EP0371841B1 - Cooling circuit for an internal-combustion engine of a motor vehicle - Google Patents

Cooling circuit for an internal-combustion engine of a motor vehicle Download PDF

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Publication number
EP0371841B1
EP0371841B1 EP19890403089 EP89403089A EP0371841B1 EP 0371841 B1 EP0371841 B1 EP 0371841B1 EP 19890403089 EP19890403089 EP 19890403089 EP 89403089 A EP89403089 A EP 89403089A EP 0371841 B1 EP0371841 B1 EP 0371841B1
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EP
European Patent Office
Prior art keywords
pump
valve
duct
thermostat
pipe
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP19890403089
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German (de)
French (fr)
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EP0371841A1 (en
Inventor
Michel Leborne
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Automobiles Peugeot SA
Automobiles Citroen SA
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Automobiles Peugeot SA
Automobiles Citroen SA
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Publication of EP0371841A1 publication Critical patent/EP0371841A1/en
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Publication of EP0371841B1 publication Critical patent/EP0371841B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P11/00—Component parts, details, or accessories not provided for in, or of interest apart from, groups F01P1/00 - F01P9/00
    • F01P11/02—Liquid-coolant filling, overflow, venting, or draining devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B3/00—Engines characterised by air compression and subsequent fuel addition
    • F02B3/06—Engines characterised by air compression and subsequent fuel addition with compression ignition

