EP0805266B1 - Internal combustion engine with pilot injection - Google Patents

Internal combustion engine with pilot injection Download PDF

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Publication number
EP0805266B1
EP0805266B1 EP19970400943 EP97400943A EP0805266B1 EP 0805266 B1 EP0805266 B1 EP 0805266B1 EP 19970400943 EP19970400943 EP 19970400943 EP 97400943 A EP97400943 A EP 97400943A EP 0805266 B1 EP0805266 B1 EP 0805266B1
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EP
European Patent Office
Prior art keywords
plug
combustion chamber
motor according
motor
yoke
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.)
Expired - Lifetime
Application number
EP19970400943
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German (de)
French (fr)
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EP0805266A1 (en
Inventor
Serge Bauraud
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.)
Automobiles Peugeot SA
Automobiles Citroen SA
Original Assignee
Automobiles Peugeot SA
Automobiles Citroen SA
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Publication date
Priority claimed from FR9605580A external-priority patent/FR2748295B1/en
Priority claimed from FR9606012A external-priority patent/FR2748777B1/en
Application filed by Automobiles Peugeot SA, Automobiles Citroen SA filed Critical Automobiles Peugeot SA
Publication of EP0805266A1 publication Critical patent/EP0805266A1/en
Application granted granted Critical
Publication of EP0805266B1 publication Critical patent/EP0805266B1/en
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B77/00—Component parts, details or accessories, not otherwise provided for
    • F02B77/08—Safety, indicating, or supervising devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the invention relates to an internal combustion engine, pilot fuel injection, directly into at least a combustion chamber provided with at least one orifice exhaust pipe closed cyclically by a valve.
  • the injection pump is in phase with the engine cycle. Fuel is injected into the chamber only a few degrees before top dead center (TDC). The fuel pressure reached is around 15 x 10 6 Pa.
  • the object of the present invention is to provide an engine for the type defined above, which can be fitted injectors controlled by solenoid valve without risk of deterioration caused by overpressure in the combustion chamber of each engine cylinder.
  • the engine according to the invention is characterized in that the combustion chamber is associated a protection device against overpressures in this room, able to put it in communication with an engine exhaust duct when the pressure in the combustion chamber exceeds a predetermined value.
  • the overpressure protection device includes a relief valve mounted in a channel formed in the engine cylinder head and capable of establishing the above communication between the combustion chamber and the exhaust duct.
  • the relief valve is formed by a member such as a ball kept closed on a seat under the effect a return means such as a spring.
  • the protective device channel communicates, in back of the relief valve, with the conduit exhaust, via a connecting channel.
  • the device protection includes means for fixing the candle arranged to yield under the action of a overpressure prevailing in the combustion chamber and allow the expulsion of the candle and the setting communication, through the free part of the well, of the combustion chamber with the exhaust duct of the engine.
  • the means of candle attachment include a sleeve through the candle and secured, for example by screwing, of the engine cylinder head, and a spring washer clamped between one end of the sleeve and one shoulder of the cylinder head and whose central part is supported on a shoulder of the spark plug so as to keep it pressed on its seat, the central part of the spring washer comprising areas breaking under shear under the action of the aforementioned overpressure.
  • the aforementioned sleeve comprises at its end opposite to the elastic washer an internal shoulder against which abuts the shoulder of the spark plug when the expulsion of it.
  • the candle includes an upper sleeve integral, for example by screwing, the cylinder head and a lower body connected to the sleeve by a frangible annular zone suitable for axially cross the latter by breaking this zone under the action of the above-mentioned overpressure.
  • the means fixing the candle are bayonet type where the candle body includes at least two pins engaging respectively in two retaining grooves lugs made in a cylindrical socket crossed by the candle and united, for example by the engine cylinder head to maintain the candle resting on its seat, the pins can be break the action of overpressure by shearing cited above.
  • the free part of the well is connected to the conduit exhaust through a cylinder head channel.
  • reference 1 designates a diesel type internal combustion engine cylinder head, pilot injectors (not shown), attached to cylinders, only one of which is shown in 2.
  • the reference 4 designates a combustion chamber delimited between the cylinder head 1 and a piston 3 and in which is directly injected fuel through the associated pilot injector.
  • the cylinder head is provided with a device 7 protection against overpressure in the room combustion 4.
  • This device essentially comprises a check valve. discharge 8 produced in the form of a ball mounted in a channel 9 which is practiced in the cylinder head and opens, at one end, in the combustion chamber 4 and, at its other end, outward.
  • the channel has two parts with circular cross-section, of diameters different. The part opening into the combustion 4 has a smaller diameter.
  • the junction of the two channel parts is configured from so as to form a seat 10 for the valve ball 8.
