U.S. patent application number 12/032895 was filed with the patent office on 2009-08-20 for system and method for inhibiting vaporization from liquids.
Invention is credited to Eric B. Hudak, Dale D. Snyder, Nathan R. Vogt.
Application Number | 20090206081 12/032895 |
Document ID | / |
Family ID | 40718530 |
Filed Date | 2009-08-20 |
United States Patent
Application |
20090206081 |
Kind Code |
A1 |
Snyder; Dale D. ; et
al. |
August 20, 2009 |
System and Method for Inhibiting Vaporization from Liquids
Abstract
A liquid tank such as a liquid fuel tank, as well as a method of
operating such a tank and a structure for implementation in such a
tank, are disclosed. In at least one embodiment, the liquid tank is
a liquid fuel tank that includes a housing have an inner chamber
capable of containing liquid fuel as well as an air space above an
upper surface of the liquid fuel, and a floating member included
within the inner chamber, where the floating member is configured
to float proximate the upper surface of the liquid fuel when the
liquid fuel is present within the inner chamber. The floating
member includes at least one tapered surface, and the floating
member covers a majority of the upper surface of the liquid fuel,
whereby the liquid fuel evaporates to a lesser degree than would
occur if the floating member was absent.
Inventors: |
Snyder; Dale D.; (Oshkosh,
WI) ; Vogt; Nathan R.; (Manchester, NH) ;
Hudak; Eric B.; (Sheboygan, WI) |
Correspondence
Address: |
WHYTE HIRSCHBOECK DUDEK S C;INTELLECTUAL PROPERTY DEPARTMENT
555 EAST WELLS STREET, SUITE 1900
MILWAUKEE
WI
53202
US
|
Family ID: |
40718530 |
Appl. No.: |
12/032895 |
Filed: |
February 18, 2008 |
Current U.S.
Class: |
220/217 |
Current CPC
Class: |
B60K 15/077 20130101;
B60K 2015/0772 20130101; B60K 15/03 20130101 |
Class at
Publication: |
220/217 |
International
Class: |
B65D 88/48 20060101
B65D088/48 |
Claims
1. A liquid fuel tank comprising: a housing have an inner chamber
capable of containing liquid fuel as well as an air space above an
upper surface of the liquid fuel; and a floating member included
within the inner chamber, wherein the floating member is configured
to float proximate the upper surface of the liquid fuel when the
liquid fuel is present within the inner chamber, wherein the
floating member includes at least one tapered surface, and wherein
the floating member covers a majority of the upper surface of the
liquid fuel, whereby the liquid fuel evaporates to a lesser degree
than would occur if the floating member was absent.
2. The liquid fuel tank of claim 1, wherein the floating member is
made of a plastic material.
3. The liquid fuel tank of claim 1, wherein the floating member is
made of a metal material.
4. The liquid fuel tank of claim 1, wherein the floating member
covers more than three-quarters of the upper surface of the liquid
fuel.
5. The liquid fuel tank of claim 1, wherein the tank is
substantially circular in cross-section.
6. The liquid fuel tank of claim 1, wherein the floating member has
a tapered top and includes a substantially circular base.
7. The liquid fuel tank of claim 6, wherein the tank is
substantially circular in cross-section, and wherein an annular
portion of the upper surface remains uncovered by the floating
member.
8. The liquid fuel tank of claim 1, wherein the floating member
includes first and second tapered surfaces that are positioned
back-to-back.
9. The liquid fuel tank of claim 8, wherein a rim around a junction
between the first and second tapered surfaces is configured to
remain slightly below a portion of the upper surface of the liquid
fuel when the floating member is floating within the liquid
fuel.
10. An internal combustion engine comprising the liquid fuel tank
of claim 1.
11. The internal combustion engine of claim 10, wherein the
internal combustion engine is a small off-road engine (SORE).
12. A lawn mower comprising the internal combustion engine of claim
10.
