RU53010U1 - MOTOR STAND FOR VIBROACOUSTIC TESTS OF INTERNAL COMBUSTION ENGINES - Google Patents

Abstract

The utility model relates to control and diagnostic equipment, in particular, to a motor test bench for conducting vibroacoustic tests of internal combustion engines (hereinafter - ICE). The bench includes, in particular, an anechoic acoustic chamber, an ICE mounting system on the bench with the ICE under study mounted on the bench, bench drive elements kinematically connecting the ICE crankshaft to the drive shaft of the brake balancing asynchronous machine of the stand. A distinctive feature is that the motor stand contains a laser device for centering the axes of the mating shafts (the drive shaft of the brake balancing asynchronous machine and the crankshaft of the ICE under study), made in the form of a single module containing a base and a cylindrical body with a laser diode rigidly mounted in it, while , the base contains a permanent magnet in the form of a “magnetic suction cup” and is mounted on a mounting pad made of ferromagnetic material, the plane of which is perpendicular to the bp axis scheniya drive shaft brake equalizer of the asynchronous machine, and the luminous beam of the laser beam is directed to the center (rotation axis) of the end portion of said drive shaft; the surface of the mounting pad contains a calibration mark for periodically calibrating the alignment coordinates of the laser alignment device module. Design options for the stand are proposed. The practical implementation of the proposed motor stand for vibro-acoustic testing of internal combustion engines allowed to ultimately increase the accuracy and objectivity of the results of bench vibro-acoustic research of internal combustion engines.

Description

The utility model relates to control and diagnostic equipment, in particular, to a motor test bench for conducting vibroacoustic tests of internal combustion engines (hereinafter - ICE).

It is known that to determine the main technical parameters of the internal combustion engine and conduct research and development work, specialized motor test benches are used, equipped with various auxiliary devices and measuring equipment.

As a basic equipment, a motor bench for ICE testing contains:

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

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

- 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 internal combustion engine shaft (brakes);

- a 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, coolant for 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;

- devices for regulating and determining individual parameters affecting the working process and the internal combustion engine parameters (ignition timing, mixture composition, timing of the start of injection);

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

- a remote control with the start-up and control bodies of the internal combustion engine located on it;

- devices for monitoring the operation of the internal combustion engine and devices for recording the operating parameters of the internal combustion engine;

- devices and devices intended for special studies to determine the individual physical parameters of internal combustion engines (toxicity, smoke, noise, vibration, thermal stress, mechanical deformation of individual parts, etc.).

It is known, in particular, the technical solution for the execution of the bench for running in 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 a frame is made, made in the form of autonomous beams. Beams are installed with the possibility of movement along the longitudinal rails 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 placement of ICE 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 spurious noise radiation from these elements into the space of the test room (motor box) ;

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

guides, autonomous frame beams) followed by spurious noise radiation into the airspace of the measuring chamber;

- emission of spurious airborne noise into the space of the test room of the motor box directly by the casing and the impeller of the fan of the electric machine of the loading device;

- radiation of spurious structural and airborne noise by vibrating elements of the connecting drive shaft and enclosing casing installed between the ICE under study and the brake assembly;

- a large reflective surface of the enclosing protective casing of the drive connecting shaft, distorting the conditions of the free sound field at the measuring points around the ICE under study.

Due to the listed technical shortcomings, this type of stand concept did not find application in the practice of modern vibroacoustic tests of ICEs, primarily due to the fact that in this case it is not possible to minimize extraneous spurious (in addition to the ICE under study) noise emissions from drive mechanisms and bench equipment systems of such a 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 have been used [for example, 1, 2, 3]:

[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 Gutzmer und Reimer Pilgrim. Motorakustische Versuchs-und Me β technik 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 avtopolygon 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. Brake (or drive - on

