JPH0627787Y2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a silencer.

[Prior art]

Conventionally, in a muffler used for an internal combustion engine, as shown in FIG. 2, the rear portion of the inlet pipe 100 is branched into two pipes 101 and 102, and one of the branch pipes 101 is opened to a chamber in the chamber. The other branch pipe 102 is provided so as to penetrate the inside of the container and a small hole 103 is formed in the middle thereof, a switching valve 104 is provided at the branch portion, and the exhaust pipe 105 including the other branch pipe 102 is There is another one in which another exhaust pipe 106 is provided.

[Problems to be solved by the present invention]

By the way, in a muffler for an internal combustion engine, improvement of the muffling effect is required rather than improvement of the back pressure reduction effect at low engine speed and low load, and improvement of muffling effect is required at high engine speed and load. It is required to improve the engine output by improving the back pressure reducing effect.

Therefore, in the above conventional structure, the switching valve 10
Although the above-mentioned request is dealt with by the switching operation of 4, when exhaust mode is switched to the low back pressure mode, the exhaust noise suddenly increases, and there is a audible problem in terms of the feeling of riding in the actual vehicle. In addition, the exhaust gas may come out from only one of the two exhaust pipes 105 and 106, and in this case, there is a problem that it does not look good.

Then, this invention aims at proposing the silencer which can eliminate the said problem.

[Means for Solving the Problems]

In order to solve the above problems, the present invention divides the body into at least three chambers of a front chamber, an intermediate chamber, and a rear chamber, and a rear portion of the inlet pipe penetrates each chamber from the front chamber. And the second part that folds back the flow and penetrates each chamber again.
And a third penetrating portion that folds back the subsequent flow portion and penetrates each chamber, and is formed in a meandering shape, and further, the first penetrating portion located in the rear chamber and the third penetrating portion located in the intermediate chamber. Small holes for circulation are formed in the second penetrating portion and the third penetrating portion located in the front chamber, and an opening / closing valve that operates according to the rotating state of the engine is provided in each of the folding portions. It is characterized by that.

〔Example〕

 Next, an embodiment of the present invention shown in FIG. 1 will be described.

1 is a silencer, the outer shell of which is composed of a peripheral edge 1a and front and rear walls 1b, 1c. The interior of the container is divided into front chamber 4, middle chamber 5 and rear chamber 6 by partition walls 2 and 3. Reference numeral 7 denotes an inlet pipe, and the rear flow portion thereof is a first penetrating portion 8 which penetrates from the front wall 1b of the silencer 1 through the front chamber 4, the intermediate chamber 5, the rear chamber 6 and the rear wall 1c to the outside of the device, After that, the flow further folds back and again penetrates the rear chamber 6, the intermediate chamber 5, the front chamber 4 and the front wall 1b to the second penetrating portion 9 that goes out of the chamber, and further folds back to the front chamber 4, the intermediate chamber 5, and the rear chamber. It is formed in a meandering shape by the chamber 6 and the third penetrating portion 10 penetrating the rear wall 1c to the outside of the vessel, and the last flow portion is an outlet pipe 11. A small hole 12 is formed in the first penetrating portion 8 located in the rear chamber 6, a small hole 13 is formed in the second penetrating portion 9 located in the middle chamber 5, and a small hole 13 is formed in the third penetrating portion 10 located in the front chamber 4. Each small hole 14 is formed. The first folding part 15 and the second folding part 16 are butterfly type on-off valves, respectively.
17,18 are provided. The opening / closing valves 17 and 18 are controlled to open / close depending on the engine rotation state.
8 is closed, the first opening / closing valve 1
The opening / closing valve 7 opens and the second opening / closing valve 18 closes, so that both the opening / closing valves 17 and 18 open when the engine is running at high rotation speed and high load. Numerals 19 and 20 are inner pipes that connect each room.

In the present embodiment, when both the on-off valves 17 and 18 are closed at low engine speed and low load, the exhaust gas from the inlet pipe 7 flows into the rear chamber 6 inside the unit only through the small holes 12, and the inner pipe After passing through 19, it enters the intermediate chamber 5, through the inner pipe 20 and then into the front chamber 4, and flows into the pipe of the third penetration portion 10 through the small hole 14 and is discharged from the outlet pipe 11 to the outside of the device. Therefore, all the exhaust gas is silenced through all the chambers, and the silencing effect is enhanced.

Also, the first open / close valve when the engine rotates at medium speed and medium load
When 17 is opened and the second open / close valve 18 is kept closed at the same time, a part of the exhaust gas from the inlet pipe 7 flows out from the small hole 12 as described above, and the main flow of the exhaust gas is intermediate from the small hole 13. It enters the chamber 5, passes through the inner pipe 20 and the front chamber 4, flows into the pipe of the third penetration portion 10 through the small hole 14, and flows out of the device through the outlet pipe 11. Therefore, the main flow of the exhaust gas is short-circuited to the intermediate chamber 5 without passing through the rear chamber 6, and the silencing effect is less than that at the time of low rotation and low load, but the back pressure is reduced.

In addition, both open / close valves 17
When 8 is opened together, a part of the exhaust gas from the inlet pipe 7 flows out from the small holes 12 and 13 as described above, and the main flow of the exhaust gas meanders without entering the chambers 4, 5 and 6. Outlet pipe 15 flowing in one pipe
More out of the vessel. Therefore, the low, medium rotation, low,
The noise reduction effect is lower than that under medium load, but the back pressure reduction effect is higher.

[Effect of device]

As described above, according to the present invention, the noise reduction effect can be enhanced at low engine speed and low load, and the back pressure reducing effect can be enhanced at high engine speed and high load. Low rotation, low load to high rotation,
When shifting to a high load state, the muffling effect can be temporarily mitigated in the middle rotation and medium load states, so that the exhaust noise suddenly increases as in the conventional case, and the audibility on the real car side is reduced. You can prevent it from getting worse. In addition, the exhaust gas always flows out of the device through one exhaust pipe, which is attractive.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a side sectional view showing a conventional structure. 4 ... front chamber, 5 ... middle chamber, 6 ... rear chamber, 7 ... inlet pipe, 8 ... first penetrating portion, 9 ... second penetrating portion, 10 ... third penetrating portion , 12,13,14 …… Small hole, 17,18…
… Open / close valve

Claims (1)

[Scope of utility model registration request] 1. A container body is divided into at least three chambers of a front chamber, an intermediate chamber, and a rear chamber, and a rear flow portion of an inlet pipe is a first through portion penetrating each chamber from the front chamber and a rear flow portion. And a first penetrating portion that is formed in a meandering shape by a second penetrating portion that folds back and penetrates each chamber again, and a third penetrating portion that folds a subsequent flow portion and pierces each chamber. A through hole, a second through hole located in the intermediate chamber, and a third through hole located in the front chamber, each having a small hole for distribution formed therein,
Further, a silencer characterized in that an opening / closing valve which is operated depending on a rotating state of the engine is provided at each of the folding portions.