RU23504U1 - ACOUSTIC MOTOR RESEARCH STAND - Google Patents

Description

privately tested inside benches Acoustic motor research bench. The utility model relates to control and diagnostic equipment, awn to a test bench for conducting vibroacoustic bench engines of internal combustion engines (hereinafter ICE). To determine the main technical indicators of its combustion engines (hereinafter referred to as ICE), special test vehicles equipped with various devices and measuring equipment are used. As a 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 ICE and brake under study; racks for installing and fixing ICE on a foundation plate; load brake (hydraulic, electric) to absorb the power developed by the internal combustion engine with a torque measuring device on the motor shaft (brakes); shaft and special couplings for connecting the ICE crankshaft to the brake shaft; devices and communications for supplying to the internal combustion engine a cooled lubricating oil, a cooling liquid of the internal combustion engine cooling system, exhaust into the atmosphere exhaust and crankcase gases of the internal combustion engine; devices and communications for supplying ICE 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 workflow and engine parameters (ignition timing, mixture composition, timing of the start of injection); MPK7 G01M 17/00

a remote control with the ICE start-up and control bodies located on it; instruments for monitoring the operation of internal combustion engines 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 stress, deformation of individual parts, etc.).

Known technical solution for the execution of the stand for running and testing the internal combustion engine (RF patent No. 2107175, according to the application 96114020), containing the base, load (brake) and connecting devices. On the base are fixed longitudinal guides on which the frame is mounted. made in the form of autonomous beams. Beams are installed with the possibility of movement along the longitudinal guides and fixing relative to them. Transverse guides are fixed on the beams, on which racks are installed with the possibility of moving along them and fixing. The racks are fixed lodgment for placing the internal combustion engine with the ability to move and fix in a selected direction.

The disadvantages of this technical solution are:

rigid transmission of vibrational excitation from the investigated internal combustion engine to the connecting metal elements of the base and connecting devices of the stand (lodges, racks. transverse and longitudinal guides, autonomous frame beams) and, as a result, intense noise radiation from these elements into the space of the test room (motor box);

hard and intense transmission of excitation from a working load (brake) device (electric machine) to the metal elements of the base and the connecting devices of the stand (lodges, racks, transverse and longitudinal guides, autonomous frame beams);

emission of airborne noise into the space of the test room of the motor box directly by the body and fan of the electrical machine of the load device;

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the turn is due to the fact that it is necessary to minimize extraneous (in addition to the ICE being studied) noise emissions from drive mechanisms and systems of bench equipment of the motor box.

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, are widely used.

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

2 GUP NITSIAMT “Acoustic center will perform :. Automotive industry, 2000, No. 11.1.

3 Peter Gutzmer und Reimer Pilgrim. Motorakustische Versuchs-und Mer technik bei Porsche. MTZ, Motortechnische Zeitschrift, 48 (1987), 2, 47 ... 50.

In particular, in 1 there is an example of using a semi-muffled acoustic camera from Chrysler (USA), in 2 - an acoustic motor stand of the GUP NITSIAMT central autopolygon (Dmitrov, Moscow region) with a hard sound-reflecting floor, on the groove plate of which using special stands the studied ICE is fixed. The brake (or drive - in the engine scrolling modes without implementing the workflow in it) bench setup (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 provide transmission of 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, exhaust gas systems 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, the sound emission from the lower part of the ICE).

located in close proximity to the sound-reflecting surface of the floor, which, as a rule, is the most noise-vibrational for all piston ICEs). It is in connection with this that the lower ICE 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 cardan shafts with thrust bearings installed in vertical racks mounted on a slot plate and directly on the chamber floor as connecting drive elements connecting the ICE crankshaft and the brake stand power take-off shaft causes problems of their alignment with the crankshaft of the test ICE, and, as a consequence, the generation of vibrosilicon at frequencies and ordinal harmonics of their rotation, transmitted via reference links as directly to the ICE under study, causing it to complement noise emission, as well as to some attached 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 by the protective casings of the test shafts, as well as the emission of“ spurious sound directly by the acoustic floor the camera, due to the transmission of this vibrational excitation to the floor (groove plate) through the supporting racks of the shafts.