13. The liquid fuel tank of claim 1, wherein a fuel input port is
located above the floating member and wherein, when the liquid fuel
condenses upon the floating member or is provided into the fuel
tank via the fuel input port, the fuel streams down the at least
one tapered surface.
14. The liquid fuel tank of claim 1, wherein the floating member
includes at least one hollow interior region.
15. The liquid fuel tank of claim 14, wherein the floating member
is a hollow cone having an orifice along a base of the cone.
16. The liquid fuel tank of claim 1, further comprising an output
port by which the fuel can exit the inner chamber.
17. A liquid tank comprising: a portion of a liquid capable of
evaporation; an interior region within which the portion of the
liquid is positioned, and further within which is located an air
space above an upper surface of the portion of the liquid; and
means for covering at least a majority of the upper surface,
wherein a covered part of the upper surface is separated from the
air space, whereby the evaporation of the liquid occurs at a
reduced level due to the means for covering.
18. The liquid tank of claim 17, wherein the liquid is selected
from the group consisting of gasoline, diesel fuel, kerosene, crude
oil, another petroleum-based fuel, ethanol-based fuels, a mineral
oil, acetone, benzene, another organic fluid, and another volatile
fluid.
19. The liquid tank of claim 17, wherein the means for covering
includes at least one tapered surface.
20. The liquid tank of claim 19, wherein the means for covering
includes at least one substantially cone-shaped surface.
21. A method of operating a fuel tank, the method comprising:
filling the fuel tank with an amount of a liquid fuel, wherein an
air space remains above an upper surface of the liquid fuel; and
floating a structure within the fuel tank, wherein the structure
floats proximate the upper surface of the liquid fuel and extends
upward out of the liquid fuel above the upper surface, wherein the
structure includes a tapered surface such that a cross-sectional
area of the structure becomes increasingly smaller as one proceeds
upward along the structure away from the upper surface, and wherein
a portion of the upper surface is separated from the air space due
to the structure.
22. The method of claim 21, further comprising: receiving the
liquid fuel atop the structure, and allowing the liquid fuel to run
down the tapered surface of the structure and arrive at the upper
surface.
23. The method of claim 21, wherein the tapered surface includes at
least one substantially cone-shaped portion.
24. A structure for implementation in a liquid fuel tank, the
structure comprising: at least one tapered surface, wherein the
structure is configured to float along an upper surface of liquid
fuel within the liquid fuel tank and reduce an exposed area of the
upper surface so as to reduce evaporation of the liquid fuel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
FIELD OF THE INVENTION
[0001] The present invention relates to internal combustion engines
and, more particularly, relates to fuel storage and delivery
systems and methods for use in internal combustion engines.
BACKGROUND OF THE INVENTION
[0002] Fuel tanks are typically employed in internal combustion
engines to store fuels such as gasoline, diesel fuel and other
types of liquid fuels that are used by the engines. When situated
within a fuel tank, certain amounts of a liquid fuel typically
become vaporized, particularly when temperatures within the tanks
rise, when the tanks experience high levels of jostling, and/or
when the volume within the tank unoccupied by fuel (and filled with
air) becomes large. The vaporization of fuel continues even during
the normal course of storage of the fuel within the fuel tank.
[0003] Fuel vapors emanating from the fuel tanks of internal
combustion engines are one of the main contributors to evaporative
emissions from such engines. Such emissions from fuel tanks can
occur particularly when passage(s) are formed that link the
interior of the fuel tank with the outside atmosphere, for example,
for venting purposes as well as when refueling occurs. Because fuel
vapors can contribute to ozone and urban smog and otherwise
negatively impact the environment, increasingly it is desired that
these evaporative emissions from fuel tanks be entirely eliminated
or at least reduced. In particular, legislation has recently been
enacted (or is in the process of being enacted) in various
jurisdictions such as California placing restrictions on the
evaporative emissions of Small Off Road Engines (SORE), such as
those employed in various small off-road vehicles and other small
vehicles that are used to perform various functions in relation to
the environment, for example, lawn mowers and snow blowers.
