RU2241126C1 - Internal combustion engine muffler - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines.

SUBSTANCE: proposed muffler has cylindrical housing of elliptical cross section with three chambers formed by end face walls of housing and cross partitions, one of which is perforated, intake and exhaust branch pipes and intake and exhaust pipes with perforated sections connected coaxially with corresponding branch pipes, noise-absorbing chamber with noise-absorbing heat resistant packing made of porous material and arranged on perforated section of exhaust pipe. Intake and exhaust pipes have additional perforated sections. Additional perforated section on exhaust pipe is made after partition and is pointed to side opposite to intake pipe. Additional perforated section on intake pipe is displaced towards rear partition and is made in form of narrow sector in cross section of pipe pointed to exhaust pipe. Front partition is provided with perforated sections arranged symmetrically relative to larger axis of ellipse section of housing and displaced along its smaller axis to wall of muffler housing. Perforated section of rear partition is located around intake pipe. Noise absorbing chamber is furnished with protective tight casing in which noise-absorbing heat-resistant packing is placed.

EFFECT: improved efficiency of noise damping.

13 cl, 7 dwg

Description

The invention relates to mechanical engineering, in particular engine manufacturing, namely, to silencers of the exhaust noise of an internal combustion engine.

Known silencer for internal combustion engine (see, for example, AS USSR No. 1638323, class F 01 N 1/02, 01/18/89.), Comprising a housing with end walls, an inlet and outlet pipe, a central perforated pipe, connected to the nozzles, three chambers formed by a transverse partition and a casing covering the pipe in the area of the outlet pipe, the transverse partition is perforated, and a transverse plug is placed in the pipe in the plane of the partition.

The disadvantages of this design are the insufficient efficiency of damping exhaust noise over a wide range, due to the limited number of chambers of small volume, as well as the lack of damping of structural noise created by the body parts of the muffler.

In addition, the creation of increased active resistance when passing through an exhaust silencer adversely affects the power, economic and toxic characteristics of the engine.

Known silencer of the internal combustion engine (see, for example, AS USSR No. 1618898, class F 01 N 1/02, 07/04/88.), Comprising a housing with end walls, inlet and outlet pipes installed in the end walls transverse perforated partitions forming three chambers, the first pipe crossing the partitions and provided with an internal perforated section, and the second placed coaxially to the housing and provided with a perforated section placed between the partitions and placed in a casing forming an additional chamber.

The disadvantages of this design are the insufficient efficiency of damping exhaust noise over a wide range, due to the limited number of chambers of small volume, as well as the lack of damping of structural noise created by the body parts of the muffler.

The closest device of the same purpose to the claimed invention in terms of features is a silencer of the exhaust exhaust of an internal combustion engine (see, US patent No. 4610329, CL F 02 N 1/10 of 09/12/86), containing a cylindrical ellipse cross-sectional body with three cameras formed by the end walls of the casing and transverse partitions, one of the partitions being made of perforated, inlet and outlet pipes and coaxially connected inlet and outlet pipes with perforated sections, -rotating chamber comprising a sound absorption pad of porous refractory material disposed on the perforated discharge pipe portion, the film is interposed between the perforated portion of the perforated pipe and the heat-resistant sound-absorbing gasket, wherein zvukopoglaschayuschaya chamber arranged between the transverse partitions.

The specified silencer with broadband sound suppression due to the presence of an additional sound-absorbing chamber, allows to reduce the noise accompanying the exhaust gas stream at medium and high acoustic frequencies. The muffler has an effective damping of the aerodynamic noise of an exhaust gas stream emitted into the atmosphere without significant effects on power loss.

The disadvantages of this design is the low efficiency of damping structural noise generated by the body parts of the muffler, which affects the increase in the total noise of the exhaust and the car as a whole.

The technical result of the invention is to increase the efficiency of damping exhaust gas noise and structural noise generated by the body parts of the muffler while reducing power losses, and improving the economic and toxic characteristics of the engine.

