EP0088678B1 - Pneumatic control device for a carburettor air throttle of an internal combustion engine - Google Patents

Pneumatic control device for a carburettor air throttle of an internal combustion engine Download PDF

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Publication number
EP0088678B1
EP0088678B1 EP19830400411 EP83400411A EP0088678B1 EP 0088678 B1 EP0088678 B1 EP 0088678B1 EP 19830400411 EP19830400411 EP 19830400411 EP 83400411 A EP83400411 A EP 83400411A EP 0088678 B1 EP0088678 B1 EP 0088678B1
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EP
European Patent Office
Prior art keywords
capsule
chamber
intake manifold
subjected
depression
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Expired
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EP19830400411
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German (de)
French (fr)
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EP0088678A1 (en
Inventor
Jean-Jacques Schmit
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Regie Nationale des Usines Renault
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Regie Nationale des Usines Renault
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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
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/02—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling being chokes for enriching fuel-air mixture
    • 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
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/08—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically
    • F02M1/14—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically dependent on pressure in combustion-air- or fuel-air-mixture intake

Definitions

  • the present invention relates to carburetors for internal combustion engines, of the type in which, during the cold operation of the engine, the tilting of an air flap is controlled as a function of the engine load between a minimum open position corresponding to the full load engine speed and a maximum opening position corresponding to a low load engine speed, and it relates more particularly to a pneumatic device for controlling such an air flap.
  • Document EP-A-0 059 654 (publication date 8.9.82, priority 3.3.81) describes a carburetor of this type in which the control of the air flap is ensured by a vacuum capsule comprising a membrane connected to the flap of air by a linkage and subjected on one side to atmospheric pressure and on the other to the vacuum prevailing at the intake manifold as well as to the thrust of a spring biasing the membrane in the direction which tends to close the air shutter.
  • a cam controlled manually by the "starter” puller includes a movable stop between an active position where, in a first position of the cam corresponding to cold start, it cooperates with the linkage to limit the stroke at the opening of the air shutter and defines a half-open position of the latter, and a retracted position where, in a second position of the cam corresponding to cold operation, it allows the shutter to switch between its minimum open positions and maximum opening.
  • the capsule In the second position of the cam and when the engine is running at idle, vehicle stopped, the capsule, under the influence of vacuum (approximately 600 g / cm 2 ) then prevailing at the intake manifold, pulls the linkage and opens the air shutter.
  • vacuum approximately 600 g / cm 2
  • the vacuum in the intake manifold decreases and, depending on the degree of acceleration, it can reach values between 600 and 0 g / cm 2 .
  • the spring of the capsule pushes the membrane and the return spring of the air flap ensures the closing of the latter.
  • the fuel mixture is then enriched, which makes it possible to obtain the desired acceleration of the vehicle.
  • the shutter To obtain good light acceleration of the vehicle, that is to say with a very low drop in depression, the shutter must begin to close as soon as the decrease in depression is equal to 100 g / cm 2 relative to the depression prevailing in the intake manifold when the engine is idling, vehicle stopped. However, for certain stabilized vehicle speeds, the reduction in vacuum in the intake manifold is greater than 100 g / cm 2 and, consequently, the shutter is not completely open. The fuel mixture introduced into the engine is then richer, and the consumption higher.
  • the present invention aims to eliminate this drawback, which can also be encountered in other carburetors of the aforementioned type. To this end, it relates to a pneumatic control device for the air flap of a carburetor for an internal combustion engine, a carburetor of the type described in document FR-A-2 393 161 and in which, during operation at when the engine is cold, the tilting of the air flap is controlled as a function of the engine load between a minimum opening position corresponding to the engine's full load speed and a maximum opening position corresponding to a low load engine speed.
  • said control device comprising a capsule having two chambers separated by a motor element connected by a linkage to the air flap and subjected to the action of a return spring biasing the motor element in the direction which tends to close the air shutter, one of the chambers being subjected to atmospheric pressure and the other to the vacuum of the intake manifold.
  • said other chamber has an orifice for setting the controlled atmosphere and the control device comprises a second capsule with differential operation which opens the orifice in response to slight variations in the vacuum in the manifold of admission.
  • the second capsule comprises a motor element integral with a rod carrying at its free end a plug controlling the closing of the orifice for setting the controlled atmosphere, and the motor element of the second capsule defines a first chamber subjected directly to the depression of the intake manifold by a conduit and a second chamber subjected to the depression of the intake manifold by another conduit in which is calibrated, a return spring urging the motor element in the direction which tends to close the air vent.
  • Figure 1 schematically illustrates the starting flap mechanism of a carburetor which has been shown in fine lines the outline of the body 1, assumed transparent for clarity of the drawing.
  • the body 1 comprises a venturi 2 in which is mounted a fuel spray device 3.