modes of scrolling the internal combustion engine without implementing the workflow in it) the stand settings (there are 2 of them) are 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 drive shafts (power take-off shafts), which transmit torque or braking torque between them. The end sections of the drive shafts are fixed with 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 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, distorting the real sound field of the ICE under study (in particular, sound emission from the lower part of the ICE (crankcase, oil pan) located in close proximity to the sound-reflecting floor surface, which, as a rule, for all piston ICEs it is the most noise-vibrational). It is in connection with this that the ICE lower zone is of greatest practical interest to researchers and closers of ICE, as a rule, and requires the most time-consuming and, if possible, the most accurate and objective studies. On the other hand, the use of long propeller shafts with thrust bearings installed in vertical racks mounted on a slot plate and directly on the chamber floor as rotary drive elements connecting the ICE crankshaft and the power take-off of the stand brake machine, causes problems of their alignment with the crankshaft of the test ICE, and, as a consequence, determines the generation of vibro-forces at the frequencies and ordinal harmonics of their rotation, transmitted via reference links as directly to the ICE under investigation, causing it about additional spurious noise emission, as well as to some attached structures of the acoustic chamber (for example, the chamber floor), 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 radiation of “spurious” sound directly excited by the floor structure of the acoustic chamber, due to the transmission of this vibrational excitation to the floor (groove plate) through the shaft support legs.

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] - PROTOTYPE 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 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 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], and 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 accepted as a prototype. The disadvantages of the known prototype of an acoustic motor stand with a belt drive [3], as well as the above designs of motor stands, is the unresolved problem of high-precision alignment of the crankshaft of the ICE under study with the mating drive shaft of the brake balancing asynchronous machine for the subsequent elimination of possible intense dynamic (vibration) excitation of the mechanical devices of the stand and the internal combustion engine under investigation, caused by the misalignment of the rotation axes of these shafts. The alignment of these mating shafts is often carried out using indirect low-current alignment methods (for example, a method that uses the principle of divergence (convergence) of two centering arrows mounted on the flanges of the centering shafts). These centering methods differ not only in low accuracy, but also in poor performance. The lack of a reliable and high-precision method of aligning the shafts during the installation of ICEs on the bench leads to the generation of additional vibratory forces at the main exciting frequencies and the harmonics of their rotation transmitted through the shaft support connections to the attached solid structures of the bench and acoustic chamber, which leads to

the occurrence of “spurious" vibrational excitation and noise, which impedes a qualitative objective study of the vibrational and noise characteristics of ICE mounted on a motor stand.

The technical result of the claimed utility model consists in equipping a motor stand for vibroacoustic testing of ICE with a laser device for centering the axes of the drive shaft of the brake balancing asynchronous machine and the crankshaft of the ICE during the installation of the ICE on the stand.

The specified technical result in the implementation of the claimed utility model is achieved by the fact that in the well-known motor stand for vibroacoustic testing of internal combustion engines, containing, in particular, an anechoic acoustic chamber, an internal combustion engine mounting system on the stand with the studied internal combustion engine mounted on the stand, drive elements of the stand kinematically connecting the crankshaft ICE with the drive shaft of the brake balancing asynchronous machine of the stand - contains a laser device for centering the axes of the mating shafts - the drive shaft of the brake balancing an asynchronous machine and the crankshaft of the ICE under study, made in the form of a single module containing a base and a cylindrical body with a laser diode, while the base contains a permanent magnet in the form of a “magnetic suction cup” and is mounted on a mounting pad of ferromagnetic substance, the plane of which is perpendicular to the axis of rotation drive shaft brake balancing asynchronous machine. The luminous beam of the laser beam is directed to the center (axis of rotation) of the end (end) section of the specified drive shaft. The mounting pad contains a calibration mark for periodic calibration alignment of the location coordinates of the laser centering device module. For the location of the rotation axis of the crankshaft of the ICE under investigation perpendicularly (opposite) to the surface of the entrance door of the test chamber, the surface of the entrance door can be used as an installation site for installing the laser centering device module. In this case, it means a sheet steel door or a plate containing a ferromagnetic substance. If the axis of rotation of the ICE crankshaft is opposite the blank wall of the test chamber, the mounting pad of ferromagnetic material is mounted on this wall. After the centering operations of the mating shafts, the blind wall section of the anechoic acoustic chamber is closed by a removable sound absorber such as the sound-absorbing lining (wedges, wings) of the acoustic anechoic chamber surface.

Comparison of published in the open press of scientific and technical and

Patent documentation on the priority date in the main and related sections of the MKI shows that the set of essential features of the claimed decision was not previously known, therefore, it meets the patentability condition of "novelty."

The proposed technical solution is industrially applicable, because can be manufactured industrially, efficiently, feasibly and reproducibly, therefore, meets the patentability condition “industrial applicability”.