The specified technical result in the implementation of the invention is achieved by the fact that in the known silencer of an exhaust of an internal combustion engine comprising a cylindrical body of an elliptical cross section with three chambers formed by the end walls of the body and transverse partitions, one of which is made of perforated, inlet and outlet pipes connected to them coaxially inlet and outlet pipes with perforated sections, a sound-absorbing chamber with heat-resistant packing of porous material, arranged laid on the perforated section of the exhaust pipe, said inlet and outlet pipes are provided with additional perforated sections, wherein the additional perforated section on the exhaust pipe is made behind the first baffle and faces in the opposite direction from the inlet pipe, and the additional perforated section on the inlet pipe is biased towards the rear baffle and made in the form of a narrow in cross-section of the pipe sector, facing the exhaust pipe, the front partition is provided with perforated sections, p positioned symmetrically with respect to the major axis of the ellipse section of the body, displaced along its minor axis to the wall of the silencer body, the perforated portion of the rear wall is placed around the inlet pipe, while the sound-absorbing chamber is provided with a protective hermetic casing, with sound-absorbing heat-resistant packing placed therein.

The total passage area of the holes of the perforated section of the inlet pipe in the second chamber exceeds the total passage area of the holes of the perforated section of the first and open cut of the inlet pipe of the third chamber.

The ratio of volumes V ₁ : V ₂ : V _{3 of the} first chamber to the second and third is expressed as 1: 3: 2.

Additional perforated sections on the inlet and outlet pipes are located in the second chamber.

The narrow sector of the additional perforated section on the inlet pipe is placed symmetrically with respect to the major axis of the ellipse section of the housing.

The narrow sector of the additional perforated section on the inlet pipe faces the protective sealed enclosure of the sound-absorbing chamber.

The front partition is provided with at least two perforated sections.

The perforated sections of the front partition are made with an increase in the number of openings to the wall of the silencer body.

The perforated portion of the rear wall is made with an increase in the number of holes to the exhaust pipe.

The end walls of the housing are made with U-shaped punching, covering partially inlet and outlet nozzles with a gap.

The sound-absorbing chamber may be partially located in the second and third chambers, while crossing the rear wall.

The outlet pipe may be elongated with a perforated portion over most of its length.

The sound-absorbing chamber can be placed behind the silencer body on the perforated section of the exhaust pipe.

Comparison of scientific, technical and patent documentation on the priority date in the main and related sections shows that the set of essential features of the claimed solution was not previously known, therefore, it meets the patentability condition of “novelty”.

Analysis of known technical solutions in the art showed that the proposed device has features that are not in the known technical solutions, and using them in the claimed combination of features makes it possible to obtain a new technical result, therefore, the proposed technical solution has an inventive step compared to the existing level technicians.

The proposed technical solution is industrially applicable, because can be manufactured industrially, efficiently, feasibly and reproducibly, therefore, meets the patentability condition "industrial applicability".

The invention is illustrated by drawings, where

figure 1 shows a longitudinal section (along the major axis of the ellipse) of the silencer of the exhaust noise of an internal combustion engine with a sound-absorbing chamber inside the silencer body;

figure 2 is a longitudinal section (along the major axis of the ellipse) of the muffler with a sound-absorbing chamber located behind the muffler;

figure 3 - diagram of the operation of the muffler indicating the flow of exhaust gases;

figure 4 is a section aa in figure 1;

figure 5 is a section bb in figure 1;

figure 6 is a section bB in figure 1;

Fig.7 is a design of the front and rear end walls of the housing increased stiffness.

The silencer of the exhaust of an internal combustion engine contains a cylindrical body 1 of an elliptical cross section with three chambers 2, 3, 4, formed by the end walls 5, 6 of the housing 1 and transverse front and rear perforated partitions 7, 8.

In parallel with the longitudinal axis of the silencer body 1, an inlet pipe 9 is placed in the front end wall 5, extending in the silencer body in the form of an inlet pipe 10 intersecting the front and rear baffles 7, 8 and ending with an open cut 11 in the third chamber 4. The inlet pipe 10 communicates with the first chamber 2 through the perforated section 12 having a total passage area of perforation:

S ₁ = (0.1-0.12) πD $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$ /4,

where D ₁ is the inner diameter of the inlet pipe 9 and the inlet pipe 10.

