US20110000921A1 - Reservoir Baffle Arrangement for a Vehicle Fuel Tank - Google Patents

Abstract

A baffle arrangement for a vehicle fuel tank includes first and second wall portions, each having an inner end and an outer end and formed as a spiral of about 270 degrees. The first wall portion and second wall portion are 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.

Description

FIELD OF THE INVENTION
• 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
• 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.
• Thus, the useful volume of the fuel tank is less than the total volume defined by the walls of the tank.
• 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.
• 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.
• 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 direction 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 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.
• 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.
• 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.
• 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.
• 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
• The invention will be better understood with reference to the appended drawings, in which:
• FIG. 1 is a perspective view of an embodiment of a baffle arrangement in accordance with the invention;
• FIG. 2 is a top view of the embodiment ofFIG. 1; and,
• FIG. 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
• FIG. 1 shows a perspective view of abaffle arrangement5 for a fuel tank in accordance with the invention andFIG. 2 is a top view of the baffle arrangement ofFIG. 1. Thearrangement5 includes afirst wall10 and asecond wall20 that are positioned vertically with respect to a floor orbottom30. Thefirst wall10 is formed as a spiral of about 270° turning in a first direction from anouter edge12 to aninner edge14. Thesecond wall20 is formed also formed as a spiral of about 270°, but turning in a second direction opposite the first direction from anouter edge22 to aninner edge24.
• Thefirst wall10 andsecond wall20 are positioned in a nested arrangement with the respectiveinner ends14,24 in opposed spaced relation to define acentral reservoir40. The respectiveouter ends12,22 are spaced from the other wall portion to forminlets50,52 on opposite sides of thebaffle arrangement5. Therespective walls10,20 between the inner ends and outer ends define passageways from theinlets50,52 to thecentral reservoir40.
• As shown inFIG. 3, thebaffle arrangement5 provides a reservoir at a bottom of afuel tank60, represented here as an end section of a cylindrical tank. Adraw tube62 is positioned with an inlet ormouth64 disposed in thecentral reservoir40 to draw fuel from the tank.
• As will be recognized, thefloor30 of thebaffle arrangement5 will be formed with a curvature to fit without a gap on the bottom of thetank60. Alternatively, thefirst wall10 andsecond wall20 may be mounted directly to the wall of thefuel tank60.
• Thebaffle arrangement50 is mounted in a fuel tank (for example, the fuel tank60) so that theinlets50,52 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 mounted. The broken line A inFIG. 2 indicates the longitudinal direction for mounting purposes.
• 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 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.
• 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, thebaffle arrangement5 will ensure that themouth64 of thedraw tube62 is covered so that fuel and not air is drawn into the fuel system. The curvature of thefirst wall10 andsecond wall20 and their respective positions form traps for moving fuel.
• 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 thewalls10,20 will act as a cup to trap fuel. The cup may be understood to be the portion between theouter edge22 andinner edge24, using thesecond wall20 as an example. Thefirst wall10 between theouter edge12 andinner edge14 acts as a cup for fuel moving in the opposite direction.
• It will be understood that fuel will fill the cup formed by a wall until the volume of fuel spills over the respectiveinner edge14,24 and out through the opposing passage. The working volume of thebaffle arrangement5 may be adjusted by changing the height of thewalls10,12, the curvature of the spiral, and the relatively spacing between the walls.
• For lateral movements of fuel in the tank, for example, during a turn, the portion of thewall10 to the left of the axis A inFIG. 2, that is, between theinner edge14 and where the axis A intersects thefirst wall10 acts as trap fuel from flowing out of thereservoir40. Correspondingly, thesecond wall20 forms a trap for lateral fuel movements of the opposite direction between theinner edge24 and the point where the axis A intersects thesecond wall20.
• Thefirst wall10 andsecond wall20 are formed as smooth curves to facilitate the flow of fuel through and for simplicity in manufacturing. Alternatively, abaffle arrangement105 may includewalls110,120 formed as straight segments joined at corners as shown inFIG. 4. Note that theinner segment114,124 of eachwall110,120 is generally perpendicular to theouter segment112,122 of the respective wall so that the same fuel trap arrangement is provided.
• 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 from the scope of the invention as defined in the appended claims.

Claims (8)

1. A baffle arrangement for a vehicle fuel tank, comprising:

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.

2. The baffle arrangement as claimed inclaim 1, wherein 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.

3. The baffle arrangement as claimed inclaim 1, wherein a width of the inlets is greater than a distance between the respective inner ends of the first wall portion and second wall portion.

4. The baffle arrangement as claimed inclaim 1, wherein the first wall portion and second wall portion are formed of sheet material and are perpendicular to a bottom of the baffle arrangement.

5. The baffle arrangement as claimed inclaim 1, wherein 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.

6. The baffle arrangement as claimed inclaim 1, wherein each wall portion is formed as a smooth curve.

7. The baffle arrangement as claimed inclaim 1, wherein each wall portion is formed as a series of straight wall segments.

8. A fuel tank arrangement for a vehicle, comprising:

a tank having an outer wall defining an interior having an axial direction;

a baffle arrangement mounted in a bottom of the tank and 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;

wherein, the baffle arrangement 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.

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