GB2188913A

GB2188913A - A breather tube system for a vehicle fuel tank

Info

Publication number: GB2188913A
Application number: GB08708518A
Authority: GB
Inventors: Palu Attilio Dal
Original assignee: Fabbrica Italiana Serrature Torino FIST SpA
Current assignee: Fabbrica Italiana Serrature Torino FIST SpA
Priority date: 1986-04-11
Filing date: 1987-04-09
Publication date: 1987-10-14
Anticipated expiration: 2007-04-09
Also published as: DE3711781A1; IT8667297A0; GB2188913B; IT1189661B; FR2597034A1; FR2597034B1; GB8708518D0

Description

GB 2 188 913 A duct 7 to which is connected one end of a breather tube 8

which at the other end is connected to a duct 9 SPECIFICATION which opens into the end 5 of the main tube 4. In the intermediate section and at a lowermost point of the A breathertube system for a vehiciefuel tank 70 breathertube 8, is interposed a breather valve 11 formed according to the present invention, better The present invention relates to a breather tube seen in detail in Figure 2. In particular, this valve 11 is system for a vehicle fuel tank, in particular for motor conveniently integrally made of piastics material and vehicles. has a first part 12 the interior of which forms a duct 13 As is known,fuel tanks are provided with a 75 with two end sections 14, and a second part 15, per breathertube connected to an aperture nearthe up- penclicularto the first part 12, forming an inner permost portion of the tank, which opens into an in- chamber 16 open atthe lower end and communicat itial section of the fuel filler pipe forfilling thetank ing at the top with the duct 13 by means of an orifice from the outside, and permits the escape of air and 17. In this chamber 16 is housed a float element 18, the re-cycling of fuel and foam which passes through 80 conveniently made from a casing of plastics enclos this breathertube during f illing of the tank itself and ing air, having a flat lower base and a hemispherical returns along the main fillertube to the tank. upper portion, and operable to close the orif ice 17 Usually, it is sought to dispose this breathertube when it is thrust upwardly in a manner which will be in such a way that it does not have any dips in it so as described in more detail hereinbelow. At the bottom notto create syphoning zones and to preventfuel 85 this second part 15 has inwardlyfolded projections from lying in a region of thetube itself at a lower level 19 which preventthe element 18from coming loose which could cause, during a subsequentfilling of the and escaping from the chamber 16. The substantial tank, obstruction of the air passage in the breather lower part of the second part 15 is fitted into a hole in tube itself and therefore malfunctioning of the thetank 1, with the interposition of an annularseal breather system. However, there exist situations 90 element 20, conveniently of rubber, having an upper upon assembly of this breathertube in which either radial outer lip 21 which is interposed between the because of the particular shape of the bottom of the lower surface of the first part 12 and the annular vehicle, due to cross members etc., orto automatic outer surface around the aperture in the tank 1, assembly stages of the tank with the tube connected, whiistthe lower portion of this seal body 20, con where it is not conveniently possible to avoid the forveniently of frustoconical form, is sealingly def mation of the said dips with the associated syphon ormed outwardly by an annular outer projection 22 zones. of wedge-shape section, present on the part 15. The The object of the present invention is that of prov- two ends 23 of the breather tube 8 between which the iding a breathertube system for a vehicle fuel tank breathervalve 11 is interposed, arefitted onto two which avoids the disadvantages indicated above of 100 end sections 14 of the first part 12, with the interposi failure of failure of the breathersystem in all distion of sealing sleeves 25, conveniently of elastic positionswhich the breathertube can find itself. material, and on these end sections 14 areformed According to the present invention there is prov- external teeth or projections 24which preventthe ided a breathertube system for a vehicle fuel tank, end 23 from coming off the tube 8.

characterised by the factthat in the lowermost re- 105 The operation of the described system comprising gion of the said brethertube is disposed a valve op- the breather tube 8 and the breathervalve 11 is as erabie to provide communication between the said follows. During filling of fuel into the tank 1 via the tube and the interior of the said tankwhen the fuel main inlettube 4 the normal escape of fluid from the level in the tank is less than a predetermined value, upperzone of the tank 1 via the breathertube 8,the and to close the said comnlunication when the fuel 110 inner part of which is completely free takes place. In level in the tank exceeds the said value. these conditions, in which the float element 18 is not For a better understanding of the present inven- contacted by the fuel, it is in the lower position illust tion a particular embodiment is now described, rated in Figure 2 and is retained by the projections 19 purely by way of non-limitative example, with refer- so thatthe orifice 17 is open. When the volume of ence to the attached drawings, in which: 115 fuel in the tank 1 increasesto a value such as to cause Figure 1 is a schematic side view of a fuel tank and an internal vapour pressure such as to disturb the the associated fuel filler and breathertubes, in a normal passage of fluid in the breathertube towards system according to the principles of the present in- the duct 9, in these conditions the fuel level in the vention; and tankl reaches a value such as to bring the float el- Figure2 is a sectional view on an enlarged scale of 120 ement18ofthebreathervalvell into the completely a portion of the breathertube of Figure 1. upwardly raised position such as to closethe orifice With referenceto Figure 1,the reference numeral 1 17, so thatfilling of the tank 1 can continue and the indicates a fuel tank of known type, which is dis- whole of the section of the breathertube 8 between posed beneath the bottom 2 of the vehicle indicated the ducts 7 and 9 has no apertures along its length.

