Information
-
Patent Grant
-
6270310
-
Patent Number
6,270,310
-
Date Filed
Wednesday, September 29, 199924 years ago
-
Date Issued
Tuesday, August 7, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Lopez; F. Daniel
- Nguyen; Ninh
Agents
-
CPC
-
US Classifications
Field of Search
US
- 415 551
- 415 228
- 415 2141
- 415 227
- 416 189
- 416 231 R
-
International Classifications
-
Abstract
A fuel pump assembly 10 including a motor 12, a drive shaft 14 which is rotatably coupled to motor 12, an impeller 16, and a chamber assembly 18. Fuel pump assembly 10 has improved efficiency due to the substantial reduction and/or elimination of frictional contact between impeller 16 and the respective interior surfaces 70, 72 of chamber 18.
Description
FIELD OF THE INVENTION
This invention relates to a fuel pump assembly and more particularly to a vehicle fuel pump assembly having an improved operating efficiency.
BACKGROUND OF THE INVENTION
Fuel pump assemblies are typically used to selectively pump and/or transfer fuel from a fuel-containing tank or storage receptacle to an engine, thereby allowing the fuel to be combusted within the engine and causing the engine to perform some desired function or operation.
A fuel pump assembly is typically located within a vehicle fuel tank and normally includes an electric motor, an impeller, and a shaft which connects the electric motor to the impeller. The impeller is usually and movably housed and/or contained within a pump chamber or cavity which is formed by the cooperative engagement of a chamber cover member and a chamber body member, and which is communicatively coupled to the vehicle engine.
In operation, the electric motor selectively rotates and/or “drives” the shaft, thereby rotating the impeller. The rotating impeller “draws” and/or pumps fuel, such as gasoline or ethanol, from the fuel tank, through the fuel pump chamber, and into the vehicle engine. It is desirable to provide relatively large amounts of the fuel at a relatively high rate and/or speed in order to allow the vehicle to be selectively driven at relatively high and desirable speeds. It is further desirable to allow the fuel pump assembly to operate efficiently (e.g., without substantial losses of energy).
The rate and the speed at which the fuel is pumped into the vehicle engine can be and has been desirably increased by increasing the diameter of the impeller and increasing the size of the impeller containing pump chamber. While these modified fuel pumps have reliably pumped increased amounts of fuel at increased rates or speeds, they suffer from some undesirable drawbacks.
For example and without limitation, the pressure differential, which is created within the pump chamber by the rotating impeller, causes the impeller to undesirably contact the interior chamber forming surfaces, thereby creating significant frictional energy losses. These frictional losses decrease the overall speed of the impeller and decrease the overall efficiency of the fuel pump. Importantly, the amount of these frictional energy losses increase as the size or the diameter of the impeller is increased due the concomitant increase in the amount of the impeller surface area which operatively and frictionally contacts the interior surfaces of the chamber. Hence, increasing the size and/or the diameter of the impeller actually increases the amount of such undesirable frictional energy losses. Furthermore, the relatively large impeller tends to operatively “warp” or deform, thereby further increasing the amount of frictional contact between the impeller and the interior surfaces of the chamber and further undesirably increasing such frictional energy losses.
These prior vehicle fuel pump assemblies suffer additional energy losses due to the fluid displacement occurring at the tips or the ends of the impeller blades. In order to minimize these known “blade tip losses”, the chamber body and/or cover is usually created or “machined” within very strict or “tight” tolerance limits in order to minimize the distance between the blade tips and the interior surfaces of the pump chamber. This requirement undesirably increases the manufacturing and/or production cost of these prior fuel pump assemblies and the relatively short distance between the impeller blades and the interior surfaces of the pump chamber undesirably increases the likelihood of frictional contact between the blades and the interior chamber surfaces.
There is therefore a need for an improved fuel pump assembly for use in a vehicle, which substantially reduces and/or eliminates such previously described frictional contact and “blade tip” type energy losses, and which reliably provides relatively large amounts of fuel to the vehicle engine at relatively high rates of speed.
