JP2004108380A - Fuel supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device expected in keeping constant fuel suction capability. <P>SOLUTION: A vapor passage 181 communicating to a vent 180 is provided below a fuel pump 18, and a metal nozzle 182 is pressed and fixed to the lower end thereof. A throat 311 composing a jet pump which is a fuel suction mechanism 31 is provided at a position facing the metal nozzle 182. When fuel is injected from the metal nozzle 182, the fuel is sucked in the throat 311 from a suck-up pipe 312 of the jet pump. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a fuel supply device having a fuel pump.

燃料 There are various types of fuel pumps that supply fuel from the fuel tank to the engine, but there is a circumferential flow type fuel pump that is mounted inside the fuel tank and driven by a motor. The in-tank type fuel pump is covered by a sub-tank disposed in the fuel tank, and the sub-tank stores fuel sucked into the fuel pump.

(4) A check valve is provided at the bottom of the sub-tank as a means for initially guiding the fuel into the sub-tank. This check valve allows the fuel in the fuel tank to flow into the sub-tank when the fuel level in the fuel tank is higher than the fuel level in the sub-tank. When the fuel level is lower than the fuel level, it is a static fuel introduction means for preventing the fuel in the sub tank from flowing back to the fuel tank.

中 During operation of the fuel pump, the fuel in the fuel tank is pumped into the sub-tank by dynamic fuel introduction means such as a jet pump that uses a part of the power of the fuel pump.

For example, in Patent Document 1, as a fuel suction mechanism, the fuel at the bottom of the fuel tank is pumped into the sub-tank by using the fluid energy of the return fuel returned to the fuel tank out of the fuel discharged from the fuel pump. It is equipped with a jet pump.
JP-A-3-253760

However, in the method of using the return fuel for sucking up the fuel, when the fuel consumption in the engine increases, the phenomenon occurs that the return fuel decreases and the power of the fuel suction mechanism decreases.

(4) An object of the present invention is to provide a fuel supply device that can always expect a constant fuel suction capacity in view of the above-described problems of the related art.

The present invention includes the following technical means to achieve the above object.

That is, according to the first and second aspects of the present invention, a turbine type fuel pump disposed in a fuel tank and for pumping fuel to a fuel consuming device outside the fuel tank, and containing the turbine type fuel pump and sucking the fuel into the fuel pump. And a jet pump for pumping the fuel in the fuel tank into the sub-tank, wherein the jet pump has an air hole of the turbine fuel pump. A vapor passage communicating with the nozzle, a nozzle provided at an end of the vapor passage, and a throat provided at a position facing the nozzle, wherein the throat is driven by using fuel ejected from the air hole. Features.

Particularly, the invention according to claim 2 is characterized in that the nozzle and the throat are placed horizontally.

According to the present invention, by employing the above technical means, the jet pump can be driven by the fuel from the air hole of the turbine fuel pump, and the fuel in the fuel tank can be pumped into the sub tank. Therefore, as long as the discharge pressure of the fuel is constant, a constant fuel suction capacity can always be expected.

Hereinafter, embodiments and reference examples of the present invention will be described with reference to the drawings.

(Reference Example 1)
A fuel supply device according to Reference Example 1 will be described with reference to FIGS. In this embodiment, as shown in FIG. 1, a fuel tank 11 for storing fuel 8, a fuel pump 17 disposed in the fuel tank 11 for pumping the fuel 8 to an engine outside the fuel tank 11, and a fuel pump 17 are provided. A sub-tank 12 for storing fuel 8 sucked into a fuel pump 17; and a fuel tank 11 provided at a lower portion of the sub-tank 12 for introducing the fuel 8 in the fuel tank 11 to the sub-tank 12 while fuel 8 in the sub-tank 12 is stored in the fuel tank 11. A fuel supply device having a check valve for preventing the fuel from flowing out; It is.

