Abstract:
A vapor vent hose is adapted to be assembled to a nipple. The nipple has a first end, an outside diameter and a barb. The barb has a tapered first end adjacent the end of the nipple and a second end with a substantially radially extending face. The hose and nipple are provided in a fuel vapor system. The hose has a first end with an inside diameter fitting over the nipple. The first end has a cuff axially spaced from the end of the hose. The cuff is substantially undeformed radially after installation over the barb.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a system vent line and more particularly to such a vent line formed from a vacuum form process. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 5,139,043 assigned to the assignee of the present invention, which is incorporated herein by reference, illustrates a vent line as shown in FIG. 2 of the &#39;043 patent at 85 connected to a nipple 36. As illustrated therein, the vent line is formed from a rubber material and involves an interference fit to a barb formed on the nipple. Although this is an effective connection, it is difficult to assemble due to the force required to push the line over the barb. Furthermore, the expense of the rubber hose is greater than would be desirable. 
     U.S. Pat. No. 4,972,875, provides for a plastic fuel line formed from a vacuum form process, as illustrated in FIGS. 2-4 of the &#39;875 patent. As illustrated in FIGS. 3 and 4, and described in column 3-4, the hose 64 of the &#39;875 patent involves an interference fit of the side walls 2 a  barbed nipple. The hose of the &#39;875 patent is directed toward high pressure fuel system and therefore an interference fit along the side walls is important to accommodate the high pressures. However, such an interference results in an excessively high force to assemble the hose to the nipple. 
     It would therefore be desirable to provide low cost vent vapor hose having a connection which is easy to assemble. 
     SUMMARY OF THE INVENTION 
     Accordingly, to provide an inexpensive hose which is easy to assemble, a vapor vent hose is provided to be assembled to a nipple having a radial barb. The hose includes a cuff that is substantially radially undeformed after installation to the barb. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a fuel tank vapor vent valve having a tube attached to it according to the present invention; 
     FIG. 2 is an illustration of a tube for a connection according to the present invention, in partial sectional view; 
     FIG. 3 is a partial sectional view of an alternative embodiment of an assembly according to the present invention; 
     FIG. 4 is a partial sectional view of an alternative embodiment of a tube according to the present invention; 
     FIG. 5 is an isometric view of an alternative embodiment according to the present invention; 
     FIG. 6 illustrates a canister vent valve having a tube attached to it according to the present invention; 
     FIG. 7 illustrates a filter having a tube attached to it according to the present invention; and 
     FIG. 8 schematically illustrates a fuel system with vent valve tubes according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 1, a vapor vent valve  12  is provided in a fuel tank  14 . A hose  16  is connected to the vent valve  12 . As shown in FIG. 2, the vent valve  12  includes a nipple  18  to which the hose  16  is connected through a press fit operation. The nipple  18  has an outer diameter  24  engaged by the inside of the hose  16 . In a preferred embodiment, the hose  16  has an inside diameter  26  having a clearance to the outside diameter  24  of the nipple. The nipple further includes a barb  20 , which in a preferred embodiment is provided over half the circumference thereof, or 180 degrees, as shown in FIG.  2 . Alternatively, the barb could extend for a lesser degree, depending on the level of retention desired. 
     The hose  16  includes a cuff  22  for engagement with the barb. The cuff includes a radially extending face  21  for engagement with a corresponding radially extending face  23  of the barb  20 , thereby preventing pull-off of the hose  16  from the nipple  18 . The cuff  22  provides for a clearance fit to the barb, or at most a slight interference fit, and therefore the hose  16  after installation is not substantially deformed by the barb  20 , thereby making installation of the hose relatively easy, because the hose  16  does not require a large deflection about the circumference thereof during installation over the barb  20 . Thus, the cuff  22  is substantially undeformed after the hose  16  is installed to the nipple  18 , but the cuff  22  is deflected radially while the cuff  22  is installed over the barb  20 . In a preferred embodiment, a clearance fit is provided between the inside diameter  26  of the hose to the outside diameter  24  of the nipple to make insertion effort relatively easy. Similarly, the open end of the hose  16  (the left of the hose  16  in FIG. 1) has a clearance fit or minimal interference fit to the nipple  18 , thereby minimizing the installation effort thereof. 
     In a preferred embodiment, the hose  16  is vacuum formed from a nylon-6 material in a manner known to those skilled in the art. Preferably the hose  16  includes a plurality of convolutions  17  formed therein along the length thereof, the convolutions aiding in the flexibility of the hose  16 . In FIG. 1, a clamp  500  is shown, but one skilled in the art appreciates, in view of the present disclosure that not all applications according to the present invention require such a clamp. 
     FIG. 8 shows an automotive powerplant having fuel vapor storage system (FVSS) integrally disposed therein, as described in detail in copending application Ser. No. 09/050,139, assigned to the assignee of the present invention, which is incorporated herein by reference. Although some of the powerplant&#39;s specific components, geometry, and component names may differ from vehicle to vehicle, the primary structure and structural components will remain constant. Primary components of the automotive powerplant are fuel tank  810  and internal combustion engine  812 . Liquid fuel enters the vehicle by first being introduced to the fuel inlet opening  814  then traveling through fuel filler tube  816  into fuel tank  810 . Fuel is sent by fuel pump  818  through fuel filter  820  and to engine  812  by way of fuel line  822 , fuel rail  824 , and fuel injectors  826 . Optionally, some systems will recycle fuel unused by engine  812  by sending it back to fuel tank  810  via the fuel return line  828 . 
