JPH0130607Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an intake manifold equipped with a distribution chamber for distributing intake air to each combustion chamber of a multi-cylinder engine. This invention relates to an intake manifold for a multi-cylinder engine, which is cylindrical and has a single-barrel throttle body attached to one end.

(Prior Art) In multi-cylinder engines such as automobile engines, an intake manifold with a distribution chamber is used to ensure that intake air supplied through one throttle body is evenly distributed to each combustion chamber. often. Particularly in the case of fuel-injected engines, the intake manifold is often substantially L-shaped in profile. Such an L-shaped intake manifold includes a cylindrical distribution chamber that is arranged approximately horizontally on the side of the engine body, and a plurality of gently curved and approximately horizontally extending cylinders that extend downward from the bottom surface of the distribution chamber. It is formed by the intake pipe line. Each intake pipe is arranged in parallel,
The openings are arranged in sequence in the longitudinal direction of the distribution chamber.

Typically, such a cylindrical distribution chamber has an open end face to form an intake inlet, and intake air is introduced into the distribution chamber from a throttle body attached to the end face through the intake inlet. It's summery.

By the way, in the case of automobile engines, the throttle body has a simple structure and can provide good response in all operating ranges.
A single barrel type is often used. Such a single barrel type throttle body has a circular opening. Therefore, when using a single barrel throttle body and an intake manifold having a cylindrical distribution chamber as described above, the intake inlet of the distribution chamber should be , it must be circular to match the opening in the throttle body.

Conventionally, in such cases the entire distribution chamber has been formed of constant circular cross-section.

(Problems to be Solved by the Invention) However, in an intake manifold having a cylindrical distribution chamber, each intake pipe line extends along the longitudinal direction of the distribution chamber as described above.
They are opened in order from the side closer to the intake inlet. Therefore, the first
The flow velocity of intake air is high near the opening of the intake pipe,
Moreover, since the conduit forms a large angle with respect to the flow direction of the intake air in the distribution chamber, there is a problem in that the intake air is difficult to be distributed to the first intake conduit.

The distribution chamber can be made to have a large diameter to reduce the flow velocity of intake air inside the chamber, but in the case of a distribution chamber with a circular cross section, if the diameter is increased, the width and height will be increased. When used in an automobile engine for which installation space is limited, securing the space becomes a problem. Furthermore, if the flow velocity of the intake air in the distribution chamber is lowered overall, it becomes difficult for the intake air to be distributed to the intake pipe path on the side far from the intake air introduction port.

The present invention was developed in view of these problems, and its purpose is to provide an intake manifold that is compact and has high distribution efficiency even though it has a circular intake inlet. be.

(Means for Solving the Problem) In order to achieve this objective, the present invention makes the cross-sectional shape of the distribution chamber approximately square at the portion where the first intake pipe closest to the intake inlet of the distribution chamber opens. From the intake inlet to the vicinity of the opening position of the first intake pipe, the cross-sectional shape of the distribution chamber smoothly changes from circular to approximately square, and the cross-sectional area thereof increases. Then, beyond the opening position of the first intake pipe,
On the contrary, the cross-sectional area is gradually reduced.

(Function) In this way, by making the cross-sectional shape of the distribution chamber at the opening position of the first intake pipe substantially square, the cross-sectional area of the distribution chamber can be expanded without changing the width and height of the distribution chamber. . By making the cross-sectional area of the distribution chamber gradually expand from the intake inlet to the opening position of the first intake pipe, the intake air flowing into the distribution chamber is distributed near the opening of the first intake pipe. Since the flow velocity decreases the most, intake air is reliably distributed to the first intake pipe. Furthermore, as the cross-sectional area of the distribution chamber gradually decreases beyond the opening position of the first intake pipe, the flow velocity of intake air is gradually increased, and the opening is opened at the position farthest from the intake air inlet. Intake air is also forced into the intake pipe.

(Example) Hereinafter, an example of the present invention will be described using the drawings.

The figure shows an embodiment of the intake manifold according to the present invention, and Figures 1, 2, and 3 are a cutaway plan view, a rear view, and a side view of the intake manifold as seen from the intake inlet side, respectively. FIG. 4 is a vertical sectional view of the main part of the intake manifold. Also,
FIG. 5 is a schematic side view of the engine with its intake manifold.

