SU1362856A2 - Noise muffler - Google Patents

Abstract

The invention relates to the field of engine-building and makes it possible to increase the efficiency of a noise silencer. The silencer comprises a tubular body 1 and inlet and exhaust pipes 3 and 4 along it with peripheral overflow openings, which form an expansion chamber with it. The latter is made in the form of pipe envelopes of curvilinear confluent channels 8. At the entrance of these channels there are 6 bypass holes 6 of the pipe 3, and pipes 4 at the exit. The pipes themselves are made as continuation of one another and are separated by a solid partition. Pipe 4 is soundproofed from the housing and from pipe 3 and is provided with sound insulation from the outer surface of the Hi-CTH within the expansion chamber. A specific feature of the flow section of a silencer is the theoretically complete internal reflection of sound in the volume of the expansion chamber. This is due to its implementation in the form of curvilinear confused channels 8. The camera is a kind of acoustic trap. 2 hp f-ly, b silt. 3 1 9 V from 05 o 00 ate O5 figure 1 -Y

Description

The invention relates to mechanical engineering, in particular to engine-building, namely to the mufflers of the noise of internal combustion engines.

The purpose of the invention is to increase the effectiveness of the noise suppressor.

FIG. 1 shows a silencer, a longitudinal vertical section; in fig. 2 is a section A-A in FIG. one; in fig. 3 is a section BB in FIG. one; in fig. 4 shows a silencing system; in fig. 5 shows the node I in FIG. 1 (on an enlarged scale) in FIG. 6 — node II in FIG. 1 (on an enlarged scale).

The silencer contains a tubular body 1 with end walls 2 and inlet 3 and outlet 4 pipes placed along it with peripheral overflow openings: outlet 5 of the inlet pipe 3 and inlet 6 of the exhaust pipe 4. The outer surfaces of both tubes 3 and 4 form together with the inner surfaces body 1 expansion chamber 7, made in the form of enveloping the inlet 3 and outlet 4 pipe curved confused channels 8, at the entrance of which are located the outlet bypass holes 5 of the inlet pipe 3, and at the exit - the entrance bypass There are 6 holes in the outlet pipe 4, and these pipes themselves are made deaf. The inlet 3 and outlet 4 pipes can be made as a continuation of one another (coaxially, or, for example, from one tubular billet) and separated by a solid partition 9, serving as a general stub of the end cap of both pipes 3 and 4.

The exhaust pipe 4 (Fig. 5) is soundproofed from the housing 1 by means of separating elements installed on its both sides - bushings or rings 10 made of heat resistant sound insulating material based on asbestos (for example, mineral, glass) fibers. The sleeves 10 are enclosed in sleeves 11 with the provision of a certain tension to achieve gas tightness of the joint in the absence of direct contact between the mating metal parts.

When the inlet 3 and outlet 4 pipes are made in one piece from one tubular billet, divided into inlet and outlet parts by a metal partition, the separating element 10 on the inlet side of the housing 1 (not shown) directly contacts the inlet pipe 3, at the same time ensuring sound insulation from the housing 1 and also the inner end of the exhaust pipe 4. In this case, an elastic connection between the intake pipe 3 and the engine exhaust pipe may be required to limit the direct sound transmission from it to ypusknoy pipe 4.

The most appropriate option is (Fig. 1, 5, 6), in which the exhaust

the pipe 4 is also soundproofed from the inlet pipe 3 by means of a plug shaped partition 9, made of a material similar to the material of the sleeve 10

(if necessary - with a bearing metal reinforcement). In this case, the need for a separating sleeve 10 on the inlet side of the housing 1 is eliminated. In this case, the exhaust pipe 4 remains soundproofed from the housing 1, since it is soundproofed from the intake pipe 3 rigidly connected to it, for example by welding. It also eliminates the need for elasticity of connecting the inlet pipe 3 to the engine exhaust pipe.

