EP0069416B1 - Carburettor for internal-combustion engines - Google Patents

Carburettor for internal-combustion engines Download PDF

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Publication number
EP0069416B1
EP0069416B1 EP82200759A EP82200759A EP0069416B1 EP 0069416 B1 EP0069416 B1 EP 0069416B1 EP 82200759 A EP82200759 A EP 82200759A EP 82200759 A EP82200759 A EP 82200759A EP 0069416 B1 EP0069416 B1 EP 0069416B1
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EP
European Patent Office
Prior art keywords
carburetor
diffusers
diffuser
disposed
shutter
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Expired
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EP82200759A
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German (de)
French (fr)
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EP0069416A2 (en
EP0069416A3 (en
Inventor
Marco Dr. Ing. Morini
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Individual
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Individual
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Publication of EP0069416A3 publication Critical patent/EP0069416A3/en
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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
    • F02M11/00—Multi-stage carburettors, Register-type carburettors, i.e. with slidable or rotatable throttling valves in which a plurality of fuel nozzles, other than only an idling nozzle and a main one, are sequentially exposed to air stream by throttling valve
    • F02M11/10—Register carburettors with rotatable throttling valves
    • 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
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four

Definitions

  • the subject of the present invention is a carburetor for Otto cycle engines, of the type in which the fuel is kept at a constant level in a tank and it is introduced into the air flow drawn in by the engine by the effect of the vacuum produced. by the flow in the restricted section of a Venturi tube diffuser.
  • Carburettors with several diffusers aligned one next to the other have also been proposed, cooperating with a shutter which can be moved in a straight line to discover them one after the other.
  • Said diffusers can be singularly sized (FR-A-647181) and they can be supplied by a constant level tank of the overflow type arranged laterally (FR-E-43 573).
  • FR-A-647181 FR-A-647181
  • FR-E-43 573 constant level tank of the overflow type arranged laterally
  • the arrangement of the diffusers aligned one next to the other gives rise to excessive bulk, the control of a shutter moving in a straight line is not practical, and the lateral arrangement of the tank, at a considerable distance from the farthest diffusers, gives rise to supply irregularities when the device is in an inclined position.
  • diffusers are arranged in arcs, which can be opposite, and they cooperate with a rotary shutter formed by a disc with openings which reveal the diffusers one after another.
  • the shutter disposed downstream of the diffusers, supports over its entire surface a thrust generated by the supply vacuum; consequently, it is of massive construction, which however prejudges the flexibility and the speed of operation.
  • we could not give it a lighter construction because the structure of the carburetor does not give shoulders to these shutters, and the thrust applied by the depression on a thin shutter would give rise to deformations by compromising the tightness and therefore the accuracy of the adjustment.
  • the object of the invention is to provide a carburetor capable of maintaining a well-controlled supply under all operating conditions, so as to ensure maximum efficiency, best combustion and minimization of atmospheric pollution, while avoiding indicated disadvantages of known carburetors.
  • a carburetor having the characteristics set out in claim 1. Because the rotary shutter is disposed between the body of the carburetor and the distributor, it is effectively supported against the thrust generated by the vacuum.
  • the tank placed in the central area of the body makes good use of the space left free by the diffusers arranged on opposite arcs.
  • the arched tanks connected to the constant level tank, and in which the tubes of the diffusers submerge, ensure in all conditions a correct supply.
  • the rotary shutter can be thin and light and is easy to maneuver.
  • FIGS. 6 and 7 show details in partial vertical sections made respectively along the line VI-VI and along the line VII-VII of FIG. 3.
  • the example shown refers to a reverse flow carburetor, with seven diffusers arranged in arcs of a circle and cooperating with a rotary shutter, with overflow tank, device for operating at minimum and recovery pump, but, as already said, these choices should not be considered as limiting the scope of the invention.
  • the structure of the carburetor shown mainly comprises a body 1, a distributor 2 arranged below the body 1, a manifold 4 and a cover 5.
  • the latter is applied to the body 1 by means of screws not shown, with the interposition of 'A flat seal 27;
  • the distributor 2 is fixed to the body 1 by teeth with elastic trigger 36 and with the interposition of a toroidal sealing gasket 37;
  • the manifold 4 is fixed to the distributor 2 by means of teeth with elastic release 38 and with the interposition of a toroidal sealing gasket 39.
  • these connection systems assume that the distributor 2 is formed of plastic material , which is made possible by the adoption of the principles of the invention.
  • the manifold 4 is intended to be shown on the suction manifold (not shown) of a carburetion engine, and above the cover 5 is intended to be mounted a suction air filter; to fix the latter's box, the cover 5 has threaded rods 25; the air filter is not shown.
  • the body 1 is traversed by a plurality of diffusers 6, in this case in number of seven, distributed over a circumference and forming two groups, respectively of four and three diffusers.
  • a small tube opens. 12 suitably curved, at the opposite end of which a nozzle is applied 11.
  • the various nozzles 11 of the two groups of diffusers sink into respective tanks 35 and 34 which, through conduits 33 and 32, communicate with a central tank at constant level 30.
  • This tank is supplied by the usual supply pump (not shown) through a connector 13, a fuel filter 15 and a flow metering nozzle 16.
