JPS63302197A - Fuel pump device contained in fuel tank - Google Patents

Abstract

PURPOSE:To effectively discharge vapor outward without deteriorating dischargeability of a pump by providing an air hole in the vicinity of radial stepped parts arranged at specified positions of a fuel circular flow passage formed along an impeller. CONSTITUTION:Radial stepped parts 13a, 14a are arranged at specified positions of a circular flow passage 8, and in the vicinity of the stepped parts an air hole 16 for discharging vapor to the outside of a reproducing pump 3 is provided. When vapor generated in a pump chamber 6 moves from an inlet port 9 to a discharge port 10 through the passage 8, the speed of vapor is reduced by means of the stepped parts 13a, 14a, thereby the pressure in the vicinity thereof is partially boosted. Vapor is then discharged effectively to the outside of the reproducing pump 3, that is, into a fuel tank from the air hole 16. Accordingly, good dischargeability of the pump is secured, even when a temperature is high or the atomic pressure decreases, and the generation of vapor lock can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to the reinstallation of a fuel pump with a built-in fuel tank using a turbine-type regeneration pump capable of obtaining high fuel pressure.

[Prior Art] Conventionally, positive displacement roller vane pumps have been the mainstream pumps for fuel pump devices with built-in fuel tanks installed in vehicle fuel tanks, but they have high discharge pulsation pressure, are noisy, and have a structural problem. In recent years, turbine-type regeneration pumps have been installed because they are complicated and have high costs.

Since this type of pump is of a non-displacement type, the discharge pulsating pressure is very low, which has the advantage of reducing noise, reducing the number of pump components, and simplifying the structure. However, when this regenerating pump is used in a vehicle fuel pump, the motor frequency becomes high in order to satisfy the pump performance, and the fuel is stirred in a thin layer at high speed in the pump chamber, making cavitation more likely to occur. Especially when the temperature is high or the pressure is low, the fuel in the pump chamber may vaporize and cause vapor lock of the pump.

To address these issues, for example, U.S. Patent No. 3.259.0
As shown in No. 72 specification or U.S. Pat. No. 3,418,991, FIG. FIG. 2 is a circumferential cross-sectional developed view of a pump chamber and a fuel pressure distribution characteristic diagram at each position inside the pump chamber. 91st! In I, a pump chamber is formed by the pump casing 24 and an end cover 25 that closes the lower end side of the casing 24, and an impeller 27 is disposed within this pump chamber.

An annular flow path formed along this impeller 27? A starting point of B communicates with a suction hole 29 provided in the end cover 25, and an end point of the flow path 28 communicates with a discharge hole 30 provided in the pump casing 24. Reference numeral 36 is a vent hole for discharging the vapor 26 to the outside of the pump, and is provided in the end cover 25. Here, the broken line X is at room temperature (fuel temperature is 20°C ±
IO'c), solid line Y is at high temperature (fuel temperature is 50°C ± 1
The rotation of the impeller 27, which is the pressure distribution characteristic curve in each pump chamber at 0°C), causes the suction hole 29 to change as shown by the arrow.
The pressure of the fuel 31 flowing from the fuel 31 is gradually increased in the process of reaching the discharge hole 30, and the fuel 31 is discharged at the maximum discharge pressure at the discharge hole 30. Note that the suction hole 29 becomes under negative pressure.

The fuel (gasoline) 31 at high temperature is approaching a boiling state, and paper 26 is generated due to the sudden pressure drop at the suction hole 29, and the fuel 31 is agitated by the impeller 27, causing the paper 26 to be generated. further promoted. Therefore, the fuel 31 containing the paper 26 is pressurized while moving through the flow path 2B in the pump chamber.
If the structure is such that the paper 26 cannot be efficiently discharged to the outside of the pump, the pump's discharge performance will be degraded as shown by the solid line Y. Therefore, the paper 26 can be efficiently discharged to the outside of the pump to improve the pump's discharge performance. Therefore, the setting position and size of the ventilation hole 36 are important.

Here, FIG. 1O is a diagram of the fluid state in the pump chamber at high temperature, and the fuel 31 containing the paper 26 that has flowed in from the suction hole 29 is caused by the centrifugal force caused by the rotation of the impeller 27, and the fuel 31a with a high vapor density is The fuel 31b having a low vapor density is pushed toward the inner circumferential wall 33 of the flow path 28, and the fuel 31b having a low vapor density is pushed toward the outer circumferential wall 34 of the flow path 28. As this fuel 313 with a high vapor density moves through the flow path 28, it is converged on the inner circumferential side wall 33 near point E, and the inside of the flow path 28 from this point E to the discharge part 32 is filled with fuel with a low vapor density. 3
Filled with 1b. The fuel 31a with high vapor density is on the inner circumferential side! ! 33, the flow velocity of the fuel 31a is reduced and the pressure is partially increased.

