RU56962U1 - 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 separated by partitions, as well as connecting strips of these chambers of the inlet, outlet and intermediate pipes.

A distinctive feature of the silencer is that:

the length of each of the intermediate pipes is at least half of the total length of the internal volumes of the cavities of the intake, intermediate and exhaust chambers of the muffler,

the volume of the cavity of the intermediate chamber is 0.57 of the total internal volume of the cavities of the inlet, intermediate and exhaust chambers of the muffler ("V"),

the volume of the cavities of the intake and exhaust chambers of the silencer individually is 0.18 and 0.26 ("V"), respectively

1 n.p. f-3, 3 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 F 01 N 1/00, BI No. 32/88, (see also S. Volgin and others. Color illustrated album. Cars VAZ-2110, VAZ-2111, VAZ-2112 and their modifications. Moscow, “Third Rome”), adopted as a prototype, which is currently used on a number of car 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 an intermediate, into the exhaust chamber, and a concentric resonator chamber 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 a 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 chamber 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 transport media st. The disadvantage of this design of the muffler is the incomplete use of the potential damping capacity of the muffler due to the non-optimal mutual ratio of chamber volumes in the low frequency region, especially at the frequency of the main working harmonic of the internal combustion engine (the frequency of the working process is the repetition rate of the exhaust pulses), which leads to additional transmission and sound at these frequencies from the silencer into the environment and does not satisfy the more stringent prospective requirement of national and international projects standards limiting the external and internal noise of vehicles.

The technical problem solved by the utility model is to increase the muffler's efficiency, 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 internal combustion engines is proposed.

connecting the cavity of these chambers inlet, outlet and intermediate nozzles, and characterized in that:

the length of each of the intermediate nozzles is at least half of the total length of the internal volumes of the intake, intermediate and exhaust chambers of the muffler (minus the thickness of the internal partitions separating the cavities of the inlet, intermediate and exhaust chambers);

the volume of the intermediate chamber is (0.57) of the total internal volume of the intake, intermediate and exhaust chambers of the silencer (V) (the volumes of the chambers are determined taking into account the subtraction of the volumes occupied by the internal nodes, i.e., pipes covered by the outer shells of the resonators) ;

the volumes of the intake and exhaust chambers individually are 0.18 and 0.26 V, respectively.

The interval of deviations from the claimed geometric values may be +/- 1% and depends on the tolerances of the design documentation.

Due to this feature of the silencer device, a maximum decrease in the values of the lowest natural frequencies of the silencer due to gas vibrations in the intermediate nozzles as concentrated masses is achieved, and as experimental studies have shown, its high efficiency (high noise damping) is achieved mainly in the speed range of the maximum torque on the engine crankshaft .

A comparison of scientific, technical and patent documentation on the priority date in the main and related sections of the MKI shows the totality of the 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 are understood 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 on which;

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

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 plug 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 with the intermediate chamber 8 through a straight cut 18 and with a volume 26 between the pipe 11 and the casing 27 through the holes of the perforation 17. The intermediate pipe 12 communicates with the intermediate chamber 8 through an open free cut 19, and with the exhaust chamber 7 through the holes of the perforation 20 on the pipe 12. C the inlet side in the slice chamber 6 of the intermediate pipe 12 is mounted a blind end cap 21.

Figure 3 shows the results of comparative tests of the total noise levels of the exhaust system exhaust, complete with a muffler prototype and a muffler, made in conjunction with the claimed values and ratios of volumes, chambers.

Figure 4 shows the comparative spectra of sound pressure at revolutions of the maximum torque of the engine.

The muffler works in the usual way.

The exhaust gases, together with the noise energy of the pulsating gas stream, during the implementation of the internal combustion engine workflow, are led to the silencer through the exhaust pipe, distributed through the intake pipe 9 of the silencer and through the perforations 13 enter the cavity of the intake chamber 6 of the silencer. In the zones of the perforation holes 13 in the cavity of the chamber 6 due to the expansion of the acoustic waveguide and the resulting

an abrupt change in wave resistance, determined by the ratio of the total area of the passage sections of the perforations 13 of the inlet pipe 9 to the area of the passage section of the chamber 6, sound waves are partially reflected back to the radiation source (exhaust valve is 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 Anu), and are partially transferred from the cavity of the chamber 8 through openings, perforations 20 of the intermediate pipe 12, to the cavity of the exhaust chamber 7, where due to the process of sharp expansion along the propagation path along the acoustic waveguide, part of the sound energy is lost in the chamber cavity and then partially transferred to the free a cut 15 of the exhaust pipe 10 and, due to the sharp, narrowing of the passage section of the pipe 10, as an acoustic transmitting element, the waveguide is partially reflected towards the radiation source (towards the exhaust valve) and partially , go through the inlet pipe 10, enter the cavity of the pipe 10, covered by a continuous m cylindrical casing 24, openings 23, lose energy of a given frequency range in the resonator chamber 22 during friction resonant (with large amplitudes) gas oscillations and then through the inlet pipe 10 and an exhaust pipe (not shown) are released to the atmosphere.

