Abstract:
The circuit includes an internal volume for receiving a cooling fluid, a stopper for selectively closing an opening giving access to the internal volume, and ensuring element that the cooling fluid can be discharged via a discharge outlet. The respective discharge and access openings to the internal volume are distinct from each other, and a flap valve, which is detachably fixed in relation to the stopper and which is moveable between respective closure and release positions of the access opening when the flap valve is disconnected from the stopper, is also provided. The flap valve exclusively moves from its closed position when the pressure prevailing inside the internal volume is lower than a predefined pressure value.

Description:
RELATED APPLICATIONS 
   The present application is based on International Application No. PCT/FR2004/000456 filed Feb. 27, 2004, and claims priority from, French Application No. 03 02417filed Feb. 27, 2003, the disclosure of which is hereby incorporated by reference herein in its entirety. 
   FIELD OF THE INVENTION 
   The present invention relates to a cooling circuit for a motor vehicle, as well as to a motor vehicle provided with such a cooling circuit. 
   A cooling circuit conventionally comprises different pipes, also called hose connections, which extend in the vicinity of the motor and the radiator of the motor vehicle. In addition, a member allowing selective access to the internal volume of this circuit is provided, in order that a user may periodically proceed with an addition of cooling liquid. 
   BACKGROUND OF THE INVENTION 
   It is known to make the afore-mentioned member in the form of a stopper, which is mobile between respective positions of closure and of access to this internal volume. To that end, the stopper is fixed on the body of the cooling circuit, for example by screwing or by means of a rapid fixation, of the “quarter-turn” type. 
   In addition, this stopper is provided with a flap valve allowing discharge of air and of water, out of the cooling circuit, when the pressure of cooling liquid attains an abnormally high value, particularly in the case of overheating. It also comprises an additional flap valve allowing the admission of air, by depression, in the cooling circuit. 
   However, this known solution involves certain drawbacks, in particular in terms of safety for the user. 
   In effect, the afore-mentioned stopper proves to be particularly dangerous for the driver, when he/she proceeds with opening the stopper, while the cooling liquid is still at a high temperature. There is in that case a considerable risk of projection of hot liquid, which is expelled from the cooling circuit in the direction of the driver, under the effect of the pressure. 
   This being specified, the invention proposes to produce a cooling circuit allowing the different drawbacks of the prior art set forth hereinabove to be overcome. 
   To that end, it has for its object -a cooling circuit for motor vehicle, particularly for motor vehicle with internal combustion, presenting a body comprising at least one pipe intended to extend in the vicinity of the motor and of the radiator of said vehicle, this body presenting an internal volume for receiving a cooling fluid, this circuit also comprising a stopper for selectively closing an opening giving access to this internal volume, this stopper being removably fixed on the body, as well as means ensuring discharge of said cooling fluid, particularly in the case of over-pressure, via a discharge outlet, characterized in that the respective openings for discharge and for access to the internal volume are distinct and in that a flap valve is provided, removably fixed on the stopper, this flap valve being mobile, when it is disconnected with respect to the stopper, between respective closure and release positions of the access opening, this flap valve being adapted to leave its position of closure only when the pressure prevailing in the internal volume becomes lower than a predetermined pressure. 
   SUMMARY OF THE INVENTION 
   According to other characteristics of the invention:
         the predetermined pressure is close to the atmospheric pressure, in particular slightly higher than the latter.   the body of the cooling circuit comprises means for supporting the valve, in its position of release.   the body of the cooling circuit comprises abutment means, adapted to oppose a movement of translation of the flap valve, in particular upward, so as to disconnect this valve with respect to the stopper.   the stopper comprises a body adapted to be connected, particularly by screwing, on the body of the cooling circuit, as well as a shell for a user to grip, which is disengageable with respect to the body of the stopper.   the stopper is provided with a skirt, adapted to be introduced inside a neck of the cooling circuit, sealing means being imprisoned between the opposite walls of this skirt and this neck.   the means for removably fixing the flap valve on the stopper are means for fixation by elastic clipping, particularly a stud belonging to the stopper, adapted to be fixed by elastic clipping in a bottom of the valve.   the discharge means comprise a discharge valve adapted to close the discharge outlet selectively.   the discharge outlet is adapted to direct the cooling fluid expelled from said internal volume substantially downwardly.   an orifice is in addition provided, for placing the internal volume at atmospheric pressure, which is distinct from the discharge outlet and the access opening.   the body of the cooling circuit comprises an expansion tank, the access opening being provided in the upper part of this expansion tank, while the discharge outlet is provided below this expansion tank.   the orifice for placing at atmospheric pressure is provided at the apex of the expansion tank, next to the access opening.       

