JPH07247850A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve controllability of an intake air flow by a swirl control valve. CONSTITUTION:A suction device for an internal combustion engine comprises a first swirl control valve 5 disposed in a position situated downstream from the fuel injection valve 3 of an intake air passage 2; a second swirl control valve 6 disposed in a position situated upper stream from the fuel injection valve 3 of the intake air passage 2; a first notch part opened to the first swirl control valve 5 in a state to offset radially of rotation thereof; and a second notch part opened to the second swirl control valve 6 in a state to offset axially of rotation of the first swirl control valve 5.

Description

Detailed Description of the Invention

[0001]

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

[0002]

As a method for obtaining stable combustion even if the air-fuel ratio of the air-fuel mixture is made lean, it is effective to generate an appropriate swirl or tumble intake swirl flow in the combustion chamber.

As a device for producing an intake swirl flow in a combustion chamber, for example, Japanese Utility Model Laid-Open No. 63-12635 and Japanese Utility Model Publication No. 1-
As seen in Japanese Patent No. 91038 and Japanese Utility Model Laid-Open No. 1-91039, there are some which are equipped with a swirl control valve which throttles intake air sucked into a combustion chamber according to operating conditions.

Conventionally, for example, as shown in FIG. 7 and FIG. 8, the swirl control valve 17 is rotatably supported in the intake passage 2 via a rotary shaft 18, and a notch portion 19 for allowing intake air to pass through when the swirl control valve 17 is closed is formed. ing.

When the swirl control valve 17 is closed under operating conditions such as low speed, most of the intake air is guided through the cutout portion 19 to increase the flow velocity of the intake air flowing into the combustion chamber 1 for combustion. An intake air swirl flow is generated in the chamber 1.

A fuel injection valve 3 is installed above the swirl control valve 17 in the intake passage 2. A concave portion 4 facing the fuel injection valve 3 is formed on the inner wall surface 21 of the intake passage 2.
The intake passage 2 branches into two intake ports that open into the combustion chamber 1 of one cylinder, and the fuel injection direction of the fuel injection valve 3 is directed to each intake port.

[0007]

As shown in FIG. 9, such a conventional intake system burns as the swirl control valve 17 moves away from a reference position where the swirl control valve 17 is attached to the upstream side of the intake passage 2. The tumble ratio of the intake swirl flow generated in the chamber 1 becomes small. Therefore, there is a demand for bringing the swirl control valve 17 closer to the combustion chamber 1 in order to increase the power of the tumble generated in the combustion chamber 1.

However, when the swirl control valve 17 is brought close to the combustion chamber 1, the fuel spray A injected from the fuel injection valve 3 collides with the swirl control valve 17, so that it takes time for the fuel to reach the combustion chamber 1. As a result, there arises a problem that the control response of the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber 1 is deteriorated at the transition of the change in the fuel injection amount, which causes deterioration of exhaust emission.

In view of the above problems, the present invention aims to improve the controllability of the intake flow by the swirl control valve in the intake system of an internal combustion engine.

[0010]

The invention according to claim 1 is
A fuel injection valve for injecting fuel into the intake passage, a first swirl control valve rotatably supported downstream of the fuel injection valve in the intake passage, and located upstream of the fuel injection valve in the intake passage. Second swirl control valve, which is rotatably supported by the first swirl control valve, and drive means for opening and closing the first and second swirl control valves in synchronization with each other. The first notch portion that is offset and opened, and the second notch portion that is offset and opened in the rotation axis direction of the first swirl control valve are provided in the second swirl control valve.

According to a second aspect of the present invention, in the first aspect of the invention, the first notch portion is arranged above the rotation axis of the first swirl control valve.

[0012]

In the invention according to claim 1, when the first and second swirl control valves are in the fully closed position, the intake air is guided through the second and first notches in this order, and The intake flow velocity is increased on the downstream side of the portion where the second and first cutouts are open, and an intake swirl flow having swirl and tumble velocity components is generated in the combustion chamber. As a result, mixing of fuel spray and air is promoted by the intake swirling flow, and combustibility is enhanced.

By restricting the flow of intake air by the second and first notches arranged in series in the intake passage, a large opening area of the first notch located downstream of the fuel injection valve is secured. Therefore, it is possible to easily prevent the fuel spray from colliding with the first swirl control valve. As a result, the fuel injected from the fuel injection valve can be promptly guided to the combustion chamber and the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber can be controlled with good responsiveness, and exhaust emission can be improved.

In the second aspect of the invention, when the first and second swirl control valves are in the fully closed position, the second notch opening in the side of the intake passage allows the intake flow to flow into the side of the intake passage. , The swirl is generated in the combustion chamber, while the first notch opening in the upper portion of the intake passage collects the intake air flow in the upper portion of the intake passage to generate tumble in the combustion chamber.

