Abstract:
A fuel vapor recovery system for a vehicle includes a charcoal canister connected to the fuel tank for collecting fuel vapors from the tank as it is being refilled. After the tank is filled and the engine started, the charcoal canister is purged of accumulated vapors. As the canister is being purged, it receives atmospheric air to fill the purged volume. A filter is remotely connected by a hose to the air inlet of the canister. The filter assembly removes dirt, dust, and water from the incoming air.

Description:
BACKGROUND OF THE INVENTION 
     Certain proposed Environmental Protection Agency regulations require that new gas-powered passenger vehicles be equipped with an on-board fuel vapor recovery system. The system will collect fuel vapors emitted from the gas tank as it is being refueled. A charcoal canister collects and contains these vapors. After the tank is filled with gasoline, and the engine is started, the accumulated vapors pass from the charcoal canister to the engine. Purging of the canister requires make-up air to fill the purged volume. This make-up air must be clean, fresh and dry. Any contaminants such as dirt, dust, or water entering the canister can affect the efficiency and operation of the canister. 
     The size of the charcoal canister is directly related to the fuel tank volume. A large canister volume requires mounting the canister on the underside of the car. 
     SUMMARY OF THE INVENTION 
     The broad purpose of the present invention is to provide a filter assembly connected to the make-up air inlet of the charcoal canister for removing dirt, dust and water. The filter is intended to be mounted in a remote location with respect to the charcoal canister. The location is chosen so as to be protected. The filter is connected by a hose to the canister, remote from the harsh environment of the canister. 
     The preferred filter includes a tubular housing adapted to be disposed in an upright position with a bottom discharge opening connected by a hose to the canister. The upper end of the housing has an inlet opening for receiving air in a generally horizontal direction. The housing has an internal horizontal flat baffle wall immediately beneath the inlet opening. The baffle wall has centrally disposed openings for passing air from the upper end of the housing toward the lower end. 
     A tubular baffle is mounted on the horizontal wall adjacent to the air inlet so that moisture in the air tends to be knocked-off and drained out the inlet opening. The air passes upwardly and then reverses direction down through the tubular baffle toward the lower outlet opening. As the air passes through the housing, it progresses through several different types of filter media for removing foreign matter from the air. 
     Still further objects and advantages of the invention will become readily apparent to those skilled in the art to which the invention pertains upon reference to the following detailed description. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     The description refers to the accompanying drawings in which like reference characters refer to like parts throughout the several views, and in which: 
     FIG. 1 is a perspective view of a preferred filter assembly; 
     FIG. 2 is a view showing the fuel tank system on an automotive vehicle employing a charcoal canister and the filter assembly of FIG. 1, the vehicle outline being illustrated in phantom lines; 
     FIG. 3 is an elevational view of the filter assembly; 
     FIG. 4 is the bottom view of the filter assembly; 
     FIG. 5 is a longitudinal partially sectional view of the preferred filter assembly with the filter media removed; 
     FIG. 6 is a longitudinal sectional view of the filter assembly with the filter media in position; 
     FIG. 7 is a sectional view as seen along lines 7--7 of FIG. 5; and 
     FIG. 8 is a sectional view as seen along lines 8--8 of FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to the drawings, FIG. 2 illustrates the outline of an automotive vehicle 10 having a conventional gas tank 12 with a funnel-shaped opening 14. Gasoline is delivered through opening 14 and conduit 16 for filling the tank. A charcoal canister 18 is mounted on the tank for receiving vapors from the tank as it is being filled to prevent the vapors from exhausting to the atmosphere. 
     A filter assembly 20 is connected by a conduit 22, such as a flexible hose, to charcoal canister 18. The filter assembly is adapted to receive atmospheric air, filter the air and then pass it to the canister as it is being purged by the engine (not shown). The filter assembly is mounted at a location remote and separate from the canister. 
     Referring to FIGS. 1, 2 and 5, filter assembly 20 comprises an elongated, tubular cup-shaped housing 24 formed of a nylon material. 
     Housing 24 has a small diameter tubular duct 26 defining an outlet opening 28. Duct 26 is adapted to be telescopically received in the end of hose 22. 
     Housing 24 has an internal annular shoulder 30 spaced from the upper open end 32 of the housing. The upper end of the housing has an annular flange 34 defining the upper edge of the housing. The housing has four internal longitudinally extending rib means 36, as best illustrated in FIG. 5. 
