JPH06147060A - Fuel supply system of multicylinder internal combustion engine - Google Patents

Abstract

PURPOSE:To promote the atomization of fuel by means of exhaust in making the largest differential preddure between exhaust pipe internal pressure and an inlet pipe internal negative pressure act on an injection valve via an interconnecting passage by inducting the exhaust of a cylinder in an exhaust stroke into another cylinder where a fuel injection valve is installed, at a time when this cylinder is in an intake stroke. CONSTITUTION:A fuel injection valve 21 is provided with exhaust into an air inlet 22 at this downstream side from air inlet passages 23 (11 to 14), whereby fuel to be inducted out of a fuel inlet 1b is atomized. On the other hand, an exhaust extracting pipe 33 is installed in an exhaust passage 32, and thereby the exhaust is fed to the fuel injection valve 21 via four exhaust deriving passages 34 (D1 to D4). In this case, the exhaust of a cylinder in an exhaust stroke is inducted into the air inlet 22 of another cylinder in an intake stroke by these passages 34 and 23. Then the exhaust is mixed with the fuel and accelerated, thereby spraying it to an inlet valve opening part 10 from the fuel injection valve 21. With this constitution, utilizing the largest differential pressure between exhaust pipe internal pressure and inlet pipe internal negative pressure, fuel atomization by means of the exhaust is promoted.

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 4 and the suction negative pressure in the intake pipe 2 downstream of the throttle valve 4. However, it is a so-called air-assisted injection valve for atomizing the fuel introduced by the air through the fuel inlet 1b. The fuel injection valve 1 shown in this 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, up to the injection valve injection port portion 1c is a run-up section for the spray run-up section 1d is formed. Here, the injection amount and injection timing of the fuel are adjusted and controlled by the control unit 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 other words, depending on the operating region, there is a possibility that the fuel atomization level decreases, the mixture formation becomes insufficient, and combustion, fuel consumption, exhaust gas, etc. are impaired.

On the other hand, a passage is provided which connects the exhaust pipe of its own cylinder and the fuel injection valve provided in the intake pipe of the cylinder,
There is a technique in which the exhaust of the self-cylinder is introduced from the exhaust pipe of the self-cylinder and a part of the exhaust is used as air for atomization (see Japanese Utility Model Laid-Open No. 3-83376). However, in the case of using a part of the exhaust gas introduced from the exhaust pipe of the self-cylinder as the air for atomization, the exhaust pipe of the cylinder is almost equal to the atmospheric pressure at the timing of atomization, and Since there is no large pressure difference between the atmospheric pressure and the intake pressure, the effect of introducing the exhaust gas is low. On the other hand, at the timing when it is not necessary to perform atomization, that is, at the timing when injection is not performed, for example, the exhaust pressure becomes high in the exhaust stroke, so that there is a large differential pressure between the exhaust pressure and the intake pressure. Become. However, if the fuel injection is performed at the timing, the atomized fuel only adheres to the inner wall of the intake port to form a wall flow, which causes a problem that combustion, fuel consumption, exhaust gas, etc. are deteriorated.

The present invention has been made by paying attention to such a conventional problem, and in an internal combustion engine fuel supply apparatus for supplying air for atomizing fuel, the exhaust pressure of other cylinders in a high state. It is an object of the present invention to provide a fuel supply device for an internal combustion engine which has a simple structure and is capable of stably supplying fuel in various operating regions, thereby improving fuel efficiency and exhaust characteristics.

[0006]

Therefore, the present invention provides a fuel supply device for a multi-cylinder internal combustion engine having an air assist fuel injection valve for introducing gas from a gas introduction portion of the fuel injection valve to atomize the fuel, A gas introducing portion of the fuel injection valve and an exhaust pipe of a cylinder in the exhaust stroke when the cylinder in which the fuel injection valve is disposed are in the intake stroke are communicated with each other to introduce exhaust for atomizing the fuel. It is configured to have a passage.

[0007]

According to the above structure, when the cylinder in which the fuel injection valve is arranged is in the intake stroke, the exhaust gas flowing through the exhaust pipe of the cylinder in the exhaust stroke is injected through the communication passage. Introduced to the downstream side of the valve, fuel is mixed and accelerated with exhaust gas, atomized by a fuel injection valve, and injected.

Here, when a certain cylinder is in the exhaust stroke, the pressure in the exhaust pipe of the cylinder is higher than atmospheric pressure, so that the differential pressure from the negative pressure in the intake pipe of the cylinder in the intake stroke at that time is large. Become. That is, at the timing when the injection valve atomizes, a larger differential pressure acts on the fuel injection valve through the communication passage, and the fuel is actively atomized.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. The internal combustion engine according to the present embodiment is a 4-cylinder internal combustion engine,
FIG. 1 shows the intake passage 2 and the exhaust passage 32 associated with the # 1 cylinder. In the following description, the configuration associated with the # 1 cylinder will be described as a representative. The same components as those of the fuel injection valve 1 shown in FIG. 3 described in the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In the fuel injection valve 21 according to this embodiment,
Exhaust gas is introduced into an air inlet (gas introducing portion) 22 located on the downstream side of the fuel injection valve 21 via an air introducing passage 23 _I1 , and the atomization of the fuel introduced via the fuel inlet 1b is caused by the exhaust gas. Planned. Further, an exhaust extraction pipe 33 is arranged in the exhaust passage 32 of the cylinder, and the exhaust is supplied to the fuel injection valve via the exhaust derivation passage 34. In the present embodiment, the tip end opening portion 33a of the exhaust extraction pipe 33 is opened perpendicularly to the exhaust flow in the exhaust pipe 32. Incidentally, 31 is an exhaust valve, and 41 is a spark plug.

