Fuel tank assembly and baffle device

A baffle device, configured to be disposed near an outlet of a fuel tank, includes a fitting having an aperture therethrough and a first baffle. The first baffle includes a passageway in fluid communication with the aperture and a first baffle aperture configured to permit entry of fuel vapor into the passageway and exit of fuel vapor from the passageway. The baffle device also includes a second baffle overlying at least a portion of the first baffle aperture.

FIELD OF THE INVENTION

The present invention relates to internal combustion engines, and more particularly to fuel systems for internal combustion engines.

BACKGROUND OF THE INVENTION

Fuel systems for internal combustion engines often include a canister containing activated carbon that is connected to a fuel tank by a tube. Vapor vented from the fuel tank is routed to the canister to remove or adsorb hydrocarbons and other vapor emissions from the vapor before the vapor is vented to the atmosphere.

However, during operation of the engine or the equipment with which the engine is utilized, vibration of the engine or movement of the vehicle may cause fuel in the fuel tank to splash or slosh against the walls of the fuel tank. Excessive splashing or sloshing of fuel in the fuel tank may cause some fuel in the fuel tank to pass through the tube and leak into the canister. Once saturated with liquid fuel, activated carbon may become less efficient in removing or adsorbing hydrocarbons from the vapor vented from the fuel tank. Liquid in the venting system or carbon canister can adversely affect the operation of the fuel tank ventilation system.

SUMMARY OF THE INVENTION

The present invention provides, in one aspect, a baffle or liquid fuel barrier device configured for use with a fuel tank. The device substantially prevents liquid fuel from entering a carbon canister that absorbs fuel vapor.

The present invention provides, in one aspect, a baffle device configured to be disposed near an outlet of a fuel tank. The baffle device includes a fitting having an aperture therethrough and a first baffle. The first baffle includes a passageway in fluid communication with the aperture and at least one first baffle aperture configured to permit entry of fuel vapor into the passageway and exit of fuel vapor from the passageway. The baffle device also includes a second baffle overlying at least a portion of the first baffle aperture. The second baffle preferably includes a second baffle aperture that is misaligned with the first baffle aperture.

The present invention provides, in another aspect, a fuel tank assembly including a fuel tank having a wall at least partially defining a fuel-containing space, a fitting coupled to the wall, the fitting having an aperture therethrough, and a first baffle. The first baffle includes a passageway in fluid communication with the aperture and at least one first baffle aperture configured to permit entry of fuel vapor into the passageway and exit of fuel vapor from the passageway. The fuel tank assembly also includes a second baffle overlying at least a portion of the first baffle aperture.

The present invention provides, in yet another aspect, a baffle device including a fitting with an aperture therethrough. The aperture has an inlet end and an outlet end. The baffle device also includes a first baffle coupled to the fitting. The first baffle defines a first passageway in fluid communication with the inlet end of the aperture in the fitting. The first baffle includes a longitudinal slot. The baffle device further includes a second baffle coupled to the fitting. The second baffle defines a second passageway receiving at least a portion of the first baffle. The second baffle includes a longitudinal slot misaligned with the longitudinal slot in the first baffle. It is understood that the fitting, the aperture, and the baffles may be molded integrally as one piece with the wall of a plastic fuel tank. Alternatively, other constructions of the baffle device may incorporate both plastic and metal components that are separate from one another.

In each of the embodiments, the baffles preferably comprise one or more concentric, curved or arc-shaped members having slots in them or gaps between them to reduce the splashing of liquid fuel into or near the inlet end of the aperture in the fitting.

DETAILED DESCRIPTION

FIG. 1illustrates a fuel system10including a fuel tank assembly having a fuel tank14and a baffle device18coupled to the tank14. The fuel system10also includes a canister22containing activated carbon and a tube26fluidly connecting the canister22and the baffle device18. The canister22may be similar to the canister shown and described in U.S. Pat. No. 7,159,577, the entire content of which is incorporated herein by reference. The fuel system10may be used to provide fuel for internal combustion engines incorporated in outdoor power equipment (e.g., walk-behind lawn mowers, lawn tractors, generators, snow-throwers, and other non-hand held or hand-held outdoor power equipment).

