SU1645574A1 - Muffler for internal combustion engine - Google Patents

Abstract

The invention relates to mechanical engineering and makes it possible to increase the efficiency of sound attenuation by optimizing the structural dimensions of the silencer elements. The flow of exhaust gases carrying sound energy flows through the inlet pipe 8 into the central tube 6, where the sound waves, reflecting from the plug 7 and rubbing some of the energy, pass through the perforation of the tube 6 into the expansion chamber formed by the housing 1 and the cup 4 configured using perforated holes at a given frequency. From the expansion chamber, weakening the sound energy, the exhaust gases enter the slit-like gaps 5 of width d I / 4 and the length of IL / 4 formed by the cup 4 and the inner surface of the housing 1. The slit-shaped gaps 5 practically weaken the sound energy across the entire width of the spectrum exhaust noise without creating a flow resistance, and the beginning of the gaps 5 is located in the natural vibration nodes, which in the case of a parallelepiped-shaped case, will be located at points defined by a quarter and a half of the length of the body 1. Of the gaps 5 exhaust gases enter the next expansion chamber, which is tuned to a given frequency, and through the perforations of the pipe 6 and the outlet 9 are removed to the outside. 2 Il. (Ls

Description

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FIELD OF THE INVENTION The invention relates to mechanical engineering, in particular, engine-building, namely, to silencers of engine exhaust noise.

The purpose of the invention is to increase the efficiency of sound attenuation.

Figure 1 shows the muffler, a longitudinal section; figure 2 - section aa in figure 1.

The silencer comprises a housing 1 with coaxially inlet 2 and exhaust 3 openings and at least one pair of central quarter-wave glasses 4 installed to form a slit-like gap 5 relative to the inner surface of the housing 1. The silencer is equipped with a central perforated tube 6 with plugs 7, an inlet 8 and outlet 9 nozzles are made integral with pipe b and are placed in inlet 2 and outlet 3, holes 4 are mounted with inlet ends facing one another with the formation of axial backlash 10 between them, muffled ki 7 are located in the plane of the bottoms of the glasses 4 and in the gap 10 between the latter, the housing 1 and the glasses 4 in cross section are made in the form of elongated octahedrons, the width of the slit-shaped gaps 5 and the length of the glasses 4 are made in accordance with the formulas; A.

four;

 -

four

where d is the width of the gap 5;

I-wavelength of the highest frequency of the muffled frequency range;

I - the length of the glass 4;

L - body length 1.

The muffler works as follows.

The exhaust gas flow carrying sound energy flows through the inlet pipe 8 into the central tube 6, where the sound waves, reflected from the plug 7 and rubbing energy, pass through the perforation of the tube 6 into the stretching chamber formed by the body 1 and the cup 4, tuned using perforated holes at a given frequency. From the expansion chamber, weakening the sound energy, the exhaust gases fall into the slit

gaps 5 of width d - and a length of I, -,

formed by the cup 4 and the inner surface of the housing 1. The acoustic resistance of the gap of the gap 5 is determined by its width d and length I. The slots are most effective for reducing sound waves whose lengths I are large compared to the width d of the slot, i.e. execution width

slits d y where the wavelength is the highest

frequencies that need to be muffled can attenuate sound energy across the entire exhaust spectrum. Run the resulting ratio almost

for high frequency, for example, f 8000 Hz, without degrading the hydraulic characteristics of the muffler, it is possible to choose the octahedral shape of body 1 and cup 4. Thus, the slit-like gaps 5 are practically

attenuates sound energy across the entire width of the exhaust noise spectrum without creating resistance to the flow. The length I of the slit-shaped gaps 5 is determined by the length of the cup 4, is performed in accordance with the formula

 four

where L is the length of body 1, which allows placing the beginning of the slit-like gaps 5 into the natural vibration nodes, which, as is well known, in the case of a parallelepiped form, will be located at points defined by a quarter and a half of the body 1, reduce the noise level The most intense parts of the spectrum are assisted by the resonant chambers formed by the cavity of the cups 4 and the perforation of the tube 6. The location of the plugs 7 in the plane of the bottoms of the cups 4 and in the gap 10 between the latter allows

passing the entire flow of sound energy through the slit-like gaps 5.

Claims (1)

From the slit-like gaps 5, the exhaust gases enter the next expansion chamber, which is tuned to a predetermined frequency, and through the perforations of the pipe 6 and the outlet 9 are removed to the outside. Claims An exhaust silencer for an internal combustion engine comprising a housing with coaxial inlet and outlet openings and at least one pair of central quarter-wave glasses installed to form a slit-like gap relative to the inner surface case, characterized in that, in order to increase the efficiency of sound attenuation, it is provided with a central perforated tube with plugs, the inlet and outlet connections are integral with tube and placed in the inlet and outlet holes, the glasses are installed with the inlet ends facing one another to form an axial gap between them, the plugs are placed in the plane of the bottoms of the cups and in the gap between the latter, the body and the glasses in cross section are in the form of elongated octagons, the width of the slit-like gaps and the length of the glasses are made in accordance with the formulas "four  four where d is the width of the gap; And - wavelength of the highest frequency in the muffled range of frequencies; I is the length of the glass; L - body length. FIG. 2