JPH06317236A - Fuel injection device - Google Patents

Abstract

PURPOSE:To provide a fuel injection device in which opening of throttle valve can be adjusted easily at idling time. CONSTITUTION:In a fuel injection device 6 to promote atomization of fuel by mixing assist air in fuel injected directly into an intake air passage 9 of an engine, a throttle valve 11 is arranged in the intake air passage 9, on the one hand, an assist air taking-in port 21 to be opened in the intake air passage 9 is arranged downstream of the throttle valve 11, and a flow rate of the assist air taken in from the taking-in port 21 is regulated by the throttle valve 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device, and more particularly to a fuel injection device which facilitates adjustment of a throttle valve opening during idling.

[0002]

2. Description of the Related Art A carburetor is used as a means for supplying an air-fuel mixture to an engine. The carburetor is located in the middle of the intake passage of the engine, and uses the flow of air drawn by the engine to suck the fuel out of the chamber inside the carburetor, atomize it, and mix it with the air to create a mixture of fuel and air inside the engine. I am sending it to.

The carburetor is trying to obtain the best setting by combining a number of jets in order to meet the characteristics of the engine and the demands of running, but it adapts flexibly to changes in operating conditions and the surrounding environment. It was impossible to do.

Therefore, in recent years, a sensor detects a throttle opening, an engine speed, an engine temperature, an outside air temperature and an atmospheric pressure, and the information is processed by a computer so that the most appropriate necessary fuel amount at that time is directly supplied to an intake passage of the engine. The number of engines equipped with a fuel injection device for injection has increased.

[0005] The fuel injection device has the advantages that the combustion efficiency is good and the output is improved, but the fuel consumption is small because the fuel is injected in the minimum required amount. However, in order to increase the combustion speed of the air-fuel mixture and further improve the output, it was necessary to promote atomization of the injected fuel.

Therefore, the main body of the fuel injection device has been improved, and a reflector (baffle plate) has been provided in the vicinity of the fuel injection hole to apply fuel to the reflector to promote atomization.

Further, there is also a technique for introducing assist air from the intake passage by utilizing the intake negative pressure of the engine and mixing the assist air with the fuel directly injected into the intake passage to promote atomization of the fuel. It was

[0008]

However, the atomization of fuel is limited only by the improvement of the fuel injection device main body, and the output is inferior to that of the engine using the conventional carburetor particularly in the high speed rotation range of the engine. .

Further, when the reflector is provided near the fuel injection hole, the transient response is deteriorated, but in the low speed rotation range of the engine, a fuel pool or the like is generated and the rotation of the engine becomes unstable.

Further, when assist air is introduced from the intake passage by utilizing the intake negative pressure of the engine, the output of the engine can be improved, but conventionally, the intake port of the assist air is located upstream of the throttle valve. Since a portion of the intake negative pressure of the engine is provided for intake of assist air, the amount of air passing through the intake passage is reduced. Especially when idling, adjust the throttle valve opening to 0
It is necessary to adjust in a narrow range from 0 ° to 0 ° 30 ', and if the amount of air passing through the intake passage is small, a slight movement of the throttle valve will affect the rotation of idling. Adjustment becomes sensitive. If the adjustment of the throttle valve opening becomes sensitive, it becomes difficult to set the idling speed, and in the case of a multi-cylinder engine, there arises a problem that it becomes difficult to synchronize the speed of each cylinder, which is not preferable.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel injection device that facilitates adjustment of the throttle valve opening during idling.

[0012]

In order to solve the above-mentioned problems, the fuel injection device according to the present invention, as set forth in claim 1, uses assist air for fuel directly injected into the intake passage of the engine. In the fuel injection device for promoting the atomization of fuel by mixing the air intake valve with a throttle valve provided in the intake passage, an intake port for assist air opened in the intake passage is provided downstream of the throttle valve. It is provided.

In order to solve the above-mentioned problem, as described in claim 2, the flow rate of the assist air taken in from the intake port is regulated by the throttle valve.

[0014]

In the present invention having the above-mentioned structure, in the fuel injection device for promoting atomization of fuel by mixing assist air into the fuel directly injected into the intake passage of the engine,
A throttle valve is provided in the intake passage, an assist air intake opening in the intake passage is provided downstream of the throttle valve, and a flow rate of the assist air taken in from the intake passage is provided. Since the throttle valve is regulated by the throttle valve, it becomes easy to adjust the throttle valve opening when idling.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial side view showing an example of an engine to which the present invention is applied.

In FIG. 1, the engine 1 is provided with an engine exhaust system 2 on the left side of the figure and an engine intake system 3 on the right side of the figure. This engine intake system 3 is composed of an air cleaner 4, an intake pipe 5, and a fuel injection device 6. The upstream side of the intake pipe 5 is the air cleaner 4, and the downstream side of the intake pipe 5 is the cylinder head above the engine 1. 7 are connected to the intake ports 8 respectively. In addition, in the intake pipe 5,
The intake passage 9 is formed.

