JPH0447412Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This school's proposal relates to a fuel injection device that is suitably used to supply fuel in a fuel tank to, for example, an automobile engine. and a sub-tank.

[Prior Art] Conventionally, fuel tanks for automobiles have been divided into a main tank and a sub-tank due to constraints on the structure of the vehicle body, requests for increased tank capacity, and the like.

Therefore, FIGS. 3 and 4 show a prior art fuel injection device equipped with this type of fuel tank.

In the figure, 1 is a fuel tank that accommodates fuel A, and the fuel tank 1 is provided with a bottom plate 2, a right side plate 3, a left side plate 4, a front plate (not shown), a rear plate 5, a fuel filler port 6A, and a pipe insertion port 6B. The fuel supply port 6A is covered by a cap 7, and the pipe insertion port 6B is normally closed by a cover plate 8. At the center of the bottom plate 2 of the fuel tank 1, a shaped part 2A for straddling the rear axle housing B is formed to protrude inside the fuel tank 1, and a right bottom plate part 2B and a left bottom plate part 2 of the shaped part 2A are formed.
By providing a step C, the fuel tank 1 is made up of an integrally formed deep-bottomed main tank 1A that accommodates a fuel pump 9, etc., which will be described later, and a shallow-bottomed sub-tank 1B.

Reference numeral 9 denotes a fuel pump that is located within the fuel tank 1 and is located on the side of the main tank 1A, and that pumps fuel A to a fuel injection valve 13, which will be described later.The fuel pump 9 has a pump part and a motor part in a casing. It is roughly composed of a pump body 9A, a filter 9C connected to the suction port 9B of the pump body 9A, and a discharge port 9D provided in the pump body 9A and equipped with a check valve for maintaining residual pressure inside. .

One end of 10 is the discharge port 9D of the fuel pump 9.
12 is a pressure regulator connected to the other end of the discharge pipe 10. The pressure regulator 12 is connected to a supply pipe 14 that supplies fuel to the fuel injection valves 13, 13, . . . and a control pressure pipe 16 that introduces positive or negative pressure generated in the intake manifold 15 as control pressure, By introducing the control pressure, the return flow rate of the fuel flow rate supplied from the fuel pump 9 that is returned to the fuel tank 1 via the return piping 17 (described later) is controlled, and the fuel pressure supplied to each fuel injection valve 13 is controlled. is controlled to a predetermined set pressure.

Reference numeral 17 denotes a return pipe for returning surplus oil of fuel A supplied from the fuel pump 9 to the fuel tank 1 side. One end side of the return pipe 17 is connected to the pressure regulator 12, and the other end side is connected to the fuel tank 1 side.
It extends to the main tank 1A side.

18 is an ejector located on the main tank 1A side and provided on the tip side of the return pipe 17 in order to suck the fuel A stored in the sub tank 1B of the fuel tank 1 and flow it into the main tank 1A side. The fuel suction pump 18 has a pump body 18A as shown in FIG.
An oil passage 18B that penetrates through the oil passage 18B and communicates with the return pipe 17, a large-diameter oil sump chamber 18C that is provided in the middle of the oil passage 18B, and an oil sump chamber 18C that is inserted into the oil sump chamber 18C from the lateral direction as shown in the figure. Communicating suction path 18D
It is made up of. And the fuel suction pump 1
The proximal end side of a suction pipe 19 is connected to the suction path 18D of No. 8, and the suction port on the distal end side 19A of the suction pipe 19 is located below the shaped portion 2A of the fuel tank 1 and is disposed within the sub-tank 1B. There is.

The prior art is configured as described above, and its operation will now be explained.

The fuel pump 9 is driven to supply fuel A in the fuel tank 1 to the fuel injection valve 13 side via the discharge pipe 10. At this time, the pressure regulator 12 introduces positive pressure or negative pressure from the intake manifold 15 as a control pressure, and controls the return flow rate of the fuel flow rate supplied from the fuel pump 9 to the fuel tank 1 side. The pressure of fuel supplied to the injection valve 13 is controlled to a predetermined set pressure.