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 3, used in the research center of Porsche (Germany). In this case, it involves 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 ICE case, as an object of study, in this case is located near the geometric center of the airspace of the chamber, i.e. in the most

remote from reflective 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. Thus, this design 3 of the acoustic motor stand is more advanced and is adopted as a prototype.

One of the intense noise emitters is the housing of the upper support bearing assembly of the acoustic motor stand 3, which is a massive metal base, which is closed on top by a removable thin-walled metal cover. A significant drawback of the known housing design of the upper support bearing assembly is the high vibroacoustic excitability of the housing structure at the resonant frequencies of the bending vibrations of its walls, as well as the weak soundproof ability of the thin-walled metal structure of the cover walls from excitation and transmission of airborne noise generated in the air cavity of the housing under the cover, which leads to to additional noise radiation into the space of the anechoic acoustic chamber during acoustic tests of the ICE under study, and, thus, to reduce the accuracy of measurements of noise emitted by the test object, and the reliability of research acoustic work. Noise from the noisy area of the engine room (for example, noise from an asynchronous balancing machine, fans, pumps) through the connecting channel of the drive belt casing easily penetrates into the interior of the housing of the upper support bearing assembly, excites metal walls of the housing cover by air, and, ultimately, is re-emitted into the test chamber room in the form of a parasitic noise signal, thereby distorting the real sound field around the ICE under study. Rotating drive elements of the stand (shaft, thrust bearings, belt) are additional sources of noise in the space of the housing of the bearing bearing assembly, generating the corresponding sound waves also transmitted into the space of the anechoic chamber with high vibrational excitability of the base and cover and the weak soundproof ability of the walls of the cover of the upper support housing bearing assembly. In addition, the metal walls of both the lid and the base are excited in a rigid way, transmitted from the vibrating drive elements of the stand, while emitting the corresponding spurious

structural noise in the ICE research area, with installed measuring microphones, adversely affecting the state of the free sound field around the test object. A drawback of the housing design of the upper support bearing assembly is also the large sound reflection area of the external hard surface of the housing, which leads to the appearance of additional sound reflecting effects that distort the real (free) sound field around the object under investigation (ICE).

The proposed solution allows to eliminate the above disadvantages.

The essence of the utility model lies in the fact that in the well-known acoustic motor research stand, which contains, in particular, a supporting frame of the power frame, on which is mounted the metal housing of the upper support bearing assembly, which is closed on all sides by an acoustic capsule “floating (not rigidly fixed to the supporting surface) ) type, which is a soundproof sound-absorbing casing mounted on an elastic rubber substrate, while the frame of the acoustic capsule is made of thin-walled a metal sheet damped from the outside and inside with a layer of vibration damping material (for example, a self-adhesive or thermofusible bitumen laminate) lined on both sides with sound-absorbing panels of porous (fibrous or open-cell foam) material lined with an external protective soundproof transparent capsule layer in front of the carcass, two removable, rigidly fixed covers having an opening to cover the protective casing of the drive shaft, mating with the housing the upper bearing assembly, while the walls of the capsule shells of the acoustic capsule are damped from the outside and inside with a layer of vibration-damping material and lined with sound-absorbing panels lined with an external protective sound-transparent layer, the capsule has four handles for easy movement, while the handles are removable.

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

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In FIG. 1 shows a muffled anechoic acoustic chamber in which an acoustic motor research stand claimed to be a utility model is installed.

In FIG. 2, 3, a fragment of the construction of the proposed acoustic motor research stand is presented, comprising a supporting frame, with a housing of a support bearing assembly mounted thereon and closed by a floating-type acoustic capsule.

