JPH02211373A - Fuel pump - Google Patents

Abstract

PURPOSE:To improve the high temperature restarting performance of an engine by exceedingly suppressing the idle pumping-up of a fuel pump and the generation of vapor in other fuel system by installing a storing body for securing the fuel containing the less quantity of the component having a low boiling point. CONSTITUTION:A filter 4 supported by a skeleton member 3 is installed into a suction pipe 6, and also a storing body 2 which surrounds the periphery of the filter 4 is supported by the skelton member 3. The filter 4 is constituted of a filter film 4a having fine holes as filter sieve for removing the solid substance in fuel. The storing body 2 is constituted of a storing body film 2a having the fine holes having the larger diameter than that of the filter film 4a. The excessive fuel is returned into a subtank 3 from a return pipe 32. The evaporation of the component having a low boiling point in the excessive fuel is proceeded by the engine temperature, and the fuel containing less quantity of the component having a low boiling point is formed. During the engine operation, the fuel containing less quantity of the component having a low boiling point flows into the subtank 36 from the return pipe 32.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to improving the high-temperature restartability of a vehicle internal combustion engine (hereinafter also referred to as an engine) (when restarting the engine after a while after the engine has stopped operating). Regarding the improvement of fuel pumps to improve starting conditions (when the atmosphere in the fuel system is high temperature), in particular, fuel pumps with fewer low boiling point components inflow compared to the fuel in the main fuel tank (hereinafter referred to as main tank) This invention relates to improvements to filters for fuel pumps installed in fuel sub-tanks (hereinafter also referred to as sub-tanks).

[Prior Art] A conventional technology will be explained with reference to FIGS. 6 and 7.

FIG. 6 is a schematic diagram showing a conventional example. Figure 7 is the 6th
It is a sectional view taken along the line CC in the figure, showing the positional relationship of each part H. In the figure, 34 is the main tank. The main tank 34 is connected to the main tank 3 through a communication port 36a.
A subtank 36 is provided which communicates with the fuel tank 4, and both tanks are filled with fuel through a communication port 36aI%-.

Note that F in the figure indicates fuel. A fuel pump 1 that discharges and supplies fuel to the engine side is disposed within the sub-tank 36 and supported by a bracket (not shown). A filter 4 for removing solid matter from the fuel is attached to a suction port located at the bottom of the fuel pump 1 in the drawing. On the other hand, fuel pump 1
A discharge pipe 30 is connected to the upper part of the fuel pump 1 in the figure, and the fuel discharged by the fuel pump 1 is supplied to the engine side through this pipe. A return pipe 32 is led into the sub-tank 36, and surplus fuel from the engine is transferred to the sub-tank 36.
It is meant to be brought back inside.

According to the above configuration, the sub-tank 36 is used when the vehicle turns, etc.
This prevents the fuel from being drawn to one side of the tank and becoming unable to be discharged. Furthermore, since the fuel pump 1 is in operation while the engine is operating, surplus fuel is supplied from the engine side through the return pipe 32 into the sub-tank 36. This fuel is passing through a high temperature atmosphere on the engine side, so it is quite high temperature.
Volatilization of low-boiling components in the fuel has progressed, resulting in a composition with less low-boiling components. Therefore, fuel containing few low-boiling point components is stored in the sub-tank 36.

As a result, fuel outside the sub-tank 36 is transferred to the communication port 36.
Even if the fuel in the sub-tank 36 mixes with the fuel to some extent through a, the fuel pump 1 sucks in fuel with fewer low-boiling point components than usual. Since the generation of vapor due to boiling point components is suppressed, emptying of the fuel cylinder 11 is prevented, and a decrease in the discharge flow rate can also be suppressed (see, for example, Japanese Utility Model Application No. 54-92214, etc.).

[Problems to be Solved by the Invention] However, the conventional fuel pump 1 described above cannot sufficiently cope with the restart of the engine at a high temperature. This is because when the engine is stopped, the high temperature surplus fuel no longer flows into the sub tank 36 from the return pipe 32.

On the other hand, since the fuel in the main tank 34 is exposed to a high-temperature atmosphere, many low-boiling components remain. Therefore, as time passes, the fuel inside and outside the sub-tank 36 diffuses and mixes, causing the sub-tank 36 to
6, the low boiling point components of the fuel gradually increase.

Therefore, when starting the engine in such conditions,
Fuel containing a large amount of low boiling point components is sucked in by the fuel pump 1, and the fuel tends to vaporize near the suction port, resulting in a decrease in the discharge amount due to emptying of the fuel pump 1, or the generation of vapor in other fuel systems. As a result, the air-fuel ratio of the engine becomes over-lean, which hinders starting and becomes a problem.

Therefore, in order to solve the above problems, the present invention stores fuel with a small amount of low boiling point components so that the fuel with a small amount of low boiling point components is sucked into the fuel pump. The problem to be solved is to provide a fuel pump that can perform a good start when restarting at a high temperature.

