RU43070U1 - ACOUSTIC MOTOR STAND FOR RESEARCH AND FINISHING WORKS TO MUTE THE NOISE OF THE INLET OF THE INLET OF THE INTERNAL COMBUSTION ENGINE - Google Patents

Abstract

The utility model relates to control and diagnostic equipment, in particular, to a test bench for bench research and development work on damping the noise of the intake system of internal combustion engines (hereinafter ICE).

The motor stand, with the research object mounted on it - ICE with mounted units, is installed in an anechoic chamber with a soundproof floor.

New is that the ICE case with mounted assemblies is covered by a soundproof casing mounted directly on separate areas of the ICE case, on the supporting elements of the ICE fastening devices on the stand, and on a separate support stand mounted on the supporting elements of the soundproof floor of the anechoic chamber by bolted connections through vibration dampers. In this case, the bearing shell of the casing is made in the form of a continuous or perforated thin-walled metal sheet (preferably from an easily deformable metal — aluminum, copper, lead), or from a similar material of a metal wire mesh. The outer surface of the bearing shell of the casing is felt with porous sound-absorbing material with a protective sound-transparent layer. In addition, in the structure of the casing, a communication interface hole is made, with the air intake manifold of the ICE intake system air cleaner passing through the structure of the casing and tightly and intrinsically enclosing it in the interface zone with the casing with an elastic rubber, porous foam or fiber seal and providing a free sound-emitting nozzle the air cleaner outside the space covered by the casing of the engine housing with mounted units assembled.

The practical application of the acoustic motor stand claimed as a useful model for research and development work on damping the noise of an internal combustion engine intake system allows one to reduce the negative impact on the processes of objective measurements of the sound radiation of the investigated noise produced by the internal combustion engine intake system by isolating the noise radiation of "extraneous noise sources" in point (s) of measurements, i.e. to increase the dynamic and frequency range of measurements of directly studied acoustic parameters of the ICE intake system (sound radiation of the ICE intake system) and, thus, increase the accuracy and objectivity of the estimates made. In addition, the measuring microphone is protected from the effects of high temperatures if the microphone is located near the thermally loaded parts of the internal combustion engine.

Description

The utility model relates to control and diagnostic equipment, in particular, to a test bench for bench research and development work on damping the noise of the intake system of internal combustion engines (hereinafter ICE).

During experimental design work (R&D) during the development, research, development and production of ICE structures, bench testing of ICEs was widespread. In the range of research and development work during bench tests of ICEs, an important place is occupied by damping the gas-dynamic and body noise of the ICE intake system, which is one of the main sources of excitation and radiation of acoustic energy (into the environment or the cabin (cabin) of a vehicle using ICE as power plant). Modern technologies for vibro-acoustic research and development of ICE structures involve the use of special building structures in the form of vibration-proof anechoic or semi-anechoic acoustic chambers, low-noise drive (brake) mechanisms of the stands, various devices for functioning and controlling the work of the stand, measuring and analyzing equipment

As basic equipment, the ICE test bench contains:

- an autonomous (vibration-insulated) foundation for absorbing vibrations arising from the action of unbalanced forces and moments of inertia in the engine;

- foundation plate (groove) for installing the investigated engine and brake;

- racks for installing and fixing ICE on a foundation plate;

- a load brake (hydraulic, electric) to absorb the power developed by the internal combustion engine with a torque measuring device on the motor shaft (brakes);

- a shaft and special couplings for connecting the ICE crankshaft to the brake shaft;

- devices and communications for supplying a cooled lubricating oil, engine coolant to the engine cooling engine, exhaust into the atmosphere of exhaust and crankcase gases of the engine;

- devices and communications for powering the engine with fuel and air with appropriate sensors and devices for measuring flow, temperature, air and fuel pressures;

- special devices for regulating and determining individual parameters that affect the working process and ICE indicators (ignition timing, composition of the mixture, timing of the timing of the start of injection);

- systems providing regulation and control of ICE in the process of testing;

- remote control with the start-up and control elements of the internal combustion engine;

- instruments for monitoring the operation of the engine and instruments for recording measured values;

- additional devices and devices intended for special studies in order to determine the individual parameters of the internal combustion engine (toxicity, smoke, noise, vibration, thermal tension, deformation of individual parts, etc.).

