JP3100684B2 - Fuel pump - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump used in automobiles and the like, and more particularly to a Wesco fuel pump.

[0002]

2. Description of the Related Art Conventionally, this type of Wesco fuel pump includes a low-pressure side pump chamber and a high-pressure side pump chamber each having an impeller, and a substantially C-shaped low-pressure side pump formed by each pump chamber and each impeller. A fuel passage and a high-pressure side fuel passage;
A fuel inlet that communicates with the beginning of the low-pressure fuel passage; a communication hole that communicates the end of the low-pressure fuel passage with the beginning of the high-pressure fuel passage; and a fuel outlet that communicates with the end of the high-pressure fuel passage. Is known. In order to prevent the supply of fuel by vapor such as fuel vapor generated in the pump chamber, that is, to prevent a phenomenon such as a vapor lock, the low-pressure side fuel passage and the outside of the pump chamber are provided on the wall of the low-pressure side pump chamber. There is an apparatus in which a communicating vapor jet is provided, and the vapor is discharged outside the pump chamber from the discharging jet. Such a conventional fuel pump is disclosed, for example, in Japanese Utility Model Application Laid-Open No. 63-16038, which was previously proposed by the same applicant.
No. 7 proposes this. One-stage fuel pumps provided with a vapor discharge jet are disclosed in, for example, JP-A-60-79193 and JP-A-62-21.
There is one disclosed in Japanese Patent No. 4294 or the like.

[0003]

As described above, conventionally, even in a Wesco type two-stage fuel pump, the vapor discharge jet is provided in the first stage, that is, the low-pressure side fuel passage and the pump, similarly to the one-stage fuel pump. It is common to provide such that it communicates with the outside. However, depending on various conditions such as the discharge pressure of the pump, the number of revolutions of the impeller, the fuel used, and the fuel temperature, the vapor may not be completely discharged from the vapor discharge jet and may pass downstream. Therefore, in the worst case, the amount of vapor generated increases as the fuel temperature increases, and the second stage, that is, the high-pressure side fuel passage is closed by the vapor,
There is a possibility that the discharge flow rate of the fuel decreases and vapor lock occurs. For this reason, in order to prevent the vapor lock, generally, the rotation speed of the impeller is increased in view of a decrease in the discharge flow rate at high temperature, but in this case, the pump noise increases due to the high rotation speed. However, there is a problem that fuel efficiency is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a Wesco type two-stage fuel pump in which a high pressure side fuel cannot be completely discharged from a vapor discharge jet in a low pressure side fuel passage. An object of the present invention is to provide a fuel pump capable of preventing a vapor lock caused by a vapor passing through a fuel passage.

[0005]

A fuel pump according to the present invention for solving the above-mentioned problems has a substantially C-shape formed by a low-pressure pump chamber and a high-pressure pump chamber each having an impeller, and each pump chamber and each impeller. A low-pressure side fuel passage and a high-pressure side fuel passage, a fuel intake port communicating with a start end of the low-pressure side fuel passage, and a communication hole communicating with an end of the low-pressure side fuel passage and a start end of the high-pressure side fuel passage, A fuel discharge port communicating with the end of the high-pressure side fuel passage, wherein a wall for the low-pressure side pump chamber is provided with a vapor discharge jet communicating with the low-pressure side fuel passage and the outside of the pump chamber. the both the partition wall between the pump chamber jet returning vapor communicating is provided the low-pressure fuel passage and the high pressure side fuel passage, jet returning the vapor is
Is communicated to the low pressure side fuel passage upstream of said vapor discharge jet of the low-pressure fuel passage.

[0006]

According to the above means, the fuel pumped from the fuel suction port passes through the low pressure side fuel passage by the rotation of the impeller to the high pressure side fuel passage through the communication hole, and then passes through the fuel passage to the high pressure side. It is discharged from the fuel passage . The vapor generated in the low-pressure side fuel passage is discharged outside the pump chamber by the vapor discharge jet. Further, the vapor that cannot be completely discharged by the vapor discharge jet flows into the high pressure side fuel passage together with the fuel, and is returned from the vapor return jet to the low pressure side fuel passage due to a pressure difference between the two fuel passages. The gas is discharged from the discharge jet to the outside of the pump chamber. The low-pressure side fuel passage is
With the upstream side downstream from the return jet
Communicates two vapor discharge jets located downstream
Good to do. In addition, the impeller installed in the low-pressure side pump room
An opening hole is formed in the nozzle, and the vapor return jet communicates
The impeller against the partition wall between the two pump chambers
And the other wall of the low pressure side pump chamber located on the opposite side
In which a jet for vapor discharge is communicated,
The vapor discharge jet is connected to the impeller opening hole.
It is good to arrange on the same circumference line as the circumference line located.