SUMMARY OF THE INVENTION
It is a first object of the invention to provide a vehicle fuel pump assembly which overcomes some or all of the previously delineated drawbacks of prior vehicle fuel pumps.
It is a second object of the invention to provide a vehicle fuel pump assembly which includes a chamber cavity having a selectively rotating impeller, the fuel pump being adapted to substantially reduce and/or eliminate contact between the rotating impeller and the chamber forming surfaces.
It is a third object of the present invention to provide a vehicle fuel pump assembly which substantially reduces and/or minimizes blade tip energy losses.
According to a first aspect of the present invention, a fuel pump assembly for use with a vehicle of the type having a fuel tank which contains a quantity of fuel and a combustion engine is provided. The fuel pump assembly includes a motor having a selectively rotating shaft; a chamber which receives the shaft and which is communicatively coupled to the fuel tank and to the combustion engine; and an impeller which is coupled to the shaft, which is movably disposed within the chamber, and which has a first body portion and several blade portions which project from the first body portion and which are each respectively thinner than the first body portion.
According to a second aspect of the present invention, a method is provided for increasing the efficiency of a fuel pump of the type having a selectively rotating impeller including several projecting blades of a certain respective of thickness. The method includes the steps of reducing the certain thickness of each of the several blades; and interconnecting the several blades, thereby increasing the efficiency of the fuel pump.
These and other objects, aspects, features, and advantages of the present invention will become apparent from a consideration of the following specification and the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a front and partial cut-away view of a fuel pump assembly which is made in accordance with the teachings of the preferred embodiment of the invention;
FIG. 2
is an unassembled perspective view of the impeller which is employed within the fuel pump assembly shown in
FIG. 1
;
FIG. 3
is an unassembled perspective view of the pump chamber body member which is employed within the fuel pump assembly shown in
FIG. 1
;
FIG. 4
is an unassembled perspective view of the pump chamber cover which is employed within the fuel pump assembly shown in
FIG. 1
;
FIG. 5
is a cross sectional view of the impeller shown in
FIGS. 1 and 2
;
FIG. 6
is a cross sectional view of a pump chamber formed by the selectively and operative engagement of the pump chamber body shown in FIG.
3
and the pump chamber cover shown in
FIG. 4
;
FIG. 7
is a perspective unassembled view of a pump chamber body member which is made in accordance with the teachings of a second embodiment of the invention and which is adapted for use with fuel pump which is shown in
FIG. 1
;
FIG. 8
is a perspective unassembled view of a pump chamber cover member which is made in accordance with the teachings of a second embodiment of the invention and which is adapted for use with the fuel pump shown in
FIG. 1
; and
FIG. 9
is a cross sectional view of a fuel pump chamber member which is formed by the selective and operative engagement of the pump chamber body member which is shown in FIG.
7
and the pump chamber cover member which is shown in FIG.
8
.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to
FIGS. 1-6
, there is shown a vehicle fuel pump assembly
10
which is made in accordance with the teachings of the preferred embodiment of the invention. As shown, fuel pump assembly
10
includes a motor
12
, a drive shaft
14
which is rotatably and operatively coupled to the motor
12
, and a chamber assembly
18
which rotatably receives the driveshaft
14
. Motor
12
, driveshaft
14
, and chamber assembly
18
are collectively contained within a generally cylindrical housing
20
.
Chamber assembly
18
includes a chamber cover member
24
having an integrally formed fuel intake passage or port
26
, a chamber body member
22
having a fuel outlet aperture or port
28
and operatively cooperating with cover member
22
to form a chamber cavity
30
, and an impeller
16
which is coupled to shaft
14
and which is rotatably disposed within cavity
30
. Assembly
10
further includes a pump outlet member or port
32
which is communicatively coupled to aperture or port
28
.