Further, as the structure according to the present invention, the air introduction passage 23 _I1 of the # 1 cylinder and the exhaust introduction passage 34 _D3 of the # 3 cylinder.
Similarly, the # 3 cylinder air introduction passage 23 _I3 and the # 4 cylinder exhaust derivation passage 34 _D4 , the # 4 cylinder air introduction passage 23 _I4 and the # 2 cylinder exhaust derivation passage 34 _D2. ,as well as#
Two cylinder air introduction passage 23 _I2 and # 1 cylinder exhaust passage 34
It is in communication with _D1 .

Here, in the internal combustion engine, ignition is performed in the order of # 1 cylinder, # 3 cylinder, # 4 cylinder and # 2 cylinder, so that the intake stroke, the exhaust stroke, etc. in each cylinder are as illustrated. As shown in 2. Next, the operation according to this embodiment will be described. At the fuel injection timing, the fuel injection valve 21 is controlled by the control unit 1e.

In this embodiment, the exhaust gas flowing through the exhaust pipe of the # 3 cylinder in the exhaust stroke via the exhaust outlet passage 34 _D3 and the air introduction passage 23 _I1 is arranged in the # 1 cylinder in the intake stroke. The fuel is introduced into the air inlet 22 of the fuel injection valve 21, mixed and accelerated with the exhaust gas, atomized by the fuel injection valve 21, and injected into the intake valve opening 10. That is, the exhaust outlet passage 34 _D3 and the air introduction passage 23 _I1 are provided with the air inlet 22 arranged downstream of the fuel injection valve 21 and the # 1 in which the fuel injection valve 21 is arranged.
This is a communication passage that introduces the exhaust gas for fuel atomization by communicating with the exhaust pipe of the # 3 cylinder in the exhaust stroke when the cylinder is in the intake stroke.

Here, when the # 3 cylinder is in the exhaust stroke, the exhaust pipe internal pressure of the # 3 cylinder is higher than the atmospheric pressure, and thus the intake pipe negative pressure in the # 1 cylinder which is in the intake stroke at that time. The differential pressure of becomes large. In the present embodiment, since the tip end opening portion 33a of the exhaust extraction pipe 33 is opened perpendicularly to the exhaust flow in the exhaust pipe 32, the exhaust extraction pipe 33 concerned.
The total pressure of the exhaust gas is applied to the exhaust gas, and the exhaust gas can be taken out with the highest pressure.

That is, in this way, the highest exhaust pressure
Exhaust gas in a bad state is on the downstream side of the fuel injection valve 21 in the # 1 cylinder.
Is introduced into the air inlet 22 of. That is, the injection valve 21 is fine
A larger differential pressure is applied to the exhaust
Exit 34_D3And air introduction passage 23 _I1Through the fuel injector 21
It will affect the pressure state of the intake pipe 2 too much.
Stable and independent supply of atomizing air to the fuel injection valve 21
And the active atomization of fuel is performed.
It

Further, the same action and effect can be obtained also in the fuel injection valve provided in the other cylinder. As a result, the fuel spray can be atomized regardless of the engine operating state, and the spray does not adhere to the inner wall of the intake port as a wall flow and is sufficiently mixed with air and flows into the combustion chamber. It has become possible to prevent the formation of fuel wall flow in the air and to increase the space floating rate of fuel. 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, even when the throttle valve is close to full opening even under a high load, the differential pressure between the suction negative pressure and the exhaust pressure is reduced, so that the supply of assist air is reduced.
In the operating region, since the throttle valve is close to full opening, the flow velocity of intake air is high, so it is unnecessary to atomize the fuel. That is, exhaust gas can be recirculated at a predetermined timing without using any control means, assist air is supplied at a necessary timing with a simple structure, and residual gas that is unstable to combustion when unnecessary It is possible to suppress the decrease in the charging efficiency during the fully open operation to the minimum necessary without increasing the ratio.

[0018]

As described above, according to the present invention, the gas introduction portion of the fuel injection valve and the cylinder in the exhaust stroke when the cylinder in which the fuel injection valve is disposed are in the intake stroke. Since the exhaust pipe and the communication passage for introducing the exhaust gas for atomizing the fuel are provided in communication with each other, the simple structure is maintained.
Only at the timing when the injection valve atomizes, a larger differential pressure acts on the injection valve through the communication passage, so that the atomization air is stably supplied without depending on the pressure state in the intake pipe. As a result, active atomization of the fuel is performed, formation of the fuel wall flow in the combustion chamber is prevented, the space floating rate of the fuel is increased, and stable combustion is always performed. It also has the effect of improving fuel efficiency and exhaust performance.

[Brief description of drawings]

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

FIG. 2 is a time chart of the combustion stroke in the above embodiment.

FIG. 3 is a vertical cross-sectional view showing the configuration of a conventional fuel supply device.

[Explanation of symbols]

 2 Intake pipe 4 Throttle valve 21 Fuel injection valve 22 Air inlet 23 Air introduction passage 32 Exhaust passage 33 Exhaust extraction pipe 34 Exhaust outlet passage

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display area F02M 29/00 G 69/04 G 7825-3G

Claims (1)

[Claims] 1. A fuel supply device for a multi-cylinder internal combustion engine having an air-assisted fuel injection valve for introducing gas from a gas introduction part of a fuel injection valve to atomize the fuel. An internal combustion chamber characterized in that a communication passage communicating with an exhaust pipe of a cylinder in the exhaust stroke when the cylinder in which the fuel injection valve is arranged is in the intake stroke is provided to introduce the exhaust gas for fuel atomization. Engine fuel supply system.