[0007]

An embodiment of the present invention will be described with reference to the drawings. [Embodiment 1] First, an outline of a fuel pump will be described with reference to FIG. The motor part 2 is incorporated in the upper part of the cylindrical metal housing 1, and the pump part 3 is incorporated in the lower part thereof. A motor cover 5 made of synthetic resin is attached to an upper end surface of the housing 1. A pump cover 6 made of synthetic resin, a plate 24 and a pump body 7 are attached to a lower end surface of the housing 1. A motor chamber 8 is formed between the motor cover 5 and the pump cover 6 in the housing 1, and a high-pressure chamber-side pump chamber 9 b is formed between the pump cover 6 and the plate 24. A low-pressure chamber-side pump chamber 9 a is formed between the pump chamber 9 and the body 7. The plate 24 forms a wall that partitions the two pump chambers 9a and 9b according to the present invention.

In the motor section 2, the motor chamber 8
Is provided with an armature 10. The upper and lower ends of the shaft 12 of the armature 10 are
And it is rotatably supported by the pump cover 6 via bearings 13 and 14, respectively. A pair of magnets 15 are fixed to the inner peripheral surface of the housing 1 at a predetermined interval from the outer peripheral surface of the armature 10. A brush 16 slidably in contact with a commutator 10 a of the armature 10 is incorporated in the motor cover 5 in a state where the brush 16 is urged by a spring 17. Brush 16
Is electrically connected to an external connection terminal (not shown) via the choke coil 18. The motor cover 5 is provided with a fuel outlet 20 for connecting, for example, a fuel supply pipe (not shown) to a fuel injection valve of an automobile engine. A check valve 21 for preventing backflow of fuel is incorporated in the fuel outlet 20 in a state where the check valve 21 is urged in a closing direction by a spring 22.

In the pump section 3, an impeller 25 is provided in each of the pump chambers 9a and 9b. The two impellers 25 are connected to the lower end of the shaft 12 of the armature 10, and
Is driven to rotate. Each impeller 25
Has a disk shape as shown in a plan view in FIG.
The blades 25a are formed by a large number of grooves 25b provided on the outer peripheral portions of the front and back surfaces. In the impeller 25, an appropriate number (six in the figure) of opening holes 25c are formed on the inner and outer circumferential lines at substantially equal intervals.

In FIG. 2, a fuel inlet 26 is provided in the pump body 7 and a fuel outlet 27 is provided in the pump cover 6. The pump chambers 9a and 9b and the impellers 25 form a substantially C-shaped low-pressure fuel passage 30a and a high-pressure fuel passage 30b, respectively. The low pressure side fuel passage 30a is connected to the pump body 7
The high-pressure side fuel passage 30 b is formed so as to extend over the plate 24 and the pump cover 6. Further, a start end of the low-pressure fuel passage 30a is communicated with the fuel inlet 26, an end of the low-pressure fuel passage 30a is communicated with a start end of the high-pressure fuel passage 30b through a communication hole 28, and 3
The end of Ob is communicated with the fuel outlet 27, and the spiral from the fuel inlet 26 to the fuel outlet 27 is communicated. Although the fuel inlet 26, the fuel outlet 27, and the communication hole 28 are shown as being on the same line in FIG. 2, they actually have a positional relationship shifted from each other by a predetermined angle.

Next, regarding the shapes of the wall surfaces of the pump body 7, the plate 24 and the pump cover 6 forming the fuel passages 30a and 30b, FIG. This will be described in detail with reference to FIGS. As shown in FIG. 1, a lower passage groove 31 that forms a substantially lower half of the low-pressure fuel passage 30 a is provided on a wall surface (upper surface) of the pump body 7. As shown in a plan view in FIG. 3, the passage groove 31 has an angle θ (about 250 in this example) in the flow direction from the fuel inlet 26.
The range of (°) is slightly wider than the suction port 26, and from the end to the portion facing the communication hole 28, the width is about half the narrow width and about half the shallow depth of the wide part. Thus, it is formed continuously. Further, the outer peripheral edge of the lower passage groove 31 is formed in a series, and a step portion 32 is formed on the inner periphery thereof by changing the width. As shown in FIGS. 1 and 3, a rising wall 7 a having a height substantially equal to the thickness of the impeller 25 is formed in an annular shape on the outer peripheral edge of the pump body 7.

As shown in FIG. 1, an upper passage groove 33 which forms a substantially upper half of the low-pressure fuel passage 30a is provided on the lower wall surface (lower surface) of the plate 24. I have. The passage groove 33 has a substantially symmetric shape with the lower passage groove 31 as shown in a bottom view in FIG. The communication hole 28 is formed in a substantially elliptical shape that is long in the circumferential direction of the plate 24.