   The invention also has for its object a motor vehicle, particularly with internal combustion, which is provided with a cooling circuit as defined hereinabove. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     The invention will be described hereinafter with reference to the accompanying drawings, given solely by way of non-limiting example, in which: 
       FIG. 1  is a view in longitudinal section of a cooling circuit according to the invention. 
       FIG. 2  is a view in section, on a larger scale, illustrating in isolated manner the stopper of the cooling circuit of  FIG. 1 , in a position of normal service. 
       FIG. 3  is a view in section, on a larger scale, illustrating in isolated manner means for admission of air, by depression, with which the cooling circuit of  FIG. 1  is provided. 
       FIG. 4  is a view in section, similar to  FIG. 2 , partially illustrating the cooling circuit, after its stopper has been removed; and 
       FIG. 5  is a view in section, on a larger scale, illustrating in isolated manner discharge means with which the cooling circuit of  FIG. 1  is provided. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The cooling circuit, partially illustrated in  FIG. 1 , conventionally comprises a plurality of pipes, or hose connection, of which only one is shown in this  FIG. 1 , where it is given reference  2 . These different hose connections conventionally extend in the vicinity of the engine and of the radiator of a motor vehicle, which have not been shown. 
   A connection  4 , coaxial to the hose connection  2 , is inserted at the end of this latter. It has a lateral outlet  6  made therein, intended for the discharge of the fluid admitted in the cooling circuit, as will be seen hereinafter. 
   This outlet  6  opens out in a housing  8 , within which a flap valve  10  is received, adapted to selectively close the afore-mentioned outlet  6 . This flap valve is mounted against a spring  12 , abutting by one of its ends against a stopper  14 , which has an orifice  16  made therein allowing the housing  8  to be placed in communication with the atmosphere. 
   It should be noted that the housing  8  extends obliquely, globally downwardly. Consequently, as will be seen more precisely in the following, this makes it possible to give the fluid possibly escaping from the cooling circuit a descending direction. 
   The hose connection  2  is connected to an expansion tank  18 , of type known per se, which presents a vertical major axis, denoted A. This tank  18  is divided, in its upper part, into a principal chamber  20  and a peripheral chamber  22 , which are separated by a vertical annular wall  24 . 
   At its upper end, opposite the hose connection  2 , the expansion tank  18  is provided with a threaded neck  26 . Moreover, in the vicinity of the walls of this neck, a re-entrant peripheral flange  28  is provided, defining an opening  30  allowing access to the internal volume V of the expansion tank. 
   The expansion tank  18  is in addition capped by a stopper, generally designated by reference  32 . The latter comprises a tapped body  34 , intended to cooperate with the threaded neck  26 , as well as an outer shell  36  ensuring grip by a user. 
   The body  34  and the shell  36  are such that they give the screwing of the stopper  32  on the neck  26  a disengageable character. This means that, prior to the movement of rotation allowing unscrewing of the stopper, the user must proceed with a complementary movement, in the present case press downwardly on the shell  36 . 
   This disengageable character, of type known per se, may, however, be assured differently, in particular by providing that the user must pinch the shell  36  against the body  34 , before proceeding with the afore-mentioned unscrewing. 
   The stopper  32  is provided with a skirt  38 , presenting a closed bottom  40 , which is provided with a stud  42 , whose function will be explained in the following. An O-ring  44  is, furthermore, imprisoned between the opposite faces of the neck  26  and of the skirt  38 . 
   A flap valve  46  is also provided, comprising a web  48 , extended by a lateral wall  50 , which is itself terminated by an outer flange  52 . This flap valve  46  is removably fixed to the stopper  32  by any appropriate means, in the present case by elastic clipping of the web  48  on the stud  42 . 
   The lateral wall  50  and the flange  52  of the flap valve  46  are received in a housing  54 , defined by an annular piece  56 , which is fixed on the body of the expansion tank, in the vicinity of the flange  28 . This annular piece  56  has a slot  58  made therein, allowing the internal volume V to be placed in communication with the access opening  30 . 
   The peripheral chamber  22  is placed in communication, at its upper end, with an opening  60  defined by a re-entrant flange  62 . Above the latter is provided a stopper  64 , having an orifice  66  made therein, intended for placing the internal volume V at atmospheric pressure, as will be seen hereinafter. 
   This stopper is equipped with a valve  68 , which selectively closes the orifice  66 . The latter is mounted against a spring  70 , of which one end abuts against the afore-mentioned flange  62 . 