     Referring to FIGS. 3 and 5, the housing has an elongated inlet opening 38 located a short distance above shoulder 30. 
     A cover 40 having a circular border is mounted on the upper open end of the housing. The cover has a diameter accommodating the diameter of flange 34, and a depending annular skirt 42. 
     The lower edge of skirt 42 terminates in eight equally-spaced locking lug means 44 which snap around flange 34 to permanently mount the cover on the upper end of the housing. As best illustrated in FIG. 3, locking lug means 44 are spaced from one another by gaps 46 which have a length slightly greater than the width of each lug. 
     Cover 40 is preferably formed of a nylon material. Cover 40 completely closes off the upper end of the tubular housing. The housing and the cover form an internal filter chamber 48. 
     A baffle 50 is mounted in the housing. Baffle 50 is a one-piece unit formed of nylon having a flat wall 52 with an annular flange 53 seated on shoulder 30. 
     Baffle 50 divides the internal chamber into an upper chamber 54 and a lower chamber 56. Baffle 50, as best illustrated in FIG. 7, has a central opening 58 and four spaced, smaller openings 60, 62, 64 and 66. Openings 58-66 are adapted to pass air from upper chamber 54 to lower chamber 56. 
     The baffle also includes a cylindrical wall 68 which is joined to wall 52 around openings 58 to 66. Wall 68 has a diameter less than the diameter of the housing wall and is spaced from inlet opening 38, as best illustrated in FIGS. 5 and 6. Wall 68 extends from wall 52 to cover 40. Wall 68 has four equally spaced notch means 70 disposed to permit air to pass from inlet opening 38 and around the top of wall 68. 
     Baffle wall 52 has four short, equally-spaced rib means 72 disposed between each pair of openings 60-66. The lower side of wall 52 also has tapered ribs 74 and 76. The inner edges of ribs 74 and 76 have their greatest depth adjacent opening 58 and then become tapered toward their outer ends adjacent flange 53. 
     Filter media 80 is disposed inside cylindrical wall 68. Filter media 80 is a pre-filter media formed of 20 PPI SIF foam material. 
     Four filter elements 82, 84, 86 and 88 are disposed between baffle wall 52 and the bottom of the tubular housing. Filter elements 82 and 86 are formed of a 15 denier polyester fiber felt and are identical in diameter and thickness. Filter media 84, sandwiched between elements 82 and 86, is preferably of a polyester fiber felt material, 40 percent 6 denier, and 60 percent 25 denier. 
     The bottom filter element 88 is adapted to contain very fine dirt and dust and any fibers which may break loose from the upstream elements. Preferably element 88 is of a 70 PPI SIF II foam. 
     Referring to FIG. 5, a dome shaped screen 90 is mounted in the bottom of filter chamber 56. The convex part of the screen faces the chamber and has a diameter accommodating the inner diameter of chamber 56. Screen 90 is preferably of a 4×4, 0.025&#34; diameter wire. The screen enlarges the bottom surface area of filter element 88 facing outlet opening 28 to improve the air circulation through chamber 56. 
     Referring to FIGS. 5 and 6, the air passes in the direction of arrow 90 through inlet opening 38, toward baffle wall 68. Wall 68 changes the direction of the air toward the cover, and causes water droplets and moisture to collect on top of wall 52 and drain out the inlet opening. The air passes radially inwardly through notch means 70 and then downwardly through the inside of the cylindrical baffle wall 68 where it passes through filter media 80. 
     As the air progresses downwardly, it passes through openings 58, 60, 62, 64, and 66 into lower chamber 56. Baffle ribs 74 and 76 depress filter media 82 away from the bottom of the baffle to enlarge the top area of the filter media. The air then passes through filter element 82 which is a low density filter and creates a velocity decrease for the incoming contaminants. The air passes through filter element 84 which traps the fine dust. The air passes through filter element 86 and then finally through the final stage of filtration through element 88 which removes very fine dirt and dust and any fine fibers which may have broken loose from the other elements. The air then passes through screen 90 and out outlet opening 28 toward the charcoal canister. 
     The filter assembly can be located in a position best suited for the incoming air, which may not be the location best suited for the charcoal canister.