  • a throttle valve 4 is rotatably mounted about an eccentric axis 5 between a fully closed position delimited by a stop 6 and a fully open position.
  • the rotation of the butterfly 4 is controlled by a lever 7 to which is hooked a spring 8 urging the butterfly 4 to its closed position.
  • An air flap 9 for the cold start is also rotatably mounted around an eccentric axis 10 in the body 1, upstream of the venturi 2. This flap can switch between a completely closed position delimited by a stop 11 and a fully open position.
  • the axis 10 is integral with one end of a lever 12 which controls the movements of the air flap 9 between its open and closed positions.
  • a spring 13 hooked to the lever 12 biases the flap 9 towards its closed position.
  • a cam 25 is articulated around an axis 26 parallel to the axes 5 and 10. The rotational movements of the cam 25 around its axis 26 are controlled by a lever 27 integral with the axis 26 and a rod 28 with manual actuation .
  • a part of the outer contour of the cam 25 constitutes a first cam surface D with which the free end of the lever 7 cooperates to half-open the butterfly valve 4 when the choke is fully pulled.
  • the cam 25 has a hook-shaped appendage 30 whose internal contour constitutes a cam surface F extending another cam surface E.
  • This surface E is defined by a second part of the external contour of the cam 25 and cooperates with the articulation 23 of the lever 12 with the rod 14 to define the minimum open position of the air shutter when the choke is partially pushed back, and keep this shutter fully open when the choke is fully pushed back.
  • the vacuum in the intake manifold is applied to the control device 16 and the articulation 23 is applied against the cam surface F.
  • the flap 9 then takes a half-open position as shown in FIG. 1.
  • the appendix 30, which acts as a stop, is retracted by the rotation of the cam 25, as shown in FIG. 2: in fact, in this position of the cam 25, the lever 12 is free to switch between the fully open position of the shutter of FIG. 2 and a minimum open position defined by the abutment of the joint 23 against the cam surface E.
  • the position of the starting flap 9, and therefore the enrichment of the mixture then depend on the operating conditions of the engine.
  • the vacuum in the intake manifold is high because the opening of the throttle valve is small, and the air flap 9 is fully open.
  • the engine although cold, operates with an unenriched mixture identical to that supplied to it hot.
  • the throttle valve is wide open, the vacuum at the intake manifold decreases rapidly and the spring 13, suitably sized, immediately returns the flap 9 to its position opening imposed by ramp E.
  • FIG. 3 shows the pneumatic control device 16 making it possible to ensure full opening of the air flap 9, even when the vacuum in the intake manifold is low, while ensuring the closing of this flap 9 for a very small variation of this depression at the start of acceleration.
  • This device comprises two pneumatic capsules 101 and 102 rigidly connected to each other by parts 103 and 104.
  • the rod 14 is integral with a membrane 106 of the first capsule 101, of which the left chamber 101 A, relative to the membrane 106, is subjected to atmospheric pressure.
  • the straight chamber 101 B of the capsule 101 comprises a spring 107, having a calibration allowing the displacement of the membrane 106 under a very low vacuum in the intake manifold (not shown). This movement ensures the complete opening of the flap 9, via the rod 14.
  • the chamber 101 B of the capsule 101 where the spring 107 is located is subjected to the vacuum prevailing in the intake manifold by a conduit 108 in which there is a calibration 109 and it includes an orifice 101 C for setting the controlled atmosphere.
  • the sealing of the chamber 101 B with respect to the atmosphere is carried out using a plug 110 closing the orifice 101 C and secured to a rod 111 of the capsule 102.
  • This rod is attached to the membrane 112 of the capsule 102.
  • the capsule 102 comprises two chambers 102 A and 102 B which are separated by the membrane 112.
  • the chamber 102 A is subjected to the vacuum prevailing in the intake manifold via a conduit 113
  • the seal with respect to the atmosphere of the chamber 102 A of the capsule 102 is ensured by a bellows 117 which is tightened on one side on the rod 111, and on the other, on the left shell 105 of the capsule 102.
  • the straight chamber 102 B of the capsule 102 comprises a spring 114, which has a very low calibration so that a low depression of approximately 50 g / cm 2 can move the membrane 112, and consequently the plug 110, to bring the chamber 101 A of the capsule 101 to atmospheric pressure.
  • the right chamber 102 B of the capsule 102 is subjected to the vacuum prevailing at the intake manifold via a conduit 115, in which a calibration 116 is placed.
  • the vacuum in the intake manifold is strong.
  • This vacuum applied via the conduit 108 and the calibration 109 in the right chamber 101 B of the capsule 101 acts on the membrane 106, which compresses the spring 107.
  • the membrane 106 moves the rod 14 and the starting flap 9 is open.
  • the two chambers of the capsule 102 are subjected to the vacuum in the intake manifold, but the establishment of this vacuum in the right-hand part takes place with a delay because of the calibration 116.
  • the depression balance in the two chambers of the capsule 102 is broken: the depression immediately decreases in the left chamber 102 A of the capsule 102, but on the other hand, this reduction in depression in the straight chamber 102 B of the capsule 102 is delayed by the calibration 116.
  • the spring 114 repels the membrane 112 which moves the rod 111 with its plug 110, which closes the orifice of the venting the right chamber 101 B of the capsule 101.
  • a depression is restored in the right chamber 101 B of the capsule 101.
  • This depression attracts the membrane 106 which compresses the spring 107, and the rod 14 opens the shutter 9 in a position which depends on the balance established between this depression, itself a function of the position of the butterfly 4, and of the opposing force of the springs 13 and 107.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Means For Warming Up And Starting Carburetors (AREA)
  • Control Of Throttle Valves Provided In The Intake System Or In The Exhaust System (AREA)

