JPH0424090Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a muffler for an internal combustion engine.

[Prior Art] As shown in FIG.
A chamber 8 is formed outside the porous tube 4 by penetrating and supporting the porous tube 4 having a large number of holes 5 and 6, and a partition plate 7 is attached to the middle portion of the porous tube 4. Entrance 4a
The exhaust gas flowing in from the chamber flows through the hole 5 to the chamber 8.
The exhaust gas is discharged from the holes 6 on the downstream side of the partition plate 7 of the porous pipe 4.
It flows into the inside of the porous pipe 4 and flows to the outlet 4b.

The exhaust gas easily flows out from the upstream hole 5 of the perforated pipe 4 to the chamber 8, but from the chamber 8 to the downstream hole 6 of the perforated pipe 4.
When flowing into the pipe, due to blowback of the flow inside the pipe,
At the hole 6, the flow entering the tube and the flow exiting the tube may collide. As mentioned above, the holes 6 of the perforated tube 4
Since the flow path resistance is large, even if the number of holes 6 is increased, the exhaust flow is not improved much, and air flow noise is generated due to blowback to the porous pipe and interference of the exhaust flow at the holes 6.

In the silencer disclosed in Utility Model Application Publication No. 58-122725,
By providing an inclined surface on the edge of the hole in the porous tube,
This improves the flow of exhaust gas into the perforated pipe, but the problem is that the processing of the perforated pipe is extremely complicated and time-consuming.

[Problems to be Solved by the Invention] In view of the above-mentioned problems, an object of the present invention is to provide a muffler for an internal combustion engine that has a simple structure, low flow resistance, and excellent muffling performance.

[Means for solving the problem] In order to achieve the above object, the configuration of the present invention is such that a perforated pipe communicating with an exhaust pipe is supported through both end walls of the outer cylinder, and a partition plate 7 is fitted in the middle of the perforated pipe. The large-diameter end of the throttle tube is fitted and fixed to the part downstream of the partition plate of the perforated pipe, the downstream side of the throttle tube is narrowed to a small diameter, and the part upstream of the large-diameter end of the throttle tube is fitted and fixed. The porous pipes on the downstream side are arranged so that the number of holes is approximately the same.

[Function] On the downstream side of the partition plate of the porous tube, the exhaust gas that enters the interior from the chamber of the outer cylinder through the holes of the porous tube increases its flow velocity in the throttle tube and flows toward the outlet. The throttle tube suppresses blowback from the outlet, and the static pressure inside the porous tube is lowered at the outlet of the throttle tube, so the exhaust from the chamber of the outer cylinder is controlled by the porous tube installed outside the throttle tube. It is smoothly sucked into the hole.

[Embodiment of the invention] As shown in Fig. 1, the silencer according to the invention has the following features:
A porous tube 4 having an inlet 4a and an outlet 4b is inserted into the outer tube 2.
The end plate 3 of
is formed. A partition plate 7 for closing the porous pipe 4 is fitted and fixed in the middle portion of the porous pipe 4, and a large number of holes 5 are provided on the upstream side of the partition plate 7, and a large number of holes 6 are provided on the downstream side of the partition plate 7.

As shown in FIG. 2, according to the present invention, the perforated tube 4 is provided with a throttle tube 9 on the outlet side having the holes 6. The large diameter portion 10 at the proximal end of the throttle tube 9 is fitted and fixed to the porous tube 4 . It is preferable to position the throttle tube 9 so that the number of holes 6 on the upstream side and the downstream side of the large diameter portion 10 of the multi-hole tube 4 is approximately the same in terms of the suction effect of the throttle tube 9 and the exhaust flow rate.

It is preferable that the tip edge or downstream edge 9a of the throttle tube 9 be longer than the hole 6 on the most downstream side by a length L. In addition, the cross-sectional area A2 of the tip of the throttle tube 9 is
Assuming that the cross-sectional area of the porous tube 4 is A1, the total area of the holes 5 is S1, and the total area of the holes 6 is S2, it is preferable to set the value expressed by the following formula.

A2=A1/(S1+S2) The present invention has the above-described configuration, so that the exhaust gas flowing out from the hole 5 on the upstream side of the partition plate 7 of the perforated pipe 4 into the chamber 8 is transferred from the hole 6 of the perforated pipe 4 to the upstream side of the throttle pipe 9. It flows into the inside of the porous pipe 4 by dividing into a side and a downstream side. Squeezing tube 9
and flows to the exit.

Exhaust gas flowing into the upstream side of the throttle tube 9 from the hole 6 of the porous tube 4 is throttled at the end of the throttle tube 9 to increase the flow velocity. Since the static pressure at the end of the throttle tube 9 is lower, the chamber 8
The exhaust gas is sucked into the porous tube 4 through the hole 6 on the outside of the throttle tube 9.

