JPS59170466A - Fuel injection device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent fuel from a fuel pressure adjusting chamber from flowing into a suction passage due to a crack of a diaphragm by connecting a reference pressure chamber formed by diaphragms with a fuel tank. CONSTITUTION:A pressured fuel from a fuel pump 12 flows into a fuel pressure adjusting chamber 34 of a fuel pressure adjusting device 14 via a fuel conducting pipe 20 and an inlet nipple 22. If a fuel pressure reaches over the value fixed by a pressure spring 54, a diaphragm 32, retaining bodies 38 and 40 are displaced against the pressured spring by the fuel pressure. As the result, the close sealing of a valve seat 44 and a removable valve board 52 is released to connect a fuel return passage 42 through. This construction permits the fuel inside the fuel pressure adjusting chamber 34 to flow ito a reference pressure chamber 36 via a fuel passage 42 and return it to a fuel tank 10 via an outlet nipple 24 and a fuel conducting pipe 26.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a fuel pressure regulating device for a fuel injection device for an internal combustion engine.

[Prior art]

In a fuel injection system for an internal combustion engine, it is important to keep the pressure of the fuel supplied to the fuel injection valve constant in order to fully inject the amount of fuel that matches the operating condition of the internal combustion engine. A fuel pressure regulator is required.

Conventionally, this Yuzu's fuel pressure glA! A well-known adjustment device is the one described in Japanese Patent Publication No. 5133/1983.

However, in such a fuel pressure regulating device, the reference pressure chamber formed on the other side of the diaphragm, which forms the fuel pressure regulating chamber for fully regulating the fuel pressure, is connected to the intake passage. When a crack occurs in the fuel pressure adjustment chamber, does the fuel flow into the reference pressure chamber? This caused the problem that the air-fuel mixture became abnormally rich as it flowed into the intake passage.

Furthermore, if the cracks in the diaphragm become large enough to break, a large amount of fuel will flow into the intake passage, leading to a serious accident in which the internal combustion engine will not be able to operate and the risk of fire will increase.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel injection bag for an internal combustion engine that prevents fuel from the fuel pressure adjustment chamber from flowing into the intake passage even if a crack occurs in the diaphragm that constitutes the entire fuel pressure adjustment device.

[Summary of the invention]

A feature of the present invention is that the reference pressure chamber formed by the diaphragm is connected to all fuel tanks. According to the present invention, even if a crack occurs in the diaphragm, fuel is returned to the fuel tank, so that fuel no longer flows into the intake passage.

[Embodiments of the invention]

FIG. 1 shows the configuration of a fuel injection system for an internal combustion engine to which the fuel pressure regulating device of the present invention is fully applied. 2 is an intake passage, and this intake passage 2 is provided with a throttle valve 4 and a fuel injection valve 6.

A valve opening signal is inputted to the fuel injection valve 6 from a control device 8 (generally a stored program type digital computer is adopted), and the opening time of the fuel injection valve 6 is determined according to this valve opening signal. On the other hand, fuel from a fuel tank 10 is supplied to the fuel injection valve 6 after being pressurized by a fuel pump 12, and the pressure of this fuel is adjusted to a constant value by a fuel pressure regulator 14. There is.

Pressurized fuel from the fuel pump 12 is supplied to the fuel injection valve 6 through a fuel conduit 16, and the fuel conduit 2° that branches off from this fuel conduit 16 at a branch portion 18 is connected to a fuel pressure regulator 140 artificial nipple. 22, and when the pressure of the pressurized fuel from the fuel pump 12 becomes greater than a predetermined value, the fuel is released from the outlet nipple 24 of the fuel pressure regulator 14! Since the fuel is released and returned to the fuel tank 1o via the fuel conduit 26Y, the fuel is maintained at a constant pressure value.

The entire fuel pressure regulating device will be explained based on FIG. 2.

A diaphragm 32 is fixed between the casing 28 and the casing 3o, the n1 casing 28 and the diaphragm 32 form a fuel pressure adjustment chamber 34, and the casing 3o and the diaphragm 32 form a reference pressure chamber 36.