  • the constant level is ensured by a weir 7, and the fuel supplied in excess is poured into an arcuate tank 31, from which it passes to a connector 14 intended to be connected to a recovery pump (not shown), which returns the unused fuel to the tank. Thanks to communications 32 and 33, the same constant level of the tank 30 is also established in the tanks 34 and 35 and submerges, with a preset load, the nozzles 11 of the tubes 12.
  • a rotary shutter formed by a disc 3 provided with two arcuate slots 18 and 19. These slots are arranged so that, in a position of the disc 3 (full opening), they leave all free the diffusers 6 of the two groups, in another position (total closure) they close all the diffusers, and, passing from this last position to the first, they first gradually discover the first diffuser 6 '(belonging to the first group) and_then, after having completely opened this first diffuser, they discover the second 6 "diffuser (belonging to the second group), then the third 6"'diffuser (belonging again to the first group) and so on.
  • the diffusers 6 are illustrated as all equal, they may have different sections or / and they may be served by nozzles 11 of different caliber, so as to obtain the best dosage for each operating regime .
  • the slots 18 and 19 of the shutter 3 ′ may have any other profile in order to obtain a desired law of variation of the total passage section according to the control of the accelerator, this law can be approximately linear, exponential or other, to obtain the best maneuverability of the engine.
  • the rotary shutter 3 is controlled by. by means of a shaft 20, which passes through the body 1 and the cover 5 and which, above the latter, is connected to a lever 21 returned to the minimum position by a spring 23 supported on a relief 42 of the cover 5. To the lever 21 will be hooked the bowden or other acceleration control transmission, not shown, acting substantially along the line with dots and lines 43 of FIG. 1.
  • a toroidal seal 22 establishes the seal between the small shaft 20 and body 1.
  • Operation at minimum regime, in a carburetor according to the invention can be made correct by providing a first diffuser particularly designed for this operation, and in this case no special device should be provided for this purpose.
  • a special minimum device such as that shown in Figures 1 and 7 can be adopted.
  • one is derived from one of the fuel supply tanks (in the example, the tank 34) a conduit 10 which carries the fuel to an air passage 9 provided for this purpose through the body 1, the distributor 2 and the cover 5.
  • the conduit 10 can be more or less throttled by means of a screw needle 26, and the air passage 9 can also be more or less throttled by means of an adjusting screw 17.
  • the operation at minimum speed can therefore be conveniently adjusted by means of the screws 17 and 26.
  • the passage 9 can be opened permanently, since its cross section is negligible for operation at higher speeds, or it can be conveniently occluded by the rotary shutter 3, from a determined supply speed.
  • the recovery pump comprises a piston 28 inserted, without sealing, in a cylinder 8 formed in the body 1, adjacent and in communication, above a wall 44, with the central tank 30 at constant level.
  • a conduit 45 which, through a non-return valve 29, opens into the first diffuser 6.
  • the piston 28 is pushed upwards by a spring 46 and it is connected to a rod 47 which forms a pusher against a front cam 48 presented below by the lever 21 for controlling the rotary shutter. Therefore, when the shutter is rotated in the direction of increasing the opening of the diffusers, the rod 47 with the piston 28 is lowered. Since the piston does not seal, if the maneuver is slow there is no backflow, but if the maneuver is rapid, fuel is pushed into the duct 45 and is poured into the first diffuser 6, thus providing the supply stronger demanded by rapid acceleration.
  • the device for the cold start when requested, can be simply constituted by a flat element 24 pivoted on the shaft 20 and sliding on the cover 5 under the control of a tie rod, not shown, arranged according to the line with dots and lines 50 of FIG. 1.
  • the movement of the element 24 is limited, by stops 49 formed by the cover 5, between two positions, in one of which (normal operation) the element 24 does not interfere not with the diffusers 6, while in the other position (cold start) the element 24 partially closes the first diffuser 6.
  • the cover 5 is predisposed to receive thereon the body of an air filter. But it is also possible to shape the cover 5 so that it itself forms the seat for the application of a filter cartridge for the aspirated air, thus avoiding providing the carburetor with a special body for the filter and simplifying assembly operations.
  • the application of the present invention allows the adoption of forms particularly suitable for manufacturing in molded synthetic material, but when requested the parts of the carburetor according to the invention can be produced with another material, such as zamak (alloy zinc and aluminum) or a light alloy, by die-casting.
  • zamak alloy zinc and aluminum
  • a light alloy by die-casting.
  • the carburetor can be provided with any other kind of constant level tank, for example with float.
  • the number of diffusers which in the example is seven, can naturally vary from a minimum of three to a maximum determined by the overall dimensions accepted for the carburetor.
  • the angular distance between successive diffusers can be chosen differently, and it can be uniform or even different for the various diffusers.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)
  • Means For Warming Up And Starting Carburetors (AREA)

Description

La présente invention a pour objet un carburateur pour moteurs à cycle Otto, du type dans lequel le carburant est maintenu à un niveau constant dans une cuve et il est introduit dans le flux d'air.aspiré par le moteur par effet de ia dépression produite par le flux dans la section restreinte d'un diffuseur à tube de Venturi.The subject of the present invention is a carburetor for Otto cycle engines, of the type in which the fuel is kept at a constant level in a tank and it is introduced into the air flow drawn in by the engine by the effect of the vacuum produced. by the flow in the restricted section of a Venturi tube diffuser.

