JPS5851406Y2 - Internal combustion engine intake system - Google Patents

Description

[Detailed explanation of the invention] This invention is installed on small snowmobiles, outboard motors, tillers, etc.
This invention relates to an improvement in an intake system for an internal combustion engine that is not equipped with an air purification device.

Generally, small snowmobiles, outboard motors, and power tillers travel in areas with little dust, so the carburetors installed in the internal combustion engines installed in these vehicles are used without air purification devices. Since pulsating waves of intake air are generated in the vicinity of the intake port of the carburetor, a whistle-like intake sound is generated (1), which has the drawback of increasing noise.

Therefore, in order to muffle the noise caused by the pulsating waves of the intake air, an expansion chamber is installed near the intake port of the carburetor, and the pulsating waves of the intake air interfere with each other to muffle the intake noise, but this method does not have a sufficient noise-cleaning effect. The problem was that I couldn't get it.

This idea was devised in view of the above circumstances, and its purpose is to effectively muffle the intake noise generated near the intake port of the carburetor, be lightweight and inexpensive, have a simple structure, and be easy to manufacture. An object of the present invention is to provide an intake system for an internal combustion engine that allows easy operation.

This invention will be explained below based on embodiments shown in the drawings.

First, an embodiment shown in FIGS. 1 and 2 will be described. In the figures, 1 is a carburetor installed in an internal combustion engine (not shown), and this carburetor 1 has an intake port 2. An opening at one end of a tube 4 made of a flexible material such as rubber and constituting an intake passage 3 is attached to the intake port 2 with a bolt 5 .

The other end of the tubular body 4 is bent downward, and the opening edge is fitted into an air exhaust lower of a cylindrical body 6 made of a blow-molded synthetic resin material such as polyethylene.

An expansion chamber 8 is formed inside the cylinder 6 and expands in an L-shape from the air exhaust lower. It is connected to the.

Fitting holes 9, 9 are formed in opposing sides of the cylinder 4, and these fitting holes 9, 9 are provided with side plates made of an elastic material such as rubber, which is softer than the material constituting the cylinder 6. 10,10
are fitted into the fitting holes 9, 9, respectively, and annular grooves 11.11 formed on the outer peripheries of these side plates 10, 10 correspond to the fitting holes 9, 9.
It is fitted into the inner periphery and fixed by joint pressure.

The side plate 1010 is provided with a plurality of air suction pipes 12.12 that protrude into the expansion chamber 8, and these air suction pipes 12.12 are integrally formed of the same material as the side plates io and io. .

The air suction pipes 12, 12 have inner end openings 12a.

12a are positioned to face each other, and open to the atmosphere through the outer end openings 12b, 12M'' and the measuring plate 10°10, so that external air is drawn into the expansion chamber 8.

To explain the operation of the intake system shown in FIGS. 1 and 2, when an internal combustion engine (not shown) is started, external air flows into the outer end opening 12b as shown by the arrow.

Air suction pipe 12 from 12b, expansion chamber B through 12 pipes
The air is then introduced into the air intake port 2 of the carburetor 1 via the air exhaust lower through the air intake passage 3.

The air flows while being constricted when passing through the air intake pipe 12, 12, and is diffused when flowing into the expansion chamber 8, so that an interference effect occurs on the pulsating waves during intake, and intake noise is muffled. Ru.

In this case, since the measuring plate 10 and the air suction pipe 12°12 are also made of soft elastic material, the vibration energy of the sound is transferred to the measuring plate 10 and the air suction pipe 12.
．． 12, the sound is muffled and less sound goes outside, improving sound insulation.

If the diameters and lengths of the air suction pipes 12.degree.

Further, FIGS. 3 and 4 show other embodiments of this invention, and 1' is a carburetor installed in an internal combustion engine (not shown).
This carburetor 1' has an intake port 2', and one end opening of a tube 4' constituting an intake passage 3' is attached to this intake port 2' with a bolt 5'.

The tubular body 4' and the other rigid parts are bent downward to form a cylindrical body 6', and the cylindrical body 6' and the tubular body 4' are integrally press-molded from a flexible material such as rubber. It is formed by

The mating surface 13 of the cylindrical body 6' is joined by a clip 14, and a reinforcing band 15 is provided in the circumferential direction on the inner surface of the approximately central portion of the cylindrical body 6', thereby changing the shape of the cylindrical body 6'. At the same time, an expansion chamber 8' is formed therein, and this expansion chamber 8' is connected to the intake port 2' of the carburetor 1' via the intake passage 3' of the tube body 4'. There is.

Fitting holes 9', 9' are formed in the opposing measuring parts of the cylinder 4', and measuring plates 10', 10' made of synthetic resin material are fitted into the fitting holes 9', 9', respectively. These side plates 10', 10' have a substantially triangular shape and are attached to the cylinder body 6.
The outer peripheries of these side plates io', io' are fitted into annular grooves 11', 11' formed in the inner peripheries of the fitting holes 9', 9', and are pressed into place by elastic pressure. Fixed.