Thus, the fuel injection valve 1 is activated by the fuel pump 9.
A part of the fuel A supplied to the fuel injection valve 1
3 into the fuel chamber of the internal combustion engine, and the remaining surplus oil is returned from the pressure regulator 12 to the fuel tank 1 via a return pipe 17.

In addition, as shown in FIG. 4, the fuel suction pump 18 provided at the tip side of the return pipe 17 allows excess oil from the return pipe 17 to flow through the oil passage 18B as a return flow in the direction of arrow C toward the nozzle port 18B ₁ side. , a negative pressure is generated in the oil reservoir chamber 18C, and this negative pressure sucks the fuel in the sub-tank 1B from the suction path 18D through the suction pipe 19 in the direction of arrow D. It is designed to sequentially send the excess oil to the main tank 1A side from the port _18B1 .

[The problem that the idea aims to solve]

By the way, in the above-mentioned conventional technology, a negative pressure is generated in the oil reservoir chamber 18C by using the return flow in the direction of arrow C flowing in the oil passage 18B of the fuel suction pump 18, and the fuel in the sub tank 1B is transferred to the main tank. 1A side, in order to increase the suction force due to the negative pressure, the nozzle port 18 of the oil passage 18B located below the oil reservoir chamber 18C.
B ₁ etc. are formed with a small diameter, and the return piping 17
When the foreign matter 20, etc. inside flows into the oil sump chamber 18C along with the return flow in the direction of arrow C as shown in FIG.
This foreign material 20 and the like may accumulate on the upper end side of the nozzle port 18B ₁ and block the nozzle port 18B ₁ .

For this reason, in the conventional technology, the return piping 17 may become clogged with the foreign matter 20 or the like in the nozzle port _18B1 .
It is no longer possible to return excess oil from the fuel tank 1 to the fuel tank 1, and the pressure in the return pipe 17 increases, making it difficult to adjust the fuel pressure by the pressure regulator 12, causing excessive pressure to act on each injection valve 13, etc. There are problems such as causing the engine to stall.

Furthermore, if a relief valve is provided in the oil passage 18B of the fuel suction pump 18 upstream of the oil reservoir chamber 18C, the pressure in the return pipe 17 can be relieved; however, simply providing a relief valve is sufficient. However, when the relief valve is opened, foreign matter 20 accumulates on the valve seat and the like, causing clogging on the relief valve side as well.

The present invention was developed in view of the problems of the prior art described above, and even if the fuel suction pump is clogged with foreign matter, it is possible to reduce the pressure in the return piping to a predetermined pressure or less, and each injection valve, etc. To provide a fuel injection device that can prevent excessive pressure from acting on the fuel.

[Means to solve the problem]

A feature of the configuration adopted by the present invention in order to solve the above-mentioned problems is that a foreign matter reservoir is located in the valve casing between the inlet and outlet of surplus oil in the middle of the return piping, and the above pressure is reduced. A relief valve is provided which relieves the pressure in the return pipe at a set pressure lower than that of the regulator.

[Effect]

The relief valve has a foreign matter reservoir located between the inlet and the outlet within the valve casing, so it is normally closed to allow excess oil from the return piping to flow from the inlet to the outlet. When foreign matter flows into the fuel tank, the foreign matter can be collected in a foreign matter reservoir, and clogging of the fuel suction pump due to foreign matter can be prevented as much as possible. Furthermore, even if the suction pump becomes clogged, when the pressure in the return piping increases, the relief valve opens at a set pressure lower than the pressure regulator to relieve the pressure in the return piping. It is possible to prevent the inside of the return pipe from becoming high pressure, and it is possible to stabilize the fuel pressure control operation of the pressure regulator.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. In the embodiment, the same components as those of the prior art shown in FIGS. 3 and 4 are given the same reference numerals, and their explanations will be omitted.

