FUEL TANK VENT HEATER FIELD

[0001] The presently addressed technology relates generally to combustion engine powered land vehicles that have vented fuel tanks. More specifically, the present disclosure relates to a fuel tank vent warmer that utilizes return fuel from the engine to warm the fuel tank vent.

BACKGROUND

[0002] Motor vehicles commonly have fuel tanks with vents. The fuel tank vents have a variety of functional purposes, a few of which include keeping the fuel tank at a proper working pressure, venting off hydrocarbon emissions, and venting off moisture that accumulates in the fuel tank. In some systems the vent releases vapors to the atmosphere while in others the vent runs back to the engine where hydrocarbon emissions and moisture are burned/vaporized before being released in to the atmosphere. [0003] Motor vehicles must operate in a wide variety of conditions; one being, extreme cold. Cold weather can have an adverse effect on motor vehicle systems regardless of whether the system is of an electrical, hydraulic, or mechanical type. In many cases, additional energy is required to maintain proper functionality of the affected motor vehicle system, particularly through the provision of heat.

[0004] A motor vehicle's fuel system is a common victim of very cold temperatures. Frozen fuel, frozen fuel lines, cold combustion air, and frozen fuel tank vents are just a few of the problems that a fuel system encounters in cold weather. [0005] When sufficiently cold temperatures prevail, moisture venting from the fuel tank can freeze in the vent. If enough moisture freezes inside the vent, the vent will

freeze over and neither pressure nor moisture can escape. In vehicles having more than one fuel tank a blocked vent is likely to result in a pressure build in the blocked tank that forces the fuel from that pressurized tank to the still-vented tank. In cold temperatures semi-truck drivers commonly fill the available fuel tanks. If a pressure differential exists between the fuel tanks, fuel from the pressured tank will be forced into the unpressurized tank. If the unpressurized fuel tank does not have sufficient excess volume (is empty enough) to hold the fuel flowing from the pressurized tank, fuel will be forced out of the unpressurized tank through the fuel tank vent. The obvious detriment of such a leakage is not only the loss of the fuel itself, but also the dangers and pollution that uncontained fuel present. Further, if the vent on each of the fuel tanks is frozen closed a resulting build-up in pressure will cause the engine to stall. Further still, if an excess amount of moisture builds up in the fuel tank and mixes with the fuel the engine may stall. [0006] In the past, the problem of fixing frozen fuel tank vents has been time consuming. When a fuel tank vent was frozen, the vehicle operator had only limited options. The operator could pull the vehicle over, brave the harsh elements, and attempt to manually warm the fuel vent with a heat source. This method is dangerous, time consuming, and, at times, not even an option because of other environmental conditions. Initially, the operator has to pull the vehicle over, prepare for the extreme conditions, and must also have a safe heat source to manually warm the vent. A safe heat source; i.e., a source with no open flame, is required to prevent an explosion when working with the pressurized tank of combustible fuel. Moreover, the chances that the vent will refreeze are high, unless the environmental conditions have changed, causing the operator to have to repeat the thawing procedures and resulting in more downtime.

[0007] If parking and thawing the fuel tank vent along the roadside is not an option, the operator will then need to park the vehicle in a warm place such as a garage and allow the vent to thaw - - and such garages are rarely available when needed. Moreover, the problematic freezing of the vent often occurs quickly and there is little opportunity for an operator to find an adequately heated facility. Commonly, an operator will be driving through desolate areas in the extreme cold and will have no option except to pull over and wait for help. If the engine stalls or the operator turns off the vehicle to prevent gas from spilling out, the operator will face extremely cold temperatures with the possibility of no heat source. Further, these extreme conditions make the possibility of receiving outside roadside assistance speculative at best and not comfortable to rely upon. [0008] Efficiency is always on the minds of vehicle operators and none want to waste fuel or loose driving time. Therefore, the present disclosure appreciates the need to have a simple, effective, and low cost method and apparatus for preventing fuel tank vent freezing in cold temperatures.

