RU33226U1 - A device for directional blowing of thermally loaded units of a power plant and / or wheeled vehicle during their bench acoustic tests - Google Patents

Description

2003114695

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DEVICE FOR DIRECTED BLOWING OF THERMO-LOADED UNITS

ENERGY INSTALLATION AND / OR WHEELED VEHICLE IN THE PROCESS OF THEIR POSITION ACOUSTIC TESTS.

The utility model relates to the field of research of vibro-acoustic processes of wheeled vehicles.

Solving the problem of reducing acoustic pollution of the environment and improving the acoustic comfort of power plants and 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 refinement processes, in particular, vehicles for 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 road (field) driving conditions (for example, dynamic stands with running drums), stationary measuring and analyzing equipment. Constant weather conditions 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. Due to the fact that the main vibro-noise source of a vehicle is its power plant - an engine with transmission units (hereinafter the power unit), it is also very important to conduct research and refinement of the power unit on the stand when simulating various speed and infusional modes (by changing the engine speed, angle of opening) throttle, etc.).

A fairly complete imitation of the car’s driving conditions in real road conditions can be achieved on stands with running drums, the practice of which has been widely used at enterprises producing motor vehicles and research institutes.

 III PI II

Modern technologies for the study of acoustic processes that are implemented on vehicles (cars, tractors, motorcycles, etc. types of wheeled vehicles) include, in particular, the use of special low-noise running drums that allow you to simulate various speed and load modes of operation of energy and transmission units of vehicles in conditions for their placement in special anechoic or semi-anechoic acoustic chambers that contribute to the formation of free sound New field in the measurement zones.

An anechoic or semi-anechoic (sonic, drowned out) test chamber is a room installed on a separate foundation, vibration-insulated from the main building. In such a chamber, a stand with running drums (or a motor brake stand) is placed, vibration-insulated 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, in a special engine room. To approximate the acoustic properties of the camera to a free sound field, directional coordination of the acoustic impedances (resistances) of the air environment and sound-absorbing material lining the sound-reflecting surfaces of the walls, ceiling, and the floor is necessary. Therefore, the design of the sound-absorbing cladding of the walls (floor, ceiling) of the chamber must be made porous and have a structural density (porosity) that gradually changes in depth of the coating in the direction of propagation of sound waves to the rigid sound-reflecting surface of the walls (floor, ceiling). Moreover, the highest density is realized directly at the walls of the chamber, and the lowest - 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 air in the zones of the walls and ceiling are achieved, in particular, by using various wedge-shaped volumetric absorbers (wedges, backstage). The main materials from which sound-absorbing wedges are made are open-cell polyurethane foam, fiberglass, mineral wool, superthin basalt fiber, vinipore with fire-resistant impregnation.

chamber, or an internal combustion engine (hereinafter referred to as ICE) mounted on a brake stand in an anechoic acoustic chamber, there is a need for air-blowing of thermally loaded units of a power plant and / or wheeled vehicle. Blowing the front of the vehicle is necessary in order to cool the radiator of the internal combustion engine cooling system to ensure the normal functioning of the internal combustion engine cooling of the vehicle and the possibility of testing under high load conditions. In addition, an increase in temperature infusions on body elements, rubber vibration isolators, parts made of polymer materials, leads to a change in the vibro-acoustic characteristics of these materials used in the transport federation and, as a result, to an unpredictable decrease in the objectivity and reliability of the results of acoustic measurements. To cool the thermally loaded vehicle afegates (ICE body, oil pan, exhaust manifold, exhaust system, clutch transmission units, gearboxes, drive axles, etc.), a special directional blower (fan blower) is used, which is characterized by low noise level, installed in the space of the test acoustic chamber, in the immediate vicinity of the measuring microphones, as a rule, in front of the test one on the run drums of the vehicle, or in the immediate vicinity of the ICE body (exhaust manifold, oil pan) of the power plant under study installed in an acoustic motor box. The location of the fan blower near the studied objects (wheeled vehicle and / or ICE) is necessary to ensure full blowing and effective cooling of thermofused units. In addition, the removal of the fan blower from the object of screeching at a sufficient distance is not possible due to the limited space of small-sized acoustic test chambers. The use of axial fans is quite justified as a directional blower device. As a rule, these are fans with an individual direct electric drive, with an impeller mounted directly on the motor shaft. The fan casing has a calibrated inner diameter and increased rigidity. The calibrated inner diameter of the casing allows

minimize the gap between the outer diameter of the impeller and the casing, and, therefore, reduce air loss in the fan and reduce the generation of sound by the peripheral zones of the fan blades. The increased stiffness of the casing reduces the overall noise level emitted directly by the vibrating fan casing. In addition, in order to minimize vibration and noise, impeller balancing is mandatory, which is performed directly on the shaft of its own electric motor, which reduces the dynamic (vibrational) excitation of the fan casing and, accordingly, reduces the level of case noise generated by it.

