JP2525751Y2 - Fuel supply device for internal combustion engine - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply device for an internal combustion engine having a side-feed type fuel injection valve used in a multipoint injection system for an internal combustion engine.

[0002]

2. Description of the Related Art As shown in FIG. 3, a fuel injection valve 1 for supplying fuel to an internal combustion engine is provided in a mounting hole 3 formed through a wall of an intake manifold 2 of the engine. Mounted to jet. Reference numeral 5 denotes an exhaust valve. In recent years, as a mounting structure of the fuel injection valve 1, a structure as shown in FIG. 4 has been adopted for simplification of the structure and improvement of heat-resistant restartability (see Japanese Utility Model Laid-Open No. Hei 3-13462).

[0003] That is, the casing 6 is provided in the middle of the pipe 8 in a direction orthogonal to the pipe 8, and the internal space of the casing 6 communicates with the internal space of the pipe 8 through the opening 7 on the side thereof. . The pipe 8 is connected at one end to the discharge side of a fuel pump that sucks and discharges fuel from a fuel tank (not shown), and is connected at the other end to a return pipe to the fuel tank via a pressure regulator.

In the casing 6, a fuel injection valve 1 having a fuel inlet 9 with a filter on the side is opened, and a front O-ring 10 and a base O-ring 10 arranged at the front end and the base end of the fuel inlet 9, respectively. It is stored via an end O-ring 11.
Further, the tip of the fuel injection valve 1 protrudes from the tip of the casing 6. Distal O-ring 10 and Proximal O-ring
The space between the casing 6 and the fuel injection valve 1 partitioned by 11 is a reservoir 12 for the fuel supplied from the pipe 8.

[0005] The base end of the fuel injection valve 1 is made of a rubber insulator for preventing vibration transmission by opening and closing of the needle valve by a pressing member 13 screwed to the casing 6.
A rubber spacer 16 for preventing vibration transmission by opening and closing the needle valve is similarly provided at the base end of the casing 6 at the rear end of the side of the fuel injection valve 1. It is locked by retaining through.

The front end of the casing 6 of the fuel supply device as described above is fitted through a rubber-made annular insulator 17 into a mounting hole 3 formed through the wall of the intake manifold 2 for fuel injection. The valve 1 is exposed in the intake passage. The fuel introduced into the fuel injector 1 from the reservoir 12 through the fuel inlet 9 is urged in the valve closing direction by a spring (not shown), and is driven in the valve opening direction by excitation of an electromagnet. Is injected toward the intake valve 4 in the intake manifold 2 when the valve is opened.

[0007]

However, such a conventional apparatus has a dead volume (X position in the figure) around the tip of the fuel injection valve 1, so that the particulate fuel is wound up here. When the fuel accumulates and accumulates in a certain amount, the fuel becomes a droplet and is sucked into the cylinder. As shown in FIG. 5, the horizontal axis represents time, and the vertical axis represents the air-fuel ratio. (Y position in the figure), the stability at the time of idling is deteriorated, and in the worst case, there is a possibility that the engine stalls, the exhaust emission also deteriorates, and the drivability becomes poor.

The present invention has been made in view of the above problems, and has as its object to provide a fuel supply device having a structure in which fuel does not accumulate at the tip of a fuel injection valve.

[0009]

In order to achieve the above object, the present invention provides a fuel injection valve having a fuel inlet opening on a side in a cylindrical casing provided in the middle of a fuel pipe. The fuel supply of the internal combustion engine is performed by inserting the front end of the casing into a mounting hole formed through the wall of the intake manifold through an annular insulator. In the device, the insulator tip is provided with a reduced diameter portion that covers the tip of the casing and whose inner circumference is close to the outer circumference of the tip of the fuel injection valve.

[0010]

According to the above construction, at the tip of the insulator,
Since the reduced diameter portion is provided to cover the front end of the casing, and the inner periphery thereof is close to the outer periphery of the fuel injection valve front end portion,
There is no step around the tip of the fuel injection valve, and there is no space (dead volume) in which fuel accumulates.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a first embodiment. The fuel injection valve 1 is housed in the casing 6 with its tip protruding from the tip of the casing 6. The casing 6 has its distal end inserted into a mounting hole 3 formed through the wall of the intake manifold 2 via a rubber annular insulator 17 disposed on the step 3a. At the tip of the insulator 17, a ring-shaped rubber sheet 18 having a central hole 18a as a reduced diameter portion is provided between the insulator 17 and the step portion 3a. Rubber sheet 18
Covers the front end of the casing 6, the inner periphery of the center hole 18a is close to the outer periphery of the front end of the fuel injection valve 5, and the front end of the fuel injection valve 1 faces the intake manifold 2 from the center hole 18a.

By providing the rubber sheet 18, there is no step around the tip of the fuel injection valve 1 and there is no dead volume, so that accumulation of fuel is eliminated. Also,
FIG. 2 shows a second embodiment. This is substantially the same as in the first embodiment, and the reduced diameter portion 19 is formed integrally with the insulator 17 so that the inner circumference 19a is close to the outer circumference of the tip of the fuel injection valve 1.

In this case, the same operation and effect can be obtained.

[0014]

[Effect of the invention] As described above, according to the invention,
A reduced diameter portion is formed at the tip of the insulator so that its inner periphery is close to the outer periphery of the tip of the fuel injection valve, so that there is no step around the tip of the fuel injection valve and there is a space (dead volume) where fuel accumulates. Disappears.

Therefore, it is possible to avoid the enrichment due to the accumulated fuel, improve the stability at the time of idling, improve the exhaust characteristics, and improve the operability.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fuel injection valve according to a first embodiment of the present invention;

FIG. 2 is a cross-sectional view of the vicinity of the tip of a fuel injection valve, showing a second embodiment.

FIG. 3 is a sectional view showing a fuel injection valve and an intake manifold.

FIG. 4 is a cross-sectional view of a fuel injection valve and its periphery showing a conventional example.

FIG. 5 is a diagram showing a conventional problem.

[Explanation of symbols]

 1 Fuel injection valve 17 Insulator 3 Mounting hole 18 Rubber sheet 19 Reduced diameter part

Claims (1)

(57) [Scope of request for utility model registration] 1. A fuel injection valve having a fuel inlet opening at a side portion thereof is housed in a cylindrical casing provided in the middle of a fuel pipe, with a tip end portion of the fuel injection valve projecting from a tip end of the casing. In a fuel supply device for an internal combustion engine, wherein a tip of the casing is inserted into a mounting hole formed through a wall of a manifold via an annular insulator, the tip of the insulator covers the tip of the casing, and A fuel supply device for an internal combustion engine, wherein a reduced diameter portion whose inner circumference is close to the outer circumference of a tip portion of the fuel injection valve is provided.