  • a coil spring 11 is provided in the channel portion larger diameter and pushes the valve ball on its seat by resting on a closure cap 12 of the canal.
  • the channel part located behind the valve, i.e. on the opposite side of the combustion chamber 4, communicates via transverse channels 14 with exhaust pipes 15, as shown on the FIG. 2, which open into the combustion chamber 4, in the usual way, each by a closable orifice 16 cyclically by a valve not shown here.
  • the Figure 3 shows the relative arrangement of channel 9 which houses the overload valve 8 and the two conduits exhaust 15 shown in Figure 2.
  • the ball 8 is maintained on its seat 10 under the action of the spring 11.
  • the ball 8 lifts from its seat at against the spring, which puts the combustion 4 in communication with the conduits exhaust 15, via channels 9 and 14. Thanks to this communication, the overpressure in room 4 is eliminated or even avoided.
  • the cylinder head 1 includes, for each of the combustion 4, a well 17 opening into chamber 4 and receiving a glow plug 18 which closes the well 17 when held in it for its use by fixing means.
  • the candle 18 a its central electrode 19 projecting into the chamber combustion 4 so as to heat the fuel during starting the engine.
  • the means for fixing the candle 18 include a sleeve 20 through which the spark plug 18 and integral with the cylinder head 1, for example in being screwed into a corresponding tapped hole 21 of the cylinder head 1 and coaxial with well 17.
  • These fixing means also include a spring washer 22 mounted between a lower end of the sleeve 20 and a shoulder 1a of cylinder head 1 so as to be tightened on the shoulder 1a by the sleeve 20.
  • FIG. 7 represents the elastic washer 22 in the free state and FIG.
  • this washer has its central part made up of a number of radial fins 22a, for example three in number, bearing, in the mounted position, on a shoulder 18a of the body of the candle 18 so as to keep it supported on its seat 1b of the cylinder head 1.
  • the fins 22a of the washer 22 are connected to the body of the latter by zones z 1 which can rupture by shearing as will now be described.
  • FIG. 4 shows in lower axial half-view the spark plug 18 in the position of use in the cylinder head and in upper axial half-view the spark plug 18 expelled.
  • the shoulder 18a of the body thereof comes to bear on an internal shoulder of the sleeve 20 opposite the washer 22 by means of a metal seal 23.
  • the overpressure in the chamber 4 is avoided or interrupted by evacuation of the gases from the combustion chamber towards the exhaust conduits C1 and C2 via channels 24 produced in the cylinder head 1.
  • the seal 23 also eliminates risks gas leakage during overpressure and also in normal operation while protecting the spark plug 18 against vibration.
  • Figures 9 and 10 show a third mode of realization allowing the expulsion of a candle preheating during an overpressure in the combustion 4.
  • the parts of Figures 9 and 10 common to those of FIGS. 4 and 5 bear the same references.
  • the candle 18 includes an upper sleeve 25 integral with the cylinder head 1, for example by screwing into a tapped hole corresponding 26 of the cylinder head 1 coaxial to the well 17 of reception of the candle 18, and a lower body 18b connected to the sleeve 25 by a frangible annular zone z2 and capable of crossing the latter axially by rupture of the frangible zone z2.
  • the annular zone z2 can be rupture during an overpressure prevailing in the combustion 4 so as to expel outwards the candle 18 as shown in FIG. 9 in axial half-view lower part of the spark plug 18.
  • the free part of the well 17 communicates, by through a channel 24 of the cylinder head 1, with at minus an exhaust system to evacuate gases overpressure of the combustion chamber 4.
  • the means for fixing the candle 18 in the well 17 of the cylinder head 1 are bayonet type, i.e. comprising at least two pins 27 secured to the body of the spark plug 18 and one cylindrical socket 28 through which the candle 18 passes being integral with the cylinder head 1, for example by screwing in a corresponding tapped hole 29 of cylinder head 1, the socket 28 comprising two grooves 28a, 28b shaped so as to allow axial engagement of the pins 27 in these and then by rotating the body of the candle 18, the engagement of the pins 28 in the parts curvilinear grooves 28a, 28b until they stop against the extreme walls thereof, thereby blocking the candle 18 relative to the cylinder head 1 to maintain the candle resting on its seat 1b.
  • bayonet type i.e. comprising at least two pins 27 secured to the body of the spark plug 18 and one cylindrical socket 28 through which the candle 18 passes being integral with the cylinder head 1, for example by screwing in a corresponding tapped hole 29 of cylinder head 1, the socket 28 comprising two grooves 28a,
  • the pins 28 can break by shearing under the action of a possible overpressure prevailing in the combustion chamber 4 so as to expel the candle 18 as shown in figure 11 on the axial half-view lower part of the spark plug 18.
  • the free part of the well 17 communicates with at minus an exhaust system through a channel 24 of the cylinder head 1 identical to that shown in FIG. 9.
  • the invention described above in the three modes of construction provides effective motor protection against deterioration caused by possible abnormal overpressure in at least one of the combustion of the engine by expelling the or each spark plug corresponding preheating and evacuating the gases from overpressure by a discharge channel.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Cylinder Crankcases Of Internal Combustion Engines (AREA)
  • Output Control And Ontrol Of Special Type Engine (AREA)