Description

La présente invention concerne les carburateurs pour moteurs à combustion interne, du type dans lequel, pendant le fonctionnement à froid du moteur, le basculement d'un volet d'air est commandé en fonction de la charge du moteur entre une position d'ouverture minimale correspondant au régime de pleine charge du moteur et une position d'ouverture maximale correspondant à un régime de faible charge du moteur, et elle se rapporte plus particulièrement à un dispositif pneumatique de commande d'un tel volet d'air.The present invention relates to carburetors for internal combustion engines, of the type in which, during the cold operation of the engine, the tilting of an air flap is controlled as a function of the engine load between a minimum open position corresponding to the full load engine speed and a maximum opening position corresponding to a low load engine speed, and it relates more particularly to a pneumatic device for controlling such an air flap.

Le document EP-A-0 059 654 (date de publication 8.9.82, priorité 3.3.81) décrit un carburateur de ce type dans lequel la commande du volet d'air est assurée par une capsule à dépression comportant une membrane reliée au volet d'air par une tringlerie et soumise d'un côté à la pression atmosphérique et de l'autre à la dépression régnant au collecteur d'admission ainsi qu'à la poussée d'un ressort sollicitant la membrane dans le sens qui tend à fermer le volet d'air. En outre, une came commandée manuellement par la tirette de « starter comporte une butée mobile entre une position active où, dans une première position de la came correspondant au démarrage à froid, elle coopère avec la tringlerie pour limiter la course à l'ouverture du volet d'air et définit une position d'entrebâillement de ce dernier, et une position escamotée où, dans une seconde position de la came correspondant au fonctionnement à froid, elle autorise le basculement du volet entre ses positions d'ouverture minimale et d'ouverture maximale.Document EP-A-0 059 654 (publication date 8.9.82, priority 3.3.81) describes a carburetor of this type in which the control of the air flap is ensured by a vacuum capsule comprising a membrane connected to the flap of air by a linkage and subjected on one side to atmospheric pressure and on the other to the vacuum prevailing at the intake manifold as well as to the thrust of a spring biasing the membrane in the direction which tends to close the air shutter. In addition, a cam controlled manually by the "starter" puller includes a movable stop between an active position where, in a first position of the cam corresponding to cold start, it cooperates with the linkage to limit the stroke at the opening of the air shutter and defines a half-open position of the latter, and a retracted position where, in a second position of the cam corresponding to cold operation, it allows the shutter to switch between its minimum open positions and maximum opening.

Dans la deuxième position de la came et lorsque le moteur fonctionne au ralenti, véhicule arrêté, la capsule, sous l'influence de la dépression (environ 600 g/cm2) régnant alors au collecteur d'admission, tire la tringlerie et ouvre le volet d'air. Par contre, lors d'une accélération, la dépression dans le collecteur d'admission diminue et, suivant le degré de l'accélération, elle peut atteindre des valeurs comprises entre 600 et 0 g/cm2. Dans ce cas le ressort de la capsule repousse la membrane et le ressort de rappel du volet d'air assure la fermeture de ce dernier. Le mélange combustible est alors enrichi, ce qui permet d'obtenir l'accélération voulue du véhicule.In the second position of the cam and when the engine is running at idle, vehicle stopped, the capsule, under the influence of vacuum (approximately 600 g / cm 2 ) then prevailing at the intake manifold, pulls the linkage and opens the air shutter. On the other hand, during an acceleration, the vacuum in the intake manifold decreases and, depending on the degree of acceleration, it can reach values between 600 and 0 g / cm 2 . In this case the spring of the capsule pushes the membrane and the return spring of the air flap ensures the closing of the latter. The fuel mixture is then enriched, which makes it possible to obtain the desired acceleration of the vehicle.