For conducting vibroacoustic bench research and development work on internal combustion engines, specialized load stands installed in special acoustic (semi-muffled or anechoic) chambers [for example, 1, 2, 3, 4] are widely used:

[1] Adam Gavine. The American Way. Testing Technology International, November, 2000, p. 28.,. 31;

[2] GUP NITSIAMT “The acoustic center will perform:”. Automotive Industry, 2000, No. 11, 1.

[3] Peter Brandstatt, Helmut V. Fuchs, and Manfred Roller. Novel silencers and absorbers for wind tunnels and acoustic test cells. Noise Control Eng. J. 50 (2), 2002 Mag-Apr, 41-49.

[4] Peter Gutzmer und Reimer Pilgrim. Motorakustische Versuchs-und Meptechnik bei Porsche. MTZ, Motortechnische Zeitschrift, 48 (1987), 2, 47 ... 50.

In particular, in [1] an example of using a semi-muffled acoustic camera of the Chrysler company (USA) is given, in [2] - an acoustic motor stand of the Central Autopolygon GUP NITSIAMT (Dmitrov, Moscow Region) with a hard sound-reflecting floor, on a groove plate which with the help of special racks the studied ICE is fixed. The brake (or drive - in the engine scrolling modes without implementing the workflow in it) bench installations (there are 2 of them) are located at the same level outside the acoustic chamber and are located outside the chamber walls in the adjacent room (machine room). The ICE under study with a brake balancing machine is connected using special drive shafts (power take-off shafts), which transmit torque or braking torque between them. The end sections of the drive shafts are fixed with special racks to the groove plate and directly to the surface of the chamber floor. Pipelines and various communication elements of the power supply, cooling, and exhaust gases are removed from the space of the acoustic chamber through special soundproof openings in the floor (groove plate) of the chamber to the machine room of the stand, equipped with various technological systems and units for ensuring the functioning of the stand. The disadvantages of the used concept of an acoustic motor stand is the use of a camera with a hard sound-reflecting floor that distorts the real sound field of the ICE under study (in particular, sound emission from the lower part of the ICE located in the immediate vicinity of the sound-reflecting floor surface, which, as a rule, is common for all piston ICEs most noise-vibrating). It is in this connection that the lower engine zone is of the greatest practical interest for ICE researchers and closers and requires the most time-consuming and, if possible, the most accurate and objective studies to be carried out in this zone. On the other hand, the use of long driveshafts with thrust bearings in vertical struts mounted on a groove, as connecting drive elements connecting the crankshaft of the internal combustion engine and the power shaft of the brake machine of the stand

the plate and directly to the floor of the chamber, it causes problems of their alignment with the crankshaft of the ICE under study, and, as a result, the generation of vibrational forces at the frequencies and ordinal harmonics of their rotation transmitted through reference links to both the ICE directly under investigation, causing its additional noise emission, and some connected structures of the acoustic chamber (for example, the floor of the chamber), which entails additional distortion of the recorded noise characteristics of both the ICE under study and the emission of “spurious” sound directly enno protective housings of the stand rolls, as well as radiation "parasitic" sound directly hollow acoustic chamber, due to transmission of vibration excitation of the floor (slab slots) through the support legs shafts.

Acoustic motor stand f. BMW (see [3]) contains a completely anechoic chamber, and the ICE under study is mounted on a soundproof grating floor, which makes it possible to conduct qualitative studies of noise radiation from the lower part of the ICE. The brake installation is on the same level with the internal combustion engine in an adjacent room behind the wall of the anechoic chamber. The disadvantage, as in [1], [2], is the use of a long shaft as a connecting connection, which causes problems of its alignment with the crankshaft of the ICE under study, and, as a consequence, the generation of vibro-forces at the frequencies and ordinal harmonics of their rotation transmitted through reference links directly to the internal combustion engine under investigation, causing its additional noise emission.