     FIGS. 1 and 2  illustrate the cooling circuit in a state of normal functioning. In this configuration, the flap valve  10  obturates the discharge outlet  6 , while valve  68  obturates the orifice  66  for placing at atmospheric pressure and the principal stopper  32  is screwed on the neck  26 . 
   When the internal volume V of the expansion tank  18  is at a pressure clearly less than atmospheric pressure, the valve  68  tends to move away from its seat, formed on the stopper  64 . This then releases the orifice  66 , with the result that outside air can penetrate in the direction of the internal volume V, in the direction of arrows F 1  in  FIG. 3 , this inducing an increase in the internal pressure of the cooling circuit. 
   It should be noted that the presence of this valve  68  may also allow the filling of the cooling circuit by a professional, via the orifice  66 . This is advantageous, in terms of simplicity and rapidity, for the manufacturer who can fill the cooling circuit without removing the stopper  32 . 
   When the fluid admitted into the cooling circuit heats abnormally, the driver of the vehicle is warned, for example by the activation of a luminous signal. Such increase in temperature is accompanied by a corresponding rise in pressure of this fluid. 
   In the case of the user deciding to remove the stopper in order to add cooling liquid, he must firstly press downwardly on the shell  36 , before the operation of unscrewing proper. This therefore provides the cooling circuit of the invention with a first degree of safety. 
   Then, as this screwing takes place, the skirt  38  of the stopper  32  rises, opposite the body of the expansion tank  18 . At a certain moment of this movement, the flange  52  of the valve  46  comes into abutment against the flange  28 , provided on the expansion tank  18 , with the result that it is no longer shown in this Figure. 
   Consequently, if the user continues to unscrew the stopper, the valve  46  is disconnected from the skirt  38 , being given that its web  48  is no longer engaged with the stud  42 . This situation is thus illustrated in  FIG. 4 , where the stopper  32  is removed from the expansion tank  18 , so that it is no longer shown in this Figure. 
   In this figuration, if the pressure prevailing in the internal volume V remains high, the valve is maintained against the flange  28 , precisely under the effect of this pressure. This valve  46  therefore occupies a position of closure of the opening  30 , allowing access to the internal volume V. 
   On the other hand, when the internal pressure of the expansion tank redescends below a predetermined value, which is close to atmospheric pressure, in the present case slightly higher than the latter, the valve  46  tends to redescend under the effect of gravity (arrow F 2 ). It then resumes its position of  FIGS. 1 and 2 , which allows the user to access the internal volume V, for example with a view to adding cooling liquid. 
   At the end of its descending movement, the valve  46 , which henceforth occupies a position of release of the opening  30 , rests in abutment against the annular piece  56 . 
   It should be emphasized that the predetermined value of pressure below which the valve leaves its position of closure of the opening  30 , may be different from the one set forth hereinabove. Means, for example elastic ones, may thus be provided, which oppose the displacement of this valve in one or the other direction. 
   It should be noted that, being given that the valve leaves its position of closure only when the pressure redescends, this guarantees that the internal volume V is not accessible to the user in the event of too high a pressure. This therefore makes it possible to overcome any risk of projection of liquid in the direction of the user, which would be due to an excess pressure. 
   Furthermore, upon an abnormally high rise in pressure of the cooling liquid, the valve  10  is pushed opposite its seat, this releasing the discharge outlet  6 . Consequently, the overheated liquid is expelled from the cooling circuit via this outlet. 
   Being given the arrangement of the latter, this liquid is directed downwardly, for example towards the ground, in the direction of arrow F 3  in  FIG. 5 . Consequently, this phenomenon is not likely to be detrimental to the driver&#39;s physical integrity. 
   The invention is not limited to the example described and shown. 
   For example, the valve  68  for placing at atmospheric pressure can in particular be integrated in the stopper  32 . Moreover, the valve  10  may for example be provided on the body of the expansion tank  18 . 
   The invention makes it possible to attain the objects mentioned hereinabove. 
   For example, according to the invention, the respective outlets and openings for discharge and access to the internal volume are distinct. This therefore makes it possible to obturate the access opening by means of a stopper, this presenting a first degree of safety for the user. Furthermore, it is possible to arrange the discharge outlet so that the fluid possibly expelled from the cooling circuit is not directed towards the user. 
   Furthermore, the presence of the valve  46 , which allows access to the internal volume only when the pressure redescends to below a threshold value, gives an additional degree of safety to the cooling circuit of the invention. In effect, thanks to this measure, the user cannot proceed with an addition of cooling liquid when the internal pressure is capable of harming his physical integrity. 
   Finally, it should be noted that the principal stopper  32 , provided with a tapped body, may be adapted on already existent cooling circuits. This is particularly advantageous, in particular in terms of economy.