JPH07189711A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To heighten the controllability of intake air flow by a swirl control valve in an intake device for an internal combustion engine. CONSTITUTION:An intake device for an internal combustion engine is provided with a swirl control valve 1 rotatably supported at an intake passage 2 through a rotary shaft, and a cutout part 5 for passing intake air to the swirl control valve 1 is formed being offset from the center of an intake passage 2. In such an intake device, the swirl control valve 1 has a spirally curved cutout side valve body part 6 and an anti-cutout side valve body part 7 formed as the inclined faces to collect intake air toward the cutout part 5 in relation to the direction of the rotation axis.

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]

2. Description of the Related Art As a method of obtaining stable combustion even at low speed, it is effective to generate an appropriate swirl (swirl flow) in the combustion chamber.

As a device for producing a swirl, for example, as disclosed in Japanese Utility Model Laid-Open No. 2-92030, there is a device provided with a swirl control valve that throttles intake air sucked into a combustion chamber according to operating conditions.

As a conventional swirl control valve, there is a swirl control valve that is rotatably supported in an intake passage via a rotary shaft and has a notch formed at one end thereof offset from the center line of the intake passage. When the swirl control valve is closed, the intake air sucked into the combustion chamber is throttled to increase the flow velocity of the intake air sucked into the combustion chamber from the intake port to generate swirl in the combustion chamber.

[0005]

However, since such a conventional swirl control valve has a flat plate shape, the flow of intake air cannot be smoothly controlled during the process of opening the swirl control valve. However, there is a problem that the swirl power cannot be obtained sufficiently.

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

[0007]

The invention according to claim 1 is
A swirl control valve rotatably supported in the intake passage via a rotary shaft is provided, and a notch portion for passing intake air when the swirl control valve is closed is formed by being offset from the center of the intake passage. In the intake device, the swirl control valve is formed with an inclined surface that collects intake air toward the cutout portion in the rotational axis direction.

According to a second aspect of the present invention, in the intake system for an internal combustion engine according to the first aspect of the invention, the swirl control valve is formed in a thin plate shape, and the swirl control valve is curved in a spiral shape.

According to a third aspect of the present invention, there is provided an intake system for an internal combustion engine according to the first or second aspect of the invention, wherein the projected aperture ratio of the intake passage by the swirl control valve is the swirl control valve in a process of rotating. It is configured so that it becomes smaller at the part away from the notch.

[0010]

According to the present invention, the intake air is smoothly collected toward the cutout portion by the inclined surface of the swirl control valve, and the intake airflow velocity which is taken into the combustion chamber through the intake port is set to the central portion of the combustion chamber. By increasing the outer peripheral portion, the power of the swirl generated in the combustion chamber can be increased. As a result, the mixing of fuel spray and air is promoted, and good combustibility is obtained.

According to the second aspect of the present invention, the intake air is smoothly collected toward the cutout portion by the inclined portion of the swirl control valve which is spirally curved, and the intake air flow rate is taken into the combustion chamber through the intake port. The power of the swirl generated in the combustion chamber can be increased by increasing the power in the outer peripheral portion of the combustion chamber rather than in the central portion.

In the third aspect of the present invention, the projected opening ratio of the intake passage by the swirl control valve becomes smaller at a portion apart from the cutout portion in the process of rotating the swirl control valve, so that the intake air is cut out. The swirl force generated in the combustion chamber can be increased by increasing the flow velocity of the intake air that is smoothly collected in the combustion chamber and sucked into the combustion chamber through the intake port in the outer peripheral portion than in the central portion of the combustion chamber. .

[0013]

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

In FIG. 1, 1 is a swirl control valve and 2 is an intake passage of the engine. The intake passage 2 has an oval cross-sectional shape, and a space 3 located above the swirl control valve 1 and facing a fuel injection valve (not shown) is concavely formed. The fuel injection valve has its fuel injection direction directed toward the back of the intake valve.

The swirl control valve 1 is rotatably supported via a rotary shaft (not shown). A line segment X in the drawing is a rotation center line of the rotation shaft of the swirl control valve 1.

The thin plate-shaped swirl control valve 1 is joined to the inner wall of the intake passage 2 at its fully closed position, or the outer peripheral edge portion 4 facing each other with a small gap, and a switch for passing intake air away from the inner wall of the intake passage 2. And a notch portion 5.

When the swirl control valve 1 is in the fully closed position, the notch 5 is located above the rotation center line X and on the side of the intake passage 2,
The intake passage 2 is offset and opened with respect to the passage center line O.

As shown in FIG. 2, the thin plate-shaped swirl control valve 1 has a spirally curved notch-side valve body portion 6 as an inclined surface for collecting intake air toward the notch portion 5 in the direction of its rotation axis. And the anti-notch side valve body portion 7.