An inlet nipple 22 opens into the fuel pressure adjustment chamber 34 , and an outlet nipple 24 opens into the reference pressure chamber 36 .

Here, the artificial nipple 22 and the outlet nipple 24 are fixed to the casings 28, 30 parallel to each other and at right angles to the direction of displacement of the diaphragm 32.

With this configuration, the length of the fuel pressure regulator 14 in the vertical direction, that is, in the direction of displacement of the diaphragm can be completely shortened, and the effect of facilitating the arrangement in the arrangement chamber of the internal combustion engine can be obtained.

Holders 38 and 40 are respectively fixed to the central part of the diaphragm 32. The holder 38 is provided with a fuel return passage 42 that communicates with the fuel pressure chamber 34 and the reference pressure chamber 36.
, and a valve seat 4 is provided on the fuel pressure chamber 34 side of the fuel return passage 42.
4 is formed.

A storage member 46 is fixed to the center of the casing 28,
In this storage member 46, a ball 50 is rotatably stored, one end of which is fixed to the storage member 46 and supported by a sheltered stopper 48, and a movable valve plate 52 is fixed to the ball 50. Therefore, the movable valve plate 52 can pivot around the ball 50 as a fulcrum. The movable valve plate 52 has a function of fully opening and closing the fuel return passage 42 by being excited with the valve seat 44.

On the other hand, a compression spring 54 is disposed within the reference pressure v36 to obtain the required fuel pressure 2, and this compression spring 54 is connected to the diaphragm 32 and the holders 38, 40.
It moves one time so as to press toward the movable valve plate 52 side.

In the above, the pressurized fuel from the fuel pump 12 passes through the fuel conduit 20 and the inlet nipple 22 and flows into the fuel pressure adjustment chamber 34 of the fuel pressure adjustment device [14]. When the fuel pressure reaches a value greater than or equal to the value defined by the compression spring 54, the diaphragm 32 and the holder 38, 40 are displaced by the fuel pressure against the compression spring. As a result, the seal between the valve seat 44 and the movable valve plate 52 is released, and the fuel return passage 42 is brought into communication. Therefore, the fuel in the fuel pressure adjustment chamber 34 passes through the entire fuel passage 42 and reaches the reference pressure chamber 3.
6, the fuel is returned to the fuel tank 10 through an outlet nipple 24 and a fuel conduit 26.

At this time, the pressure of the fuel in the fuel pressure adjustment chamber 34 has fallen below the value specified by the compression spring 54, so the diaphragm 32 and the holder 38, 40 are moved toward the movable valve plate 52 by the force of the compression spring 54. Displaced, the valve seat 44
This ensures that the movable valve plate 52 is sealed tightly.

By repeating the above steps, the pressure within the fuel pressure adjustment chamber 34 is maintained constant.

FIG. 3 shows a second modification of the embodiment shown in FIG. 2, and the same reference numerals as in FIG. 2 indicate the same ones.

A storage member 46A is fixed to the center of the casing 28, and a ball 50A is fixed to the tip thereof. A movable valve plate 52A having a concave portion is placed over the ball 50A, and the movable valve plate 52A is placed between the ball 50A and a compression spring 56 disposed between the holding member 38 and the movable valve plate 52A.
A is rotatably supported.

In the non-embodiment, as in the embodiment shown in FIG. 2, when the fuel pressure in the fuel pressure adjustment chamber 34 reaches a specified level or higher, the fuel flows from the fuel pressure adjustment chamber 34 through the entire fuel return passage 42 to the reference pressure chamber. 36 and is further returned to the fuel tank 10 through the outlet nipple 24 and the fuel conduit 26.

FIG. 4 shows all other modified examples, and the same reference numerals as in FIG. 2 indicate all the same parts.

A pipe forming a fuel return passage 42B is completely open in the fuel pressure adjustment chamber 34, and a movable valve plate 52B held by a holder 38, 40 and a compression spring 56B is pressed into contact with the pipe. Of course, the movable valve plate 52B is rotatably supported by the ball 50B.