[0004] For at least these reasons, therefore, it would be
advantageous if an improved system/device and/or method could be
created to prevent or reduce evaporative emissions from fuel tanks,
such as the fuel tanks of internal combustion engines including,
for example, SORE engines.
SUMMARY OF THE INVENTION
[0005] The present inventors have recognized the desirability of
reducing evaporative emissions from fuel tanks and further have
recognized that such emissions can be reduced by reducing the
surface area of the fuel within a fuel tank that is exposed to air
within the fuel tank, so as to reduce the amount of fuel that is
vaporized within fuel tanks. Further, the present inventors have
recognized that, in at least some embodiments, such goals can be
achieved by employing one or more cone-shaped or double-cone-shaped
structures that float within the fuel and at the same time reduce
the overall surface area of the fuel that is exposed to air within
the fuel tank. Such structures can be particularly advantageous in
that the structures naturally orient themselves in a manner that
results in maximum reduction of the exposed fuel surface.
[0006] In at least some embodiments, the present invention relates
to a liquid fuel tank that includes a housing have an inner chamber
capable of containing liquid fuel as well as an air space above an
upper surface of the liquid fuel. The liquid fuel tank further
includes a floating member included within the inner chamber, where
the floating member is configured to float proximate the upper
surface of the liquid fuel when the liquid fuel is present within
the inner chamber. Additionally, the floating member includes at
least one tapered surface, where the floating member covers a
majority of the upper surface of the liquid fuel, whereby the
liquid fuel evaporates to a lesser degree than would occur if the
floating member was absent.
[0007] Further, in at least some embodiments, the present invention
relates to a liquid tank. The liquid tank includes a portion of a
liquid capable of evaporation, and an interior region within which
the portion of the liquid is positioned, and further within which
is located an air space above an upper surface of the portion of
the liquid. The liquid tank also includes means for covering at
least a majority of the upper surface, where a covered part of the
upper surface is separated from the air space, whereby the
evaporation of the liquid occurs at a reduced level due to the
means for covering.
[0008] Additionally, in at least some embodiments, the present
invention relates to a method of operating a fuel tank. The method
includes filling the fuel tank with an amount of a liquid fuel,
where an air space remains above an upper surface of the liquid
fuel, and floating a structure within the fuel tank. The structure
floats proximate the upper surface of the liquid fuel and extends
upward out of the liquid fuel above the upper surface, the
structure includes a tapered surface such that a cross-sectional
area of the structure becomes increasingly smaller as one proceeds
upward along the structure away from the upper surface, and a
portion of the upper surface is separated from the air space due to
the structure.
[0009] Further, in at least some embodiments, the present invention
relates to a structure for implementation in a liquid fuel tank.
The structure includes at least one tapered surface, where the
structure is configured to float along an upper surface of liquid
fuel within the liquid fuel tank and reduce an exposed area of the
upper surface so as to reduce evaporation of the liquid fuel.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a side elevation view of a simplified fuel tank
that for convenience of illustration is shown to be transparent
where the fuel tank is semi-filled with fuel and employs a first
exemplary floating member in accordance with one embodiment of the
present invention;
[0011] FIG. 2 is a side elevation view of the fuel tank of FIG. 1,
wherein the fuel tank employs a second exemplary floating member in
accordance with another embodiment of the present invention;
and
[0012] FIG. 3 is a cross-sectional view of the fuel tank of FIG. 2,
taken along a line 3-3 of that figure
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0013] Referring to FIG. 1, a side elevation view of an exemplary
fuel tank 2, in accordance with at least some embodiments of the
present invention, is shown. For simplicity of illustration, the
fuel tank 2 is a container or housing formed from a transparent
material (e.g., a transparent plastic) so that the contents within
the fuel tank are visible through the wall of the fuel tank. It
will be understood, however, that in other embodiments the fuel
tank 2 can be made of a variety of materials, which need not be
transparent. Also for simplicity, the fuel tank 2 can be assumed to
have a cylindrical or substantially cylindrical shape, with a
central axis of the cylindrical fuel tank extending vertically or
substantially vertically. However, in alternate embodiments, the
fuel tank 2 can take on other shapes, including shapes that are
asymmetrical.
