RU2224897C2 - Muffler for internal combustion engine - Google Patents

Abstract

FIELD: mechanical engineering; internal combustion engines. SUBSTANCE: proposed muffler contains hollow mainly cylindrical, housing, three perforated partitions secured in housing, and intake and outlet pipes with perforated holes over periphery coaxial with housing. Intake pipe is provided with end face stopper at outlet and outlet pipe, end face stopper at inlet. Two partitions are made cross and flat, and one, coaxial with housing, is made conical and arranged between cross partitions, being rigidly secured by its bases to planes of partitions with smaller base towards intake pipe. Outlet of intake pipe and inlet of outlet pipe are located in chamber formed by three partitions, and perforation holes of intake and outlet pipes are located at both sides of cross partitions holding the pipes. EFFECT: reduced noise level. 1 dwg

Description

 The invention relates to internal combustion engines, in particular to silencers with throttling of the exhaust gas stream.

 Known silencer with throttling of the exhaust gas flow of internal combustion engines, described, for example, in US patent 4192403 [1], owned by the Japanese company Honda Gicken. The exhaust muffler for internal combustion engines contains a predominantly hollow hollow body, a coaxial inlet pipe with an end cap at the outlet and perforations at the periphery and an exhaust pipe that is coaxially mounted in the cylindrical cavity of the body. A perforated transverse partition is installed in the cavity of the silencer body, dividing the silencer cavity into two communicating chambers, the inlet pipe openings being made on both sides of the transverse partition holding it. The exhaust gas flow in this muffler is throttled, divided into two parts in the area of the first resonant chamber, then through the transverse baffle it enters the second chamber, where it meets at right angles the exhaust gas flowing from the perforation openings of the inlet pipe located on the other side of the transverse baffle . This silencer design does not provide reliable noise suppression, as it has only one resonance chamber that does not provide noise suppression in the entire spectrum of sound frequencies, and one chamber that absorbs the energy of exhaust gases due to the mutual influence of separated wave systems.

 More effective is an exhaust silencer installed on a Moskvich M-408 automobile, which was produced in Russia [2]. This silencer comprises a predominantly hollow hollow body, three baffles fixed in the body cavity, an inlet pipe coaxial to the body with an end cap at the outlet and perforations at the periphery, and an exhaust pipe with an end cap at the inlet and perforations at the periphery. Moreover, all partitions are flat and divide the silencer cavity into four successively connected chambers along the gas flow, for which the first and third partitions have perforations, and the inlet pipe in the area of the second chamber has a blind partition. In addition, the exhaust pipe located in the fourth chamber is fixed at an acute angle to the geometric axis of the housing. Portions of exhaust gases with a frequency specified by the piston mechanism of the internal combustion engine will fall from the side openings of the inlet pipe into the first resonance, and then, with some delay, into the second mixing chamber. The exhaust gas flow from the first chamber at a right angle meets the exhaust gas flowing from the perforation openings of the exhaust pipe, which are located on the other side of the first transverse partition. In this case, as a result of the interaction of the two wave systems, the resulting gas stream loses its energy and with a significantly smoothed frequency component through the side openings located behind the blank partition of the inlet pipe, falls into its continuation. Before entering the exhaust pipe located in the fourth expansion chamber, the attenuated gas stream is further throttled in the third resonance chamber.

 However, such a silencer does not provide effective silencing of exhaust gases due to the insufficient length of the perforated part of the inlet pipe in the area of the first and third resonance chambers. On the other hand, there are only two resonant chambers in the design of this muffler, which is why sound suppression is limited by a narrow frequency range around the resonant frequency.

 The objective of the proposed technical solution is to create a silencer in which the exhaust gas flow is throttled many times and, changing its direction, gets into four resonant-expansion chambers. This will reduce the noise level to 77 dBA without significantly affecting the power of the internal combustion engine.

 The problem is solved in that in the known exhaust gas silencer for internal combustion engines (comprising a predominantly hollow cylindrical body, three partitions fixed in the body cavity, an inlet pipe coaxial to the body with an end plug at the outlet and perforations at the periphery and an exhaust pipe with an end plug at the inlet and perforation holes on the periphery) all partitions have perforation holes, two partitions are transverse flat, and one conical to the conical body is located between the transverse and rigidly fixed with its bases to their planes smaller base towards the inlet pipe, the exhaust pipe is placed coaxially with the housing, while the outlet of the inlet pipe with an end cap and the entrance of the outlet pipe with an end cap are placed in a chamber formed by three partitions, and perforations the inlet and outlet pipes are made on both sides of the transverse partitions holding them.

 The three walls of this muffler form four chambers in the course of the gas flow - the inlet resonance, the external and internal concentric resonance chambers, and the exhaust resonance. The muffler thus has four types of resonant cavities and has a resonant frequency at four points.

 The invention is illustrated in the drawing, in which a longitudinal section shows a silencer of exhaust gases of internal combustion engines that implements the present invention.

