RU2270988C1 - Technological system for suppressing aero-gas-dynamic noise of forced suck-out of exhaust gases of test subjects like wheeled vehicles equipped with internal combustion engines, or autonomous internal combustion engines of testing acoustic complex - Google Patents

Abstract

FIELD: engineering of technological testing equipment and controlling-diagnostic equipment.

SUBSTANCE: technological system of internal combustion engine contains device for remote forced suck-out of exhaust gases of internal combustion engine in one of testing chambers of testing acoustic complex, testing chambers of testing acoustic complex contain, at least, two autonomous portions of outlet pipelines for exhaust gases from two testing chamber, while utilized technological system has common shared ventilation channel, equipped with air funnel plant and muffler, while to autonomous pipelines portions are connected to channel, belonging to separate testing chambers of testing acoustic complex, wherein stationary technological mufflers of aero-gas-dynamic noise are mounted, while at least in one of autonomous ventilation portions of pipelines of an individual testing chamber of testing acoustic complex exhaust gases of tested internal combustion engine are forced out without utilization of remote forced suck-out device elements and at least one of autonomous technological systems has body shaped as a rectangular parallelepiped, while internal side opposite walls of technological muffler body are lined with sound-absorbing panels, made porous sound-absorbing material. Inlet pipe of technological muffler is mounted on side wall of technological muffler body, and air funnel pipe of technological muffler is mounted on upper wall of technological muffler, while axes of inlet and outlet pipes are mutually perpendicular. Inlet pipe of aforementioned technological muffler is held in geometric center of side wall of technological muffler body. Air funnel pipe is rectangular in cross-section and is formed by end wall of technological muffler body, partially by its side walls and partially by bottom wall of body, and also mounted inside the body of technological muffler with space relatively to its bottom wall by additional internal wall, mated to side walls of body and parallel to adjacent end wall.

EFFECT: decreased acoustic pollution of environment.

1 cl, 8 dwg

Description

The invention relates to test technological and diagnostic equipment used in test acoustic complexes (IAC), in particular, to study the noise and vibration generated by an internal combustion engine (ICE) in the form of an autonomous power plant or as part of a vehicle, such as a car .

The solution to the problem of reducing acoustic pollution of the environment and improving the acoustic comfort of land wheeled vehicles is an important urgent task for developers and researchers of transport equipment, requiring large material, time and intellectual costs. The most mobile and productive research and development processes, in particular, wheeled vehicles in noise and vibration comfort, are experimental studies carried out in bench conditions, using a variety of techniques to simulate speed and load conditions identical to the road (field) test conditions (for example, dynamic stands with running drums), stationary measuring and analyzing equipment. Constant weather and road conditions independent of the test conditions, the convenience of taking and analyzing measurement information contribute to the wider spread of bench studies of vibro-acoustic processes in land wheeled vehicles. In view of the fact that the main vibro-noise source of a vehicle is its power plant — an internal combustion engine and, in particular, its gas exchange system (air-to-air system), including an intake system and an exhaust system for exhausting gas as the most intense gas-dynamic noise sources, it is very important to conduct their research and fine-tuning on a dynamic drum or motor tomotic stands when simulating various speed and load modes (changing the speed of the internal combustion engine, the opening angle throttle, etc.) under similar conditions close to the conditions of a free sound field (in which, for example, a vehicle is located on a freeway or field conditions during its operation).

A fairly complete imitation of the conditions of high-speed and load modes of a car’s movement and the operation of its internal combustion engine in real road conditions can be achieved on stands with running drums and motor stands, the practice of which is widely used in enterprises producing motor vehicles, in research institutes. It is possible to realize the conditions of a free sound field by placing these research stands in a special building - a semi-anechoic or anechoic acoustic chamber.

In this regard, modern research technologies of acoustic processes that are implemented on vehicles (cars, tractors, motorcycles and other types of wheeled vehicles) and their internal combustion engines include, in particular, the use of special designs (designs) of low-noise running drums, which allow simulating various high-speed and load operating modes of energy and transmission units of vehicles at low levels of noise produced by them, as well as having a low level of background noise mind of motor stands in the conditions of their placement in special anechoic or semi-anechoic acoustic chambers, which as a result contribute to the formation of a free sound field in measurement zones with a low level of acoustic noise.

Anechoic (completely muffled) or semi-anechoic (muffled, with a reflective floor) test chambers are rooms installed on a separate foundation, vibration-insulated from the main building. Such chambers house a dynamic stand with running drums (or a motor brake stand), which is vibration-proof from the main building and the camera body. The drive and brake installation are located in the basement or located on the same level with the camera, a separate engine room. To realize the acoustic properties of the camera to the conditions of propagation of sound waves identical to the conditions of a free sound field, directional matching of the acoustic impedances (resistance) of the air in the free space of the chamber in which the measuring microphones are located and in the porous structure of the sound-absorbing material lining (lining) sound-reflecting is performed surface of walls, ceiling, floor. That is why the design of the sound-absorbing lining of the walls (floor, ceiling) of the chamber is made porous and has a structural density of the porous structure, smoothly changing along the depth of the coating in the direction of propagation of sound waves to the hard sound-reflecting surface of the walls (floor, ceiling). Moreover, a higher density of the porous sound-absorbing lining is realized directly at the walls of the chamber, and lower - on the outer (receiving) surface layer of the sound-absorbing lining of the walls and ceiling of the test chamber. The necessary conditions for such a wave matching of the propagation and absorption media of sound waves in the lining areas of walls and ceilings are achieved, in particular, by using various wedge-shaped volumetric sound absorbers (in the form of wedges, wings). The main materials from which sound-absorbing lining absorbers are made are open-cell polyurethane foam, fiberglass, superthin basalt fiber, vinipore with fire-resistant impregnation, etc.