by way of example in broken outlines, and having for 125 When filling of fuel into the tank 1 is complete it can example a lower cross member 3. To the tank 1 is happen that a certain quantity of fuel is trapped in the connected a main fuel fillertube 4 having an end 5 of breathertube 8 so that it remains in its lowermost known type, conveniently closed by a plug not illust- section in correspondence with the breathervalve rated and opening to the exterior of a portion 6 of the 11, that is to say within the ends 23 of the duct 13.

vehicle body. From an upper zone the tank 'I hasa 130 When, during use of the vehicle, the level of fuel in 2 GB 2 188 913 A 2 the tank reduces and fails below the level of the float is seaiingly fitted into a hole in the wall of the said element 18,this returnstothe position illustrated in tank by means of an annular rubber element.

Figure2 sothatitopensthe orifice 17 andthefuel 7. A system according to any Of Claims from 3 to lying in the breathertube 8 can escape through this 6, characterised by the fact taht the said breather orifice 17 towards the chamber 6 and then flow into 70 tube is corrugated at least internally and is sealing ly the tank 1; in this way the interior of the breather coupled to relieved portions towards the end of the tube 8 is completely evacuated so thatthe breather said first portion.

Claims

tube 8 can again operate in the correct manner upon 8. A system according

to any of Claims from
2 to subsequent refilling of fuel into the tank 1. 7, characterised by the fact that the said float element The advantages obtained with the system com- 75 is composed of plastics material enclosing air.

prising the breathertube 8 and the interposed 9. A breather valve fora breathertu be system ac breather valve 11 are evident from what has been de- cording to any of the preceding Claims.

scribed in that with a very simple arrangement the 10. A breather tube system fora vehicle fuel tank correct operation of the breather for the tank 1 isen- and an associated breathervalve as describedwith suredwhatever position the breathertube8 80 referencetothe attached drawings.

assumes.

Finally, itis clearthatthe described in and illustra ted embodiment of the present invention can be Printed for Her Majesty's Stationery Office by Croydon Printing Company (U K) Ltd,8187, D8991685.

modified and varied without departing from the Published by The Patent Office, 25 Southampton Buildings, London, WC2A l AY, scope of the invention itself. For example, thetwo from which copies may be obtained.

end sections 14 of thefirst part 12, ratherthan having coincident axes, can be disposed at an angle to one another, conveniently both inclined downwardly to the orifice 17. Moreover, the breathertube 8 can be a corrugated tube, at least over a part of its interior, so as to be sealingly fixed atthe end sections 14 with the simple direct coupling of the projections 24 of these sections 14 into the interior groove of the breather tube 8 as described in Italian utility model applica tion No. 54042-13185 filed 15 November 1985 bythe same applicant.

CLAIMS 1. A breather tube system fora vehicle fuel tank characterised by the factthat in the lowermost zone of the said breather tube is disposed a valve operable to provide a communication path from the said tube to the interior of the said tank when the level of fuel in the tank is lower than a predetermined value, and to close the said communication when the level of fuel in the tank exceeds the said value. - 2. A system according to Claim 1, characterised bythe factthat the said valve includes afloat element operable to close a communication orifice between the said tube and the said tank in dependence on the level of fuel in the tank.
3. A system according to Claim 2, characterised bythefactthatthe said valve has a first portion con nectedto a continguous end of the said breather tube, and a second portion housing the said float el ement and disposed partially in the said tank, the said first and second portions communicating inter nallythrough the said orifice.
4. A system according to Claim 3, characterised by the fact that the said first portion includes at least one duct section having two ends in the lowermost zone of which the said orifice isformed.
5. A system according to Claim 3 or Claim 4, char acterised bythe fact that the said second portion in cludes a duct section open towards the tank and has projections for preventing the escape of the said float element.
6. Asystem according to anyof Claims3to 5, characterised by the fact that the said second portion