EP0374038B1 - Cooling device for an internal-combustion engine - Google Patents

Description

The cooling circuit of an internal combustion engine must necessarily include a degassing device because one cannot ensure an absolute seal between the interior of the cylinders and the water chambers. You can degas the engine itself. However, the volume of liquid to be heated is then significantly increased as soon as the engine is started because this involves heating the liquid contained in the expansion tank as soon as it is started; the temperature rise of this engine and of its cooling circuit is therefore delayed, which increases external pollution due to the prolonged use of cold enrichment systems and, consequently, also increases fuel consumption and, in the case of a vehicle engine, interferes with heating of the vehicle interior.

You can also degas the radiator. However, always with the aim of quickly reaching normal operating temperatures, the coolant is not circulated in the radiator as soon as the engine is started. One can for example use a thermostatic valve which prevents the circulation of the liquid when the temperature of this one is lower than a given value. This circulation is therefore only established after the start-up period and degassing only takes place at this time, which is a drawback.

French Patent 2,317,489 describes a liquid cooling device for an internal combustion engine which provides degassing of the cooling circuit as soon as the engine is started while minimizing the volume of the coolant to be heated after this start-up. market. This cooling device comprises a main cooling circuit comprising a radiator connected to the engine by a liquid inlet pipe and a return pipe, means for circulating the liquid between the engine and the radiator, and a thermostatic valve suitable for interrupt the circulation of the liquid when the temperature thereof is below a given value, a secondary cooling circuit mounted in parallel with the main circuit and comprising a low-volume degassing chamber connected to the engine by a liquid inlet pipe and a departure excluding any valve so that liquid circulates permanently in this secondary circuit, and means for circulating the liquid between the engine and the degassing chamber, and an expansion tank connected to one of the cooling circuits. Patent EP-A-0 250 734 describes a cooling device, the degassing chamber of which is located on the return line from the radiator to the engine, immediately upstream of the suction pump, tapering from its lower part to its upper part, and communicates at its upper part with the expansion tank via a small diameter pipe fitted with a non-return valve.

The present invention relates to a cooling device characterized in that the flow line from the degassing chamber opens into the return line of the main circuit, the expansion tank being connected directly to the main cooling circuit and in that one of the walls of the degassing chamber has an orifice connected to the expansion tank by means of a valve arranged to open when gas is present in the chamber.

In an advantageous embodiment of the invention, the degassing chamber is arranged under the expansion vessel and the orifice allows direct communication between the upper part of the degassing chamber and the lower part of the expansion vessel.

• La Figure 1 est le schéma de ce dispositif de refroidissement;
• La Figure 2 est une vue en coupe de la chambre de dégazage suivant II-II de la Figure 1;
• La Figure 3 montre un autre mode de réalisation du clapet;
• La Figure 4 montre un troisième mode de réalisation du clapet;
• La Figure 5 montre un quatrième mode de réalisation du clapet;
• La Figure 6 est une vue schématique illustrant une réalisation dans laquelle la chambre de dégazage est éloignée du vase d'expansion et reliée à celui-ci par un conduit.

Various embodiments of the device according to the invention have been described below, by way of non-limiting example, with reference to the appended drawings in which:

• Figure 1 is the diagram of this cooling device;
• Figure 2 is a sectional view of the degassing chamber along II-II of Figure 1;
• Figure 3 shows another embodiment of the valve;
• Figure 4 shows a third embodiment of the valve;
• Figure 5 shows a fourth embodiment of the valve;
• Figure 6 is a schematic view illustrating an embodiment in which the degassing chamber is remote from the expansion tank and connected thereto by a conduit.

In FIG. 1, an internal combustion engine 1 is seen which comprises a main cooling circuit comprising a pump 2.

