JPH0110415Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention includes a dome part that communicates with the combustion chamber inside the cylinder head, and a port part that is helically connected to the dome part through a throat part. The present invention relates to an intake system for an internal combustion engine.

[Prior art]

In general, a direct injection diesel engine is different from a gasoline engine in which fuel is mixed with air in a carburetor beforehand and then poured into the combustion chamber, or a pre-combustion chamber type diesel engine in which the above mixing is performed in a pre-combustion chamber. The fuel and air meet for the first time at , and mixing must take place within a very short period of time. Therefore, the quality of the mixture of fuel and air directly affects the combustion state, and the performance of the engine, such as output, torque, and
It affects the smoke etc.

One of the factors directly related to the quality of this mixture is
The other is the fuel injection action of the injection valve, and the other is the flow of the intake air, that is, the swirl of the intake air around the axis of the combustion chamber (hereinafter referred to as swirl).

In order to obtain the above-mentioned swirl, various intake devices have been proposed in the past, and FIGS. 1a and 1b show a helical port that is a typical device.
In the figure, inside the cylinder head 1, there is a dome part or spiral part 2 that communicates with a combustion chamber (not shown).
The dome part 2 is formed with a port part 4 that is connected in a helical shape through a throat part, that is, a protrusion part 3, and the intake manifold 5 is connected to the helical port part 4 and the throat part 3. When the fuel flows into the combustion chamber, it generates a swirl as shown by the chain arrow.

By the way, the strength of the swirl depends on the speed at which the intake air passes through the port section 4, and the strength of the swirl is usually adjusted optimally when the engine speed is in the medium speed range, in which case good combustion can be obtained. However, at high speeds, the swirl is too strong and the atomized fuel overlaps, and at low speeds the swirl is too weak, making it impossible to achieve optimal combustion at high speeds and low speeds.

In order to solve the above problem, for example,
As shown in Japanese Patent Publication No. 7365, Japanese Patent Publication No. 51-38730, and Japanese Patent Publication No. 51-7243, the port section 4
A swirl control piece made of a plate-like member having one end pivotally supported on the intake manifold 5 side of the port portion 4 and the other end being a free end extending near the dome portion 2 is disposed within the swirl control piece. It is known that the shape of the port portion 4 or the cross-sectional area of the intake air inlet is changed to achieve optimal combustion.
However, in all of these prior art techniques, swirl control is not sufficient, and even if swirl can be controlled, the control mechanism is complicated.

Further, for example, Japanese Utility Model Application Publication No. 53-116510 discloses a technique in which a portion of the wall surface of the opposing dome portion of the intake passage is movable. However, in such known technology, since a part of the wall surface is movable, there is a risk of air leaking from the joint between the fixed wall surface and the movable wall surface, and in addition, when modifying an existing internal combustion engine, it is practically impossible to modify the cylinder head. The whole thing has to be reprocessed.

Further, Japanese Utility Model Application Publication No. 54-180821 discloses a technique in which a variable swirl valve having a rotation center parallel to the valve stem is provided in an intake hole. However, in this known technique, the operating mechanism of the variable swirl valve is complicated, and it is virtually impossible to modify an existing internal combustion engine. Furthermore, Japanese Utility Model Application Publication No. 56-97526 discloses a technique in which a wall that is easily deformed and deformed is formed on a portion of the outflow side of the peripheral wall of the dome portion.
However, in this known technique, the deformation of the wall creates protrusions and pockets against the air flow.
This creates flow resistance and makes it virtually impossible to modify existing internal combustion engines.

Furthermore, Japanese Utility Model Application Publication No. 58-9928 discloses a method in which a swirl control piece is moved in a low speed range to narrow the cross-sectional area of the flow path, thereby preventing too much intake air flow from occurring in the central part of the combustion chamber. A technique has been disclosed to generate a strong swirl in the surrounding area.
However, since such a technique uses a ring-shaped control piece, there is a large loss in intake air flow, and it is also difficult to control the position of the control piece.

[Problem to be solved]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an intake system for an internal combustion engine that allows effective combustion to be achieved at all times with a simple control device, regardless of the operating state of the engine, and without flow loss.

[Means to solve the problem]

According to the present invention, in an intake system for an internal combustion engine, a dome portion communicating with a combustion chamber is formed inside a cylinder head, and a port portion helically connected to the dome portion via a throat portion. A swirl control piece movably configured to expand or contract the radius of the dome portion according to the engine operating condition is arranged along the peripheral wall of the dome on an extension side of the convex side wall of the port portion of the dome portion to have an outer shape similar to the inner wall. formed and provided;
An actuator for controlling the swirl control piece is attached to the intake manifold, and the swirl control piece is fixed to the tip of a rod extending from the actuator into the intake manifold and the port portion.