Description

L'invention concerne un moteur à combustion interne, à injection pilotée de carburant, directement dans au moins une chambre de combustion pourvue d'au moins un orifice de conduit d'échappement obturé cycliquement par une soupape.The invention relates to an internal combustion engine, pilot fuel injection, directly into at least a combustion chamber provided with at least one orifice exhaust pipe closed cyclically by a valve.

Dans les moteurs de ce type, qui sont connus, la pompe d'injection est en phase avec le cycle moteur. L'injection du carburant dans la chambre est effectuée quelques degrés seulement avant le point mort haut (PMH). La pression du combustible atteinte est de l'ordre de 15 x 106 Pa.In engines of this type, which are known, the injection pump is in phase with the engine cycle. Fuel is injected into the chamber only a few degrees before top dead center (TDC). The fuel pressure reached is around 15 x 10 6 Pa.

Or, des nouveaux dispositifs d'injection ont été développés, dans lesquels les injecteurs sont commandés par des électrovannes, sans synchronisation "mécanique" avec le cycle moteur. Il y a donc un risque que l'injection du carburant se fasse en tout point du cycle. Si une injection intempestive se produit très tôt dans la phase de compression, par exemple à 40° avant le point mort haut, ou si l'injecteur est bloqué à l'état ouvert, la pression de combustion dans la chambre peut atteindre 25 x 106 Pa à 30 x 106 Pa. Or cette pression est beaucoup trop élevée et va détériorer le moteur en pouvant provoquer notamment une torsion de bielle, un écrasement de coussinet, une fuite au joint de culasse.However, new injection devices have been developed, in which the injectors are controlled by solenoid valves, without "mechanical" synchronization with the engine cycle. There is therefore a risk that fuel injection takes place at any point in the cycle. If an untimely injection occurs very early in the compression phase, for example at 40 ° before top dead center, or if the injector is blocked in the open state, the combustion pressure in the chamber can reach 25 x 10 6 Pa at 30 x 10 6 Pa. However, this pressure is much too high and will deteriorate the engine, in particular causing torsion of the connecting rod, crushing of the bearing, leaking at the cylinder head gasket.

La présente invention a pour but de proposer un moteur du type défini plus haut, qui puisse être équipé d'injecteurs commandés par électrovanne sans risque de détérioration provoquée par une surpression dans la chambre de combustion de chaque cylindre du moteur.The object of the present invention is to provide an engine for the type defined above, which can be fitted injectors controlled by solenoid valve without risk of deterioration caused by overpressure in the combustion chamber of each engine cylinder.

Pour atteindre ce but, le moteur selon l'invention est caractérisé en ce qu'à la chambre de combustion est associé un dispositif de protection contre des surpressions dans cette chambre, apte à mettre celle-ci en communication avec un conduit d'échappement du moteur lorsque la pression régnant dans la chambre de combustion dépasse une valeur prédéterminée.To achieve this goal, the engine according to the invention is characterized in that the combustion chamber is associated a protection device against overpressures in this room, able to put it in communication with an engine exhaust duct when the pressure in the combustion chamber exceeds a predetermined value.

Selon un mode de réalisation de l'invention, le dispositif de protection contre des surpressions comprend un clapet de décharge monté dans un canal pratiqué dans la culasse du moteur et susceptible d'établir la communication précitée entre la chambre de combustion et le conduit d'échappement.According to one embodiment of the invention, the overpressure protection device includes a relief valve mounted in a channel formed in the engine cylinder head and capable of establishing the above communication between the combustion chamber and the exhaust duct.

Le clapet de décharge est formé par un organe tel qu'une bille maintenue à l'état fermé sur un siège sous l'effet d'un moyen de rappel tel qu'un ressort.The relief valve is formed by a member such as a ball kept closed on a seat under the effect a return means such as a spring.

Le canal du dispositif de protection communique, en arrière du clapet de décharge, avec le conduit d'échappement, via un canal de liaison.The protective device channel communicates, in back of the relief valve, with the conduit exhaust, via a connecting channel.

Selon un autre mode de réalisation de l'invention, selon lequel débouche dans la chambre de combustion un puits de réception d'une bougie de préchauffage qui obture le puits lorsqu'elle y est maintenue en position d'utilisation par des moyens de fixation, le dispositif de protection comprend des moyens de fixation de la bougie agencés de manière à céder sous l'action d'une surpression régnant dans la chambre de combustion et à permettre ainsi l'expulsion de la bougie et la mise en communication, par la partie libre du puits, de la chambre de combustion avec le conduit d'échappement du moteur.According to another embodiment of the invention, according to which opens into the combustion chamber a well of reception of a glow plug which blocks the well when held in position of use by fixing means, the device protection includes means for fixing the candle arranged to yield under the action of a overpressure prevailing in the combustion chamber and allow the expulsion of the candle and the setting communication, through the free part of the well, of the combustion chamber with the exhaust duct of the engine.

Selon une première variante de réalisation, les moyens de fixation de la bougie comprennent un manchon traversé par la bougie et solidaire, par exemple par vissage, de la culasse du moteur, et une rondelle élastique serrée entre une extrémité du manchon et un épaulement de la culasse et dont la partie centrale est en appui sur un épaulement de la bougie de façon à maintenir celle-ci en appui sur son siège, la partie centrale de la rondelle élastique comprenant des zones se rompant par cisaillement sous l'action de la surpression précitée.According to a first alternative embodiment, the means of candle attachment include a sleeve through the candle and secured, for example by screwing, of the engine cylinder head, and a spring washer clamped between one end of the sleeve and one shoulder of the cylinder head and whose central part is supported on a shoulder of the spark plug so as to keep it pressed on its seat, the central part of the spring washer comprising areas breaking under shear under the action of the aforementioned overpressure.

Le manchon précité comprend à son extrémité opposée à la rondelle élastique un épaulement' interne contre lequel vient en butée l'épaulement de la bougie lors de l'expulsion de celle-ci.The aforementioned sleeve comprises at its end opposite to the elastic washer an internal shoulder against which abuts the shoulder of the spark plug when the expulsion of it.