Definitions

  • the present invention relates to a liquid cooling circuit, such as water, of an internal combustion engine of a motor vehicle.
  • Such circuits are generally known comprising a pump for supplying coolant to the engine having an outlet connected to the engine and an inlet connected on the one hand to a radiator for cooling the liquid by a pipe whose downstream end comprises a thermostat. with valve the opening of which occurs when the temperature of the fluid reaches a predetermined upper threshold value and on the other hand to an expansion vessel by another pipe comprising a valve member whose opening ensures the flow of the fluid only in the expansion tank to pump direction.
  • the closed position of the thermostat valve makes it possible to deactivate a part of the circuit when the engine is cold, in particular that relating to the circulation of the fluid leaving the cylinder head of the engine and going to the pump via the radiator so as to accelerate the temperature rises of the liquid in the engine and in the exchanger device (air heater) used for heating the passenger compartment of the vehicle.
  • the heating performance in the passenger compartment of the vehicle is improved in particular in cold weather, at low engine speeds and loads.
  • EP-A-O 157 167 describes a cooling circuit comprising the characteristics set out in the preamble of claim 1.
  • the present invention proposes, with respect to the above prior document, a cooling circuit according to which the thermostat and the valve member form a compact unit and therefore compact.
  • valve member is arranged at the downstream end of the pipe, is housed with the pre-stressed spring calibrated at the threshold value in a body integrated in the body of the thermostat so that the retaining spring the member is parallel to the valve retaining spring, is located in an annular chamber formed in a bulge in the downstream end of the pipe connecting the radiator to the pump and is in the form of a flat ring coaxially surrounding the spring of holding, the sealing seat of the valve member and the sealing seat of the thermostat valve being formed in the body of the thermostat.
  • the reference 1 designates an internal combustion engine of a motor vehicle comprising a cylinder block (not shown) surmounted by a cylinder head 2 with outlet connector 3.
  • a pipe 4 connects an outlet of the cylinder head 2 at the inlet of a radiator 5 for cooling an engine fluid.
  • the radiator outlet 5 is connected to an inlet pipe 6a of a pump 6 via a pipe 7, the outlet of the pump 6 being connected to the cylinder block of the engine 1 via a line 8 for injecting engine coolant.
  • a permanent bypass or bypass pipe 9 connects an outlet of the cylinder head 2 to the pump 6.
  • a pipe 10 connects the outlet of the cylinder head 2 to the inlet of a heat exchanger device (air heater) 11 for heating of the passenger compartment of the vehicle and the outlet of which is connected to a pipe 12 which is connected in communication with the fluid to the pipe 9.
  • An air-engine oil exchanger device 13 is connected to the outlet of the cylinder head 2 by a pipe 14 and to its outlet connecting in fluid communication to the pipe 7 by a pipe 15.
  • An expansion tank 16 is connected by a pipe 17 to the outlet of the cylinder head 2 and to its outlet connected to the inlet pipe 6a of the pump 6 via line 18.
  • a thermostat device 19 blocking the passage of the fluid in the pipe 7 towards the pipe 6a for temperature values of the fluid in the pipe 7 less than a predetermined value, for example 80 ° C.
  • the pipe 18 comprises, at one, upstream or downstream, of its ends, a valve member the open position of which allows the fluid to flow only in the direction of the expansion tank 16 towards the pump 6.
  • valve member 20 is disposed in a downstream end portion of the pipe 18 preferably opening, when the valve member 20 is open, downstream of the valve of the thermostat device 19
  • the arrival of the fluid coming from the expansion tank 16 is located upstream of the thermostat device 19 and the end of the pipe 18 is extended by a through part 21 in which the sealing seat is located. 22 of the valve member 20 which is held in the closed position in abutment against the seat 22 downstream of this seat by a prestressed spring 23 disposed in the end portion of the through part parallel to the direction of flow of the fluid in the tubing inlet 6a of the pump 6.
  • the arrival of the fluid coming from the expansion tank 16 is located downstream of the thermostat device 19 and the end part of the pipe 18 is extended by the through part 21 comprising the spring 23 also parallel to the direction of flow of the fluid in the tube 6a and maintaining the valve member 20 in the closed position against its sealing seat 22 which is thus located downstream of the thermostat device 19.
  • FIG 4 shows in detail a particular embodiment of the arrangement corresponding to that shown in Figure 2.
  • the downstream end portion of the pipe 7 has a bulge 7a in which is defined the through portion 21 in the form of chamber annular arranged coaxially to the longitudinal axis of the inlet pipe 6a and in fluid communication with the pipe 18 by means of a radial opening 7b produced in the bulge 7a and opening outwardly, the downstream end of the pipe 18 can be fitted into the orifice 7b.
  • the annular chamber 21 thus comprises a dome-shaped part defining an internal annular wall 7c of the pipe 7 and an external annular wall 7d for connection to the pipe 6a.
  • a frustoconical opening is defined against which abuts, by means of a seal J1, a portion of the upper part in frusto-cone 24a of the body 24 of the thermostat device 19.
  • Part 24a is surmounted by an upper terminal structure with three ribs 24b arranged at 120 degrees relative to each other and converging in line 7 into a common central part in the form of a cap 25 to which they are connected .
  • the upper face of the frusto-conical part 24a has three orifices 24a1 allowing the passage of fluid in the pipe 7 towards the inlet pipe 6a when the valve 26 of the thermostat device 19 is released from its sealing seat formed in the frusto-conical part 24a just downstream from holes 24a1.
  • the thermostat device 19 is of the thermostatic capsule 27 type, known per se, in the form of a generally cylindrical body arranged coaxially with the pipe 6a while extending on either side of the connection plane of the pipe 7 to the pipe. 6a.
  • the capsule ends at its upper part with respect to FIG. 4 by a rod 27a, the free end of which bears on the cap 25 and on which the body of the capsule is capable of moving coaxially with the longitudinal axis of the tubing 6a.
  • the valve 26 consists of a metal plate in the form of a washer 26a coaxial with the longitudinal axis of the tube 6a and integral with the body of the capsule 27.
  • the circular end part of the plate 26a is embedded in a joint d sealing 26b, the external part of which ensuring the tight sealing of the orifices 24a1 is of frustoconical shape.
  • the body 24 has a cylindrical wall 24c connecting to the frustoconical wall 24a by means of an annular plane wall 24d perpendicular to the wall 24c.
  • the wall 24c ends in an external annular rim 24e embedded in an annular seal 28 between the pipe 7 and the pipe 6a.
  • the body 24 further comprises in its lower part three branches 24f, only one of which is shown in Figure 4, and arranged at 120 degrees from each other.
  • Each branch ends in a cup-shaped part 24f1 against which the end turn of a pre-stressed spring 29 bears, the opposite end turn of which rests in the seal 26b so as to keep the seal 26b in pressure pressed against the valve sealing seat 26 in the closed position thereof.
  • the annular wall 24d has orifices 24d1 for the passage of the fluid in the pipe 18 towards the tube 6a and acts as a sealing seat for the valve-forming member 20 in the form flat ring coaxially surrounding the spring 29. It is thus understood that the sealing seat of the valve 26 and the sealing seat of the valve member are made in one piece.
  • the valve member 20 has on its upper face an annular sealing gasket 30.
  • the valve member 20 is disposed in a body 31 generally in shape of cylindrical ring integrated in the cylindrical wall 24c while being integral with the latter.
  • the body 31 has a lower spring retaining rim 23 mounted in this way prestressed between this rim and the valve member 20, parallel to the spring 29.
  • the valve member 20 is located downstream of the valve sealing seat 26 .
  • the valve 26 of the thermostat device 19 is closed so that the fluid passage circuits comprising respectively the line 4, the radiator 5, the line 7 and the line 14, the exchanger 13, the line 15 is out of service.
  • the valve member remains closed and the fluid circuit comprising the line 17, the expansion tank 16 and line 18 is out of service. In this way, there is a rapid rise in temperature in the engine and in the exchanger 11.
  • the vacuum at pump inlet reaches a given threshold value slightly lower than the depression causing the fluid to cavitate.
  • valve member 20 opens, the spring 23 being calibrated in correspondence with the threshold value, and puts in communication the additional fluid circuit formed by the pipe 17, the expansion tank 16 and the pipe 18 , in addition to the permanent bypass 9 and the pipe circuit 10, exchanger 11, pipe 12, with the inlet manifold 6a of the pump 6.
  • the two curves in solid lines A ′ and B ′ represent respectively the inlet and outlet pressures of the pump with a conventional thermostat device.
  • the body 27 is lowered with the valve 26, thus authorizing the flow of the fluid in the pipe 7 towards the tubing 6a through the orifices 24a1.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Temperature-Responsive Valves (AREA)

Description

La présente invention concerne un circuit de refroidissement par un liquide, tel que de l'eau, d'un moteur à combustion interne d'un véhicule automobile.The present invention relates to a liquid cooling circuit, such as water, of an internal combustion engine of a motor vehicle.