A more progressive method for studying and recording the acoustic energy emitted by ICE under bench conditions is to use the concept of an acoustic motor stand described in publication [4] used in the Porsche Research Center (Germany). In this case, it provides for the use of a brake (load) stand installed in the center of the chamber below the floor surface of a completely muffled anechoic acoustic chamber. The transmission of torque (braking) is carried out with an endless flexible connection - smooth transmission. In this case, the floor of the acoustic chamber is made completely vibration-proof from an autonomous foundation on which a drive (brake) stand is installed, and its surface (floors) is covered with effective sound-absorbing material (special sound-absorbing wedges). The engine housing, as an object of study, in this case is located near

the geometric center of the airspace of the camera, i.e. in the zone farthest from sound-reflecting surfaces (with “best acoustics”). The lower zone of the ICE under study is not located near the sound-reflecting surface of the floor, as was the case in [1] and [2], but is open to qualitative, objective measurements of the acoustic field parameters of the ICE under study.

From the German patent DE 4019581 A1 - [5], the design of the test bench f. BMW for research and development work on a gas-dynamic engine noise source - exhaust system. The test bench is presented in the form of a complex of two chambers, with the output of the exhaust route into a separate anechoic room. A significant drawback of this design is the complexity and high cost of the building structure, the complexity of the layout of the exhaust route, the impossibility of multi-purpose (universal) use of this test chamber. Sound radiation by a free cut of the exhaust pipe of the exhaust system under study is produced in a muffled chamber of relatively small size (volume), which is unfavorable from the point of view of obtaining objective measurement results due to the formation of the intense contribution of the reflected acoustic field (in comparison with sound radiation in the space of large-sized cameras).

Known acoustic motor stand, which is part of the device for assessing the level of body noise ICE, a description of which is given in [6] certificate of utility model of the Russian Federation No. 20804, 11/27/2001, Bull. No. 33, accepted as a PROTOTYPE. In this case, the described device for estimating the internal noise level of an internal combustion engine, containing a set of vibro-acoustic, measuring, analyzing and recording equipment, the object of research is an internal combustion engine mounted on a test bench in an anechoic acoustic chamber with supply and exhaust ventilation, an exhaust system that is hermetically discharged into the technological exhaust system of the exhaust gas of the test bench, and the impeller of the engine cooling system fan, brought into an inoperative state - which, in combination, provides The contribution of the levels of the gas-dynamic component of the noise of the ICE intake system at the points of installation of the measuring microphones located around the ICE case due to the hermetic connection of the open cut of the air intake pipe of the air purifier with a flexible hose that takes air into the ICE from the cavity of the nozzle for supplying ventilation of the acoustic chamber. At the same time, in the practice of research and development

of works on vibroacoustic ICE often have to solve the exact opposite problem - to exclude the contribution of the levels of body noise ICE, during research and development work on the acoustics of the elements of the intake system of the engine. This is necessary for a qualitative and quantitative assessment of sound radiation produced by elements of the internal combustion engine intake system and, in particular, gas-dynamic noise produced by an open cut of the intake pipe of the air cleaner of the internal combustion engine intake system, while significantly reducing the noise of “extraneous acoustic noise” to obtain objective estimates in a wider dynamic and frequency ranges. In this case, “extraneous acoustic interference” is the sound radiation produced by the vibrating surfaces of the ICE body and the vibrating walls of the mounted auxiliary ICE units. Known acoustic motor stands, the design of which is presented in [1] - [b], do not contain specialized devices and technologies to provide the required high sound insulation of body noise in research and development technologies for evaluating the effectiveness of noise suppression devices of the ICE intake system. Namely, to solve this technical problem, an acoustic motor stand is designed, the design of which is presented in the claimed utility model.