The flow path resistance of the porous pipe 4 is significantly reduced by the suction effect of the throttle pipe 9, and the disturbance of the exhaust flow due to blowback and the generation of airflow noise are reduced.

In the embodiment described above, a portion of the hole 6 of the perforated tube 4 is blocked by the large diameter portion 10 of the throttle tube 9, and the exhaust flow is disturbed at the edge 12.

In the embodiment shown in FIG. 3, no disturbance of the exhaust flow at the edge 12 occurs. A large diameter part 10 of the throttle tube 9 is extended to the partition plate 7, and a large number of holes 6b are provided in the large diameter part 10. In order to eliminate the misalignment between the hole 6b of the throttle tube 9 and the hole of the multi-hole tube 4, as shown in FIG.
a is provided in the porous tube 4. The chamber 8 and the interior of the porous tube 4 are substantially communicated through the holes 6b. Holes 6 are also provided in the perforated tube 4 on the outer peripheral side of the throttle tube 9.

In the embodiment shown in FIG. 5, the outer cylinder 2 is provided with partition plates 15 and 16 inside to partition chambers 21, 22, and 23. One end wall 3 is provided with an inlet 3a,
The porous pipe 4 is supported through the partition plates 15 and 16 and the other end wall 3. The porous tube 4 is provided with a hole 6 in a portion facing the chamber 23, and a throttle tube 9 is fitted inside the porous tube 4. The large diameter portion 10 of the throttle tube 9 is fitted and fixed to the portion of the porous tube 4 facing the chamber 22.

In this embodiment, a part of the exhaust gas that enters the chamber 21 from the inlet 3a enters the perforated pipe 4, and the remaining exhaust gas enters the chamber 22 through the hole 25 of the partition plate 15.
It enters the chamber 23 through the hole 26 of the tube, and from the chamber 23 it enters the inside of the porous tube 4 through the hole 6 of the porous tube 4. The exhaust gas entering the porous tube 4 from the chamber 21 is throttled by the throttle tube 9 to increase its speed, so that the exhaust gas from the chamber 23 is sucked out into the porous tube 4 through the hole 6.

[Effects of the invention] As described above, in the present invention, a perforated pipe communicating with an exhaust pipe is penetrated and supported on both end walls of the outer cylinder, a partition plate 7 is fitted and fixed in the middle of the perforated pipe, and the partition plate of the perforated pipe is fixed. The large-diameter end of the throttle tube is fitted and fixed to the part downstream of the throttle tube, and the downstream side of the throttle tube is narrowed to a small diameter, so that the holes in the perforated tube upstream and downstream of the large-diameter end of the throttle tube are approximately equal to each other. The exhaust gas inside the outer cylinder is separated into the upstream side and the downstream side of the throttle tube at the downstream side of the partition plate of the perforated tube, and flows into the inside of the perforated tube. In particular, due to the suction effect caused by the increased flow velocity of the exhaust flow passing through the throttle pipe, the exhaust gas on the downstream side flows smoothly between the porous pipe and the throttle pipe, improving the flow of the exhaust flow and eliminating exhaust blowback. This also reduces airflow noise caused by turbulence in the exhaust flow.

The present invention can be configured by simply fitting and fixing a throttle tube inside a perforated tube similar to the conventional example, and is easy to process and assemble.It has low flow resistance and excellent noise reduction performance at a small cost. We can provide silencers with

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional view showing the schematic structure of a silencer for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is a side cross-sectional view of a perforated pipe in the same muffler, and FIG. Embodiment 2 A cross-sectional side view of a perforated pipe in a muffler for an internal combustion engine according to the second embodiment, FIG. 4 is a side view showing the relationship between the holes in the perforated pipe and the holes in the throttle pipe, and FIG. 5 is a third embodiment of the present invention. FIG. 6 is a side sectional view showing a schematic structure of a muffler for an internal combustion engine according to the present invention, and FIG. 6 is a sectional side view showing a conventional general muffler for an internal combustion engine. 2... Outer cylinder, 3... End wall, 4... Porous pipe, 5,
6, 6a...hole, 7...partition plate, 9...throttle tube.

Claims (1)

[Scope of utility model registration request] A perforated pipe communicating with an exhaust pipe is supported through both end walls of the outer cylinder, and a partition plate 7 is fitted and fixed in the middle of the perforated pipe.
The large-diameter end of the throttle tube is fitted and fixed to the part downstream of the partition plate of the perforated tube, the downstream side of the throttle tube is narrowed to a small diameter, and the porous tube is connected to the upstream and downstream sides of the large-diameter end of the throttle tube. A silencer for an internal combustion engine, characterized in that the number of holes in the pipes are arranged to be approximately the same.