JPH05231276A - Air intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide an air intake device which prevents adhesion of fuel to an swirl control valve (SCV) even when a fuel injection valve is disposed in a place situated upstream from the SCV. CONSTITUTION:An air intake device for an internal combustion engine comprises first and second air intake ports 6 and 7, an SCV 12 having a notch part 15 formed in a portion facing the first air intake port 6, a first fuel injection valve 17 for injecting fuel toward the interior of the first air intake port 6 in a state to point to the notch part 15 from a place situated upstream from the SCV 12, and a second fuel injection valve 18 disposed upstream from the SCV 12 in a state to point approximately to the air intake port 7 and injecting fuel in a direction in which the fuel is collided with fuel injected from the first fuel injection valve 17. During closing of the SCV 12, fuel is injected from the first fuel injection valve 17 and during opening of the SCV 12, fuel is injected from both the first and second fuel injection valves 17 and 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake system for an internal combustion engine, and more particularly to an intake system for an internal combustion engine having a swirl control valve for generating a swirl flow in a combustion chamber.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 6, a first intake port 32 and a second intake port 33 branching from an intake passage 30 and communicating with a combustion chamber 31 of an engine, a first intake port 32 and a second intake port. An intake device for an internal combustion engine is known, which includes a swirl control valve 35 having a notch 34 in a portion facing the first intake port 32, the swirl control valve 35 being disposed close to a partition upstream end 36 of each port 33. (Actual Kaihei 1-
(See No. 127934).

[0003]

By the way, in order to obtain a strong swirl flow in the combustion chamber, it is necessary to bring the swirl control valve as close to the combustion chamber side as possible. In this case, the fuel should be provided downstream of the swirl control valve. Since there is not enough space for disposing the injection valve, the fuel injection valve must be disposed upstream of the swirl control valve.

However, if the fuel injection valve is arranged upstream of the swirl control valve, the fuel injection direction of the fuel injection valve is fixed in a certain direction, and therefore there are many cases when the swirl control valve is closed. Fuel adheres to the swirl control valve to form a wall flow,
As a result, there are cases in which problems such as an increase in the amount of HC discharged, deterioration of drivability due to a delay in fuel transportation, and difficulty in air-fuel ratio control may occur.

Incidentally, it is apt to think that the fuel adhesion to the swirl control valve can be prevented only by disposing the fuel injection valve so as to be directed to the cutout portion of the swirl control valve. Since the fuel distribution to the first intake port and the second intake port is unbalanced at the time of opening, it is not possible to ensure a uniform air-fuel mixture in the combustion chamber. For example, when the air-fuel mixture near the spark plug is rich, NOx increases. However, if it is thin, there is a problem such as misfire and deterioration of drivability.

The present invention has been made in view of the above problems, and the swirl control valve is brought closer to the combustion chamber side in order to obtain a strong swirl flow in the combustion chamber. Even if the fuel injection valve is arranged on the upstream side of the above, it is an object of the present invention to provide an intake system for an internal combustion engine that can prevent fuel from adhering to the swirl control valve.

[0007]

In order to solve the above problems, the present invention provides a first intake port and a second intake port that branch from an intake passage and communicate with a combustion chamber of an engine, and a first intake port and A swirl control valve having a notch at a portion facing the first intake port, the swirl control valve being disposed so as to be able to open and close the intake passage in the vicinity of the upstream ends of the partition walls of the second intake ports. Of the first fuel injection valve for injecting fuel into the first intake port by directing the cutout portion from the upstream side thereof, and the second intake port is disposed substantially upstream of the swirl control valve toward the second intake port. And a second fuel injection valve for injecting fuel so as to collide with the fuel injected from the first fuel injection valve, and when the swirl control valve is closed, the fuel injection from the first fuel injection valve is performed. There, at the time of opening the swirl control valve performs fuel injection from both the first fuel injection valve and the second fuel injection valve, characterized in that.

[0008]

In order to obtain a strong swirl flow in the combustion chamber, it is necessary to dispose the swirl control valve closer to the combustion chamber. In this case, the fuel injection valve is disposed downstream of the swirl control valve. However, according to the above configuration, even if the fuel injection valve is arranged on the upstream side of the swirl control valve, it is possible to prevent fuel from adhering to the swirl control valve, and moreover, when the swirl control valve is opened. , A uniform air-fuel mixture can be supplied to both the first intake port and the second intake port.