Selon une seconde variante de réalisation, la bougie comprend un manchon supérieur solidaire, par exemple par vissage, de la culasse et un corps inférieur relié au manchon par une zone annulaire frangible et propre à traverser axialement ce dernier par rupture de cette zone sous l'action de la surpression précitée.According to a second alternative embodiment, the candle includes an upper sleeve integral, for example by screwing, the cylinder head and a lower body connected to the sleeve by a frangible annular zone suitable for axially cross the latter by breaking this zone under the action of the above-mentioned overpressure.

Selon une troisième variante de réalisation, les moyens de fixation de la bougie sont du type baïonnette où le corps de la bougie comprend au moins deux ergots s'engageant respectivement dans deux rainures de maintien des ergots réalisées dans une douille cylindrique traversée par la bougie et solidaire, par exemple par vissage, de la culasse du moteur de façon à maintenir la bougie en appui sur son siège, les ergots pouvant se rompre par cisaillement de l'action de la surpression précitée.According to a third alternative embodiment, the means fixing the candle are bayonet type where the candle body includes at least two pins engaging respectively in two retaining grooves lugs made in a cylindrical socket crossed by the candle and united, for example by the engine cylinder head to maintain the candle resting on its seat, the pins can be break the action of overpressure by shearing cited above.

La partie libre du puits est reliée au conduit d'échappement par un canal de la culasse.The free part of the well is connected to the conduit exhaust through a cylinder head channel.

L'invention sera mieux comprise et d'autres buts, caractéristiques, détails et avantages de celle-ci apparaítront plus clairement au cours de la description explicative qui va suivre faite en référence aux dessins schématiques annexés donnés uniquement à titre d'exemple illustrant plusieurs modes de réalisation de l'invention et dans lesquels :

  • La figure 1 est une vue en coupe suivant la ligne I-I de la figure 3 d'une partie d'une culasse d'un moteur diesel à injecteur piloté, équipée d'un dispositif selon l'invention ;
  • La figure 2 est une vue de cette culasse, non équipée, en coupe suivant la ligne II-II de la figure 1 ;
  • La figure 3 est une vue de cette culasse non équipée suivant la flèche III de la figure 1 ;
  • La figure 4 est une vue analogue à celle de la figure 1 d'une partie de culasse d'un moteur à combustion interne à bougie de préchauffage suivant un autre mode de réalisation de l'invention ;
  • La figure 5 est une vue en coupe suivant la ligne V-V de la figure 4 ;
  • La figure 6 est une vue en bout suivant la flèche VI de la figure 4 ;
  • La figure 7 est une vue de profil d'une rondelle élastique utilisée en figure 4 ;
  • La figure 8 est une vue de dessus suivant la flèche VIII de la rondelle de la figure 7 ;
  • La figure 9 est une demi-vue en coupe semblable à celle de la figure 4 représentant encore un autre mode de réalisation de l'invention ;
  • La figure 10 est une vue agrandie en coupe longitudinale d'une bougie de préchauffage utilisée dans le mode de réalisation de la figure 9 ;
  • La figure 11 est une demi-vue en coupe semblable à celle de la figure 4 et représentant encore un autre mode de réalisation de l'invention ;
  • La figure 12 est une vue agrandie en élévation de la bougie utilisée dans le mode de réalisation de la figure 11 ;
  • La figure 13 est une vue en coupe suivant la ligne XIII-XIII de la figure 12 ;
  • La figure 14 est une vue en coupe d'un manchon de fixation de la bougie, représentée en figure 12, dans la culasse de la figure 11 ; et
  • La figure 15 est une vue de dessus suivant la flèche XV de la figure 14.
    • The invention will be better understood and other objects, characteristics, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating several modes. of the invention and in which:
  • Figure 1 is a sectional view along line II of Figure 3 of a portion of a cylinder head of a diesel engine with pilot injector, equipped with a device according to the invention;
  • Figure 2 is a view of this cylinder head, not equipped, in section along line II-II of Figure 1;
  • Figure 3 is a view of this non-equipped cylinder head according to arrow III of Figure 1;
  • Figure 4 is a view similar to that of Figure 1 of a cylinder head portion of an internal combustion engine with glow plug according to another embodiment of the invention;
  • Figure 5 is a sectional view along line VV of Figure 4;
  • Figure 6 is an end view along arrow VI of Figure 4;
  • Figure 7 is a side view of an elastic washer used in Figure 4;
  • Figure 8 is a top view along arrow VIII of the washer of Figure 7;
  • Figure 9 is a half-sectional view similar to that of Figure 4 showing yet another embodiment of the invention;
  • Figure 10 is an enlarged view in longitudinal section of a glow plug used in the embodiment of Figure 9;
  • Figure 11 is a half-sectional view similar to that of Figure 4 and showing yet another embodiment of the invention;
  • Figure 12 is an enlarged elevational view of the spark plug used in the embodiment of Figure 11;
  • Figure 13 is a sectional view along line XIII-XIII of Figure 12;
  • Figure 14 is a sectional view of a spark plug mounting sleeve, shown in Figure 12, in the cylinder head of Figure 11; and
  • FIG. 15 is a top view along arrow XV of FIG. 14.