As a rule, modern IACs contain a family of test chambers (IR) - anechoic, semi-anechoic, reverberation, with dynamic drum, motor, transmission and other test benches installed in them, containing low noise drive and brake assemblies for various purposes of use in acoustic testing and tuning technologies objects. To eliminate the phenomenon of gas contamination by test objects - ICE, space of infrared and control room premises, technological systems (TS) of exhaust gas extraction are used, which are produced by test objects (wheeled vehicle, ICE), which are equipped with high-performance branched ventilation systems for local gas exhaust, with powerful fan exhaust installation, which exhausts the exhaust gases of internal combustion engines through individual pipelines and branched ventilation ducts Vehicle with their ejection (gases) in the environment. TCs, as a rule, contain a set of pipelines in the form of separate interconnected branched sections, on the one hand suitable for given zones of the space of the IR premises, and on the other hand, connected to a single pipeline with further connection with the outlet to a common ventilation duct, with the centralized mounted exhaust fan installation and silencer of the gas-gas dynamic gas flow, which reduces the levels of noise radiation produced by IAK in the open space (reduction of environmental pollution environment). In particular, in the patent of the Russian Federation for utility model No. 3327 (class 7 G 01 M 17/00, publ. 10.10.2003, Bull. No. 28) the design of a dynamic stand with running drums for acoustic research of vehicles, a technological suction system is presented the exhaust gas of which (see FIG. 1 of the description of utility model No. 3327) contains a flexible exhaust hose for exhaust gases with a sound-absorbing cover, a pipe for the technological exhaust gas system, a ventilation duct, a fan blower, and a technological plug s noise. In the known dynamic test bench with running drums, an autonomous exhaust system for exhausting a vehicle engine exhaust system is used with an airtight installation of a flexible exhaust hose of an exhaust ventilation unit on a free cut of the tail pipe of the main silencer of the vehicle exhaust system. This method of exhaust gas exhaustion during the implementation of testing and refinement technologies is used in cases where it is necessary to exclude the energy sound contribution from the total sound field of the studied object (vehicle, ICE) noise emission from the aerodynamic component of the noise of the exhaust system. This method and device for exhaust gas exhaustion is used, in particular, in research and development work on the purposeful separation of noise sources of a multicomponent emitter, studies of the noise of individual components and assemblies in a vehicle with the suppression of phonetic radiation of exhaust noise, and the preparation of equations for the acoustic balance of vehicle noise sources generally. At the same time, for example, when measuring the external and internal noise of the car, a rigid tight installation of the hose on the tail pipe of the muffler is unacceptable as excluding the process of sound emission by a free cut of the pipe into the open chamber, distorting the actual test results, since in this case it is excluded from the formation process The total (total) sound field of a car is one of its main components of noise sources (exhaust noise). On the other hand, the rigid damping connection of the additional mass of the hose to the track oscillating on the suspension to the body of the automobile exhaust system also causes undesirable changes in the dynamic loads on the supporting supporting rubber elements (suspension) of the exhaust system and, thus, distorts their real contributions from transmission by solid by vibro-acoustic energy to the structure of the floor of the body and further, in the form of air noise propagating inside the interior of the car in the form of internal noise of the car. In addition, the chemically active condensate contained in the exhaust gases of the structural elements (silencers) of the exhaust system of the automobile engine, freely entering the exhaust pipe of the exhaust gas vehicle, leads to subsequent intense corrosion of the vehicle pipelines. Therefore, when conducting this type of research (measuring the external and internal noise of automobiles), directly researching the noise-attenuating characteristics of the exhaust silencers of the vehicle under investigation, and performing finishing work to improve their designs, a flexible exhaust hose is not used. In this case, the engine exhaust is freely released (and the sound is emitted openly by the tail section of the pipe) into the open space of the acoustic chamber (see Walter Seeger publication "Geraususchabstrahlung eines Verbrennungsmotors. Einfluss der Ansaug - und Absauggerausche auf das Fahrzeug-lnngege-lnngege-lnngege-lnngege-lnngege." lndustrie, 1985, No. 5, p. 515). Or a flexible outlet hose is connected to a remotely mounted open conical bell mounted near an open free cut of the tail of the exhaust pipe of the vehicle under investigation (see utility model certificate of the Russian Federation No. 20399, class 7 G 10 K 11/00, B 60 N 1 / 00, published on October 27, 2001, Bull. No. 30). In this case, remote exhaust gas exhaust is realized and the free cut of the tail pipe of the silencer of the exhaust gas exhaust system of the internal combustion engine under investigation emits sound energy into the open space of the infrared. When using a low-noise low-capacity vehicle exhaust gas exhaust, the exhaust gas of the internal combustion engine exhaust system of the test vehicle is emitted into the acoustic chamber room, which leads to problems of excessive gas contamination of the room, partial loss of porosity and sound-absorbing properties of the sound-absorbing lining of the walls and ceiling of the IR due to subsidence on their surface particulate matter (soot) contained in the exhaust gases of the internal combustion engine of the test vehicles (in particular, equipped with diesel engine). When using a high-performance exhaust gas exhaust system, as a rule, a ventilation unit with a higher rotational speed and a larger impeller diameter is used, which inevitably leads to increased noise emission from this installation and the transmission of noise generated by it through a common ventilation channel to the connecting branches of individual sections of the suction vehicle duct pipelines in the direction of the open cut of the bell of the remote exhaust exhaust into the space of the test chamber. This, in turn, causes an undesirable increase in background noise noise in the measuring areas of the IR. In addition, while conducting research work in the IAK containing several infrared circuits with motor and dynamic drum stands installed in them, the transmission and redistribution of intense sound radiation through communicating pipelines (like acoustic waveguides) and noise mufflers built into these pipelines is possible "spurious" noise, for example, into the measuring zone of an open cut of the tail pipe of the exhaust system of the internal combustion engine located near the open cut of the bell tantsionnogo suction exhaust gases. Such transmission of noise energy can occur from the zones of the branched sections of the pipelines of vehicles of other IRs, combined into a single pipeline network with a common ventilation duct that exhausts the exhaust gas flow (in particular, when testing ICEs with exhaust gases released into the pipeline with options for dismantled standard silencers of the tested ICE or installed "sports" versions of exhaust systems with a high level of noise produced by them), with a high level of noise from simultaneously operating Olka test objects (internal combustion engine vehicles). In this regard, these silencers as components of a suction vehicle must have the property of reversibility, i.e. provide simultaneous suppression of the sound energy of waves from the input and output pipes of the muffler, effective damping of noise when changing the direction of the outflow of gases and the direction of propagation of sound waves from direct to opposite.