Pour obtenir une bonne accélération légère du véhicule, c'est-à-dire avec une très faible baisse de dépression, le volet doit commencer à se fermer dès que la diminution de dépression est égale à 100 g/cm2 par rapport à la dépression régnant dans le collecteur d'admission lors de marche à vide du moteur, véhicule arrêté. Or, pour certaines vitesses stabilisées du véhicule, la diminution de dépression dans le collecteur d'admission est supérieure à 100 g/cm2 et, en conséquence, le volet n'est pas complètement ouvert. Le mélange combustible introduit dans le moteur est alors plus riche, et la consommation plus élevée.To obtain good light acceleration of the vehicle, that is to say with a very low drop in depression, the shutter must begin to close as soon as the decrease in depression is equal to 100 g / cm 2 relative to the depression prevailing in the intake manifold when the engine is idling, vehicle stopped. However, for certain stabilized vehicle speeds, the reduction in vacuum in the intake manifold is greater than 100 g / cm 2 and, consequently, the shutter is not completely open. The fuel mixture introduced into the engine is then richer, and the consumption higher.

La présente invention a pour but d'éliminer cet inconvénient, que l'on peut rencontrer également dans d'autres carburateurs du type précité. A cet effet, elle a pour objet un dispositif de commande pneumatique du volet d'air d'un carburateur pour moteur à combustion interne, carburateur du type décrit dans le document FR-A-2 393 161 et dans lequel, pendant le fonctionnement à froid du moteur, le basculement du volet d'air est commandé en fonction de la charge du moteur entre une position d'ouverture minimale correspondant au régime de pleine charge du moteur et une position d'ouverture maximale correspondant à un régime de faible charge du moteur, ledit dispositif de commande comprenant une capsule présentant deux chambres séparées par un élément moteur relié par une tringlerie au volet d'air et soumis à l'action d'un ressort de rappel sollicitant l'élément moteur dans le sens qui tend à fermer le volet d'air, l'une des chambres étant soumise à la pression atmosphérique et l'autre à la dépression du collecteur d'admission. Suivant une particularité de l'invention, ladite autre chambre présente un orifice de mise à l'atmosphère contrôlée et le dispositif de commande comprend une seconde capsule à fonctionnement différentiel qui ouvre l'orifice en réponse à de faibles variations de la dépression dans le collecteur d'admission.The present invention aims to eliminate this drawback, which can also be encountered in other carburetors of the aforementioned type. To this end, it relates to a pneumatic control device for the air flap of a carburetor for an internal combustion engine, a carburetor of the type described in document FR-A-2 393 161 and in which, during operation at when the engine is cold, the tilting of the air flap is controlled as a function of the engine load between a minimum opening position corresponding to the engine's full load speed and a maximum opening position corresponding to a low load engine speed. motor, said control device comprising a capsule having two chambers separated by a motor element connected by a linkage to the air flap and subjected to the action of a return spring biasing the motor element in the direction which tends to close the air shutter, one of the chambers being subjected to atmospheric pressure and the other to the vacuum of the intake manifold. According to a feature of the invention, said other chamber has an orifice for setting the controlled atmosphere and the control device comprises a second capsule with differential operation which opens the orifice in response to slight variations in the vacuum in the manifold of admission.

La seconde capsule comporte un élément moteur solidaire d'une tige portant à son extrémité libre un bouchon commandant l'obturation de l'orifice de mise à l'atmosphère contrôlée, et l'élément moteur de la seconde capsule délimite une première chambre soumise directement à la dépression du collecteur d'admission par un conduit et une deuxième chambre soumise à la dépression du collecteur d'admission par un autre conduit dans lequel est disposé un calibrage, un ressort de rappel sollicitant l'élément moteur dans le sens qui tend à fermer l'orifice de mise à l'atmosphère contrôlée.The second capsule comprises a motor element integral with a rod carrying at its free end a plug controlling the closing of the orifice for setting the controlled atmosphere, and the motor element of the second capsule defines a first chamber subjected directly to the depression of the intake manifold by a conduit and a second chamber subjected to the depression of the intake manifold by another conduit in which is calibrated, a return spring urging the motor element in the direction which tends to close the air vent.

D'autres caractéristiques et avantages de l'invention ressortiront de la description qui va suivre d'un exemple de sa réalisation illustré par les dessins annexés sur lesquels :

  • la figure 1 est une vue schématique d'un mécanisme à volet de départ auquel peut être appliqué le dispositif de commande pneumatique suivant l'invention, représenté dans la position « starter tiré à fond », immédiatement après le démarrage du moteur ;
  • la figure 2 est une vue du mécanisme de la figure 1, représenté dans la position partiellement repoussée du starter ; et
  • la figure 3 est une vue en coupe longitudinale du dispositif de commande pneumatique suivant l'invention.
Other characteristics and advantages of the invention will emerge from the description which follows of an example of its embodiment illustrated by the appended drawings in which:
  • Figure 1 is a schematic view of a starting flap mechanism which can be applied the pneumatic control device according to the invention, shown in the position "choke fully drawn", immediately after starting the engine;
  • Figure 2 is a view of the mechanism of Figure 1, shown in the partially pushed back position of the choke; and
  • Figure 3 is a longitudinal sectional view of the pneumatic control device according to the invention.