    • En se référant à la figure 1, la référence 1 désigne une culasse de moteur à combustion interne du type diesel, à injecteurs pilotés (non représentés), fixée à des cylindres, dont un seul est représenté en 2. La référence 4 désigne une chambre de combustion délimitée entre la culasse 1 et un piston 3 et dans laquelle est directement injecté le carburant par l'injecteur piloté associé. Selon l'invention, la culasse est pourvue d'un dispositif 7 de protection contre des surpressions dans la chambre de combustion 4.Referring to Figure 1, reference 1 designates a diesel type internal combustion engine cylinder head, pilot injectors (not shown), attached to cylinders, only one of which is shown in 2. The reference 4 designates a combustion chamber delimited between the cylinder head 1 and a piston 3 and in which is directly injected fuel through the associated pilot injector. According to the invention, the cylinder head is provided with a device 7 protection against overpressure in the room combustion 4.

    Ce dispositif comprend essentiellement un clapet de décharge 8 réalisé sous forme d'une bille montée dans un canal 9 qui est pratiqué dans la culasse et débouche, à une extrémité, dans la chambre de combustion 4 et, à son autre extrémité, vers l'extérieur. Le canal comporte deux parties à section transversale circulaire, de diamètres différents. La partie débouchant dans la chambre de combustion 4 présente un diamètre plus faible. La jonction des deux parties de canal est configurée de façon à former un siège 10 pour la bille de clapet 8. Un ressort hélicoïdal 11 est prévu dans la portion de canal de plus grand diamètre et pousse la bille de clapet sur son siège en prenant appui sur un bouchon de fermeture 12 du canal.This device essentially comprises a check valve. discharge 8 produced in the form of a ball mounted in a channel 9 which is practiced in the cylinder head and opens, at one end, in the combustion chamber 4 and, at its other end, outward. The channel has two parts with circular cross-section, of diameters different. The part opening into the combustion 4 has a smaller diameter. The junction of the two channel parts is configured from so as to form a seat 10 for the valve ball 8. A coil spring 11 is provided in the channel portion larger diameter and pushes the valve ball on its seat by resting on a closure cap 12 of the canal.

    La partie de canal, située en arrière du clapet, c'est-à-dire du côté opposé de la chambre de combustion 4, communique via des canaux transversaux 14 avec des conduits d'échappement 15, comme cela est montré sur la figure 2, qui débouchent dans la chambre de combustion 4, de façon usuelle, chacun par un orifice 16 obturable cycliquement par une soupape non représentée ici. La figure 3 montre la disposition relative du canal 9 qui loge le clapet de surcharge 8 et les deux conduits d'échappement 15 figurant sur la figure 2.The channel part, located behind the valve, i.e. on the opposite side of the combustion chamber 4, communicates via transverse channels 14 with exhaust pipes 15, as shown on the FIG. 2, which open into the combustion chamber 4, in the usual way, each by a closable orifice 16 cyclically by a valve not shown here. The Figure 3 shows the relative arrangement of channel 9 which houses the overload valve 8 and the two conduits exhaust 15 shown in Figure 2.

    Concernant le fonctionnement du dispositif de protection 8, lors d'une combustion normale, la bille 8 est maintenue sur son siège 10 sous l'action du ressort 11. Lorsqu'une surpression se produit dans la chambre de combustion 4, qui dépasse le seuil de pression déterminé par le ressort, la bille 8 se soulève de son siège à l'encontre du ressort, ce qui met la chambre de combustion 4 en communication avec les conduits d'échappement 15, via les canaux 9 et 14. Grâce à cette communication, la surpression dans la chambre 4 est éliminée ou même évitée.Regarding the operation of the protection device 8, during normal combustion, the ball 8 is maintained on its seat 10 under the action of the spring 11. When an overpressure occurs in the combustion 4, which exceeds the determined pressure threshold by the spring, the ball 8 lifts from its seat at against the spring, which puts the combustion 4 in communication with the conduits exhaust 15, via channels 9 and 14. Thanks to this communication, the overpressure in room 4 is eliminated or even avoided.

    Bien entendu, diverses modifications peuvent être apportées à l'invention telle qu'elle vient d'être décrite en se référant aux figures 1 à 3. Par exemple, la bille pourrait être remplacée par un piston, et les canaux de liaison 14 peuvent déboucher dans tout autre conduit d'échappement que ceux débouchant dans la chambre de combustion à laquelle le dispositif de protection est associé.Of course, various modifications can be made to the invention as it has just been described with reference to Figures 1 to 3. For example, the ball could be replaced by a piston, and the connecting channels 14 can lead into any other exhaust pipe as those opening into the room of combustion to which the protective device is associated.

    Selon le mode de réalisation du dispositif de protection représenté aux figures 4 à 8 où les parties identiques à celles des figures 1 à 3 portent les mêmes références, la culasse 1 comprend, pour chacune des chambres de combustion 4, un puits 17 débouchant dans la chambre 4 et recevant une bougie de préchauffage 18 qui obture le puits 17 lorsqu'elle est maintenue dans celui-ci pour son utilisation par des moyens de fixation. La bougie 18 a son électrode centrale 19 faisant saillie dans la chambre de combustion 4 de manière à réchauffer le carburant lors du démarrage du moteur.According to the embodiment of the protection device shown in Figures 4 to 8 where the parts identical to those of FIGS. 1 to 3 bear the same references, the cylinder head 1 includes, for each of the combustion 4, a well 17 opening into chamber 4 and receiving a glow plug 18 which closes the well 17 when held in it for its use by fixing means. The candle 18 a its central electrode 19 projecting into the chamber combustion 4 so as to heat the fuel during starting the engine.