In addition to the use in semi-anechoic acoustic chambers with a dynamic drum stand, the directional blower is also used in anechoic chambers for burning ICE in an acoustic motor stand. In this case, there is a need for cooling thermally infused parts and assemblies of the internal combustion engine under study, in particular, the collector (the temperature of the collector at maximum refueling reaches 1000 ° C), the exhaust pipe, exhaust hose, oil pan.

Known dynamic stand with running drums acoustic center company FEV, the design of which is presented in the publication Engine Technology International, 01.2002, p. 44 ... 45. The stand is located in a semi-anechoic acoustic chamber. The walls and ceiling of the chamber around the perimeter are lined with special sound-absorbing wedges that contribute to the formation of a free sound FIELD in the measuring zone. At high speed and load modes of operation of the internal combustion engine, there is a need to cool the test vehicle with a directional blower.

A well-known stand for acoustic testing of internal combustion engines in an anechoic acoustic chamber of the research center f. Porsche (Germany), presented in the publication Peter Gutzmer und Reimer Pilgrim. Motorakustische Versuchs-und Meptechnik bei Porsche. MTZ, Motortechnische Zeitschrift, 48 (1987), 2, 47 ... 50. The brake (load) stand is installed in the center of the chamber below the floor surface of a completely muffled anechoic acoustic chamber. The transmission of torque (braking) is thus endless

flexible connection - smooth transmission. 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 (floor) is covered with an effective noise-absorbing material (special

sound-absorbing wedges). The engine housing, as an object of study, is located near the geometric center of the airspace of the chamber, i.e. in the zone farthest from the sound-reflecting surfaces of the walls, floor, ceiling (with the best acoustics). In this case, it is necessary to periodically use the device of directional blowing during the internal combustion engine testing, cooling the thermally infused parts and the internal combustion engine components and providing the optimum temperature regime.

A well-known dynamic stand with running drums of the acoustic center of the central avtopolygon GUP NITSIAMT (Dmitrov, Moscow region), located in a semi-anechoic chamber, the design of which is presented in the publication Acoustic Center will perform :. Automotive industry, 2000, No. 11, 1. As shown in the photo, in front of the vehicle mounted on the running reels of the dynamic stand, there is a directional blower in the form of an axial fan blower with a massive, large surface area, cylindrical metal casing.

Known dynamic drum stand for acoustic research vehicles acoustic center f. AVL (Austria), the design of which is described in detail in the published report SAE 971900 Design, Construction and Application of a World Class Venicle Acoustic Test Facility, F.K. Brandl, p. 241-247. The stand is located in a semi-anechoic funeral chamber. The chamber is a closed concrete rectangular shell with a wall thickness of 30 cm. The concrete shell is located on vibration isolators, whose natural frequency is 2.5 Hz. The walls and ceiling of the semi-anechoic chamber are lined with sound-absorbing fiberglass-based wedges. The length of the wedges is 1 m. In the corners of the chamber there are nozzles of supply and exhaust ventilation, the capacity of which is 40,000. The level of intrinsic noise in the chamber with the supply and exhaust ventilation turned on is 47 dBA. Blowing the front end of the vehicle examined at the drum stand is carried out by a powerful ventilation unit (see

FIG. 11), the nozzle of which is located in the space of the test chamber immediately in front of the test vehicle.

A well-known stand for acoustic testing of vehicles, the design of which is presented in the patent of Germany No. PS 3715016, MKI4 G01M 17/00, publ. 12/01/88, accepted as a PROTOTYPE. The test bench is located in a semi-anechoic acoustic chamber with wall and ceiling cladding with sound-absorbing wedges that contribute to the formation of a free sound FIELD. The vehicle is blown during acoustic tests by a special fan blower, the nozzle of which is a continuation of a special elastic channel and is located directly in the test chamber in front of the vehicle under study installed on the test bench. The nozzle body is made in the form of a cone-shaped parallelepiped with rigid overall surfaces.

The disadvantage of the above, known acoustic stands for researching wheeled vehicles and their power plants, two, located in semi-anechoic or anechoic acoustic chambers, is the influence of a sound-reflecting body with a large reflection area of sound from directional blowing devices, the need for which is due to the technology of the tests, on the free sound field in areas where measuring microphones are located. Sound waves emitted by the investigated vehicle (or the ICE under study) are additionally reflected in this case from the hard metal surfaces of the casings and the rack frame of the directional blower device, falling into the space of the measuring zone around the test object under study, with measuring microphones installed in it, which is directly has a negative impact on the accuracy and objectivity of research and development work.