The utility model shown in FIG. 1, is an acoustic motor research stand mounted in an anechoic chamber 1, with a drive (brake) balancing asynchronous (or direct current) machine 3 mounted on a stand-alone foundation vibro-insulated with special springs 4 and mounted below the floor surface 2. An inner concrete shell 6 of chamber 1 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 chamber”). The floor 10 of the acoustic chamber 1 is vibration-insulated with rubber seals 11 in the zones of interface with the adjacent surfaces of the foundation 5, on which a balancing asynchronous machine 3 is installed. The surfaces of the floor 10, 2, walls 6 and ceiling 12 of the chamber 1 are covered with special sound-absorbing wedges (wings) 13. Balanced asynchronous the machine 3 is fixed to the foundation floor 5 and transmits torque (braking) 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 skin ear 18. The rotation area of the drive belt 16 is closed by a protective casing 19. The test object - ICE 20 is mounted on vertical struts 21 of the ICE fastening system on the stand through special rubber-metal elastic supports 22. Longitudinal beams 23 of the ICE fastening system, the base 24 of the upper bearing assembly are mounted on the supporting power frame 25. The inner floor of the test chamber 1 is a soundproof lattice 26 vibroisolated from the supporting frame 27 of the power frame 25. The air chamber of the acoustic chamber Camera 1 is ventilated high-performance exhaust plenum 28 and 29 ventilation.

The essence of the utility model is illustrated graphically.

27, on which the massive metal base 24 of the upper support bearing assembly body 24, which is closed on top by a metal cover 30, is rigidly fixed. The housing of the upper support bearing assembly is closed by a floating-type acoustic capsule 31 mounted on an elastic rubber substrate 32. The capsule 31 is made in the form of a thin-walled metal frame 33, which is closed in front by removable metal covers - upper 34 and lower 35, which are rigidly fixed by means of fixing screws 36. To weaken the excitation of structures vibrations and sound, and additional sound insulation, the walls of the frame 33 and the covers 34, 35 from the outside and the inside are damped with a layer of vibration damping material 37 (for example, a self-adhesive or hot-melt bitumen laminate). For significant absorption of additional sound waves generated by the drive elements of the stand and operating equipment in the engine room, the walls of the capsule 31 (frame 33, covers 34, 35) are lined on both sides with effective sound-absorbing panels 38 of porous (fibrous or open-cell foam) lined with in turn, with an external protective soundproof layer 39 (for example, soundproof, non-combustible, moisture resistant, fiberglass cloth or a thin, protective, heat-resistant, moisture and gas impermeable translucent foil). In addition, the lining of the outer surface of the capsule 31 with sound-absorbing panels 38, allows, first of all, to provide a weakening effect of the sound reflection of waves generated by the object of study two and incident on the surface of the capsule 31 from the free space of the acoustic anechoic chamber 1, i.e. to reduce the distortion of the field of sound waves emitted directly by the object of research - ICE 20. The upper 34 and lower 35 capsule caps 31 tightly (without gap) cover the protective casing 18 of the drive shaft 17 and the bracket 40 of the protective casing 18, thereby reducing the transmission of sound waves into the zone measurements of the acoustic anechoic chamber from the side of the end part of the cavity of the casing 18. For the convenience of moving the capsule 31 (for example, if necessary, access to the drive elements of the upper support bearing assembly during maintenance zhivaniya) provided the handle 41. Handles 41 - removable type, to enable their disassembly in order to improve the aesthetic appearance of the capsule.

Practical implementation of the proposed design of an acoustic motor research stand will improve the accuracy and objectivity of the results of bench vibroacoustic tests of internal combustion engines.

Claims (1)

An acoustic motor research stand mounted in a muffled anechoic acoustic chamber, comprising, in particular, a support frame mounted vibro-insulated from the floor of the acoustic chamber, on which a massive metal base of the housing of the upper support bearing assembly kinematically connected to the drive shaft of the balancing machine and the drive shaft of the engine under study is fixed combustion method, characterized in that the housing of the upper support bearing assembly with a clearance is surrounded by an acoustic chamber a floating-type psula installed on an elastic rubber substrate, the capsule is made in the form of a thin-walled metal frame, closed by vertical removable metal covers that are rigidly fixed by means of fasteners, the frame walls and covers from the outside and inside are damped with a layer of vibration-damping material, the capsule wall from two the sides are lined with effective sound-absorbing panels of porous (fibrous or open-cell foam) material, the outer surfaces of which of sound transmission are lined with a protective layer.