Note: Descriptions are shown in the official language in which they were submitted.
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"FUEL TANK BAFFLE FOR VEHICLE"
FIELD OF THE INVENTION
[001] The invention relates to vehicle fuel tanks, and more specifically, to a
reservoir baffle
arrangement for a vehicle fuel tank that allows use of more of the fuel tank
volume. The
invention has advantageous use in cylindrical fuel tanks as are used in heavy
duty trucks.
BACKGROUND AND SUMMARY
[002] Diesel powered trucks use externally mounted fuel tanks that are
typically cylindrical in
shape and mounted longitudinally on the truck frame. Because of the placement
and length of
the fuel filler neck, an upper portion of the tank volume is lost. In
addition, depending on
mounting of the draw tube, the orientation of the tube and the location of the
tube mouth, a
residual amount of fuel must remain in the tank to cover the draw tube mouth,
so that the fuel
pump can deliver fuel under all conditions. The residual amount of fuel in the
bottom of the tank
must accommodate tilting of the tank when the vehicle climbs or descends a
grade.
[003] Thus, the useful volume of the fuel tank is less than the total volume
defined by the walls
of the tank.
[004] A disadvantage is that for a given fuel tank the range -of the vehicle
is less than it would
be if more of the residual fuel volume could be used. From another point of
view, the fuel tank
may be considered to be larger than would be necessary if more of the residual
volume could be
used. Another disadvantage is that the vehicle weight may unnecessarily
include the weight of
the residual fuel volume and the added weight of the larger fuel tank.
[005] The invention provides a device that allows the vehicle to use more of
the residual fuel
than a conventional fuel tank. Accordingly, a small fuel tank-may be used
which can save space
on the frame, and the vehicle weight can be reduced.
[006] A device according to the invention includes a first wall portion having
an inner end and
an outer end and'formed as a spiral of about 270 degrees turning in a first
directiorn and a second
wall portion having an inner end and an outer end and formed as a spiral of
about 270 degrees
turning in a second direction opposite the first direction. The first wall
portion and second wall
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portion are positioned with the respective inner ends in opposed spaced
relation to define a
central -reservoir, and the respective outer ends are spaced from the other
wall portion to form
inlets on opposite sides, the portions between the inner ends and outer ends
defining
passageways to the central reservoir.
[007] According to another aspect of the invention, a plane defining an
interface between the
inner end of the first wall portion and the inner end of the second wall
portion is perpendicular to
planes defining the inlets.
[008] According to yet another aspect of the invention, a distance between the
first wall portion
and the second wall portion is greatest where the respective outer ends form
the inlets and
narrows as the passageways lead to the central reservoir.
[oo9] According to the invention, the first wall portion and second wall
portion are formed of
sheet material and are perpendicular to a bottom of the baffle arrangement.
[010] The invention also contemplates a fuel tank arrangement for a vehicle,
including, a tank
having a cylindrical outer wall defining an interior having an axial
direction. A baffle
arrangement is mounted in a bottom of the tank, the baffle arrangement having
a first wall
portion having an inner end and an outer end and formed as a spiral of about
270 degrees turning
in a first direction, a second wall portion having an inner end and an outer
end and formed as a
spiral of about 270 degrees turning in a second direction opposite the first
direction, the first wall
portion and second wall portion positioned with the respective inner ends in
opposed spaced
relation to define a central reservoir, and with the respective outer ends
spaced from the other
wall portion to form inlets on opposite sides, the portions between the inner
ends and outer ends
defining passageways to the central reservoir, the baffle arrangement being is
oriented so that the
inlets open in the axial direction, and, a draw tube mounted to extend with a
mouth in the central
reservoir.
BRIEF DESCRIPTION OF THE DRAWINGS
[O11] The invention will be better understood with reference to the appended
drawings, in
which:
[012] Figure 1 is a perspective view of an embodiment of a baffle arrangement
in accordance
with the invention;
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[013] Figure 2 is a top view of the embodiment of Figure 1; and,
[014) Figure 3 is an end view of a fuel tank showing schematically the
orientation of a fuel
draw tube with a baffle arrangement.