Therefore, by providing the ventilation hole 36 slightly before the point E, the paper 26 can be efficiently discharged to the outside of the pump, and the discharge performance of the pump can be improved.

[Problems to be Solved by the Invention] However, the amount of paper 26 generated and the increase in fuel temperature are not constant due to the driving condition of the vehicle, the structure of the vehicle, etc. Or it will move to the discharge part 32 side, and the set ventilation hole 36
At the position, the paper 26 cannot be discharged to the outside of the pump, and the inside of the pump chamber is filled with the paper 26, reducing the discharge performance of the pump, and furthermore, the discharge amount may become zero, leading to paper lock. For this reason, the structure is such that the position of the vent hole 36 is moved to a position on the discharge part 32 side where the internal pressure of the pump is high, so that even if the amount of vapor 26 generated increases, the vapor 26 can be discharged to the outside of the pump. There is. However, in this case, since the vent hole 36 is provided at a position where the internal pressure of the pump is high, the fuel 31 often leaks from the vent hole 36, especially at room temperature.

A problem occurs in which the ejection performance of the product decreases. Note 1 ventilation hole 36
It is also possible to reduce the hole diameter size to prevent the pump's discharge performance from deteriorating, but in this case, the passage resistance of the ventilation hole 36 makes it difficult for the vapor 26 to pass through, and the vapor 26 is efficiently discharged to the outside of the pump. Therefore, in order to improve the discharge performance of the pump, it is necessary to increase the number of revolutions of the pump or increase the diameter of the impeller 27 to increase the amount of work of the pump. In the former case, cavitation is more likely to occur, and problems such as decreased durability and increased noise occur; in the latter case, the pump load increases, the motor current increases, and the diameter of the impeller 27 increases. This causes a problem in that the entire pump device becomes larger.

The present invention was devised in view of the above-mentioned conventional problems, and aims to efficiently discharge paper to the outside of the pump without reducing the discharge performance of the pump by improving the flow path inside the pump chamber of the regeneration pump. The purpose of the present invention is to provide a fuel pump device with a built-in fuel tank.

[Means for Solving the Problems] In order to achieve the above object, a fuel pump device with a built-in fuel tank according to the present invention has a configuration including: an impeller disposed in a pump chamber of a regeneration pump driven by a motor; An annular flow path formed along this impeller, a suction hole and a discharge hole provided at the start and end points of this annular flow path, respectively, for sucking and discharging fuel; In a fuel pump device installed in a vehicle tank and equipped with a vent hole for discharging transferred vapor to the outside of the pump, a radial stepped portion is provided at a predetermined position of the annular flow path. , the ventilation hole is provided near the stepped portion.

[Operation] According to the present invention having the above configuration, when the vapor generated in the pump chamber moves within the annular flow path from the suction hole to the discharge hole in the pump chamber, the radial step provided in the flow path Since the flow rate of the vapor is reduced by the part and the pressure in the vicinity of the step in the radial direction is partially increased, the vapor can efficiently flow outside the pump, that is, into the fuel tank, through the vent hole provided in the vicinity of the step. be discharged. Therefore, good discharge performance of the pump is ensured even when the temperature is high or the pressure decreases, and paper lock can be prevented from occurring.

[Example] The present invention will be described below based on an example shown in FIGS. 1 to 7.

FIG. 1 is a vertical cross-sectional view of a fuel pump device, in which 1 is a fuel tank built-in fuel pump device installed in a vehicle fuel tank (not shown), and includes a motor 2 and a regeneration pump 3 driven by the motor 2. It has a structure in which the two are connected together. 2a is an amateur, 2b is the amateur 2a
This is the rotor shaft.

A pump chamber 6 is formed by the pump casing 4 and an end cover 5 that closes the lower end side of the pump casing 4, and within this pump chamber 6 is an impeller 7 that is non-rotatably attached to the lower end of the rotor shaft 2b. Arrange.

Reference numeral 8 denotes an annular flow path formed along the impeller 7, and suction holes 9.8 are provided at the start and end points of the flow path 8 to suck in and discharge fuel, respectively. A discharge hole 10 is provided. The suction hole 9 is formed in the end cover 5, and the discharge hole 10 is formed in the pump casing 4 and communicates with the inside of the motor 1.