The utility model is illustrated by drawings, where

Figure 1, 2 shows a motor stand claimed as a utility model for vibroacoustic testing of ICE mounted in an acoustic anechoic chamber and equipped with a laser device for centering the axles of the crankshaft of the ICE under study with a drive shaft of the brake balancing asynchronous machine of the stand.

Figure 3 presents a diagram of the mechanical drive of the motor stand for vibroacoustic testing of the internal combustion engine, kinematically connecting the crankshaft of the internal combustion engine under investigation with the drive shaft of the brake balancing asynchronous machine of the stand.

Figures 4, 5, 6 are diagrams illustrating the sequence of operations of centering the axles of the crankshaft of the ICE under study with the drive shaft of the brake balancing asynchronous machine of the stand, using a laser centering device used as a standard component of the motor stand.

7 shows an embodiment of a mounting pad of a laser centering device mounted on a wall surface of an anechoic acoustic chamber.

The utility model, according to the scheme of Fig. 1, is a research motor stand, which includes a completely damped anechoic acoustic chamber 1, with a drive (brake) balancing asynchronous (or direct current) machine 3 mounted on a vibration-insulated bottom below the surface of the floor 2 springs 4 of an autonomous foundation 5. The inner concrete shell 6 of the chamber 1 is installed around the perimeter of the floor 7 on the springs 8, and is completely isolated from the outer concrete shell 9 (the principle of construction is “chamber in amer "). 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. Surfaces

the floor 10, walls 6 and ceiling 12 of the chamber 1 are covered with sound-absorbing wedges (or wings) 13. The chamber 1 contains at least one entrance door 14 of steel sheet or another type of material with a local area made of ferromagnetic material. In the process of testing the internal combustion engine, the door closes, and the doorway from the camera side is pushed by a mobile sound-absorbing trolley 15 (see figure 2). The balancing asynchronous machine 3 transmits torque (braking) moment through the lower shaft 16 installed in the housing 17 of the lower support bearing assembly, the drive belt 18, the drive shaft 19, which is closed by a soundproofing shroud 20 (when aligning the shafts during the installation of the internal combustion engine, the soundproofing shroud is removed). The rotation zone of the drive belt 18 is closed by a protective casing 21. The test object - ICE 22 is mounted on vertical adjustment racks 23 of the ICE fastening system on the bench, containing a set of adjusting washers for purposefully changing the spatial position of the ICE mounted on the bench during alignment operations of the mating shafts. The longitudinal beams 24 of the internal combustion engine mounting system, the housing 25 of the upper support bearing assembly are mounted on a supporting power frame 26. The floor of the test chamber 1 is a soundproof grilles 27 vibro-insulated from the frame 28 of the supporting power frame 26. The air chamber of the chamber 1 is ventilated by a high-performance supply 29 and exhaust 30 ventilation. During the installation of the internal combustion engine on the bench for high-precision alignment of the internal combustion engine crankshaft with the drive shaft 19 and the shaft 31 of the upper support bearing assembly of the drive of the brake balancing asynchronous machine 3, a laser alignment device 32 is used in the form of a single module mounted on the surface of the front door 14.

Figure 3 presents a diagram of the mechanical drive of the motor stand for vibro-acoustic testing of the internal combustion engine, explaining the dynamics of the occurrence of structural vibrations and radiation of spurious noise by vibro-loaded rotating drive elements, their bodies, structures attached to them in case of unsatisfactory "tuning" of various parts of the mechanical drive of the brake balancing asynchronous machine , including insufficiently accurate alignment of the ICE crankshaft with the shafts of the specified drive.

The positions in figure 3 are indicated:

18 - a driving belt;

19 - a power shaft;

20 - protective soundproof casing of the drive shaft;

21 - a protective casing of a driving belt;

22 - the investigated object - ICE;

23 - vertical adjustment rack of the engine mounting system on the stand;

24 - a longitudinal beam of the engine mounting system on the stand;

25 - housing of the upper support bearing assembly;

28 - a frame of a supporting power frame;

31 - shaft of the upper support bearing assembly;

33 - intermediate bearing support;

34 - thrust bearings;

35 - an intermediate shaft;

36 - crankshaft.