That is, in the closed state of the swirl control valve, fuel is injected from the first fuel injection valve toward the cutout portion of the swirl control valve, and the main part of the injected fuel adheres to the swirl control valve. Without being guided to the first intake port,
The flow velocity at the notch portion where the air-fuel mixture introduced into the combustion chamber passes in a concentrated manner is high, and atomization of the fuel is achieved.
Therefore, the main portion of the fuel injected from the first fuel injection valve is atomized without becoming a wall flow, and a strong swirl flow is generated in the combustion chamber due to the air-fuel mixture in which fuel atomization is promoted. ..

On the other hand, in the open state of the swirl control valve, fuel is injected from both the first fuel injection valve and the second fuel injection valve, and the fuel injected from both collides with each other and atomizes. When the fuel injected is first
It is distributed and introduced into both the intake port and the second intake port.
For this reason, a good mixture can be introduced into the combustion chamber, the combustion state can be improved, and the emission of HC can be reduced, and the vehicle speed does not increase even though the accelerator is stepped on when starting or accelerating. It is possible to prevent hesitation and improper acceleration, that is, stumble, that accompanies a decrease in output that occurs during acceleration.

That is, the optimum mixture is introduced into the combustion chamber of the engine in accordance with the opening / closing of the swirl control valve, and the exhaust gas can be cleaned and the drivability can be improved.

[0012]

Embodiments of the present invention will be described below with reference to FIGS. Reference numeral 1 is a cylinder block that forms the cylinder 2, and 3 is a cylinder head that covers the upper portion of the cylinder block 1.

The cylinder head 3 is formed with a first intake port 6 and a second intake port 7 branching from the intake passage 4 and communicating with the combustion chamber 5, and these first intake port 6 and second intake port 6 are formed.
The intake port 7 is provided with a first intake valve 8 and a second intake valve 9 that face the combustion chamber 5 and open and close each of these ports.

An intake manifold 10 is disposed on a side portion of the cylinder head 3 to form an intake passage 4, and an upstream side of the intake passage 8 is provided with an air cleaner or an intake cleaner for cleaning intake air, though not shown. A throttle valve and the like for adjusting the amount of air are provided.

The first intake port 6 and the second intake port 7 are partitioned by a partition wall 11, and a swirl control valve 12 having a substantially elliptical shape has an intake passage having a substantially elliptical cross section in the vicinity of its upstream end 11a. 4 is arranged so that it can be opened and closed.

The swirl control valve 12 arranged in the intake passage 4 is fastened with two screws 14 to a shaft 13 rotatably arranged in the cylinder head 3 defining the intake passage 4, A cutout portion 15 is formed in a portion facing the intake port 6. As shown in the drawing, the cutout portion 15 is formed on the first intake port 6 side as well as the upper half portion 4a of the intake passage 4, and the remaining upper half portion of the swirl control valve 12 and the cutout portion 15 are separated from each other. It is defined by an arc 16.

A first fuel injection valve 17 and a second fuel injection valve 18 are provided on the upstream side of the swirl control valve 12, that is, on the intake manifold 10, and these can independently inject fuel. ..

The first fuel injection valve 17 is arranged on the upper half 4a of the intake passage 4 and on the wall surface on the side of the second intake port.
The fuel is injected toward the first intake port 6. And
The fuel injected from the first fuel injection valve 17 is prevented from adhering to the swirl control valve 12, that is, the notch portion 15 of the swirl control valve 12.
The injection direction is set so as to be guided to the inside of the first intake port 6 via, and in particular, the injection direction is directed to the umbrella portion rear surface 19 of the first intake valve 8.

The second fuel injection valve 18 is disposed on the upper half portion 4a of the intake passage 4 and on the wall surface on the side of the first intake port, and injects fuel toward the second intake port 7.

The first fuel injection valve 17 and the second fuel injection valve 18 are symmetrically arranged as shown in the figure. When fuel is injected from both of them, the fuel from both is fed into the central axis L of the intake passage. Moreover, the particles directly collide with each other on the upstream side of the swirl control valve 12 to be atomized, and flow into both the first intake port 6 and the second intake port 7 without deviation.

The swirl control valve 12 is provided with a position sensor 20 for detecting the opening thereof, and the output of the position sensor 20 is input to the control unit 21. Then, the control unit 21 controls the injection timing of the first fuel injection valve 17 and the second fuel injection valve 18 based on the input from the position sensor 20.

Reference numeral 22 is an exhaust valve, 23 is a spark plug, and 24
Is a water jacket.

Next, the operation will be described based on such a configuration.