Fuel flows into the annular flow path 8 from the suction hole 9 due to the pump action caused by the rotation of the armature 2a and the rotation of the impeller 7 that is non-rotatably attached to the rotor shaft 2b. The inflowing fuel is pressurized by the fluid friction force generated by the rotation of the impeller 7, passes through the inside of the motor 2 from the discharge hole IO, and is forced into a pipe (not shown) from the discharge pipe 11.

Next, FIG. 2 is an enlarged sectional view taken along line A-A in FIG. 1, and FIGS. 3, 4, and 5 are enlarged sectional views taken along line BB and C-C in FIG. 2, respectively. FIG.

In FIGS. 2 to 5, the fuel flowing from the suction hole 9 provided in the end cover 5 spirals inside the annular flow path 8 whose cross-sectional area is approximately constant from the suction hole 9 to the discharge part 12. It turns and moves after being boosted.

Here, an inner circumferential side wall 1 forming a part of the annular flow path 8
3 and the outer peripheral side wall 14 each have a cross-sectional shape that is inclined so as to widen upward from the bottom surface 15, and are asymmetrical. In the flow path region from position F of the suction hole 9 to position G forming an angle of θ1 with respect to the axial center position 0 of the impeller 7, the inclination angle of the inner peripheral side wall 13 is set at α as shown in FIG. The inclination angle of the outer peripheral side wall 14 is β
(α × β) Also, from the G position to the discharge part 1
In the flow path region forming an angle θ2 with respect to the axis center position 0 up to the H position of 2, the inclination angle of the inner circumferential side wall 13 is β and the inclination angle of the outer circumferential side wall 14 is α, as shown in FIG.

That is, at a predetermined position of the flow path 8 [the inner peripheral side that forms a part of the flow path 8 at G! 13 and the outer peripheral side wall 14 are changed in cross-sectional shape. Therefore, in the above G position, as shown in FIGS.
As shown in the figure, a radial stepped portion 131. ■−
is formed, and a vent hole 16 for discharging vapor to the outside of the pump is provided near the stepped portion 13a. In this embodiment, the radial width dimension of the bottom surface 15 is made the same throughout the entire flow path area in order to make the cross-sectional area of the annular flow path 8 almost constant over the entire flow path area. θ,
= 120°, angle θ2 = 190°, inclination angle α = 30°, inclination angle β = 45°, and the dimensions of the radial step portions 13a and 14a are approximately 0.17In11.
It was set to 1.

FIG. 6 is a characteristic diagram of the discharge flow rate with respect to the fuel temperature of this embodiment and the conventional example, in which the horizontal axis represents the fuel temperature and the vertical axis represents the discharge flow rate.

The solid line X is the characteristic of this example, and the fuel temperature is approximately 50°
Although the discharge flow rate gradually decreases when the temperature exceeds 70＠
It was confirmed that vapor lock did not occur in case C as well. Furthermore, at high temperatures, the fuel pressure distribution at each position inside the pump chamber of this embodiment is such that the characteristic curve Z suddenly rises from the position of the vent hole 16, as shown by the two-dot chain line Z in FIG. Even when compared with the broken line, which is the characteristic curve at room temperature, the characteristics are only slightly deteriorated.

The vapor generated in the pump chamber 6 when the temperature is high or when the pressure drops moves along with the fuel in the flow path 8 due to the rotation of the impeller 7, and the centrifugal force caused by the rotation of the impeller 7 causes the fuel with high vapor density to Although it is pushed toward the inner peripheral side wall 13 side of the flow path 8, the flow rate of the fuel with high vapor density is reliably and effectively reduced by the step portion 13a in the radial direction. The vapor is efficiently discharged to the outside of the pump, that is, into the fuel tank.
For this reason, good discharge performance of the pump is ensured even at high temperatures or low atmospheric pressure, and paper lock can be prevented from occurring. The broken line y in Fig. 6 is the characteristic of the conventional example, and shows that when the fuel temperature exceeds approximately 50°C, the discharge flow rate decreases rapidly, and finally the discharge flow rate reaches zero, leading to paper lock. There is.

Next, FIG. 7 is a pump restart characteristic diagram of this embodiment. This characteristic diagram shows that the power supply to the motor that drives the fuel pump is temporarily turned 0FFL while fuel is being pumped at a high temperature, and the pumping of fuel from the fuel pump is temporarily stopped for T seconds (approximately 20 to 20 seconds).
This indicates how many seconds after which the fuel can be pumped when the motor is turned on after 60 seconds). According to this embodiment, the fuel can be pumped after t=approximately 3 to 5 seconds. It was confirmed that no locking occurred. This is because when the fuel pump stops, the inside of the pump chamber 6 and the inside of the motor 2 are rapidly reduced from the pumping pressure (for example, 2.6 k (/cm2) to near atmospheric pressure, so vapor generation becomes intense. This is because the vapor in the pump chamber 6 is efficiently discharged to the outside of the pump by the vapor removing action described above.

