FR2766134A1 - Safety air inlet for vehicle fuel tank - Google Patents

Abstract

The safety air inlet has two valve seats (100,112) which are carried by an intermediate transverse wall of the housing (34) that forms the transverse wall. A lower chamber (62) is provided in which the first closure for the valve (72,78) is mounted so that it can move and is connected to the upper part of the fuel tank (12). An upper chamber (64) is also provided. The second closure element for the valve (120) is mounted in this so that it can move and it is connected to the air inlet line (28).

Description

 The present invention relates to a venting and safety device for a fuel tank of a motor vehicle.

 The invention relates more particularly to a device intended to equip a fuel tank of a motor vehicle, of the type comprising a venting duct which opens into a high point of the tank and into which is interposed a valve assembly provided with '' a counterweight which, in the event of at least partial overturning of the vehicle, closes a valve seat to prevent fuel from escaping from the tank through the venting pipe.

 It has already been proposed, in particular in document EP-A-0,254,631, such a valve in which the counterweight causes the valve to open when the vehicle is in the normal position.

 In this document, the valve also has the function of prohibiting overfilling of the tank, in particular by causing the valve to close when the fuel exceeds a certain level in the tank.

 To this end, the valve is provided with a float which, carried by the fuel, is capable of lifting the ball with its shutter in order to cause the valve to close. When the tank is half empty, the valve is open and consequently it lets out a certain flow of fuel vapor which evaporates.

In order to resolve some of the problems inherent in the design of the device proposed in this document, French patent application No. 2 740 402 has proposed a vent device of the type comprising a housing, one end of which lower is connected to the upper part of the fuel tank and the upper part of which is connected to a section of a vent pipe for venting the upper part of the tank, of the type comprising
- A first movable closure element which, in the event of at least partial overturning of the vehicle, closes under the effect of its weight a first valve seat to constitute a safety valve which prevents fuel from escaping from the tank by the vent pipe; and
- A second movable closure element which, when the vehicle is stopped in a substantially horizontal position, closes under the effect of its weight a second valve seat to form a vent valve whose opening is caused by vibrations generated during the running of the vehicle which move the second movable closure element from its closed position.

 In this second document, the first movable valve closure element is constituted by an upper shutter fixed to a ball forming a counterweight which, when the vehicle is turned over, closes under the effect of its weight a first upper valve seat arranged in a first upper part of the device housing.

 The second movable closure element is constituted by the ball forming a flyweight proper which, under the effect of its weight, closes a second lower valve seat which is arranged axially opposite the upper seat in a second lower part. of the housing.

 To guarantee the proper functioning of such a device with its two opposite upper and lower seats formed in two assembled parts of the housing, it is necessary that these two parts be produced with precision and assembled reliably to be sure that the two seats are substantially aligned and that the sealed closure of one or the other, depending on the conditions of use, is carried out effectively.

 In addition, the upper shutter must be reliably fixed to the ball forming a counterweight and its upper free end forming a shutter may present risks of jamming in the upper seat.

 Finally, this design does not benefit from the advantages inherent in the presence of a float as in the case of document EP-A-0,254,631.

 The object of the invention is to propose a device for venting and safety which overcomes the drawbacks which have just been mentioned.

For this purpose, the invention proposes a device for venting and safety for a fuel tank of a motor vehicle, of the type comprising a housing of which a lower end is connected to the upper part of the fuel tank and of which the upper part is connected to a section of a pipe for venting the upper part of the tank, of the type comprising
- A first movable closure element which, in the event of at least partial overturning of the vehicle, closes under the effect of its weight a first valve seat to constitute a safety valve which prevents fuel from escaping from the tank by the vent pipe; and
- A second movable closure element which, when the vehicle is stopped in a substantially horizontal position, closes under the effect of its weight a second valve seat to form a vent valve whose opening is caused by vibrations generated during the running of the vehicle which move the second mobile closing element from its closed position, characterized in that the two valve seats are carried by an intermediate transverse partition of the housing which delimits in the latter:
- A lower chamber in which the first valve closing element is mounted mobile and which is connected to the upper part of the tank; and
- An upper chamber in which the second valve closure element is movably mounted and which is connected to the section of the vent pipe.