     There are generally two primary circumstances wherein fuel vapor filled air is forced out of fuel tank  810 . The first circumstance is during the above outlined filling of tank  810  and the other occurs when the fuel vapor in the tank expands (usually due to increased temperature of the fuel and/or fuel vapor) and forces some of the fuel vapor out of the tank. In either case, the fuel vapor filled air is sent through fuel recovery line  830  to carbon canister  832  where it is cleaned of its vapor before being sent to the atmosphere. Carbon canister  832  is filled with activated carbon which adsorbs the fuel vapor from the air flow. 
     Periodically, carbon canister  832 , after absorbing and cleaning the fuel vapor filled air, must be desorbed, or purged, of the fuel vapor therein. This refreshing is done so that the canister can accommodate and absorb additional fuel vapor from fuel tank  810 . Atmospheric air, to be used as purge air, is forced into and out of canister  832  and then sent through vapor purge line  834 , and canister purge valve  836 , directly to engine  812  for utilization. 
     As mentioned above, the outdoor air used as purge air must be cleaned of substantially all matter and moisture before it is introduced to canister vent valve  838  (CVW) and carbon canister  832 . This is the purpose of the air filter assembly  840 . In a preferred embodiment, the above-described hose connections are embodied in the connections between the canister  832  and vent valve  838  and air filter  840  within lines  859 ,  859 . One skilled in the art may further apply the present invention to the other hoses as described below, particularly using a hose end made from a material comprising either a thermoplastic rubber (TPR) or thermoplastic elastomer (TPE), collectively called TPR/TPE, and/or hose clamps as described below. Examples of this include hoses  830 ,  834 ,  835 ,  815  and  817 , as illustrated in FIG.  8 . One skilled in the art further appreciates in an alternative embodiment that fuel lines, for example as provided in U.S. Pat. No. 4,972,875, could be modified to use a hose according to the present invention. 
     As appreciated by one skilled in the art, this hose  16  illustrated in FIGS. 1-8 is best suited for a low pressure fuel vapor vent system, although one skilled in the art could modify the present invention for other applications, especially using the clamp and/or elastomeric end. As further appreciated, those applications illustrated without an elastomeric end and/or a clamp are best suited for applications which do not require zero vapor loss. Examples include the vapor vent tubes  858 ,  859  provided after the canister  832  illustrated in FIG.  8 . 
     FIG. 3 illustrates a further embodiment including a 360 degree barb  20 ′ about the circumference of the nipple  18 ′ for engagement with the cuff  22 ′. As appreciated by one skilled in the art, this embodiment normally requires a higher assembly force, but will be more difficult to pull the hose  16 ′ from the nipple  18 ′. 
     As shown in FIG. 4, a further alternative embodiment is illustrated. A vacuum formed hose  416  is provided having an elastomeric material  430  bonded to one end thereof. As shown in FIG. 4, the elastomeric material  430  includes a molded cuff  422  having an analogous shape and function to the cuff  22  provided in the embodiment of FIG. 2 which was vacuum formed into the nylon hose  16  of FIG.  2 . Preferably, the hose  416  of this embodiment includes a plurality of molded ribs  432  to engage the molded elastomeric material  430  and provide positive retention thereto, as well as a leakproof seal therebetween. In a preferred embodiment, the elastomeric material  430  comprises a TPR/TPE material, a commercially available example of which includes SANTOPRENE. 
     In a further alternative embodiment, a clamp  500  as provided in FIG. 5 is engaged with an outer diameter of the hose  516 . The clamp  500  is preferably a spring type clamp of the constant pressure type as known to one skilled in the art. Such a clamp  500  is best suited for the TPR/TPE coupling  430  as provided in FIG. 4 to obtain an effective gas-tight seal between the TPR/TPE part  430  and the nipple  418 . Alternatively, such a clamp  500  could be applied to the hose  16  provided in FIG. 2, particularly to enhance the pull-off of the tube and to improve sealing between the hose  16  and nipple  18 . 
     In the embodiment of FIG. 4, as the TPR/TPE end  430  is assembled over the nipple  418 , the clamp  500  (not shown) is then provided on the outer diameter of the TPR/TPE end  430  and clampingly engages the TPR/TPE material  430  to the nipple  418  at a first end thereof  435 . This clamping arrangement provides a more positive engagement of the barb  420  on the nipple  418  to the cuff  422  in the hose and more positively prevents pull-off of the hose in addition to the sealing. Although illustrated as a barb of less than 360 degrees in FIG. 4, one skilled in the art appreciates extending the barb circumferentially in a manner similar to that described with reference to FIG. 3 above. 
     FIG. 6 illustrates a carbon canister vent valve  612  having a nipple  618  and a hose  616  attached thereto according to the present invention. Similarly, FIG. 7 illustrates an air filter  712  having a nipple  718  with a hose  716  attached thereto according to the present invention. One skilled in the art appreciates the air filter  840  of FIG. 8 is an application of such a connection. Likewise, carbon canister  832  of FIG. 8 may employ a similar connection with an outlet hose  859 . 
     While certain representative embodiments and details have been shown for the purpose of illustrating the invention, it will be apparent to those skilled in the art that various changes in the arrangement provided herein may be made without departing from the scope of the invention, which is defined in the following claims.