JPH0543215Y2 - - Google Patents

Description

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

[Prior Art] As disclosed in Japanese Utility Model Application No. 55-59119 and Japanese Utility Model Application No. 55-163422, a silencer for an internal combustion engine has a cylindrical housing with a plurality of cavities or chambers formed by partition plates. The exhaust gas from the inlet pipe is guided to a predetermined chamber, then sequentially guided from chamber to chamber, detoured to the starting end side chamber, turned back from the starting end side chamber, and guided to the outlet pipe. Since the direction of the exhaust flow changes in this starting end side chamber, a U-shaped pipe is provided, which promotes a smooth flow of exhaust gas and essentially lengthens the exit pipe to attenuate the high frequency components of the exhaust sound. Stay in. In other words, the relay pipe and the outlet pipe do not communicate in an open state in the chamber on the starting end side, but the relay pipe and the outlet pipe are connected by a U-shaped pipe in the chamber on the starting end side, so the passage of the outlet pipe is long. Therefore, the exhaust sound cannot be effectively attenuated using the starting end side chamber.

As mentioned above, silencers for automobile internal combustion engines use a chamber to attenuate exhaust noise, but especially in the case of automobile internal combustion engines, noise must be silenced over a wide frequency band, so Generally, a number of chambers inside the silencer housing are combined to allow exhaust air to pass through. When many rooms are partitioned inside the housing,
Due to constraints such as the length of the tube and the strength of the housing, the exhaust must be reversed inside the housing, and if the exhaust directly collides with the partition plate at the turning point, a vortex is generated in the chamber, reducing the flow velocity. , the exhaust pressure of the engine increases.

[Problems to be solved by the invention] Therefore, in view of the above-mentioned problems, the purpose of the present invention is to provide an internal combustion engine that can reduce the increase in exhaust pressure due to fluid resistance inside the muffler without reducing the silencing effect. The purpose of this invention is to provide a silencer for

[Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention is such that a plurality of chambers are divided by partition plates inside a housing whose both ends are closed, and a relay is used to communicate the predetermined chambers with each other. A pipe is arranged inside, an inlet pipe communicating with a predetermined chamber is provided on one end side, an outlet pipe communicating with the starting end side chamber is provided on the other end side, and both ends are aligned coaxially with the relay pipe and the outlet pipe in the starting end side chamber. This is a U-shaped tube connected.

[Operation] Utilizing the difference in the characteristics of exhaust gas and sound waves, the exhaust gas is guided to the U-shaped pipe 16 by the inertial force of the exhaust gas, and the exhaust gas is reversed (directed) without causing an increase in exhaust pressure.

The exhaust from the inlet pipe 13 diffuses and attenuates the sound waves in each chamber of the housing 2. In particular, housing 2
Since the relay pipe 15 and the outlet pipe 17 are open to the chamber on the starting end side, the sound waves are radiated and diffused here as well and are attenuated. At the same time, a phase difference occurs in the sound waves due to a path difference between the sound path that detours around the U-shaped pipe 16 and the sound path that goes directly from the relay pipe 15 to the outlet pipe 17, and the exhaust sound is attenuated.

The exhaust flow changes direction from the relay pipe 15 through the U-shaped pipe 16 that is coaxial with this outlet, and then heads toward the outlet pipe 17 that is coaxial with this outlet, so the fluid resistance is small.
Increase in exhaust pressure is suppressed.

[Embodiment of the invention] As shown in FIG. 1, both ends of the housing 2, which is a cylinder having a circular or predetermined cross section
It is closed by end plates 3, 4, and partition plates 5, 6, 7 are arranged inside to form a plurality of chambers 8, 9, 1.
0 and 12 are divided. An inlet pipe 13 is connected to the starting end of the housing 2, and an outlet pipe 17 is connected to the terminal end. The inlet pipe 13 passes through the end plate 3 and the partition plates 5, 6 and communicates directly with the chamber 10. This inlet pipe 13
A tube 14 arranged coaxially with is supported through the partition plate 7,
The chamber 10 and the chamber 12 are communicated with each other. The outlet pipe 17 is supported through the partition plates 5, 6, 7 and the end plate 4, and communicates with the chamber 8 on the starting end side. A relay pipe 15 is supported through the partition plates 5 and 6, and thereby the chamber 10 and the chamber 8 are communicated with each other. Preferably, a restriction 19 is formed at the outlet end of the relay pipe 15 which projects into the chamber 8 .

A U-shaped tube 16 is coupled to the outside of the end plate 3. One end 16a of the U-shaped tube 16 protrudes into the interior of the chamber 8 and is coaxially aligned with the relay tube 15. The other end 16b of the U-shaped tube 16 protrudes into the interior of the chamber 8 and is coaxially aligned with the outlet tube 17.

As shown in FIG. 2, the U-shaped tube 16 provided outside the housing 2 is provided with a large number of small holes 24, and its outer circumferential side is covered with a sound deadening material 21. Specifically, as shown in FIG. 3, the U-shaped tube 16 is wrapped with a sound deadening material 21, covered with a pair of cover plates 22 each having a semicircular cross section, and the flanges 23 on both sides are overlapped with each other, and bolts, etc. are combined by

Next, the operation of the silencer for an internal combustion engine according to the present invention will be explained. The exhaust air from the engine enters the chamber 10 via the inlet pipe 13, where the sound waves are diffused into the chamber 10 and attenuated. A strong exhaust flow passes through pipe 14 to chamber 1.
2, the pulsating flow (strength and weakness of the flow) is alleviated in the chamber 12, and the sound pressure of the exhaust sound is attenuated. In this way, disturbances in the exhaust flow in chamber 10 are attenuated by the damping effect of chamber 12, and the exhaust gas is diverted in chamber 10 and flows into relay pipe 15.