As shown in FIG. 1, a lower passage groove 35 that forms a substantially lower half of the high-pressure fuel passage 30b is provided on the upper wall surface (upper surface) of the plate 24. . This passage groove 35 has a width substantially equal to the narrow width of the passage grooves 31 and 33 from the communication hole 28 to the portion facing the fuel discharge port 27 as shown in a plan view in FIG. Is formed.

As shown in FIG. 1, the high pressure side fuel passage 3 is provided on the wall surface (lower surface) of the pump cover 6.
An upper passage groove 37 that forms a substantially upper half portion of Ob is provided. The passage groove 37 is formed substantially symmetrically with the lower passage groove 35 of the plate 24 as shown in a bottom view in FIG. As shown in FIGS. 1 and 6, a rising wall 6 a having a height substantially equal to the thickness of the impeller 25 is formed in an annular shape on the outer peripheral edge of the pump cover 6. The fuel outlet 27 is also connected to the communication hole 28.
Similarly, the cover 6 is formed in a substantially elliptical shape that is long in the circumferential direction.

The pump body 7 has the structure shown in FIG.
As shown in FIG. 3, at the inner peripheral edge of the lower passage groove 31, the angle θ1 is set in the downstream direction from the fuel intake port 26.
At a position (about 120 ° in this example), a vapor discharge jet 40 penetrating the bottom surface of the body is opened. In addition to the vapor discharge jet 40, a vapor discharge jet 41 adjacent upstream of the step 32 is provided.
Is open. In addition, both discharge jets 40, 41
Are located on the same circumferential line as the circumferential line where the outer opening hole 25c of the impeller 25 is located, and the opening hole 25c
It has almost the same caliber as.

As shown in FIGS. 1 and 5, the plate 24 has a downstream angle θ2 (about 90 ° in this example) from the communication hole 28 at the inner peripheral edge of the lower passage groove 35 on the upper surface thereof. ) Is located at the upper passage groove 3 on the lower surface.
A vapor return jet 43 penetrating through 3 is opened. That is, the vapor return jet 43 is provided in the low pressure side fuel passage 30a.
Is communicated upstream. In addition, the opening area of the communication hole 28 is designed to prevent the flow rate from decreasing, and to prevent the high-pressure side fuel passage 30 from decreasing.
It is desirable to make the value sufficiently larger, for example, 1.5 times or more than the value obtained by adding the sectional area of b and the opening area of the vapor return jet 43.

In the fuel pump, an impeller 25 of the pump unit 3 is rotated as the motor unit 2 is driven by a battery (not shown) of an automobile or the like as a power source. As a result, the fuel in the fuel tank is pumped from the fuel inlet 26 into the low-pressure side pump chamber 9a. The pumped fuel is supplied to the low pressure side fuel passage 30 by rotation of the impeller 25.
a through the communication hole 28 to the high-pressure side fuel passage 30b, is discharged from the fuel discharge port 27 of the pump cover 6 through the fuel passage 30b and enters the motor chamber 8, and then the fuel outlet of the motor cover 5 Discharged from 20.

According to the above-described fuel pump, the vapor generated in the low-pressure side fuel passage 30a is discharged out of the pump chamber by the vapor discharge jets 40 and 41. Further, the vapor that cannot be completely discharged by the vapor discharge jets 40 and 41 flows into the high pressure side fuel passage 30b together with the fuel, and the low pressure side fuel flows from the vapor return jet 43 due to the pressure difference between the two fuel passages 30a and 30b. Passage 3
After returning to 0a, the fuel is discharged from the vapor discharge jet 40 to the outside of the pump chamber. The vapors that cannot be completely discharged by the vapor discharge jets 40 and 41 include a vapor generated downstream of the discharge jet 41, a vapor generated when passing through the passage hole 28, and the like. Therefore, it is possible to prevent the vapor from being locked by the vapor that has not completely been discharged from the vapor discharge jets 40 and 41 in the low-pressure fuel passage 30a and has passed through the high-pressure fuel passage 30b. For this reason, it is not necessary to increase the rotation speed of the impeller 25 in anticipation of a decrease in the discharge flow rate at high temperatures as in the related art, and it is possible to avoid problems such as an increase in pump noise and deterioration in fuel efficiency.