Regarding the opening and closing of the swirl control valve 12, the swirl control valve 12 is controlled so that it opens in an operating region below the stoichiometric air-fuel ratio and closes in an operating region in which the stoichiometric air-fuel ratio is exceeded, that is, lean burn is performed. Is notch 1 of swirl control valve 12
Although it depends on the aperture ratio of 5 and the like, it is determined based on a control map as shown in FIG. 3, for example. Then, as will be described later, in the lean combustion operating region in which the swirl control valve 12 is closed, fuel injection is performed only from the first fuel injection valve 17, and the swirl control valve 12 is opened in an operating region equal to or lower than the theoretical air-fuel ratio. In, the fuel is injected from both the first fuel injection valve 17 and the second fuel injection valve 18. In addition, SCV in the figure represents a swirl control valve, and Inj represents a fuel injection valve.

FIG. 4 is a diagram for explaining the fuel injection state when the swirl control valve is in the closed state, and FIG. 5 is a diagram for explaining the fuel injection state when the swirl control valve is in the open state. The open / closed state of 12 is determined based on the input from the position sensor 20, and the fuel injection timing of the first fuel injection valve 17 and the second fuel injection valve 18 is controlled.

That is, the swirl control valve 1
When it is determined that the second switch is in the closed state, as shown in FIG.
The fuel is injected only from the fuel injection valve 17, and the main portion of the fuel injected at this time does not adhere to the swirl control valve 12 and enters the first intake port 6 through the cutout portion 15 of the swirl control valve 12. Since the fuel is injected toward the back surface 19 of the intake valve 8, the fuel is not attached to the wall surface of the first intake port 6. Then, the flow velocity in the notch 15 where the air-fuel mixture introduced into the combustion chamber 5 is concentrated is high, and atomization of the fuel is promoted here. Therefore, when the swirl control valve is in the closed state, the main portion of the fuel injected from the first fuel injection valve is atomized without forming a wall flow, and the fuel-mixture mixture in which the atomization of the fuel is promoted is formed in the combustion chamber. A strong swirl flow is generated due to, resulting in stable lean combustion.

On the other hand, when it is determined that the swirl control valve 12 is open, fuel is injected from both the first fuel injection valve 17 and the second fuel injection valve 18, and the fuel injected from both collides with each other. Together with being atomized, they are evenly distributed and introduced into both the first intake port and the second intake port. In addition, since the main portion of the fuel thus injected passes above the swirl control valve 12 in the figure, it does not adhere to the swirl control valve 12. Therefore, problems such as delay in fuel transportation due to wall flow generation do not occur, and HC emissions can be reduced. In addition, hesitation such that the vehicle speed does not increase even when the accelerator is stepped on when starting or accelerating. It is possible to prevent improper acceleration, that is, stumble, that accompanies a decrease in output that occurs during acceleration.

[0028]

As described above, according to the present invention, the swirl control valve is provided on the combustion chamber side in order to obtain a strong swirl flow in the combustion chamber while preventing fuel from adhering to the swirl control valve. The mixture can be brought closer to each other, and when the swirl control valve is opened, the air-fuel mixture can be distributed and introduced into both the first intake port and the second intake port. In addition, regardless of whether the swirl control valve is open or closed, good atomization of fuel can be achieved. Can also be obtained.

Therefore, the optimum mixture is introduced into the combustion chamber of the engine in accordance with the opening / closing of the swirl control valve, and the exhaust gas can be cleaned and the drivability can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment according to the present invention.

FIG. 2 is a diagram showing an embodiment according to the present invention.

[Fig. 3] Control map of swirl control valve

FIG. 4 is a diagram for explaining a fuel injection state when the swirl control valve is closed.

FIG. 5 is a view for explaining a fuel injection situation when the swirl control valve is open.

FIG. 6 is a diagram showing a conventional intake device for an internal combustion engine.

[Explanation of symbols]

 4 intake passage 5 combustion chamber 6 first intake port 7 second intake port 11a upstream end 15 notch 12 swirl control valve 17 first fuel injection valve 18 second fuel injection valve

Claims (1)

[Claims] 1. A first intake port and a second intake port that branch from an intake passage and communicate with a combustion chamber of an engine, and an intake passage that is adjacent to a partition upstream end of the first intake port and the second intake port. A swirl control valve that is arranged to open and close the intake passage and has a notch in a portion facing the first intake port, and a first intake port that is directed toward the notch from the upstream side of the swirl control valve. A first fuel injection valve for injecting fuel inward and a second intake port arranged substantially upstream of the swirl control valve so as to collide with fuel injected from the first fuel injection valve. A second fuel injection valve for injecting fuel, the first fuel injection valve performs fuel injection when the swirl control valve is closed, and the first fuel injection when the swirl control valve is open. An intake system for an internal combustion engine, wherein fuel is injected from both the valve and the second fuel injection valve.