On connaît de tels circuits comprenant généralement une pompe d'alimentation en fluide de refroidissement du moteur ayant une sortie reliée au moteur et une entrée reliée d'une part à un radiateur de refroidissement du liquide par une conduite dont l'extrémité aval comporte un thermostat à soupape dont l'ouverture se produit lorsque la température du fluide atteint une valeur de seuil supérieure prédéterminée et d'autre part à un vase d'expansion par une autre conduite comportant un organe formant clapet dont l'ouverture assure l'écoulement du fluide uniquement dans le sens vase d'expansion vers pompe.Such circuits are generally known comprising a pump for supplying coolant to the engine having an outlet connected to the engine and an inlet connected on the one hand to a radiator for cooling the liquid by a pipe whose downstream end comprises a thermostat. with valve the opening of which occurs when the temperature of the fluid reaches a predetermined upper threshold value and on the other hand to an expansion vessel by another pipe comprising a valve member whose opening ensures the flow of the fluid only in the expansion tank to pump direction.

La position de fermeture de la soupape du thermostat permet de mettre hors service lorsque le moteur est froid une partie du circuit notamment celle relative à la circulation du fluide sortant de la culasse du moteur et allant vers la pompe en passant par le radiateur de façon à accélérer les montées en température du liquide dans le moteur et dans le dispositif échangeur (aérotherme) utilisé pour le chauffage de l'habitacle du véhicule. Ainsi, les prestations de chauffage dans l'habitacle du véhicule sont améliorées notamment par temps froid, aux faibles régimes et charges du moteur.The closed position of the thermostat valve makes it possible to deactivate a part of the circuit when the engine is cold, in particular that relating to the circulation of the fluid leaving the cylinder head of the engine and going to the pump via the radiator so as to accelerate the temperature rises of the liquid in the engine and in the exchanger device (air heater) used for heating the passenger compartment of the vehicle. Thus, the heating performance in the passenger compartment of the vehicle is improved in particular in cold weather, at low engine speeds and loads.

Cependant, si la mise hors service au moyen du thermostat en amont de la pompe de la partie précitée du circuit répond au problème de la montée rapide en température du fluide sortant de la culasse pour un chauffage rapide de l'habitacle du véhicule, elle engendre, à l'entrée de la pompe, une dépression pouvant produire une cavitation du fluide surtout dans le cas de moteurs à débits internes importants, tels que les moteurs diesel modernes. Cette cavitation détériore rapidement les pièces où elle se produit.However, if the deactivation by means of the thermostat upstream of the pump of the aforementioned part of the circuit addresses the problem of the rapid rise in temperature of the fluid leaving the cylinder head for rapid heating of the passenger compartment of the vehicle, it generates a vacuum at the inlet of the pump which can produce cavitation of the fluid, especially in the case of engines with large internal flow rates, such as modern diesel engines. This cavitation rapidly deteriorates the parts where it occurs.

EP-A-O 157 167 décrit un circuit de refroidissement comportant les caractéristiques énoncées au préambule de la revendication 1.EP-A-O 157 167 describes a cooling circuit comprising the characteristics set out in the preamble of claim 1.

La présente invention propose par rapport au document antérieur ci-dessus un circuit de refroidissement selon lequel le thermostat et l'organe formant clapet forment un ensemble compact et donc peu encombrant.The present invention proposes, with respect to the above prior document, a cooling circuit according to which the thermostat and the valve member form a compact unit and therefore compact.

A cet effet, l'organe formant clapet est disposé à l'extrémité aval de la conduite, est logé avec le ressort précontraint taré à la valeur de seuil dans un corps intégré dans le corps du thermostat de telle façon que le ressort de maintien de l'organe soit parallèle au ressort de maintien de la soupape, est situé dans une chambre annulaire réalisée dans un renflement de l'extrémité aval de la conduite reliant le radiateur à la pompe et est en forme d'anneau plat entourant coaxialement le ressort de maintien, le siège d'étanchéité de l'organe formant clapet et le siège d'étanchéité de la soupape de thermostat étant réalisés dans le corps du thermostat.To this end, the valve member is arranged at the downstream end of the pipe, is housed with the pre-stressed spring calibrated at the threshold value in a body integrated in the body of the thermostat so that the retaining spring the member is parallel to the valve retaining spring, is located in an annular chamber formed in a bulge in the downstream end of the pipe connecting the radiator to the pump and is in the form of a flat ring coaxially surrounding the spring of holding, the sealing seat of the valve member and the sealing seat of the thermostat valve being formed in the body of the thermostat.

