RU56960U1 - MULTI-CAMERA NOISE MUFFLER OF INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

The utility model relates to mechanical engineering, in particular engine manufacturing, namely, to multi-chamber silencers of exhaust noise of internal combustion engines.

The muffler comprises a cylindrical body with end walls, in which an inlet, intermediate and exhaust chambers are divided by partitions, as well as connecting cavities of these chambers of the inlet, outlet and intermediate pipes, at least in a section of the exhaust pipe of which a concentric resonator formed by a perforated section of the exhaust pipe is placed pipe and a cylindrical casing covering the perforated section of the exhaust pipe.

A distinctive feature of the silencer is that: the area of the perforations of the wall of the perforated section of the exhaust pipe inside the concentric resonator chamber is 0.6 of the area of the passage cross section of the exhaust pipe, the perforated section of the intermediate pipe is placed on the output of the concentric resonator chamber in such a way that

and the length of the non-perforated inlet of the exhaust pipe located outside the concentric resonator chamber is

Where:

L _{dead end} - the length of the non-perforated (dead end) inlet of the exhaust pipe inside the concentric resonator chamber to the first row of perforation holes;

L _input - the length of the inlet of the exhaust pipe outside the concentric resonator chamber;

L _reson - the length of the part of the exhaust pipe inside the concentric resonator chamber;

ε is the degree of perforation of the perforated part of the exhaust pipe;

d _pat - the diameter of the passage cross section of the exhaust pipe;

ε = F _{hole perforated} / F _patr.perf.

F _perforated - the total area of the perforation holes 23 of the perforated section of the exhaust pipe 10;

F _pat.perf. - the area of the outer wall surface of the perforated section of the exhaust pipe 10, bounded by the extreme edges of the holes of the first and last row of perforation.

The utility model provides high muffler performance (high silencing) mainly in the speed range of the maximum torque on the crankshaft of an internal combustion engine

1 n.p. f-ly, 5 ill.

Description

The utility model relates to mechanical engineering, in particular engine manufacturing, namely, to multi-chamber silencers of exhaust noise of internal combustion engines (hereinafter ICE).

Known exhaust silencers for internal combustion engines, the designs of which are described in RF patents Nos. 641140, 1245726, 1043329, 1019082, 1010306. These exhaust silencers for internal combustion engines include a cylindrical body with end walls, inlet and outlet chambers, inlet and outlet pipes, cuts which are respectively placed inside the cavities of the inlet and outlet chambers. Such silencers are relatively simple to manufacture, but not sufficiently effective in noise suppression to meet modern requirements of more stringent standards for the external and internal noise of vehicles.

Known exhaust silencer for internal combustion engines with higher efficiency of damping exhaust noise, copyright USSR No. 1420193, MKI 7 F 01 N 1/00, BI No. 32/88, (see also Volgin S.N. and others. Color illustrated album. Automobiles VAZ-2110, VAZ-2111, VAZ-2112 and their modifications. Moscow, “Third Rome”), adopted as a prototype, which is currently used on a number of automobile models of OJSC “AVTOVAZ” and JV “GM-AVTOVAZ”. The exhaust silencer for an internal combustion engine contains a cylindrical body with end walls, three chambers, an inlet, outlet and intermediate, separated by partitions, coaxial inlet and outlet pipes, sections of which are respectively placed inside the inlet and outlet chambers and two

intermediate pipes located axially on both sides of the housing axis, through which exhaust gas from the inlet chamber passes through open straight and side sections of the pipes, through the intermediate, into the exhaust chamber and a resonator mounted on the exhaust pipe. To attenuate the transmission of noise from the intermediate pipe to the exhaust chamber, an end plug is installed on the exhaust straight cut of this pipe, which prevents the transmission of sound along with a direct gas flow, and the gas and sound exit through perforations in the side surface of the pipe. The partition in the intermediate chamber (rear along the muffler) contains large openings and does not act as a separating element of the chamber, and in fact is a technological fastener for fixing the given spatial positions of the pipes and the resonator casing. The well-known muffler design allows it to be used at present, in particular, in passenger cars, since it has quite high sound-damping efficiency, both at medium frequencies (due to the use of three expansion chambers) and at high frequencies - including for due to the presence of a concentric resonator mounted on the exhaust pipe, which allows you to meet the requirements of existing national and international standards that limit the external and internal noise of vehicles. The disadvantage of this design of the muffler is the reduction in the efficiency of noise attenuation at the resonant frequencies of the intermediate pipe connecting the muffler to the intermediate and inlet chambers, which causes the transmission and emission of intense sound from these mufflers into the environment and does not satisfy the more stringent prospective requirements of current national and international standards, limiting the external and internal noise of vehicles.