According to the present embodiment, the provision of the vapor discharge jet 41 downstream of the vapor discharge jet 40 makes it possible to discharge the vapor more effectively than in the case where only one vapor discharge jet is provided. It is. It should be noted that any one of the vapor discharge jets 40 and 41 which is excluded is also included in the technical scope of the present invention. In addition, since the two ejection jets 40 and 41 are located on the same circumferential line as the circumference where the opening 25c outside the impeller 25 is located, the vapor returned from the vapor returning jet 43 passes through the opening 25c. Jet 40, 41
It flows smoothly to and is discharged. Also each jet 4
Since 0, 41, and 43 are located in the inner peripheral portion of the fuel passage where the vapor is easily collected, the discharge and return of the vapor are effectively performed. Further, since the stepped portion 32 is provided in the lower passage groove 31 of the pump body 7 and the vapor discharging jet 41 is provided adjacent to the upstream thereof, the vapor blocked by the stepped portion 32 is removed by the vapor discharging jet 41. Is discharged smoothly from

Embodiment 2 Embodiment 2 will be described.
Since the present embodiment is a partial modification of the embodiment, different configurations will be described in detail, and portions considered to be the same or equivalent to those of the first embodiment will be denoted by the same reference numerals in the drawings and will be repeated. Description is omitted. In the following and subsequent embodiments, the same description will not be repeated. In this example, as shown in the plan view of the plate in FIG.
The width of the range (about 90 ° in this example) is wide, and the width from the end to the portion facing the fuel discharge port 27 is formed to be narrow, and a step portion 39 is provided on the inner periphery by changing the width. A vapor return jet 43 is opened adjacent to the upstream of the step portion 39. For this reason, the vapor going to flow through the high-pressure side fuel passage 30 b by the step portion 39 can be positively returned from the vapor return jet 43 to the low-pressure side fuel passage 30 a.

[Embodiment 3] In this embodiment, as shown in the plan view of the pump body in FIG. 9, the lower passage groove 31 of the pump body 7 of the embodiment 1 is wider again downstream of the step portion 32. It is a width.

[0022]

According to the present invention, the vapor that cannot be completely discharged by the vapor discharge jet flows to the high pressure side fuel passage together with the fuel, and the low pressure side by the pressure difference between the two fuel passages from the vapor return jet. After being returned to the fuel passage, the fuel is discharged from the vapor discharge jet to the outside of the pump chamber, so that the vapor in the fuel is almost discharged, so that the vapor lock can be effectively prevented.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main part of a fuel pump according to a first embodiment.

FIG. 2 is an overall sectional view of a fuel pump.

FIG. 3 is a plan view of a pump body.

FIG. 4 is a bottom view of the plate.

FIG. 5 is a plan view of a plate.

FIG. 6 is a bottom view of the pump cover.

FIG. 7 is a plan view of the impeller.

FIG. 8 is a plan view of a plate showing the second embodiment.

FIG. 9 is a plan view of a pump body showing a third embodiment.

[Explanation of symbols]

 9a Low-pressure side pump chamber 9b High-pressure side pump chamber 25 Impeller 26 Fuel suction port 27 Fuel discharge port 28 Communication hole 30a Low-pressure side fuel passage 30b High-pressure side fuel passage 40, 41 Vapor discharge jet 43 Vapor return jet

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Hei 3-25856 (JP, U) Japanese Utility Model 36-20854 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) F04D 5/00 F02M 37/08 F02M 37/20

Claims (3)

(57) [Claims] A low-pressure side pump chamber and a high-pressure side pump chamber each having an impeller; a substantially C-shaped low-pressure side fuel passage and a high-pressure side fuel passage formed by each pump chamber and each impeller; A fuel inlet that communicates with the start end of the fuel passage, a communication hole that communicates the end of the low-pressure fuel passage and the start end of the high-pressure fuel passage, and a fuel outlet that communicates with the end of the high-pressure fuel passage. In the fuel pump, a vapor discharge jet communicating the low pressure side fuel passage and the outside of the pump chamber is provided on a wall of the low pressure side pump chamber, and a high pressure side fuel is provided on a partition wall between the two pump chambers. jet returning vapor is provided for communicating said the passage low-pressure fuel passage, jet returning the vapor, the low pressure upstream of <br/> the vapor discharge jet of the low-pressure fuel passage Side fuel
A fuel pump, which is connected to a passage . 2. The fuel pump according to claim 1, wherein:
In the low pressure side fuel passage, downstream from the vapor return jet
Two vapors located upstream and downstream of each other
-A fuel pump characterized by communicating with a discharge jet
H. 3. The fuel pump according to claim 1, wherein:
Therefore, an opening hole is formed in the impeller arranged in the low-pressure side pump chamber.
Both pons formed and communicated with the vapor return jet
Opposite side with the impeller between the partition walls between
Vapor discharge to the other wall of the low pressure side pump chamber located at
A discharge jet communicating with said vapor,
The discharge jet is placed on the circumference of the impeller
Characterized by being arranged on the same circumferential line as the line
H.