According to other features of the invention
- the first movable closure element is carried by a float mounted to slide in the lower chamber between
- a low rest position towards which it is recalled by its weight and in which the safety valve is open
- And a high position towards which it is lifted by the fuel when the filling of the tank reaches a predetermined value and in which the first movable closing element closes the first valve seat.

- The free upper end of the float is shaped into a conical needle which constitutes the first movable closure element which is capable of cooperating in leaktight manner with the first valve seat of complementary frustoconical shape
- The second movable closure element is a ball which, when the vehicle is stopped in a substantially horizontal position, cooperates tightly with the second valve seat which is frustoconical
- the two frustoconical seats are aligned and emerge by their small ends in a common channel which extends through the intermediate partition
- The two valve seats are formed in the same valve body carried by the intermediate partition and made of flexible material, in particular of elastomeric material;
- The intermediate partition has a central hole in which is mounted the valve body which has a central channel which opens out by its two opposite lower and upper ends in the first and second seats respectively
- the device comprises a balancing valve which puts the two chambers in communication when the pressure in the upper chamber is greater than the pressure in the lower chamber
- the balancing valve is carried by the intermediate partition of the housing
- The balancing valve has a hole which passes through the intermediate partition and a third elastically deformable closing element, which is carried by the intermediate partition, which normally extends under the underside of the latter to close the lower end of the hole, and which deviates from its normal position towards the interior of the lower chamber when the pressure in the upper chamber is greater than the pressure in the lower chamber to open the balancing valve
- The third closing element is a sealing lip belonging to a sealing cup and which extends opposite a series of holes which pass through the partition and which are distributed around the central part of the intermediate partition which has first and second valve seats
- The sealing cup and the valve body are made integrally by molding in one piece from flexible material, in particular from elastomeric material.

Other characteristics and advantages of the invention will appear on reading the following detailed description for the understanding of which reference will be made to the accompanying drawings in which
- Figure 1 is a schematic sectional view of a motor vehicle tank provided with a filling device and a venting device according to the teachings of the invention;
- Figure 2A is a detail view on a larger scale which illustrates the venting device of Figure 1 shown in axial section, the various components being in the position they occupy when the vehicle is at '' and the tank is partially filled
- Figure 2B is an enlarged view of the upper part of Figure 2A
- Figures 3 to 6 are views similar to that of Figure 1 in which the venting device is shown respectively in four other operating positions
- Figure 7 is a view similar to that of Figure 2B which illustrates a first alternative embodiment of the venting device according to the teachings of the invention;
- Figure 8 is a view similar to that of Figure 2A which illustrates a second alternative embodiment of the invention; ; and
- Figures 9 and 10 are views similar to those of Figures 2 and 5 which illustrate a third alternative embodiment of the invention.

 FIG. 1 shows a tank 12 of motor vehicle fuel which is provided with a filling device 14 and with a venting device 16 in accordance with the teachings of the invention.

 In known manner, the filling device 14 comprises a filling tube 18, a lower end 20 of which opens into the reservoir 12, at the lower part of the latter, and an upper end 22 of which is intended to receive a filling gun (not shown) and to be closed by a plug.

 The tank 12 also includes a venting device 16 connected to a section 28 of a venting pipe which opens into the tank 12 at its upper partition 30 with interposition of the device 16.

 The venting device 16, as will be explained below, makes it possible in particular to compensate for the drop in the fuel level 26 in the tank 12 by allowing the admission of air inside the tank 12 so that the pressure prevailing in the tank is substantially constant.

 On the contrary, the venting device 16 must also allow the evacuation of gases which would be compressed inside the tank due to the expansion of the fuel 32 contained in the tank 12 following a rise in temperature and in order to avoid any deformation of the reservoir 12 liable to cause it to rupture.