[0014] As shown, the fuel tank 2 is partially filled with fuel 6,
up to a level indicated by a surface 8. An air space 10 is formed
within the fuel tank 2 above the surface 8, within which
evaporative emissions from the fuel 6 ordinarily collect. As fuel
is drained from the fuel tank 2 by way of an output passage 4
(which can be assumed to be connected by way of a hose or other
channel to a carburetor, fuel injectors, etc.), the surface 8 moves
downward toward the bottom of the fuel tank and the air space 10
increases in volume. Fuel can be added to the fuel tank 2 by way of
an input orifice 5, which is sealed in the present embodiment by
way of a cap 15. The fuel 6 in the present embodiment is intended
to be representative of a wide variety of volatile fluids (e.g.,
fluids capable of evaporation at normal temperatures and pressures)
including, for example, gasoline, diesel fuel, kerosene, crude oil,
other petroleum-based fuels, mineral oils, ethanol blends etc. In
other embodiments, the fuel 6 can be an organic fluid such as
acetone and benzene or another type of volatile fluid other than
those mentioned above.
[0015] To minimize or possibly even completely eliminate
evaporative emissions, the fuel 6 has located thereon a floating
member 12. The floating member 12 is configured to stay afloat at
the surface 8 of the fuel 6. In the present embodiment, the
floating member 12 is made of a buoyant plastic although, in other
embodiments, it can be made of other non-metallic materials or
potentially of metallic materials as well. In the present
embodiment, the fuel tank 2 only includes the single floating
member 12, which is formed as a single piece, albeit in alternate
embodiments multiple floating members can be employed. It is
believed, however, that the use of a single floating member of
appropriate physical shape and size as discussed below is
advantageous relative to the use of multiple such members, both in
terms of providing robustness as well as limiting the overall
amount of evaporative emissions that occur.
[0016] Depending upon the embodiment, the floating member 12 can
have various shapes and sizes. Nevertheless, in the present
embodiment of FIG. 1, the floating member 12 is designed to be
conical (or substantially conical). FIG. 1 in particular shows the
floating member 12 to be conical in shape and to be tilted
slightly, such that a top 13 of the floating member is tipped away
from the viewer, and such that a base surface 17 of the floating
member is visible. It will be understood that, in practice, the
floating member 12, while generally tending to be upright in
position, will also rock and bob as the fuel 6 within the fuel tank
2 is jostled or otherwise moves about. Further as shown, the shape
of the base surface 17 is configured to generally correspond to the
inner perimeter of the fuel tank 2. Thus, in the present exemplary
embodiment of FIG. 1 in which the fuel tank 2 is cylindrical or
substantially cylindrical, the floating member 12 is a cone having
with the circular (or substantially circular) base surface 17 that
generally tracks the inner circular perimeter of the fuel tank.
[0017] The conical shape of the floating member 12 more
particularly is configured to achieve certain goals. First, the
floating member 12 is designed to maximize the extent to which,
when the floating member is floating within the fuel 6, the
floating member displaces and covers the fuel so as to reduce the
overall extent of the surface 8 of the fuel that is exposed to the
air space 10, thus reducing fuel evaporation. The presence of the
floating member 12 within the fuel tank 2 serves to reduce the
exposed surface area of the fuel 6 without changing the volume,
dimensions or any other characteristics of the fuel tank 2. As a
result of the floating member 12, the surface 8 of the fuel 6 in
the present embodiment is reduced to an annular region 9 around the
edge/perimeter of the floating member 12 existing between that
edge/perimeter and the inner surface of the fuel tank 2, and
evaporation of the fuel for the most part only occurs from that
annular region portion. In the present embodiment the floating
member 12 reduces the overall size of the exposed surface by at
least a half, or even more (e.g., by three-quarters, seven-eights
or even more), although any amount of reduction is possible
depending upon the embodiment.