Known designs of soundproofing screens designed to drown out the noise of "extraneous interference" when performing research on the evaluation of the noise sources of internal combustion engines. In particular, in [7] - Everett Armold and Warner Frazer (Detroit Diesel Corp.), W.J.J. Hoge (Noise Cancellation Technologies, Inc.). Development of a Prototype Active Muffler for the Detroit Diesel 6V-92 TA Industrial Engine. SAE article No. 911045, pp. 57-66, presents the design of a noise-insulating screen (see Fig. 3, 5 of this publication), used in the study of the noise of the exhaust system of a diesel engine 6V-92 TA, for insulation of engine body noise. The screen is made in the form of a rectangular wooden shield lined with a layer of porous sound-absorbing material with a thickness of 25 mm. The disadvantage of this screen is its rigid large-sized design, which does not make it possible to use the screen for sound insulation of engine ICE noise in technologies for studying the gas-dynamic noise of the ICE intake system, in particular, compact designs of the intake systems, in cases where a free cut of the intake pipe is located directly near the ICE case (for example, short inlet hoses and nozzles or inlet elements are made in

as a single module).

The essence of the utility model lies in the fact that in a known acoustic motor stand installed in an anechoic chamber with a soundproof floor containing, in particular, a load brake, mechanical coupling elements of the ICE shaft with the load brake shaft, sets of control, measuring and analyzing equipment, the object of study - ICE with mounted assemblies assembled on a stand with the help of supporting all-metal longitudinal and transverse rails and all-metal racks, - ICE case with mounted ag regattas are covered by a soundproof casing mounted on the elements of the ICE fastening device on the stand, as well as on a separate support stand installed on the supporting elements of the soundproof floor of the anechoic chamber by means of a bolt connection through vibration dampers; in this case, the bearing shell of the casing is made in the form of a continuous perforated or thin-walled metal sheet (preferably of easily deformable metal - aluminum, copper, lead) or a similar material of a wire metal mesh, and the outer surface of the bearing shell is lined with a porous sound-absorbing material with a protective sound-transparent layer;

the structure of the casing contains a hole for interfacing with the intake pipe of the air purifier of the ICE intake system, tightly and intrinsically covering it through the use of an elastic rubber, porous foam or fibrous sealant. At the same time, a free sound-emitting section of the intake pipe of the air cleaner of the intake system is located outside the space covered by the casing of the ICE housing with mounted assemblies, i.e. in an area where a lower noise background from extraneous noise sources (ICE with mounted units) is provided. An external sound-absorbing lining of the casing provides a weaker reflection of sound waves emitted directly by a free cut of the pipe of the air cleaner. Thus, the conditions for ensuring a wider dynamic and frequency range of inlet noise studies are realized. The measuring microphone is installed directly near the sound-emitting free cut of the intake pipe of the air cleaner of the ICE intake system (the distance from the microphone to the cut of the pipe is determined by the specific technological procedure of the researcher).

The essence of the utility model is illustrated in the drawings.

Figure 1 shows a completely muffled anechoic acoustic chamber in which an acoustic motor stand claimed as a utility model is installed for research and development work on damping the noise of an internal combustion engine intake system.

Figure 2 presents a fragment of the design of the proposed acoustic motor stand for research and development work on damping the noise of the intake system of the engine, comprising a device for attaching the engine to the stand with a mounted soundproof casing.

Figure 3 shows the installation diagram of a separate rack for attaching the soundproof casing to the translucent floor of the test chamber.

Figure 4, 5, 6 presents the structural components of the soundproof casing.

In Fig.7 shows a fragment of a soundproof casing with a hole pairing with the air intake pipe of the air purifier of the engine intake system.

