JPH022940Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to a fuel suction mechanism for a fuel pump that pumps fuel such as gasoline or diesel oil from a fuel tank mounted on a vehicle such as an automobile. This invention relates to a fuel suction mechanism for a fuel pump.

(Prior art) In this type of mechanism, the fuel suction pipe that is connected to the fuel pump and extends into the fuel liquid in the fuel tank is formed of a circular pipe. In order to minimize the amount of inactive fuel remaining in the fuel tank, the opening is located close to the lowest bottom of the fuel tank, and when driving on a slope, for example, the parallelism between the bottom of the fuel tank and the fuel liquid level is lost and the fuel is removed. It is desirable to open at a position where the liquid level changes the least (hereinafter referred to as the position of minimum liquid level fluctuation), considering that the liquid level may be biased towards the front or rear in the fuel tank. For this reason, normally, the fuel suction pipe is extended downward from the fuel pump connection part to near the bottom of the fuel tank, and then bent from there until it reaches the above-mentioned minimum level fluctuation position almost parallel to the bottom of the fuel tank. A configuration in which the suction port is opened is adopted.

(Problem to be solved by the invention) In the above configuration, in order to reduce the remaining amount of inactive fuel in the fuel tank, that is, to increase the effective capacity, the suction port of the extending pipe portion of the fuel suction pipe is approximately parallel to the bottom surface of the fuel tank. It is possible to open the pipe as close to the bottom of the fuel tank as possible, but if it is opened too close, the extending pipe may come into contact with the bottom of the fuel tank and scratch it, causing the plating to peel off and cause corrosion. Therefore, there is a limit to the reduction in the remaining amount of ineffective fuel by bringing the extension pipe closer to the bottom of the fuel tank.

Therefore, in order to further reduce the remaining amount of ineffective fuel, it is possible to reduce the diameter of the extension pipe and lower the position of its suction port, but in this case, the required amount of fuel to be taken out is There was a drawback that it could not be secured.

Furthermore, in the above-mentioned turbine-type fuel pump, due to the pulsation of the fuel at the outlet of the flow path inside the pump, the vertical axis changes at a frequency (KHz) determined by the number of impeller blades x impeller rotation speed, as shown in Figure 3. Generates sound with the sound pressure (dB(A)) shown in . This sound is called the first-order sound of the impeller, and the first-order sound of the impeller is transmitted from the main body of the fuel pump to the fuel suction pipe, or reversely follows the flow path inside the pump and enters the fuel suction pipe. It is known that the amplitude increases due to the so-called "blowing" phenomenon, which increases the amplitude due to reflection within the extending pipe section. Furthermore, the frequency range of automobile fuel pumps is generally approximately 2
~6KHz, and the primary frequency P in the figure (approximately 3.8KHz)
The sound pressure becomes particularly high and is amplified by the blow-up phenomenon, producing a harsh, harsh sound.

Such a blow-out phenomenon occurs when the cross-sectional shape of the flow path of the extending pipe section is circular, that is, the aspect ratio is set to 1/1, as in the conventional technology described above, due to the relationship with the required cross-sectional area of the flow path, etc. The resonant frequency was almost equal to the frequency of the first-order sound of the impeller, resulting in particularly loud noise.

(Means for Solving the Problems) In view of the drawbacks of the prior art described above, the fuel suction mechanism of the fuel pump of the present invention has a substantially horizontal direction with a suction port extending from the tip of the fuel tank mounted on a vehicle such as an automobile. A fuel suction mechanism for a turbine-type fuel pump that pumps fuel through a fuel suction pipe having an extending pipe portion, wherein the cross-sectional shape of the flow path inside the extending pipe portion of the fuel suction pipe is The aspect ratio is set to be 1/3 to 1/6.

