Mouldable acoustic devices

Abstract: Mouldable acoustic devices internally coupled to a vehicle engine's air filter relates to a mouldable acoustic box (5), comprised of a plate of porous acoustic absorbing material or a set of plates of porous acoustic materials, superimposed and glued to each other, having its shape predetermined pursuant to the internal and acoustic characteristics of the conventional air filter to which it will be internally coupled, the device (5) being essentially an acoustic internal lining having the purpose of absorbing acoustic waves generated by inlet noises, that is coupled inside the air filter's upper compartment (1) and/or lower compartment (2), the device (5) being optionally removable f vrom the relevant compartments.

Description: The present invention relates to mouldable acoustic devices, and in particular to mouldable acoustic tubular lining devices made of sound-absorbing material or a set of sound-absorbing materials, which has the shape thereof predetermined according to the internal characteristics of vehicle engine air inlet components, such as air filter of an automobile, pickup truck, truck or the like. As is known in the automotive industry, there are known acoustic devices to be located in the interior of a vehicle engine's air filter, which can he, for example, known sound-reducers or truncated-cone sound reducers made of plastics or metal, which are generally coupled around circular openings (1-A1, 2A1) - see Figure 1 annexed hereto, showing a lateral cross-section of a type: of conventional air filter - made respectively on one side of the air filters upper compartment (1) and lower compartment (2), the air filter element (3) being compressed between the two compartments (1,2) and the internal supports for said air filter element (3). Patent EP-A-0 435 588 is characterised by an unitary pipe with internal lining comprising by tissue layers of porous material and rubber material, i.e., a pipe in a unique module, which is set to replace the previous existing dirty air pipe in the filter end, which catches external dirty air and brings it into the air filter. Thus, contrary to the this invention, it is not a specific pipe which is set perfectly in another pipe, and even less set in the clean air pipe but a specific pipe set to replace the dirty air pipe if the air filter end, as it is clearly shown in figure (1), generates a totally different conception of the present invention, as it is a way to build a suppressing pipe made essentially in rubber used in the dirty air pipe of the filter set, without reference to the sound suppression in the part of the clean air pipe. Patent DE 3429633A is characterised by a set perforated plates or not in rigid material perfectly set slightly inclined in the air filter pipe to cause a set of pre-chambers in the same, causing a new constructive disposition on the air filter. These have the function of reducing the noise by dispersing the air flow, with direct influence in the air path through its conduction and re-direction, reducing the noise by treatment of the air flow. Together with these plates it is glued an absorbent material in one part of the internal face of the air filter. Thus, in this way, contrary to the invention, it is not a specific suppressing device which are set perfectly in the air filter without attaching, moulding or fixing in the internal surface of the same, causing an air mattress between the external and the internal surface if the air filter which does not influence at any moment the air flow but a set of plates which cause pre-chambers, and function based on the influence on the air path and an absorbent glued in parts of the internal surface of the air filter, as it is clearly shown in the figures, causing a totally different conception of the requested in the patent, since it is a constructive shape for the air filter which causes pre-chambers to disperse and divide the air flow, in order to create an sound suppression effect. Patent DE-A 37 07 617 is characterised by a pipe formed by compact material, with its internal smooth face and having a set of small longitudinal bar set on its external surface which are fixed along the internal surface of the dirty air pipe, i.e. it causes a complete coupling with this pre-existant dirty air pipe in the end of the filter, which catches external dirty air and brings it into the dirty air filter having its function based not on the porosity of its material, but more directly by its acomodation to the body of its structure as an weakener, with deformations on the same by the causing of internal pressure, causing compression and decompression. Thus, in this way contrary to the patent application it is not a specific pipe, only it is set perfectly in another pipe without attaching, moulding or fixing in the internal surface of the same, i.e. without having any contact and lot less it is set in the clean air pipe and functions through the trespassing of its structure by sound, but a pipe with external bars fixed along the internal surface of the dirty air pipe of the end of the air filter which