Fuel injector body 10 of fuel injector 6
Is attached on the intake pipe 5 at an angle so as to be directed to the engine 1 side. Further, a throttle valve 11 that regulates the flow rate of the inflowing air is provided in the intake passage 9 so as to be openable and closable.

FIG. 2 is a sectional view of the vicinity of the fuel injection device 6.

In FIG. 2, this fuel injection device body 10 is shown.
Is provided with a fuel introduction path 12 penetrating through the center thereof.
The rear end of the fuel introduction path 12 is a fuel introduction port 13, which is connected to a fuel pump (not shown). A plunger 14 is arranged near the center of the fuel introduction passage 12,
A solenoid coil 15 is wound around the outer circumference of the plunger 14. Further, a needle valve 16 that interlocks with the plunger 14 is arranged at the tip of the fuel introduction passage 12.

A fuel injection hole 17 is formed at the most distal end of the fuel injection device main body 10, and a diffusion nozzle 18 is formed in a mortar shape in front of the fuel injection hole 17 so as to expand in the fuel injection direction. It is provided.

An assist air chamber 19 is formed on the outer peripheral surface of the needle valve 16. The air in the assist air chamber 19 is guided from an assist air introducing passage 20 formed in the intake pipe 5, and the assist air intake port 21 of the introducing passage 20 is opened in the intake passage 9. To be done. The assist air intake port 21 is opened downstream of the throttle valve 11, and is closed at the upper end of the throttle valve 11 when the throttle valve 11 is in the "closed" position shown by the solid line in FIG. It is opened at a position where it can come off. The air in the assist air chamber 19 is ejected from the air nozzle 22 into the diffusion nozzle 18.

Reference numeral 23 is a wiring connector, which is connected to a controller (not shown).

Next, the operation of this embodiment will be described.

In FIG. 2, a sensor (not shown) detects conditions such as throttle opening, engine speed, engine temperature, outside air temperature and atmospheric pressure, and processes the information. Is applied. Solenoid coil 1 to which electric pulse is applied
5 generates a magnetic force to move the plunger 14 to the right in the figure. When the plunger 14 is moved to the right, the fuel previously pressurized by the fuel pump (not shown) is injected from the fuel injection hole 17 through the needle valve 16.

During normal operation of the engine 1, that is, the throttle valve 11 is "open" as shown by a broken line in FIG.
In the case of the position, at the same time as the fuel is injected, the air in the intake passage 9 is sucked into the assist air chamber 19 from the assist air intake port 21 through the assist air introduction passage 20 by the intake negative pressure of the engine 1. . The air in the assist air chamber 19 is ejected from the air nozzle 22 into the diffusion nozzle 18, mixed with the injected fuel and atomized, and then injected into the intake passage 9 of the engine intake system 3.

On the other hand, when the engine 1 is idling,
The throttle valve 11 is, for example, "closed" shown by a solid line in FIG.
In the position. Since the assist air intake port 21 is opened on the downstream side of the throttle valve 11 and is closed at the upper end of the throttle valve 11, a part of the intake negative pressure of the engine is taken in by the assist air. Therefore, the amount of air passing through the intake passage 9 does not decrease.

Since the amount of air passing through the intake passage 9 does not decrease, the throttle valve opening can be adjusted in a wider range, for example, from 0 ° to 1 ° 30 ', and the idling speed can be easily set. become. As a result, the rotation of the engine is stabilized, and in the multi-cylinder engine, the tuning of the rotation speed of each cylinder is facilitated.
Further, since the setting range of the throttle valve opening at the time of idling becomes wider, the amount of assist air at the time of idling to the fuel injection device can be set to an amount suitable for exhaust gas countermeasures.

[0029]

As described above, according to the fuel injection device of the present invention, assist air is mixed into the fuel directly injected into the intake passage of the engine to promote atomization of the fuel. In the above, while a throttle valve is provided in the intake passage, an intake port for assist air opened in the intake passage is provided downstream of the throttle valve, and an assist air taken in from the intake port is provided. Since the flow rate of is regulated by the throttle valve, it becomes easy to adjust the throttle valve opening during idling.

[Brief description of drawings]

FIG. 1 is a partial side view of an engine showing an embodiment of a fuel injection device according to the present invention.

FIG. 2 is a sectional view of the vicinity of a fuel injection device.

[Explanation of symbols]

 1 Engine 3 Intake System 4 Air Cleaner 5 Intake Pipe 6 Fuel Injector 9 Intake Passage 10 Fuel Injector Main Body 11 Throttle Valve 14 Plunger 15 Solenoid Coil 16 Needle Valve 17 Fuel Injection Hole 18 Diffusion Nozzle 19 Assist Air Chamber 20 Assist Air Inlet 21 Assist air intake 22 Air nozzle

Claims (2)

[Claims] 1. A fuel injection device for mixing assist air into fuel directly injected into an intake passage of an engine to promote atomization of the fuel, wherein a throttle valve is provided in the intake passage while the intake passage is provided. A fuel injection device characterized in that an intake port for assist air opened inside is provided on the downstream side of the throttle valve. 2. The fuel injection device according to claim 1, wherein the flow rate of the assist air taken in from the intake port is regulated by the throttle valve.