• Un circuit principal qui comprend un radiateur 4 relié au moteur 1 par un conduit d'arrivée 5 et un conduit de retour 3. Ce circuit comporte un clapet ou une vanne thermostatique 6 qui est fermé lorsque la température du liquide de refroidissement est inférieure à une valeur donnée. Le conduit de retour 3 est relié, par l'intermédiaire d'un conduit 7, à la partie inférieure d'un vase d'expansion 8. Ce dernier est fermé à sa partie supérieure par un bouchon taré 9 et il est relié à un dispositif de dégazage 10 du radiateur 4.
• Deux circuits secondaires dans lesquels le liquide circule en permanence :
  • a) un circuit utilisé pour le chauffage de l'habitacle et comprenant un échangeur de chaleur 11 relié au moteur par un conduit d'alimentation 13 et un conduit de retour 12;
  • b) un circuit servant au réchauffage des organes annexes 16 tels que starter, circuit de ralenti, etc... ainsi qu'au dégazage du moteur. Il est constitué des conduits 15,17,18 et d'une chambre de dégazage 14. Le liquide sortant du moteur passe successivement dans le conduit 15, le ou les organes 16, le conduit 17, la chambre 14 et retourne à l'aspiration de la pompe 2 par le conduit 18.

The liquid circulates through the engine and leaves it by several circuits, namely:

• A main circuit which comprises a radiator 4 connected to the engine 1 by an inlet duct 5 and a return duct 3. This circuit comprises a valve or a thermostatic valve 6 which is closed when the temperature of the coolant is below a given value. The return conduit 3 is connected, via a conduit 7, to the lower part of an expansion vessel 8. The latter is closed at its upper part by a tared plug 9 and it is connected to a degassing device 10 of the radiator 4.
• Two secondary circuits in which the liquid circulates permanently:
  • a) a circuit used for heating the passenger compartment and comprising a heat exchanger 11 connected to the engine by a supply duct 13 and a return duct 12;
  • b) a circuit used for heating the additional members 16 such as a choke, an idling circuit, etc., as well as for degassing the engine. It consists of the conduits 15, 17, 18 and a degassing chamber 14. The liquid leaving the engine passes successively through the conduit 15, the member (s) 16, the conduit 17, the chamber 14 and returns to the suction pump 2 through line 18.

As seen in Figure 2, the degassing chamber 14 has a circular section and the conduits 17 and 18 are of small section, less than that of the conduits 3 and 5, and open tangentially.

The degassing chamber 14 is disposed under the expansion vessel 8 and adjoined to it by its upper part, the upper wall of the chamber constituting a part of the lower wall 19 of the vessel; it has a small section orifice 20 through which it can communicate directly with the expansion tank and which can be closed by a valve 21. The apparent density of this valve is slightly less than or equal to the density of the coolant. It is connected at its upper part by an arm 22 to retaining arms 23 which limit its downward stroke by abutting against the partition 19.

It would not, however, depart from the scope of the invention using the configuration of Figure 6 in which the chamber 14 is remote from the expansion tank 8. In this case, the arms 23 of the valve 21 are located in a communicating chamber 28 with the degassing chamber 14 through the orifice 20, the chamber 28 being in communication with the expansion tank 8 by a conduit 29. This makes it possible to mount the device of the invention on a cooling system of a vehicle already existing.

When the cold engine starts, the valve 6 is closed, so that there is no circulation in the radiator 4. The only liquid which passes through the expansion tank 8 is that which reaches it through the orifice 20 Given the small dimensions of this orifice and the small section of the pipe 17, the pressure P in the expansion tank 8 is practically identical to the suction pressure. On the other hand, the pressure P ′ in the chamber 14 is intermediate between the pressure in the engine before the valve 6, itself close to the discharge pressure of the pump 2, and the suction pressure of this pump. The pressure P ′ in the chamber 14 is therefore greater than the pressure P in the expansion tank. Under the effect of the pressure difference (P ′ - P) and the Archimedes' thrust due to its density slightly lower than that of the liquid, the valve 21 comes to apply on its seat practically as soon as the engine.

p étant le poids du flotteur diminué de la poussée d'Archimède et s la section de l'orifice 20.When gas has accumulated in the chamber 14, it concentrates in the zone where the valve 21 is located due to the rotation of the liquid in this chamber. Archimedes' thrust on valve 21 decreases and it opens as soon as the following inequality is verified:

${\text{p> (P ′ - P)}}^{\text{s}}$

p being the weight of the float less the buoyancy and s the section of the orifice 20.

If this inequality is not verified in a certain embodiment, it is possible to increase the volume of the valve, therefore its weight, to decrease the section s or the difference P ′ - P, this reduction being able to be obtained by modifying the internal dimensions of the conduits 15 , 17 and 18, by increasing the pressure drops upstream of the chamber 14, for example by providing a diaphragm on one of the conduits 15 and 17, or by reducing the pressure drop P ′ - P.

