JPH0526134A - Fuel injector - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Improvement of operating performance, fuel economy, and service life of compressed air pump in the middle and high opening range of throttle valve and during sudden acceleration operation of engine. Of a fuel injection device aiming at the above. [Structure] In the intake passage 2A downstream of the throttle valve 4,
The upstream side is closed and the downstream side is opened, and the downstream side opening is provided with the fuel injection passage 6 provided with the enlarged slope portion 6C whose inner diameter portion is temporarily enlarged toward the downstream side of the intake passage 2A, and the fuel injection. An injection valve injection passage 7 that opens in the fuel injection passage 6 in order to inject and supply fuel injected from the valve 5 into the fuel injection passage 6.
And a first air passage 8 whose one end opens into the intake passage 2B on the upstream side of the atmosphere or the throttle valve 4 and whose other end opens into the injection valve injection passage 7; Tank 1
A second air passage 10 that is connected to a surge tank 12 of a compressed air pump 11 that pumps when the pressure in 2 is below a certain pressure and stops the pumping when the pressure is above a certain pressure, and the other end of which is connected to a first air passage 8. To provide.

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 for injecting fuel pressurized by a fuel pump into an intake passage through a fuel injection valve, and particularly to an intake passage downstream of a throttle valve. The present invention relates to a fuel injection device in which fuel is injected from a fuel injection valve and the fuel is supplied to an intake pipe connected to a cylinder of an engine.

[0002]

2. Description of the Related Art There is Japanese Patent Application No. 2-275640 filed by the applicant of the present invention as a fuel injection device having excellent atomization characteristics and uniformity of fuel injected into an intake passage.

According to the fuel injection device, the longitudinal axis XX of the intake passage is in the intake passage downstream of the throttle valve.
The fuel injection is provided substantially parallel to, the upstream side is closed and the downstream side is opened, and the downstream opening is provided with an enlarged inclined portion whose inner diameter portion is temporarily enlarged toward the downstream side of the intake passage. Passage, an injection valve injection passage that opens in the fuel injection passage for injecting and supplying fuel injected from the fuel injection valve into the fuel injection passage, and one end that opens in the intake passage upstream of the atmosphere or the throttle valve. However, the other end is arranged at least in the air passage whose opening is in the injection valve injection passage and in the enlarged slope portion of the fuel injection passage, and together with the enlarged slope portion, the longitudinal axis Y of the fuel injection passage is formed.
And a cone member having an enlarged slanted protrusion that forms a continuous annular gap along -Y.

According to such a conventional fuel injection device, the fuel injected from the fuel injection valve is injected toward the cone member in the fuel injection passage through the injection valve injection passage, and at this time, the fuel is injected through the injection valve injection passage. The air in the intake passage upstream of the atmosphere or the throttle valve flows into the flowing fuel through the air passage, the fuel and air are mixed in the injection valve injection passage, and the fuel containing this air is injected into the injection valve injection passage. The fuel is injected toward the cone member in the fuel injection path.

Fuel containing air that has collided with the cone member is
With a high injection velocity, the fuel including the atomized air dispersed in the annular gap formed between the enlarged inclined portion of the fuel injection passage and the enlarged inclined protrusion of the cone member is discharged to the outlet of the fuel injection passage. It flows down and is injected from the outlet on the downstream side of the fuel injection path into the intake path.

In the fuel containing air flowing down the annular gap, the annular gap is formed with a relatively small volume (small gap), the flow velocity of the fuel containing air does not decrease, and further, the annular gap is on the downstream side. By forming continuously toward the opening of, it is possible to form a reliable annular fuel foam,
This annularly formed fuel containing air can be injected from the end of the fuel injection passage toward the intake passage while expanding.

[0007]

The conventional fuel injection device has the following problems to be solved. That is, the flow of air that flows down from the atmosphere at the inlet of the air passage or the intake passage upstream of the throttle valve toward the inside of the injection valve injection passage at the outlet of the air passage is the inlet of the air passage. Caused by the pressure difference between the pressure applied to the air passage and the pressure applied to the outlet of the air passage. (It depends on the pressure difference.)

Here, considering the pressure condition at the outlet of the air passage, the outlet of the air passage is opened in the injection valve injection passage, while the injection valve injection passage is provided downstream of the throttle valve via the annular gap ( Since it is open to the intake passage on the engine side, the pressure at the outlet of the air passage is approximately the same as the pressure in the intake passage downstream of the throttle valve.