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

  • La figure 1 représente un circuit de fluide pour le refroidissement d'un moteur à combustion interne et le chauffage de l'habitacle du véhicule comportant ce moteur;
  • Les figures 2 et 3 représentent respectivement schématiquement deux emplacements possibles de l'organe formant clapet pour limiter la dépression à l'entrée de la pompe du circuit de la figure 1;
  • La figure 4 représente en coupe un mode de réalisation détaillé de l'agencement représenté en figure 2;
  • La figure 5 est une vue suivant la flèche V de la figure 4 d'une pièce de l'agencement;
  • La figure 6 représente l'évolution des pressions aux entrée et sortie de la pompe en fonction du débit du fluide.
The invention will be better understood, and other objects, details and advantages thereof will appear more clearly during the explanatory description which follows, made with reference to the appended schematic drawings given solely by way of example illustrating several modes of realization of the invention, and in which:
  • FIG. 1 represents a fluid circuit for cooling an internal combustion engine and heating the passenger compartment of the vehicle comprising this engine;
  • Figures 2 and 3 schematically respectively represent two possible locations of the valve member for limiting the vacuum at the inlet of the pump of the circuit of Figure 1;
  • Figure 4 shows in section an embodiment detailed arrangement shown in Figure 2;
  • Figure 5 is a view along arrow V of Figure 4 of a part of the arrangement;
  • FIG. 6 represents the evolution of the pressures at the inlet and outlet of the pump as a function of the flow of the fluid.

En se reportant à la figure 1, la référence 1 désigne un moteur à combustion interne d'un véhicule automobile comportant un bloc-cylindres (non représenté) surmonté d'une culasse 2 à raccord de sortie 3. Une conduite 4 relie une sortie de la culasse 2 à l'entrée d'un radiateur 5 de refroidissement d'un fluide du moteur. La sortie de radiateur 5 est reliée à une tubulure d'entrée 6a d'une pompe 6 par l'intermédiaire d'une conduite 7, la sortie de la pompe 6 étant reliée au bloc-cylindres du moteur 1 par l'intermédiaire d'une conduite 8 pour injecter du fluide de refroidissement du moteur. Une conduite de dérivation ou by-pass permanent 9 relie une sortie de la culasse 2 à la pompe 6. Une conduite 10 relie la sortie de la culasse 2 à l'entrée d'un dispositif échangeur de chaleur (aérotherme) 11 pour le chauffage de l'habitacle du véhicule et dont la sortie est reliée à une conduite 12 se raccordant en communication du fluide à la conduite 9. Un dispositif échangeur air-huile moteur 13 est raccordé à la sortie de la culasse 2 par une conduite 14 et à sa sortie se raccordant en communication de fluide à la conduite 7 par une conduite 15. Un vase d'expansion 16 est raccordé par une conduite 17 à la sortie de la culasse 2 et à sa sortie reliée à la tubulure d'entrée 6a de la pompe 6 par une conduite 18.Referring to FIG. 1, the reference 1 designates an internal combustion engine of a motor vehicle comprising a cylinder block (not shown) surmounted by a cylinder head 2 with outlet connector 3. A pipe 4 connects an outlet of the cylinder head 2 at the inlet of a radiator 5 for cooling an engine fluid. The radiator outlet 5 is connected to an inlet pipe 6a of a pump 6 via a pipe 7, the outlet of the pump 6 being connected to the cylinder block of the engine 1 via a line 8 for injecting engine coolant. A permanent bypass or bypass pipe 9 connects an outlet of the cylinder head 2 to the pump 6. A pipe 10 connects the outlet of the cylinder head 2 to the inlet of a heat exchanger device (air heater) 11 for heating of the passenger compartment of the vehicle and the outlet of which is connected to a pipe 12 which is connected in communication with the fluid to the pipe 9. An air-engine oil exchanger device 13 is connected to the outlet of the cylinder head 2 by a pipe 14 and to its outlet connecting in fluid communication to the pipe 7 by a pipe 15. An expansion tank 16 is connected by a pipe 17 to the outlet of the cylinder head 2 and to its outlet connected to the inlet pipe 6a of the pump 6 via line 18.

Dans la zone de raccordement de l'extrémité aval de la conduite 7 à l'entrée de la tubulure 6a de la pompe 6 est disposé un dispositif thermostat 19 obturant le passage du fluide dans la conduite 7 vers la tubulure 6a pour des valeurs de température du fluide dans la conduite 7 inférieures à une valeur prédéterminée, par exemple de 80°C.In the connection area of the downstream end of the pipe 7 to the inlet of the pipe 6a of the pump 6 is arranged a thermostat device 19 blocking the passage of the fluid in the pipe 7 towards the pipe 6a for temperature values of the fluid in the pipe 7 less than a predetermined value, for example 80 ° C.