In the figure, 21 indicates a relief valve located in the fuel tank 1 and provided in the middle of the return pipe 17, and the valve casing 22 of the relief valve 21 is located in the second
As shown in the figure, it is formed into a cylindrical shape with a bottom, and its upper end is covered with a cover 23. and,
The space between the valve casing 22 and the cover 23 is defined by a diaphragm 24 into an oil chamber 25 and a spring chamber 26, and the peripheral wall of the valve casing 22 is designed to drain excess oil from the return pipe 17 into the oil chamber 25. An inlet 22A and an outlet 22B for inflow and outflow are provided to protrude in the radial direction. In addition, the valve casing 22
An annular foreign matter reservoir 22C is formed on the bottom side of the oil chamber 22, projecting downward so as to surround the lower end side of a relief pipe 30, which will be described later, and communicating with the oil chamber 25.

Here, the inlet 22A side and the outlet 22B side of the valve casing 22 are connected to the middle of the return piping 17 as shown in FIG.
It is provided in the valve casing 22 offset upwardly by a predetermined distance H with respect to the 2A side. Then, the excess oil from the return pipe 17 is removed from the inlet 22A.
The fuel flows into the oil chamber 25 from the side, collects foreign matter 20 and the like in the foreign matter reservoir 22C, and flows out from the outlet 22B side to the fuel suction pump 18 side.

27 is a spring receiver 28 in the center of the diaphragm 24.
The valve body 29 is located in the spring chamber 26 and is disposed between the spring receiver 28 and the cover 23, and the valve spring 29 connects the valve body 27 with the valve body 27 as described below. The valve seat 30A side is always biased, and the valve opening pressure of the valve body 27 is adjusted to the set pressure of the pressure regulator 12 (2.55
(Kg/ ^cm2 ), for example, about 0.8Kg/ ^cm2 . The valve body 27 is opened by the diaphragm 24 when the fuel suction pump 18 is clogged with foreign matter 20 and the pressure inside the oil chamber 25 exceeds 0.8 kg/cm ² .
7 is designed to prevent the pressure inside it from becoming any higher.

Reference numeral 30 indicates a relief pipe that is integrally provided in the valve casing 22 so as to pass through the bottom side of the valve casing 22 upward and downward, and the upper end side of the relief pipe 30 is connected to the inside of the oil chamber 25 by an inlet 22A and an outlet 22B. The end face extends upward to a higher position than the valve body 27.
serves as a valve seat 30A that is seated and removed. Further, the lower end side of the relief pipe 30 projects downward from the valve casing 22 and is connected to the base end side of a relief pipe 31 extending into the main tank 1A. The relief pipe 30 drains excess oil from the return pipe 17 to the relief pipe 31 when the valve body 27 is opened.
It is designed to be relieved to the main tank 1A side via.

The fuel injection device according to this embodiment has the above-described configuration, and its basic operation is not particularly different from that of the prior art.

However, in this embodiment, a relief valve 21 is provided in the middle of the return pipe 17, and the valve casing 22 of the relief valve 21 is located between the inlet 22A and the outlet 22B, and has oil on the bottom side of the valve casing 22. An annular foreign matter reservoir 22C communicating with the chamber 25 is formed, and an inlet 22A and an outlet 22 of the valve casing 22 are connected to each other.
B is offset upward and downward by a predetermined distance H, so excess oil from the return pipe 17 flows into the oil chamber 25 from the inlet 22A and is guided so as to collide with the peripheral wall of the valve casing 22. At the same time, the foreign matter 20, etc. that flows out from the outlet 22B and flows into the oil chamber 25 together with excess oil can be reliably collected in the foreign matter reservoir 22C as shown in FIG. It is possible to prevent the fuel from flowing out from the fuel suction pump 22B and clogging the fuel suction pump 18 as much as possible.