La figure 1 illustre schématiquement le mécanisme à volet de départ d'un carburateur dont on a représenté en traits fins le contour du corps 1, supposé transparent pour la clarté du dessin.Figure 1 schematically illustrates the starting flap mechanism of a carburetor which has been shown in fine lines the outline of the body 1, assumed transparent for clarity of the drawing.

Le corps 1 comporte un venturi 2 dans lequel est monté un dispositif de giclage de carburant 3. En avant du venturi 2, un papillon des gaz 4 est monté rotatif autour d'un axe excentré 5 entre une position de fermeture complète délimitée par une butée 6 et une position d'ouverture totale. La rotation du papillon 4 est commandée par un levier 7 auquel est accroché un ressort 8 sollicitant le papillon 4 vers sa position de fermeture.The body 1 comprises a venturi 2 in which is mounted a fuel spray device 3. In front of the venturi 2, a throttle valve 4 is rotatably mounted about an eccentric axis 5 between a fully closed position delimited by a stop 6 and a fully open position. The rotation of the butterfly 4 is controlled by a lever 7 to which is hooked a spring 8 urging the butterfly 4 to its closed position.

Un volet d'air 9 pour le départ à froid est également monté rotatif autour d'un axe excentré 10 dans le corps 1, en amont du venturi 2. Ce volet peut basculer entre une position de fermeture complète délimitée par une butée 11 et une position d'ouverture totale. L'axe 10 est solidaire d'une extrémité d'un levier 12 qui commande les mouvements du volet d'air 9 entre ses positions ouverte et fermée. Un ressort 13 accroché au levier 12 sollicite le volet 9 vers sa position de fermeture.An air flap 9 for the cold start is also rotatably mounted around an eccentric axis 10 in the body 1, upstream of the venturi 2. This flap can switch between a completely closed position delimited by a stop 11 and a fully open position. The axis 10 is integral with one end of a lever 12 which controls the movements of the air flap 9 between its open and closed positions. A spring 13 hooked to the lever 12 biases the flap 9 towards its closed position.

L'autre extrémité du levier 12 est reliée par une tringle 14 à un dispositif de commande pneumatique 16 qui sera décrit ci-après. Une came 25 est articulée autour d'un axe 26 parallèle aux axes 5 et 10. Les mouvements de rotation de la came 25 autour de son axe 26 sont commandés par un levier 27 solidaire de l'axe 26 et une tringle 28 à actionnement manuel. Une partie du contour extérieur de la came 25 constitue une première surface de came D avec laquelle coopère l'extrémité libre du levier 7 pour entrouvrir le papillon 4 lorsque le starter est tiré à fond. La came 25 comporte un appendice 30 en forme de crochet dont le contour intérieur constitue une surface de came F prolongeant une autre surface de came E. Cette surface E est définie par une seconde partie du contour extérieur de la came 25 et coopère avec l'articulation 23 du levier 12 avec la tringle 14 pour définir la position d'ouverture minimale du volet d'air lorsque le starter est partiellement repoussé, et maintenir ce volet totalement ouvert lorsque le starter est complètement repoussé.The other end of the lever 12 is connected by a rod 14 to a pneumatic control device 16 which will be described below. A cam 25 is articulated around an axis 26 parallel to the axes 5 and 10. The rotational movements of the cam 25 around its axis 26 are controlled by a lever 27 integral with the axis 26 and a rod 28 with manual actuation . A part of the outer contour of the cam 25 constitutes a first cam surface D with which the free end of the lever 7 cooperates to half-open the butterfly valve 4 when the choke is fully pulled. The cam 25 has a hook-shaped appendage 30 whose internal contour constitutes a cam surface F extending another cam surface E. This surface E is defined by a second part of the external contour of the cam 25 and cooperates with the articulation 23 of the lever 12 with the rod 14 to define the minimum open position of the air shutter when the choke is partially pushed back, and keep this shutter fully open when the choke is fully pushed back.

En fonctionnement, préalablement au démarrage du moteur, lorsque le starter est tiré à fond et que la came 25 occupe la position représentée à la figure 1, le volet 9 est complètement fermé par la traction exercée par le ressort 13, tandis que le papillon 4 est entrouvert par l'interaction entre la surface de came D et le levier 7.In operation, before starting the engine, when the choke is fully pulled and the cam 25 occupies the position shown in FIG. 1, the flap 9 is completely closed by the traction exerted by the spring 13, while the butterfly 4 is ajar by the interaction between the cam surface D and the lever 7.

Dès le démarrage du moteur, la dépression du collecteur d'admission est appliquée au dispositif de commande 16 et l'articulation 23 est appliquée contre la surface de came F. Le volet 9 prend alors une position entrebâillée comme le montre la figure 1.As soon as the engine starts, the vacuum in the intake manifold is applied to the control device 16 and the articulation 23 is applied against the cam surface F. The flap 9 then takes a half-open position as shown in FIG. 1.