The laser alignment device is made in the form of a single module (see figure 4-7), containing the base 37, a cylindrical body 38, in which the laser diode is rigidly mounted. The base material 37 contains a permanent magnet in the form of a “magnetic” suction cup. The laser alignment device module is rigidly mounted on a mounting pad made of ferromagnetic material due to the attractive magnetic field arising between the surface of the pad 39 and containing a permanent magnet with the base 37 so that the luminous beam 40 is directed to the center (axis of rotation) of the end section of the transition shaft 41 rigidly connected to the shaft 31 of the upper pillow block bearing assembly. The surface of the mounting pad 39 should be perpendicular to the axis of rotation of the mating shafts 31 and 41. In this case, the angle between the invisible laser beam 42 and the plane of the flange 43 of the adapter shaft 41 is 90 °. For the option of arranging the axis of rotation of the crankshaft of the ICE under investigation perpendicularly (opposite) to the surface of the entrance door of the test chamber, the surface of the entrance door can be used as an installation site for installing the laser device module. In this case, it means a sheet steel door or a plate containing a ferromagnetic substance. When the internal combustion engine is mounted on the bench, the position of the module of the laser alignment device remains unchanged, and the drive shaft 19, rigidly connected to the intermediate shaft 35, is set so that the luminous bundle 40 is directed to the center (axis of rotation) of the end portion of the intermediate shaft 35 of the intermediate bearing support

(see figure 5). The next step is to couple the ICE under study with an intermediate bearing support and select, using adjustments, the vertical struts and the transverse guides of the ICE fastening system on the bench of the ICE position so that the luminous bunch 40 is in the center (axis of rotation) of the crankshaft nose 36 (see Fig. 6 ) The alignment of the axes of rotation of the mating shafts indicated above (crankshaft 36, countershaft 35, drive shaft 19) carried out in this way is highly accurate and allows, ultimately, minimizing the generation of additional vibration forces at the frequencies and ordinal harmonics of rotation of the mating shafts with a significant weakening of vibrational excitation bearing structures of the motor stand and building elements of the test chamber and the reduction of spurious noise emissions.

For the location of the rotation axis of the crankshaft of the ICE under study opposite the blind wall of the test chamber, the mounting platform 39 (see Fig. 7) of ferromagnetic material is mounted on this wall 6 by means of bolts 44. After the alignment of the mating shafts, the blind wall section of the anechoic acoustic the chamber is closed by a removable sound absorber 45 of the type of used sound-absorbing lining (wedges, wings) of the surface of the acoustic anechoic chamber, which is mounted on an outboard screw 46. For periodic calibration adjustment of the coordinates of the location of the module of the laser alignment device, on the surface of the mounting platform 39 contains a calibration mark 47, having the form of a projection of the base of the laser alignment device on the surface of the mounting site.

The practical implementation of the proposed design of the motor stand for vibroacoustic testing of internal combustion engines allows you to ultimately increase the accuracy and objectivity of the results of bench vibroacoustic studies of internal combustion engines.

Claims (4)

1. A motor stand for vibro-acoustic testing of an internal combustion engine, comprising, in particular, an anechoic acoustic chamber, an internal combustion engine mounting system with a test internal combustion engine mounted on a test bench, test drive elements kinematically connecting the internal combustion engine crankshaft with a drive shaft of a brake balancing asynchronous test machine, the fact that the motor stand contains a laser device for centering the axes of the mating shafts (the drive shaft of the brake balancing asynchronous machine and the crankshaft of the ICE under study), made in the form of e a module containing a base and a cylindrical body with a laser diode rigidly mounted in it, while the base contains a permanent magnet in the form of a “magnetic suction cup” and is mounted on a mounting pad made of ferromagnetic material, the plane of which is perpendicular to the axis of rotation of the drive shaft of the brake balancing asynchronous machine and the luminous beam of the laser beam is directed to the center (axis of rotation) of the end portion of the specified drive shaft; the surface of the mounting pad contains a calibration mark for periodically calibrating the alignment coordinates of the laser alignment device module. 2. Motor stand for vibro-acoustic testing of the internal combustion engine according to claim 1, characterized in that the mounting pad is the surface of the entrance door of the test chamber. 3. The motor stand for vibro-acoustic testing of the internal combustion engine according to claim 1, characterized in that the mounting pad is mounted on a blank wall of the test chamber. 4. The motor stand for vibro-acoustic testing of the internal combustion engine according to claim 3, characterized in that the portion of the blank wall of the anechoic acoustic chamber with the mounting pad mounted on it contains a removable sound absorber such as the sound-absorbing lining (wedges, wings) of the surface of the acoustic anechoic chamber.