Les différents éléments du circuit ci-dessus décrits de la figure 1 étant déjà connus tant du point de vue structure que fonctionnement, ils n'ont pas à être décrits plus en détail.The various elements of the circuit described above in FIG. 1 being already known both from the structural and operating point of view, they need not be described in more detail.

La conduite 18 comporte à l'une, amont ou aval, de ses extrémités un organe formant clapet dont la position d'ouverture permet l'écoulement du fluide uniquement dans le sens du vase d'expansion 16 vers la pompe 6.The pipe 18 comprises, at one, upstream or downstream, of its ends, a valve member the open position of which allows the fluid to flow only in the direction of the expansion tank 16 towards the pump 6.

Comme représenté aux figures 2 et 3, l'organe formant clapet 20 est disposé dans une partie d'extrémité aval de la conduite 18 débouchant de préférence, lorsque l'organe formant clapet 20 est ouvert, en aval de la soupape du dispositif thermostat 19. Selon la figure 2, l'arrivée du fluide provenant du vase d'expansion 16 est située en amont du dispositif thermostat 19 et l'extrémité de la conduite 18 se prolonge par une partie débouchante 21 dans laquelle se trouve le siège d'étanchéité 22 de l'organe formant clapet 20 qui est maintenu en position fermée en appui contre le siège 22 en aval de ce siège par un ressort précontraint 23 disposé dans la portion terminale de la partie débouchante parallèlement au sens d'écoulement du fluide dans la tubulure d'entrée 6a de la pompe 6. Suivant la figure 3, l'arrivée du fluide provenant du vase d'expansion 16 est située en aval du dispositif thermostat 19 et la partie d'extrémité de la conduite 18 est prolongée par la partie débouchante 21 comportant le ressort 23 également parallèle au sens d'écoulement du fluide dans la tubulure 6a et maintenant l'organe formant clapet 20 en position de fermeture contre son siège d'étanchéité 22 qui est ainsi situé en aval du dispositif thermostat 19.As shown in Figures 2 and 3, the valve member 20 is disposed in a downstream end portion of the pipe 18 preferably opening, when the valve member 20 is open, downstream of the valve of the thermostat device 19 According to FIG. 2, the arrival of the fluid coming from the expansion tank 16 is located upstream of the thermostat device 19 and the end of the pipe 18 is extended by a through part 21 in which the sealing seat is located. 22 of the valve member 20 which is held in the closed position in abutment against the seat 22 downstream of this seat by a prestressed spring 23 disposed in the end portion of the through part parallel to the direction of flow of the fluid in the tubing inlet 6a of the pump 6. According to FIG. 3, the arrival of the fluid coming from the expansion tank 16 is located downstream of the thermostat device 19 and the end part of the pipe 18 is extended by the through part 21 comprising the spring 23 also parallel to the direction of flow of the fluid in the tube 6a and maintaining the valve member 20 in the closed position against its sealing seat 22 which is thus located downstream of the thermostat device 19.