The sub-tank 12 has a diaphragm valve 25 communicating with a discharge pipe line 172 connecting the discharge port 171 of the fuel pump 17 and the engine, and an opening 201 (FIG. 2) communicating with the atmosphere by the operation of the diaphragm valve 25 at the upper part. And a fuel tank 20 having an open bottom and a bottom having a bottom 202 opening below the liquid level of the fuel 8.

The diaphragm valve 25 closes the opening 201 (FIG. 2) of the fuel storage tank 20 when the fuel pump 17 is not operating, and opens the opening 201 by the fuel pressure of the discharge pipe 172 when the fuel pump 17 is operating. The fuel suction mechanism 30 is a jet pump that pumps up the fuel in the fuel tank 11 using fluid energy of a part of the fuel discharged from the fuel pump 17.

Each is described in detail below. As shown in FIG. 1, a flange 44 is provided above the sub tank 12, and a main tube 441, a fuel return tube 442, and an electric circuit connector 443 are arranged on the flange 44. Is established. The sub tank 12 has a projection area slightly smaller than the projection area of the flange 44.

The supporter 13 forming the upper surface of the sub-tank 12 has a joint portion 131 with the fuel pump 17 and an insertion port 132 of the return tube 442, the diaphragm valve 25 is mounted on the upper surface thereof, and the fuel storage tank 20 is located below. Installed. A return pipe 45 connected to a return tube 442 via an O-ring 133 and formed with a jet pump nozzle 301 described below is provided directly below the insertion port 132.

The supporter 13 is integrated with the body 121 of the sub tank 12 by snap-fit connection. The other end of the joint 131 of the supporter 13 is connected to the main tube 441 of the flange 44 via a sliding seal 134, and a residual pressure holding valve 135 is provided at the connection. The residual pressure holding valve 135 is closed by the flow of the fuel. A branch pipe 136 branches from the middle of the joint portion 131 and is connected to the diaphragm valve 25. The hose forming the branch pipe 136 is a fluoro rubber or 11 NY, 12 NY resin hose.

吸 A suction port 173 of the fuel pump 17 is provided in the fuel storage 121 at the bottom of the sub tank 15. An impeller 175 is provided above the suction port 173, and the impeller 175 is connected to a drive shaft of the motor 176 above. On the other hand, a discharge port 171 at the other end of the fuel pump 17 is connected to a joint 131 of the supporter 13 via a seal ring 174.

The diaphragm valve 25 is mounted on the upper surface of the supporter 13 as shown in FIG. 2, and the cover 251 and the diaphragm 252 constitute a pressure chamber 253. The pressure chamber 253 is connected to the joint 131 via a branch pipe 136. A plate 254 is attached to the bottom surface of the diaphragm 252, and a shaft 255 is fixed to the plate 254.

The plate 254 and the shaft 255 move up and down together with the diaphragm 252. The shaft 255 penetrates the shaft hole 204 of the upper surface 203 of the fuel storage tank 20, and a lower end of the shaft 255 protruding into the fuel storage tank 20 has a stopper 256 for retaining the shaft 255 and an upper surface of the stopper 256. The arranged O-ring 257 is attached.

An opening 201 is formed in the upper surface 203 of the fuel storage tank 20 at a position corresponding to the O-ring 257. Further, a coil spring 259 urged in a direction to push up the diaphragm 252 is provided between the upper surface 203 and the plate 254 of the diaphragm valve 25.

A ventilation hole 258 is formed on the lower surface side of the diaphragm 252, that is, between the upper surface 203 of the fuel storage tank 20 and the supporter 13, and communicates with the empty space (above the liquid level) of the sub tank 12. The space of the sub-tank 12 communicates with the space of the fuel tank 11 through an opening 123 provided at the top as shown in FIG. On the other hand, the bottom 202 of the fuel storage tank 20 opens below the liquid level of the fuel storage 121.

The bottom of the sub-tank 12 is a two-stage bottom at the top and bottom, an opening 125 is opened in the upper bottom, and the check valve 41 is mounted. The check valve 41 is slightly above the suction port 173 of the fuel pump 17.