In parallel with the longitudinal axis of the silencer case 1, an exhaust pipe 13 is placed in the rear end wall 6, extending in the silencer case 1 in the form of an exhaust pipe 14 intersecting the front and rear partitions 7, 8 and ending with an open cut 15 in the first chamber 2.

On the exhaust pipe 14 (Fig. 1), in a section 16 with frequent and shallow perforations, a sound-absorbing chamber 17 with a sound-absorbing heat-resistant fine-fiber packing 18, for example, of basalt fiber or mineral wool, is located, the sound-absorbing chamber is equipped with a protective hermetic casing 19, in which the sound-absorbing casing is placed heat resistant pad 18.

The sound-absorbing chamber 17 in this case is partially located in the second and third chambers 3, 4, while crossing the rear partition 8.

The exhaust pipe 13 (Fig. 2) can be elongated with a portion 16 of frequent and shallow perforations over most of its length, while the sound-absorbing chamber 17 is located behind the silencer body 1 on the perforated section 16 of the exhaust pipe 13.

The total passage area of the perforated section 16 at the installation site of the sound-absorbing chamber:

S ₂ = (8-10) πД $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$ /4,

where D ₂ is the inner diameter of the exhaust pipe 13 and the exhaust pipe 14.

The inlet and outlet pipes 10, 14 are provided with additional sections of perforation. Additional perforated sections on the inlet and outlet pipes are placed in the chamber 3.

To increase the "mixing" of gases in the exhaust pipe and reduce the "axial effect" of the passage of the unmuffled component of the exhaust gases having a sound frequency, an additional perforated section 20 on the exhaust pipe 14 is made behind the first partition 7 and faces in the opposite direction from the inlet pipe 10.

The total passage area of the perforated section 20:

S ₃ = (4,5-5) πД $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$ /4,

where D ₂ is the inner diameter of the exhaust pipe 14.

The replenished perfused section 21 on the inlet pipe 10 is biased towards the rear baffle 8 and is made in the form of a narrow cross-section of the pipe 10 of the sector 22 (FIG. 4), facing the casing 19 of the sound-absorbing chamber 17 (FIG. 1) or the exhaust pipe 14 (FIG. 2), which are convex scattering screens. A narrow sector 22 of the additional perforated section 21 on the inlet pipe 10 is placed symmetrically with respect to the major axis of the ellipse section of the housing 1.

The total passage area of the perforated section 21:

S ₄ = (1.1-1.2) πD $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$ /4,

where D ₁ is the inner diameter of the inlet pipe 10.

The front wall 7 is provided with at least two perforated sections 23 (Fig. 5) located symmetrically with respect to the major axis of the ellipse section, offset along its minor axis to the inner contour of the silencer body 1. The perforated sections 23 of the front partition 7 are made with an increase in the number of openings to the wall of the silencer housing 1.

Total passage area of perforated sections 23:

S ₅ = (5.5-6.0) πD $\genfrac{}{}{0ex}{}{\text{2}}{\text{2}}$ /4,

where D ₂ is the inner diameter of the exhaust pipe 14.

The perforated section 24 of the rear wall 8 is placed around the inlet pipe 10 and is made with an increase in the number of holes to the exhaust pipe 14.

The total passage area of the perforated section 24:

S ₆ = (4.5-5.0) πD $\genfrac{}{}{0ex}{}{\text{2}}{\text{1}}$ /4,

where D ₁ is the inner diameter of the inlet pipe 10.

The ratio of volumes (Fig. 1) of the first chamber 2 to the second and third chambers 3, 4 is expressed as 1: 3: 2.

The end walls 5, 6 of the housing 1 (Fig.7) are made with U-shaped punching 25, covering with a gap partially inlet and outlet pipes 10, 14.