By arranging the first swirl control valve that causes tumble downstream of the second swirl control valve that causes swirl, it is possible to increase the power of the tumble from the swirl in the combustion chamber. As a result, the lean limit air-fuel ratio is increased, and stable combustibility can be obtained even when the lean air-fuel mixture is supplied.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings.

In FIG. 1, 2 is an intake passage of the engine, and 1 is a combustion chamber. The intake passage 2 branches into two intake ports that open to the combustion chamber 1 of one cylinder downstream of a first swirl control valve 5 described later, and the opening of each intake hoat with respect to the combustion chamber 1 rotates the engine. Intake valves that open and close in synchronization with are respectively provided.

A fuel injection valve 3 is installed upstream of a branch portion of each intake port of the intake passage 2. A concave portion 4 facing the fuel injection valve 3 is formed on the inner wall surface 21 of the intake passage 2.
The fuel injection direction of the fuel injection valve 3 is directed toward the back of the intake valve.

In the intake passage 2, first and second swirl control valves 5 and 6 are arranged in series. The first swirl control valve 5 is arranged downstream of the injection port 13 of the fuel injection valve 3 in the intake passage 2. The second swirl control valve 6 is provided in the injection port 1 of the fuel injection valve 3 in the intake passage 2.
It is arranged on the upstream side of 3.

As shown in FIG. 4, flat plate-shaped first and second swirl control valves 5 and 6 are rotatably supported via rotary shafts 7 and 8. Each rotating shaft 7, 8
They are arranged in the horizontal direction orthogonal to the cylinder axis, in the direction orthogonal to the intake passage center line, and supported in parallel with each other. Arms 27 and 28 are coupled to one ends of the rotary shafts 7 and 8, respectively, and the arms 27 and 28 are rotatably coupled to each other via a link 11, via which they rotate in synchronization with each other. It is designed to move.

The diaphragm type actuator 12 is connected to one arm 27. The control device operates the actuator 12 according to the contents of the map preset according to the operating state of the engine, and controls the opening degrees of the first and second swirl control valves 5 and 6.

The first and second swirl control valves 5 and 6 are held in their fully closed positions at rotational positions substantially orthogonal to the passage center line of the intake passage 2 as shown by the solid line in FIG. In this position, the intake passage 2 is held at a rotational position substantially parallel to the passage center line as shown by the broken line in FIG.

As shown in FIG. 2, the first swirl control valve 5 is provided with a first notch 9 which is offset and opened in the radial direction of rotation of the first swirl control valve 5.

The first notch 9 is formed by notching a portion above the rotary shaft 7 at the closed position of the first swirl control valve 5. That is, in the fully closed position of the first swirl control valve 5, the first cutout portion 9 defines a half-moon shaped space above the intake passage 2, and the fuel spray injected from the fuel injection valve 3 is first injected. While passing through the first cutout portion 9 without colliding with the swirl control valve 5, the intake air flow passing through the first cutout portion 9 is collected in the upper part of the intake passage 2 to be parallel to the crankshaft in the combustion chamber 1. It is configured to generate a tumble that vertically swivels around a different axis.

As shown in FIG. 3, the second swirl control valve 6 is formed with a second notch 10 which is offset and opened in the direction of the rotation axis of the first swirl control valve 5.

The second cutout portion 10 is open to a side portion of the intake passage vertical center line O which is orthogonal to the rotation axis 8.
That is, at the fully closed position of the second swirl control valve 6, the second cutout portion 10 defines a half-moon shaped space on the side portion of the intake passage 2, and the intake flow passing through the second cutout portion 10 is sucked. Collected on the side of the passage 2, it is configured to generate a swirl in the combustion chamber 1 that swirls laterally about the cylinder axis.

With the above construction, the operation will be described below.

When the first and second swirl control valves 5 and 6 are opened under operating conditions such as high speed, intake air is evenly guided to the two intake ports. When the first and second swirl control valves 5 and 6 are closed under operating conditions such as low speed, most of the intake air is in the second and first cutouts 9 and 10.
Is introduced into one of the intake ports through the intake passage 2 and flows into the combustion chamber 1 from the intake passage 2 to increase the intake flow velocity, thereby producing an intake swirl flow having velocity components of swirl and tumble in the combustion chamber 1.
The intake swirl flow promotes the mixing of fuel spray and air, and good combustion properties are obtained.

When the first and second swirl control valves 5 and 6 are in the fully closed position, the second cutout portion 10 defining the half-moon shaped space on the side of the intake passage 2 allows the intake flow to flow. 2 to collect swirl in the combustion chamber 1 while collecting the intake flow to the upper part of the intake passage 2 by the first notch 9 which defines a half-moon shaped space in the upper part of the intake passage 2. Then, tumble is generated in the combustion chamber 1.

FIG. 5 shows the results of measuring the lean limit air-fuel ratio at which stable combustibility is obtained by changing the tumble ratio and swirl ratio. From this experimental result, it is understood that the lean limit air-fuel ratio can be increased by increasing the tumble ratio rather than the swirl ratio.