 However, the venting device 16 is also a safety device which must not allow fuel to escape from the tank in the event of the vehicle overturning for obvious safety reasons.

 As can be seen in Figure 2A, the device 16 is essentially constituted by a housing 34 which is for example a molded plastic part.

 The housing 34 comprises a main body in the form of a lower cylindrical skirt 36 whose axis X-X is normally substantially vertical.

 The skirt 36 is open axially downwards at its lower end 38 and it is closed at its upper part by a horizontal partition 40, produced integrally by molding, which is extended radially by a wing 42 in the shape of a coated L, which allows to fix the housing 34 on the upper partition 30 of the tank 12 for example by means of a bead 44 of solder or glue.

 The skirt 36 extends axially through a corresponding hole 46 formed in the upper partition 30 and means 48 are provided for angular indexing, around the axis XX of the device 16 relative to the reservoir 12, in particular for angularly orient a connection pipe 50, which is produced integrally by molding with the housing 34 and which extends radially at its upper part to constitute a connection capable of receiving the end of the section 28 of the setting pipe. 'outdoors.

 The internal radial end 52 of the connecting pipe 50 extends radially from an upper cylindrical skirt 54 of the housing 34, produced integrally by molding, which extends vertically upwards above the partition 40 , the diameter of which is less than that of the lower skirt 36 and the upper end 56 of which is closed in leaktight manner by an attached plug 58, glued or welded, the internal underside of which has a spherical recess 60.

 The lower skirt 36 with the central part of the partition 40 delimits radially, and vertically upwards, a lower chamber 62 while the upper skirt 54 and the plug 58 delimit radially outwards and vertically upwards, an upper chamber 64 which is delimited vertically downwards by the partition 40.

 The partition 40 has in its central part a series of axial through holes 66 which are angularly distributed in a regular manner around the axis X-X and which bring the chambers 62 and 64 into communication.

 The internal cylindrical face 68 of the lower skirt 36 comprises a series of axial ribs 70 which guide in axial sliding a float 72 while delimiting as many axial passages between the ribs.

 The float 72 is a hollow molded part formed essentially by an annular cylindrical skirt 74 which is closed at its upper part by a frustoconical upper partition 76 which ends in a needle 78 of conical external profile 80 which constitutes, in the sense of the invention, the first movable closure element.

 The body of the float 72 comprises an internal cylindrical tube 82, the external surface of which serves as a guide for a helical compression spring 84 which bears at its upper end against a radial shoulder of the tube and whose lower end bears against the upper face facing 86 of a counterbore 88 formed in a bottom 90 which is an insert elastically fitted into the open lower end 38 of the lower skirt 36.

 The bottom 90 has a central hole 92 which places the lower chamber 62 in communication with the upper part of the tank.

 In the rest position illustrated in FIG. 2, the action of the spring 84 and the total mass of the float 72 are such that the latter is in the low vertical position, illustrated in FIG. 2, in which a slight axial clearance exists between the lower annular face 94 of the skirt 74 of the float 72 and the annular upper face opposite 96 of the bottom 90 so as to ensure communication between the chamber 62 and the upper part of the tank, through the device 16.

 The needle 78, forming the first movable closure element, extends partially inside a first frustoconical valve seat 100 whose angle is substantially identical to that of the external conical surface 80 of the needle 78 and which is formed in a molded piece of elastomeric material 102 which constitutes a single valve body within the meaning of the invention which is carried by the internal portion of the partition 40 which constitutes, within the meaning of the invention, the intermediate partition 104 between the chambers lower 62 and upper 64.

 The valve body 102 is a molded piece of elastomeric material which has an annular cylindrical central part 106 which is mounted, by elastic deformation, inside an axial channel 108 formed in a central cylindrical flange 110 of the intermediate partition 104 .

