JPH06147059A - Fuel supply system of internal combustion engine - Google Patents

Abstract

PURPOSE:To carry out a stable fuel supply in various driving regions, in a fuel supply system of an internal combustion engine supplying atomized air by means of differential pressure between atmospheric pressure and inlet negative pressure. CONSTITUTION:An extending part 31 is formed at the tip side of a foreflow part 1d of a fuel injection valve 30, and a venturi part 35 is installed in a tip part of the extending part 31. In addition, each axis of the extending part 31 and the venturi part 35 points to a shade part 9a of an inlet valve 9 and an inlet valve opening part 10, while an upstream side opening part 35a of the venturi part 35 is opened vertically with an axis 3c of an inlet port 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved fuel supply system for an internal combustion engine.

[0002]

2. Description of the Related Art A fuel supply device for an internal combustion engine has been conventionally used to improve atomization and atomization of fuel and stabilize combustibility for the purpose of improving fuel economy and exhaust gas purification performance. For example, there is one as shown in FIG. In the figure, the fuel injection valve 1 introduces air into the air inlet 1a of the fuel injection valve 1 by the pressure difference between the atmospheric pressure upstream of the throttle valve (not shown) and the suction negative pressure in the intake pipe 2, This is a so-called air-assisted injection valve that atomizes the fuel introduced by air through the fuel inlet 1b. The fuel injection valve 1 shown in the figure atomizes the fuel with air and
In order to reduce the adhesion of fuel to the inner wall 3a of the intake port 3 as much as possible, a run-up portion 1d is formed as a spray run-up section up to the injection valve injection port portion 1c. Where the fuel injection amount
The injection timing is adjusted and controlled by the controller 1e.

[0003]

However, in the fuel supply device for the internal combustion engine which supplies the assist air by the differential pressure between the atmospheric pressure and the suction negative pressure, the air pump for atomizing air is not necessary. However, since the suction differential pressure varies widely in various operating regions, the atomizing air cannot be stably supplied. In particular, when the throttle valve is fully opened, there is no suction differential pressure, so that the fuel atomization level is lowered, and thus the mixture formation is insufficient and combustion, fuel consumption, exhaust gas, etc. may be impaired.

On the other hand, as shown in FIG. 5, there is a technique of atomizing fuel by a venturi when assist air is not supplied (see Japanese Utility Model Laid-Open No. 61-88062). That is, on the tip side of the injection port 20a of the fuel injection valve 20, the injection port
A fuel supply passage 21 extending from 20a and having an open end is provided in the intake passage 27. Further, the intake passage 27 of the fuel supply passage 21 is provided.
This is a technique in which a venturi portion 23 is provided at the opening position and the fuel is atomized by the venturi portion 23.

However, the venturi portion 23 is replaced by the intake valve 25.
The atomized spray does not go from the umbrella portion 25a toward the opening 26 and adheres to the inner wall 24 of the intake port to form a wall flow. In addition, since the venturi portion 23 is separately provided at the opening position of the intake passage 27 of the fuel supply passage 21, there is a problem that the number of assembling steps and the like increase and the manufacturing cost increases.

The present invention has been made by paying attention to such a conventional problem, and in a fuel supply system for an internal combustion engine, which supplies air for atomization by a differential pressure between atmospheric pressure and suction negative pressure, It is an object of the present invention to provide a fuel supply device for an internal combustion engine, which is capable of stably supplying fuel in various operating regions by integrally providing a venturi portion in the injection port portion, and which improves fuel consumption and exhaust characteristics.

[0007]

Therefore, the present invention is directed to a fuel supply system for an internal combustion engine which supplies air for atomization by a pressure difference between the upstream side pressure and the downstream side pressure of an intake system throttle valve. A venturi portion having an opening in the flow is disposed in the fuel injection valve nozzle so that the opening on the upstream side opens perpendicularly to the streamline of the intake air flow, and the venturi portion and the nozzle portion. Is directed toward the intake valve umbrella portion and the intake valve opening portion.

[0008]

According to the above construction, when the throttle valve is not fully opened, the atomizing air is guided to the fuel injection valve by the pressure difference between the upstream pressure and the downstream pressure of the throttle valve, and the fuel is air. Is mixed and accelerated, and is injected from the injection port of the fuel injection valve. When the throttle valve is fully opened, the suction differential pressure does not occur, so the atomizing air is not guided by the differential pressure, but the flow rate in the intake pipe is large and the flow velocity is high. Here, since the venturi portion arranged at the fuel injection valve injection port portion has an opening on the upstream side opened perpendicularly to the streamline of the intake air flow, a large amount of air flows into the venturi portion. It will be. Therefore, when a large amount of high-speed fluid flows into the venturi portion, the ejector effect of the fluid (air) acts to suck the fuel and simultaneously atomize the fuel.

Further, since the venturi portion and the injection port portion are provided so as to face the intake valve head portion and the intake valve opening portion, the fuel mixed with the air injected from the fuel injection valve injection portion due to the differential pressure is used. Alternatively, the fuel atomized by the ejector effect of the venturi portion is injected toward the intake valve umbrella portion and the intake valve opening portion.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. The same components as those of the fuel injection valve 1 shown in FIG. 4 described in the conventional example are designated by the same reference numerals and the description thereof will be omitted. Figure 1
The first embodiment according to the present invention is shown in FIG. In the fuel injection valve 30 according to the first embodiment, the extension portion 31 is formed on the leading end side of the approach portion 1d so as to project into the intake air flow in the intake port 3. Then, as shown in FIG. 2, a venturi portion 35 is provided at the tip of the extension portion 31 by a column 37 outside the extension portion 31.