SUMMARY

[0009] Accordingly, there is a need for a simple, effective, and low cost apparatus that prevents the fuel tank vent from freezing. According to the teachings of the present invention, a fuel tank vent heater is provided that warms the vent and prevents its freezing. The vent heater is located proximate the vent, preferably close thereabout, and can be suitably connected to the vent, the supporting fuel tank, or an otherwise nearby structure of the vehicle. As described herein, the vent heater has a body of some mass through which fluid channels course. Advantageously, the body of the heater has an interior cavity configured to fit about the exterior of the vent. A warm fluid is flowed

through the channels resulting in a heating of the body and ultimately the proximate vent. In a preferred embodiment, the warmed fluid is return fuel from the engine. [0010] In one development or version of the vent heating arrangement, the heater is an apparatus that can be implemented on an existing or new vehicle. The body of the heater comprises a thermally conductive material for transferring energy to the fuel tank vent. A fluid channel is defined by the body of the heater, and further, the fluid channel can be defined on or within the body of the heater. Generally, the fluid channel comprises an inlet and an outlet; the inlet allowing a warmed fluid to flow into the fluid channel and the outlet allowing the warmed fluid to flow out of the fluid channel. The heater can also be constructed to fit about the fuel tank vent by creating an interior vent cavity in the body of the heater. The inside of the interior vent cavity can be designed to substantially conform, in whole or in part, to the shape of the fuel tank vent. If the fit is sufficiently tight, it can serve to resist unintended disengagement of the heater from the fuel tank vent.

[0011] In one development or version of the vent heating arrangement, the heater, vent and the fuel tank are unitarily constructed. In this embodiment, the vent heater and fuel tank are of one-piece construction and the vent is integrally formed through the body of the heater.

[0012] In operation, fuel flows from the fuel tank to the engine where a combustion reaction takes place. Vehicle engines are commonly fed excess fuel to prevent engine starving, and upon combustion, a portion of fuel is left unreacted and leaves the engine as warmed fuel. This warmed fuel is warmer that the fuel in the tank or the supply line. The warmed fuel is conducted to the vent heater via a return fuel line where it is then

circulated through the fluid channel(s) of the heater body. While the warmed fuel is flowing through the fluid channel, the body of the vent heater takes up heat out of the fuel and conducts it over to the vent. After exiting the vent heater, the warmed fuel flows into the fuel tank where it mixes with the fuel present in the tank.

[0013] Other aspects of the presently disclosed technological advancements in fuel tank vent heating methods and arrangements will be appreciated by those persons skilled in the art from the detailed description presented herein.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a perspective view of a fuel tank vent heater attached to a fuel tank in accordance with the teachings of the present disclosure;

[0015] FIG. 2a is a perspective top view of a vent heater configured in accordance with the teachings of the present disclosure;

[0016] FIG. 2b is a perspective bottom view of the vent heater configured in accordance with the teachings of the present disclosure;

[0017] FIG. 2c is a perspective cut-away bottom view of the vent heater of FIG. 2b taken along section line 2c-2c;

[0018] FIG. 2d is a perspective cut-away bottom view of the vent heater of FIG. 2b taken along section line 2d-2d;

[0019] FIG. 2e is an end view of the vent heater of FIG. 2b and showing some internal features in phantom;

[0020] FIG. 3a is a perspective bottom view of a vent heater configured in accordance with the teachings of the present disclosure;

[0021] FIG. 3b is a perspective cut-away bottom view of the vent heater of FIG. 3a taken along section line 3b-3b;

[0022] FIG. 3c is a perspective cut-away bottom view of the vent heater of FIG. 3a taken along section line 3c-3c;

[0023] FIG. 4a is a perspective bottom view of a vent heater configured in accordance with the teachings of the present disclosure;

[0024] FIG. 4b is a perspective cut-away bottom view of the vent heater of FIG. 4a taken along section line 4b-4b;

[0025] FIG. 4c is a perspective cut-away bottom view of the vent heater of FIG. 4a taken along section line 4c-4c;

[0026] FIG. 5a is a perspective bottom view of a vent heater configured in accordance with the teachings of the present disclosure;

[0027] FIG. 5b is a perspective cut-away bottom view of the vent heater of FIG. 5 a taken along section line 5b-5b;

[0028] FIG. 5c is a perspective cut-away bottom view of the vent heater of FIG. 5a taken along section line 5c-5c;

[0029] FIG. 6a is a cross-sectional view of the vent heater of FIG. 2b taken along section line 6a-6a;

[0030] FIG. 6b is a cross-sectional view of the vent heater of FIG. 3 a taken along section line 6b-6b; and

[0031] FIG. 6c is a cross-sectional view of the vent heater of FIG. 4a taken along section line 6c-6c.

[0032] FIG. 6d is a cross-sectional view of the vent heater of FIG. 5 a taken along section line 6d-6d.