Dans les carburateurs connus à un seul corps, le réglage de la vitesse du moteur est effectué au moyen d!utle vanne papillon qui étrangle en mesure variable le conduit d'aspiration en aval du diffuseur. Dans la plupart des conditions de fonctionnement, le flux résulte donc étranglé et sa vitesse dans le diffuseur n'a pas sa valeur optimale qui produit les conditions plus favorables de mélange. Par cette raison et par le fait que le gicleur du jet est invariable, il est impossible de réaliser, pour toutes les conditions de fonctionnement, l'alimentation la plus rationnelle du carburant, et on doit accepter des compromis qui causent, dans l'ensemble du fonctionnement, des plus mauvaises combustions et une augmentation de la pollution atmosphérique.In known carburetors with only one body, the adjustment of the engine speed is effected by means of ! use the butterfly valve which throttles the suction duct downstream of the diffuser in variable measure. Under most operating conditions, the flow therefore results in throttling and its speed in the diffuser does not have its optimum value which produces the most favorable conditions for mixing. For this reason and the fact that the jet nozzle is invariable, it is impossible to achieve, for all operating conditions, the most rational supply of fuel, and we must accept compromises which cause, on the whole of operation, worse combustion and an increase in air pollution.

Une amélioration de cette situation est obtenue avec les carburateurs à double corps, dans lesquels un premier corps de carburateur contrôle le fonctionnement du moteur dans le champ des petites vitesses, pendant que le second corps est inactif, tandis qu'à partir d'une condition déterminée le premier corps continue son fonctionnement sans étranglement et le réglage est confié au second corps, qui agit en parallèle avec le premier. Mais, même dans ce cas, il y a un grand nombre de conditions de fonctionnement dans lesquelles une importante fraction de carburant est introduite dans un diffuseur qui est très étranglé et qui cause une perte de rendement, une mauvaise combustion et bien de pollution.An improvement of this situation is obtained with double body carburetors, in which a first carburetor body controls the operation of the engine in the low speed field, while the second body is inactive, while from a condition determined the first body continues its operation without throttling and the adjustment is entrusted to the second body, which acts in parallel with the first. But, even in this case, there are a large number of operating conditions in which a large fraction of fuel is introduced into a diffuser which is very strangled and which causes a loss of efficiency, poor combustion and good pollution.

On a aussi proposé des carburateurs à plusieurs diffuseurs alignés l'un à côté de l'autre, coopérant avec un obturateur qui peut être déplacé en ligne droite pour les découvrir l'un après l'autre. Lesdits diffuseurs peuvent être singulièrement dimensionnés (FR-A-647181) et ils peuvent être alimentés par une cuve à niveau constant du type à déversoir disposée latéralement (FR-E-43 573). Toutefois, la disposition des diffuseurs alignés l'un à côté de l'autre donne lieu à un encombrement excessif, la commande d'un obturateur se déplaçant en ligne droite n'est pas pratique, et la disposition latérale de la cuve, à une distance considérable des diffuseurs les plus loins, donne lieu à des irrégularités d'alimentation lors que le dispositif se dispose en position inclinée.Carburettors with several diffusers aligned one next to the other have also been proposed, cooperating with a shutter which can be moved in a straight line to discover them one after the other. Said diffusers can be singularly sized (FR-A-647181) and they can be supplied by a constant level tank of the overflow type arranged laterally (FR-E-43 573). However, the arrangement of the diffusers aligned one next to the other gives rise to excessive bulk, the control of a shutter moving in a straight line is not practical, and the lateral arrangement of the tank, at a considerable distance from the farthest diffusers, gives rise to supply irregularities when the device is in an inclined position.

Suivant les brevets FR-A-488209 et FR-A-437 972, des diffuseurs sont disposés suivant des arcs, qui peuvent être opposés, et ils coopèrent avec un obturateur tournant formé par un disque avec des ouvertures qui découvrent les diffuseurs l'un après l'autre. Toutefois l'obturateur, disposé en aval des diffuseurs, supporte sur toute sa surface une poussée engendrée par la dépression d'alimentation ; par conséquence, il est de construction massive, ce qui toutefois préjuge de la souplesse et de la rapidité de manoeuvre. D'un autre côté on ne pourrait pas lui donner une construction plus légère parce que la structure du carburateur ne donne pas d'épaulement à ces obturateurs, et la poussée appliquée par la dépression sur un obturateur mince donnerait lieu à des déformations en compromettant l'étanchéité et donc l'exactitude du réglage.According to the patents FR-A-488209 and FR-A-437 972, diffusers are arranged in arcs, which can be opposite, and they cooperate with a rotary shutter formed by a disc with openings which reveal the diffusers one after another. However, the shutter, disposed downstream of the diffusers, supports over its entire surface a thrust generated by the supply vacuum; consequently, it is of massive construction, which however prejudges the flexibility and the speed of operation. On the other hand we could not give it a lighter construction because the structure of the carburetor does not give shoulders to these shutters, and the thrust applied by the depression on a thin shutter would give rise to deformations by compromising the tightness and therefore the accuracy of the adjustment.

Le but de l'invention est de réaliser un carburateur capable de maintenir en toutes les conditions de fonctionnement une alimentation bien contrôlée, de manière à assurer le rendement maximal, la meilleure combustion et la réduction au minimum de la pollution atmosphérique, tout en évitant les inconvénients indiqués des carburateurs connus.The object of the invention is to provide a carburetor capable of maintaining a well-controlled supply under all operating conditions, so as to ensure maximum efficiency, best combustion and minimization of atmospheric pollution, while avoiding indicated disadvantages of known carburetors.