Here, looking at the pressure state in the intake passage downstream of the throttle valve, the negative pressure is large (the absolute value of the negative pressure is large) in the low opening range of the throttle valve, and the throttle valve opens low. The negative pressure becomes small in the middle opening range and the high opening range, which are opened more than 10 degrees. (The absolute value of negative pressure becomes small)

From the above, when the throttle valve opening is equal to or larger than the middle opening range of the throttle valve, the pressure at the inlet of the air passage is maintained at about atmospheric pressure, but in the intake passage downstream of the throttle valve. The negative pressure at the outlet of the air passage decreases due to the decrease in the negative pressure of the air passage, which reduces the differential pressure between the inlet and the outlet of the air passage, which reduces the amount of air flowing in the air passage. Air velocity tends to slow down.

Thus, due to the decrease in the amount of air supplied from the air passage into the injection valve injection passage and the decrease in the air flow velocity, the fuel injected into the injection valve injection passage and the air supplied from the air passage are There is a risk that good mixing and atomized state may not be formed due to the obstruction of the mixing of the air-fuel mixture, and a large amount of tests are performed to improve the operating performance of the engine, such as distributing the air-fuel mixture to the cylinders, improving the engine output and stabilizing the engine rotation. This requires a lot of man-hours, and since the fuel is likely to adhere to the intake pipe wall, the fuel economy may be deteriorated. Therefore, many test man-hours are required to improve the fuel economy. For example, the inclination angle of the enlarged sloping portion, the gap of the annular gap, and the like are selected.

Further, considering the rapid acceleration operation of the engine in which the throttle valve is rapidly opened from the low opening range to the high opening range, the intake air which is maintained at a large negative pressure in the low opening range of the throttle valve is considered. The pressure in the passage is instantly reduced with the shift of the throttle valve to the high opening range, the negative pressure becomes small, and the differential pressure between the inlet and the outlet of the air passage is reduced. The air flow velocity decreases as the amount of air flowing inside decreases.

Therefore, mixed atomization of the fuel and the air injected and supplied into the fuel injection path through the injection valve injection path is hindered, and a lot of test man-hours are required to obtain good acceleration performance. It was

The fuel injection device according to the present invention is intended to improve the operating performance of the engine, particularly in the high opening region of the throttle valve, the rapid acceleration operating performance of the engine, and the fuel economy. The main purpose is.

[0015]

In order to achieve the above object, a fuel injection system according to the present invention is an internal combustion engine for supplying fuel injected from a fuel injection valve to an engine through an intake passage downstream of a throttle valve. In the fuel injection device in the above, in the intake passage downstream of the throttle valve, the longitudinal axis X- of the intake passage is taken.
A fuel that is substantially parallel to X, has an upstream side closed and a downstream side opened, and an enlarged inclined portion whose inner diameter portion is temporarily enlarged toward the downstream side of the intake passage is provided in the downstream opening. An injection path, an injection valve injection path that opens into the fuel injection path for injecting and supplying fuel injected from the fuel injection valve into the fuel injection path, and an intake path whose one end is upstream of the atmosphere or the throttle valve Is disposed in at least the enlarged inclined portion of the fuel injection passage and the first air passage whose other end is opened in the injection valve injection passage, and together with the enlarged inclination portion, the longitudinal axis Y-Y of the fuel injection passage. A cone member having an enlarged sloped projection forming a continuous annular gap along the second air passage, one end connected to the surge tank, the other end connected to the first air passage or the injection valve injection passage, and the surge It is connected to the tank and the pressure inside the surge tank is constant No pumping action below, a compressed air pump to stop pumping at least a certain positive pressure, second
An opening / closing valve that opens and closes the air passage, opens the second air passage when the negative pressure in the intake passage downstream of the throttle valve is equal to or lower than a certain negative pressure, and closes the second air passage when the negative pressure is equal to or more than the certain negative pressure. .

According to the fuel injection device configured as described above, the compressed air is supplied from the compressed air pump into the surge tank, and the compressed air having a certain positive pressure or higher is always stored therein. When the negative pressure in the intake passage on the engine side of the throttle valve becomes small in the middle and high opening range of the throttle valve and during rapid acceleration operation of the engine, the on-off valve opens the second air passage and opens the surge tank from the surge tank. The forcedly pressurized air is supplied into the first air passage or the injection valve injection passage via the two air passages.

The fuel injected from the fuel injection valve is injected toward the cone member in the fuel injection path through the injection valve injection path, and at this time, in the fuel flowing through the injection valve injection path, or the first
The compressed air is forcibly supplied to the air passage from the second air passage.