    Selon ce mode de réalisation, les moyens de fixation de la bougie 18 comprennent un manchon 20 traversé par la bougie 18 et solidaire de la culasse 1, par exemple en étant vissé dans un trou taraudé correspondant 21 de la culasse 1 et coaxial au puits 17. Ces moyens de fixation comprennent également une rondelle élastique 22 montée entre une extrémité inférieure du manchon 20 et un épaulement 1a de la culasse 1 de façon à être serrée sur l'épaulement 1a par le manchon 20. La figure 7 représente la rondelle élastique 22 à l'état libre et la figure 8 montre que cette rondelle a sa partie centrale constituée d'un certain nombre d'ailettes radiales 22a, par exemple au nombre de trois, venant en appui, en position montée, sur un épaulement 18a du corps de la bougie 18 de façon à maintenir celle-ci en appui sur son siège 1b de la culasse 1.According to this embodiment, the means for fixing the candle 18 include a sleeve 20 through which the spark plug 18 and integral with the cylinder head 1, for example in being screwed into a corresponding tapped hole 21 of the cylinder head 1 and coaxial with well 17. These fixing means also include a spring washer 22 mounted between a lower end of the sleeve 20 and a shoulder 1a of cylinder head 1 so as to be tightened on the shoulder 1a by the sleeve 20. FIG. 7 represents the elastic washer 22 in the free state and FIG. 8 shows that this washer has its central part made up of a number of radial fins 22a, for example three in number, bearing, in the mounted position, on a shoulder 18a of the body of the candle 18 so as to keep it supported on its seat 1b of the cylinder head 1.

    Les ailettes 22a de la rondelle 22 sont reliées au corps de celle-ci par des zones z1 pouvant se rompre par cisaillement comme cela va être décrit maintenant.The fins 22a of the washer 22 are connected to the body of the latter by zones z 1 which can rupture by shearing as will now be described.

    En effet, lorsque la pression régnant dans la chambre de combustion 4 est supérieure à une valeur maximale atteinte en fonctionnement normal du moteur et en particulier de l'injection pilotée, une telle surpression est appliquée à l'extrémité inférieure de la bougie 18 et la rondelle 22 se rompt par cisaillement dans les zones z1 prévues à cet effet, de sorte que la bougie 18 est expulsée vers l'extérieur. La figure 4 montre en demi-vue axiale inférieure la bougie 18 en position d'utilisation dans la culasse et en demi-vue axiale supérieure la bougie 18 expulsée. Lors de l'expulsion de la bougie 18, l'épaulement 18a du corps de celle-ci vient en appui sur un épaulement interne du manchon 20 opposé à la rondelle 22 par l'intermédiaire d'un joint métallique 23. En position expulsée de la bougie 18, la surpression dans la chambre 4 est évitée ou interrompue par évacuation des gaz de la chambre de combustion vers les conduits d'échappement C1 et C2 via des canaux 24 réalisés dans la culasse 1. Le joint 23 élimine par ailleurs des risques de fuite de gaz lors de la surpression et également en fonctionnement normal tout en protégeant la bougie 18 contre les vibrations. In fact, when the pressure prevailing in the combustion chamber 4 is greater than a maximum value reached in normal operation of the engine and in particular of the controlled injection, such overpressure is applied to the lower end of the spark plug 18 and the washer 22 is broken by shearing in the zones z 1 provided for this purpose, so that the plug 18 is expelled outwards. Figure 4 shows in lower axial half-view the spark plug 18 in the position of use in the cylinder head and in upper axial half-view the spark plug 18 expelled. During the expulsion of the spark plug 18, the shoulder 18a of the body thereof comes to bear on an internal shoulder of the sleeve 20 opposite the washer 22 by means of a metal seal 23. In the expelled position of the spark plug 18, the overpressure in the chamber 4 is avoided or interrupted by evacuation of the gases from the combustion chamber towards the exhaust conduits C1 and C2 via channels 24 produced in the cylinder head 1. The seal 23 also eliminates risks gas leakage during overpressure and also in normal operation while protecting the spark plug 18 against vibration.

    Les figures 9 et 10 représentent un troisième mode de réalisation permettant l'expulsion d'une bougie de préchauffage lors d'une surpression dans la chambre de combustion 4. Les parties des figures 9 et 10 communes à celles des figures 4 et 5 portent les mêmes références.Figures 9 and 10 show a third mode of realization allowing the expulsion of a candle preheating during an overpressure in the combustion 4. The parts of Figures 9 and 10 common to those of FIGS. 4 and 5 bear the same references.