 The central part 106 of the valve body 102 internally delimits a stepped through channel 113 which places the lower valve seat 100 in communication with an upper valve seat 112 formed by the internal radial edge of a concave frustoconical bearing surface 114 formed in the upper face 116 of an upper radial flange 118 of the valve body 102.

 The upper valve seat 112 constitutes the second valve seat within the meaning of the invention with which cooperates, in particular in the position illustrated in FIG. 2, a spherical ball 120 forming a counterweight which constitutes the second movable valve closing element in the sense of the invention and which is arranged in the upper chamber 64.

 The lower valve seat 100 is formed in the lower face 122 of a lower radial flange 124 of the valve body 102 which itself extends radially outwards by an elastically deformable sealing lip 126, in the form of a cup. sealing, the annular edge of free end 128 of which is normally in axial upward abutment, against the portion facing the internal transverse face 130 of the upper partition 40, so as to constitute a valve which tightly closes the upper chamber 64, the holes 66 of which open opposite an area sealed by the lip 126.

 The different modes of operation of the device 16 will now be described.

 In the rest position illustrated in FIGS. 2A and 2B, the upper part of the reservoir 12 communicates with the lower chamber 62 of the device 16 but this lower chamber 62 is separated in leaktight manner from the upper chamber 64 by the ball 120 which cooperates so watertight with the seat 112 to constitute a safety valve which prevents in particular that the fuel vapors present at the top of the tank, or where appropriate the fuel, does not escape through the venting line 28.

 In the position illustrated in FIGS. 2A and 2B, the pressures prevailing in the chambers 62 and 64 are substantially equal and the third movable closure element, within the meaning of the invention, constituted by the lip 126 forming a sealing valve is closed.

 When filling the tank through the filling tube 18, the air and / or the fuel vapors contained in the upper part of the tank 12 escape through the vent pipe 28 passing through the hole 92 and around the float 72 between the ribs 70 to the passage formed by the radial clearance existing between the needle 78 and the valve seat 100 to reach the upper seat 112 normally closed by the ball 120. The pressure prevailing in the lower chamber 62 gradually increases during filling and, when the pressure difference between this chamber and the upper chamber 64 reaches a predetermined value, it causes the ball 120 to rise and therefore the pressurized gases to escape towards the setting pipe. air to allow filling with fuel.

 FIG. 3 shows the position occupied by the float in the event of excessive filling of the tank.

 In this position, we see that fuel 32 has penetrated into the lower part of the lower chamber 62 and that it has caused the rise, under the effect of Archimedes' push, of the float 72 until the needle 78 comes to cooperate sealingly with the lower valve seat 100 in order to seal the upper part of the lower chamber 62 which can therefore oppose any additional filling of the reservoir 12 insofar as the air contained in the upper part of the latter can no longer escape through the pipe 28.

 FIG. 4 shows a state of the device 16 in which during the running of the vehicle and under the effect of the vibrations due to running, the ball 120 has left the upper seat 112 by rolling on the frustoconical bearing surface 114 of so as to put in communication, as has been explained previously, the interior of the upper part of the tank 12 with the connection pipe 50 and therefore the venting pipe 28.

 This opening of the vent valve, formed by the cooperation of the ball 120 with the seat 112, regularly ensures the venting of the upper part of the reservoir 12, however, avoiding that it is permanently open, thus limiting the flow of fuel vapor which evaporates.

 In the state illustrated in FIG. 5, there is a vacuum inside the tank 12, that is to say that the pressure prevailing in the lower chamber 62 of the device 16 is then lower than the pressure prevailing in the room 64.

 This pressure difference, due to the presence of the holes 66, causes the opening by elastic deformation of the valve formed by the lip 126 and air can be admitted, firstly into the lower chamber 62, which penetrates through the intake pipe 50 in the upper chamber 64 and which passes through the holes 66 in the lower chamber 62.

 Communication is clearly understood between the upper chamber 64 and the lower chamber 62 of the device 16 and the valve 126 remains open until the pressures between the inside and the outside of the tank 12 are balanced.