Therefore, the fuel and the air are mixed well in the injection valve injection path, and the fuel containing the air is injected from the injection valve injection path toward the cone member in the fuel injection path.

The fuel containing air that has collided with the cone member is
With a high injection velocity, the fuel including the atomized air dispersed in the annular gap formed between the enlarged inclined portion of the fuel injection passage and the enlarged inclined protrusion of the cone member, the fuel including the atomized air is discharged from the outlet of the fuel injection passage. And flows toward the inside of the intake passage from the outlet on the downstream side of the fuel injection passage.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the fuel injection device according to the present invention will be described below with reference to FIG. In the description, the upper, lower, left, and right sides are as shown in the drawings and are not limited to this.

Reference numeral 1 denotes a throttle valve main body having an intake passage 2 penetrating downward from above in FIG. 1, and attached to a throttle valve shaft 3 rotatably supported by the throttle valve main body 1 in the intake passage 2. The throttle valve 4 is arranged, and the throttle valve 4 controls the intake passage 2 to open and close.

5 is an ECU (Electronic Control Unit)
When a current flows through the solenoid coil due to a signal from (not shown), the core is attracted and the needle valve integral with the core is attracted until the flange of the needle valve hits the spacer, and the valve is fully opened. It is a known fuel injection valve that injects pressurized fuel from its tip.
(The description of the internal structure of the fuel injection valve is omitted.)

Reference numeral 6 is a fuel injection passage provided in the intake passage 2 of the throttle valve body 1 and is constructed as follows. That is, the fuel injection passage 6 has a circular cross section, is located in the intake passage 2A on the downstream side (lower engine side in FIG. 1) of the throttle valve 3, and has a longitudinal axis line of the fuel injection passage 6. YY is parallel to the longitudinal axis XX of the intake passage 2 (in this example, Y-
(Y and XX are on the same line), and the upstream side thereof is the closed end 6
It is blocked at A, and the downstream side opens toward the lower side of the intake passage 2 (engine side) through the opening end portion 6B.

Then, the inner diameter of the fuel injection passage 6 is temporarily reduced toward the opening end portion 6B on the downstream side from the expansion starting point A (between the closed end portion 6A of the fuel injection passage 6 and the opening end portion 6B). An enlarged sloped portion 6C is provided to enlarge.

The enlarged inclined portion 6C is such that the inner diameter thereof is continuously enlarged along the longitudinal axis Y--Y of the fuel injection passage 6, and its inclination is linear or curved. Also,
It may be stepwise. However, its inner diameter is enlarged and must not be reduced (funnel-shaped). FIG. 1 shows a linear enlarged slope portion 6C.

Reference numeral 7 denotes an injection valve injection passage for injecting fuel injected from the fuel injection valve 5 into the fuel injection passage 6.
One end of the injection valve injection passage 7 is connected to the injection port of the fuel injection valve 5, and the other end opens into the fuel injection passage 6.

The longitudinal axis Z1-Z2 along the fuel flow in the injection valve injection path 7 opens toward the longitudinal axis Y-Y of the fuel injection path 6 and, in this example, the enlarged starting point A. The fuel injection passage 6D on the upstream side is opened.

Reference numeral 8 is a first air passage, one end of which opens into the intake passage 2B upstream of the throttle valve 3 and the other end of which opens into the injection valve injection passage 7. One end of this first air passage 8 is shown. May be open to the atmosphere.

The fuel injection path 6 is provided in the fuel injection path 6.
A cone member 9 is arranged which forms an annular gap with the inner diameter of the cone member.

The cone member 9 is arranged in the enlarged inclined portion 6C of the fuel injection passage 6, and has an enlarged inclined projection 9A having an enlarged portion continuous toward the downstream side, and a cross section upstream from the enlargement starting point A. And a cylindrical portion 9B arranged in the circular fuel injection passage 6D, the fuel injection passage 6D on the upstream side of the expansion starting point A and the cylindrical portion 9B of the cone member 9,
Further, the enlarged inclined portion 6C of the fuel injection path 6 and the enlarged inclined protrusion 9A of the cone member 9 form a continuous annular gap S from the upper side to the lower side.

Thus, at the open end 6B of the fuel injection passage 6, the annular gap S opens downward. The annular gap S is preferably about 1 mm, but is not limited to this value and may be set appropriately.

Reference numeral 10 is a second air passage provided separately from the first air passage 8. One end 10A on the upstream side of the second air passage 11 is connected to the surge tank 12 and the other end 1 on the downstream side.
0B is connected to the first air passage 8 and opens. The other end 10B on the downstream side may be directly opened into the injection valve injection passage 7.