    Selon ce troisième mode de réalisation, la bougie 18 comprend un manchon supérieur 25 solidaire de la culasse 1, par exemple par vissage dans un trou taraudé correspondant 26 de la culasse 1 coaxial au puits 17 de réception de la bougie 18, et un corps inférieur 18b relié au manchon 25 par une zone annulaire frangible z2 et propre à traverser axialement ce dernier par rupture de la zone frangible z2. La zone annulaire z2 peut se rompre lors d'une surpression régnant dans la chambre de combustion 4 de façon à expulser vers l'extérieur la bougie 18 comme représenté en figure 9 en demi-vue axiale inférieure de la bougie 18. En position expulsée de la bougie 18, la partie libre du puits 17 communique, par l'intermédiaire d'un canal 24 de la culasse 1, avec au moins un circuit d'échappement de façon à évacuer les gaz de surpression de la chambre de combustion 4.According to this third embodiment, the candle 18 includes an upper sleeve 25 integral with the cylinder head 1, for example by screwing into a tapped hole corresponding 26 of the cylinder head 1 coaxial to the well 17 of reception of the candle 18, and a lower body 18b connected to the sleeve 25 by a frangible annular zone z2 and capable of crossing the latter axially by rupture of the frangible zone z2. The annular zone z2 can be rupture during an overpressure prevailing in the combustion 4 so as to expel outwards the candle 18 as shown in FIG. 9 in axial half-view lower part of the spark plug 18. In the position expelled from the candle 18, the free part of the well 17 communicates, by through a channel 24 of the cylinder head 1, with at minus an exhaust system to evacuate gases overpressure of the combustion chamber 4.

    Suivant le mode de réalisation représenté aux figures 11 à 15, où les éléments identiques à ceux des figures 4 et 5 portent les mêmes références, les moyens de fixation de la bougie 18 dans le puits 17 de la culasse 1 sont du type baïonnette, c'est-à-dire comprenant au moins deux ergots 27 solidaires du corps de la bougie 18 et une douille cylindrique 28 traversée par la bougie 18 en étant solidaire de la culasse 1, par exemple par vissage dans un trou taraudé correspondant 29 de la culasse 1, la douille 28 comprenant deux rainures 28a, 28b conformées de façon à permettre un engagement axial des ergots 27 dans celles-ci, puis par rotation du corps de la bougie 18, l'engagement des ergots 28 dans les parties curvilignes des rainures 28a, 28b jusqu'à venir en butée contre les parois extrêmes de celles-ci, bloquant ainsi la bougie 18 relativement à la culasse 1 pour maintenir la bougie en appui sur son siège 1b.According to the embodiment shown in Figures 11 to 15, where the elements identical to those of FIGS. 4 and 5 bear the same references, the means for fixing the candle 18 in the well 17 of the cylinder head 1 are bayonet type, i.e. comprising at least two pins 27 secured to the body of the spark plug 18 and one cylindrical socket 28 through which the candle 18 passes being integral with the cylinder head 1, for example by screwing in a corresponding tapped hole 29 of cylinder head 1, the socket 28 comprising two grooves 28a, 28b shaped so as to allow axial engagement of the pins 27 in these and then by rotating the body of the candle 18, the engagement of the pins 28 in the parts curvilinear grooves 28a, 28b until they stop against the extreme walls thereof, thereby blocking the candle 18 relative to the cylinder head 1 to maintain the candle resting on its seat 1b.

    Les ergots 28 peuvent se rompre par cisaillement sous l'action d'une surpression éventuelle régnant dans la chambre de combustion 4 de façon à expulser la bougie 18 comme représenté en figure 11 sur la demi-vue axiale inférieure de la bougie 18. Lorsque la bougie 18 est expulsée, la partie libre du puits 17 communique avec au moins un circuit d'échappement par un canal 24 de la culasse 1 identique à celui représenté en figure 9.The pins 28 can break by shearing under the action of a possible overpressure prevailing in the combustion chamber 4 so as to expel the candle 18 as shown in figure 11 on the axial half-view lower part of the spark plug 18. When the spark plug 18 is expelled, the free part of the well 17 communicates with at minus an exhaust system through a channel 24 of the cylinder head 1 identical to that shown in FIG. 9.

    L'invention ci-dessus décrite dans les trois modes de réalisation permet une protection efficace du moteur contre une détérioration provoquée par une éventuelle surpression anormale dans au moins une des chambres de combustion du moteur en expulsant la ou chaque bougie de préchauffage correspondante et en évacuant les gaz de surpression par un canal de décharge.The invention described above in the three modes of construction provides effective motor protection against deterioration caused by possible abnormal overpressure in at least one of the combustion of the engine by expelling the or each spark plug corresponding preheating and evacuating the gases from overpressure by a discharge channel.

    Claims (10)