Thus, it is relevant to apply a technical solution to suppress and minimize the transmission of "spurious noise" through the connecting pipe branches of the vehicle exhaust exhaust, in particular, to the measuring point of the microphone at the free cut of the exhaust pipe of the muffler exhaust system of the internal combustion engine of a vehicle or other microphones located in the IR space, using low-noise remote exhaust suction devices emitted in the open air chamber space by a free cut of the tail pipe of the ICE of the vehicle being investigated, mounted on a stand with running drums. At the same time, such a vehicle for exhaust gas extraction should have high performance in order to prevent the occurrence of gas contamination by exhaust gases in the workspaces of infrared and control rooms. Thus, it is necessary to solve the contradictory task of using a high-performance (and, as a rule, quite noisy) fan (as part of a fan installation) in the exhaust gas exhaust engine of an internal combustion engine, with a highly efficient process of damping this fan noise, as well as effectively damping the noise of the exhaust gas flow ICE tested in other (neighboring) test rooms, ensuring low hydraulic resistance of communicating pipeline branches of exhaust gas exhaust and silencing elements ents in the vehicle and ensuring effective exhaustion of gases used by the fan unit. Technical devices for damping noise in the exhaust gas exhaust vehicle must also reduce the exhaust noise of the tested ICE transmitted to the environment and / or other test rooms through an open section of the pipeline for the common exhaust exhaust path. In particular, such silencing is most relevant in those cases when the direct-flow exhaust systems of exhaust engines (with dismantled silencers) are tested in the finishing processes and / or in the development and refinement of sports cars with forced engines, equipped, as a rule, with small-sized, simplified design , with low hydraulic resistance, ineffective exhaust silencing devices.

Thus, a complex compromise solution to the controversial technical problem is required, which is presented in the inventive device of the TS device for damping the aerodynamic noise of forced exhaust exhaust gas of the internal combustion engine, the design of which is presented in the materials of the claimed utility model.

The source of gas-dynamic noise of a vehicle for forced exhaust exhaust of vehicles and ICEs tested at machine test stations, scientific and technical centers of enterprises and research institutes, as a rule, are both directly fan units in the form of centrifugal fans, and the test objects themselves (vehicles, ICE) containing exhaust gas exhaust systems connected to branched (separated by specific test chambers) branches of the pipeline system in communication with local ondami suction of which is made fence gas environment with a single centralized local area of its discharge into the open space (environment). The sound energy generated by such a fan unit is also transported through the ventilation duct and to the infrared space via connected branched branches of pipeline sections, like acoustic waveguides, into the zones of their open sections located in the measuring spaces of acoustic semi-anechoic or anechoic chambers in which test benches and objects tested by noise (vehicle, ICE). In the event that the sound energy of the fan unit is not effectively damped by force, then a high noise spurious background will form in the measuring zones of the acoustic chambers, which will make it difficult to perform objective acoustic measurements with the test object (for example, the exhaust system of an engine, ICE, or vehicle generally). If the efficiency of damping the noise energy of the fan unit is not high enough, then the dynamic range of the acoustic measurements with the test objects will be narrow, or it will simply be impossible to make such measurements due to the high level of acoustic noise (comparable with the useful signal) (noise background). The use of highly efficient gas flow silencers, as a rule, is limited by the high hydraulic resistance created by them and, as a consequence, the insufficient efficiency of free exhaust exhaust of the internal combustion engine of the vehicle under investigation, which ultimately leads to increased gas contamination of the test chamber or the prohibition of the use of bench equipment for safe , health-hazardous working conditions for operators. The installation of a more efficient fan installation to overcome large hydraulic losses on the muffler, as a rule, leads to an increase in the noise generated by it.