 FIG. 6 shows the position occupied by the various components in the event of the vehicle overturning.

 In this position, the float 74 which is inverted occupies a low gravity position which is such that the needle 78 sealingly closes the valve seat 100 to prevent the fuel contained in the upper part of the tank 12 which has entered the chamber 62 does not accidentally escape through the vent pipe 28.

 Finally, it will be noted that the spring 84 is a compensation spring which intervenes to compensate for the weight of the float 74 in order to actuate the latter in the event of a pronounced inclination of the vehicle.

 The venting and safety device 16 which has just been described with reference to FIGS. 2 to 6 thus constitutes an autonomous assembly which can be mounted very easily and without modification, either at the top of the tank. 12, as illustrated in FIGS. 1 to 6, or on the filling tube 18.

 The device 16 can also be associated with another device in series, the housing or body being able in this case to include several connecting pipes for this purpose.

 The first variant embodiment illustrated in FIG. 7 will now be described in which components identical, similar or analogous to those described above are designated by the same reference numbers.

 In order to improve the fixing of the valve body 102 on the intermediate partition 104, there is provided a mounting and locking piece 140 which is a piece of stamped sheet metal.

 This comprises an internal ferrule 142 which includes a bulge or external radial rib 144 of toroidal shape which tightens radially outwards the central tubular cylindrical body 106 of the valve body 102 so as to improve its tight fixing in the intermediate partition 104 .

 The ferrule 142 is extended at its upper part by a frustoconical veil 146 which delimits the upper sealing seat 112 and the frustoconical surface 114 on which the ball 120 is capable of rolling.

 The operation of the device 16 illustrated in FIG. 7 is identical in all respects to that described above with reference to FIGS. 2 to 6.

 In the variant embodiment illustrated in FIG. 8, the lower 100 and upper 112 valve seats are produced directly from molding with the housing 34, that is to say directly in the intermediate partition 104 with its central part 110, and the lip 126 forming a valve for the holes 66 is an elastomer molded part which is fitted elastically around the lower part of the central portion 110 inside which the frustoconical seat 100 is delimited.

 The operation of the second variant of the device 16 illustrated in FIG. 8 is identical in all respects to that described above with reference to FIGS. 2 to 6.

 The third variant embodiment illustrated in FIGS. 9 to 10 will now be described.

 In this third variant embodiment, the lower valve seat 100, with which the needle 78 may cooperate, is also produced directly from molding with the central portion of the intermediate partition 104.

 The seat 100 communicates with the stepped channel 113 and the intermediate partition 104 is completed by an added top plate 150 which is pressed against an upper annular shoulder 152 of the intermediate partition 104 by a ferrule 154 belonging to the cover 58.

 The central part of the plate 150 complementary to the intermediate partition 104 has a circular central hole 156 and it is divided into a comb by notches 159 distributed angularly in a regular manner around the axis XX so as to constitute as many passages through this central part.

 The partial circular orifice 156 constitutes a vertical support edge for the ball 120 whose spherical surface cooperates in leaktight manner, when the pressures are equal in the chambers 62 and 64, with the annular edge opposite 112 d an annular sealing membrane 158 which is tightly clamped by the upper plate 150 bearing against an upper annular shoulder 162 of the intermediate partition 104.

 The inner circular edge 112 of the membrane 158 thus constitutes the upper valve seat 112 with which the ball 120 cooperates when the latter is in its rest position illustrated in FIG. 9.

 Due to the flexible design of the membrane 158, its internal radial portion located under the comb 158 also constitutes a sealing valve 126 elastically deformable in the event of pressure differences between the chambers 64 and 62 to put the connecting pipe into communication. 50 with the channel 116 and therefore with the lower chamber 62.

 Finally, the ball 120 can roll on the concave frusto-conical upper face 144 of the plate 150 complementary to the intermediate partition 104 to put the chambers 62 and 64 into communication.

 The other operating modes of the device 16 illustrated in FIGS. 9 and 10 are identical to those described above with reference to the first two embodiments.