Ce but est atteint par un carburateur ayant les caractéristiques exposées dans la revendication 1. Du fait que l'obturateur tournant est disposé entre le corps du carburateur et le distributeur, il est appuyé de façon efficace contre la poussée engendrée par la dépression. La cuve disposée dans la zone centrale du corps utilise bien l'espace laissé libre par les diffuseurs disposés sur des arcs opposés. Les cuves arquées reliées à la cuve à niveau constant, et dans lesquelles submergent les tubes des diffuseurs, assurent en toute condition une alimentation correcte. L'obturateur tournant peut être mince et léger et il est facile à manoeuvrer.This object is achieved by a carburetor having the characteristics set out in claim 1. Because the rotary shutter is disposed between the body of the carburetor and the distributor, it is effectively supported against the thrust generated by the vacuum. The tank placed in the central area of the body makes good use of the space left free by the diffusers arranged on opposite arcs. The arched tanks connected to the constant level tank, and in which the tubes of the diffusers submerge, ensure in all conditions a correct supply. The rotary shutter can be thin and light and is easy to maneuver.

Des autres caractéristiques préférées, qui s'ajoutent favorablement à celles suivant la revendication 1, sont exposées dans les sous-revendications.Other preferred features which are favorably added to those according to claim 1 are set out in the dependent claims.

Les caractéristiques et les avantages de la présente invention résulteront plus clairement de la suivante description d'une forme particulière de réalisation, indiquée à titre d'exemple non limitatif, et schématiquement représentée dans les dessins annexés, dans lesquels :

  • la figure 1 représente une vue en plan du carburateur selon l'invention, privé du filtre d'air habituellement placé sur le carburateur ;
  • la figure 2 montre une section verticale faite selon la ligne brisée II-II de la figure 1 ;
  • la figure 3 montre le carburateur en plan après enlèvement des parties qui se trouvent au-dessus de la ligne III-III de la figure 2 ;
  • la figure 4 montre le carburateur en plan après enlèvement des parties qui se trouvent au-dessus de la ligne IV-IV de la figure 2 ;
  • la figure 5 montre une section verticale partielle faite selon la ligne V-V de la figure 1 ;
The characteristics and advantages of the present invention will result more clearly from the following description of a particular embodiment, indicated by way of nonlimiting example, and schematically represented in the appended drawings, in which:
  • FIG. 1 represents a plan view of the carburetor according to the invention, deprived of the air filter usually placed on the carburetor;
  • Figure 2 shows a vertical section made along the broken line II-II of Figure 1;
  • Figure 3 shows the carburetor in plan after removal of the parts which are above the line III-III of Figure 2;
  • Figure 4 shows the carburetor in plan after removal of the parts which are above the line IV-IV of Figure 2;
  • Figure 5 shows a partial vertical section taken along the line VV of Figure 1;

les figures 6 et 7 montrent des détails en des sections verticales partielles faites respectivement selon la ligne VI-VI et selon la ligne VII-VII de la figure 3.FIGS. 6 and 7 show details in partial vertical sections made respectively along the line VI-VI and along the line VII-VII of FIG. 3.

L'exemple représenté se réfère à un carburateur à flux inversé, à sept diffuseurs disposés selon des arcs de cercle et coopérant avec un obturateur tournant, avec cuve à débordement, dispositif pour le fonctionnement au minimum et pompe de reprise, mais, comme on l'a déjà dit, ces choix ne doivent pas être considérés limitatifs du domaine de l'invention..The example shown refers to a reverse flow carburetor, with seven diffusers arranged in arcs of a circle and cooperating with a rotary shutter, with overflow tank, device for operating at minimum and recovery pump, but, as already said, these choices should not be considered as limiting the scope of the invention.

La structure du carburateur représenté comprend principalement un corps 1, un distributeur 2 disposé au-dessous du corps 1, un collecteur 4 et un couvercle 5. Ce dernier est appliqué sur le corps 1 au moyen de vis non représentées, avec l'interposition d'une garniture plane d'étanchéité 27 ; le distributeur 2 est fixé au corps 1 par des dents à déclenchement élastique 36 et avec l'interposition d'une garniture toroïdale d'étanchéité 37 ; le collecteur 4 est fixé au distributeur 2 au moyen de dents à déclenchement élastique 38 et avec l'interposition d'une garniture toroïdale d'étanchéité 39. Comme on le comprendra, ces systèmes de connexion supposent que le distributeur 2 soit formé en matière plastique, ce qui est rendu possible par l'adoption des principes de l'invention. Le collecteur 4 est destiné à être montré sur le collecteur d'aspiration (non représenté) d'un moteur à carburation, et au-dessus du couvercle 5 est destiné à être monté un filtre d'air d'aspiration ; pour fixer la boîte de ce dernier, le couvercle 5 présente des tiges filetées 25 ; le filtre d'air n'est pas représenté.The structure of the carburetor shown mainly comprises a body 1, a distributor 2 arranged below the body 1, a manifold 4 and a cover 5. The latter is applied to the body 1 by means of screws not shown, with the interposition of 'A flat seal 27; the distributor 2 is fixed to the body 1 by teeth with elastic trigger 36 and with the interposition of a toroidal sealing gasket 37; the manifold 4 is fixed to the distributor 2 by means of teeth with elastic release 38 and with the interposition of a toroidal sealing gasket 39. As will be understood, these connection systems assume that the distributor 2 is formed of plastic material , which is made possible by the adoption of the principles of the invention. The manifold 4 is intended to be shown on the suction manifold (not shown) of a carburetion engine, and above the cover 5 is intended to be mounted a suction air filter; to fix the latter's box, the cover 5 has threaded rods 25; the air filter is not shown.