Reference numeral 11 is a known compressed air pump having a motor and the like as a drive source and a vane, a gear, a piston and the like as a pump portion. Compressed air generated in the compressed air pump 11 is supplied to a surge tank 12. It

The compressed air pump 11 is driven when the pressure in the surge tank 12 is below a certain positive pressure (for example, less than 1.6 Kg / Cm2) and is above a certain positive pressure (for example, 1.6 kg / Cm2).
The drive of the pump stops at Kg / Cm2 or more).

A pressure sensing switch 13 senses the pressure in the surge tank 12 and outputs an electric signal to the compressed air pump 11. The pressure sensing switch 13 outputs an OFF signal above a certain positive pressure and turns it on below a certain positive pressure. It outputs a signal,
As a result, the drive of the compressed air pump 11 is controlled according to the pressure in the surge tank 12. That is, compressed air having a certain positive pressure or higher is always stored in the surge tank 12.

Reference numeral 14 is a surge tank 12 and a second air passage 1
0 is an on-off valve which is arranged between the other end 10B on the downstream side of 0 and opens and closes the second air passage 10, and the negative pressure in the intake passage 2A on the downstream side (engine side) of the throttle valve 4 is constant negative. The second air passage 10 is opened when the pressure becomes equal to or lower than the pressure (the absolute value of the negative pressure becomes small), and the second air passage 10 is closed when the pressure becomes equal to or higher than a certain negative pressure (the absolute value of the negative pressure becomes large).

More specifically, one example will be described. The pressure in the intake passage 2A on the engine side of the throttle valve 4 is -35.
When the pressure becomes 0 mmHg or less, the ON signal is output toward the on-off valve 14 from the pressure sensor that converts the pressure (not shown below to atmospheric pressure) to an electric signal to drive the on-off valve 14. 2 The air passage 10 is opened, and the pressure in the intake passage 2A on the engine side of the throttle valve 4 is -350 mm.
When the pressure becomes higher than Hg, an OFF signal is output from the pressure sensor to the on-off valve 14, and the on-off valve 14 becomes the second air passage 1
Block 0.

Reference numeral 15 denotes a one-way control valve provided in the first air passage 8, which opens the first air passage 8 when the pressure in the first air passage 8 is a negative pressure, and the pressure in the first air passage 8 is increased. Closes the first air passage 8 in the positive pressure state.

As an example of the one-way control valve 15, a valve seat 15A is formed toward the inflow side of the first air passage 8, and a valve 15C pressed by a spring 15B is arranged on the valve seat 15A.

According to this, when the pressure in the first air passage 8 is in the negative pressure state, the valve 15C receives this negative pressure and opens the valve seat 15A against the pressing force of the spring 15B. When the pressure in the first air passage 8 is in the positive pressure state, the valve 15
C is the valve seat 1 due to the positive pressure and the pressing force of the spring 15B.
Block 5C.

During operation of the engine, the inside of the intake passage 2 is in a negative pressure state, and this negative pressure acts on the first air passage 8. Therefore, the one-way control valve 15 in the first air passage 8 is kept open. It

Next, the operation will be described. During operation of the engine, the pressure in the surge tank 12 is always maintained at a substantially constant positive pressure (for example, 1.6 Kg / Cm2). This is because when the pressure in the surge tank 12 is below a certain positive pressure (for example, 1.6 Kg / Cm2), the pressure sensing switch 13 senses the pressure in the surge tank 12 and sends an ON signal to the compressed air pump 11. When the pressure in the surge tank 12 rises above a certain positive pressure, the pressure switch 13 outputs an OFF signal to the compressed air pump 11. This is because the compressed air pump 11 is stopped from being driven. First, the operation of the throttle valve 4 in the low opening range will be described. During such operation, the intake passage 2A downstream of the throttle valve 4 has a temperature of -350 m.
A large negative pressure of mHg or more is generated. According to this, the pressure sensor outputs an OFF signal to the opening / closing valve 14, and the opening / closing valve 14 holds the second air passage 10 in the closed state. The pressurized air is not supplied from 11 into the first air passage 8.

On the other hand, a large negative pressure in the intake passage 2A acts on the first air passage 8 through the annular gap S and the injection valve injection passage 7. According to this, the amount is more than that of the first air passage 8. Air having a high flow velocity is sucked into the injection valve injection passage 7.