The proposed technical solution can significantly eliminate the above disadvantages.

tests, the main elements of which are an electric motor, an impeller, a casing, a guiding element and a mobile stand, form a free sound field by attenuating the reflected sound field in the measurement zone of sound energy emitted by the vehicle under test during bench tests, by lining the outer surfaces of the casing, guide element and carcass of the mobile stand with self-adhesive sound-absorbing porous fibrous or open-cell foam material with external protective m soundproof layer.

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

In FIG. Figure 1 shows a semi-anechoic test chamber with a test vehicle mounted on the running drums of a dynamic test bench and installed in front of the vehicle near the vehicle with a device for directed blowing of thermo-inflated units of a power plant and / or wheeled vehicle during their bench acoustic tests, forming a free sound field by attenuating the reflected sound field in the measurement zone of sound energy emitted by a vehicle, used as a utility model. With reference to FIG. 1 marked:

1- semi-anechoic test chamber;

2- sound-absorbing backstage;

3- test vehicle;

4-measuring microphones;

5- directional blower device.

In FIG. Figure 2 shows an anechoic test chamber with the ICE under study installed on it on the acoustic motor stand, and installed opposite the ICE device for directed blowing of thermally loaded units of the power plant and / or wheeled vehicle during their bench acoustic tests, forming a free sound field by attenuating the reflected sound field in the measurement zone of sound energy emitted by a vehicle, claimed as a utility model. With reference to FIG. 2 are indicated;

4-measuring microphones;

5 - directional blower device;

6 - anechoic test chamber;

7 - examined ICE;

8- front pipe;

9- metallized hose of the exhaust system of the exhaust system.

In FIG. Figures 3 and 4 show the design of a device for directional blowing of thermally loaded units of a power plant and / or wheeled vehicle during their acoustic bench tests, which forms a free sound field by attenuating the reflected sound field in the measurement area of sound energy emitted by the vehicle.

The casing of the directional blowing device (fan blower) 10 is made, as a rule, of sheet steel or other metal material in the form of a cylinder with flanged flanges and two brackets 11 welded inside to fix the bearings 12 of the electric motor 13 on them. The impeller is mounted directly on the electric motor shaft 13 14. The impeller consists of several aerodynamically shaped aluminum blades, with the possibility of installing the blades at any angle in a given regulation range, in order to reach and the necessary parameters for pressure, performance and power consumption. The impeller is balanced statically in dynamic mode when it is mounted directly on the shaft of its electric motor. To the end face of the casing, on the outlet side of the air stream, a guide element 16 is fastened with a screw connection 15 in the form of a truncated cone made of a metal sheet or of a polymeric material. The casing of the fan blower is mounted on a movable stand 17 using a swivel joint 18, which allows you to set the required angle to the guide element 16, and, accordingly, to orient the direction of the flow of blown air. The stand 17 has wheels 19 with a massive rubberized surface to reduce the transmission of vibrational energy to the floor of the test chamber. The outer surfaces of the metal structure 20 of the casing 10, the frame 21 of the rack 17, the metal (polymer) structure 22

the guide element 16 around their perimeter is lined with sound-absorbing porous, fibrous or open-cellular foam material 23, lined with, in turn, a protective sound-transparent layer 24. The protective sound-transparent layer 24 is made primarily of washable, fire-resistant, moisture-oil-gas-resistant material that does not allow the specified substances inside the porous structure of a sound-absorbing material that can be easily cleaned with a vacuum cleaner or wet cleaning. The lining of the external surfaces of the directional blowing device with sound-absorbing material makes it possible to attenuate the sound reflection effect of waves generated by the object of research (a means of transport or ICE) and incident on the surface of the casing 10, the guide element 16 and the stand 17 from the free space of the acoustic anechoic (semi-anechoic) chamber, and Thus, to reduce the distortion of the field of sound waves emitted directly by the object of study - a vehicle or ICE, in the installation areas ritelnyh microphones.

The practical implementation of the directional blowing device, claimed as a utility model, allows one to minimize the influence of the reflected field in the measurement zone of the sound energy emitted by the vehicle or ICE being tested during bench tests resulting from the test chamber located in the vicinity of the test object, the directional blowing device, and to increase, thus, the accuracy and objectivity of the results of bench vibration-acoustic tests of the vehicle (ICE).

Claims (1)

A device for directed blowing of thermally loaded units of a power plant and / or wheeled vehicle during their acoustic bench tests, comprising, in particular, an electric motor, an impeller, a casing, a guiding element and a mobile stand, characterized in that the outer surfaces of the casing, the guiding element and the frame mobile racks are faced with self-adhesive sound-absorbing porous fibrous or open-cell foam material with an external protective sound-transparent layer.