[Means to solve the problem] The above problem is solved by the following means.

That is, the fuel tank is installed in a fuel sub-tank into which a fuel with less low boiling point components than the fuel in the main fuel tank flows and communicates with the main fuel tank, and sucks the fuel from the suction port into the main fuel tank. A fuel pump that discharges and supplies fuel to the outside, which has a filter that filters fuel and guides it to the suction port, and a storage body that surrounds and wraps the filtration surface of the filter and can store the fuel that has few low boiling point components. Solved by pump.

[Work] Next, the operation of the present invention will be explained.

According to the above configuration, since fuel containing few low boiling point components is stored in the reservoir, there is little vapor generation in the reservoir and the fuel pump even when the engine is restarted at a high temperature. In addition, it is possible to prevent the fuel from becoming vapor particularly near the suction port of the fuel pump and causing the fuel pump to become empty, or from generating vapor in other fuel systems.

Furthermore, once the engine is started, the fuel system is already pressurized, so vapor generation can be suppressed even if millet containing many low-boiling components is supplied from outside the reservoir. . That is, by ensuring that the fuel sucked into the reservoir at the start of the pumping action is low in low-boiling point components, it is possible to perform the startup and subsequent operations without any trouble.

[Example] Give an explanation.

FIG. 1 is a schematic vertical sectional view of this embodiment. In the figure, 1 is a fuel pump. The fuel pump 1 is installed in the main tank 34 in the manner shown in FIGS. 6 and 7 described above.

The fuel pump 1 has a pump section formed on the lower side in the drawing.

That is, the impeller 10 is attached to the lower end of the motor shaft 12 in the drawing and is rotatable within the pump chamber surrounded by the pump cover 15, the pump body 13, and the like. A suction port 8 is opened in the pump body 13 to introduce fuel into the pump chamber. A suction pipe 6 is attached to the suction port 8 . The suction pipe 6 has a suction port 6a opening toward the bottom of the main tank 34 so as to minimize the amount of ineffective fuel remaining in the main tank 34 as much as possible. A filter 4 supported by aggregate 3 is installed in the suction pipe 6.
is provided, and the reservoir 2 roughly surrounding the filter 4 is also supported by the aggregate 3 (see A- in FIG. 1).
(See also FIG. 2, which is a cross-sectional view along line A). The filter 4 is composed of a filter membrane 4a having pores serving as sieves for eliminating solid matter in the fuel. The reservoir 2 is composed of a reservoir membrane 2a having pores with a larger diameter than the filter membrane 4a. Note that the size of the pores of the reservoir membrane 2a may be substantially the same as that of the filter membrane 4a.

A motor section of the fuel pump 1 is formed within a motor housing 14. A core 16 in which thin ferromagnetic plates are laminated is fixed to a motor shaft 12 that passes through the center of the motor housing 14 . A coil 20 that excites the core 16 is wound around the core 16 so that magnetic flux is generated. On the other hand, a permanent magnet stator 18 is fixed to the motor housing 14 . A commutator 22 is fixed to the upper end of the motor shaft 12 in the drawing. A brush 24 is in contact with the commutator 22. The brush 24 is housed in a holder 25 fixed to the motor housing 14. Further, the brush 24 is electrically connected to a power terminal 26 attached to the cover 29. cover 2
9 is provided with a discharge port 28 which is a fuel outlet.

The discharge port 28 is connected to a discharge pipe 30 for supplying fuel to an engine (not shown) (see FIG. 6).

Note that the impeller 10 does not need to be driven by a brushed DC motor as in this embodiment. Further, the position of the return pipe 32 is not limited to the position shown in FIGS. 6 and 7, but may be placed closer to the filter 4.

Next, the functions and effects of this embodiment will be described.

When the engine is running, the fuel pump 1 is energized, the motor shaft 12 rotates, and the impeller 10 in the pump chamber rotates. As the impeller 10 rotates, the fuel sucked into the pump chamber from the suction port 8 is pressurized.
A discharge port 28 passes through a fuel passage within the motor housing 14.
It is supplied to the engine side via the discharge pipe 30.

On the other hand, surplus fuel is returned to the sub tank 36 from the return pipe 32. At this time, the surplus fuel has a low boiling point component content as the low boiling point components in the fuel are evaporated due to the temperature of the engine. When the engine is in operation, fuel containing few low-boiling components flows into the sub-tank 36 from the return pipe 32. Therefore, the storage body 2 is always filled with fuel containing few low boiling point components during engine operation. Further, even immediately after the engine is stopped, fuel with a small amount of low boiling point components is secured in the storage body 2.

Therefore, even when the engine is restarted at a high temperature after the engine is stopped, the fuel containing less low boiling point components in the storage body 2 is sucked into the fuel pump 1. This suppresses the generation of vapor in the reservoir 2, which not only prevents the fuel pump 1 from becoming empty, but also suppresses the amount of vapor generated in other fuel systems. In this way, the required amount of fuel can be supplied to the engine, so that the engine can be restarted at a high temperature.