The muffler works as follows.

A gas stream of exhaust gases having high energy (temperature and pressure), in which sound waves of a wide frequency range propagate, through the pipe 9 enters the inlet pipe 10 (Fig.3). To reduce the pressure pulse of gas pressure on the body parts, the principle of gradual gas passage through the perforated section 12 into the chamber 2, the perforated section 21 into the chamber 3, and the open cut 11 into the chamber 4 were applied.

Part of the gases that passed into the chamber 4 through an open slice 11 of the inlet pipe 10, through the perforated section 24 of the rear baffle 8, enters the chamber 3, where it interacts with the flow of gases entering through the perforated section 21 of the inlet pipe 10.

Part of the gases entering the chamber 3 through the perforated section 21 meets a convex diffusing screen, which is used as a casing 18 of the sound-absorbing chamber 17 (Fig. 1) or an exhaust pipe 14 (Fig. 2), and is scattered, partially losing energy, and then having connected with the flow from the chamber 4, it partially enters the chamber 3 through the perforated sections 23 in the front partition 7 and then, interacting with the flow of gases passing through the perforated section 12 of the inlet pipe 10, passes through an open cut 15 into the exhaust pipe 14.

Part of the gases from the chamber 3 enters the exhaust pipe 14 through the perforated section 20, where it is connected to the gases that have passed through the open cut 15 of the exhaust pipe 14.

Since the holes of the perforated section 20 are made from one side of the exhaust pipe 14 and meet the gas stream passing through the open cut 15 at an angle, there is an additional gas turbulence when passing through the perforated section 16 of the exhaust pipe 14 and the noise level of medium and high frequencies is further reduced due to more active use.

Chambers 2, 3, 4 and the corresponding perforated sections 12, 21, open slice 11 (Figs. 1, 2) are designed and made as resonant low-frequency sound frequencies of 100-450 hertz. When passing exhaust gases from the inlet pipe 10 into the chambers 2, 3, 4, sound waves of the indicated frequency meet high resistance in their path and are reflected to the engine 25 (Fig. 3), thereby reducing the low-frequency noise of the exhaust gases and their exciting effect on the body parts .

The presented design of the silencer is aimed at reducing the radiation of structural noise generated by the body parts of the silencer by reducing the impact of exciting factors causing vibrations of the body parts of the silencer, namely:

smoothly reducing the impulse of gas-dynamic impact of the exhaust gases passing through the inlet pipe 10 to the body parts by uniformly distributing their release through the perforated section 12 into the chamber 2, the perforated section 20 into the chamber 3 and through the open cut 11 into the chamber 4;

creating resonant resistance for low-frequency oscillations of 100-450 hertz and the reflection of sound waves at the mentioned frequencies to the engine when exhaust gases pass through the perforated sections 12, 20 and the open cut 11 of the inlet pipe 10 (Fig. 3).

Thus, the vast majority of the exhaust gases passing through the perforated sections 12, 21 and the open cut 11 of the inlet pipe 10 into the chambers 2, 3, 4, retained the components with medium and high oscillation frequencies, having undergone some energy reduction due to friction during outflow through the holes perforated sections, and reduced the level of low-frequency components due to reflection.

A further reduction in the energy of the exhaust gases is achieved in the chamber 3 due to the direction of the perforated section 21 on the inlet pipe 10, facing the casing 19 of the sound-absorbing chamber (figure 1) or exhaust pipe 14 (figure 2), which are convex scattering screens.

The next factor in reducing the excitatory effect of exhaust gases on the silencer case 1 is the interaction of flows passing through the perforated section 24 in the partition 8 from the chamber 4 into the chamber 3 and through the perforated section 21 of the inlet pipe 10.

To reduce the effect of gas flows on the end wall 5 of the muffler, it is provided (Fig. 3) that gas flows in the chamber 2 interact through the perforated sections 23 of the partition 7 and enter through the openings of the perforated section 12 of the inlet pipe 10, while simultaneously reducing the resistance when turning the gases to the cut 15 exhaust pipe 10.