functions by deformation of its surface as it is clearly shown on figure (2), causing a different conception of the one requested in the patent, as it is an coupling and not inserting. Patent WO 93 19291A is characterised by a silencer box inserted and interposed in any place along the clean/dirty air pipes containing an internal piping and a complete filing in absorbing foam material, lining completely this internal piping, being this the main filing responsible for the noise suppression. Thus, contrary to the invention it is not a specific pipe which is set perfectly in another pipe without attaching, moulding or fixing in the internal surface of the same, i.e. without having any contact with the same, but a traditional silencer box, as it is clearly shown in the figures, causing a totally different conception of the one of the requested patent, as it is a internal silencer to the air filter, produced from a combination of acoustic materials in foam shape. With these descriptions and comparisons can be seen that the object of present invention and the objects of the above mentioned patents are completely different. It should be pointed out that the present invention sound suppressing devices do not influence in any way the air path; they are inserted and not attached, moulded or fixed in the internal surface of the elements. The sound suppressing devices cannot suffer disintegration as they are positioned after the filter therefor they do not the filter residues influence. They are spare parts being possible to add them at any moment to the elements. they function by the sound passing through their surface and generation of air mattresses. In the arrangement shown in Figure 1, the air is aspirated by the dirty air inlet nozzle (1-A) of the upper compartment (1) and in the aspiration sequence - indicated by the larger arrows (S-1) the air passes through the noise reducer or truncated cone shaped sonorizer - not shown on the Figure - coupled around the circular opening (1-A1), enters the upper compartment (1), then passes through the filtering element (3), enters the lower compartment (2) of the filter and passes through the noise reducer or truncated cone shaped sonorizer of the lower compartment (2) that is coupled around the circular opening (2-A1), entering the purified air exit nozzle (2-A) and then into the vehicle's engine, whereby, simultaneously and inversely to the trajectory described above, there is a sequence of inlet noises by means of sound waves - shown sequentially by bold arrows (S-2) which finally exit through the filter's upper compartment (1) dirty air inlet nozzle (1-A). However, such internal noise reducers or truncated cone shaped sonorizers are integral parts usually made of plastics or metal, these materials being non-acoustical but rather noise propagators, such reducers or sonorisers allowing by reason of their truncated cone shape only a modest damping of the inlet noises - by breaking up the sound waves - and that includes the engine's and air aspiration noises, exiting through the dirty air inlet nozzle (1-A). There are also known acoustic devices which may be located in the outer part of the air filter, which can be for example, tubes or boxes that control the air input to the engine and which are arranged upstream of the air filter, coupled to the nozzle (1-A) of the dirty air inlet of the air filter's upper compartment (1). The above-mentioned conventional acoustic devices are intended to reduce the inlet noises. Referring to Figure 2 (where like parts to those shown in Figure 1 are generally denoted by like reference numerals), a conventional clean air passage tube (8) made of rubber or plastics, which is coupled to the clean air exit nozzle (2-A) of the air filter's lower compartment (2) and to the carburetor nozzle (6) comprises merely a leak proof tube (8) that ensure a seal for the conducted air. However, the fact that the tube (8) is typically made of rubber or plastics causes it to transmit the engine noise via the filter: because the clean air passage tube (8) Interconnects the air filter and the carburetor (6), it is an integral part of the vehicle engine inlet assembly. The use of known external, acoustic tubes or boxes, and internal noise reducers or truncated cone shaped sonorizers. do not in practice achieve the desirable technical effect of noise reduction, because being typically made of plastics or metal, they do not absorb the acoustic waves to the required degree. Further more, the addition of tubes or boxes contributes to increase the cost of production and also takes up excessive space in the engine compartment. The mouldable acoustic device of the present invention ameliorates the deficiencies with known arrangements. The invention is defined in the appended independent claims with preferred features being set out in the subsidiary (dependent) claims. A first comparison embodiment comprises a mouldable acoustic device internally coupled to a vehicle engine's air filter, being coupled inside an air filter provided with an upper compartment (1) having a dirty air inlet nozzle (1-A) and a circular