According to the present invention, by arranging the first swirl control valve 5 that causes tumble downstream of the second swirl control valve 6 that causes swirl, the power of the tumble is increased in the combustion chamber 1 rather than the swirl. Is possible. As a result, the lean limit air-fuel ratio is increased, and stable combustibility can be obtained even when the lean air-fuel mixture is supplied.

The first notch portion 9 is formed by notching a portion above the rotary shaft 7 at the fully closed position of the first swirl control valve 5, and forms a portion of the intake passage 2 near the injection port 13 of the fuel injection valve 3. By defining a half-moon shaped space in the upper part, the fuel spray injected from the fuel injection valve 3 does not collide with the first swirl control valve 5,
The first notch 9 is passed through. As a result, the fuel injection valve 3
It is possible to promptly guide the fuel injected from the combustion chamber 1 to the combustion chamber 1 and control the air-fuel ratio of the air-fuel mixture supplied to the combustion chamber 1 with good responsiveness, and improve the exhaust emission.

Next, in the first swirl control valve 5 according to another embodiment shown in FIG. 6, the first notch portion 9 is formed in a portion above the rotary shaft 7 in the closed position, and the first notch portion is provided. It has a guide portion 16 that closes a side portion of the portion 9. In addition, the same reference numerals are used for the portions corresponding to those in FIGS.

As described above, the first notch 9 is formed in the first swirl control valve 5 so as to be offset in the radial direction and the rotation axis direction of the first swirl control valve 5 while opening the first swirl control valve 5, as shown in FIG. The second swirl control valve 6 is formed with a second notch 10 which is offset and opened in the same direction as the first notch 9 in the rotation axis direction of the first swirl control valve 5.

Even when the first swirl control valve 5 is in the fully closed position, the guide portion 16 is formed so as not to collide with the fuel spray A injected from the fuel injection valve 3.

In this case, the intake flow collected in the lateral portion of the intake passage 2 by passing through the second cutout portion 10 of the second swirl control valve 6 is narrowed by the guide portion 16 of the first swirl control valve 5. The swirl generated in the combustion chamber 1 can be increased in power by being collected in the lateral portion of the intake passage 2 even when passing through the first cutout portion 9.

[0037]

As described above, the intake device for the internal combustion engine according to the first aspect of the present invention is capable of rotating, being positioned at a fuel injection valve for injecting fuel into the intake passage and at a position downstream of the fuel injection valve in the intake passage. A first swirl control valve supported by
A second swirl control valve that is rotatably supported at a position upstream of the fuel injection valve in the intake passage;
A drive means for opening and closing the second swirl control valve in synchronization, a first notch opening in the first swirl control valve that is offset in the radial direction of rotation of the first swirl control valve, and a second swirl control valve. One swirl control valve is provided with a second notch portion that is opened by being offset in the rotation axis direction,
The combustibility can be improved by causing an intake swirl flow having velocity components of swirl and tumble in the combustion chamber without causing the fuel spray to collide with the swirl control valve.

According to a second aspect of the present invention, in the first aspect of the invention, since the first notch portion is arranged above the rotation axis of the first swirl control valve, the tumble force is increased from the swirl in the combustion chamber. It becomes possible to increase the lean limit air-fuel ratio and to obtain stable combustibility even when a lean air-fuel mixture is supplied.

[Brief description of drawings]

FIG. 1 is a sectional view of an intake passage and the like showing an embodiment of the present invention.

FIG. 2 is a front view of the first swirl control valve.

FIG. 3 is a front view of the second swirl control valve.

FIG. 4 is a perspective view of a rotary shaft and its drive system.

FIG. 5 is a characteristic diagram showing a relationship between a swirl ratio, a tumble ratio, and a lean limit air-fuel ratio.

FIG. 6 is a front view of a first swirl control valve showing another embodiment.

FIG. 7 is a sectional view of an intake passage and the like showing a conventional example.

FIG. 8 is a front view of the first swirl control valve.

FIG. 9 is a characteristic diagram showing the relationship between the position of the swirl control valve and the tumble ratio.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustion chamber 2 Intake passage 3 Fuel injection valve 5 First swirl control valve 6 Second swirl control valve 7 Rotating shaft 8 Rotating shaft 9 First cutout portion 10 Second cutout portion 12 Actuator

Claims (2)

[Claims] 1. A fuel injection valve for injecting fuel into an intake passage, a first swirl control valve rotatably supported downstream of a fuel injection valve in the intake passage, and a fuel injection valve for the intake passage. A second swirl control valve located on the upstream side and rotatably supported, a drive means for opening and closing the first and second swirl control valves in synchronization, and a first swirl control valve for the first swirl control valve. The first swirl control valve has a first notch that is offset and opened in the radial direction, and the second swirl control valve has a second notch that is offset and opened in the rotational axis direction of the first swirl control valve. An intake device for an internal combustion engine. 2. The intake system for an internal combustion engine according to claim 1, wherein the first notch portion is arranged above the rotation axis of the first swirl control valve.