One-way control valve 1 arranged in the first air passage 8
5 is a negative pressure in the first air passage 8 so that the valve 15C has a valve seat 15A.
Is opened to allow the air flow in the first air passage 8.

The air sucked into the injection valve injection passage 7 is mixed well with the fuel injected from the fuel injection valve 5 into the injection valve injection passage 7 to form a mixture, which is the injection valve. The fuel is injected into the fuel injection path 6D on the upstream side above the expansion starting point A from the injection path 7.

The fuel containing air injected into the fuel injection path 6D collides with the cylindrical portion 9B of the cone member 9 at a high speed, and the fuel is further finely scattered by the collision, and the cylindrical portion 9B. Disperses finely over the entire circumference of.

This is because the annular gap S formed by the fuel injection passage 6D on the upstream side of the enlargement starting point A and the cylindrical portion 9B of the cone member 9 is minutely formed (held in a small volume). This is achieved by not slowing down the velocity of the fuel.

Then, the fuel containing finely dispersed air having a high velocity in the annular gap S of the cylindrical portion 9B of the cone member 9 and the fuel injection passage 6D on the upstream side of the expansion starting point A is the cone member 9B. 9A, 9A, and the fuel injection path 6
In the annular gap S formed by the enlarged sloping portion 6 </ b> C and flowing down along the inclined annular gap.

This is because the decrease in the flow velocity of the fuel containing dispersed air can be suppressed by the minute annular gap, and the inclined annular gap is defined by the longitudinal axis Y--Y of the fuel injection passage 6. It is achieved by controlling the flow direction of the fuel including air by continuously forming the fuel cells along the flow direction.

Then, the fuel mixed with the air is injected with a complete annular spray shape evenly dispersed in the intake passage 2A through the annular gap S formed at the open end 6B of the fuel injection passage 6. It

Next, a description will be given of the operation in which the throttle valve 4 is opened in the altitude range from the low opening range of the throttle valve 4 to the operation range. In the operation, the intake passage 2A downstream of the throttle valve 4 is operated. The negative pressure is lower than the negative pressure in the low opening range of the throttle valve 4 and is −350 mmHg or less (approaching atmospheric pressure).

According to this, the pressure sensor has the opening / closing valve 14
The ON / OFF valve 14 outputs the ON signal toward
The air passage 10 is opened so that the surge tank 12
Compressed air having a certain positive pressure or higher that has been stored therein is injected from the second air passage 10 toward the first air passage 8.

The pressurized air is mixed well with the fuel flowing in the injection valve injection passage 7, and this mixture is injected into the intake passage 2A through the annular gap S as described above.

That is, in the middle of the throttle valve 4, the negative pressure in the intake passage 2A on the downstream side becomes a small negative pressure of -350 mmHg or less in the high opening range, and this negative pressure causes the injection valve from the first air passage 8 to inject. Even if the intake of air into the injection passage 7 is reduced, the amount of air is reduced, the flow velocity of air is reduced, and a phenomenon occurs,
Since the air pressurized from the air passage 11 is forcibly supplied into the injection valve injection passage 7, a good mixed state of air and fuel is still obtained in the injection valve injection passage 7, The distribution of the air-fuel mixture to the engine, the output performance of the engine, the stability of rotation, and the fuel economy were maintained well. Note that the change point of the ON-OFF signal from the pressure sensor is set to -350 mm, but this value is not limited to this value as long as the optimum negative pressure value can be determined depending on the compatibility with the engine.

Further, the one-way control valve 15 arranged in the first air passage 8 may be provided if the pressurized air supplied from the second air passage 10 does not leak from the inlet side of the first air passage 8 in a large amount. Good. This is determined by a conformance test with the agency.

Next, a description will be given of a rapid acceleration operation of the engine in which the throttle valve 4 is rapidly opened from the low opening range to the high opening range. In the low opening range of the throttle valve 4, a large negative pressure of −350 mmHg or more is generated in the intake passage 2A on the downstream side of the throttle valve 4. According to this, as described above, the pressure sensor outputs The open / close valve 14 is set to the second position by the OFF signal.
Although the pressurized air is not supplied to the first air passage 8 by keeping the air passage 10 closed, the throttle valve 4
Due to the large negative pressure in the intake passage 2A on the further downstream side, air having a sufficient amount and a high flow velocity flows in the first air passage 8, and this air is supplied into the injection valve injection passage 7 and is injected into the injection valve injection passage 7. Good mixing and atomization of fuel and air in 7 are maintained.