ジ ェ ッ ト A jet pump constituting the fuel suction mechanism 30 is provided on the bottom of the sub tank 12 on the side opposite to the check valve 41. The jet pump has a jet nozzle 301 drilled below the return pipe 45 and a suction pipe 303 having a suction port 302 facing the jet nozzle 301.

The jet pump injects the fuel 8 returned from the return tube 442 from the jet nozzle 301, sucks up the fuel 8 in the fuel tank 11 from the suction port 302, and discharges the fuel 8 into the sub tank 12 from the discharge port 304.

Next, the operation and effect of the fuel supply device 10 of the present embodiment will be described. When the fuel is supplied to the fuel tank 11, the check valve 41 is opened, the fuel is introduced into the sub tank 12, and the fuel pump 17 can discharge the fuel. When the motor 176 of the fuel pump 17 is operated, the fuel is discharged from the discharge port 171 and the fuel is supplied from the main tube 441 to an engine (not shown).

The surplus fuel of the engine is returned from the return tube 442 to the sub-tank 12 as return (return) fuel, and is injected from the jet nozzle 301 of the return pipe 45. As a result, the fuel in the fuel tank 11 is pumped from the suction pipe 303 to the sub-tank 12, and the liquid level in the sub-tank 12 rises.

On the other hand, at the same time as the operation of the fuel pump 17, the pressure of the branch pipe 136 increases to a predetermined value (about 2.55 to 3.0 kgf / cm2), and the diaphragm 252 of the diaphragm valve 25 shown in FIG. Press down. As a result, the O-ring 257 opens the opening 201 on the upper part of the fuel storage tank 20, the empty part of the fuel storage tank 20 communicates with the empty part of the sub tank 12, and the liquid level of the fuel storage tank 20 becomes It matches the liquid level.

On the other hand, the fuel 8 in the fuel tank 11 is pumped up by the fuel suction mechanism 30 together with the operation of the fuel pump 17, and the liquid level in the sub tank 12 rises, and at the same time, the liquid level in the fuel storage tank 20 rises. As a result, the fuel eventually overflows from the upper part of the sub tank 12. Therefore, even when the fuel in the fuel tank 11 is low, the liquid level in the sub-tank 12 is kept high, and the operation can be performed until the fuel in the sub-tank 12 is almost exhausted.

On the other hand, when the operation is stopped and the fuel pump 17 is stopped, the fuel pressure in the branch pipe 136 also decreases to near the atmospheric pressure, and the operation of the diaphragm valve 25 is restored. That is, the O-ring 257 closes the opening 201 on the upper surface of the fuel storage tank 20 by the urging force of the coil spring 259 shown in FIG. Then, the upper surface 203 of the fuel storage tank 20 is closed, and the fuel level in the fuel storage tank 20 is maintained in that state.

As a result, even in a state where a large amount of fuel in the fuel tank or sub-tank has been lost due to parking for a long time or the like, fuel is secured and remains in the fuel storage tank 20 of this example. Then, when the fuel pump 17 is started, the pressure of the branch pipe 136 rises, the fuel tank valve 25 is operated, and the opening 201 of the fuel storage tank 20 communicates with the atmosphere (the space of the sub tank). As a result, the liquid level in the fuel storage tank 20 is lowered to discharge the fuel into the sub-tank, and the engine can be started.

As described above, according to the present embodiment, it is possible to provide the fuel supply device 10 which does not lose fuel from the fuel storage tank even after parking for a long time, reliably supplies fuel to the engine, and can start the vehicle. Can be.

(Reference Example 2)
As shown in FIG. 3, this embodiment is a fuel supply device 10 of a returnless system in which fuel return from an engine is not provided in Reference Example 1. The jet pump is driven by the branch fluid energy of the discharged fuel. That is, in this example, as shown in FIG. 4, the branch pipe 137 is provided in the pressure chamber 263 of the diaphragm valve 26. Then, as shown in FIG. 3, a part of the discharge fuel branched from the discharge pipe 172 flows through the branch pipe 137 to drive the jet pump of the fuel suction mechanism 30. The provision of the branch pipe 137 also functions as a regulator of the discharge fuel pressure.