When the swirl control valve 1 is in the fully closed position, the cutout side valve body portion 6 extending downward from the cutout portion 5 is inclined toward the upstream side of the intake passage 2 from its upper portion to its lower portion. While being twisted, the anti-notch side valve body portion 7 having a smaller opening area of the notch portion 5 is twisted so as to incline toward the downstream side of the intake passage 2 from its lower portion to its upper portion.

As shown in FIG. 3, in the swirl control valve 1, each cross section parallel to the rotation center line X extends linearly, and each cross section when the swirl control valve 1 is viewed from above is shown in FIG. It inclines largely with respect to the rotation center line X as it separates from.

As shown in FIG. 4, the rotation direction of the swirl control valve 1 is set so that the notch 5 falls to the downstream side of the intake passage 2, and the projection opening of the intake passage 2 by the swirl control valve 1 is made. The ratio is configured so that the anti-notch side valve body portion 7 becomes smaller than the notch side valve body portion 6 in the process of rotating the swirl control valve 1.

FIG. 5 shows that when the swirl control valve 1 is rotated from the fully closed position where the rotation angle is 0 ° to the fully opened position where it is 60 °, the projected aperture ratio of the intake passage 2 changes according to the rotation angle. The characteristic shows that the projected aperture ratio changes approximately proportionally between 25 and 80%. The shaded area in the figure indicates the projected area occupied by the rotation axis.

Two holes 8 are formed on the center line X of rotation of the swirl control valve 1, and the swirl control valve 1 is fastened to the rotary shaft via screws (not shown) penetrating the respective holes 8.

The rotary shaft of the swirl control valve 1 is rotationally driven in accordance with the operating state of the engine by a diaphragm type actuator, a step motor or the like not shown. The control device controls the opening degree of the swirl control valve 1 in accordance with the contents of a map preset according to the operating state of the engine.

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

With the swirl control valve 1 held in the fully closed position, most of the intake air is guided through the cutout 5. At this time, the intake air is guided toward the cutout portion 5 by the cutout side valve body portion 6 which is inclined also in the rotation axis direction.

Even in the process of rotating the swirl control valve 1 from the fully closed position to the fully open position, the intake air is smoothly collected toward the notch 5 by the inclined portion of the swirl control valve 1 which is spirally curved.

Further, the projected area occupied by the swirl control valve 1 in the intake passage 2 is larger in the anti-notch side valve body portion 7 than in the notch side valve body portion 6, and the ratio is the opening degree of the swirl control valve 1. The intake air is effectively collected toward the cutout portion 5 because the intake air is effectively changed toward the cutout portion 5 because the intake air is gradually changed with the increase.

In this way, the swirl control valve 1 allows the flow of intake air passing therethrough to smoothly cut out the notch portion 5.
By increasing the flow velocity of the intake air introduced into the combustion chamber through the intake port toward the outer peripheral portion of the combustion chamber, the swirl force generated in the combustion chamber can be increased. As a result, the mixing of fuel spray and air is promoted, and good combustibility is obtained.

Next, another embodiment shown in FIG. 6 has a portion in which the cross section orthogonal to the rotation center line X of the swirl control valve 11 is curved in an S shape. The curvature of the S-shaped cross section increases as the distance from the opening of the cutout portion 15 increases in the rotation axis direction.

In this case, the swirl control valve 1
1 rotates in the direction indicated by the arrow in the figure, but the intake air is cut in the cutout portion 15 by a portion twisted so as to incline from the upstream side toward the cutout portion 15 of the swirl control valve 11 as shown by the arrow in the figure. Be guided to. As a result, the swirl control valve 11 smoothly guides the flow of intake air passing therethrough toward the notch portion 5, and the intake air flow velocity taken into the combustion chamber through the intake port is changed from the central portion of the combustion chamber to the outer peripheral portion. The power of the swirl generated in the combustion chamber can be increased. As a result, the mixing of fuel spray and air is promoted, and good combustibility is obtained.

Next, in another embodiment shown in FIG. 7, the swirl control valve 21 is formed in a thick plate shape and its cross-sectional shape is changed in the direction of the rotation axis.

As shown in FIGS. 8 and 9, when the swirl control valve 21 is in the fully closed position, an inclined surface 26 inclined toward the notch 25 is formed on the side facing the upstream side of the intake passage. It is formed.

The upper and lower end portions 23, 24 of the swirl control valve 21 are formed by being curved in an arc shape centered on the rotation center line X thereof.

The swirl control valve 21 is formed by cutting out using an aluminum material or the like.