There are various devices of noise-attenuating elements embedded as components of a gas exhaust vehicle and, in particular, a device for attenuation of noise produced by a fan installation, in particular, a centrifugal fan according to [1] - Japanese application 63-55400 cells. F 04 D 29/66, F 04 D 29/42, claimed 26.08.86. To ensure the effect of reducing the noise of a centrifugal fan as an element for generating sound radiation propagated through the connecting pipelines of the gas exhaust vehicle, a full or partial lining of the fan housing is provided with sound-absorbing material. The disadvantages of such a device for suppressing noise in a suction vehicle are:

- gas flow pulsations excited by the fan in turn excite their own acoustic modes of sections of the exhaust gas suction line as finite-length pipelines (waveguides) that enhance the transmission and emission of resonant noise both into the measuring zones of the acoustic chambers and into the environment;

- lining of fan case parts with sound-absorbing material is effective only for the purpose of attenuating fan noise exclusively in the medium and high frequencies of the sound spectrum and ineffective for suppressing the low-frequency pulsations generated by it and low-frequency sound;

- as a rule, the use of lining (lining) of fan case parts with porous materials is associated with an increase in the hydraulic resistance of the lined sections due to an increase in the friction of porous surfaces in contact with the suction gas flow, an increase in the cost of the structure as a whole, etc.

- the use of devices to attenuate noise generated directly by the fan, located directly in the vicinity of the fan zone or in its structure, cannot have the required positive noise-reducing effect on attenuation of sound energy generated and radiated into the environment by the exhaust systems of the studied ICEs and vehicles (in especially if the ICE and vehicles under investigation are noise-active, for example, equipped with once-through or “sports” systems, you OSCAL exhaust gas), whereby this sound energy (an exhaust gas from internal combustion engine exhaust systems tested) is usually more intense and excellent frequency content;

- the use of devices to attenuate the noise produced directly by the fan, implemented as part of the design of its casing, cannot have a positive effect on damping the noise and its unhindered transmission through separate freely connected sections of the pipelines of the branched exhaust system of several IRs arranged to the zone of the ventilation duct and fan installation, which can adversely affect the increased additional noise in individual IRs where low conditions are required noise background in the installation areas of the measuring microphones.

It is known, according to [2] - Tlumiki do wentilatorow zapylonych / Dyszlewska Krystyna / Zesz. nauk. Ciepl. masz. prsepl. /. Plodz. - 1987, No. 94, C.209 ... 220 (Polish), which is more rational to use resonant silencers to reduce the noise of the fans included in the pipelines of the gas exhaust system and providing the forced transportation of gases containing moisture and mechanical impurities. The disadvantages of the given designs of silencers, despite their structural simplicity, are their narrow-band and low-sound-damping ability, while in practical problems of suppressing noise in ICE exhaust exhaust pipes, it is necessary to use silencers effective in a wide frequency range, at least not less than than in the range of 63 ... 8000 Hz.

Known silencer as a component of sound attenuation of gases in the vehicle, installed on ventilation ducts, according to [3] - Norwegian patent No. 160027 (CL F 16 L 55/02), made in the form of an expansion cavity chamber, covering the perforated section of the duct. The space of the chamber formed by the outer casing and the perforated portion of the pipe is filled with fibrous sound-absorbing material such as mineral wool. An obvious drawback of such a silencer design is the need to use a large-diameter outer casing of the chamber with respect to the cross sections of the supply and exhaust sections of the air ducts in order to create a sharp (spasmodic) change in the wave resistances at the input and output of sound from the chamber (to ensure an efficient wave jam) and Thus, to provide conditions for the effective reflection of sound waves in the direction of the sound radiation source. In this case, the structure degenerates into a large-sized one, which is not always applicable according to the layout conditions, expensive and material-intensive. Also, due to the possible accumulation of chemically active condensate in the porous layer of the lower part of the muffler contained in the “hot” exhaust gases of the internal combustion engine, due to the influence of the “cold” walls of the large-sized casing (with improved heat removal due to the large surface area of the casing), a relatively rapid destruction of the casing is possible silencer, or the use of high-quality alloyed corrosion-resistant steel grades for the case material is required.

The muffler has similar design and operational drawbacks as a component of gas noise damping in the exhaust gas exhaust vehicle, made according to [4] - GDR patent No. 266936 (class F 01 N 7/13; F 01 N 1/24) in the form of a single-chamber cylindrical direct-flow design with coaxial inner perforated pipe. The annular cavity between the pipe and the housing is filled with fibrous material. The end cover of the housing on which the inlet pipe is mounted is removable for periodic replacement of the fibrous material when it is clogged with solid particles of the exhaust gases of the internal combustion engine.

Known silencer fan according to [5] - the patent of the Russian Federation No. 1574918 (CL F 04 D 29/66, F 01 N 1/08) for use in the suction and discharge channels of the fans of the vehicle TC transporting gaseous media, characterized by increased noise suppression efficiency. The silencer is made in the form of a hybrid sound-attenuating structure, including a combination of sound-attenuating elements in the form of a parallel-connected resonator chamber and a series-connected chamber with an active type sound-absorbing element in the form of a porous packing made of sound-absorbing material. The main drawback of this silencer design is its high hydraulic resistance associated with the series connection of an active type element in a pipeline vehicle, which generally degrades the efficiency of exhaust gas extraction and transportation through the vehicle pipelines and requires the use of a higher-performance ventilation unit (i.e., obviously, more noisy, dimensional and expensive), the presence of frequency regions of transmission of sound waves on the eigenmodes of the resonator chamber, weakening the overall noise damping effect.