[0018] Second, the configuration of the floating member 12 is
selected so as to limit or minimize the height of the floating
member, and/or so as to correspond to the shape of a roof or top
portion 19 of the fuel tank. This allows for the exposed area of
the surface 8 to remain minimized even while the fuel tank 2 is
completely filled with fuel 6. More particularly in the present
embodiment, the roof 19 of the fuel tank 2 is generally conic
(albeit with a slightly concave appearance) and thus corresponds
generally to the shape of the floating member 12. Consequently,
when fuel 6 is added to the fuel tank 12, the floating member 12
generally continues to rise upward along with the surface 8 until
the floating member encounters the roof 19 of the fuel tank, at
which point the fuel tank is completely filled. Assuming such a
design, there is generally no circumstance in which, due to a
limitation on movement of the floating member 12 upwards within the
fuel tank 2, the surface 8 rises relative to the floating member to
such an extent that evaporative emissions are significantly
increased.
[0019] In addition, the conical structure of the floating member 12
serves to minimize the condensation of evaporated fuel atop the
floating member. Rather, to the extent that fuel condenses atop the
conical floating member 12, it tends to flow off of the sides of
the cone back to the surface 8 of the fuel 6, where it reenters the
main store of fuel. Further, since in the present embodiment the
input orifice 5 of the fuel tank 2 is directly above the floating
member 12, fuel added to the fuel tank via the orifice likewise,
upon impacting the floating member, runs down the sides of the
floating member and enters the main store of fuel 6, without any
significant accumulation of fuel atop the floating member.
[0020] The conical floating member 12 can be made as a solid piece
or can be hollow as well. Further, the degree to which the floating
member 12 extends beneath the surface 8 of the fuel 6 can vary
depending upon the buoyancy of the floating member and the
particular fuel being used. Notwithstanding the fact that the
diameter of the conical floating member 12 is greater than its
height in the present embodiment, it is nevertheless intended in
other embodiments that the diameter be lesser than the height or
potentially be of an equal dimension as well.
[0021] Referring now to FIG. 2, an alternate embodiment of the
floating member, shown as a floating member 14, is shown to be
located within the fuel tank 2. In contrast to the floating member
12 of FIG. 1, the floating member 14 of FIG. 2 is a double-side
conical member including two cone sections, namely, an upper cone
section 16 and a lower cone section 18, which are attached
back-to-back at their respective bases at a junction 20 so as to
point in diametrically opposite (upward and downward) directions.
Such a double-sided conical floating member 14, in addition to
providing all the advantages of the floating member 12 of FIG. 1,
can also potentially avoid a situation where the conical floating
member flips over (e.g., 180 degrees) in such a manner as to limit
its effectiveness in reducing fuel evaporation and/or the amount of
fuel sitting atop the floating member. In particular, if the
floating member 14 of FIG. 2 flips end-over-end such that the upper
cone section 16 is inverted so as to point downward into the fuel
6, the lower cone section 18 consequently is inverted (from the
position shown) so as to point upward out of the fuel, and thus
both before and after the flipping event all of the advantages
provided by the floating member 12 continue to be provided.
[0022] Although the two conical sections 16 and 18 forming the
double-sided conical floating member 14 are shown to be of equal
height and diameter, the present invention is also intended to
encompass alternate embodiments of floating members having
different heights and diameters of the two cone sections. For
example, the cone section 18 can have a height that is larger than
its diameter while the cone section 16 has a height that is less
than its diameter, or vice-versa. It is, however, typically (albeit
not necessarily) the case that at least the diameters of the cone
sections 16 and 18 be of the same dimension to maximize the
advantages of the floating member 14 in minimizing evaporative
emissions. Also, while typically the conical floating member 14 is
designed as two cone sections 16 and 18 that are attached
back-to-back, both of which are made of the same material, in
alternate embodiments the two cones can be integrally formed as a
single piece or made of different materials. In addition, the
double-sided conical floating member 14 can be made as a solid or
hollow structure. As with respect to the floating member 12, the
height of the floating member 14 within the fuel 6 can vary
depending upon the buoyancy of the floating member, the
characteristics of the fuel, etc.