(Function) In the fuel suction mechanism of the present invention, the cross-sectional shape of the flow path inside the extending pipe section is set so that its aspect ratio is 1/3 to 1/6, so the cross-sectional shape of the flow path becomes horizontally long. , the distance between the lower surface of the extending pipe section and the bottom of the fuel tank is maintained at an appropriate distance that does not cause mutual contact, and the cross-sectional area of the flow path is maintained at a predetermined value depending on the discharge amount of the fuel pump. In this state, the height of the dead fuel defined by the upper surface of the flow path of the extending pipe portion can be reduced. In addition, by setting the aspect ratio to 1/3 to 1/6, the resonant frequency of the extending pipe section is shifted from the frequency of the impeller's own sound, which causes the impeller's primary sound to be transmitted to the extending pipe section. Increase due to blow-up phenomenon is controlled.

(Example) Next, an example of this invention will be described with reference to the drawings.

In Fig. 1, reference numeral 1 denotes a substantially cylindrical turbine-type fuel pump, which is installed inside the main tank T (only the bottom plate Ta is shown in the figure) via a bracket 2. It is fixed to the ceiling wall (not shown) of T. Here, the central axis of the fuel pump 1 is substantially perpendicular to the bottom plate Ta of the main tank T, and the bottom half of the fuel pump 1 is substantially perpendicular to the bottom plate Ta of the main tank T.
The tank Sa projects into a sub-tank S with an opening at the top. Note that the side wall Sb of the sub-tank S is provided with a passage (not shown) that communicates with the main tank T, and the liquid level L of the fuel F when the vehicle is stopped on level ground is equal to the bottom wall of the sub-tank S.
It is almost parallel to Sa, that is, it is almost parallel to the bottom plate Ta of the main tank T. Reference numeral 3 denotes a fuel supply pipe whose one end is connected to the discharge port 1a at the upper part of the fuel pump 1, and the other end is connected to a fuel injection nozzle (not shown) or the like. 4 and 5 are external wiring connection terminals for supplying electricity to the fuel pump 1. 6 has one end connected to the intake port 1b at the lower part of the fuel pump 1, and is connected to the fuel F in the sub tank S, that is, the main tank T.
It is a fuel suction pipe for sucking in fuel, and its suction port 6
A cylindrical fuel filter 7 is attached to cover a, and the structure thereof will be explained in more detail below.

The fuel suction pipe 6 is the suction port 1b of the fuel pump 1
A cylindrical connecting pipe portion 6A constituting a connecting portion with the
The connecting pipe portion 6A is bent at a substantially right angle from the lower end thereof and extends parallel to the bottom wall Sa of the sub-tank S, that is, parallel to the lower bottom plate Ta of the main tank T.
Extended pipe section 6 consisting of a rectangular square tube with a horizontally long cross section
It has B. Here, the height H1 of the lower bottom surface of the extension pipe portion 6B is set to the smallest dimension that can prevent contact with the bottom wall Sa of the sub-tank S, and the suction port 6a at the end is It opens with minimum positional fluctuation. On the other hand, the fuel filter 7 is attached so as to cover the extending pipe part 6B so that the suction port 6a is located at the lower bottom in the substantially central part of the fuel filter 7, and the central axis thereof is parallel to the extending pipe part 6B. Further, the end plate 7a of the fuel filter 7 on the side closer to the fuel pump 1 is formed integrally with the extending pipe portion 6B as shown in FIG.

Furthermore, to explain the shape of the flow path C inside the extending pipe portion 6B of the fuel suction pipe 6, in FIG. :6, and the flow path area is set to a value sufficient to ensure the required amount of fuel taken out by the fuel pump 1. In addition, H2 in FIG. 1 indicates the height from the bottom wall Sa of the sub-tank S to the top surface of the flow path C.
Fuel F below this height cannot be pumped out by the fuel pump 1 and remains.

Next, the effects of the above embodiment will be explained. When the fuel pump 1 is energized via the external wiring connection terminals 4 and 5, the fuel F in the sub-tank S, that is, the main tank T, is filtered by the fuel filter 7 and then sucked into the fuel pump 1 via the fuel suction pipe 6. The fuel is further supplied to a fuel injection nozzle (not shown) through the fuel supply pipe 3. As fuel F is supplied in this way, the fuel level L in the sub-tank S also gradually falls, but when the liquid level reaches the height H2, the liquid level L and the bottom plate of the main tank T drop. When Ta is parallel, it becomes impossible for the fuel pump 1 to suck in the fuel F, and the height H2
The following fuel F remains as invalid fuel. Here, since the extending pipe portion 6B of the fuel suction pipe 6 has a horizontally long rectangular shape, the upper surface position of the flow path C is lowered at the same flow area compared to when the fuel suction pipe is made into a normal cylindrical shape. can be set, and therefore the remaining amount of ineffective fuel can be reduced.