In this embodiment, the radial step portion 13a,
Although the dimension of 14a was set at about 0.17 mm, it was found that if this dimension was significantly different from the above value, the effect of the stepped portion 13a would be reduced. In other words, if it is too small, it will not be possible to effectively decelerate the fuel with high vapor density and the vapor will not be discharged efficiently, and if it is too large, the stepped portion 13a will act as a dam, causing turbulence in the fuel and causing vapor to flow. This is because it occurs. In addition, in FIG. 2, the inner peripheral side 11 in the flow path region from the F position to the G position
13 is β (45”), the inclination angle of the outer peripheral side wall 14 is α (30°), and the inclination angle of the inner peripheral side wall 13 in the flow path region from the G position to the H position is α (30°). )
.

One step part 1 with the inclination angle of the outer peripheral side wall 14 being β (45°)
Although it is possible to provide a ventilation hole 16 near 4a,
It has been found that it is more effective to provide the ventilation hole 16 near the stepped portion 13a.

Here, the stepped portions 13a and 14a in the radial direction are the inner peripheral side wall 13 and the outer peripheral side! ! 14 to a predetermined extent W(
G rank! Although it was formed by varying the angle, from the axial center 10 of the impeller 7 to the inner circumferential side wall 13 and the outer circumferential side! ! 14
The radial length up to the predetermined digit 1! (G position) by changing the radial step portions 13a and 1.
Even if 4a is formed, the same effect can be obtained.

Next, FIG. 8 shows another embodiment of the present invention, and is an enlarged sectional view taken along line ^-A in FIG. 1, similar to FIG. 2.

In this embodiment, an annular flow channel 8 having a constant cross-sectional area is used.
Of the total flow path area of This is a flow passage cross-sectional area enlarged portion 17 in which the flow passage is expanded in the direction. The flow passage cross-sectional area enlarged portion +7 gradually decreases the flow passage cross-sectional area from the suction hole 9 side toward the discharge portion 12 side.
The structure is such that the position matches the constant cross-sectional area of the flow path.

Therefore, the average velocity of the fuel in the flow path in the area of the enlarged cross-sectional area of the flow path 17 following the suction hole 9 does not increase rapidly, but gradually increases, and therefore the static pressure in the predetermined area increases. A sudden drop can be prevented.

The amount of vapor generated in the fuel is reduced.

Incidentally, if the angle θ3 is too small, that is, if the predetermined channel area that becomes the channel cross-sectional area enlarged portion 17 is too small, the change in the channel cross-sectional area becomes rapid, and vapor is likely to occur. Also, the angle θ3 is too large and the J position is
As the pump approaches the position, the discharge flow rate of the pump increases, but the impeller 7
It was found that the driving torque of the pump increased and the pump efficiency decreased. From these results, it has been found that the above-mentioned effect can be achieved satisfactorily if the angle 03 is approximately 50° to 90''.

[Effects of the Invention] As described above, the fuel pump device with a built-in fuel tank according to the present invention improves the annular flow path of the regeneration pump, thereby reliably and efficiently transferring vapor to the outside of the pump without degrading the discharge performance of the pump. It is possible to prevent vapor lock from occurring, and also to reduce the size of the pump device, improve its durability, and reduce noise.

[Brief explanation of the drawing]