Then, when the throttle valve 4 is rapidly opened from the low opening range of the throttle valve 4 to the middle and high opening ranges to rapidly accelerate the engine, the negative pressure in the intake passage 2A downstream of the throttle valve 4 is increased. Is instantly reduced to -350 mmHg or less.

According to this negative pressure change, the pressure sensor immediately outputs an ON signal to the opening / closing valve 14, thereby opening the second air passage 10, and applying the pressure in the surge tank 12 from the second air passage 10. The compressed electricity is supplied into the injection valve injection passage 7.

Although compressed air is supplied from the second air passage 10 into the injection valve injection passage 7, although the amount of air flowing through the first air passage 8 is reduced and the air flow velocity is reduced, The fuel and air are sufficiently mixed and atomized in the injection valve injection passage 7, and the acceleration performance can be remarkably improved.

[0060]

According to the present invention, in the middle and high opening range of the throttle valve, the on-off valve of the second air passage is opened and the compressed air in the surge tank is introduced into the injection valve injection passage through the second air passage. Since the fuel is forcibly supplied, the fuel and air are sufficiently mixed in the injection valve injection passage to obtain a good atomization state, the mixture is distributed to the cylinders, and the output of the engine is improved.
The degree of freedom in tests for improving engine performance, such as stability of rotation, increases, and performance improvement can be easily achieved.

The compressed air pump stops driving when the pressure in the surge tank is raised to a certain positive pressure, and is driven when the pressure drops below a certain positive pressure, so that the movement time of the compressed air pump is greatly shortened. It was made, and the service life was greatly improved.

In addition, since the pressurized air of a certain positive pressure or more is always stored in the surge tank, it is possible to supply the pressurized air without delay in the opening operation of the on-off valve, which has particularly high acceleration performance. I was able to improve.

When the throttle valve is opened to a high opening degree and the negative pressure in the intake passage becomes small during the rapid acceleration operation of the engine, the pressurized air stored in the surge tank in the injection valve injection passage is compressed. Since it was forcibly supplied, the mixing and atomization state in the injection valve injection passage was improved and the acceleration performance could be improved as in the above case.

Further, in the first air passage, the first air passage is opened when the pressure in the first air passage is negative, and the first air passage is closed when the pressure in the first air passage is positive. According to the arrangement of the one-way control valve, when the pressurized air is supplied from the surge tank into the second air passage, there is no leakage of air from the first air passage to the atmosphere side. Since the air can be sufficiently supplied into the injection valve injection passage, the mixing property of the air and the fuel in the injection valve injection passage is improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing an embodiment of a fuel injection device of the present invention.

[Explanation of symbols]

2 intake passage 2A intake passage downstream of throttle valve 4 Throttle valve 5 Fuel injection valve 6 Fuel injection path 7 injection valve injection path 8 First air passage 9 Cone member 10 Second air passage 11 Compressed air pump 12 surge tank 14 on-off valve

Claims (2)

[Claims] 1. A fuel injection device for an internal combustion engine, which supplies fuel injected from a fuel injection valve to an engine through an intake passage downstream of a throttle valve, wherein the intake passage is downstream of the throttle valve, It is substantially parallel to the longitudinal axis X-X of the intake passage, its upstream side is closed and its downstream side is open, and its downstream side opening has an inner diameter part that is directed toward the downstream side of the intake passage. A fuel injection path having an enlarged sloping portion that expands next, an injection valve injection path that opens into the fuel injection path to inject and supply fuel injected from the fuel injection valve into the fuel injection path, and one end to the atmosphere. Or a first air passage opening in the intake passage upstream of the throttle valve and the other end opening in the injection valve injection passage,
A cone member provided with at least the enlarged sloped portion of the fuel injection passage, and the enlarged sloped protrusion portion forming a continuous annular gap along the longitudinal axis Y-Y of the fuel injection passage together with the enlarged slope portion; One end is connected to the surge tank, the other end is connected to the second air passage that is connected to the first air passage or the injection valve injection passage, and the surge tank, and the pressure in the surge tank is constant below a certain positive pressure and acts as a pump. The compressed air pump that stops pumping at a positive pressure or more and the second air passage are opened and closed, and the second air passage is opened and kept constant when the negative pressure in the intake passage downstream of the throttle valve is less than a certain negative pressure. An on-off valve that closes the second air passage at a negative pressure or higher. 2. The first air passage is opened to the first air passage when the pressure in the first air passage is negative.
2. The fuel injection device according to claim 1, further comprising a one-way control valve that closes the first air passage when the pressure in the air passage is positive.