carburant qui a tendance à le maintenir dans sa position ouverte.
EP99110390A 1998-06-22 1999-05-28 Dispositif d'injection amélioré pour moteurs diesel du type à rampe commune Expired - Lifetime EP0967388B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT1998PN000046A IT1305511B1 (it) 1998-06-22 1998-06-22 Dispositivo di iniezione perfezionato in motori dieseldenominati "common rail"
ITPN980046 1998-06-22

Publications (3)

Publication Number Publication Date
EP0967388A2 EP0967388A2 (fr) 1999-12-29
EP0967388A3 EP0967388A3 (fr) 2003-03-12
EP0967388B1 true EP0967388B1 (fr) 2005-01-19

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Application Number Title Priority Date Filing Date
EP99110390A Expired - Lifetime EP0967388B1 (fr) 1998-06-22 1999-05-28 Dispositif d'injection amélioré pour moteurs diesel du type à rampe commune

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EP (1) EP0967388B1 (fr)
AT (1) ATE287499T1 (fr)
DE (1) DE69923256T2 (fr)
IT (1) IT1305511B1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6895937B2 (en) 2002-07-01 2005-05-24 Mitsubishi Heavy Industries, Ltd. Fuel injector and diesel engine comprising the same
DE10241445A1 (de) * 2002-09-06 2004-03-18 Daimlerchrysler Ag 3/2-Wegeventil zur Steuerung einer Common-Rail-Einspritzdüse
IT1403006B1 (it) * 2010-12-06 2013-09-27 O M T Ohg Torino S P A Polverizzatore ad elevata vita operativa per iniettori meccanici ad alta pressione operanti con combustibile pesante

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5094215A (en) * 1990-10-03 1992-03-10 Cummins Engine Company, Inc. Solenoid controlled variable pressure injector
GB2295881A (en) * 1994-11-29 1996-06-12 Lucas Ind Plc Control valve
DE4445980C2 (de) * 1994-12-22 1999-12-30 Mtu Friedrichshafen Gmbh Einspritzsystem
GB9503341D0 (en) * 1995-02-21 1995-04-12 Lucas Ind Plc Valve

Also Published As

Publication number Publication date
ATE287499T1 (de) 2005-02-15
DE69923256D1 (de) 2005-02-24
EP0967388A3 (fr) 2003-03-12
IT1305511B1 (it) 2001-05-09
ITPN980046A1 (it) 1999-12-22
DE69923256T2 (de) 2005-06-23
EP0967388A2 (fr) 1999-12-29

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