Le corps 1 est traversé par une pluralité de diffuseurs 6, dans ce cas en nombre de sept, distribués sur une circonférence et formant deux groupes, respectivement de quatre et de trois diffuseurs. Aux diffuseurs 6 du corps 1 correspondent, dans le couvercle 5 et dans le distributeur 2, des trous, respectivement 40 et 41, qui prolongent le profil des diffuseurs 6. Dans chaque diffuseur 6 et précisément près de sa section restreinte, débouche un petit tube 12 opportunément courbé, à l'extrémité opposée duquel est appliqué un gicleur 11. Les divers gicleurs 11 des deux groupes de diffuseurs s'enfoncent dans des cuves respectives 35 et 34 qui, à travers des conduits 33 et 32, communiquent avec une cuve centrale à niveau constant 30. Cette cuve est alimentée par la pompe d'alimentation habituelle (non représentée) à travers un raccord 13, un filtre d'essence 15 et un gicleur doseur de débit 16. Le niveau constant est assuré par un déversoir 7, et le carburant alimenté en excès se verse dans une cuve arquée 31, d'où il passe à un raccord 14 destiné à être relié à une pompe de récupération (non représentée), qui renvoie au réservoir le carburant non utilisé. Grâce aux communications 32 et 33, le même niveau constant de la cuve 30 s'établit aussi dans les cuves 34 et 35 et submerge, avec une charge préétablie, les gicleurs 11 des tubes 12.The body 1 is traversed by a plurality of diffusers 6, in this case in number of seven, distributed over a circumference and forming two groups, respectively of four and three diffusers. To the diffusers 6 of the body 1 correspond, in the cover 5 and in the distributor 2, holes, respectively 40 and 41, which extend the profile of the diffusers 6. In each diffuser 6 and precisely near its restricted section, a small tube opens. 12 suitably curved, at the opposite end of which a nozzle is applied 11. The various nozzles 11 of the two groups of diffusers sink into respective tanks 35 and 34 which, through conduits 33 and 32, communicate with a central tank at constant level 30. This tank is supplied by the usual supply pump (not shown) through a connector 13, a fuel filter 15 and a flow metering nozzle 16. The constant level is ensured by a weir 7, and the fuel supplied in excess is poured into an arcuate tank 31, from which it passes to a connector 14 intended to be connected to a recovery pump (not shown), which returns the unused fuel to the tank. Thanks to communications 32 and 33, the same constant level of the tank 30 is also established in the tanks 34 and 35 and submerges, with a preset load, the nozzles 11 of the tubes 12.

Entre le corps 1 et le distributeur 2 est disposé un obturateur tournant formé par un disque 3 muni de deux fentes arquées 18 et 19. Ces fentes sont disposées de manière que, dans une position du disque 3 (complète ouverture), elles laissent libres tous les diffuseurs 6 des deux groupes, dans une autre position (fermeture totale) elles ferment tous les diffuseurs, et, en passant de cette dernière position à la première, elles découvrent d'abord graduellement le premier diffuseur 6' (appartenant au premier groupe) et_puis, après avoir complètement ouvert ce premier diffuseur, elles découvrent le second diffuseur 6" (appartenant au second groupe), ensuite le troisième diffuseur 6"' (appartenant de nouveau au premier groupe) et ainsi de suite. Pratiquement, comme on peut l'observer sur la figure 4, il est préférable de prévoir un certain degré de superposition des ouvertures, c'est-à-dire, commencer à découvrir chaque diffuseur légèrement avant d'avoir atteint l'ouverture complète du diffuseur précédent, afin d'obtenir une meilleure gradualité de l'ouverture totale. En outre, la position de complète fermeture peut ne pas être réellement atteinte, puisque habituellement une certaine ouverture de l'obturateur est nécessaire aussi pour le fonctionnement au minimum. Pour faire comprendre mieux ce procédé d'ouverture graduelle, les références de 6' à 6v" qui concernent les diffuseurs ont été placées aussi dans la figure 4, en correspondance des trous respectifs 41 du distributeur.Between the body 1 and the distributor 2 is disposed a rotary shutter formed by a disc 3 provided with two arcuate slots 18 and 19. These slots are arranged so that, in a position of the disc 3 (full opening), they leave all free the diffusers 6 of the two groups, in another position (total closure) they close all the diffusers, and, passing from this last position to the first, they first gradually discover the first diffuser 6 '(belonging to the first group) and_then, after having completely opened this first diffuser, they discover the second 6 "diffuser (belonging to the second group), then the third 6"'diffuser (belonging again to the first group) and so on. In practice, as can be seen in FIG. 4, it is preferable to provide a certain degree of superposition of the openings, that is to say, start to discover each diffuser slightly before having reached the complete opening of the previous diffuser, in order to obtain a better graduality of the total opening. In addition, the fully closed position may not be really reached, since usually a certain opening of the shutter is also necessary for operation to a minimum. To better understand this gradual opening process, the references from 6 'to 6 v "which relate to the diffusers have also been placed in FIG. 4, in correspondence with the respective holes 41 of the dispenser.