La figure 4 représente de façon détaillée un mode de réalisation particulier de l'agencement correspondant à celui représenté en figure 2. La partie d'extrémité aval de la conduite 7 comporte un renflement 7a dans lequel est définie la partie débouchante 21 en forme de chambre annulaire disposée coaxialement à l'axe longitudinal de la tubulure d'entrée 6a et en communication de fuide avec la conduite 18 par l'intermédiaire d'une ouverture radiale 7b réalisée dans le renflement 7a et débouchant extérieurement, l'extrémité aval de la conduite 18 pouvant être emmanchée dans l'orifice 7b. La chambre annulaire 21 comporte ainsi une partie en forme de dôme définissant une paroi annulaire interne 7c de la conduite 7 et une paroi annulaire externe 7d de raccordement à la tubulure 6a. A l'extrémité libre de la paroi annulaire 7c, est définie une ouverture tronconique contre laquelle vient en appui, par l'intermédiaire d'un joint d'étanchéité J1, une portion de la partie supérieure en tronc de cône 24a du corps 24 du dispositif thermostat 19. La partie 24a est surmontée d'une structure supérieure terminale à trois nervures 24b disposées à 120 degrés les unes par rapport aux autres et convergeant dans la conduite 7 en une partie centrale commune en forme de capuchon 25 à laquelle elles se raccordent. La face supérieure de la partie tronconique 24a comporte trois orifices 24a1 autorisant le passage de fluide dans la conduite 7 vers la tubulure d'entrée 6a lorsque la soupape 26 du dispositif thermostat 19 est dégagée de son siège d'étanchéité formé dans la partie tronconique 24a juste en aval des orifices 24a1. Le dispositif thermostat 19 est du type à capsule thermostatique 27, connu en soi , en forme de corps généralement cylindrique disposé coaxialement à la tubulure 6a tout en s'étendant de part et d'autre du plan de raccordement de la conduite 7 à la tubulure 6a. La capsule se termine à sa partie supérieure par rapport à la figure 4 par une tige 27a dont l'extrémité libre prend appui sur le capuchon 25 et sur laquelle le corps de la capsule est susceptible de se déplacer coaxialement à l'axe longitudinal de la tubulure 6a. La soupape 26 est constituée d'une plaque métallique en forme de rondelle 26a coaxiale à l'axe longitudinal de la tubulure 6a et solidaire du corps de la capsule 27. La partie d'extrémité circulaire de la plaque 26a est noyée dans un joint d'étanchéité 26b dont la partie externe assurant l'obturation étanche des orifices 24a1 est de forme tronconique. Le corps 24 comporte une paroi cylindrique 24c se raccordant à la paroi tronconique 24a par l'intermédiaire d'un paroi plane annulaire 24d perpendiculaire à la paroi 24c. La paroi 24c se termine par un rebord annulaire externe 24e noyé dans un joint d'étanchéité annulaire 28 entre la conduite 7 et la tubulure 6a. Le corps 24 comporte de plus en sa partie inférieure trois branches 24f, dont une seule est représentée en figure 4, et disposées à 120 degrés les unes des autres. Chaque branche se termine par une partie en forme de coupelle 24f1 contre laquelle vient en appui la spire extrême d'un ressort précontraint 29 dont la spire extrême opposée est en appui dans le joint 26b de façon à maintenir le joint 26b en appui pressé contre le siège d'étanchéité de la soupape 26 en position de fermeture de celle-ci.Figure 4 shows in detail a particular embodiment of the arrangement corresponding to that shown in Figure 2. The downstream end portion of the pipe 7 has a bulge 7a in which is defined the through portion 21 in the form of chamber annular arranged coaxially to the longitudinal axis of the inlet pipe 6a and in fluid communication with the pipe 18 by means of a radial opening 7b produced in the bulge 7a and opening outwardly, the downstream end of the pipe 18 can be fitted into the orifice 7b. The annular chamber 21 thus comprises a dome-shaped part defining an internal annular wall 7c of the pipe 7 and an external annular wall 7d for connection to the pipe 6a. At the free end of the annular wall 7c, a frustoconical opening is defined against which abuts, by means of a seal J1, a portion of the upper part in frusto-cone 24a of the body 24 of the thermostat device 19. Part 24a is surmounted by an upper terminal structure with three ribs 24b arranged at 120 degrees relative to each other and converging in line 7 into a common central part in the form of a cap 25 to which they are connected . The upper face of the frusto-conical part 24a has three orifices 24a1 allowing the passage of fluid in the pipe 7 towards the inlet pipe 6a when the valve 26 of the thermostat device 19 is released from its sealing seat formed in the frusto-conical part 24a just downstream from holes 24a1. The thermostat device 19 is of the thermostatic capsule 27 type, known per se, in the form of a generally cylindrical body arranged coaxially with the pipe 6a while extending on either side of the connection plane of the pipe 7 to the pipe. 6a. The capsule ends at its upper part with respect to FIG. 4 by a rod 27a, the free end of which bears on the cap 25 and on which the body of the capsule is capable of moving coaxially with the longitudinal axis of the tubing 6a. The valve 26 consists of a metal plate in the form of a washer 26a coaxial with the longitudinal axis of the tube 6a and integral with the body of the capsule 27. The circular end part of the plate 26a is embedded in a joint d sealing 26b, the external part of which ensuring the tight sealing of the orifices 24a1 is of frustoconical shape. The body 24 has a cylindrical wall 24c connecting to the frustoconical wall 24a by means of an annular plane wall 24d perpendicular to the wall 24c. The wall 24c ends in an external annular rim 24e embedded in an annular seal 28 between the pipe 7 and the pipe 6a. The body 24 further comprises in its lower part three branches 24f, only one of which is shown in Figure 4, and arranged at 120 degrees from each other. Each branch ends in a cup-shaped part 24f1 against which the end turn of a pre-stressed spring 29 bears, the opposite end turn of which rests in the seal 26b so as to keep the seal 26b in pressure pressed against the valve sealing seat 26 in the closed position thereof.