As a PROTOTYPE, a low-noise vehicle of remote exhaust exhaust extraction for a dynamic stand with running drums was adopted, presented in the publication of the utility model description RU No. 30986, class. G 01 M 19/00, BI No. 19/2003. The utility model relates to control and diagnostic equipment, in particular, to a test bench for studying the noise and vibration generated by a motor vehicle, for example, a car. The well-known prototype proposed three options for the design of the vehicle remote exhaust exhaust for a dynamic stand with running drums used in acoustic testing of vehicles. In particular, the vehicle contains a forced-air exhaust exhaust ventilation system, a ventilation duct with exhaust gas to the surrounding atmosphere, exhaust vehicle pipelines, technological silencers (TG), a flexible exhaust hose with an attached open conical socket installed at a certain distance from the exhaust pipe cut. A distinctive feature of the known technical solution is the introduction of a spherical receiver-silencer into the design of the vehicle, lined with a sound-absorbing casing lining installed on the pipeline section of the exhaust exhaust system and located above the floor surface in the working space of a semi-anechoic acoustic chamber in contact with the IR floor and the walls of the pipe of the exhaust channel through a sealing vibration and sound insulating element. Various options for the design of the receiver-muffler and various predetermined orientations of the inlet pipe depending on the position of the open cut of the tail of the exhaust pipe of the exhaust system of the vehicle mounted on the running drums, allows you to mount a flexible exhaust hose of short length and minimal curvature of the hose axis connected to the open cone bell remote exhaust. At the same time, in the known vehicle for remote exhaust exhaust for a dynamic stand with running drums, it is ultimately envisaged to use three exhaust silencers in series connected to the exhaust exhaust path (see FIG. 1 of the above publication of utility model description RU No. 30986) : 14 - ball muffler; 20 - bench muffler and 20 - fan muffler. The series connection of three silencers adversely affects the deterioration of the hydraulic resistance of the exhaust gas path of the vehicle, which is ultimately associated with a deterioration in the efficiency of remote exhaust exhaust from the IR space and its possible excessive pollution, and also forces the use of a more efficient (ceteris paribus - noisier) fan installation 22. Also, despite the compactness of the used ball-type muffler 14, its use in indoor space IK is associated with the deterioration of the operating conditions of IK (clutter of the floor, excessive temperature heating of the muffler shell with hot exhaust gases and the need for its thermal insulation or forced airflow, the necessary introduction of additional detachable connections of the route to the connecting pipes of the ball muffler and the associated problems of using sealing elements to avoid gas leaks). The utility model descriptions of the utility model RU No. 30986 considered in the publication are designed for IAC with one test room equipped with an individual exhaust gas extraction system, in which, to ensure sufficiently efficient damping of the noise energy of the ICE exhaust gases and suppression of the ventilation noise of the ventilation unit, which provides forced exhaust exhaust, at least 3 mufflers in series are used, which impair others Under equal conditions, the hydraulic characteristics of the system and the efficiency of exhausting gases from a room with remote exhaust exhaust.

In the claimed design of the TS IAK for damping aerodynamic noise of forced exhaust exhaust, it is envisaged to use noise suppression devices for at least two IRs in a test complex, one of which is equipped with a remote exhaust gas. At the same time, the noise energy of the exhaust gases coming from each IR IAC is muffled by two TGs connected in series (exhaust and fan) and one parallel connected TG installed in the pipeline branch of the neighboring IR. Those. Pipe branches with a silencer for each of the IRs drown out the noise energy of the exhaust not only directly from the test object installed in this particular IR, but also dissipate the noise energy of the test object from the neighboring IR. In addition, the claimed design of the bench-mounted TG is optimized in acoustics, hydraulics, durability, mounted under the floor (which also eliminates the emission of body noise by the walls of the silencer in the IR room, allows the use of fewer connectors, seals, etc.).

Test objects in the form of wheeled vehicles equipped with a power plant of the ICE type, mounted on dynamic stands with running drums in the IR and ICE mounted on the engine brake stands in the IR, have a common vehicle for removing (sucking) exhaust gases into the environment. Such a vehicle for forced exhaust exhaust contains individual pipelines for forced exhaust exhaust for internal combustion engines with branching sections of pipelines, a common ventilation channel for forced exhaust exhaust for internal combustion engines, exhaust fan installation, exhaust pipe, TG aerogasdynamic noise, mounted both on sections of individual pipelines, and in general ventilation duct. The vehicle operates a forced exhaust exhaust as follows. The test object mounted on the test bench (vehicle - on running drums, ICE - on the brake motor stand) is subjected to an acoustic test process with the implementation of the working process in the ICE cylinders, with the corresponding exhaust processes, accompanied by the processes of removing exhaust gases from the combustion chambers, generating and the propagation of acoustic (sound) waves, which are transported initially along the discharge pipelines or through regular piping elements of the exhaust system exhaust gases from the studied object (ICE), and then fall into the standard elements of the vehicle forced exhaust exhaust gas, propagating through individual branched communicating pipelines and TG TS forced exhaust exhaust gas, enter the common ventilation channel of the forced exhaust vehicle TS from the TG, which is connected to a fan installation, creating a forced additional movement of exhaust gases with their subsequent discharge through an exhaust pipe into an open atmosphere with a damped m internal combustion engine exhaust noise test (ICE vehicles). Due to the fact that the technological process of acoustic tests in the IAC according to the claimed technical solution is carried out with several test objects (at least two) located (dispersed) in different test rooms, which are interconnected by appropriate pipeline branches, at least in one from IAC IAC, a remote exhaust exhaust is used from an open (free) cut of the tail pipe of the muffler of the exhaust system of the internal combustion engine of the test vehicle At least in another IK IAK - the internal combustion engine is subjected to a technological test process, which is not equipped with effective exhaust gas silencers (for example, a noise-free direct-flow or “sports” exhaust system is mounted), as a result of intensive transmission of sound energy from the exhaust noise this internal combustion engine through communicating pipeline channels - from an open socket of a remote vehicle exhaust exhaust located in the infrared with the test vehicle installed, from a free cut An open bell of the remote exhaust suction emits additional sound energy that increases the noise background in this IR. The sound energy generated by the exhaust processes of the tested ICE during direct-flow or “sports” exhaust systems is sequentially damped by at least two TGs located in the individual pipeline branches of each of the IRs from one IR to another. The implementation of the exhaust silencers of the claimed design as exhaust silencing components of the tested ICE of the vehicle of the claimed design makes it possible to effectively block the transfer of exhaust energy to the infrared with a remotely located exhaust pipe generated by the internal combustion engine of a vehicle mounted on running drums.

