JPS63223319A - Intake device for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the charging efficiency of intake air by providing many recess parts on the inside surface of a downstream end of an intake pipe and a bending part on the inside surface of the peripheral wall of an intake port respectively, and thereby generating a static vortex in each recess part to reduce the intake resistance of the intake air. CONSTITUTION:An intake device is composed of an intake pipe 1, a siamese port 2 formed of intake ports 3 communicating with the intake pipe 1, and intake valves 5 provided in the intake ports 3. In this case, the downstream end 1a of the intake pipe 1 and a bending part 10a on the peripheral wall 10 of the siamese port 2 are formed with many recess parts 11 respectively, for instance in a zigzag shape. A mixture flow along the pipe wall of the intake pipe 1 is therefore caused to flow into each recess part 11 to generate a static vortex C there. Thus the mixture flow is guided along the static vortex to prevent its separation, and drawn into the intake valve 5 in a laminar flow. Consequently, since a mixture flow passage is never throttled, the intake air can be effectively charged even through the intake pipe 1 formed into small bore.

Description

[Detailed description of the invention] [Industrial use branch]

The present invention relates to an intake device for an internal combustion engine, and more particularly to an intake passage Hittia structure that reduces intake resistance in an air-fuel mixture intake passage. ■Prior art] Conventionally, in a two-valve intake power type internal combustion engine used as an automobile engine, or in an internal combustion engine of the type that supplies air-fuel mixture to multiple cylinders from one intake pipe, each intake port is made into a Siamese style. For example, JP-A-58
The prior art of Japanese Patent No.-150025 is known. In this type of engine, the air-fuel mixture that has flowed through one intake pipe is divided into two parts at the Siamese-shaped intake port.
The intake port has a large shape and can be divided into two types: straight and curved. 3 and 4 are examples of straight intake ports. In the figure, reference numeral 1 is a large-diameter intake pipe for inhaling the air-fuel mixture, and 2 is a Siamese port consisting of intake ports 3, 3 connected to the intake pipe 1 with almost no change in diameter. 4 is formed at an acute angle. Each intake port 3, 3 is provided with an intake valve 5. Furthermore, code 6
is a cylinder, 7 is an exhaust port, and 8 is an exhaust valve. In this shape of intake passage, the air-fuel mixture flows in a laminar flow as shown by arrow A, which reduces the engine's intake resistance and increases output, but it also increases the size of the engine and generally increases the diameter of the intake pipe. If there is a large amount, it is difficult to utilize the inertial supercharging of the air-fuel mixture, so the low-speed torque is low. Especially in the case of commercially available cars, there is a tendency for more emphasis to be placed on the compactness of the engine and the large amount of low-speed torque.
A curved suction passage, which will be described next, is often employed. Examples of curved intake ports are shown in FIGS. 5 and 6. In this type of intake port, the peripheral wall 1 of the Siamese port 2
0 has a smoothly curved shape, and the branch part 4 that branches into each intake port 3, 3 is close to the intake valve 5, 5 and has a smooth curved shape, making the overall size smaller. ing. Therefore, since the engine is formed into a compact engine and an intake inertia effect is obtained, there is an advantage that low-speed torque can be easily improved.

[Problems to be solved by the invention]

However, the air-fuel mixture flowing through the intake port having the shape shown in FIGS.
occurs, and the air-fuel mixture separates at the bending portions 10a and 10b. There is a problem in that this stationary vortex B spreads and the flow path through which the laminar flow A passes narrows, increasing suction resistance. The present invention has been made in view of these points, and it reduces the intake resistance by providing a concave part for static vortex generation in the inflection part of the intake pipe and intake port, and improves internal combustion through an intake system that can obtain an inertial effect. It is an object of the present invention to provide an intake device for an internal combustion engine that makes it possible to improve the filling efficiency of intake air into the engine.

[Means to solve the problem]

In order to achieve the above object, the present invention comprises an intake pipe for intake of a mixture, a Siamese port consisting of two intake ports connected to the intake pipe, and an intake valve provided at each intake port. In the internal combustion open intake device, a large number of recesses are provided on the inner surface of the downstream end of the intake pipe and on the inner surface of the peripheral wall of the intake port, at curved portions where a fluid separation phenomenon occurs. ing.