 The silencer comprises a hollow cylindrical body 1 with a geometric axis X-X, an inlet pipe 2, coaxial to the cylindrical body 1, a first transverse (perpendicular to the X-X axis) flat partition 3, a conical partition coaxial to the cylindrical body 1, a second transverse flat partition 5 and an exhaust the pipe 6, coaxial to the cylindrical body 1. Of course, the cylindrical body 1 can be both circular and elliptical, and the flat bases of the cylinder can (to eliminate stagnant zones) be replaced, for example, with spherical caps. Three partitions 3, 4 and 5 form in the cavity of the housing 1 four resonance chambers - inlet A, two concentric chambers - external B and inner C and exhaust chamber D. The conical partition 4 is located between the flat transverse partitions 3 and 5 and is rigidly attached to them by bases (smaller base towards inlet pipe 2). The partitions 3, 4 and 5 are provided with perforations 7, which provide a connection between chamber A and chamber B, chamber B and chambers B and D, as well as chambers C and D. The inlet pipe 2 has perforations 8 and 9 at its periphery and an end cap 10 at the exit. The exhaust pipe 6 has an end cap 11 at the inlet and perforations 12 and 13 at its periphery. In this case, the outlet of the inlet pipe 2 with the end cap 10 and the entrance of the outlet pipe 6 with the end cap 11 are placed in the internal resonance chamber B formed by three partitions 3, 4 and 5, the perforations 8 and 9 of the inlet pipe 2 are made on both sides of the transverse retaining it partitions 3, and the perforations 12 and 13 of the exhaust pipe 6 are made on both sides of the transverse partition 5 holding it.

 The muffler works as follows.

 Portions of exhaust gases with a frequency specified by the piston mechanism of the internal combustion engine enter the cavity of the cylindrical body 1 through the inlet pipe 2, which throttles and distributes the gas flow into two parts: larger and smaller. Most of the flow is formed by the perforations 8 of the pipe 2 and is directed perpendicular to the axis XX of the inlet pipe 2 to the inlet resonance chamber A, where it is damped by resonance and exits through the openings 7 in the transverse baffle 3 into the outer concentric resonance chamber B. The smaller part of the flow is due to the closed end plug 10 is formed by the openings 9 of the pipe 2 and is directed perpendicular to the axis X-X into the internal concentric resonance chamber B. The magnitude of the gas flows are proportional to the total cross sections from versts 8 and 9. In the internal concentric resonance chamber B, the flow is damped by resonance and throttled again and divided into three streams. One of them is guided through openings 7 in the conical baffle 4 to the external concentric chamber B, the second through openings 7 in the baffle 5 to the exhaust resonance chamber G, and the third gas stream, due to the presence of the end cap 11 at the inlet of the exhaust pipe 6, is guided to through the openings 12. The first gas stream, having fallen from the internal concentric resonance chamber B to the outer chamber B, meets the flow of exhaust gases from the chamber A at an angle. Moreover, as a result of the interaction of two wave systems, the resulting gas ok, it loses its energy and with a significantly smoothed frequency component through the openings 7 in the partition 5 is displaced into the chamber D. The second gas stream from the chamber B in the resonant exhaust chamber D is mixed with the gas stream from the chamber B, and the resulting gas flow through the holes 19 in the exhaust pipe 6 is discharged into the atmosphere. The third gas stream, having entered the exhaust pipe 6 directly from chamber B, is also discharged into the atmosphere, but having experienced the additional effect of the resulting gas flow from chamber G entering through the openings 19 in the exhaust pipe 6.

 Comparative tests of a silencer made in accordance with the present invention show that the level of external noise emitted by a stationary car with this silencer is 9 dBA lower than the level of external noise when using a silencer of the Moskvich automobile on the same car and amounts to 77 dBA .

LITERATURE
1. T. Nakagava (Honda Giken Kogyo). Muffler for internal combustion engines. US Patent 4,192,403, US Cl. 181/268, filed May 23, 1978, publ. March 11, 1980.

 2. S.F. Demikhovsky et al. Design and operation of Zhiguli and Moskvich cars. M., publishing house DOSAAF, 1987.

Claims (1)

An exhaust muffler for internal combustion engines, comprising a hollow, predominantly cylindrical, housing, three partitions fixed to the housing cavity, an intake pipe coaxial to the housing with an end cap at the outlet and perforation holes at the periphery and an exhaust pipe with an end cap at the inlet and perforations at the periphery, characterized in that all the partitions have perforations, two partitions are transverse flat and one coaxial conical body located between the transverse with a smaller base rigidly attached to their planes to the side of the inlet pipe, the exhaust pipe is placed coaxially with the housing, while the outlet of the inlet pipe with the end cap and the entrance of the outlet pipe with the end cap are placed in the chamber formed by three partitions, and the perforation inlet and exhaust pipes are made on both sides of the transverse partitions holding them.