With reference toFIGS. 1-9, the baffle device18includes a fitting30having an aperture34defining a central axis36. In the illustrated construction of the baffle device18, the aperture34is configured as a stepped aperture34, including an inlet end38and an outlet end42having different diameters. Specifically, the inlet end38of the aperture34has a diameter that is less than the diameter of the outlet end42of the aperture34to reduce the amount of liquid fuel that could flow through the aperture34and control the amount of vapor allowed to exit the tank14during refueling. In alternative constructions of the baffle device18, the inlet end38of the aperture34may have a diameter that is greater than the diameter of the outlet end42of the aperture34. Alternatively, the aperture34may have a substantially constant diameter from the inlet end38to the outlet end42. The fitting30preferably also includes a barb46configured to be inserted into the tube26that fluidly interconnects the baffle device18and the canister22or other ventilation system components. As shown inFIGS. 1,2, and9, the aperture34passes through the barb46.

With reference toFIGS. 1-9, the baffle device18also includes nested baffles50a,50b, each having a longitudinal axis coaxial with the central axis36, coupled to the fitting30. Alternatively, one or both of the nested baffles50a,50bmay be non-collinear with the central axis36. As shown inFIGS. 1-3and9, the baffle50aincludes respective ends54,58and defines a passageway62between the respective ends54,58of the baffle50a. Likewise, the baffle50bincludes respective ends66,70and defines a passageway74between the respective ends66,70of the baffle50b. The fitting30includes a cylindrical groove78, at least partially defined by an inner peripheral wall82, that is concentric with the aperture34(seeFIG. 3). The baffle50ais received within the groove78to fluidly communicate the passageway62and the aperture34in the fitting30. In the illustrated construction of the baffle device18, the outer diameter ODaof the baffle50aand the outer diameter of the groove78are sized to provide an interference fit between the end58of the baffle50aand the inner peripheral wall82(seeFIG. 7). In alternative constructions of the baffle device18, the baffle50amay be coupled to the fitting30in any of a number of different ways to fluidly communicate the passageway62of the baffle50aand the aperture34in the fitting30. In yet other alternative constructions of the baffle device18′, the baffle50amay be integrally formed as a single piece with the fitting30(seeFIG. 22).

With continued reference toFIGS. 1-3and9, the fitting30also includes a second groove86, at least partially defined by an inner peripheral wall94, that is concentric with the first groove78and the aperture34(seeFIG. 3). The baffle50bis received within the groove86, and at least a portion of the baffle50ais positioned within the passageway74of the baffle50b. In the illustrated construction of the baffle device18, the outer diameter ODb of the baffle50b(seeFIG. 5) and the outer diameter of the groove86are sized to provide an interference fit between the end70of the baffle50band the inner peripheral wall94. In alternative constructions of the baffle device18, the baffle50bmay be coupled to the fitting30in any of a number of different ways to receive at least a portion of the baffle50awithin the passageway74of the baffle50b. In yet other alternative constructions of the baffle device18′, the baffle50bmay be integrally formed as a single piece with the fitting30(seeFIG. 22). Further, the baffle50amay be coupled to the fitting30in any manner described above, and the baffle50bmay be directly coupled to the baffle50ain any number of different ways (e.g., fastening, welding, using adhesives, integrally forming, etc.). Likewise, the baffle50bmay be coupled to the fitting30in any manner described above, and the baffle50amay be directly coupled to the baffle50bin any number of different ways (e.g., fastening, welding, using adhesives, integrally forming, etc.).