[0023] Turning now to FIG. 3, a cross-sectional view taken along a
line 3-3 of FIG. 2 is provided, showing the fuel tank 2 with the
conical floating member 14 partially immersed within the fuel 6. As
shown, the upper conical section 16 of the floating member 14 in
particular is visible, with a rim 22 of the junction 20 between the
conical sections 16, 18 of the floating member being visible
beneath the fuel surface 8 and an additional junction 24
illustrating where the surface of the fuel 6 meets the conical
section 16. A tip 26 of the floating member 14 typically remains
outside the surface of the fuel 6 at all times. An identical or
similar cross-sectional view would be provided assuming a similar
cut across the fuel tank of FIG. 1 employing the floating member
12. As is evident from FIG. 3, fuel is capable of evaporating only
from the annular region 9 between the additional Junction 24 and
the wall of the fuel tank 2.
[0024] Notwithstanding the above-described embodiments, the present
invention is intended to encompass a variety of other arrangements
of floating members and fuel tanks. For example, although the
present embodiments of FIGS. 1 and 2 do not illustrate the floating
members 12 and 14 as touching the sides of the fuel tank 2, the
present invention is nevertheless intended to include such
embodiments as well in which the floating member is in contact with
or in close proximity with the sides of the fuel tank 2. Further,
as already noted, the exact shapes and sizes of the floating
members and/or fuel tanks can vary with the embodiment. For
example, the fuel tank could have an oval cross-section (rather
than circular cross-section as shown in FIG. 3), or could be
box-like. The floating members can also take additional forms to
complement different fuel tank shapes and sizes. In at least some
embodiments, more than one floating member (e.g., two half-cones)
can be employed within a given fuel tank.
[0025] The present invention relates to a variety of embodiments of
fuel tanks and floating members as can be employed in a variety of
applications and for a variety of purposes. For example,
embodiments of the present invention can be employed in conjunction
with a variety of different internal combustion engines used in
vehicles or for a variety of other purposes. Embodiments of the
present invention can be particularly beneficial insofar as they
reduce or even eliminate evaporative emissions from the fuel.
[0026] Among other purposes, some embodiments of the present
invention can be employed in conjunction with SORE engines
including Class 1 and Class 2 small off-road engines such as those
implemented in various machinery and vehicles, including, for
example, lawn movers, snow mobiles and the like. Indeed, in at
least some such embodiments, the present invention is intended to
be applicable to "non-road engines" as defined in 40 C.F.R.
.sctn.90.3, which states in pertinent part as follows: "Non-road
engine means . . . any internal combustion engine: (i) in or on a
piece of equipment that is self-propelled or serves a dual purpose
by both propelling itself and performing another function (such as
garden tractors, off-highway mobile cranes, and bulldozers); or
(ii) in or on a piece of equipment that is intended to be propelled
while performing its function (such as lawnmowers and string
trimmers); or (iii) that, by itself or in or on a piece of
equipment, is portable or transportable, meaning designed to be and
capable of being carried or moved from one location to another.
Indicia of transportability include, but are not limited to,
wheels, skids, carrying handles, dolly, trailer, or platform."
[0027] Also, in at least some additional embodiments, embodiments
of the present invention are applicable to engines that have less
than one liter in displacement, or engines that both have less than
one liter in displacement and fit within the guidelines specified
by the above-mentioned regulations. In still further embodiments,
the present invention is intended to encompass other small engines,
large spark ignition (LSI) engines, and/or other larger (mid-size
or even large) engines. In additional embodiments, the present
invention is intended to be used with containers or storage tanks
other than fuel tanks holding volatile fluids, which are producers
of volatile organic compounds (VOC) or evaporative emissions.
[0028] It is specifically intended that the present invention not
be limited to the embodiments and illustrations contained herein,
but include modified forms of those embodiments including portions
of the embodiments and combinations of elements of different
embodiments as come within the scope of the following claims.
* * * * *