In addition, even if the suction pump 18 is clogged with foreign matter 20 as in the prior art, the valve body 27 of the relief valve 21 is removed from the valve seat 30A of the relief pipe 30.
For example, since the oil chamber 25 is seated at a set pressure of about 0.8Kg/cm ² , the pressure inside the oil chamber 25 is 0.8Kg/cm ^{2 .}
If this level is exceeded, the valve body 27 automatically opens to relieve the pressure inside the oil chamber 25, and the return piping 1
It is possible to reliably prevent the pressure inside the pressure regulator 7 from increasing to 0.8 kg/cm ² or more, and the fuel pressure control by the pressure regulator 12 can be stabilized. In this case, the foreign matter 20 etc. are collected in the foreign matter reservoir 22C and the valve seat 30A is located higher than the inlet 22A and outlet 22B, so the foreign matter 20 etc. are collected in the valve body 22C.
It is also possible to prevent clogging between the valve seat 30A and the valve seat 30A, and to solve problems such as excessive pressure acting on each injection valve 13 etc. when the return pipe 17 is in a low pressure state.

In the above embodiment, the inlet 22A and the outlet 22B of the valve casing 22 are offset upwardly and downwardly, but instead of this, the inlet 22A and the outlet 22B are offset upwardly and downwardly.
A and the outlet 22B may be offset in the circumferential direction of the valve casing 22, for example by arranging them at right angles.

Further, in the embodiment described above, the relief valve 21 is provided inside the fuel tank 1, but instead of this, the relief valve 21 may be provided outside the fuel tank 1 in the middle of the return pipe 17. .

Furthermore, in the embodiment described above, the annular foreign matter reservoir 22C is formed in the valve casing 22 of the relief valve 21, but the foreign matter reservoir 22 does not necessarily have to be formed in an annular shape, and the bottom side of the valve casing 22 is You can just use it as the bottom.

[Effect of idea]

As detailed above, according to the present invention, a relief valve is provided in the middle of the return piping, and a foreign matter reservoir is formed in the valve casing of the relief valve between the inlet and the outlet. Foreign matter from the return piping can be collected in a foreign matter reservoir, preventing clogging of the fuel suction pump as much as possible, and even if such clogging occurs, the relief valve can be opened to relieve the pressure in the return piping. This eliminates problems such as excessive pressure acting on the injection valve and causing rich engine stall, and provides a fail-safe function.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention,
FIG. 1 is a vertical sectional view showing the main parts of a fuel injection device, FIG. 2 is a vertical sectional view of the relief valve shown in FIG. 1, FIGS. 3 and 4 show the conventional technology, and FIG. FIG. 4 is an overall configuration diagram of the fuel injection device, and FIG. 4 is a longitudinal cross-sectional view of the fuel suction pump shown in FIG. 3. 1...Fuel tank, 1A...Main tank, 1
B...Subtank, 9...Fuel pump, 10...
Discharge piping, 12...Pressure regulator, 13...
Injection valve, 14... Supply piping, 17... Return piping, 18... Fuel suction pump, 20... Foreign object, 2
1... Relief valve, 22... Valve casing, 22
A...Inlet, 22B...Outlet, 22C...Foreign matter reservoir, 23...Cover, 25...Oil chamber, 26...Spring chamber, 27...Valve body, 30...Relief pipe, 30
A...Benza.

Claims (1)

[Scope of utility model claims] A fuel tank consisting of a main tank and a sub-tank, a fuel pump provided on the main tank side of the fuel tank, a supply pipe that supplies fuel discharged from the fuel pump to the injection valve, and a fuel pressure inside the supply pipe. A pressure regulator to be adjusted; a return pipe for returning excess oil from the pressure regulator to the main tank side of the fuel tank; In a fuel injection device consisting of a fuel suction pump that sucks fuel inside the tank into the main tank, a foreign matter reservoir is located in the valve casing between the inlet and the outlet of the surplus oil in the middle of the return piping. A fuel injection device comprising: a relief valve that relieves pressure in the return pipe at a set pressure lower than that of the pressure regulator.