On comprend donc que, dans n'importe quelle condition de fonctionnement, on a toujours un certain nombre de diffuseurs 6 complètement libres et substantiellement un seul diffuseur par- tialisé par l'obturateur, de sorte que la plus grande partie du carburant est introduite dans le flux d'air aspiré dans des diffuseurs qui fonctionnent dans les meilleures conditions. Grâce au nombre relativement élevé de diffuseurs, le carburateur fonctionne à dépression presque constante et, même dans le fonctionnement à basses charges, dans les diffuseurs (qui peuvent avoir une section relativement petite) la vitesse de t'air se maintient élevée, en assurant ainsi un mélange correct et uniforme.It is therefore understood that, in any operating condition, there is always a certain number of diffusers 6 completely free and substantially a single diffuser parted by the shutter, so that most of the fuel is introduced into the air flow sucked into diffusers which work under the best conditions. Thanks to the relatively high number of diffusers, the carburetor operates at almost constant vacuum and, even in operation at low loads, in diffusers (which may have a relatively small section) the air speed is kept high, thus ensuring a correct and uniform mixture.

Il est en outre évident que, quoique les diffuseurs 6 soient illustrés comme tous égaux, ils peuvent avoir des sections différentes ou/et ils peuvent être servis par des gicleurs 11 de différent calibre, de manière à obtenir le meilleur dosage pour chaque régime de fonctionnement. En outre, même si les fentes 18 et 19 de l'obturateur 3'ont été illustrées comme ayant une largeur uniforme, elles peuvent avoir tout autre profil pour obtenir une loi désirée de variation de la section totale de passage en fonction de la commande de l'accélérateur, cette loi pouvant être approximativement linéaire, exponentielle ou autre, pour obtenir la meilleure manoeuvrabilité du moteur.It is also obvious that, although the diffusers 6 are illustrated as all equal, they may have different sections or / and they may be served by nozzles 11 of different caliber, so as to obtain the best dosage for each operating regime . In addition, even if the slots 18 and 19 of the shutter 3 ′ have been illustrated as having a uniform width, they may have any other profile in order to obtain a desired law of variation of the total passage section according to the control of the accelerator, this law can be approximately linear, exponential or other, to obtain the best maneuverability of the engine.

L'obturateur tournant 3 est commandé au . moyen d'un arbre 20, qui passe à travers le corps 1 et le couvercle 5 et qui, au-dessus de ce dernier, est relié à un levier 21 rappelé vers la position de minimum par un ressort 23 appuyé à un relief 42 du couvercle 5. Au levier 21 on accrochera le bowden ou autre transmission de commande de l'accélération, non représenté, agissant substantiellement selon la ligne à points et traits 43 de la figure 1. Une garniture toroïdale 22 établit l'étanchéité entre le petit arbre 20 et le corps 1.The rotary shutter 3 is controlled by. by means of a shaft 20, which passes through the body 1 and the cover 5 and which, above the latter, is connected to a lever 21 returned to the minimum position by a spring 23 supported on a relief 42 of the cover 5. To the lever 21 will be hooked the bowden or other acceleration control transmission, not shown, acting substantially along the line with dots and lines 43 of FIG. 1. A toroidal seal 22 establishes the seal between the small shaft 20 and body 1.

Le fonctionnement au régime de minimum, dans un carburateur selon l'invention, peut être rendu correct en prévoyant un premier diffuseur particulièrement projeté pour ce fonctionnement, et dans ce cas aucun dispositif spécial ne doit être prévu à cet effet. Toutefois, quand on le préfère, on peut adopter un dispositif spécial de minimum comme celui qui est représenté dans les figures 1 et 7. Dans ce cas, on dérive d'une des cuves d'alimentation du carburant (dans l'exemple, la cuve 34) un conduit 10 qui porte le carburant à un passage d'air 9 prévu à cet effet à travers le corps 1, le distributeur 2 et le couvercle 5. Le conduit 10 peut être plus ou moins étranglé au moyen d'une vis à pointeau 26, et le passage d'air 9 peut être lui aussi plus ou moins étranglé au moyen d'une vis de réglage 17. Le fonctionnement au régime de minimum peut être donc opportunément réglé au moyen des vis 17 et 26. Le passage 9 peut être ouvert en permanence, puisque sa section résulte négligeable pour le fonctionnement aux régimes plus hauts, ou bien il peut être opportunément occlus par l'obturateur tournant 3, à partir d'un régime d'alimentation déterminé.Operation at minimum regime, in a carburetor according to the invention, can be made correct by providing a first diffuser particularly designed for this operation, and in this case no special device should be provided for this purpose. However, when preferred, a special minimum device such as that shown in Figures 1 and 7 can be adopted. In this case, one is derived from one of the fuel supply tanks (in the example, the tank 34) a conduit 10 which carries the fuel to an air passage 9 provided for this purpose through the body 1, the distributor 2 and the cover 5. The conduit 10 can be more or less throttled by means of a screw needle 26, and the air passage 9 can also be more or less throttled by means of an adjusting screw 17. The operation at minimum speed can therefore be conveniently adjusted by means of the screws 17 and 26. The passage 9 can be opened permanently, since its cross section is negligible for operation at higher speeds, or it can be conveniently occluded by the rotary shutter 3, from a determined supply speed.