The measuring plates 10', 10' are provided with a plurality of air suction pipes 12', 12' that protrude into the expansion chamber 8'.
', 10' are integrally formed of the same material.

The air suction pipes 12', 12' are positioned such that their inner end openings 12a', 12a' face each other, and their outer end openings 12b'.

12b' opens to the atmosphere through the side plates 10', 10', so that outside air can be drawn into the expansion chamber 8'.

Furthermore, a plurality of air suction holes 16, 16 are opened in the side plates 10', 10', and external air is sucked into the expansion chamber 8' from these air suction holes 16,16.

Further, 17° 17 is a projection provided on the inner surface of the cylinder 4' to guide the reinforcing band 15, and 18 is a reinforcement provided at a location where the expansion chamber 8' changes to the intake passage 3'. It is a ring.

To explain the operation of the intake device shown in FIGS. 3 and 4, when an internal combustion engine (not shown) is started, external air flows from the outer end openings 12b', 12b' to the air intake pipe 12' as shown by the arrows. .

12' into the expansion chamber 8', and further through the intake passage 3' to the intake port 2' of the carburetor 1'.

and an aerodynamic air intake pipe 12'. Since the air flows while being constricted when passing through the expansion chamber 8' and is diffused when flowing into the expansion chamber 8', interference occurs with the pulsating waves during intake, thereby muffling intake noise.

Also, the outside air is provided by the measuring plate 10'. 10' air intake hole 1
Since the air is also drawn into the expansion chamber 8' from the air pumps 6 and 16, this air also causes an interference effect, and the resistance to drawing air into the carburetor can be reduced.

Also in this case, the sound vibration energy is absorbed by the measuring plate 10' and the air suction pipes 12', 12', so that the sound deadening and sound insulation effects are improved.

Further, by making the diameters and lengths of the air intake pipes 12' and 12' different, the interference of pulsating waves can be effectively achieved over a wide range, and the effect of silencing intake noise can be further improved.

Note that this invention is not limited to constructing the tube and cylinder body with flexible or elastic materials, and even if only the measuring plate and air intake pipe are constructed of elastic materials, sound vibration energy will not be absorbed. A sound insulation effect can be expected.

It is preferable that the tube body and the cylindrical body are at least more rigid than the side plate and the air intake pipe, and in this way the cylindrical body can be protruded in a cantilever shape from the intake port of the carburetor to the measuring direction. In a case like the above embodiment, even if mechanical vibrations are transmitted, the strength is increased, so reliability is improved.

This idea has been described in detail above, and involves connecting a cylindrical body that forms an expansion chamber inside to the intake port of the carburetor via an intake passage, and inserting a fitting hole into the side of the cylindrical body. It is formed by fitting into a side plate made of an elastic material such as rubber, which is integrally provided with a plurality of air suction pipes that protrude into the expansion chamber.

Therefore, according to this device, since the intake air is contracted and expanded during the process of passing through the intake path, not only is the interference effect of the intake pulsating waves effectively performed, but also the energy of the pulsating waves is generated by the side plate made of elastic material and the air intake pipe. Because the air is absorbed and sound insulated, intake noise can be reduced.
・It becomes thinner.

Also, since the side plate and the air intake pipe are integrally molded, they can be attached to the side plate all at once, and since the side plate and the air intake pipe are made of an elastic material, in addition to the above-mentioned sound absorption and sound insulation effects, Since the side plate is elastically deformed when it is attached to the fitting hole of the cylindrical body, the attachment becomes easy and the sealing performance with the cylindrical body is improved.

In addition, since the side plate and air intake pipe can be easily removed and replaced, not only is maintenance and inspection easy, but the sound can be muted according to the output of the internal combustion engine by replacing the air intake pipe with a measuring plate of a different diameter and length. It has excellent effects such as being able to adapt to specific characteristics.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of this invention, with Figure 1 being a partially cutaway surface diagram, Figure 2 being a sectional view taken along line ■-■ in Figure 1, and Figure 3 and Fig. 4 show another embodiment of this invention, Fig. 3 is a partially cutaway surface diagram, and Fig. 4 shows the third
It is a sectional view along the IV-IV line of a figure. 1.1'...Carburizer, 2,2'...Intake port, 3゜3'...Intake passage, 6.6'...
... Cylindrical body, 8, 8'... Expansion chamber, 9, 9'.
...Fitting hole, 10,10'...Measuring plate, 1
1, 11'... annular groove, 12, 12'...
・Air intake pipe.

Claims (1)

[Scope of utility model registration request] A cylindrical body forming an expansion chamber inside is connected to the intake port of the carburetor via an intake passage, and a plurality of tubes protruding into the expansion chamber are inserted into fitting holes formed on the side of the cylindrical body. An intake device for an internal combustion engine characterized by an air intake pipe fitted into a side plate made of an elastic material such as rubber.