The decrease in the excitability of body parts is affected by an increase in the stiffness of the partitions 7, 8 and their fastening to the housing 1 by electric rivets.

In order to reduce the excitability of the end walls 5, 6 of the housing 1 and the structural noise emitted by them into the environment, the end walls 5, 6 of the housing 1 (Fig. 7) are made with U-shaped dies 24, increasing rigidity.

Reducing the noise levels of medium and high frequencies is achieved due to the sound-absorbing chamber 17, equipped with a protective sealed casing 19, with heat-resistant sound-absorbing packing 18 made of porous material placed in it and perforated openings of the exhaust pipe 14 through which exhaust gases are in contact with the packing. To increase the efficiency of using heat-resistant sound-absorbing packing 18 in reducing the aerodynamic component of the noise levels of medium and high frequencies and to eliminate the phenomenon of “axial effect” on the exhaust pipe 14, a perforated section 20 is made in front of the sound-absorbing chamber facing the wall of the housing 1.

Such a location of the perforations on the exhaust pipe 14 will allow additionally turbulize the flow of exhaust gases in the exhaust pipe, ensuring that the entire volume of exhaust gases comes into contact with the perforated section 16 of the exhaust pipe 14 located within the sound-absorbing chamber.

The inventive muffler has the property of a broadband muffler and can improve the efficiency of damping exhaust gas noise and structural noise generated by the body parts of the muffler while reducing power loss, and improve the economic and toxic characteristics of the engine.

Claims (13)

1. The silencer of the exhaust exhaust of an internal combustion engine, comprising a cylindrical body of an elliptical cross section with three chambers formed by the end walls of the body and transverse partitions, one of which is made of perforated, inlet and outlet pipes, coaxially connected inlet and outlet pipes with perforated sections, a sound-absorbing chamber with a sound-absorbing heat-resistant packing of a porous material located on the perforated section of the exhaust pipe, characterized in that the inlet and outlet pipes are provided with additional perforated sections, wherein the additional perforated section on the exhaust pipe is made behind the first partition and facing in the opposite direction from the inlet pipe, and the additional perforated section on the inlet pipe is biased towards the rear partition and made in the form of a narrow pipe cross section sector facing the exhaust pipe, the front partition is provided with perforated sections located symmetrically with respect to the major axis of the ellipse echeniya body displaced by it to the wall of the minor axis of the muffler body, a perforated portion of the back walls arranged around the inlet tube, the sound absorbing chamber is provided with a sealed protective casing disposed therein a sound-absorbing heat-resistant packing. 2. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the total passage area of the openings of the perforated section of the inlet pipe in the second chamber exceeds the total passage area of the holes of the perforated section of the first and open cut of the inlet pipe of the third chamber. 3. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the ratio of volumes V ₁ : V ₂ : V _{3 of the} first chamber to the second and third chambers is expressed as 1: 3: 2. 4. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the additional perforated sections on the inlet and outlet pipes are placed in the second chamber. 5. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the narrow sector of the additional perforated section on the inlet pipe is placed symmetrically with respect to the major axis of the ellipse section of the housing. 6. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the narrow sector of the additional perforated section on the inlet pipe faces the protective sealed enclosure of the sound-absorbing chamber. 7. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the front partition is provided with at least two perforated sections. 8. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1 or 7, characterized in that the perforated sections of the front partition are made with an increase in the number of openings to the wall of the silencer body. 9. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the perforated portion of the rear wall is made with an increase in the number of openings to the exhaust pipe. 10. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the end walls of the housing are made with U-shaped punchings, covering partially inlet and outlet nozzles with a gap. 11. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the sound-absorbing chamber is partially located in the second and third chambers, while crossing the rear wall. 12. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1, characterized in that the exhaust pipe is made elongated with a perforated portion over most of its length. 13. The silencer of the exhaust exhaust of an internal combustion engine according to claim 1 or 12, characterized in that the sound-absorbing chamber is located behind the silencer body on a perforated section of the exhaust pipe.

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