Bien que la possibilité de graduer à volonté l'ouverture des diffuseurs et les dosages respectifs, donnée par l'invention, minimise l'utilité d'une pompe de reprise, dans les cas où celle-ci est demandée elle peut être facilement installée dans une des zones du corps 1 non occupées par les diffuseurs.Although the possibility of graduating at will the opening of the diffusers and the respective dosages, given by the invention, minimizes the usefulness of a recovery pump, in cases where this is required it can be easily installed in one of the areas of the body 1 not occupied by the diffusers.

Comme le montrent les figures 5 et 6, la pompe de reprise comprend un piston 28 introduit, sans étanchéité, dans un cylindre 8 formé dans le corps 1, adjacent et en communication, au-dessus d'une paroi 44, avec la cuve centrale 30 à niveau constant. Du cylindre 8 se départ un conduit 45 qui, à travers un clapet de non-retour 29, débouche dans le premier diffuseur 6. Le piston 28 est poussé vers le haut par un ressort 46 et il est relié à une tige 47 qui forme poussoir contre une came frontale 48 présentée inférieurement par le levier 21 de commande de l'obturateur tournant. Donc, quand on fait tourner l'obturateur dans le sens d'augmenter l'ouverture des diffuseurs, la tige 47 avec le piston 28 est baissée. Puisque le piston ne fait pas étanchéité, si la manoeuvre est lente il ne se produit aucun refoulement, mais si la manoeuvre est rapide, du carburant est poussé dans le conduit 45 et se verse dans le premier diffuseur 6, en fournissant ainsi l'alimentation plus forte demandée par l'accélération rapide.As shown in Figures 5 and 6, the recovery pump comprises a piston 28 inserted, without sealing, in a cylinder 8 formed in the body 1, adjacent and in communication, above a wall 44, with the central tank 30 at constant level. From the cylinder 8 starts a conduit 45 which, through a non-return valve 29, opens into the first diffuser 6. The piston 28 is pushed upwards by a spring 46 and it is connected to a rod 47 which forms a pusher against a front cam 48 presented below by the lever 21 for controlling the rotary shutter. Therefore, when the shutter is rotated in the direction of increasing the opening of the diffusers, the rod 47 with the piston 28 is lowered. Since the piston does not seal, if the maneuver is slow there is no backflow, but if the maneuver is rapid, fuel is pushed into the duct 45 and is poured into the first diffuser 6, thus providing the supply stronger demanded by rapid acceleration.

Le dispositif pour le départ à froid (starter), quand on le demande, peut être simplement constitué par un élément plat 24 pivoté sur l'arbre 20 et coulissant sur le couvercle 5 sous la commande d'un tirant, non représenté, disposé selon la ligne à points et traits 50 de la figure 1. Le mouvement de l'élément 24 est limité, par des arrêts 49 formés par le couvercle 5, entre deux positions, dans une desquelles (marche normale) l'élément 24 n'interfère pas avec les diffuseurs 6, tandis que dans l'autre position (départ à froid) l'élément 24 ferme partiellement le premier diffu- seu r 6.The device for the cold start (choke), when requested, can be simply constituted by a flat element 24 pivoted on the shaft 20 and sliding on the cover 5 under the control of a tie rod, not shown, arranged according to the line with dots and lines 50 of FIG. 1. The movement of the element 24 is limited, by stops 49 formed by the cover 5, between two positions, in one of which (normal operation) the element 24 does not interfere not with the diffusers 6, while in the other position (cold start) the element 24 partially closes the first diffuser 6.

Dans la forme de réalisation représentée, le couvercle 5 est prédisposé pour recevoir sur lui le corps d'un filtre d'air. Mais il est aussi possible de conformer le couvercle 5 de manière qu'il forme lui-même le siège pour l'application d'une cartouche filtrante pour l'air aspiré, en évitant ainsi de pourvoir le carburateur d'un corps spécial pour le filtre et en simplifiant les opérations de montage.In the embodiment shown, the cover 5 is predisposed to receive thereon the body of an air filter. But it is also possible to shape the cover 5 so that it itself forms the seat for the application of a filter cartridge for the aspirated air, thus avoiding providing the carburetor with a special body for the filter and simplifying assembly operations.

L'application de la présente invention autorise l'adoption de formes particulièrement appropriées à une fabrication en matière synthétique moulée, mais quand on le demande les pièces du carburateur selon l'invention peuvent être produites avec un autre matériel, tel que le zamak (alliage de zinc et aluminium) ou un alliage léger, par moulage sous pression.The application of the present invention allows the adoption of forms particularly suitable for manufacturing in molded synthetic material, but when requested the parts of the carburetor according to the invention can be produced with another material, such as zamak (alloy zinc and aluminum) or a light alloy, by die-casting.

Bien qu'une cuve à niveau constant maintenu au moyen d'un déversoir soit particulièrement appropriée pour des raisons constructives, évidemment le carburateur peut être pourvu de n'importe quel autre genre de cuve à niveau constant, par exemple à flotteur.Although a constant level tank maintained by means of a weir is particularly suitable for constructive reasons, obviously the carburetor can be provided with any other kind of constant level tank, for example with float.