Furthermore, by setting the ratio of the height dimension e to the width dimension f of the channel C to 1:3 to 1:6, noise generation can be reduced even if the channels have the same cross-sectional area. To explain this effect in relation to the increase in the impeller's primary sound due to the blowout phenomenon in the extension pipe section, which was explained in the section "Problems to be solved by the invention," FIG. Changes in the sound pressure of the sound generated in the extension pipe section 6 of the fuel pump 1, which generates the impeller primary sound of the frequency indicated by P in the figure, are shown in relation to changes in e/f. 〇 indicates that the cross-sectional area of channel C is 100 mm ² , × indicates that the cross-sectional area of channel C is 200 mm ²
This is the plot for the case. As shown in the figure, by setting e/f in the range of 1/3 to 1/6, the resonant frequency deviates from the frequency of the impeller's primary sound, thereby suppressing the blowing phenomenon and achieving a remarkable noise reduction effect. be able to. Note that e/f=1 corresponds to the case of a conventional fuel suction mechanism having a cylindrical extending pipe portion. In addition, although this noise reduction effect is shown only for the frequency P (approximately 3.8 KHz) where the sound pressure is particularly high in the figure, noise reduction by setting e/f in the range of 1/3 to 1/6 The effect is obtained in the range of approximately 2 to 6 kHz, which is the frequency of the primary sound of the impeller of a general automobile fuel pump.

That is, in the fuel suction mechanism of this embodiment, the cross-sectional shape of the flow path C of the extending pipe portion 6 is set to e/f=1/3 to 1/6.
By setting it to , the increase due to the blowing phenomenon of the primary impeller is suppressed, and noise reduction can be achieved.

In addition, in the above embodiment, the extension pipe part of the fuel suction pipe was a rectangular square tube with a horizontally long cross section.
The cross-sectional shape is not limited to a square, but may be any shape as long as it has a long axis, such as an oval.

(Effects) As described above, in the fuel suction mechanism of a turbine-type fuel pump, the cross-sectional shape of the flow path inside the extending pipe portion of the fuel suction pipe has an aspect ratio of 1/3 to 1. /6, the distance between the lower surface of the extending pipe and the bottom of the fuel tank and the cross-sectional area of the flow path are maintained at predetermined values, and the distance defined by the upper surface of the flow path of the extending pipe is maintained at predetermined values. Since the height of the idle fuel that is generated can be lowered, the remaining amount of idle fuel in the fuel tank can be reduced, that is, the effective capacity can be increased.Furthermore, by setting the shape of the flow path as described above, fuel pump noise can be reduced. This has the effect of reducing the amount of water used.

[Brief explanation of the drawing]

The figures show one embodiment of this invention. Figure 1 is a partially sectional front view showing the fuel suction mechanism of the fuel pump, Figure 2 is a sectional view taken along the - line in Figure 1, and Figure 3 is a turbine. FIG. 4 is a characteristic diagram showing the relationship between the height and width ratio of the cross section of the extending pipe portion of the fuel suction pipe and the primary sound pressure of the impeller. 1...Fuel pump, 6...Fuel suction pipe, 6B...
Extension pipe section, 7...Fuel filter, T...Main tank, S...Sub tank, F...Fuel, C...Flow path.

Claims (1)

[Scope of utility model registration request] A fuel suction mechanism for a turbine-type fuel pump that pumps fuel from a fuel tank mounted on a vehicle such as an automobile through a fuel suction pipe having a substantially horizontally extending pipe section with a suction port at its tip. hand,
A fuel suction mechanism for a fuel pump, characterized in that a cross-sectional shape of a flow path inside the extending pipe portion of the fuel suction pipe is set such that an aspect ratio thereof is 1/3 to 1/6.