As described more fully and completely below, the selective rotation of impeller
16
causes fuel to be selectively received by the assembly
18
through port
26
. The received fuel is then pumped and/or propelled through cavity
30
and through aperture
28
, before exiting assembly
10
from port
32
. As should be realized by those of ordinary skill in the art, port or aperture
32
is selectively and communicatively coupled to a conventional vehicle combustion engine (not shown), thereby allowing the fuel to be received and selectively combusted within the engine.
In the preferred embodiment of the invention, motor
12
comprises a conventional and commercially available electric “DC”-type motor (e.g., a motor which is powered through direct current electricity), and is adapted to selectively and rotatably drive shaft
14
. Particularly, shaft
14
extends from motor
12
into chamber assembly
18
through an aperture
34
which is formed within body member
22
. As shown, aperture
34
contains a conventional and commercially available “set” or pair of bearings
36
which rotatably engage shaft
14
and allow shaft
14
to rotate freely within aperture
34
. These bearings
36
cause shaft
14
to rotate about an axis of rotation
94
which, in one non-limiting embodiment of the invention, is made to maintain a position which substantially overlays and/or corresponds to the longitudinal axis of symmetry of aperture
34
. Shaft
14
further extends through cavity
30
and into the slot
37
which is formed within cover member
24
. The rounded end
38
of shaft
14
rotatably rests upon a conventional “thrust button” or member
40
which is secured within slot
37
.
As best shown in
FIGS. 2 and 5
, impeller
16
is generally circular in shape and includes a generally circular and relatively thin inner body or core portion
42
; a generally circular and relatively thick or “landed” outer body or core portion
44
; several relatively thin and curved vanes or blades
46
which are circumferentially disposed upon and which project and/or protrude from portion
44
; several flange portions or “vane groove”
48
which project from portion
44
and which are each operatively and abuttingly positioned between a unique pair of blades
46
; and an outer ring portion
50
which is connected to blade tips
47
, thereby interconnecting blades
46
. Portions
42
,
44
, blades
46
, flange portion or “vane groove”
48
and ring
50
are, in one non-limiting embodiment of the invention, integrally formed from a durable corrosion-resistant material, such as a phenolic or “PPS” type plastic. In the preferred embodiment, impeller
16
is molded by use of a conventional thermal molding process and may include conventional filler materials such as glass, resin and/or graphite.
Core portion
42
includes a centrally disposed aperture
52
which matingly and frictionally receives shaft
14
. Hence, the shaft
14
is operatively coupled to the impeller
16
, thereby causing the impeller
16
to rotate and to “freely” slide or travel upon shaft
14
and within chamber cavity
30
in the directions illustrated by arrows
56
,
57
(e.g., along axis
94
), shown in FIG.
1
. Core portions
42
and
44
further each include several substantially identical and distributably disposed pressure relief apertures
58
. Particularly, apertures
58
allow fuel to pass between opposed side surfaces of impeller
16
, thereby substantially equalizing the pressure within cavity
30
, substantially reducing the amount of force imparted upon impeller
16
in the directions illustrated by arrows
56
,
57
and reducing the amount of frictional contact between impeller
16
and the body
22
and/or cover
24
.
To further substantially prevent and/or reduce frictional contact between the impeller
16
and body member
22
and between the impeller
16
and the cover member
24
, the “thickness” or the width
59
of the blades
46
and the ring portion
50
and the “thickness” or the width
60
of portion
42
are each made to be respectively uniform and relatively less than the relatively uniform width or “thickness”
62
of portion
44
. As discussed more fully and completely below, the narrowing and/or thinning of blades
46
, ring
50
, and portion
42
ensures that blades
46
, ring
50
, and portion
42
will not contact the cover member
24
and/or the body member
22
during operation, thereby minimizing the contact between impeller
16
and the respective interior surfaces
70
,
72
which form and/or create the pump chamber
30
and allowing the fuel pump assembly
10
to become more efficient.
In one non-limiting embodiment of the present invention, the thickness
59
is approximately 4.65 millimeters, the thickness
60
is approximately 4.65 millimeters, the thickness
62
is approximately 4.75 millimeters, and the overall diameter
68
of impeller
16
is approximately 54 millimeters.