Le nombre des diffuseurs, qui dans l'exemple est de sept, peut naturellement varier d'un minimum de trois à un maximum déterminé par les dimensions d'encombrement admises pour le carburateur. La distance angulaire entre diffuseurs successifs, peut être choisie différemment, et elle peut être uniforme ou bien différente pour les divers diffuseurs.The number of diffusers, which in the example is seven, can naturally vary from a minimum of three to a maximum determined by the overall dimensions accepted for the carburetor. The angular distance between successive diffusers can be chosen differently, and it can be uniform or even different for the various diffusers.

Claims (8)

1. A carburetor for Otto engines, of the type in which the fuel is maintained at a constant level within a chamber (30) and is introduced into the flow of air sucked by the motor in consequence of the depression generated by the flow in the nozzle throat area of a Venturi diffuser (6), and comprising more than two diffusers (6) situated within a body (1) of the carburetor, each diffuser (6) comprising a pipe (12) with a jet (11) for the fuel, said pipe opening into the diffuser (6), said diffusers cooperating with a shutter (3) formed by a flat disk whose active surface moves in a direction perpendicular to the axis of said diffusers (6) and is provided with passage openings (18, 19) formed in such a manner as to sequentially uncover said diffusers (6) according to a predetermined law by being made to rotate about a central axis by means of central control shaft (20), characterized in that the various diffusers (6) are disposed, with their axes parallel to each other, in two groups along two circle arcs opposite the one another with respect to the center, and that the shutter (3) is disposed between said body (1) and a distributor (2) positioned upstream a collector (4), said shutter (3) being provided with two arcuate and opposite passage openings (18, 19) disposed in such a manner as to alternately uncover a diffuser (6) disposed on one of the arcs and a diffuser (6) disposed on the opposite arc, and that the constant level chamber (30) is disposed in the central region of said body (1) of the carburetor and is connected to two arcuate chambers (34, 35) extending parallel to the arcs along which the diffusers (6) are disposed with their pipes (12) whose other ends impinge into said chambers (34, 35).
2. A carburetor according to Claim 1, characterized in that said constant level chamber (30) is of the type with a spillway (7).
3. A carburetor according to Claim 1 or 2, characterized in that the portions of the body (1) of the carburetor which are not occupied by the diffusers (6) accommodate a jet (9) for the idling speed of the engine and an accelerator pump (8).
4. A carburetor according to one of the Claims 1 to 3, characterized in that said control shaft (20) passes through the body and through a cover and carries, above the cover, a control lever (21) provided with a return spring (23) and connected to a control means (43) such as a bowden.
5. A carburetor according to Claim 4, characterized in that said control lever (21) has at its lower side a cam (48) by means of which it cooperates with the rod (47) of the piston (28) of an accelerator pump (8) mounted within the body (1) of the carburetor.
6. A carburetor according to one of the Claims 1 to 5, characterized in that each diffuser (6) and the respective jet (11) are individually dimensioned.
7. A carburetor according to Claim 6, characterized in that the arrangement of the various diffusers (6) and the configuration of the passage openings (18, 19) of the shutter (3) are chosen, relative to one another, in such a manner as to give rise to the beginning of the opening of each diffuser (6) with a certain advance relative to the termination of the opening of the preceding diffuser (6).
8. A carburetor according to any one of the Claims 1 to 7, characterized in that the structural parts (1, 2, 4) of the carburetor are made of molded plastics.
EP82200759A 1981-07-02 1982-06-18 Carburettor for internal-combustion engines Expired EP0069416B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT67919/81A IT1144263B (en) 1981-07-02 1981-07-02 CARBURETOR FOR INTERNAL COMBUSTION ENGINES
IT6791981 1981-07-02

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EP0069416A2 EP0069416A2 (en) 1983-01-12
EP0069416A3 EP0069416A3 (en) 1984-03-07
EP0069416B1 true EP0069416B1 (en) 1986-10-01

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EP (1) EP0069416B1 (en)
DE (1) DE3273547D1 (en)
IT (1) IT1144263B (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1224458B (en) * 1988-09-30 1990-10-04 Marco Morini CORRECT SPRAYER FOR THE CARBURETOR OF A CARBURETOR ENGINE

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US948612A (en) * 1908-04-06 1910-02-08 Krause Carbureter Company Carbureter for combustion-engines.
FR437972A (en) * 1911-12-21 1912-05-04 Pierre Velter Rational carburetion device for gas, petroleum or petrol combustion engines
US1180976A (en) * 1915-07-07 1916-04-25 John Leslie Cloudsley Carbureter.
US1205602A (en) * 1916-01-11 1916-11-21 Thomas John Disturnal Carbureter.
FR488209A (en) * 1916-02-23 1918-09-14 Leonard Longley Improvements to carburettors for internal combustion engines
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FR580262A (en) * 1924-04-17 1924-11-04 Carburetor
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Also Published As

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IT8167919A0 (en) 1981-07-02
EP0069416A2 (en) 1983-01-12
EP0069416A3 (en) 1984-03-07
DE3273547D1 (en) 1986-11-06
IT1144263B (en) 1986-10-29
US4465641A (en) 1984-08-14

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