DETAILED DESCRIPTION

[0033] Referring to FIG. 1, a vent heater 2 configured according to the presently disclosed teachings is shown. Vent heater 2 is attached to a fuel tank 4 and is positioned about vent 6. In motor vehicles, a fuel supply line (not shown) is provided to transport fuel from fuel tank 4 to an engine (not shown). In certain motor vehicles, excess fuel is fed to the engine to prevent starving and is warmed in the presence of the combustion reaction in the engine. Excess fuel that is not used in the combustion reaction is returned to fuel tank 4 via a return line 8 and 15. Return line 8 transports the warmed fuel from the engine to vent heater 2, and return line 15 transports the fuel from vent heater 2 into fuel tank 4. The warmed excess fuel warms the body 10 of vent heater 2, which in turn warms vent 6. The heat transferred to vent 6 prevents vent 6 from freezing. [0034] Referring to FIGS. 2a-2e, an exemplary embodiment of the vent heater 2a is presented. Vent heater 2a has a body 10a having an aperture 12a for fitting about vent 6 and vent hose 14 (see FIG. 1). Body 10a can be composed of any suitable material or combination of materials that will transfer thermal energy. Metals are a preferred material, with aluminum being the most preferred. Body 10a further has a fluid channel 16a having a first fluid aperture (inlet) 18a and a second fluid aperture (outlet) 20a. First fluid aperture 18a presents an opening in body 10a where warmed fuel can flow through fluid channel 16a. Second fluid aperture 20a presents an opening in body 10a where warmed fuel can flow from fluid channel 16a to fuel tank 4.

[0035] Referring to FIGS. 3a-3c, another exemplary embodiment in the form of vent heater 2b is presented. Vent heater 2b has a body 10b having an aperture 12b for fitting about vent 6 and vent hose 14 (see FIG. 1). Body 10b can be composed of any suitable material or combination of materials that will transfer thermal energy. Metals are a preferred material, with aluminum being the most preferred. Body 10b further has a fluid channel 16b having a first fluid aperture 18b, and a second fluid aperture 20b. First fluid aperture 18b presents an opening in body 10b where warmed fuel can flow through fluid channel 16b. Second fluid aperture 20b presents an opening in body 10b where warmed fuel can flow from fluid channel 16b to fuel tank 4.

[0036] Referring to FIGS. 4a-4c, yet another exemplary embodiment in the form of vent heater 2c is presented. Vent heater 2c has a body 10c having an aperture 12c for fitting about vent 6 and vent hose 14 (see FIG. 1). Body 10c can be composed of any suitable material or combination of materials that will transfer thermal energy. Metals are a preferred material, with aluminum being the most preferred. Body 10c further has a fluid channel 16c having a first fluid aperture 18c, and a second fluid aperture 20c. First fluid aperture 18c presents an opening in body 10c where warmed fuel can flow through fluid channel 16c. Second fluid aperture 20c presents an opening in body 10c where warmed fuel can flow from fluid channel 16c to fuel tank 4.

[0037] Referring to FIGS. 5a-5c, yet another exemplary embodiment in the form of vent heater 2d is presented. Vent heater 2d has a body 1Od having an aperture 12d for fitting about vent 6 and vent hose 14 (see FIG. 1). Body 1Od can be composed of any suitable material or combination of materials that will transfer thermal energy. Metals are a preferred material, with aluminum being the most preferred. Body 1Od further has a

fluid channel 16d having a first fluid aperture 18d, and a second fluid aperture 2Od. First fluid aperture 18d presents an opening in body 1Od where warmed fuel can flow through fluid channel 16d. Second fluid aperture 2Od presents an opening in body 1Od where warmed fuel can flow from fluid channel 16d to fuel tank 4.

[0038] FIGS. 6a-6d provide for cross-sectional views of vent heater 2a, 2b, 2c, and

2d respectively. FIGS. 6a-6d illustrate cut-away sections of fluid channel 16a, 16b, 16c, and 16d along section lines 6a-6a, 6b-6b, 6c-6c, and 6d-6d.

[0039] Other embodiments of the disclosed fuel tank vent heater 2 can include a hollow body that contains a conduit. A thermally conducive fluid, gel, or other material can be placed into the hollow body, thereby immersing the conduit in a thermally conductive material. Then, if the thermally conductive material needs to be sealed within the hollow body, that step could be performed.

[0040] The vent heater 2 can be physically attached to the fuel tank 4 utilizing any suitable means and method as long as it allows for the transfer of heat from vent heater 2 to vent 6. In at least one embodiment, the vent heater 2 is constructed to fit onto existing fuel tank vents 6.

[0041] Alternative embodiments of the fuel tank vent heater 2 are disclosed in the accompanying figures. Different versions of the vent heater 2 are designated in the figures as 2a, 2b, 2c, 2d and each comprises an integral attachment mechanism having a respective first threaded integral bore 24a, 24b, 24c, 24d and a respective second threaded integral bore 26a, 26b, 26c, 26d for easily attaching the vent heater 2a, 2b, 2c,

2d to an existing fuel tank vent by inserting and tightening connective bolts through respective bores 24, 26, to clamp vent heater 2a, 2b, 2c, 2d to vent 6. In one preferred

embodiment first threaded integral bore 24a, 24b, 24c, 24d and second threaded integral bore 26a, 26b, 26c, 26d are aligned perpendicular to each other. In another preferred embodiment a single threaded integral bore is used as the attachment mechanism. It is further contemplated that the vent heater 2 can be attached using any suitable mechanism including spring latches, magnets, glue, epoxy, welding, and the like.