However, the possible higher efficiency of the known design of the muffler (prototype) is not fully used, in

low frequencies - significantly worsens, with the occurrence of frequency bands of transmission of muffled sound energy due to the non-optimal distribution of camera volumes in the area of damping low sound frequencies, especially at the frequency of the main working harmonic of the internal combustion engine (exhaust pulse repetition rate), which causes additional transmission and emission of sound, from the muffler to the environment and does not satisfy the more stringent prospective requirements of draft national and international standards that limit external and internal The noise of vehicles.

The nature of the movement of exhaust gases, taking into account oscillatory processes at lower resonant frequencies, is determined by the fact that the volumes (masses) of gas in each of the intermediate pipes fluctuate as concentrated masses, while the volumes of gas in the silencer chambers work as elastic springs. The frequencies of these low-frequency oscillations in the silencer chambers depend on the total volume of gases in the silencer, the inertia of the gases, masses concentrated in the intermediate cavities, nozzles, and the distribution of the total volume of the silencer, and the longer the length of the nozzles (the mass of gases in the nozzles), the lower the natural frequencies oscillations of the cavities in the silencer chambers and the farther away they are from the forced frequency of excitation of the main working harmonic of the internal combustion engine (the frequency of the working process, i.e., the frequency of the exhaust pulses). The size of the maximum volume of the silencer chambers is limited by its layout, overall and cost indicators, the lengths of the intermediate pipes are also limited by the accepted length of the chambers, constrained by the layout of the pipes in the chambers, and, if necessary, their settings to effectively suppress sound emission at the resonant frequencies of the chambers. The ratio of volume chambers to each other should be selected according to the requirements of effectively damping the exhaust noise in such a way as to ensure the lowest values of the largest of the resonance frequencies corresponding to natural gas vibrations in natural forms (modes) with indices 1 and 2 (i.e., at the first and second own mods).

Computer simulation of acoustic and gas-dynamic processes taking place in the inventive device, according to the described structural scheme of the silencer, showed that it is rational, from the point of view, to ensure high efficiency of its (silencer) operation (ensuring high noise damping

mainly in the range of revolutions of maximum torque on the crankshaft of the internal combustion engine), there is a mutually agreed choice of the design parameters described above for the following reasons;

a) the length of each of the intermediate pipes must be at least half of the total length of the internal volumes of the intake, intermediate and exhaust chambers of the muffler;

b) the volume of the cavity of the intermediate chamber should be 0.57 of the total internal volume of the cavities of the intake, intermediate and exhaust chambers of the muffler (V);

c) the volume of the cavities of the inlet and outlet chambers separately should be 0.18 and 0.26 V, respectively.

For ratios coming out of the declared values (in either direction, since an increase in the volume of one of the cameras automatically reduces the volume of the other with the dimensions of the silencer body unchanged), the resonant frequencies are on the first or second eigenmodes (or both, or at least on one of them) - increase and at least one of them approaches the working frequencies of the excitation of the engine (the frequency of the exhaust pulses when the engine is running at maximum speed at the crankshaft), which affects the efficiency of silencing exhaust silencer in this important frequency range and high-speed engine operation due to the excitation and transmission of resonant gas vibrations from the chambers to the exhaust pipe of the muffler and then to the environment.

Thus, the design of a high-performance sound-damping multi-chamber exhaust silencer for ICE is implemented, due to the attenuation of resonant amplifications of sound energy at low frequencies (lower eigenmodes of the cavity of the silencer chambers), which ultimately reduces the acoustic pollution of vehicles equipped with piston ICEs.

Claims (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 divided by partitions, as well as connecting cavities of these chambers of the inlet, outlet and intermediate pipes, characterized in that the length of each of the intermediate pipes is not less than half of the total length of the internal volumes of the cavities of the intake, intermediate and exhaust chambers of the muffler, the volume of the cavity of the intermediate chamber is 0.57 of the total internal the volume of the cavities of the intake, intermediate and exhaust chambers of the silencer ("V"), the volume of the cavities of the intake and exhaust chambers of the silencer individually are 0.18 and 0.26 "V".