A la première « repoussée du starter, l'appendice 30, qui joue le rôle de butée, est escamoté par la rotation de la came 25, comme le montre la figure 2 : en effet, dans cette position de la came 25, le levier 12 est libre de basculer entre la position d'ouverture totale du volet de la figure 2 et une position d'ouverture minimale délimitée par la venue en appui de l'articulation 23 contre la surface de came E.At the first "push of the choke, the appendix 30, which acts as a stop, is retracted by the rotation of the cam 25, as shown in FIG. 2: in fact, in this position of the cam 25, the lever 12 is free to switch between the fully open position of the shutter of FIG. 2 and a minimum open position defined by the abutment of the joint 23 against the cam surface E.

Par conséquent, la position du volet de départ 9, et donc l'enrichissement du mélange, dépendent alors des conditions de fonctionnement du moteur. C'est ainsi que, au ralenti, en décélération ou en vitesse stabilisée, la dépression dans le collecteur d'admission est forte car l'ouverture du papillon des gaz est faible, et le volet d'air 9 est complètement ouvert. Le moteur, bien que froid, fonctionne avec un mélange non enrichi identique à celui qui lui est fourni à chaud. Par contre, dès que, lors d'une accélération ou en côte, le papillon des gaz est largement ouvert, la dépression au collecteur d'admission diminue rapidement et le ressort 13, convenablement dimensionné, rappelle immédiatement le volet 9 dans sa position d'ouverture imposée par la rampe E.Consequently, the position of the starting flap 9, and therefore the enrichment of the mixture, then depend on the operating conditions of the engine. Thus, at idle, deceleration or stabilized speed, the vacuum in the intake manifold is high because the opening of the throttle valve is small, and the air flap 9 is fully open. The engine, although cold, operates with an unenriched mixture identical to that supplied to it hot. By cons, as soon as, during acceleration or uphill, the throttle valve is wide open, the vacuum at the intake manifold decreases rapidly and the spring 13, suitably sized, immediately returns the flap 9 to its position opening imposed by ramp E.

On se reportera maintenant à la figure 3 qui montre le dispositif de commande pneumatique 16 permettant d'assurer une pleine ouverture du volet d'air 9, même lorsque la dépression dans le collecteur d'admission est faible, tout en assurant la fermeture de ce volet 9 pour une très faible variation de cette dépression en début d'accélération.Reference will now be made to FIG. 3 which shows the pneumatic control device 16 making it possible to ensure full opening of the air flap 9, even when the vacuum in the intake manifold is low, while ensuring the closing of this flap 9 for a very small variation of this depression at the start of acceleration.

Ce dispositif comprend deux capsules pneumatiques 101 et 102 liées rigidement entre elles par des pièces 103 et 104. La tringle 14 est solidaire d'une membrane 106 de la première capsule 101, dont la chambre gauche 101 A, par rapport à la membrane 106, est soumise à la pression atmosphérique. La chambre droite 101 B de la capsule 101 comporte un ressort 107, ayant un tarage permettant le déplacement de la membrane 106 sous une dépression très faible dans le collecteur d'admission (non représenté). Ce déplacement assure l'ouverture complète du volet 9, par l'intermédiaire de la tringle 14. La chambre 101 B de la capsule 101 où se trouve le ressort 107 est soumise à la dépression régnant dans le collecteur d'admission par un conduit 108 dans lequel se trouve un calibrage 109 et elle comporte un orifice 101 C de mise à l'atmosphère contrôlée.This device comprises two pneumatic capsules 101 and 102 rigidly connected to each other by parts 103 and 104. The rod 14 is integral with a membrane 106 of the first capsule 101, of which the left chamber 101 A, relative to the membrane 106, is subjected to atmospheric pressure. The straight chamber 101 B of the capsule 101 comprises a spring 107, having a calibration allowing the displacement of the membrane 106 under a very low vacuum in the intake manifold (not shown). This movement ensures the complete opening of the flap 9, via the rod 14. The chamber 101 B of the capsule 101 where the spring 107 is located is subjected to the vacuum prevailing in the intake manifold by a conduit 108 in which there is a calibration 109 and it includes an orifice 101 C for setting the controlled atmosphere.