[0042] In another embodiment, the aperture or recess 12 in the body of the heater 2 in which the vent 6 is located is configured to fit snuggly about the vent 6 with an interference fit therebetween that resists disengagement of the heater 2 from the vent 6.

The aperture 12 is constructed to compliment the shape of the vent and to create a snug fit about the fuel tank vent.

[0043] In another preferred embodiment, the vent heater 2 and fuel tank 4 can be constructed as a unitary structure.

[0044] The vent heater 2 can be created in a variety of ways. Three examples include machining, casting, and building from suitably configured parts.

[0045] In a first example, the vent heater 2 can be produced by machining a single piece of material. The machining can take place by hand or can be done by a computer numerically controlled (CNC) milling machine. In one embodiment, the process requires the machining of three interconnected bores. As seen in FIGS. 2a-2e, a single bore 100 is created in body 10a. Next, two similar bores 102, 104 are created and intersect bore 100.

Single bore 100 must then be plugged at each end; this can be accomplished in a variety of ways, an example of which is by threading each end of bore 100, and screwing in a plug. Likewise, each end of bore 100 can be permanently filled; e.g., with a weld or an epoxy. As shown in FIG. 2c, bore 100 is seen to travel through the entire body 10a; when

using multiple bores it is only necessary that all the bores interconnect to form a fluid channel. While creating a fluid channel that allows fluid to travel around vent 6 in a u- shaped pattern is a preferred construction, it is within the scope of the invention to have a single linear fluid channel that would require only a single bore to be created in body 10a, or further, two bores that interconnect within body 10a.

[0046] The disclosed designs can also be produced by machining two separate pieces, and then connecting those pieces together. Preferably, the two separate pieces would each be comprised of one-half of the fluid channel, wherein the fluid channels would be mirror images of each other. One could also machine one-half of the material and use the complementary half as a lid; this may form what resembles a u-shaped channel. The two halves would be superimposed and connected together using common metal fabrication methods. To further facilitate assembly, it would be common for a machinist to place recesses on one of the halves and complimentary protrusions on the other half. The two halves would fit snugly together and could be attached using a single bolt or clamp. The two halves could also be permanently attached using an epoxy or simply welding the halves together.

[0047] Vent heaters according to the present disclosure can also be made using common casting techniques. Casting is a process by which a fluid melt is introduced into a mold, allowed to cool in the shape of the form, and then ejected to make a fabricated part or casing.

[0048] A common casting technique for creating patterns in metal castings is the lost- foam process. The lost-foam casting process uses foam within the casting mold to form patterns that would difficult, if not impossible to form by traditional casting techniques.

FIGS. 3, 4 and 5 illustrate embodiments of the vent heater 2b, 2c, 2d that have been formed by a lost-foam molding process. The lost foam process allows for the construction of a smooth U-shaped channel running through body 10a of vent heater 2b,

2c, 2d. The lost-foam casting process allows the construction of a myriad of fluid channel patterns in the body 10 that fosters the transfer of heat from the fluid to the body 10.

[0049] In another common casting technique, the casting process produces two separate castings that can be combined. Much like the machining process described above, castmg multiple pieces requires two complimentary pieces to be cast that can subsequently be attached to form the vent heater. There are many casting techniques available to create such castings.

[0050] The vent heater can also be produced by manually piecing together suitably configured component parts. An individual could create a hollow body into which a conduit is arranged so as to create a fluid channel throughout the hollow body and in turn, the hollow body can be filled with thermally conductive matter, and, if necessary, sealed to contain the matter.

[0051] It is also contemplated that the vent heater 2 can include insulation in places where heat loss would otherwise occur. For example, insulation can be placed between the vent heater 2 and the fuel tank 4 to avoid heat loss to the tank 4. Insulation can also be placed around vent heater 2, return fuel line 8, 15, and vent hose 14 to avoid heat loss to the ambient environment.

[0052] This detailed description is set forth only for the purposes of illustrating examples of the presently disclosed method and arrangement for providing a fuel tank

vent heater and should not be considered to limit the scope of the patent claims in anyway. Clearly, numerous additions, substitutions, and other modifications can be made to the examples without departing from the scope of the invention which is defined exclusively by the patent claims.