As is clear from FIG. 5, the cylinder head 2 of the engine body 1 is provided with an intake port 4 that communicates with the combustion chamber 3 and opens on one side of the cylinder head 2. An intake manifold 5 is attached to the side surface of the cylinder head 2 where the intake port 4 opens. The intake manifold 5 includes a distribution chamber 6 arranged laterally at a distance from the engine body 1 and an intake conduit 7 connecting the distribution chamber 6 to the intake port 4 .

The engine main body 1 is an in-line four-cylinder engine, and the distribution chamber 6 of the intake manifold 5 has a cylindrical shape that is substantially parallel to the engine main body 1 and extends substantially horizontally. Further, as shown in FIG. 1, the intake pipe 7 has four pipes corresponding to the number of cylinders, namely, a first intake pipe 7 ₁ , a second intake pipe 7 ₂ , and a third intake pipe 7 2 . It consists of a pipe 7 ₃ and a fourth intake pipe 7 ₄ . Each of the conduits 7 ₁ to 7 ₄ extends downwardly from the distribution chamber 6 in parallel with one another, and furthermore extends in a gently curved and substantially horizontal manner. A common mounting flange 8 is provided at the end thereof, and is fixed to the side surface of the cylinder head 2 and connected to the four intake ports 4 by this mounting flange 8. .

Thus, as shown in FIG. 5, the entire intake manifold 5 is approximately L when viewed from the side.
It is said to be shaped like a letter. Further, an air cleaner 9 is attached to the back surface thereof. Furthermore, a fuel injection nozzle 10 capable of injecting fuel into each intake port 4 of the cylinder head 2 is attached to the mounting flange 8.

As is clear from FIGS. 1 and 2, the cylindrical distribution chamber 6 is open at one end, thereby forming an intake inlet 11. As shown in FIGS. A mounting flange 13 for mounting the throttle body 12 is provided on the end face thereof. Throttle body 12 is a single barrel type,
The intake air metered by a single throttle valve 12a,
It is adapted to be supplied from a single circular opening 12b. Therefore, as shown in FIG. 3, the intake inlet 11 of the distribution chamber 6 is also circular and is adapted to match the opening 12b of the throttle body 12.

Further, on the lower surface of the distribution chamber 6, openings 14 ₁ to 14 ₄ of the respective intake pipes 7 ₁ to 7 ₄ are provided on the lower surface of the distribution chamber 6.
are arranged in parallel in the longitudinal direction. The width of the distribution chamber 6 is, as shown in _FIG .
It gradually expands up to the position of the opening 14 ₁ , and gradually contracts from the first opening 14 ₁ to the end surface on the opposite side from the air intake inlet 11 . On the other hand, the height of the distribution chamber 6 varies from the intake inlet 11 to the first opening 14 ₁ as shown in FIG.
It gradually increases up to the position , and remains approximately constant thereafter. Furthermore, as shown in FIG. 4, the cross-sectional shape of the distribution chamber ₆ is circular at the line AA in FIG. It is considered to be a quadrilateral. During this period, the shape changes smoothly. Therefore, from the intake inlet 11 to the first opening ₁₄₁ position, the cross-sectional shape of the distribution chamber 6 smoothly changes from a circular shape to a substantially square shape, and its cross-sectional area increases. Also, the first
On the side opposite the air intake inlet 11 from the opening ₁₄₁ position, the cross-sectional shape of the distribution chamber 6 is approximately square, so that its cross-sectional area gradually decreases.

In an engine equipped with such an intake manifold 5, during operation, intake air that is taken in through the air cleaner 9 and purified is guided to the throttle body 12 via the air duct, and then
After being metered by a, it is introduced into the distribution chamber 6 through the intake inlet 11. The air is then distributed to the intake pipes 7 ₁ to 7 ₄ in the distribution chamber 6 and led to the corresponding combustion chambers 3 via the intake ports 4 of the cylinder head 2 . Meanwhile, fuel is injected from the fuel injection nozzle 10 toward each intake port 4, and the fuel is supplied to the combustion chamber 3 together with intake air.

During this period, while the intake air introduced into the distribution chamber 6 flows from the intake inlet 11 to the position of the first opening ₁₄₁ , the cross-sectional area of the distribution chamber 6 gradually expands, so that the flow rate increases. be gradually lowered. The flow velocity is the lowest near the first opening ₁₄₁ position. Therefore,
The first intake conduit 7 ₁ connected to its first opening 14 ₁ ensures that the intake air flows through the distribution chamber 6, even though it forms a large angle to the flow direction of the intake air in the distribution chamber 6. will be distributed.