L'étanchéité de la chambre 101 B par rapport à l'atmosphère est réalisée à l'aide d'un bouchon 110 fermant l'orifice 101 C et solidaire d'une tige 111 de la capsule 102. Cette tige est accrochée à la membrane 112 de la capsule 102. La capsule 102 comporte deux chambres 102 A et 102 B qui sont séparées par la membrane 112. La chambre 102 A est soumise à la dépression régnant dans le collecteur d'admission par l'intermédiaire d'un conduit 113. L'étanchéité par rapport à l'atmosphère de la chambre 102 A de la capsule 102 est assurée par un soufflet 117 qui est serré d'un côté sur la tige 111, et de l'autre, sur la coquille gauche 105 de la capsule 102. La chambre droite 102 B de la capsule 102 comporte un ressort 114, qui a un tarage très faible pour qu'une faible dépression de 50 g/cm2 environ puisse déplacer la membrane 112, et en conséquence le bouchon 110, pour mettre à la pression atmosphérique la chambre 101 A de la capsule 101. La chambre droite 102 B de la capsule 102 est soumise à la dépression régnant au collecteur d'admission par l'intermédiaire d'un conduit 115, dans lequel est placé un calibrage 116.The sealing of the chamber 101 B with respect to the atmosphere is carried out using a plug 110 closing the orifice 101 C and secured to a rod 111 of the capsule 102. This rod is attached to the membrane 112 of the capsule 102. The capsule 102 comprises two chambers 102 A and 102 B which are separated by the membrane 112. The chamber 102 A is subjected to the vacuum prevailing in the intake manifold via a conduit 113 The seal with respect to the atmosphere of the chamber 102 A of the capsule 102 is ensured by a bellows 117 which is tightened on one side on the rod 111, and on the other, on the left shell 105 of the capsule 102. The straight chamber 102 B of the capsule 102 comprises a spring 114, which has a very low calibration so that a low depression of approximately 50 g / cm 2 can move the membrane 112, and consequently the plug 110, to bring the chamber 101 A of the capsule 101 to atmospheric pressure. The right chamber 102 B of the capsule 102 is subjected to the vacuum prevailing at the intake manifold via a conduit 115, in which a calibration 116 is placed.

En fonctionnement, après le départ du moteur, la dépression dans le collecteur d'admission est forte. Cette dépression appliquée par l'intermédiaire du conduit 108 et du calibrage 109 dans la chambre droite 101 B de la capsule 101 agit sur la membrane 106, qui comprime le ressort 107. La membrane 106 déplace la tringle 14 et le volet de départ 9 est ouvert.In operation, after the engine has started, the vacuum in the intake manifold is strong. This vacuum applied via the conduit 108 and the calibration 109 in the right chamber 101 B of the capsule 101 acts on the membrane 106, which compresses the spring 107. The membrane 106 moves the rod 14 and the starting flap 9 is open.

Les deux chambres de la capsule 102 sont soumises à la dépression dans le collecteur d'admission, mais l'établissement de cette dépression dans la partie droite se fait avec un retard à cause du calibrage 116. Lors d'une baisse de dépression dans le collecteur, suite à une faible accélération, l'équilibre de dépression dans les deux chambres de la capsule 102 est rompu : la dépression diminue immédiatement dans la chambre gauche 102 A de la capsule 102, mais par contre, cette diminution de la dépression dans la chambre droite 102 B de la capsule 102 est retardée par le calibrage 116.The two chambers of the capsule 102 are subjected to the vacuum in the intake manifold, but the establishment of this vacuum in the right-hand part takes place with a delay because of the calibration 116. During a drop in vacuum in the collector, following a weak acceleration, the depression balance in the two chambers of the capsule 102 is broken: the depression immediately decreases in the left chamber 102 A of the capsule 102, but on the other hand, this reduction in depression in the straight chamber 102 B of the capsule 102 is delayed by the calibration 116.

Ce déséquilibre des dépressions provoque la compression du ressort 114 par la membrane 112 et le déplacement de la tige 111 avec son bouchon 110, et la chambre droite 101 B de la capsule 101 est mise à la pression atmosphérique par l'orifice 101 C. En conséquence, le ressort 107 repousse la membrane 106 qui déplace la tringle 14 et le volet 9 se ferme. Le mélange air/combustible devient plus riche.This imbalance of depressions causes the compression of the spring 114 by the membrane 112 and the displacement of the rod 111 with its plug 110, and the straight chamber 101 B of the capsule 101 is brought to atmospheric pressure through the orifice 101 C. In Consequently, the spring 107 pushes back the membrane 106 which moves the rod 14 and the shutter 9 closes. The air / fuel mixture becomes richer.

Dès que le régime du moteur se stabilise, l'équilibre des dépressions s'établit dans les deux chambres de la capsule 102: le ressort 114 repousse la membrane 112 qui déplace la tige 111 avec son bouchon 110, lequel obture l'orifice de la mise à l'atmosphère de la chambre droite 101 B de la capsule 101. Il en résulte qu'une dépression se rétablit dans la chambre droite 101 B de la capsule 101. Cette dépression attire la membrane 106 qui comprime le ressort 107, et la tringle 14 ouvre le volet 9 dans une position qui dépend de l'équilibre établi entre cette dépression, elle-même fonction de la position du papillon 4, et de la force antagoniste des ressorts 13 et 107.As soon as the engine speed stabilizes, the balance of depressions is established in the two chambers of the capsule 102: the spring 114 repels the membrane 112 which moves the rod 111 with its plug 110, which closes the orifice of the venting the right chamber 101 B of the capsule 101. As a result, a depression is restored in the right chamber 101 B of the capsule 101. This depression attracts the membrane 106 which compresses the spring 107, and the rod 14 opens the shutter 9 in a position which depends on the balance established between this depression, itself a function of the position of the butterfly 4, and of the opposing force of the springs 13 and 107.