1 to 7 show an embodiment of a fuel pump device with a built-in fuel tank according to the present invention, FIG. 1 is a longitudinal sectional view of the fuel pump device, and FIG. 2 is a line 8-A in FIG. 1. 3, 4, and 5 are respectively an enlarged sectional view along the line B-B, an enlarged sectional view along the C-C line, and an enlarged sectional view along the D-D line in FIG. 2, and FIG. 6 is the fuel FIG. 7 is a characteristic diagram of discharge flow rate with respect to temperature, FIG. 7 is a pump restart characteristic diagram, FIG. 8 is an enlarged sectional view taken along the line A-A of FIG. 1 showing another embodiment of the present invention, and FIG. FIG. 10 is a circumferential cross-sectional developed view of the pump chamber of the pump, a fuel pressure distribution characteristic diagram inside the pump chamber, and a fluid state diagram inside the regenerating pump chamber at high temperatures. 1...Fuel pump device with built-in fuel tank. 2...Motor, 3...Regeneration pump, 6...
・Pump room, 7.27... impeller, 8.
28... Annular flow path, 9.29... Suction hole,
10.30...Discharge hole, 13.33...
・Inner peripheral side wall, 13a... radial step part,
14.34...Outer peripheral side wall, 14a...Radial step, 16.36...Vent hole, 1
7... Channel cross-sectional area enlargement section Patent applicant: Jidosha Electric Industries Co., Ltd., Mine 1-eup, Figure 2 +G: k%JL'! A60 Figure 9 Figure 9 Item 10 Procedures Amendment (Voluntary) 1986 6
May 8, 2, Title of invention Fuel pump device with built-in fuel tank 3, Relationship with the person making the amendment Patent applicant Postal code 245 Telephone 045 (851) 1231 (Main representative) Explanation column (1) Specification signature amend the claims as shown in the attached sheet. (2) One invention described in page 2, line 19 of the same book
The present invention is corrected. (3) "Mainstream" written in page 3, line 5 of the same book is corrected to "mainstream". (4) "Motor number of times" written on page 3, line 14 of the same book is corrected to "motor rotation number." (5) "Difference" written in lines 14 to 15 on page 6 of the same book is corrected to "difference." 2. Scope of Claims <1) An impeller disposed in a pump chamber of a regeneration pump driven by a motor, an annular flow path formed along the impeller, and a starting point of the annular flow path. A suction hole and a discharge hole are provided at each end point for sucking and discharging fuel, and a vent hole is provided for discharging vapor transferred together with the fuel into the annular flow path to the outside of the pump,
The fuel pump device installed in a vehicle fuel tank is characterized in that a radial stepped portion is provided at a predetermined position of the annular flow path, and the vent hole is provided in the vicinity of this stepped portion. Fuel pump device with built-in fuel tank. (2) The stepped portion in the radial direction is formed by changing the cross-sectional shapes of the inner circumferential side wall and the outer circumferential side wall of the annular channel, which constitute a part of the annular channel, at the predetermined positions. A fuel pump device with a built-in fuel tank according to claim 1, wherein the fuel pump device has a built-in fuel tank. (3) The radial step portion has a radial length from the axial center position of the impeller to the inner circumferential side wall and outer circumferential side wall of the flow path that constitutes a part of the annular flow path. A fuel pump device with a built-in fuel tank according to claim 1, characterized in that the fuel pump device is formed by changing each position. (4) According to any one of claims 1 to 3, a predetermined flow path region that does not reach the radial step from the suction hole is defined as a flow path cross-sectional area enlarged portion. The described fuel pump device with built-in fuel tank. (5) The predetermined flow path area that becomes the flow path cross-sectional area enlargement portion is an angular range area of approximately 50° to 90° from the position of the suction hole to the axial center position of the impeller. A fuel pump device with a built-in fuel tank according to claim 4.

Claims (5)

[Claims] (1) An impeller disposed inside the pump chamber of a regeneration pump driven by a motor, an annular flow path formed along the impeller, and fuel provided at the start and end points of the annular flow path. a suction hole and a discharge hole for suctioning and discharging the fuel, and a ventilation hole for discharging the vapor transferred together with the fuel into the annular flow path to the outside of the pump,
The fuel pump device installed in a vehicle fuel tank is characterized in that a radial stepped portion is provided at a predetermined position of the annular flow path, and the vent hole is provided in the vicinity of this stepped portion. Fuel pump device with built-in fuel tank. (2) The step portion in the radial direction is formed by changing the cross-sectional shapes of the inner circumferential side wall and the outer circumferential side wall of the annular channel, which constitute a part of the annular channel, at the predetermined positions. A fuel pump device with a built-in fuel tank according to claim 1. (3) The radial step portion has a radial length from the axial center position of the impeller to the inner circumferential side wall and outer circumferential side wall of the flow path that constitutes a part of the annular flow path. A fuel pump device with a built-in fuel tank according to claim 1, characterized in that the fuel pump device is formed by changing each position. (4) Any one of claims 1 to 3, characterized in that a predetermined flow path area that does not reach from the suction hole to the step portion in the radial direction is defined as a flow path cross-sectional area enlarged portion. The described fuel pump device with built-in fuel tank. (5) The predetermined flow path area that becomes the flow path cross-sectional area enlargement portion is an angular range area of approximately 50° to 90° from the position of the suction hole to the axial center position of the impeller. A fuel pump device with a built-in fuel tank according to claim 4.