With the above construction, the operation will be described.

During the process in which the swirl control valve 21 rotates from the fully closed position to the fully open position, the intake air is notched into the cutout portion 2.
It is guided toward the cutout portion 25 by the inclined surface 26 inclined toward 5.

When the swirl control valve 21 opens in the direction shown by the arrow in FIG. 9 from the fully closed position, the arc-shaped upper end portion 23 maintains a constant gap with the inner wall of the intake passage within a predetermined angle range. As a result, the flow of the intake air that passes through this gap is suppressed, and the intake air is collected toward the cutout portion 25.

In this way, the swirl control valve 21 smoothly guides the flow of intake air passing therethrough toward the notch portion 25, and the intake air flow velocity sucked into the combustion chamber through the intake port is controlled by the combustion chamber. The swirl force generated in the combustion chamber can be increased by increasing the height of the swirl from the central part toward the outer peripheral part.
As a result, the mixing of fuel spray and air is promoted, and good combustibility is obtained.

[0040]

As described above, the intake system for the internal combustion engine according to claim 1 is provided with the swirl control valve rotatably supported in the intake passage via the rotary shaft, and the swirl control valve is closed when the swirl control valve is closed. In an intake device for an internal combustion engine, which is formed by offsetting a cutout portion for passing intake air with respect to the center of an intake passage, the swirl control valve is formed with an inclined surface for collecting intake air toward the cutout portion in the rotational axis direction thereof. Therefore, the intake air is smoothly collected toward the notch by the inclined surface of the swirl control valve, and the intake flow velocity that is taken into the combustion chamber through the intake port is increased from the central portion of the combustion chamber to the outer peripheral portion. , The swirl power generated in the combustion chamber can be increased.
As a result, mixing of fuel spray and air is promoted, and stable combustion can be obtained even at low speed.

In the intake system for an internal combustion engine according to a second aspect of the present invention, in the first aspect of the invention, the swirl control valve is formed in a thin plate shape, and the swirl control valve is curved in a spiral shape. Combustion is increased by increasing the flow velocity of the intake air that is smoothly collected toward the notch by the inclined part of the curved swirl control valve and is drawn into the combustion chamber through the intake port from the central part of the combustion chamber to the outer peripheral part. A strong swirl is generated in the chamber, and good flammability is obtained.

According to a third aspect of the present invention, there is provided the intake system for an internal combustion engine according to the first or second aspect, wherein the projected aperture ratio of the intake passage by the swirl control valve is the swirl control valve in the course of rotation. Since it is configured to become smaller at the part away from the notch,
The intake air is smoothly collected toward the notch, and the flow velocity of the intake air that is drawn into the combustion chamber through the intake port is increased from the central portion of the combustion chamber to the outer peripheral portion, which creates a strong swirl in the combustion chamber. Good flammability is obtained.

[Brief description of drawings]

FIG. 1 is a front view of a swirl control valve and the like showing an embodiment of the present invention.

FIG. 2 is a side view of a swirl control valve and the like.

FIG. 3 is a sectional view of the swirl control valve.

FIG. 4 is an explanatory view showing an operating state of the swirl control valve.

FIG. 5 is a characteristic diagram showing a projected aperture ratio of the intake passage according to the opening degree of the swirl control valve.

FIG. 6 is a front view and a cross-sectional view of a swirl control valve showing another embodiment.

FIG. 7 is a contour diagram of a swirl control valve showing yet another embodiment.

FIG. 8 is a side view of a swirl control valve and the like.

FIG. 9 is a sectional view of the swirl control valve.

[Explanation of symbols]

 1 Swirl control valve 2 Intake passage 5 Notch portion 6 Notch side valve body portion 7 Anti-notch side valve body portion 11 Swirl control valve 15 Notch portion 21 Swirl control valve 23 Upper end portion 24 Lower end portion 25 Notch portion 26 Sloping surface

Claims (3)

[Claims] 1. A swirl control valve rotatably supported in an intake passage via a rotary shaft, wherein a notch for passing intake air when the swirl control valve is closed is offset from the center of the intake passage. In the intake device for an internal combustion engine to be formed, an intake device for an internal combustion engine, wherein the swirl control valve is formed with an inclined surface for collecting intake air toward the cutout portion in a rotational axis direction thereof. 2. The intake system for an internal combustion engine according to claim 1, wherein the swirl control valve is formed in a thin plate shape, and the swirl control valve is curved in a spiral shape. 3. The projection opening ratio of the intake passage by the swirl control valve is configured to become smaller at a portion apart from the cutout portion in a process of rotating the swirl control valve. Item 3. An intake device for an internal combustion engine according to item 1 or 2.