DETAILED DESCRIPTION OF THE INVENTION
[015] Figure I shows a perspective view of a baffle arrangement 5 for a fuel
tank in accordance
with the invention and Figure 2 is a top view of the baffle arrangement of
Figure 1. The
arrangement 5 includes a first wall 10 and a second wal120 that are positioned
vertically with
respect to a floor or bottom 30. The first wall 10 is formed as a spiral of
about 270 turning in a
first direction from an outer edge 12 to an inner edge 14. The second wall 20
is formed also
formed as a spiral of about 270 , but turning in a second direction opposite
the first direction
from an outer edge 22 to an inner edge 24.
[016] The first wall 10 and second wa1120 are positioned in a nested
arrangement with the
respective inner ends 14, 24 in opposed spaced relation to define a central
reservoir 40. The
respective outer ends 12, 22 are spaced from the other wall portion to form
inlets 50, 52 on
opposite sides of the baffle arrangement 5. The respective walls 10, 20
between the inner ends
and outer ends define passageways from the inlets 50, 52 to the central
reservoir 40.
[017] As shown in Figure 3, the baffle arrangement 5 provides a reservoir at a
bottom of a fuel
tank 60, represented here as an end section of a cylindrical tank. A draw tube
62 is positioned
with an inlet or mouth 64 disposed in the central reservoir 40 to draw fuel
from the tank.
[018] As will be recognized, the floor 30 of the baffle arrangement 5 will be
formed with a
curvature to fit without a gap on the bottom of the tank 60. Alternatively,
the first wall 10 and
second wall 20 may be mounted directly to the wall of the fuel tank 60.
[o19] The baffle arrangement 50 is mounted in a fuel tank (for example, the
fuel tank 60) so
that the inlets 50, 52 are open in the longitudinal or axial direction of the
tank, which normally
coincides with the front to back direction of the vehicle on which the tank is
rriounted. The
broken line A in Figure 2 indicates the longitudinal direction for mounting
purposes.
[020] As will be understood by those skilled in the art, the baffle
arrangement of the invention
may be used in a cylindrical tank as shown, or.in tanks of other shapes, for
example, D-shaped,
rectangular, oval and the rest. The baffle arrangement will function optimally
in a tank shaped
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so,that fuel collects in or near the place the baffle is installed, for
example, a tank that has a
longitudinal dimension greater than a lateral dimension. The dimensions of the
baffle itself,
particularly the lateral dimensions, may be selected to optimize the
collection of fuel, as will be
understood. .
[021] As a vehicle moves, climbing or descending grades, accelerating or
braking, turning left
or right, fuel will move in the tank. If the fuel level is low, the baffle
arrangement 5 will ensure
that the mouth 64 of the draw tube 62 is covered so that fuel and not air is
drawn into the fuel
system. The curvature of the first wall 10 and second wall 20 and their
respective positions form
traps for moving fuel.
[022] For example, when fuel may move forward and back, that is, along the
axis A because of
the vehicle is on a grade or is experiencing acceleration forces, one of the
walls 10, 20 will act as
a cup to trap fuel. The cup may be understood to be the portion between the
outer edge 22 and
inner edge 24, using the second wall 20 as an example. The first wall 10
between the outer edge
12 and inner edge 14 acts as a cup for fuel moving in the opposite direction.
[023] It will be understood that fuel will fill the cup formed by a wall until
the volume of fuel
spills over the respective inner edge 14, 24 and out through the opposing
passage. The working
volume of the baffle arrangement 5 may be adjusted by changing the height of
the walls 10, 12,
the curvature of the spiral, and the relatively spacing between the walls.
[024] For lateral movements of fuel in the tank, for example, during a tu.m,
the portion of the
wall 10 to the left of the axis A in Figure 2, that is, between the inner edge
14 and where the axis
A intersects the first wall 10 acts as trap fuel from flowing out of the
reservoir 40.
Correspondingly, the second wal120 forms a trap for lateral fuel movements of
the opposite
direction between the inner edge 24 and the point where the axis A intersects
the second wall 20.
[025] The first wall 10 and second wall 20 are formed as smooth curves to
facilitate the flow of
fuel through and for simplicity in manufacturing. Alternatively, a baffle
arrangement 105 may
include walls 110, 120 formed as straight segments joined at corners as shown
in Figure 4. Note
that the inner segment 114, 124 of each wall 110, 120 is generally
perpendicular to the outer
segment 112, 122 of the respective wall so that the same fuel trap arrangement
is provided.
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[026] The invention has been described in terms of preferred embodiments, but
those of skill in
the art will understand that equivalents may be substituted without departing
froin the scope of
the invention as defined in the appended claims.