The branch pipe 137 is attached to the cover 261 of the diaphragm valve 26, as shown in FIG. 4, and connects the pressure chamber 263 and the return pipe 45 of the fuel suction mechanism 30 (FIG. 3). A part of the fuel discharged from the fuel pump 17 flows from the branch pipe 136 to the branch pipe 137 via the pressure chamber 263 of the diaphragm valve 26. Next, the fuel flows into the return pipe 45 of the fuel suction mechanism 30 shown in FIG. 3 and is jetted from the jet nozzle 301, and the fuel in the fuel tank 11 is pumped from the suction pipe 303 to the sub tank 14 by the jet energy.

In order to adopt such a configuration, the fuel suction mechanism 30 is adjacent to the fuel storage tank 20, and the check valve 41 and the opening 125 are adjacent to the fuel pump 17. Further, a return tube (reference numeral 442, reference example 1) is not required for the flange 440. The supporter 130 has an upper opening 123 that communicates the space of the sub tank 120 with the space of the fuel tank 11. Others are the same as in Reference Example 1.

(Example 1)
In this embodiment, as shown in FIG. 5, the fuel pump 31 serving as the fuel suction mechanism 31 is driven by using the fuel ejected from the air holes 180 (FIG. 6) of the turbine fuel pump 18 in the first embodiment. This is an example of the present invention. The turbine type fuel pump 18 has advantages of low noise and low pulsation as compared with a positive displacement pump, and has been frequently used in recent years. On the other hand, since the turbine type fuel pump 18 has no self-priming force, an air hole for priming water (conventionally 0.9 to 1.0 φ) is required.

燃料 Fuel is constantly discharged from this air hole while the fuel pump 18 is operating. In this embodiment, the shape of the air hole 180 is changed to a fuel passage, a nozzle (metal nozzle 182) is formed at an end, and a jet pump is driven.

That is, as shown in FIG. 6, a vapor passage 181 communicating with the air hole 180 is provided below the fuel pump 18, and a metal nozzle 182 is press-fitted into the lower end thereof and fixed. Then, a throat 311 constituting a jet pump as the fuel suction mechanism 31 is disposed at a position facing the metal nozzle 182. The throat 311 has an inner diameter of about 6 to 7 mm.

(4) When fuel is ejected from the metal nozzle 182, the fuel is sucked into the throat 311 from the suction pipe 312 of the jet pump. The fuel outlet 313 of the throat 311 is opened above the fuel storage 151 of the sub tank 15 as shown in FIG.

ド ー A donut-shaped cushion 183 is interposed between the bottom of the fuel pump 18 and the bottom of the sub-tank 15. A check valve 42 is provided below the suction pipe 312. On the other hand, a filter 138 for receiving return fuel is provided on the upper surface of the supporter 140 directly below the return tube 442 of the flange 47.

The joint 141 of the supporter 140 with the fuel pump 18 is connected to the main tube 441 via a sliding seal 142 at an upper portion thereof, and a residual pressure holding valve 135 is attached at a lower portion thereof.

Next, the operation and effect of this example will be described. In recent years, there has been an increasing need to reduce the return fuel from the engine to the fuel supply, thereby reducing heat loss from the engine and reducing fuel evaporation. In the method of using the return fuel for fuel suction, when the fuel consumption in the engine increases, a phenomenon occurs in which the return fuel decreases and the power of the fuel suction mechanism decreases.

燃料 Since the fuel supply device of this example is not a fuel suction mechanism using the fluid energy of the return fuel, the above-mentioned concerns are unnecessary. That is, as long as the discharge pressure of the fuel is constant, a constant fuel suction capacity can be expected.

In this example, energy of 25 to 25 liters / Hr can be obtained at 0.8 to 1.0 kgf / cm2 with respect to the fuel discharge pressure of the fuel pump 18 of 2.55 to 3 kgf / cm2, and the engine consumption flow rate increases. Even if the liquid level in the sub tank is increased by about 150 mm, it is sufficiently possible. Further, since the fuel is not heated unlike the return fuel, there is no need to worry about the vapor lock resistance due to the reduced pressure boiling.