The utility model shown in Fig. 1 is a motor stand mounted in an anechoic acoustic chamber 1, with a drive (brake) balancing asynchronous (or direct current) machine 3 mounted on a stand-alone foundation 5 vibration-proofed by special springs 4 and mounted below the floor surface 2. The inner concrete shell 6 of the chamber 1 is installed around the perimeter of the floor 7 on special springs 8, and is completely isolated from the outer concrete shell 9 (the principle of construction is “chamber in the chamber”). The floor 10 of the acoustic chamber 1 is vibration-insulated from the foundation 5, on which a balancing asynchronous machine 3 is installed, with rubber seals 11. The surface of the floor 10, 2, walls 6 and ceiling 12 of the chamber 1 is covered with special sound-absorbing wedges (wings) 13. Balancing asynchronous machine 3 through elements mechanical connections transmits torque (brake) moment through the lower shaft 14 installed in the housing 15 of the lower support bearing assembly, the drive belt 16, the upper shaft 17, closed by a protective casing 18. The rotation area of the drive belt 16 is closed by a protective casing 19. The test object - ICE 20 is mounted through elastic rubber mounts 21 and reinforced brackets 22 on vertical struts 23 that can be moved along the transverse rails 24 and fixed in the required position. The transverse guides 24, in turn, can move freely during installation, and

to be fixed along the longitudinal guides 25. The longitudinal guide beams 25 of the ICE mounting device on the stand, racks 26 of the protective casing 18, the housing 27 of the upper support bearing assembly are mounted on the supporting power frame 28. The floor of the test chamber 1 is a soundproof grilles 29 mounted on the supporting support racks and isolated from the frame 30 of the supporting power frame 28. The air cavity of the chamber 1 is ventilated by a high-performance supply 31 and exhaust 32 ventilation. The engine case and its auxiliary mounted units are enclosed by a soundproof casing 33 having a mating hole 34 into which an air intake pipe 35 of the air cleaner is brought out.

The essence of the utility model is illustrated graphically.

Figure 2 presents a fragment of the design of the inventive acoustic motor stand containing a soundproof casing (hereinafter - the casing) 33, covering the ICE body and its auxiliary mounted units. In the proposed embodiment, the casing 33 is mounted on one side of the internal combustion engine (from the location of the intake pipe of the air purifier of the intake system) on the uprights 23 of the ICE mounting device on the stand by fixing the mounting bracket 36 of the casing 33 with the standard tightening bolt 37 of the vertical rack 23. On the opposite side of the internal combustion engine 33 is mounted on a separate rack 38 containing a mounting pin 39, on which the end part of the casing 33 is mounted and fixed with nuts 40. The rack 38 (see figure 3) is made in the form of a metal pipe with an internal thread in its lower part and is installed on the grating of the translucent floor 29 by screwing the mounting bolt 41 into the lower cavity of the tubular stand and pressing it to the grating of the floor 29. To reduce the transmission of vibrational excitation to the casing 33, the tube 38 is mounted to floor through an elastic (eg, rubber) anti-vibration pad 42. If necessary, it is possible to fasten the casing 33 to the engine body through more effective anti-vibration elements (not shown in the sketches) and the use of a combined casing fastening combining mounting options for vertical struts 23, transverse guide beams 24, to the engine body. Bearing plastic metal shell 43 of the casing 33 is made of thin-walled solid or perforated sheet (see Fig. 4, 5 - for example, aluminum, copper, lead, etc.), covering, as a shielding soundproof casing, "extraneous sound-emitting

