SU1317170A2 - Noise silencer - Google Patents

Abstract

The invention relates to the field of engineering. The purpose of the invention is to increase the efficiency of the silencer by improving manufacturability and reducing material intensity. The inlet and outlet pipes 3 and 4 are placed in a tubular body 1 with end walls 2 and are equipped with peripheral bypass holes 5 and 6 to form an expansion chamber 7 with the body 1. The pipes 3 and 4 are made in one piece and separated by a partition 9 installed in the transverse direction. Within the chamber 7 pipe 3m.b. is made with a length greater than the length of pipe 4, and the ratio of the lengths of pipes 3 and 4 may be 1.5-4. The sound pulse undergoes multiple reflections from the walls of chamber 7, repeatedly circulating between confused channels, but not reaching the exit from them. As a result, the sound signals fade out with decrement due to the acoustic parameters of the system and do not reach the exit from camera 7. 2 zp f-ly, 4il. e te (L with with j fig. 1 K)

Description

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

The aim of the invention is to increase the efficiency of the silencer by improving manufacturability and reducing material consumption.

Figure 1 presents the scheme of the muffler, a vertical section; figure 2 - section aa, figure 1; on fig.Z - secheni.e bb in fig. 1; in Fig. 4, the diagram is illustrated; and the operation of the muffler. . .

The silencer contains a tubular body 1 with end walls 2 and inlet 3 and outlet 4 pipes arranged along it, provided with peripheral overflow holes 5 and 6, made deaf and forming with the body 1 an expansion chamber 7, filled in the form of enveloping pipes 3 and 4 curvilinear confuser channels 8, at the inlet of which are located the bypass openings 5 of the inlet pipe 3, and at the outlet - the bypass openings 6 of the outgoing pipe 4.

The inlet 3 and outlet 4 pipes are made in one piece and separated by a partition 9, installed in the transverse direction and serving as a common pipe plug 3 and 4. Confusion channels 8, covering pipes 3 and 4 in opposite directions at approximately ISC, begin at the outlet openings 5 of the inlet pipe 3 and terminate at the inlet openings 6 of the exhaust pipe, and the actual gas path has an irregular screw shape.

Confusion channels 8 can be made with a total area of the output section equal to or within 0.8-1.2 area of the section of the output pipe 4, the width of the input section of confusion L of channels 8, which determines the degree of confusion on the one hand, and the other. - the degree of sudden expansion of gases in the expansion chamber 7, corresponds to the outer diameter of the inlet 3 and or exhaust pipe 4 and can be made in the range of 0.5-1.2 of the diameter of the pipes 3 and 4.

The size and number of peripheral holes 5 and 6 of pipes 3 and 4 are also determined from the condition given

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the ratio, for example, the equality of the average gas flow rates in these openings and in the full sections of these pipes. The bypass peripheral holes 5 of the inlet pipe 3 can be arranged in one or several (two, three) longitudinal rows and have a round or slit-like shape down to a single solid slit hole. The holes 6 of the pipe 4 are expediently arranged in one longitudinal row and made in the form of a longitudinal slit (s) so that their circumferential size (width) is minimal for reasons of achieving, with all other conditions being equal, the maximum effective angle of coverage of confused channels 8.

The partition 9 can be arranged in such a way that, within the expansion chamber 7, the inlet pipe 3 has a shorter length than the height of 4, and the ratio of these lengths can be from 1: 1.5 to 1: 4 depending on the specific geometrical dimensions and gas-dynamic parameters. This may be necessary in order to maintain the maximum effective coverage angle of the confused channels 8 and thereby prevent a possible undesirable decrease in the noise level when the transverse partition 9 is arranged. For example, if the partition 9 is equidistant, the width of the openings (slots) 5 and 6 must be increased to double down This will appropriately reduce the effective coverage angle of the confused channels 8 and if this is not essential at their input, then the output can negatively affect the effectiveness of sound attenuation. Increasing in this way the length of the exhaust pipe 4 due to the inlet 3, it is possible to compensate for the decrease in the effectiveness of sound attenuation, since the circumferential size of the inlet ports 6 of the exhaust pipe 4 can be reduced accordingly.

The muffler works in the following way.

The work of the silencer is based mainly on the use of the absorption and dissipation of the energy of sound waves upon the repeated reflection of sound waves, which is expended on elastic microstrain and heating.

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material muffler. 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 execution in the form of curvilinear confused channels 8. These channels create a selective effect — they freely pass through the gas stream, initially carrying sound energy, and do not allow sound vibrations to exit. This property turns the expansion chamber 7 into a kind of acoustic trap.

The exhaust gases of the internal combustion engine flow into the muffler through the intake pipe 3 and through the outlet openings 5 pass into the expansion chamber 7. Here the gas flow splits into two separate streams which, passing through curvilinear confused channels 8, bend around the B in opposite directions of the inlet 3 and the outlet pipe 4, after turning approximately 180 times, are again connected at the exit from the confluent channels 8, after which the combined gas flow through the inlets 6 of the discharge pipe 4 enters it and leaves at the atmosphere.

The propagation paths of sound waves, radiating into the expansion chamber 7 in any direction possible within an angle of 1/180 (Fig. 4), show that the configuration of camera 7 in the form of curvilinear confused channels 8 provides the theory of A complete internal reflection of sound within its volume, not including the exit zone of channels 8. A typical course of reflecting sound emission vectors is exaggeratedly shown by arrows (Figure 4), from which it can be seen that an elementary sound pulse undergoes multiple reflections from the walls of of the chamber 7, repeatedly circulating with each other by both confused channels 8, but not reaching the exit from them, where the inlet openings 6 of the exhaust pipe 4 are located. As a result, the sound vibrations are damping .4

with a decrement due to the acoustic parameters of the system, do not reach the exit from the expansion chamber 7. The principal picture does not change when considering a real elementary pulse of sound radiation that makes up any angle with the transverse plane, since the longitudinal planes containing any reflecting vectors and bounded by curvilinear walls confused channels 8, do not cross the inlet holes 6 of the exhaust pipe 4.

At the exit of the confused channels 8 and further into the exhaust pipe 4, the gas flow enters, which no longer contains the main part of the primary sound energy. The level of residual sound energy at the outlet of the silencer, which determines the efficiency of the latter, is due to the inevitable practical deviations of the propagation of sound vibrations inside the expansion chamber 7 from the theoretical ones due to non-ideal geometrical parameters of reflective surfaces, as well as sound transmission to the outgoing flow from the silencer directly through conductive the walls of its parts.

Claims (3)

1. Noise muffler autom. St. No. 1278471, distinguished by the fact that, in order to increase efficiency by improving manufacturability and reducing material consumption, the partition is located in the transverse direction. 2. Silencer pop. 1, characterized in that within the expansion chamber the exhaust pipe is made with a length longer than the intake pipe. 3 .. The muffler according to claim 2, characterized in that the ratio of the lengths of the exhaust to the intake pipes is 1.5-4. 6-6 FIG. g Fig.Z Editor Y. Sereda Compiled by V.Slavnikov Tehred L. Oliynyk Proofreader A.Obruchar Order 24-04 / 30 Circulation 481 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul, Proektna, 4 erra g A