Body member
22
and cover member
24
are best illustrated in
FIGS. 3
,
4
and
6
. As shown, body member
22
and cover member
24
are preferably manufactured from a relatively durable and substantially corrosive-resistant material, such as a plastic material, anodized aluminum, or any other suitable material or composite. Further, body member
22
and cover member
24
each respectively includes an outer ridge or lip portion
74
,
76
which selectively and cooperatively engage or interlock, as illustrated in
FIGS. 1 and 6
, thereby selectively creating a substantially sealed cavity
30
. Body member
22
and cover member
24
each further respectively include an integrally formed semi-circular groove
73
,
75
. When body member
22
and cover member
24
are operatively interconnected, grooves
73
,
75
cooperatively form a fuel passage channel
77
which directs the flow of the received fuel within the cavity
30
and, more particularly, provides a path of fuel travel from the inlet
26
to the outlet
28
.
Further, body member
22
and cover member
24
respectively include tapered surface portions
78
,
80
. In one non-limiting embodiment, portions
78
,
80
are each “tapered” or sloped at a substantially identical rate or angle
82
, which in one non-limiting embodiment is approximately equal to 0.36 degrees. Further, in one non-limiting embodiment, portions
78
,
80
each have a respective and substantially identical uniform width
84
,
86
of approximately 8 millimeters. Portions
78
,
80
cooperatively widen the portion of the chamber
30
in which the relatively thick portion
44
of impeller
16
operatively resides, thereby allowing impeller
16
to move in the direction of arrows
56
,
57
without immediately engaging the interior chamber forming surfaces
70
,
72
, thereby further increasing the overall efficiency of the fuel pump assembly
10
. In one non-limiting embodiment, distances
88
,
90
which respectively correspond to the maximum distance by which each portion
78
,
80
“widens” chamber
30
is approximately 0.05 millimeters.
The overall diameter
92
of cavity
30
formed by the selective engagement of body member
22
and cover member
24
is greater than the overall impeller diameter
68
to ensure sufficient clearance between blade tips and the chamber forming surface. In one non-limiting embodiment, the overall diameter
92
of cavity
30
is approximately 54.2 millimeters. As discussed below, ring portion
50
allows diameter
92
to be relatively and considerably greater than impeller diameter
68
. Particularly, ring portion
50
substantially eliminates/reduces blade tip losses, thereby allowing for a “looser” tolerance between diameter
92
and diameter
68
, thereby obviating the need to precisely machine body
22
and/or cover
24
. Furthermore, the “tapering” or “sloping” of body member
22
and cover member
24
further reduces the amount of frictional contact between impeller
16
and the interior pump chamber forming surfaces
70
,
72
.
In operation, the selective rotation of shaft
14
by motor
12
causes impeller
16
to rotate within cavity
30
about the axis of rotation
94
of shaft
14
. The rotation of impeller
16
selectively draws fuel through inlet
26
and pumps and/or propels the received fuel through cavity
30
and aperture
28
, and out of assembly
10
through port
32
. The rotation of impeller
16
causes and/or creates forces which act in the directions of arrows
56
,
57
. Particularly, these forces cause impeller
16
to slide upward and/or downward upon shaft
14
. Unlike prior pump assemblies, these forces do not cause substantial frictional contact between the operatively rotating impeller
16
and the pump chamber forming surfaces
70
,
72
.
If impeller
16
is forced “upward” (i.e., in the direction of arrow
56
) only the top surface
64
of portion
44
will contact the interior surface
70
of body member
22
, thereby allowing the relatively thin blades
46
and the ring portion
50
to rotate freely below surface
70
. Should the impeller
16
be forced “downward” (i.e., in the direction of arrow
57
), only the bottom surface
66
of portion
44
will contact the pump chamber forming interior surface
72
of cover member
24
, thereby allowing the relatively thin blades
46
and the ring portion
50
to rotate freely above surface
72
.