Claims (12)

 1. Device (16) for venting and safety for a tank (12) of motor vehicle fuel, of the type comprising a housing (34) of which a lower end (36) is connected to the upper part of the fuel tank (12) and the upper part (50, 54) of which is connected to a section of a pipe (28) for venting the upper part of the tank, of the type comprising  - A first movable closing element (72, 78) which, in the event of at least partial overturning of the vehicle, closes under the effect of its weight a first valve seat (100) to constitute a safety valve which prevents the fuel does not escape from the tank (12) through the vent pipe (28); and  - A second movable closure element (120) which, when the vehicle is stopped in a substantially horizontal position, closes under the effect of its weight a second valve seat (112) to constitute a shut-off valve free air, the opening of which is caused by vibrations generated during the running of the vehicle which move the second movable closing element from its closed position  characterized in that the two valve seats (100, 112) are carried by an intermediate transverse partition (104) of the housing (34) which delimits therein:  - a lower chamber (62) in which the first valve closure element (72, 78) is movably mounted and which is connected to the upper part of the reservoir (12); and  - An upper chamber (64) in which the second valve closure element (120) is movably mounted and which is connected to the section of the vent pipe (28).  2. Device according to claim 1, characterized in that the first movable closure element (78) is carried by a float (72) slidably mounted in the lower chamber (62) between  - a low rest position towards which it is recalled by its weight and in which the safety valve (100, 78) is open  - And a high position towards which it is lifted by the fuel when the filling of the tank (12) reaches a predetermined value and in which the first movable closure element (78) closes the first valve seat (100).  3. Device according to claim 2, characterized in that the free upper end of the float (72) is shaped as a conical needle (78) which constitutes the first movable closure element which is capable of cooperating in leaktight manner with the first valve seat (100) of complementary frustoconical shape.  4. Device according to any one of the preceding claims, characterized in that the second movable closure element is a ball (120) which, when the vehicle is stopped in a substantially horizontal position, cooperates in leaktight manner with the second valve seat (112, 114) which is frustoconical.  5. Device according to claim 4 taken in combination with claim 3, characterized in that the two frustoconical seats (100, 112, 114) are aligned and open at their small ends in a common channel (113) which extends to through the intermediate partition (104).  6. Device according to any one of the preceding claims, characterized in that the two valve seats (100, 114) are formed in the same valve body (102) carried by the intermediate partition (104) and made of flexible material , especially made of elastomeric material.  7. Device according to claim 6, characterized in that the intermediate partition (104) has a central hole (108) in which is mounted the valve body (102) which comprises a central channel (113) which opens at its two ends opposite lower and upper in the first (100) and second (114) seats respectively.  8. Device according to any one of the preceding claims, characterized in that it comprises a balancing valve (66, 126) which puts the two chambers (62, 64) in communication when the pressure in the upper chamber (64 ) is greater than the pressure in the lower chamber (62).  9. Device according to claim 8, characterized in that the balancing valve (66, 126) is carried by the intermediate partition (104) of the housing (34).  10. Device according to claim 9, characterized in that the balancing valve has a hole (66) which passes through the intermediate partition (104) and a third closing element (126) elastically deformable, which is carried by the intermediate partition (104), which normally extends under the lower face (130) of the latter to close the lower end of the hole, and which deviates from its normal position towards the interior of the lower chamber (62) when the pressure in the upper chamber (64) is greater than the pressure in the lower chamber (62) to open the balancing valve.  11. Device according to claim 10, characterized in that the third closing element is a sealing lip (126) belonging to a sealing cup and which extends opposite a series of holes (66) which pass through the partition (104) and which are distributed around the central part of the intermediate partition which comprises the first and second valve seats.  12. Device according to claim 11 taken in combination with one of claim 6 or 7, characterized in that the sealing cup (126) and the valve body (102) are made from  material by molding in a single piece of flexible material, in particular  made of elastomeric material.