In Figures 1 and 2, the valve 21 is constituted by a spherical body, which can be retained by the arms 23 of which it is integral and the orifice 20 is formed in a flat part of the partition 19. But in the embodiment of Figure 3, the orifice 20 is formed in a spherical portion 19 a of the partition 19 and the seal 21 is retained by arms 24 integral with the partition. A tranquilization grid 25 can optionally be provided under the valve.

In the embodiment of Figure 4, the valve is constituted by a cylindrical mass 26 which carries at its upper part a finger 27 adapted to close the orifice 20 which is formed in a frustoconical part or spherical 19 b of the partition 19. The mass 26 is guided and retained by the arms 24 secured to the partition 19. The tranquilization grid 25 attached to the arms 24 is also provided in this embodiment.

Figure 5 illustrates an embodiment similar to that of Figure 4. As before, the valve 30 is movable in a space limited by a frustoconical or spherical part 19 c of the wall 19, the arms 24 and the tranquilization grid 25 It consists of a body 31 extended by an upper part 32 and a lower part 33 of smaller dimensions. The part 32 carries the finger 27 and it is guided by centering arms 34. The lower part 33 is in the shape of a cross and it passes through an orifice 35 of the grid 25. The lower face of the body 31 has a part 36 in the shape of a truncated cone to avoid accidental sticking to the grid 25.

Claims (12)

1. Device for the liquid cooling of an internal combustion engine which comprises one main cooling circuit including a radiator (4) connected to the engine (1) by a liquid intake pipe (5) and one return pipe (3), means (2) to make the liquid circulate between the engine (1) and the radiator (4), and a thermostatic valve (6) able to interrupt circulation of the liquid when the temperature of the latter is less than a given value, at least one secondary circuit mounted in parallel with the main circuit and including one degassing chamber (14) with a small volume connected to the engine (1) via a liquid intake pipe (17) and one original pipe (18) excluding any valve so that the liquid circulates continuously in this secondary circuit, and means (2) to make the liquid circulate between the engine (1) and the degassing chamber (14), and an expansion chamber (8) connected to one of the cooling circuits, wherein the original pipe (18) of the degassing chamber (14) opens into the return pipe (3) of the main circuit, the expansion chamber (8) being connected directly to the main cooling circuit and wherein one (19) of the walls of the degassing chamber (14) comprise an orifice (20) connected to the expansion chamber (8) by means of a valve (21 or 26) disposed in such a way as to open when the gas is present in the chamber (14).
2. Cooling device according to claim 1,
   wherein the degassing chamber (14) is disposed under the expansion chamber (8) and wherein the orifice (20) allows for direct communication between the upper portion of the degassing chamber (14) and the lower portion of the expansion chamber (8).
3. Cooling device according to claim 1,
   wherein the degassing chamber (14) is distanced from the expansion chamber (8), said orifice (20) being connected to the latter by a pipe (29).
4. Cooling device according to any one of claims 1 to 3,
   wherein the degassing chamber (14) has a circular section and wherein the inlet (17) and outlet (18) pipes open into it tangentially.
5. Cooling device according to any one of claims 1 to 4,
   wherein the valve (21, 26 or 30) has a density at the most equal to that of the cooling liquid.
6. Cooling device according to any one of the preceding claims,
   wherein the pipes (17 and 18) connecting the degassing chamber (14) to the engine (1) have a section smaller than that of the pipes (3 and 5) connecting the radiator (4) to the engine (1).
7. Cooling device according to any one of the preceding claims,
   wherein the valve (21) comprises at its upper portion retaining arms (23) which limit its travel towards the bottom by abutting against the partition (19) of the chamber (14).
8. Cooling device according to any one of claims 1 to 6,
   characterized by retaining arms (24) integral with the wall (19) and limiting the travel of the valve (21) towards the bottom.
9. Cooling device according to any one of the preceding claims,
   wherein the valve (21) is spherical.
10. Cooling device according to any one of the preceding claims,
    wherein the orifice (20) is fitted in one flat portion of the wall (19).
11. Cooling device according to any one of claims 1 to 9,
    wherein the orifice (20) is disposed in one spherical portion (19a) of the wall (19).
12. Cooling device according to any one of claims 1 to 8,
    wherein the valve (26) is constituted by a cylindrical weight bearing at its upper portion a finger able to seal off the orifice (20) disposed in a truncated portion (19b) of the partition (19).

Images