    1. Internal combustion engine with piloted injection of fuel, directly in at least one combustion chamber provided with at least one exhaust duct port which is cyclically obturated by a valve, characterized in that the combustion chamber (4) is operatively associated with a device (7) for protecting against excessive pressures in this chamber, able to put the same into communication with an exhaust duct (15; C1, C2) of the motor when the pressure prevailing in the combustion chamber (4) exceeds a predetermined value.
    2. Motor according the claim 1, characterized in that the above-mentioned device (7) for protecting against excessive pressures comprises a discharge flap (8) which is mounted in a channel (9) provided in the yoke (1) of the motor and capable of establishing the above-mentioned communication between the combustion chamber (4) and the exhaust duct (15).
    3. Motor according the claim 2, characterized in that the discharge flap (8) is formed by a member such as a ball which is maintained closed on a seat (10) under a return means such as a spring (11).
    4. Motor according to one of claims 2 or 3, characterized in that the channel (9) of the protecting device (7) communicates, rearwardly of the discharge flap, with the exhaust duct (15), via a connecting channel (14).
    5. Motor according to claim 1, of the type in which in particular a well (17) opens into the combustion chamber (4), this well (17) being provided for receiving a preheating plug (18) which obturates the well (17) when it is maintained in the use position by fixation means, characterized in that the above-mentioned protection device comprises fixation means for the plug (18) arranged in order to give up under action of an excessive pressure prevailing in the combustion chamber (4) and thus allow expulsion of the plug (18) and communication, through the free portion of the well (17), of the combustion chamber (4) with the exhaust duct of the motor.
    6. Motor according the claim 5, characterized in that the means for fixing the plug (18) comprise a sleeve (20) crossed through by the plug (18) and rigidly connected, for example by screwing, with the yoke (1) of the motor, and an elastic washer (22) squeezed between a lower end of the sleeve (20) and a shoulder (1a) of the yoke (1) and a central part of which is supported by a shoulder (18a) of the plug (18) in order to maintain it supported on its seat (1b), the central part of the elastic washer (22) comprising areas (z1) which are shearingly broken under the above-mentioned excessive pressure.
    7. Motor according claim 6, characterized in that the above-mentioned sleeve (20) comprises an end opposite the elastic washer (22) and which is provided with an inner shoulder on which the shoulder (18a) of the plug (18) comes into abutment upon the expulsion thereof.
    8. Motor according claim 5, characterized in that the plug (18) comprises an upper sleeve (25) which is rigidly connected , for example by screwing, with the yoke and a lower body (18b) connected to the sleeve (25) by a breakable annular area (z2) able to axially pass through the same by breakage of this area (z2) under the above-mentioned excessive pressure.
    9. Motor according claim 5, characterized in that the means for fixing the plug (18) are of the bayonet type wherein the body of the plug (18) comprises at least two snugs (28) engaging respectively two grooves (18a, 18b) for maintaining the snugs (28) made in a cylindrical socket (29) crossed through by the plug (18) and rigidly connected, for example by screwing, with the yoke (1) of the motor in order to maintain the plug (18) supported on its seat (1b), the snugs (28) being shearingly breakable under the above-mentioned excessive pressure.
    10. Motor according to one of claims 5 to 9, characterized in that the free portion of the well (7) is connected to the exhaust duct (C1, C2) by means of a channel (24) of the yoke.
    EP19970400943 1996-05-03 1997-04-25 Internal combustion engine with pilot injection Expired - Lifetime EP0805266B1 (en)

    Applications Claiming Priority (4)

    Application Number Priority Date Filing Date Title
    FR9605580 1996-05-03
    FR9605580A FR2748295B1 (en) 1996-05-03 1996-05-03 INTERNAL COMBUSTION ENGINE HAS AT LEAST ONE EXPULSIBLE SPARK PLUG
    FR9606012A FR2748777B1 (en) 1996-05-14 1996-05-14 INTERNAL COMBUSTION ENGINE WITH PILOT FUEL INJECTION
    FR9606012 1996-05-14

    Publications (2)

    Publication Number Publication Date
    EP0805266A1 EP0805266A1 (en) 1997-11-05
    EP0805266B1 true EP0805266B1 (en) 2001-11-14

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    Family Applications (1)

    Application Number Title Priority Date Filing Date
    EP19970400943 Expired - Lifetime EP0805266B1 (en) 1996-05-03 1997-04-25 Internal combustion engine with pilot injection

    Country Status (3)

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    EP (1) EP0805266B1 (en)
    DE (1) DE69708199T2 (en)
    ES (1) ES2166512T3 (en)

    Families Citing this family (2)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    DE19743061A1 (en) * 1997-09-30 1999-04-01 Bosch Gmbh Robert Method for operating an internal combustion engine and fuel injection system for carrying out the method
    GB0004271D0 (en) * 2000-02-23 2000-04-12 Bastable Richard A Recirculated compression direct gas injection system

    Family Cites Families (7)

    * Cited by examiner, † Cited by third party
    Publication number Priority date Publication date Assignee Title
    US2922436A (en) * 1956-09-07 1960-01-26 Gen Motors Corp Combined test and safety valve
    DE3003864A1 (en) * 1980-02-02 1981-08-13 Klöckner-Humboldt-Deutz AG, 5000 Köln Water-cooled engine cylinder head - has safety valve outlet connected by pipe to spark-arrester chamber
    DE3622261C2 (en) * 1985-07-12 1998-07-02 Volkswagen Ag Glow plug to facilitate cold starting for an internal combustion engine
    SU1379493A1 (en) * 1986-10-28 1988-03-07 Ю.Ф.Кирюшкин и Д.А.Демин Glow plug of retracting type for diesel engine
    GB2217386A (en) * 1988-04-08 1989-10-25 Ford Motor Co Diesel engine glowplug installation
    JPH05118946A (en) * 1991-10-23 1993-05-14 Ngk Spark Plug Co Ltd Device for detecting pressure inside of cylinder
    JPH04335126A (en) * 1991-05-10 1992-11-24 Matsushita Electric Ind Co Ltd Internal pressure sensor

    Also Published As

    Publication number Publication date
    DE69708199T2 (en) 2002-09-12
    EP0805266A1 (en) 1997-11-05
    ES2166512T3 (en) 2002-04-16
    DE69708199D1 (en) 2001-12-20

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