The essence of the invention lies in the fact that in the known vehicle for damping aerodynamic noise of forced exhaust exhaust from test objects such as wheeled vehicles equipped with internal combustion engines, or autonomous internal combustion engines IAC, including a remote forced exhaust exhaust from internal combustion engines in one of the IR IAC connected to a common ventilation the channel equipped with a fan exhaust installation and a noise TG contains at least two autonomous sections of the exhaust pipes from two IR, and the TS used contains a common ventilation channel to which autonomous ventilation sections of the pipelines of individual IR IACs are connected, in which stand TGs of aerodynamic noise are mounted, while in at least one of the autonomous ventilation sections of the pipelines of a separate IR IAC, the exhaust gases of the tested ICE are exhausted without the use of elements of a remote forced suction device, and at least one of the autonomous TG TS has the shape of a body in the form of a rectangular parallel a lepiped, the length of the smallest of the ribs of which forming the bottom wall of the body is at least two times shorter than the other two ribs forming the side and end walls and having the same length, while the inner side opposite walls of the TG body are lined with sound-absorbing panels made of porous sound-absorbing material, for example, an pressed layer of fiberglass or basalt fiber, the thickness of which is h = (0.1 ... 0.25) of the length of the smaller edge of the rectangular parallelepiped, the supply pipe TG is it is mounted on the side wall of the TG case, and the exhaust pipe of the TG is mounted on the upper wall of the TG, while the axes of the supply and exhaust pipes are mutually perpendicular, the supply pipe of the TG is fixed in the geometric center of the side wall of the TG case, and the gap between its free cut placed in the cavity the casing chamber and the outer surface of the sound-absorbing panel placed on the opposite side wall of the casing is c ₁ = (0.3 ... 0.5) d ₁ , where d ₁ is the diameter of the inlet section of the supply pipe, the exhaust pipe has a straight cross section is angular in shape and is formed by the end wall of the TG case, partly by its side walls and partly by the bottom wall of the case, as well as mounted inside the TG case, with a gap relative to its bottom wall, an additional inner wall, conjugated to the side walls of the case and parallel to the adjacent end wall, and the surface elements of the TG walls forming the exhaust pipe are lined from the inside with a layer of porous sound-absorbing material lined with perforated metal sheet or wire with a grid, while a vertical partition is mounted on the bottom wall of the TG case, parallel to the end and additional inner wall, with a gap in relation to it, with the formation of a labyrinth channel connecting the cavity of the TG case with the cavity of the exhaust pipe, in addition, on the outer surfaces of sound-absorbing panels side walls mounted perforated sheet or wire mesh. Additionally, a vertical partition mounted on the bottom wall of the TG case can be lined with a layer of porous sound-absorbing material lined with perforated metal sheet or wire mesh.

Sound-absorbing panels with respect to the bottom wall of the TG case can be installed with a gap. On the bottom wall of the housing, parallel to the surfaces of the sound-absorbing panels and with a gap to it, vertical ribs can be mounted, for example, formed by the side surface of the shelves of the corners welded to the bottom. A drain plug may be mounted in the bottom wall of the TG housing.

The invention is illustrated graphically.

Figure 1 and 2 presents the IAK with separate rooms of the acoustic chambers with the claimed vehicle silencing aerodynamic noise. The positions in figure 1 are indicated:

1 - semi-anechoic acoustic chamber (IR) with a dynamic drum stand installed in it for the study of wheeled vehicles;

2 - anechoic acoustic chamber (IR) with a motor stand installed in it for ICE research;

3 - reverberation acoustic chamber (IR) with a motor stand installed in it for ICE research;

4 - sound-absorbing backstage;

5 - running drums of a dynamic stand;

6 - brake (drive) installation of the motor stand;

7 - test wheeled vehicle (test object);

8, 9 - investigated ICE (test objects);

10 - exhaust pipes of the internal combustion engine;

11 - a free cut of the tail pipe of an automobile muffler;

12 - measuring microphone;

13 - open conical bell of the remote exhaust exhaust engine;

14 - pipelines TS forced exhaust exhaust engine;

15 - branching of pipeline sections;

16 - the general ventilation channel of the vehicle forced exhaust exhaust engine;

17 - fan exhaust installation of the vehicle forced exhaust exhaust engine;

18 - exhaust pipe TS forced exhaust exhaust engine;

19, 20 - bench TG aerodynamic noise;

21 - fan TG aerodynamic noise.