Note that, since the storage body 2 is a type of filter, it may be considered to eliminate the filter 4 located inside. In other words, this corresponds to a filter that is larger than the conventional one. According to this type, if the fuel in the reservoir 2 is sucked in and then the fuel outside the reservoir 2 is sucked in, the same effect as in this embodiment can be obtained. However, in reality, fuel from outside the reservoir 2 is quickly sucked into the portion near the suction port 6a, and the original effect of the reservoir 2 cannot be obtained. On the other hand, as in this embodiment, the filter 4
By covering the reservoir body 2 with the reservoir body 2, not only the fuel in the filter 4 is not sucked in, but also the fuel from outside the reservoir body 2 is prevented from being sucked in.

Further, the surface area of the reservoir membrane 2a of the reservoir 2 is the same as that of the filter membrane 4.
Since the pore size of the reservoir membrane 2a is approximately equal to or larger than the pore size of the filter membrane 4a, solid matter outside the filter 4 can be captured. Thereby, clogging of the filter 4 can be prevented, and an increase in the suction resistance of fuel by the fuel pump 1 can be prevented.

Further, even though this embodiment is a kind of double filter, the loss is suppressed to a practically negligible level.

In addition, in this embodiment, an improvement in high-temperature restartability can be expected with a simple change of replacing the filter attached to a conventional fuel pump with a filter 4 surrounded by a reservoir 2, thereby reducing costs. effective.

Furthermore, since the amount of fuel held by the storage body is increased compared to the conventional one, it is possible to obtain effects such as preventing malfunctions caused by running out of fuel when the vehicle turns or runs on an incline.

Note that the entire reservoir 2 does not need to be formed of a material having pores, and a portion thereof may be formed of a membrane without pores.

<Second Embodiment> Next, a second embodiment according to the present invention will be described based on the drawings. FIG. 3 shows an example in which an opening 40 that communicates the inside and outside of the reservoir 102 is provided in the upper surface 102a of the reservoir 102 at a position away from the suction port 6a. The size of the opening 40 is larger than the pores of the reservoir membrane 102a, and the pores are small enough to prevent the fuel inside and outside the reservoir 102 from easily mixing in a short period of time. By providing the opening 40, vapor generated inside the storage body 102 can be discharged to the outside. This prevents vapor from entering the fuel pump 1 when the engine is restarted at a high temperature, and the amount stored in the storage body 102 can be effectively utilized. In this way, high temperature restartability can be improved.

Third Embodiment> Next, FIGS. 4 and 5 will be explained about the third embodiment of the present invention.
Explain based on the diagram. FIG. 4 shows an arrangement in which the reservoir 2 in the first embodiment is replaced with a reservoir 202.

FIG. 5 shows a cross section taken along line BB in FIG. 4. However, in FIG. 5, the reservoir 2
It is a sectional view when 02 is bottomed out.

The storage body 202 is provided with an elastic material 50 in addition to the aggregate 3 as a member for supporting it. The elastic member 4450 supports the storage body 111202a by expanding it from the inside. As a result, the volume of the storage body 202 can be further increased, so that a large amount of fuel containing low boiling point components can be secured after the engine is stopped. Further, since the elastic material 50 is used, it effectively acts against vibrations of the fuel pump 1, the main tank 34, etc., and noise etc. are prevented.

[Effects of the Invention] As described above, according to the present invention, by using a storage body that secures fuel with a small amount of low boiling point components, when the fuel pump is empty, vapor generation in other fuel systems can be suppressed as much as possible. Therefore, the high temperature restartability of the engine is improved.

[Brief explanation of the drawing]

Embodiments according to the present invention are shown in FIGS. 1 to 5, FIG. 1 is a vertical sectional view of the main part of the first embodiment, and FIG. 2 is a Δ
-A sectional view, FIG. 3 is a longitudinal sectional view of the main part of the second embodiment, FIG. 4 is a longitudinal sectional view of the main part of the third embodiment, and FIG. 5 is a sectional view taken along the line B-B in FIG. 4. It is. The conventional example is shown in FIGS. 6 and 7, where FIG. 6 is a schematic diagram of the conventional example, and FIG. 7 is a sectional view taken along the line CC in FIG. 6. 1...Fuel pump 2.102.202...Reservoir 4...Filter 6...Suction pipe, 5a...Suction port 34...Main tank 36...Sub tank 40...Opening Part 50...Elastic material

Claims (1)

[Scope of Claims] The fuel sub-tank is installed in a fuel sub-tank into which a fuel having a lower boiling point component than the fuel in the fuel main tank flows and communicates with the fuel main tank, and the fuel is sucked from the suction port to A fuel pump that discharges and supplies fuel to the outside of a tank, comprising a filter that filters fuel and guides it to the suction port, and a storage body that surrounds and wraps the filtration surface of the filter and can store the fuel that has few low boiling point components. Fuel pump.