Claims (5)

1. A device for pneumatically controlling the air throttle member of a carburettor for an internal combustion engine, in which carburettor, during operation of the engine in the cold condition, the pivotal movement of the air throttle member is controlled in dependence on the engine load between a position of minimum opening corresponding to the full load operating condition of the engine and a position of a maximum opening corresponding to a low load operating condition of the engine, said control device (16) comprising a capsule (101) having two chambers (101 A, 101 B) which are separated by a drive element (106) connected to the air throttle member by a linkage and subjected to the force of a return spring (107) urging the drive element (106) in the direction of tending to close the air throttle member, the first (101 A) of the two chambers being subjected to atmospheric pressure and the second chamber (101 B) being subjected to the depression of the intake manifold, characterised in that the second chamber (101 B) has an orifice (101 C) for forming a controlled communication with atmosphere, that the control device comprises a second capsule (102) which operates in a differential mode and which is adapted to open the orifice (101 C) in response to small variations in the depression in the intake manifold, that the second capsule (102) comprises a drive element (112) which is fixed with respect to a rod (111) which at its free end carries a closure member (110) for controlling closure of the orifice (101 C) for controlled communication with atmosphere, and that the drive element (112) of the second capsule (102) defines a first chamber (102 A) directly subjected to the depression of the intake manifold by way of a conduit (113) and a second chamber (102 B) subjected to the depression of the intake manifold by way of another conduit (115) in which there is disposed a calibration means (116), a return spring (114) urging the drive element (112) in the direction of tending to close the orifice (101 C) for controlled communication with atmosphere.
2. A device according to claim 1 characterised in that said rod (111) passes through the first chamber (102 A) of the second capsule (102) sealingly by means of a bellows (117) which is airtightly fixed to the rod (111) on the one hand and to the second capsule (102) on the other hand.
3. A device according to claim 1 or claim 2 characterised in that the first and second capsules (101, 102) are rigidly fixed together.
4. A device according to any one of claims 1, 2 and 3 characterised in that, as is known per se, the drive element of the first and second capsules (101, 102) is a diaphragm (106, 112) and the corresponding return spring (107, 114) is disposed in the second chamber (101 B, 102 B) of the capsules (101, 102).
5. A device according to any one of claims 1 to 4 characterised in that the second chamber (101 B) of the first capsule (101) is subjected to the depression of the intake manifold by way of a conduit (108) comprising a calibration means (109).
EP19830400411 1982-03-04 1983-03-01 Pneumatic control device for a carburettor air throttle of an internal combustion engine Expired EP0088678B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8203574 1982-03-04
FR8203574A FR2522729A1 (en) 1982-03-04 1982-03-04 PNEUMATIC CONTROL DEVICE FOR THE AIR FLAP OF A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE

Publications (2)

Publication Number Publication Date
EP0088678A1 EP0088678A1 (en) 1983-09-14
EP0088678B1 true EP0088678B1 (en) 1985-11-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP19830400411 Expired EP0088678B1 (en) 1982-03-04 1983-03-01 Pneumatic control device for a carburettor air throttle of an internal combustion engine

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EP (1) EP0088678B1 (en)
DE (1) DE3361260D1 (en)
ES (1) ES8401572A1 (en)
FR (1) FR2522729A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0295398B1 (en) * 1987-06-15 1991-09-18 Firma Andreas Stihl Starting device for an internal combustion engine, especially for a hand-started motor of a tool
DE3842974A1 (en) * 1988-12-21 1990-06-28 Stihl Maschf Andreas DIAPHRAGM CARBURETTOR WITH POSITIONALLY COUPLED THROTTLE VALVE AND CHOKE VALVE

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930475A (en) * 1973-08-24 1976-01-06 Ford Motor Company Engine exhaust gas recirculating control
JPS5234512Y2 (en) * 1974-11-30 1977-08-06
FR2393161A1 (en) * 1977-06-02 1978-12-29 Sibe IMPROVEMENTS FOR CARBURETTORS EQUIPPED WITH A STARTING ASPECT

Also Published As

Publication number Publication date
ES520266A0 (en) 1983-12-01
ES8401572A1 (en) 1983-12-01
EP0088678A1 (en) 1983-09-14
FR2522729A1 (en) 1983-09-09
DE3361260D1 (en) 1986-01-02
FR2522729B1 (en) 1984-05-04

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