With reference toFIGS. 1-9, the fitting30further includes a cylindrical outer portion90sized to provide an interference fit with a peripheral surface defining an aperture92in the fuel tank14(seeFIG. 1). The fitting30may also be welded to the fuel tank14or adhesives may be utilized to further secure the baffle device18to the fuel tank14. Alternatively, at least a portion of the baffle device18′ (e.g., the fitting30) may be integrally formed with a portion of the fuel tank14(e.g., a wall of the fuel tank14that at least partially defines a fuel-containing space) (seeFIG. 22). Further, the respective baffles50a,50bmay be integrally formed as a single piece with the fitting30, or the baffles50a,50bmay be integrally formed as a single piece with the fitting30and a portion of the fuel tank14(seeFIG. 22). As a further alternative, other structure (e.g., a grommet) may be utilized to secure the baffle device18to the fuel tank14.

With reference toFIG. 2, the baffle50ais sized such that a ratio of the length La of the baffle50ato the inner diameter IDa of the baffle50ais at least about 3:1. Generally, increasing the ratio of the length La of the baffle50ato the inner diameter IDa of the baffle50aalso steepens the angle at which fuel within the baffle50aor fuel below the baffle50amust splash to reach the aperture34through the passageway62. With continued reference toFIG. 2, the baffle50bis sized such that a ratio of the length Lb of the baffle50bto the inner diameter IDb of the baffle50bis at least about 2:1.

With reference toFIGS. 3 and 4, the baffle50aincludes a first baffle aperture preferably configured as a longitudinal slot98extending between the respective ends54,58of the baffle50a. In the illustrated construction of the baffle device18, the width Wa of the slot98is between about one-fourth of an inch and about one-sixteenth of an inch (seeFIG. 7). The baffle50balso includes a second baffle aperture preferably configured as a longitudinal slot102extending between the respective ends66,70of the baffle50b. In the illustrated construction of the baffle device18, the width Wb of the slot102is at least about one-sixteenth of an inch (seeFIG. 5), and is about equal to the width Wa of the slot98. The widths Wa,Wb of the respective slots98,102are sized small enough to reduce the amount of liquid fuel entering the passageway62through the baffles50a,50bin a direction substantially transverse to the central axis36of the aperture34, yet large enough to allow sufficient vapor venting from the fuel tank14at high fill levels and tilt angles of fuel in the fuel tank14. The widths Wa,Wb of the respective slots98,102are also sized large enough to allow substantially uninhibited movement of air through the slots98,102to allow replacement air to enter the fuel tank14when the fill level in the tank14decreases. Further, the widths Wa,Wb of the respective slots98,102are sized large enough to substantially prevent liquid fuel in the fuel tank14from coalescing or bridging the widths Wa,Wb of the respective slots98,102due to the effects of surface tension, viscosity, and surface energy that may otherwise inhibit the flow of vapor through the slots98,102. Alternatively, each of the baffles50a,50bmay include one or more longitudinally-spaced apertures rather than the slots98,102.

With reference toFIGS. 3,4, and8, the respective slots98,102of the baffles50a,50bare misaligned with one another such that the slot98in the baffle50ais not in facing relationship with the slot102in the baffle50bto provide a straight-line path through the baffles50a,50bin a direction substantially transverse to the central axis36of the aperture34. Specifically, in the illustrated construction of the baffle device18, the slot98in the baffle50ais misaligned with the slot102in the baffle50bby about 180 degrees. In alternative constructions of the baffle device18, the slot98in the baffle50amay be misaligned with the slot102in the baffle50bby at least about 30 degrees. In yet other alternative constructions of the baffle device18, the baffle50bneed not comprise a complete cylinder, but rather may comprise a portion of a cylinder (i.e., a curved or an arc-shaped portion) that is sufficiently long enough (e.g., about 60 or more degrees) to at least partially shield the slot98in the baffle50a.

With reference toFIG. 2, the fitting30provides a gap G between the outer diameter ODa of the baffle50aand the inner diameter IDb of the baffle50bthrough which fuel vapor must flow to reach the passageway62of the baffle50aand the aperture34in the fitting30. The gap G is sized large enough for the same reasons as discussed above with respect to the widths Wa,Wb of the respective slots98,102, i.e., to substantially prevent liquid fuel from adhering or coalescing between the outer wall of the baffle50aand the inner wall of the baffle50bdue to the effects of surface tension, viscosity, and surface energy that may otherwise inhibit the flow of vapor through the gap G.