In this embodiment, when the fuel pressure in the fuel pressure adjustment chamber 34 reaches a specified level or higher, the diaphragm 32 is displaced, the movable valve plate 52i (the fuel return 1 passage 42B is fully opened, and the fuel flows to the fuel tank lo side). It will be returned.Of course,
In this embodiment as well, if a crack occurs in the diaphragm 32 and fuel flows into the reference pressure chamber 36, this fuel will flow through the outlet nipple 2.
4. Returned to fuel tank 10 via fuel conduit 26.

〔Effect of the invention〕

According to the present invention, since the reference pressure chamber of the fuel pressure regulating device is communicated with all the fuel tanks, it is possible to completely prevent fuel from flowing into the intake passage due to cracks in the diaphragm.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a fuel injection system for an internal combustion engine employing the fuel pressure regulator Y according to the present invention, Fig. 2 is a sectional view of the fuel pressure regulator, and Figs. 3 and 4 are modifications of Fig. 2. FIG. 2 is a sectional view of a fuel pressure regulating device. 6...Fuel injection valve, 10...Fuel tank, 12...
・Fuel pump, 16, 20.26... Fuel conduit, 14
...Fuel pressure adjustment device, 34...Fuel pressure adjustment chamber,
36...Reference pressure chamber.

Claims (1)

[Claims] 1. A fuel injection valve provided in an intake passage of an internal combustion engine;
A damping device that provides a valve opening signal necessary for a fuel injection valve;
A fuel pump that fully pressurizes and supplies fuel from the fuel tank to the fuel injection valve, and a fuel pressure adjustment device that controls the pressure of the pressurized fuel from the fuel pump to be constant? In the fuel injection device for an internal combustion engine, the fuel pressure regulating device has a fuel pressure regulating chamber and a reference pressure chamber partitioned by a diaphragm, and the fuel pressure regulating chamber is injected with fuel through the fuel pump and the first conduit. A fuel injection device for an internal combustion engine, characterized in that the reference pressure chamber is connected to the front Me fuel tank via a 22nd jl pipe. 2. Claim 1. In the above, the fuel pressure adjustment chamber is formed by the diaphragm p+iJ and the first casing, the reference pressure chamber 1qil is formed by the diaphragm and the second casing, and the pressure of the fuel in the fuel pressure adjustment chamber is equal to or lower than the reference pressure chamber. When the value exceeds the value specified by , an opening/closing means fixed to the diaphragm opens the fuel return passage connecting all the fuel pressure adjustment chambers and the fuel tank, and all of the fuel in the fuel pressure adjustment chamber is transferred to the fuel tank. A fuel injection device for an internal combustion engine, characterized in that the fuel injection device is configured to return the fuel. 3. In claim 2, the opening/closing means fixed to the diaphragm is a valve body supported by a holding body fixed to the diaphragm, and the fuel return passage is fixed to the first casing. A fuel injection device for an internal combustion engine, characterized in that the pipe extends to the fuel pressure adjustment chamber. 4. In claim 2, the opening/closing means fixed to the diaphragm includes a holder 2 having a fuel return passage 2 communicating between the fuel pressure adjustment chamber and the reference pressure chamber, A fuel for an internal combustion engine, characterized in that a valve body for opening and closing the fuel return (7 passages) formed in the holding body is arranged, and the valve body is supported by the first casing. Injection device. 5. A fuel injection bag for an internal combustion engine, characterized in that the valve body is rotatably supported in claim 3 or 4! 6. Claim 5 wherein the artificial nipple is fixed to the first casing that fully connects the fuel pressure adjustment chamber and the first conduit; and the artificial nipple is fixed to the second casing that fully connects the reference pressure chamber and the second conduit. A fuel injection device for an internal combustion engine, characterized in that the diaphragms are parallel to each other and have a relationship 2 perpendicular to the direction of displacement of the diaphragm.