5 An increase in the efficiency of noise suppression is also achieved by the fact that within the expansion chamber 7 the exhaust pipe 4 for the most part around the circumference (excluding the insignificant zone near the bypass openings 6) is provided with sound insulation of the outer surface. This sound insulation is made in the form of a sound insulation layer 12 made of traditional material covered with a thin-layer casing 13 made of corrosion-resistant material with

 the sound reflecting ability of the outer surface at the level of the sound reflecting ability of the other reflecting surfaces of the expansion chamber 7.

The outer surface of the housing 1 (as well as, if necessary, the end walls 2)

0 is provided with a conventional sound insulation in the form of a sound insulating layer 14 and a thin protective casing 15, which limit the sound emission of the housing to the surrounding space.

The muffler works as follows

5 way.

The basic principle of functioning of the silencers is the absorption and dissipation of the energy of sound vibrations during repeated reflection of sound waves, which is affected by elastic microstrain.

0 and heating materials silencer. A specific feature of the flow part of the silencer is the theoretically complete internal reflection of sound in the volume of the expansion chamber 7, due to its performance in

5 in the form of curvilinear confused channels 8. These channels create a selective effect: they freely pass a gas stream through themselves, initially carrying sound energy, and do not transmit sound vibrations to the output. This property transforms the expansion chamber 7 into a kind of sound trap.

The engine exhaust enters the muffler through the intake pipe 3 and through its exhaust ports 5 enters the expansion chamber 7. Here, the flow of gases, times5, branches into two separate streams, which, passing along curved xnfusor channels 8, go around in opposite directions x inlet 3 and release

After turning about 180 °, the 4 pipes are reunited at the outlet of the confusing channels 8, after which the combined gas flow through the inlets 6 of the exhaust pipe 4 enters and leaves it.

The graphic image in the projection of the transverse plane of the paths of propagation of sound waves emitted into the expansion chamber 7 in any directions possible within an angle of 180 ° (Fig. 4) shows that the configuration of camera 7 in the form of curvilinear channels 8 provides theoretically complete internal reflection of sound within its scope.

The typical course of the reflecting vectors of sound radiation is exaggeratedly shown by arrows {FIG. 4), whence it is seen that the elementary sound impulse undergoes multiple reflections from the walls of the expansion chamber 7, while repeatedly circulating between the two confused channels 8, but not reaching the exit from them, where the inlets 6 of the exhaust pipe are located 4. As a result, the sound vibrations attenuate with decrement due to the acoustic parameters of the system, not reaching the output of the expansion chamber 7.

The fundamental picture does not change when considering the real elementary pulse of sound radiation, which is its angle, any angle with the transverse plane.

0

j

since the longitudinal planes containing any reflectors 1 vectors (Fig. 4 and bounded by curvilinear walls of confused channels 8) do not intersect the inlets 6 of the exhaust pipe 4. At the exit of confusing channels 8 i, a gas stream not containing the main part of the primary flows into the exhaust pipe 4 sound energy. The level of residual sound energy of the flow at the outlet of the dampers, which determines the acoustic efficiency of the latter, is due to the inevitable practical deviations of sound propagation paths rasschiritelnoy-oscillations inside the chamber 7 from the theoretical geometric parameters due to imperfect reflection surfaces.

Claims (3)

1. Noise muffler autom. St. No. 1278471, characterized in that, in order to increase efficiency, the exhaust pipe is soundproofed from the body. 2. A silencer according to claim 1, characterized in that the exhaust pipe is soundproofed from the intake pipe. 3. Silencer on PP. 1 and 2, characterized in that the outlet pipe within the expansion chamber is provided with sound insulation of the outer surface. phi.2 phyaz iZ 12 FIG. five FIG. AT 12 Compiled by V. Slavnikov Editor I. CasardTechred I. VeresKorrektor S. Cherni Order 5959/23 Circulation 482 Subscription VNIIPI USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4