The technical problem solved by the utility model is to increase the efficiency of the muffler, in particular, to provide high noise damping mainly in the speed range of the maximum torque on the crankshaft of the internal combustion engine.

The solution to the technical problem lies in the fact that the device of a multi-chamber exhaust silencer for engine exhaust is proposed, comprising a cylindrical body with end walls, in which an inlet,

the intermediate and exhaust chambers, separated by partitions, as well as connecting the cavities of these chambers of the inlet, outlet and intermediate nozzles, in the section of the outlet pipe of which there is a concentric resonator chamber formed by the walls of the outlet pipe and a cylindrical casing covering the perforated section of the outlet pipe, and characterized in that :

a) the area of the perforations of the wall of the perforated section of the outlet pipe covered by the cylindrical casing is 0.60 of the area of the passage cross section of the outlet pipe,

b) the perforated section of the exhaust pipe is placed on the output part of the resonator chamber in such a way that

Where:

ε = F _{drilled hole} / F _{drilled hole} ,

F _perforated - the total area of the perforation holes 23 of the perforated section of the exhaust pipe 10,

F _pat.perf. - the area of the outer wall surface of the perforated section of the exhaust pipe 10, bounded by the extreme edges of the holes of the first and last row of perforation,

c) the length of the non-perforated inlet part of the outlet pipe, (L _inlet ) located outside the resonator chamber (up to the end wall 28 of the cylindrical casing of the concentric resonator chamber 22), is equal to

Where:

L _{dead end} - the length of the non-perforated inlet of the exhaust pipe 10 located inside the resonator chamber 22 from the end wall 28 of the cylindrical casing 24 of the concentric resonator chamber to the first row of perforation holes 23;

L _input - the length of the inlet part of the exhaust pipe 10 located outside the end wall 28 of the cylindrical casing 24 of the concentric resonator chamber;

L _reson - the length of the part of the exhaust pipe 10 inside the concentric resonator chamber, limited by the end walls 28 and 29;

ε is the degree of perforation of the perforated section of the exhaust pipe 10;

d _pat - the diameter of the passage cross-section of the exhaust pipe 10;

In the industrial manufacture of the silencer design, deviation intervals from the declared values are permissible, which can be ± 1% of the nominal value and are due to manufacturing tolerances indicated in the technical documentation (working drawings).

Due to this feature of the silencer device, as shown by studies of prototypes, its high efficiency (high noise damping) was achieved mainly in the speed range of the maximum torque on the crankshaft of the internal combustion engine.

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

The proposed technical solution is industrially applicable, because can be manufactured industrially, efficiently, feasibly and reproducibly, therefore, meets the patentability condition "industrial applicability". At the same time, a useful model can be implemented in industrial production using standard equipment, modern materials and technology.

Other features and advantages of the claimed utility model will become apparent from the following detailed description, given solely in the form of a non-limiting example and with reference to the accompanying drawings, illustrating a preferred embodiment in which;

- figure 1, 2 presents a diagram of the design of the inventive muffler,

- figure 3 schematically shows the path of the oscillatory and stationary flows of exhaust exhaust gases of the internal combustion engine through the exhaust pipe 10 when excited in it resonant gas oscillations.

Symbols of physical parameters characterizing the operation of the muffler are given below:

light arrows ⇐ - stationary exhaust gas flow (m ³ / s);

dark arrows ### U231 - oscillatory volumetric flow rate of exhaust gases (m ³ / s);

P ₇ - the vibrational pressure of the exhaust gases in the cavity of the exhaust chamber 7 at a free open cut 15 of the exhaust pipe 10;

q ₂₃ - oscillatory volumetric flow rate of exhaust gases from the cavity of the exhaust pipe 10 through the perforation holes 23 into the external closed volume of the resonator chamber 22;

q ₁₅ is the oscillatory volumetric flow rate of exhaust gases in the cross section of the cut 15 of the pipe 10 from the exhaust chamber 7 to the exhaust pipe 10;

q ₃₁ - oscillatory volumetric flow rate of exhaust gases in the cross section of a slice 31 of the pipe 10 from the exhaust pipe 10.

- figure 4 presents the overall noise levels of the exhaust system of the exhaust system, measured at 0.25 m from the exhaust pipe of the car;

- figure 5 presents 1/3 octane spectra of noise levels of the exhaust system of the exhaust system, measured at 0.25 m from the exhaust pipe of the car, at the speed of the maximum engine torque.