The “tapering” or “sloping” of portions
78
,
80
(e.g., the selective “widening” of cavity
30
) combined with the relatively thin inner core portion
42
further minimize the contact between impeller
16
and the respective interior surfaces
70
,
72
, in a substantially similar manner. That is, this “tapering” substantially permits contact to occur between only the portion
44
and the portion of surfaces
70
,
72
nearest to and/or proximate to respective channels
73
,
75
, while substantially preventing contact between portion
42
and surfaces
70
,
72
. In this manner, frictional contact between the impeller
16
and body
22
and/or cover member
24
is minimized, thereby providing relatively greater impeller speeds, an increased pumping rate, and improved overall pump efficiency.
The efficiency of pump assembly
10
is further increased due to ring
50
. Particularly, ring portion
50
allows diameter
92
to be significantly greater than impeller diameter
68
, thereby allowing for a “looser” tolerance. This “looser” tolerance provides a greater distance between the outer circumference of impeller
68
and the circumference of cavity
30
, thereby decreasing the amount and likelihood of contact occurring between blades
46
and body
22
and/or cover
24
. This “looser” tolerance is achieved without “blade” tip losses, as ring
50
encompasses and/or interconnects the tips
47
of blades
46
, thereby preventing or substantially reducing undesirable blade tip fluid displacement during the rotation of impeller
16
.
It should be understood that the thin portion
42
of impeller
16
, the tapered body member
22
and cover member
24
, the thin blades
46
, and/or the ring portion
50
may each be used independently to unilaterally reduce the amount of frictional contact within a fuel pump assembly as previously described. These aspects/features may also be desirably combined with a single fuel pump assembly.
Referring now to
FIGS. 7
,
8
, and
9
, there is respectively shown a chamber body member
122
, a chamber cover member
124
, and a chamber assembly made in accordance with the teachings of a second embodiment of the present invention. Except as otherwise delineated below, body member
122
and cover member
124
are substantially identical in structure and function to body member
22
and cover member
24
. Particularly, members
122
and
124
may selectively and operatively replace members
22
and
24
in the fuel pump assembly
10
which has been previously described. Moreover, with the exception of portions
178
,
180
, body member
122
and cover member
124
each respectively include substantially identical elements/portions/characteristics as body member
22
and cover member
24
. Elements having a substantially identical structure and function are defined by the same reference numerals as body member
22
and cover member
24
, delineated in
FIGS. 3
,
4
and
6
, with the exception that elements of body member
122
and cover member
124
have their respective reference numerals incremented by
100
.
Unlike portions
78
,
80
, portions
178
,
180
of body member
122
and cover member
124
are not “tapered” or “sloped”. Rather, portions
178
,
180
each respectively have a generally circular and relatively narrow outer “landed” or raised portions
179
,
181
which are contiguous to and integrally formed with generally circular inner recessed portions
183
,
185
. Portions
179
,
181
are respectively contiguous to channels
173
,
175
and have respective substantially identical and substantially flat opposed surfaces
195
,
197
.
Portions
179
,
181
have respective widths
187
,
189
which are relatively less than the respective widths
191
,
193
of portions
183
,
185
. In one non-limiting embodiment, widths
187
,
189
are each equal to approximately 2.0 millimeters and widths
191
,
193
are each equal to approximately 6.0 millimeters. In one non-limiting embodiment, the amount or distance
199
,
201
that portions
179
,
181
respectively extend from recessed portions
183
,
185
are substantially identical and, in one non-limiting embodiment, distances
199
,
201
are each equal to approximately 0.05 millimeters.