In addition, the intake air flowing in the distribution chamber 6 in the longitudinal direction and passing through the first opening 14 ₁ is caused by the fact that the cross-sectional area of the distribution chamber 6 gradually decreases as it moves away from the intake inlet 11 . The flow rate increases gradually. Therefore, an appropriate flow velocity can be obtained at the second opening 14 ₂ position and the third opening 14 ₃ position, and the opening is also provided in the fourth intake pipe 7 ₄ which is farthest from the intake inlet 11. 14 From ₄ onwards, the intake air will be pushed in.

In this way, the intake air introduced into the distribution chamber 6 is distributed approximately equally to each of the intake conduits 7 ₁ to 7 ₄ .

By making the cross-sectional shape of the distribution chamber 6 at the first opening ₁₄₁ substantially square, the maximum cross-sectional area can be obtained within a certain width and height range. Therefore, even in that portion, the outer shape of the distribution chamber 6 can be made to fall within the range of the width and height of the throttle body mounting flange 13.

Note that in the above embodiment, the first opening 14 ₁
On the side opposite to the intake inlet 11, the cross-sectional area of the distribution chamber 6 is reduced by reducing its width, but the height of the distribution chamber 6 is formed so as to gradually become lower. You can also do it. Further, the cross-sectional area of the portion may be reduced by gradually changing the cross-sectional shape of the portion into a circular shape or the like.

(Effects of the invention) As is clear from the above description, according to the invention, a cylindrical distribution chamber having a circular intake inlet formed on one end surface, In an intake manifold including a plurality of open intake pipes, the cross-sectional area of the distribution chamber gradually expands from the intake inlet to the vicinity of the opening position of the first intake pipe closest to the intake inlet. , beyond the opening position of the first intake pipe, the flow rate of the intake air flowing inside the distribution chamber gradually decreases as it moves away from the intake inlet. It becomes smaller in the vicinity, and the intake air is reliably distributed to the first intake pipe, and the intake air is also forced into the intake pipe that opens at a position away from the intake inlet. Therefore, an intake manifold with high distribution efficiency can be obtained.

Furthermore, since the cross-sectional shape of the distribution chamber near the opening position of the first intake pipe where the cross-sectional area is maximum is approximately square, the cross-sectional area can be increased without increasing the width and height of the distribution chamber. This allows the entire intake manifold to be made compact.

In addition, the cross-sectional shape of the distribution chamber smoothly changes from a circular shape to a nearly square shape from the intake inlet to the vicinity of the opening position of the first intake pipe, resulting in a single-barrel type with good responsiveness in all operating ranges. This makes it possible to prevent sudden changes in flow velocity from occurring in the flow of intake air while using the same throttle body.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway plan view showing an embodiment of the intake manifold according to the present invention, Fig. 2 is a partially cutaway rear view of the intake manifold, and Fig. 3 is an intake intake introduction of the intake manifold. The side views seen from the mouth side, Figures 4A and B are respectively A- in Figure 1.
FIG. 5, a vertical cross-sectional view of the distribution chamber of the intake manifold taken along lines A and B--B, is a schematic side view, partially cut away, of the engine with the intake manifold. 1...Engine body, 4...Intake port, 5...
...Intake manifold, 6...Distribution chamber, 7,7
₁ , 7 ₂ , 7 ₃ , 7 ₄ ... Intake pipe line, 11 ... Intake inlet, 12 ... Throttle body, 12a ... Throttle valve, 12b ... Opening, 14 ₁ , 14 ₂ , 14 ₃ ,
14 ₄ ...Aperture.

Claims (1)

[Claims for Utility Model Registration] A cylindrical distribution chamber 6 in which a circular intake inlet 11 connected to a single barrel type throttle body 12 is formed on one end surface; In an intake manifold for a multi-cylinder engine, the intake manifold for a multi-cylinder engine includes a plurality of intake pipes 7 ₁ to 7 ₄ which are opened in parallel in order and whose other ends are connected to the intake port 4 of the engine main body 1; The shape smoothly changes from a circular shape to a substantially rectangular shape while increasing the cross-sectional area from the intake inlet 11 to the vicinity of the opening ₁₄₁ of the first intake pipe ₇₁ closest to the intake inlet 11. At the same time, on the opposite side from the opening ₁₄₁ position of the first intake pipe ₇₁ , the cross-sectional area thereof gradually decreases as the distance from the intake inlet 11 increases. manifold.