The design of a multi-chamber exhaust silencer for internal combustion engines shown in FIG. 1 and FIG. 2 comprises a cylindrical housing 1 with end walls 2 and 3, in which three chambers are formed by two transverse walls 4 and 5: inlet chamber 6, exhaust chamber 7 and intermediate chamber 8, coaxially located inlet pipe 9 and outlet pipe 10 and intermediate pipes 11 and 12 axially placed on both sides of the housing axis. The inlet pipe 9 communicates with the inlet chamber 6 through the perforation holes 13, on the pipe 9. The end part of the inlet the quick nozzle 9 located in the cavity of the exhaust chamber 7 is closed by a blind end cap 14. The exhaust nozzle 10 communicates with the exhaust chamber 7 through an open straight cut 15. The intermediate nozzle 11 communicates with the inlet chamber 6 through a straight cut 16, and through the intermediate chamber 8 a straight cut 18 and with a volume 26 between the pipe 11 and the casing 27 through the perforation holes 17. The intermediate pipe 12 communicates with the intermediate chamber 8 through an open free cut 19, and with the outlet chamber 7 through the perforation holes 20 on the pipe 12.

From the side of the inlet chamber 6, in the slice of the intermediate pipe 12, a blind end cap 21 is installed.

On the section of the exhaust pipe 10 in the cavity of the intermediate chamber 8, a concentric resonator chamber 22 is formed, formed by perforation with holes 23 of the section of the exhaust pipe 10, closed (covered) by a continuous cylindrical casing 24.

The muffler works in the usual way.

The exhaust gases, together with the noise energy of the gas stream, during the internal combustion engine workflow, are led to the muffler via the exhaust pipe, distributed through the inlet pipe 9 of the muffler and through the perforations 13 enter the cavity of the intake chamber 6 of the muffler. In the areas of the perforation holes 13 in the chamber 6 cavity, due to the sharp expansion of the acoustic waveguide and the resulting abrupt change in the wave resistance, determined by the ratio of the total area of the passage sections of the perforation holes 13 of the inlet pipe 9 to the passage area of the chamber 6, the sound waves are partially reflected back to the radiation source ( exhaust valve - not shown in the drawings). This process is also facilitated by a blind end cap 14, which blocks the direct transmission of sound that is not attenuated in the muffler from the inlet pipe 9 to the exhaust chamber 7 and then to the exhaust pipe 10. An unreflected part of the sound wave energy is transmitted and transported towards the direct cut 16 of the intermediate pipe 11. As a result an abrupt change in the wave impedance, determined by the ratio of the passage sections of the chamber 6 and the intermediate pipe 11, the sound waves are partially reflected in the direction of the source exercises (to the exhaust valve) and are partially transmitted from the cavity of the chamber 6 through a straight section 18 of the intermediate pipe 11 to the intermediate chamber 8, where due to the sharp expansion of the acoustic waveguide on the free section 18 in the chamber cavity they lose some of the sound energy and, then, are transferred to the free open cut 19 of the intermediate pipe 12 and, due to the sharp narrowing of the acoustic waveguide, are partially reflected, including in addition from the end cap 21 of the pipe 12, back towards the radiation source (to the exhaust valve well), and partially transmitted from the cavity of the chamber 8 through

the perforation holes 20 of the intermediate pipe 12, into the cavity of the exhaust chamber 7, where due to the process of sharp expansion along the propagation path along the acoustic waveguide in the chamber cavity, part of the sound energy is lost and, further, partially transferred to the free cut 15 of the exhaust pipe 10 and, due to the sharp narrowing of the passage sections of the pipe 10, as a transmitting element of the acoustic waveguide, are partially reflected towards the radiation source (to the exhaust valve) and partially pass through the exhaust pipe 10, fall into the cavity l the resonator chamber 22 formed by the perforated holes 23 of the section of the pipe 10, covered by a continuous cylindrical casing 24, lose energy of a given frequency range in the resonator chamber 22 during frictional resonant (with large amplitudes) oscillations of the gas and then through the exhaust pipe 10 and the exhaust pipe (not shown) are released into the atmosphere.

However, the operational efficiency of the known design of a silencer (prototype) is significantly deteriorated with the occurrence of frequency bands of transmission of undamped sound energy when longitudinal resonant gas vibrations are excited in the resonator chamber 22 in its own vibrational mode with the sound wave frequency equal to twice the length of the resonator chamber 22 (L _reson ).

To attenuate these spurious resonant vibrations gas on its own longitudinal mode resonator chamber 22, part of the exhaust pipe 10, located inside the cavity resonator chamber 22 is performed imperforate over the length L _standstill so that formed in the deadlock portion of the resonator chamber 22 annular quarter wave resonator 30 suppressing spurious longitudinal resonant gas vibrations arising in the resonator chamber 22 on this eigenmode with a wavelength equal to twice the length of the resonator chamber 22 (L _res )

In addition, in the described design of the muffler there is a resonant transmission of sound at frequencies of the first longitudinal resonance of the input non-perforated section of the exhaust pipe 10 of length L _input + L _{dead end} . Due to the optimal choice of the length L of the _{dead end} section, this section of the nozzle is tuned to the frequency of effective suppression of natural resonance vibrations by the formed dead end ring resonator 30 integrated in the resonator chamber 22 and undesirable resonant amplification of vibrations in it

also becomes low-risk.