With continued reference toFIG. 2, the end54of the baffle50ais spaced from the end66of the baffle50bby a length dimension ΔL along the central axis36. Spacing the respective ends54,66of the baffles50a,50bin this manner substantially reduces coalescence of fuel between the ends54,66of the respective baffles50a,50b. The length dimension ΔL is sized large enough for the same reasons as discussed above with respect to the widths Wa,Wb of the respective slots98,102, i.e., to substantially prevent liquid fuel from adhering or coalescing between the ends54,66of the respective baffles50a,50bdue to the effects of surface tension, viscosity, and surface energy that may otherwise inhibit the flow of vapor between the baffles50a,50band through the gap G. In the illustrated construction of the baffle device18, the length dimension ΔL is greater than the gap G. Alternative constructions of the baffle device18in which the length dimension ΔL is decreased may also include an increased gap G to provide sufficient spacing between the ends54,66of the respective baffles50a,50bto substantially prevent liquid fuel from coalescing between the ends54,66of the respective baffles50a,50b. Alternative constructions of the baffle device18in which the gap G is decreased may also include an increased length dimension ΔL to provide sufficient spacing between the ends54,66of the respective baffles50a,50bto substantially prevent liquid fuel from coalescing between the ends54,66of the respective baffles50a,50b. In yet other alternative constructions, the baffle device18may, however, incorporate a length dimension ΔL at least as large as the gap G.

With reference toFIG. 1, assuming the level of fuel within the tank14is below the end54of the baffle50a, fuel vapor in the tank14may exit the tank14by flowing directly through the passageway62of the baffle50a(upwardly as shown inFIG. 1) and through the aperture34in the fitting30to reach the canister22via the tube26. The nested baffles50a,50b, however, reduce the amount of liquid fuel, as it is splashed or sloshed against the walls of the fuel tank14, that reaches the aperture34in the fitting30and the canister22. Specifically, the misaligned slots98,102in the baffles50a,50bprovide a tortuous path that reduces the amount of liquid fuel that splashes through the baffles50a,50b, in a direction substantially transverse to the central axis36, and into the passageway62of the baffle50aor the aperture34in the fitting30.

Should the fuel tank14be filled such that the fuel level is above the lower ends54,66of the respective baffles50a,50b, fuel vapor in the tank14may exit the tank14by flowing through the tortuous path created by the misaligned slots98,102in the baffles50a,50b, in a direction substantially transverse to the central axis36. Upon reaching the passageway62of the baffle50a, the fuel vapor may flow through the aperture34in the fitting30to reach the canister22via the tube26. However, the nested baffles50a,50breduce the amount of liquid fuel, as it is splashed or sloshed against the walls of the fuel tank14, that reaches the aperture34in the fitting30in substantially the same manner as described above when the level of fuel in the fuel tank14is below the respective lower ends54,66of the baffles50a,50b.

FIGS. 10-15illustrate a second construction of a baffle device106configured for use with the fuel tank14, the tube26, and the canister22ofFIG. 1. Like the baffle device18, the baffle device106includes a fitting108having an aperture112therethrough and a cylindrical outer portion113. With reference toFIGS. 10-12, the baffle device106also includes a spiraled baffle110having respective ends114,118and defining a passageway122between the respective ends114,118of the baffle110. The spiraled baffle110includes nested windings126a,126bthat define a spiraled tortuous path about a central axis120of the aperture112(seeFIG. 12). In the illustrated construction of the baffle device106, the interior winding126ais engaged with the cylindrical outer portion113of the fitting108by an interference fit to secure the baffle110to the fitting108(seeFIG. 13). In alternative constructions of the baffle device106, the baffle110may be coupled to the fitting108in any of a number of different ways to fluidly communicate the passageway122of the baffle110and the aperture112in the fitting106.