Figure 3 and 4 presents a diagram of one of the possible variants of the design of the bench TG TS silencing aerodynamic noise presented in figures 1 and 2.

Figures 5 and 6 show a diagram of the installation of sound-absorbing panels in the lower (bottom) part of the TG chamber with the exception of the process of intensive impregnation of the ends (and the whole structure) of the porous layer of sound-absorbing panels, condensate accumulated in the bottom of the TG and a device for its forced removal.

Figs. 7 and 8 show a further constructive development of the TG device shown in Figs. 3 and 4.

TG TS muffler aerodynamic noise (see figure 3 and 4) contains a metal casing (chamber) 22, made in the form of a rectangular parallelepiped, one rib b ₃ which is at least 2 times less than the other two ribs b ₁ and b ₂ :

b ₃ <0.5b ₁

b ₃ <0.5b ₂

The ribs b ₁ and b _{2 are} made of approximately the same length, which realizes a larger volume of the TG chamber with the same maximum overall dimension that determines the lowest eigenmode (fewer lower eigenmodes are realized due to the coincidence of their values in height and length of the chamber). The flat opposite inner surfaces of the side walls 23 and 24 of the chamber, perpendicular to the smaller rib b ₃ , are lined with sound-absorbing panels 25 made of porous sound-absorbing material, for example, such as pressed fiberglass, basalt fiber. This significantly weakens the longitudinal resonances that are realized in the cavity of the hollow chamber along its long ribs, since the waves running along these ribs are effectively attenuated by the porous sound-absorbing lining of the panels 25. The thickness of the sound-absorbing panels h = (0.1 ... 0.25) b ₃ . Such a choice of thickness h does not significantly reduce the volume of the TG chamber necessary for efficiently damping noise in the low-frequency range, and at the same time provides a sufficiently high absorption of sound waves in the medium and high frequencies by the porous layers of panels 25 emitted from both the side of the fan exhaust system 17, and from the side of the gas-dynamic flow of exhaust gases studied by the internal combustion engine. A supply pipe 26 is introduced through the geometric center of the side wall 23 of the TG case into the cavity of the TG chamber. A small depth entry of the free cut of the supply pipe 26 into the cavity of the TG chamber eliminates noticeable losses in the free volume of the chamber cavity (a larger “working” volume of the cavity of the TG expansion chamber is realized). On the other hand, this input zone of the free cut of the supply pipe into the chamber cavity is characterized by the localization in it (air cavity) of the nodes (minima) of the pressures of the lower odd eigenmodes, in particular, the first and third as the most energy-intensive. As a result, these eigenmodes are not dynamically excited by the dynamic free cut of the supply pipe 26 located in the assembly, which eliminates the appearance of low-frequency dips (acoustic holes) in the TG noise suppression characteristic of the indicated eigenmodes. It should be borne in mind that the efficiency of low-frequency sound absorption by porous sound-absorbing materials of panels 25 is still not high enough (weak) and the exclusion of excitation of the indicated low-frequency resonance modes in the TG chamber is therefore an effective technique that increases the noise attenuation characteristics of TG as a whole. Also, a hard circuit of the side wall 23 by the supply pipe 26 with a weld 27 in the zone of its entry into the wall, as the most dynamically pliable zone (in the center of the plate, the bending stiffness is minimal), helps to weaken the case vibrational noise of the TG excited by gas-dynamic gas pulsations and mechanical vibrations connected to the pipe body. The gap c ₁ between the free cut of the supply pipe 26 and the surface of the porous sound-absorbing material from the side of the opposite wall of the casing is c ₁ = (0.3 ... 0.5) d ₁ , where d ₁ is the diameter of the passage section of the supply pipe 26. In this case, the sound generated a free cut of the supply pipe is well absorbed by the porous lining of the panel 25 due to the selected location of the sound-absorbing material of the panel 25 in the zone of high concentration of sound cut-off energy (high amplitudes of vibrational velocities of the gas flow), and on the other hand, the loss time to the gas stream and the TS hydraulic resistance is relatively small. Indeed, taking into account the dynamic elongation of the pipe (i.e., taking into account the added mass of the gas oscillating in the free section) equal to (0.1 ... 0.3) d ₁ , the gap c ₁ between the section and the surface of the sound-absorbing material is (0.3 ... 0.5) d ₁ is already large enough to exclude the deterioration of the hydraulic resistance of the vehicle in the section of the pipe with a nearby wall (not affecting the near hydrodynamic field), and the free section emitting sound (high concentration of sound energy) is close to sound-absorbing th porous structure, which contributes to the process of more efficient absorption of sound. The exhaust gas exhaust is organized using an exhaust channel 28 in the form of a rectangular parallelepiped formed by a smaller side wall of the TG body, part of the walls 23 and 24 and an inner wall 29 mounted in the cavity of the TG chamber. The large walls of the exhaust channel 28 and its lower part (bottom) are lined from the inside a layer of porous sound-absorbing material 30, lined with perforated metal sheet or wire mesh 31. A partition 32 is mounted in the cavity of the TG case (for example, a metal plate) birint inlet of the gas flow into the exhaust channel 28. Such a design of the TG is simple to manufacture and facilitates the final adjustment of the location of the free pipe sections in the cavity of the TG chamber to obtain maximum values for damping the noise (eliminating “dips” in the damping characteristics at individual frequencies of the sound spectrum). Figures 7 and 8 show a variant of the TG design when the vertical partition mounted on the bottom wall of the silencer body is lined with a layer of porous sound-absorbing material lined with perforated metal sheet or wire mesh.