Thus, the dead-end ring resonator 30 integrated into the cavity of the resonator chamber 22 allows additionally improving the noise damping characteristics of the multi-chamber silencer.

For the most efficient dissipation of the resonant vibrational energy of the exhaust gases, the location of the openings 23 of the perforations of the exhaust pipe 10, their area and the corresponding lengths of the elements of the exhaust pipe 10 (L _inlet , L _cut and L _{dead end} ) should be consistent both with each other and with the operating mode of the internal combustion engine.

Computer simulation of the acoustic and gas-dynamic processes taking place in the device, according to the claimed design of the silencer, showed that it is rational from the point of view of ensuring high efficiency of its (silencer) operation (ensuring high noise damping mainly in the speed range of the maximum torque on the engine crankshaft), is a mutually agreed choice of these design parameters from the following considerations:

A) the area of the holes of the perforations 23 of the wall of the perforated section of the outlet pipe 10 inside the concentric resonator chamber 22 is 0.6 of the area of the passage cross section of the outlet pipe 10,

B) the perforated section of the exhaust pipe 10 is placed on the output part of the concentric resonator chamber 22 in such a way that

Where:

ε = F _{drilled hole} / F _{drilled hole} ,

F _perforated - the total area of the perforation holes 23 of the perforated section of the exhaust pipe 10,

F _pat.perf. - the area of the outer wall surface of the perforated section of the exhaust pipe 10, bounded by the extreme edges of the holes of the first and last row of perforation,

B) the length of the non-perforated inlet of the exhaust pipe 10 located outside the concentric resonator chamber 22 is equal to

Where:

L _{dead end} - the length of the non-perforated (dead end) inlet of the exhaust pipe 10 located inside the cavity of the concentric resonator chamber 22 to the first row of perforation holes 23;

L _input - the length of the inlet of the exhaust pipe 10 located outside the concentric resonator chamber 22;

L _reson - the length of the part of the exhaust pipe 10 inside the concentric resonator chamber 22 between its end walls 28 and 29;

ε is the degree of perforation of the perforated section of the exhaust pipe 10;

d _pat - the diameter of the passage cross-section of the exhaust pipe 10;

ε = F _{drilled hole} / F _{drilled hole} ,

F _perforated - the total area of the perforation holes 23 of the perforated section of the exhaust pipe 10,

F _pat.perf. - the area of the outer wall surface of the perforated section of the exhaust pipe 10, bounded by the extreme edges of the holes of the first and last row of perforation.

Thus, the design of a high-performance sound-damping multi-chamber silencer for the exhaust of an internal combustion engine is implemented, due to the exclusion of resonant amplifications of the sound energy of the transported exhaust stream in its end silencing structural element, the exhaust pipe, which allows to reduce the acoustic pollution of vehicles equipped with piston internal combustion engines.

Claims (1)

1. A multi-chamber exhaust silencer for internal combustion engines, comprising a cylindrical body with end walls, in which an inlet, intermediate and exhaust chambers are separated by partitions, as well as connecting cavities of these chambers of the inlet, outlet and intermediate pipes, in the area of the exhaust pipe of which a concentric resonator chamber is located formed by a perforated section of the exhaust pipe and a cylindrical casing covering the perforated section of the exhaust pipe, characterized in that the area The perforation wall of the wall of the perforated section of the exhaust pipe inside the concentric resonator chamber is 0.6 of the area of the passage cross section of the exhaust pipe, the perforated section of the intermediate pipe is placed on the output part of the concentric resonator chamber so that

and the length of the non-perforated inlet of the exhaust pipe located outside the concentric resonator chamber is

where L is a _{dead end} - the length of the non-perforated inlet of the exhaust pipe inside the concentric resonator chamber to the first row of perforation holes; L _input - the length of the inlet of the exhaust pipe outside the concentric resonator chamber; L _reson - the length of the part of the exhaust pipe inside the concentric resonator chamber; ε is the degree of perforation of the perforated part of the exhaust pipe; d _pat - the diameter of the passage cross section of the exhaust pipe; ε = F _{hole perforated} / F _patr.perf., where F _otv.perf. - the total area of the perforation holes 23 of the perforated section of the exhaust pipe 10; F _pat.perf. - the area of the outer wall surface of the perforated section of the exhaust pipe 10, bounded by the extreme edges of the holes of the first and last row of perforation.