surface ”of the vibrating walls of the engine body and mounted units. Perhaps the design of the supporting shell 43 in the form of a metal mesh (see Fig.6) of plastic wire (copper, aluminum, steel). The outer surface of the carrier shell 43 (facing the location of the measuring microphone 44) is lined with porous sound-absorbing material 45 (for example, open-cell foam, fibrous porous sound-absorbing mat made of glass, basalt or other types of fibers), providing a weakening of the reflection effect of sound waves generated directly by the investigated source sound (free cut of the intake pipe of the engine intake system), i.e. contributing to the formation of a unified sound field of waves directly emitted by the investigated point emitter (a free cut of the intake pipe) into the spherical space of the propagation medium — the air medium of the measuring room of the anechoic chamber. The outer surface of the porous sound-absorbing material 45 may be lined with a protective sound-transparent layer 46 (for example, a thin apuminized film, maliflise, etc.). The implementation of the carrier shell 43 perforated, in some cases allows you to increase the effect of suppressing noise levels emitted by "extraneous sources" - ICE body, mounted ICE units by improving the absorption conditions of the sound energy generated by them, by the external porous lining of the screen of the bearing shell. Also, the implementation of the structure of the supporting shell in the form of a perforated structure - allows you to avoid converting it into a noticeable secondary emitter of sound in cases of intense vibrational excitation (due, for example, insufficiently effective vibration isolation of support connections with the vibrational ICE body or stand).

In the structure of the casing 33 (see Fig. 7) there is a hole for interfacing 34 with the air intake pipe 35 of the air cleaner of the ICE intake system, which is tightly and unobtrusively covering it in the zone of passage of the pipe through the structure of the casing due to the use of an elastic (e.g. rubber, foam or fiber) seal 47, which has an acceptable soundproofing effect and a soft elastic structure, with high vibration isolation, eliminating the rigid vibration and noise excitation of the casing. At the same time, a free sound-emitting section of the intake pipe of the air cleaner of the intake system is located outside the space covered by the housing casing

ICE with mounted assemblies, i.e. in an area where a lower noise background from extraneous noise sources (ICE with mounted units) is provided. An external sound-absorbing lining of the casing provides a weaker reflection of sound waves emitted directly by a free cut of the pipe of the air cleaner. Thus, the conditions for ensuring a wider dynamic and frequency range of inlet noise studies are realized. The measuring microphone 44 is installed directly near the sound-emitting free cut of the intake pipe of the air cleaner of the ICE intake system (the distance from the microphone to the cut of the pipe is determined by the specific technological procedure of the researcher).

Practical application of the acoustic motor stand declared as a useful model for research and development work on damping the noise of the internal combustion engine intake system allows to mitigate the negative impact on the processes of objective measurements of the sound radiation of the noise produced by the internal combustion engine intake system by isolating the noise radiation of “extraneous noise sources” at the point (points) of measurements, i.e. to increase the dynamic and frequency range of measurements of the studied acoustic parameters of the ICE intake system (sound radiation of the ICE intake system) and, thus, increase the accuracy and objectivity of the estimates made. In addition, the measuring microphone is protected from the effects of high temperatures if the microphone is located near the thermally loaded parts of the internal combustion engine.

Claims (1)

An acoustic motor stand for research and development work on damping the noise of the intake system of an internal combustion engine, installed in an anechoic chamber with a soundproof floor, containing a load brake, mechanical connection elements of the ICE shaft with the load brake shaft, control and measuring equipment sets, the object of research is ICE with mounted assemblies, mounted on a stand with the help of supporting all-metal longitudinal and transverse guides and all-metal racks, excellent the fact that the ICE case with mounted assemblies is enclosed by a soundproof casing mounted both directly on separate areas of the ICE case, on the supporting elements of the ICE fastening devices on the stand, and on a separate support stand mounted on the supporting elements of the soundproof floor of the anechoic chamber by means of a bolt connection through vibration-isolating gaskets, while the bearing shell of the casing is made in the form of a continuous or perforated thin-walled metal sheet (preferably of easy def of the metal being formed - aluminum, copper, lead), or from a similar material of a metal wire mesh, the outer surface of the bearing shell of the casing is made of porous sound-absorbing material with a protective sound-transparent layer, in addition, a communication communication hole is made in the structure of the casing, with an air intake passing through the structure of the casing ICE intake system air intake pipe, tightly and unobtrusively covering it in the interface zone with the casing with elastic rubber, porous istym or fibrous sealant and provides accommodation free of the sound cut the air intake pipe of an air cleaner is the space covered by the housing body with an internal combustion engine mounted units assembled.