On the outer surfaces of the sound-absorbing panels 25, a perforated metal sheet 33 is mounted that performs a bearing function and at the same time does not impair the sound-absorbing characteristics of the porous material of the panels 25 due to the high value of the perforation coefficient of the sheet. As an option, instead of perforated sheets, cladding of sound-absorbing panels with wire mesh is possible. In the lower part of the TG chamber, sound-absorbing panels 25 are installed with a small gap with respect to the bottom wall 34 of the TG case (see Fig. 5). The absence of adsorption material on the bottom of the TG body and the presence of a gap between the ends of the sound-absorbing panels and the bottom wall 34 is a positive factor from the point of view of ensuring a higher durability of the TG and providing more stable noise-attenuating characteristics. As a result, condensate and mechanical particles are deposited on the bottom (bottom panel), and as a result, the absence (decrease in quantity) of these substances in the structure of the porous layer of sound-absorbing panels is noted. Alternatively, it is possible to install welded corners 35 on the bottom panel 34 of the TG body (see FIG. 6). In this case, installation of the ends of the sound-absorbing panels 25, which is clearance-free with respect to the bottom of the TG, is possible, and the protection of the bottom of the ends of the porous sound-absorbing panels from the accumulating condensate 36 is provided by the surface of the corners 35. A threaded drain plug 37 can be mounted in the bottom panel 34 of the TG case to allow periodic drainage condensate accumulated in the TG chamber 36.

Claims (5)

1. Technological system (TS) for damping aerodynamic noise of forced exhaust exhaust from test objects such as wheeled vehicles equipped with internal combustion engines (ICE) or autonomous ICE of a test acoustic complex (IAC), including a remote forced exhaust pump of ICE exhaust in one of the IAC test chambers (IR) connected to a ventilation duct equipped with a fan exhaust system and a noise muffler, characterized in that the IAC TS will contain at least two autonomous sections of the exhaust gas pipelines from two IRs, while the TS used contains a common ventilation duct to which the independent ventilation sections of the pipelines of individual IR IACs are connected, in which there are mounted process silencers (TG) of aerodynamic noise, at this, at least in one of the autonomous ventilation sections of the pipelines of a separate IR IAC, the exhaust gases of the tested ICE are removed without the use of elements of the device forced suction, and at least one of the autonomous ТГ ТС has the shape of a body in the form of a rectangular parallelepiped, the length of the smallest of the edges of which forming the bottom wall of the body is at least two times shorter than the other two edges forming the side and end walls and having the same length, while the inner side opposite walls of the TG case are lined with sound-absorbing panels made of porous sound-absorbing material, for example, an extruded layer of fiberglass or basalt fiber, whose thickness is h = (0.1 ... 0.25) of the length of the smaller edge of the rectangular parallelepiped, the supply pipe TG is mounted on the side wall of the housing TG, and the exhaust pipe TG is mounted on the upper wall of the TG, while the axis of the supply and exhaust pipes are mutually perpendicular, the supply pipe TG is fixed in the geometric center of the side wall of the housing TG, while the gap between its free cut placed in the cavity of the camera housing and the outer surface of the sound-absorbing panel placed on the opposite side wall to rpusa is c ₁ = (0.3 ... 0.5) d _1, where d ₁ - diameter of the passage section of the inflow pipe, exhaust pipe has a rectangular cross-sectional shape and is formed by the end wall of the housing TG partially its sidewalls and bottom wall of the housing part and also mounted inside the TG casing, with a gap relative to its bottom wall with an additional internal wall, conjugated with the side walls of the casing and parallel to the adjacent end wall, and the above-mentioned surface elements of the TG walls forming from the inside from the inside lined with a layer of porous sound-absorbing material lined with perforated metal sheet or wire mesh, with a vertical partition mounted on the bottom wall of the TG casing parallel to the end and additional inner wall with a gap with respect to it, with the formation of a labyrinth channel connecting the cavity of the TG casing with the cavity exhaust pipe, in addition, on the outer surfaces of the sound-absorbing panels of the side walls mounted perforated sheet or wire mesh. 2. The technological system for damping aerodynamic noise according to claim 1, characterized in that the vertical partition mounted on the bottom wall of the TG body is lined with a layer of porous sound-absorbing material lined with perforated metal sheet or wire mesh. 3. The technological system for damping aerodynamic noise according to claim 1, characterized in that the sound-absorbing panels with respect to the bottom wall of the TG case are installed with a gap. 4. The technological system for damping aerodynamic noise according to claim 1, characterized in that on the bottom wall of the housing parallel to the surfaces of the sound-absorbing panels and with a gap to it are mounted vertical ribs formed, for example, by the side surface of the shelves welded to the bottom of the corners. 5. The technological system for damping aerodynamic noise according to claim 1, characterized in that a drain plug is mounted in the bottom wall of the TG body.

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