Avantageusement, la paroi annulaire 24d comporte des orifices 24d1 pour le passage du fluide dans la conduite 18 vers la tubulure 6a et fait office de siège d'étanchéité pour l'organe formant clapet 20 en forme d'anneau plat entourant coaxialement le ressort 29. On comprend ainsi que le siège d'étanchéité de la soupape 26 et le siège d'étanchéité de l'organe formant clapet sont réalisés en une seule pièce. Pour assurer la fermeture étanche des orifices 24d1, l'organe formant clapet 20 comporte sur sa face supérieure un joint annulaire d'étanchéité 30. De plus, l'organe formant clapet 20 est disposé dans un corps 31 d'une manière générale en forme de bague cylindrique intégrée dans la paroi cylindrique 24c en étant solidarisée à celle-ci. Le corps 31 comporte un rebord inférieur de retenue du ressort 23 monté ainsi précontraint entre ce rebord et l'organe formant clapet 20, parallèlement au ressort 29. L'organe formant clapet 20 est situé en aval du siège d'étanchéité de la soupape 26.Advantageously, the annular wall 24d has orifices 24d1 for the passage of the fluid in the pipe 18 towards the tube 6a and acts as a sealing seat for the valve-forming member 20 in the form flat ring coaxially surrounding the spring 29. It is thus understood that the sealing seat of the valve 26 and the sealing seat of the valve member are made in one piece. To ensure the watertight closure of the orifices 24d1, the valve member 20 has on its upper face an annular sealing gasket 30. In addition, the valve member 20 is disposed in a body 31 generally in shape of cylindrical ring integrated in the cylindrical wall 24c while being integral with the latter. The body 31 has a lower spring retaining rim 23 mounted in this way prestressed between this rim and the valve member 20, parallel to the spring 29. The valve member 20 is located downstream of the valve sealing seat 26 .

Le principe de fonctionnement de l'agencement décrit en figure 4 et utilisé dans le circuit de la figure 1 va être maintenant expliqué.The operating principle of the arrangement described in FIG. 4 and used in the circuit of FIG. 1 will now be explained.

Lors du démarrage à froid du moteur, la soupape 26 du dispositif thermostat 19 est fermée de sorte que les circuits de passage du fluide comprenant respectivement la conduite 4, le radiateur 5, la conduite 7 et la conduite 14, l'échangeur 13, la conduite 15 sont hors service. A faibles vitesses ou faibles régimes du moteur, peu de dépression se produit en amont de la pompe 6 ou dans la tubulure 6a, l'organe formant clapet reste fermé et le circuit de fluide comprenant la conduite 17, le vase d'expansion 16 et la conduite 18 est hors service. De la sorte, il se produit une montée rapide en température dans le moteur et dans l'échangeur 11. Quand la vitesse ou le régime du moteur atteint et dépasse une valeur prédéterminée, par exemple de 2500 tours par minute, la dépression à l'entrée de la pompe atteint une valeur de seuil donnée légèrement inférieure à la dépression provoquant la cavitation du fuide. Alors, l'organe formant clapet 20 s'ouvre, le ressort 23 étant taré en correspondance à la valeur de seuil, et met en communication le circuit additionnel de fluide formé par la conduite 17, le vase d'expansion 16 et la conduite 18, en plus du by-pass permanent 9 et du circuit conduite 10, échangeur 11, conduite 12, avec la tubulure d'entrée 6a de la pompe 6. On obtient ainsi les courbes de pression d'entrée A et de sortie B de fluide à la pompe 6 représentées en pointillés à la figure 6 pour éviter la cavitation du fluide. Les deux courbes en traits pleins A′ et B′ représentent respectivement les pressions d'entrée et de sortie de la pompe avec un dispositif thermostat conventionnel. On constate ainsi que pour un débit d d'entrée de fluide de 100 litres par minute à la pompe 6, correspondant par exemple à une vitesse de rotation du moteur d'environ 2500 tours par minute, l'organe formant clapet 20 s'ouvre pour une dépression d'environ 200 millibars et au-delà de ce régime moteur, la dépression est sensiblement stabilisée à cette valeur (courbe A). Par le dispositif thermostat traditionnel, la cavitation du fluide se produit à un débit de fluide à l'entrée de la pompe d'environ 150 litres par minute correspondant à un régime moteur d'environ 3000 tours par minute (courbe A′). Bien entendu, quand la température du fluide dans la conduite 7 atteint une valeur de seuil, par exemple de 80°C, le corps 27 s'abaisse avec la soupape 26, autorisant ainsi 30 l'écoulement du fluide dans la conduite 7 vers la tubulure 6a à travers les orifices 24a1.During the cold start of the engine, the valve 26 of the thermostat device 19 is closed so that the fluid passage circuits comprising respectively the line 4, the radiator 5, the line 7 and the line 14, the exchanger 13, the line 15 is out of service. At low speeds or low engine speeds, little vacuum occurs upstream of the pump 6 or in the pipe 6a, the valve member remains closed and the fluid circuit comprising the line 17, the expansion tank 16 and line 18 is out of service. In this way, there is a rapid rise in temperature in the engine and in the exchanger 11. When the speed or the engine speed reaches and exceeds a predetermined value, for example of 2500 revolutions per minute, the vacuum at pump inlet reaches a given threshold value slightly lower than the depression causing the fluid to cavitate. Then, the valve member 20 opens, the spring 23 being calibrated in correspondence with the threshold value, and puts in communication the additional fluid circuit formed by the pipe 17, the expansion tank 16 and the pipe 18 , in addition to the permanent bypass 9 and the pipe circuit 10, exchanger 11, pipe 12, with the inlet manifold 6a of the pump 6. This gives the inlet pressure A and outlet B fluid pressure curves. to the pump 6 shown in dotted lines in Figure 6 to avoid cavitation of the fluid. The two curves in solid lines A ′ and B ′ represent respectively the inlet and outlet pressures of the pump with a conventional thermostat device. It can thus be seen that for a fluid inlet flow rate of 100 liters per minute to the pump 6, corresponding for example to a motor rotation speed of around 2500 revolutions per minute, the valve member 20 opens for a depression of around 200 millibars and beyond this engine speed, the depression is substantially stabilized at this value (curve A). By the traditional thermostat device, the cavitation of the fluid occurs at a fluid flow rate at the inlet of the pump of approximately 150 liters per minute corresponding to an engine speed of approximately 3000 revolutions per minute (curve A ′). Of course, when the temperature of the fluid in the pipe 7 reaches a threshold value, for example of 80 ° C., the body 27 is lowered with the valve 26, thus authorizing the flow of the fluid in the pipe 7 towards the tubing 6a through the orifices 24a1.