In the relay pipe 15, the chamber 9 surrounding it particularly attenuates high frequency components of the exhaust sound. The exhaust gas from the relay pipe 15 enters the chamber 8, but is throttled by the throttle 18 to increase the flow velocity, and most of it flows into the U-shaped pipe 16. However, since the relay pipe 15 and the U-shaped pipe 16 are separated by the chamber 8 on the starting end side, the exhaust sound is also diffused and attenuated here.

The exhaust gas smoothly changes direction through the U-shaped pipe 16 and returns to the chamber 8 again. Here, too, the sound waves detoured together with the exhaust air are diffused into the chamber 8 and attenuated. Exhaust gas is discharged to the outside through coaxially arranged outlet pipes 17. Outlet pipe 17
is a long one that directly communicates the chamber 8 on the starting end side of the housing to the outside, and the chambers 9 and 1 surrounding this are long ones.
0 and 12, the high frequency components of the exhaust sound with strong directivity are attenuated.

As described above, the exhaust gas that enters the housing 2 from the inlet pipe 13 is eased from turbulence in the chamber 10 by the buffering effect of the chamber 12, so it smoothly changes direction and enters the relay pipe 15, where it is relayed. Since the exhaust gas coming out of the pipe 15 is smoothly directed to the outlet pipe 17 by the action of the U-shaped pipe 16, there is little fluid resistance and an increase in exhaust pressure is suppressed.

The exhaust sound is not only diffused in the chamber 10 but also diffused in the chamber 8 to the end of the relay pipe 15, the end of the outlet pipe 17,
Since both ends of the U-shaped tube 16 are separated, the chamber 8
However, the exhaust noise is sufficiently diffused and attenuated. U-shaped tube 16
In this case, the highly directional high frequency component of the exhaust sound is U.
The sound passes through the small hole 24 of the tube 16 and hits the sound deadening material 21, where it is attenuated.

As described above, since the exhaust gas flows smoothly without resistance at the direction change section, an increase in exhaust pressure due to a decrease in speed is suppressed. In particular, since both ends of the U-shaped tube are in open communication with the chamber on the starting end side of the housing, at the terminal end of the relay tube and both ends of the U-shaped tube, sound waves are diffused into the chamber on the starting end side, and at the same time, the U-shaped tube By appropriately determining the length of the pipe, it is possible to reduce the sound pressure level by causing the sound waves that go directly from the relay pipe to the outlet pipe to interfere with the sound waves that have bypassed the U-shaped pipe.

[Effects of the invention] As described above, the invention divides a plurality of chambers inside a housing closed at both ends with partition plates,
A relay pipe that communicates the predetermined chambers with each other is arranged inside, an inlet pipe that communicates with the predetermined chamber is provided on one end side, an outlet pipe that communicates with the starting end side chamber is provided on the other end side, and the relay pipe and the starting end side chamber are provided. A U-shaped pipe is connected to the outlet pipe with both ends lined up coaxially.Especially when the exhaust gas changes direction from the inlet pipe to the relay pipe, the turbulence of the exhaust gas is suppressed by the buffering effect of the chamber on the end side, and the exhaust gas is flows smoothly, and only the exhaust noise is diffused and attenuated. In addition, since both ends of the U-shaped pipe connected to the starting side chamber of the housing are open to the starting side chamber and are placed coaxially with the relay pipe and the outlet pipe, the exhaust noise is attenuated by diffusion to the starting side chamber. can get. Since the exhaust gas flows smoothly from the relay pipe to the outlet pipe via the U-shaped pipe, fluid resistance is small and an increase in exhaust pressure is suppressed.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view showing a schematic structure of a muffler for an internal combustion engine according to the present invention, FIG. 2 is an enlarged sectional view of the same U-shaped tube, and FIG. 3 is a front sectional view of the U-shaped tube. 2... Housing, 5, 6, 7... Partition plate,
8, 9, 10, 12...chamber, 13...inlet pipe, 1
5... Relay pipe, 16... U-shaped tube, 17... Outlet pipe, 19... Throttle, 21... Sound deadening material, 24... Small hole.

Claims (1)

[Claims for Utility Model Registration] (1) A plurality of chambers are divided by partition plates inside a housing that is closed at both ends, and a relay pipe is arranged inside to communicate between the predetermined chambers, and one end of the housing is closed. It is characterized in that an inlet pipe communicating with a predetermined chamber is provided, an outlet pipe communicating with a starting end side chamber is provided on the other end side, and a U-shaped pipe is connected to the starting end side chamber, both ends of which are aligned coaxially with the relay pipe and the outlet pipe. Silencer for internal combustion engines. (2) The silencer for an internal combustion engine according to claim (1) of the utility model registration, which is provided with a throttle on the outlet side of the relay pipe. (3) The silencer for an internal combustion engine according to claim (1), which has a U-shaped tube with a small hole and whose outer periphery is covered with a sound deadening material.