[For production]

Based on the above configuration, when supplying the air-fuel mixture to the internal combustion engine, the air-fuel mixture flow that has flowed through the intake pipe is located on the inner surface of the downstream end of the intake pipe and on the inner surface of the peripheral wall of the Siamese port, at the bending part where the fluid causes a separation phenomenon. A small stationary vortex is generated in the recess provided in the. Therefore, the mixed air flow continues along the circumferential wall of the Siamese port in a laminar flow state without causing separation due to the influence of these many stationary vortices, and is sucked into the cylinder from the intake valve. Therefore, the air-fuel mixture flow path is not restricted, making it possible to reduce suction resistance.

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. Note that two parts of members that are the same or equivalent to those of the conventional example will be described using the same reference numerals. 1 and 2 show the structure of an intake port according to the present invention applied to a two-valve internal combustion engine, where 1 is an intake pipe, and 2 is an intake port 3 connected to the intake pipe 1. It is a Siamese port consisting of
The branch portion 4 is formed into a smooth curve. Downstream end 1a of intake pipe 1 and peripheral wall 1 of Siamese port 2
The inflection portion 10ajOb of 0 has a large number of concave portions ii, ii
... are provided, for example, in a staggered manner. Furthermore, each intake port 3.3 is fitted with an intake valve 5,5. With the above configuration, the mixture flow along the pipe wall of the air-fuel mixture flowing through the intake pipe 1 flows into the recesses 11, 11, . . . when passing through the recesses 11, 11, .
A stationary vortex C2C... is generated at i, ii.... Since the air mixture flows along the stationary vortex C,
The downstream end 1a of the intake pipe 1 and the bending portions 10a and 10b of the Siamese port 2 do not separate, forming laminar flow holes and being sucked into the intake valves 5, 5. Therefore, the air-fuel mixture flow path is not constricted within the downstream end 1a of the intake pipe 1 and the Siamig port 2, so even if the intake pipe 1 is thinner than the conventional one, the air-fuel mixture is sufficiently distributed to the cylinder 7. is inhaled. In the above embodiment, an example is shown in which air is taken into a two-valve type internal combustion engine, but it can also be used as an intake passage that takes air into two different cylinders. Further, the size of the recess and its position are appropriately set depending on the type of internal combustion engine and the like.

【Effect of the invention】

As described above, according to the present invention, a large number of recesses are provided at the inflection parts where fluid separation occurs on the inner surface of the downstream end of the intake pipe and the inner surface of the peripheral wall of the intake port. Therefore, at the bending part of the intake pipe and intake port,
It is possible to prevent the flow path from being constricted due to the fluid separation phenomenon. Furthermore, the intake resistance is reduced by optimizing the flow, thereby improving the filling efficiency of intake air into the internal combustion engine and increasing the output. Furthermore, since an intake pipe with a small diameter can be used, the effect of inertial supercharging can be easily obtained, and the engine can be made more compact.

[Brief explanation of drawings]

'$1 Figure is a plan view showing one embodiment of the inhalation device according to the present invention, Figure 2 is a side sectional view, Figure 3 is a plan view showing a linear intake port, and Figure 4 is a side sectional view of the same. FIG. 5 is a plan view showing a conventional curved intake port, and FIG. 6 is a sectional view of the same side. DESCRIPTION OF SYMBOLS 1... Intake pipe, 1a... Downstream end, 2 River Siamese port, 3... Intake port, 4... Branch part, 5...
...Intake valve, 10...Surrounding wall, 10a, 10b...
Inflection part, 11... concave part. Patent Applicant: Fuji Heavy Industries Co., Ltd. Agent Patent Attorney: Jundo Kogyo, Patent Attorney: Susumu Murai Figure 1 Figure 2 Figure 3 Figure 5 Figure 4 Δ Figure 6

Claims (1)

[Claims] In an intake system for an internal combustion engine, the intake system includes an intake pipe for intake of a mixture, a Siamese port consisting of two intake ports connected to the intake pipe, and an intake valve provided at each intake port. An intake device for an internal combustion engine, characterized in that a large number of recesses are provided on the inner surface of the downstream end of the pipe and on the inner surface of the peripheral wall of the intake port, at curved portions where fluid separation occurs.