Cover member
122
and body member
124
cooperate with impeller
16
to substantially ensure that minimal frictional contact results from the movement of impeller
16
. Particularly, if impeller
16
is forced against body
122
, the only contact which will occur is between portion
44
of impeller
16
and the relatively thin surface
195
of portion
179
. Likewise, if impeller
16
is forced against cover
124
, the only contact which will occur is between portion
44
of impeller
16
and the relatively thin surface
197
of portion
181
. In this manner, frictional contact between the impeller
16
and body
122
and/or cover
124
is substantially reduced, thereby providing relatively greater impeller speeds, an increased pumping rate, and improved efficiency. Moreover, this “stepped” design allows body
122
and cover
124
to be more easily molded and requires less machining than the “tapered” or sloped design of body
22
and cover
24
.
It is understood that the invention is not limited by the exact construction or method illustrated and described above but that various changes and/or modifications may be made without departing from the spirit and/or the scope of Applicants' inventions.
Claims
- 1. A fuel pump assembly comprising:a motor having a selectively rotating shaft; a chamber which receives said shaft ; and an impeller which is coupled to said shaft and which is movably disposed within said chamber, and which has a body portion having a thin inner portion and a thick outer portion and several blade portions which are integrally formed with and project from said thick outer body portion and which are each respectively thinner than said body portion.
- 2. The fuel pump assembly of claim 1 wherein said impeller further includes a ring portion which is connected to said several blade portions.
- 3. The fuel pump assembly of claim 2 wherein each of said several blade portions has a tip and wherein said ring portion is connected to each of said tips of said blade portions.
- 4. The fuel pump assembly of claim 1 wherein said body portion includes a plurality of apertures.
- 5. The fuel pump assembly of claim 1 wherein said inner portion of said body is deployed within a first portion of the chamber and wherein said outer portion of said body is deployed within a second portion of said chamber, said first and second portions of said chamber having a respective height and wherein said height of said first portion of said chamber is less than said height of said second portion of said chamber.
- 6. The fuel pump assembly of claim 1 further comprising a first member and a second member which cooperatively form said chamber.
- 7. The fuel pump assembly of claim 6 wherein said first and second members include grooves which cooperatively form a fuel path within said chamber.
- 8. A fuel pump assembly comprising:a housing; a motor disposed within said housing; a shaft which is coupled to said motor and which is rotated by said motor; a pump chamber body member having an aperture through which said shaft extends and further having a first surface in which a first channel is formed, said surface further including a first raised portion and a second portion; a pump chamber cover member having a second surface in which a second channel is formed, and cooperating with said pump chamber body member to form a pump chamber; and an impeller which is coupled to said shaft, disposed within said pump chamber, and being rotated within said pump chamber by said motor, said impeller having a certain shape which cooperates with said first raised portion to substantially prevent contact between said impeller and said second portion as said impeller rotates within said chamber, said impeller further having a generally circular core portion and a plurality of blades projecting from said core portion, said core portion being thicker than each of said plurality of blades.
- 9. The fuel pump assembly of claim 8 wherein said cover member further includes a slotted portion, a second raised portion, and a third portion which is formed between said second channel and said slotted portion.
- 10. The fuel pump assembly of claim 8 wherein said cover member further comprises a thrust button which engages said shaft.
- 11. The fuel pump assembly of claim 8 wherein said first and said second channel cooperatively form a fuel passage channel through which said fuel is pumped.
- 12. The fuel pump assembly of claim 8 wherein said second portion is tapered.
- 13. The fuel pump assembly of claim 8 wherein said second portion is stepped.
- 14. A method for increasing the efficiency of a fuel pump of the type having a selectively rotating impeller including a generally circular body and several blades of a certain thickness which project from said body, said method comprising the steps of:forming a thin inner portion on said circular body and a thick outer portion on said circular body; and reducing said thickness of said blades, effective to cause said thick outer portion of said body to be thicker than each of said blades.
- 15. The method of claim 14 further comprising the step of interconnecting said blades.
- 16. The method of claim 15 wherein each of said blades has a tip portion and wherein said step of interconnecting said blades comprises the step of interconnecting a member to said tip portion of each of said blades.
- 17. The method of claim 14 wherein said impeller is operatively placed into a chamber, said method for comprising the steps of tapering said chamber.
US Referenced Citations (15)