Claims (1)

1. Circuit for the cooling by a liquid such as water of an internal combustion engine (1) of an automotive vehicle, of the type comprising a pump (6) having an outlet connected by a duct (8) to the engine (1) and an inlet (6a) connected on the one hand to a radiator (5) for the cooling of the liquid by a duct (7) the downstream end of which comprises a thermostat (19) with a valve (26) kept bearing against its sealing seat by a prestressed spring (29) and the opening of which takes place when the temperature of the fluid reaches a predetermined upper threshold value and on the other hand to an expansion chamber (16) by another duct (18) comprising a valve member (20) maintained against its sealing seat by a prestressed spring (23) and the opening of which provides for the flow of a fluid only in the direction from the expansion chamber (16) towards the pump (6), the downstream end portion of the other duct (18) opening downstream of the valve (26) of the thermostat (19) and the valve member (20) being disposed at one of the ends of the duct (18) directly connecting the expansion chamber (16) to the inlet (6a) of the pump (6) and opening to allow the flow of liquid from the expansion chamber (16) towards the pump (6) when the depression at the inlet of the pump (6) reaches a threshold value slightly lower than a depression value producing a cavitation of the liquid, characterized in that the valve member (20) is disposed at the downstream end (21) of the duct (18), is accommodated with the prestressed spring (23) adjusted to the threshold value in a body (31) integrated into the body (24) of the thermostat (19) in such a manner that the spring (23) for holding the member (20) be parallel to the spring (29) for holding the valve (26) is located in an annular chamber formed in a bulge (7a) of the downstream end of the duct (7) connecting the radiator (5) to the pump (6) and is in the shape of a flat ring coaxially surrounding the holding spring (29) and in that the sealing seat of the valve member (20) and the sealing seat of the thermostat valve (26) are formed in the body (24) of the thermostat (19).
EP19890403089 1988-11-28 1989-11-08 Cooling circuit for an internal-combustion engine of a motor vehicle Expired - Lifetime EP0371841B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8815530 1988-11-28
FR8815530A FR2639675B1 (en) 1988-11-28 1988-11-28 COOLING CIRCUIT OF AN INTERNAL COMBUSTION ENGINE OF A MOTOR VEHICLE

Publications (2)

Publication Number Publication Date
EP0371841A1 EP0371841A1 (en) 1990-06-06
EP0371841B1 true EP0371841B1 (en) 1992-07-08

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ID=9372326

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19890403089 Expired - Lifetime EP0371841B1 (en) 1988-11-28 1989-11-08 Cooling circuit for an internal-combustion engine of a motor vehicle

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EP (1) EP0371841B1 (en)
DE (1) DE68902043T2 (en)
FR (1) FR2639675B1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2702244B1 (en) * 1993-03-01 1995-04-21 Peugeot Cooling device for an internal combustion engine.

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2408722A1 (en) * 1977-11-10 1979-06-08 Berliet Automobiles ADVANCED COOLING CIRCUIT FOR AN INTERNAL COMBUSTION ENGINE
DE3143749A1 (en) * 1981-11-04 1983-05-11 Magirus-Deutz Ag, 7900 Ulm Device for safeguarding the water pressure in the cooling water circuit of an internal combustion engine
US4461342A (en) * 1982-04-29 1984-07-24 Avrea Walter C Method and apparatus for automatically refilling a leaking liquid cooling system as an engine operates by utilizing a radiator and a remote coolant reservoir
DE3226508C2 (en) * 1982-07-15 1985-12-12 Bayerische Motoren Werke AG, 8000 München Cooling circuit for internal combustion engines
DE3718697C2 (en) * 1986-06-14 1997-06-19 Volkswagen Ag Cooling arrangement for an internal combustion engine of a vehicle

Also Published As

Publication number Publication date
DE68902043D1 (en) 1992-08-13
FR2639675A1 (en) 1990-06-01
DE68902043T2 (en) 1993-03-04
FR2639675B1 (en) 1991-03-22
EP0371841A1 (en) 1990-06-06

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