[Effect]

Therefore, during operation, the swirl control piece is brought close to the wall surface of the dome portion when the engine speed is low. As a result, the radius of the dome is expanded and the swirl becomes stronger. Conversely, at high engine speeds, the swirl control piece is reduced in diameter away from the dome wall, resulting in weakened swirl. In this way, effective combustion is always obtained, regardless of the operating conditions.

According to the present invention, since the swirl control piece is provided in a shape along the wall surface of the dome, the swirl can be suitably controlled and no resistance is generated to the flow. Therefore there is no flow loss. Furthermore, when improving an existing internal combustion engine to provide swirl control according to the present invention, the actuator can be installed in the intake manifold by simply inserting a swirl control piece into the port or by slightly modifying the dome. It only needs to be installed and modification is extremely easy. By simply operating the actuator provided on the intake manifold, the swirl control piece can adjust the interference with the dome wall surface and control the swirl, so the overall device is simple and highly effective.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 2 and 3. In these figures, all parts corresponding to those in FIG. 1 are designated by the same reference numerals.

In FIGS. 2a and 2b, on the extended side of the convex side wall 4b of the port portion of the dome portion 2, a swirl control piece 6 formed to have an external shape similar to that of the wall is disposed along the wall. On the other hand, an air cylinder 7 is attached to the outside of the intake manifold 5, and a rod 9 is fixed to a piston 8 housed inside the air cylinder 7 and biased toward the contraction side by a spring 11. protrudes into the inside of 5,
Further, the port portion 4 is guided by the rod guide 10.
The tip extends into the swirl control piece 6, and its tip is fixed to the swirl control piece 6. This air cylinder 7 is controlled by a swirl control piece 6 by a rod 9 via a piston 8 by supplying air controlled according to the engine speed.
can be moved forward and backward (left and right in the figure). Air supply may be controlled not only by engine speed but also by load.

Next, the effect will be explained.

When the engine speed is low, a large amount of air is supplied to the air cylinder 7, which presses the piston 8.
The swirl control piece 6 is controlled via the rod 9 as shown in Fig. 2a.
Move it to the position shown by the chain line. As a result, the radius of the dome portion 2 is expanded to R, and as a result, a strong swirl is obtained.

When the engine speed increases, the amount of air supplied decreases accordingly, and the piston 8 is urged by the spring 11 and moves toward the contraction side, thereby causing the swirl control piece 6 to separate from the wall of the dome portion 2. direction. At high speed, the radius of the dome portion 2 is reduced to R ^- at the position shown by the dashed line.
As a result, the swirl is weakened.

In this way, when the engine speed is low, the swirl control piece 6 is brought closer to the wall of the dome part 2, and the radius of the dome part 2 is expanded, resulting in a strong swirl, while at high speed, the swirl control piece 6
is separated from the wall of the dome part 2, the radius of the dome part 2 is reduced, and as a result, the swirl is weakened, which makes it easier to control the swirl and ensure effective combustion at all times regardless of operating conditions. be. Further, since the swirl control piece 6 and the air cylinder 7 can be attached to the intake manifold 5, the structure is simplified.

Figures 3a and 3b show another embodiment of the invention, in which the swirl control piece 6 is made of spring steel and its cylindrical end 6a is attached near the throat 3 of the concave side wall of the port. into the cylindrical recess 3',
In this example, the dome part 2 is formed so as to go around the dome part 2 and reach the port part convex side wall 4b, and the radius of the dome part 2 is expanded or contracted by moving the rod 9 back and forth to change the curvature of the entire swirl control piece 6. be. This embodiment also has the same effects as the embodiment shown in FIGS. 2a and 2b.

[Effect of idea]

As described above, according to the present invention, the swirl can be controlled by the reciprocating motion of the actuator, so control according to the operating state of the engine is easy, and there is little loss in flow.

Further, when improving an existing internal combustion engine, it is sufficient to insert the swirl control piece into the port portion, and the dome portion may be slightly modified if necessary, so that installation is easy. The device is also simple overall.

[Brief explanation of drawings]

FIG. 1 shows a conventional device, FIG. 1a is a side sectional view, FIG. 1b is a cross-sectional view, and FIGS.
is a cross-sectional view, and b is a perspective view of the swirl control piece. 2... Dome part, 3... Throat part, 4... Port part, 5... Intake manifold, 6... Swirl control piece, 7... Air cylinder.

Claims (1)

[Scope of utility model registration request] In an intake system for an internal combustion engine, in which a dome portion communicating with a combustion chamber and a port portion helically connected to the dome portion via a throat portion are formed inside the cylinder head, A swirl control piece movably configured to expand or contract the radius of the dome portion is provided along the peripheral wall of the dome on an extension side of the convex side wall of the port portion of the dome portion and has an outer shape similar to the inner wall; An intake system for an internal combustion engine, characterized in that an actuator for controlling the swirl control piece is attached to an intake manifold, and the swirl control piece is fixed to a tip of a rod extending from the actuator into the intake manifold and into the port section.