Here, the axes of the extension portion 31 and the venturi portion 35 are directed to the umbrella portion 9a of the intake valve 9 and the intake valve opening portion 10, and the upstream opening portion 35a of the venturi portion 35 is connected to the intake port 3a. The opening is perpendicular to the axis 3c. Next, the operation according to this embodiment will be described. When the throttle valve (not shown) is not fully opened, the atomizing air is guided to the fuel injection valve 30 from the air inlet 1a by the pressure difference between the upstream pressure and the downstream pressure of the throttle valve, and the fuel is It is mixed and accelerated with air, and is injected from the run-up part 1d, the extension part 31, and the fuel injection valve injection port part 31c. When the throttle valve is fully opened, the suction differential pressure does not occur, so the atomization air is not guided by the differential pressure, but the flow rate in the intake port 3 is large and the flow velocity is also high. Where the venturi part 35
Since the upstream side opening 35a of the intake port 3 is opened perpendicularly to the axis 3c of the intake port 3, it is opened perpendicularly to the streamline of the intake air flow, and a large amount of air is generated in the venturi part 35. Will flow into. Therefore, a large amount of high-speed intake air flows into the venturi portion 35,
The ejector effect of the intake air acts to atomize the fuel.

Further, since the axes of the extension portion 31 and the venturi portion 35 are directed toward the umbrella portion 9a of the intake valve 9 and the intake valve opening portion 10, the atomized fuel ejected from the fuel injection valve injection port portion 31c is Without adhering to the inner wall 3a of the intake port 3,
It will be supplied into the combustion chamber 11. Therefore, as the air for atomizing, the air generated by the suction differential pressure is used as the fuel injection valve.
Introduced into 30 and used, when the throttle valve is fully opened, the flow in the intake port 3 is used, and the venturi part 35 provided integrally with the extension part 31 serves as a fuel supply device for atomizing the fuel Not only when the negative pressure is large,
Even when the throttle valve is fully opened, sufficient atomization air can be secured, and atomization can be promoted.

Further, since the directions of the extension portion 31 and the venturi portion 35 are defined so as to be directed toward the umbrella portion 9a of the intake valve 9 and the intake valve opening portion 10, the atomized fuel adheres to the inner wall 3a of the intake port 3. It will be supplied into the combustion chamber 11 without doing so. Therefore, it is possible to prevent the formation of the fuel wall flow in the intake port 3 and the combustion chamber 11 and increase the space floating rate of the fuel in any operating condition. Therefore, there is an effect that the problem of transient response due to the fuel wall flow can be solved, stable combustion can always be performed, and operation with good fuel consumption and exhaust can be performed.

Further, in the present embodiment, since the venturi portion 35 is integrally arranged by the column 37 outside the tip end portion of the extension portion 31, the venturi portion when the fuel injection valve 30 is attached to the intake port 3 is provided. The 35 has good wearability, and there is also an effect that the manufacturing cost can be reduced. Next, a second embodiment according to the present invention will be described based on FIG.
The fuel injection valve 30 shown in FIG. 1 described in the first embodiment is used.
The same components as those in FIG.

In the fuel supply system according to the second embodiment, the partition wall 5 is provided on the downstream side of the swirl control valve 4 provided in the intake pipe 2. According to this configuration,
The intake air flow that has passed through the swirl control valve 4 is rectified by the partition wall 5 and flows into the venturi portion 35 without causing any turbulence, so that a large amount of air can be efficiently introduced into the venturi portion 35. Therefore, it becomes possible to promote atomization.

[0016]

As described above, according to the present invention, in the fuel supply system for the internal combustion engine which supplies the air for atomization by the differential pressure between the upstream side pressure and the downstream side pressure of the intake system throttle valve. A venturi portion having an opening in the intake air flow is arranged in the fuel injection valve nozzle so that the opening on the upstream side opens perpendicularly to the streamline of the intake air flow, and the venturi portion is provided. Further, since the injection port portion is provided so as to be directed toward the intake valve umbrella portion and the intake valve opening portion, there is an effect that fuel can be stably supplied in various operating regions, and fuel consumption and exhaust characteristics can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the configuration of a first embodiment of a fuel supply system of the present invention.

FIG. 2 is a front view as seen from the direction of arrow A in FIG.

FIG. 3 is a vertical cross-sectional view showing the configuration of a second embodiment of the fuel supply system of the present invention.

FIG. 4 is a vertical sectional view showing a configuration of a conventional fuel supply device.

FIG. 5 is a vertical cross-sectional view showing the configuration of a conventional fuel supply device.

[Explanation of symbols]

 1a Air inlet 1d Run-up part 3 Intake port 9 Intake valve 10 Intake valve opening 30 Air-assisted fuel injection valve 31 Extension part 35 Venturi part 35a Upstream side opening

Claims (1)

[Claims] 1. A fuel supply device for an internal combustion engine, which supplies air for atomization by a pressure difference between an upstream pressure and a downstream pressure of an intake system throttle valve, wherein a venturi portion having an opening in an intake air flow is provided. , The upstream side opening is arranged at the fuel injection valve injection port so that it opens perpendicularly to the flow line of the intake air flow, and the venturi part and the injection port are the intake valve umbrella part and the intake valve opening part. A fuel supply device for an internal combustion engine, wherein the fuel supply device is provided so as to face the engine.