As previously stated, the baffle device106may be utilized with the fuel tank14, the tube26, and the canister22ofFIG. 1. Assuming the level of fuel within the tank14is below the end114of the baffle110, fuel vapor in the tank14may exit the tank14by flowing directly through the passageway122of the baffle110and through the aperture112in the fitting108to reach the canister22via the tube26. The nested windings126a,126b, however, reduce the amount of liquid fuel, as it is splashed or sloshed against the walls of the fuel tank14, that reaches the aperture112in the fitting108and the canister22. Specifically, the nested windings126a,126bprovide a tortuous path that reduces the amount of liquid fuel that splashes through the nested windings126a,126bof the baffle110, in a direction substantially transverse to the central axis120, and reaches the passageway122of the baffle110or the aperture112in the fitting108.

Should the fuel tank14be filled such that the fuel level is above the lower end114of the baffle110, fuel vapor in the tank14may exit the tank14by flowing through the tortuous path created by the nested windings126a,126balong a path spiraled about the central axis120. Upon reaching the passageway122of the baffle110, the fuel vapor may flow through the aperture112in the fitting108to reach the canister22via the tube26. However, the nested windings126a,126breduce the amount of liquid fuel, as it is splashed or sloshed against the walls of the fuel tank14, that reaches the aperture112in the fitting108in substantially the same manner as described above when the level of fuel in the fuel tank14is below the lower end114of the baffle110.

FIGS. 16-21illustrate a third construction of a baffle device130configured for use with the fuel tank14, the tube26, and the canister22ofFIG. 1. Like the baffle device18, the baffle device130includes a fitting132having a stepped aperture133therethrough, with an inlet end135and an outlet end136, and a cylindrical outer portion137(seeFIG. 18). With reference toFIGS. 16,17, and20, the baffle device130includes a two-piece baffle134including opposed J-shaped baffles138defining a passageway142between the respective baffles138. Each J-shaped or other curved baffle138includes a substantially curved or cylindrical portion146and a straight portion150extending from the curved or cylindrical portion146. In the illustrated construction of the baffle device130, the respective arced, curved, or cylindrical portions146of the J-shaped baffles138engage the cylindrical outer portion137of the fitting132by an interference fit to secure the respective baffles138to the fitting132(seeFIG. 20). In alternative constructions of the baffle device130, the two-piece baffle134may be coupled to the fitting132in any of a number of different ways to fluidly communicate the passageway142defined by the baffles138and the aperture133in the fitting132.

As previously stated, the baffle device130may be utilized with the fuel tank14, the tube26, and the canister22ofFIG. 1. Assuming the level of fuel within the tank14is below the lower end of the two-piece baffle134, fuel vapor in the tank14may exit the tank14by flowing directly through the passageway142defined between the baffles138and through the aperture133in the fitting132to reach the canister22via the tube26. The curved or cylindrical portions146of the baffles138and the straight portions150of the baffles138, however, reduce the amount of liquid fuel, as it is splashed or sloshed against the walls of the fuel tank14, that reaches the aperture133in the fitting132and the canister22. Specifically, the J-shaped baffles138provide tortuous paths between the curved or cylindrical portion146of one baffle138and the straight portion150of the other baffle138to reduce the amount of liquid fuel that splashes through the two-piece baffle134, in a direction substantially transverse to a central axis140of the aperture133(seeFIG. 16), and reaches the passageway142defined between the baffles138or the aperture133in the fitting132.

Should the fuel tank14be filled such that the fuel level is above the lower end of the two-piece baffle134, fuel vapor in the tank14may exit the tank14by flowing through the tortuous paths created between the curved or cylindrical portion146of one baffle138and the straight portion150of the other baffle138. Upon reaching the passageway142defined between the respective baffles138, the fuel vapor may flow through the aperture133in the fitting132to reach the canister22via the tube26. However, the two-piece baffle134reduces the amount of liquid fuel, as it is splashed or sloshed against the walls of the fuel tank14, that reaches the aperture133in the fitting132in substantially the same manner as described above when the level of fuel in the fuel tank14is below the lower end of the two-piece baffle134.