Furthermore, there is an advantage that a system without return fuel can be supported. In this example, the residual pressure holding valve 135 is provided on the fuel pump 18 side of the branch pipe 136. Therefore, when the fuel pump 18 is stopped, the pressure applied to the diaphragm valve 25 is higher than in the first and second embodiments, and the diaphragm valve 25 operates with this small pressure difference.

That is, the pressure (2.8 kgf / cm2 or 2.35 kgf / cm2 in the above example) is lower than the system pressure (eg, 3 kgf / cm2 or 2.55 kgf / cm2) when the fuel pump 18 is operated by about 0.2 kgf / cm2. Thus, the fuel tank valve 25 operates to close. Others are the same as in Reference Example 1.

(Example 2)
This embodiment is another embodiment in which the residual pressure holding valve 135 is provided downstream of the branch pipe 136 as in the first embodiment, as shown in FIG. That is, the residual pressure holding valve 135 is mounted downstream of the joint 151 of the supporter 150. Therefore, the operating pressure of the fuel tank valve 25 is the same as in the first embodiment. Others are the same as in the first embodiment.

(Example 3)
In this embodiment, as shown in FIG. 8, another embodiment in which a branch pipe 137 is provided in the diaphragm valve 26 in the first embodiment to perform the function of the regulator and the return tube (reference numeral 442 in FIG. 5) is eliminated. It is an example. That is, as shown in FIG. 8, a return pipe 450 is connected to the pressure chamber 263 (FIG. 4) of the diaphragm valve 26, and this return pipe 450 communicates with the inside of the sub tank 16. Then, the function of the regulator of the discharged fuel is performed.

か ら Since the flange 48 has no return tube, the supporter 160 does not require a filter (reference numeral 138 in FIG. 3). Further, the check valve 41 is not provided below the suction pipe 312 of the jet pump, but is provided at the bottom of the sub tank 16 as in the first and second embodiments.

As a result, the pressure loss of the check valve 41 in the suction pipe 312 is eliminated, and the suction power of the jet pump of the fuel suction mechanism 31 increases. Therefore, the discharge port 314 of the throat 310 of the jet pump can be provided at the upper part, and the liquid level of the sub tank 15 can be raised as compared with the first embodiment. Others are the same as in the first embodiment.

FIG. 4 is a cross-sectional view of the fuel supply device of Reference Example 1. FIG. 4 is an enlarged view around the diaphragm valve of Reference Example 1. Sectional drawing of the fuel supply device of the reference example 2. FIG. 9 is an enlarged view of the periphery of the diaphragm valve of Reference Example 2. FIG. 2 is a cross-sectional view of the fuel supply device according to the first embodiment. FIG. 2 is an enlarged view around the jet pump according to the first embodiment. FIG. 10 is a cross-sectional view of the fuel supply device according to the second embodiment. FIG. 10 is a sectional view of a fuel supply device according to a third embodiment.

Explanation of reference numerals

10. . . Fuel supply device,
11. . . Fuel tank 15. . . Sub tank,
18. . . Turbine fuel pump,
31. . . Fuel suction mechanism,
180. . . Air holes,
181. . . Vapor passage,
182. . . Metal nozzle,
311. . . Throat,

Claims (2)

A turbine type fuel pump disposed in the fuel tank and for pumping fuel to a fuel consuming device outside the fuel tank;
A sub-tank that houses the turbine-type fuel pump and stores fuel introduced into the fuel pump by introducing the fuel from the fuel tank;
A jet pump for pumping fuel in the fuel tank into the sub-tank,
The jet pump has a vapor passage communicating with an air hole of the turbine fuel pump, a nozzle provided at an end of the vapor passage, and a throat provided at a position facing the nozzle, and the air hole A fuel supply device driven by using fuel ejected from the fuel supply device. The fuel supply device according to claim 1, wherein the nozzle and the throat are arranged horizontally.