opening (1-A 1 ) made on the wall of compartment (1) the air filter element (3) being pressed between the filter's upper (1) and lower (2) compartments and the internal supports (4) of said air filter element, with a circular opening (2-A1) made on the wall of compartment (2), followed by purified air exit nozzle (2-A1) towards the inside of the vehicle's engine, the acoustic device being made by moulding, thermo-pressing machine or any other appropriate manufacture process, with a predetermined shape, according to the internal and acoustic characteristics of the type of air filter in which it will be applied, the mouldable, acoustic device preferably comprising porous acoustic absorbing material, preferably comprising a lining of one or more sheets or plates of said material. The mouldable acoustic device therefore comprises an acoustic internal lining that can assume several shapes - compatible with the internal and acoustic shapes of the conventional air filter to which it will be internally coupled (typically by gluing) - the device being therefore a stamped or thermoformed part (optionally removable), that can be coupled inside the conventional air filter's upper compartment or lower compartment. Further preferred features can be better understood by reference to Figure 3. which shows a lateral cross-section of a conventional air filter provided with an upper compartment (1) having a dirty air nozzle (1-A1) and a circular opening (1-A1) made on the wall of compartment (1), the air filter element (3) being pressed between the filter's upper (1) and lower (2) compartment and the internal supports (4) of the air filter element, there being a circular opening (2-A1) made on the wall of compartment (2), which is followed by a purified air exit nozzle (2-A) towards the inside of the vehicle's engine. As shown a Figure 3, the mouldable acoustic device forms a lining box (5) (of generally square, circular or any other suitable shape conforming to the interior of the filter), that is coupled (typically by gluing) to the inner surfaces of the air filter's upper compartment (1), with a circular lateral opening (5-A) coinciding with the circular lateral opening (1-A1) of the upper compartment (1) and also coinciding with the circular lateral opening (2-A1) of the lower compartment (2), the lining box (5) being open in the direction of positioning with the air filter element (3). Accordingly, the device is mouldable in the shape of a lining box (5) of required shape, that internally lines the air filter's upper (1) and lower (2) compartments, or may line only one of these two compartments (1 or 2). It should be explained that the mouldable acoustic device in the shape of a lining box (5) comprises a porous acoustic absorbing material or more than one porous acoustic material advantageously in a sheet or plate form. By way of example, in the case where only one acoustic absorbing material is employed in the manufacture of the mouldable lining device (5), this material can be a non-- woven, porous and/or treated sheet, fibrous material or plate (for example, of polyester). Also by way of example, in the case where a set of acoustic materials is employed in the manufacture of the mouldable device (5), this set of materials can comprise superimposed lining sheets or plates glued to each other, made, for example, of porous paper, perforated aluminium or cotton tissue. For manufacture of the mouldable acoustic device (5) is employed a mould, a thermo-pressing machine or another appropriate manufacturing process. It should be emphasised that for each type of conventional filter a study of its acoustic characteristics is made in order to allow the proper moulding of the acoustic, box-shaped liming device (5) applicable thereto. The technical effect caused by the mouldable acoustic lining device (5) is that of absorbing the sound waves: the invention has shown a significant decibel gain in respect of prior art noise reducers or truncated cone shaped sonorizers made of plastic or metal, and acoustic external tubes or boxes. The absorption of sound waves by the device (5) is illustrated in Figure 3, whereby the sound waves - sequence of bold arrows (S-2) - coming from the vehicle's engine through the purified air exit nozzle (2-A) enter the filter's lower compartment (2); and are initially absorbed by the device (5), as shown by the small sinuous arrow (S-3), the sound waves - already partially absorbed - passing to the upper compartment (1) through the air filter element (3), and in the upper compartment (1) are again absorbed by device (5), as shown by the small sinuous arrow (S-3) and subsequently the sound waves, with a significant decrease in intensity, as shown by arrows (S-4), exit through the dirty air inlet nozzle (1-A). In an embodiment, an improved mouldable acoustic tubular device has been developed to solve the technical deficiency relating to the prior art clean air passage tube (8) shown in Figure 2. As shown in Figures 4 and 5, the device comprises an acoustic, internal, tubular lining device (7) having a predetermined shape, in accordance with the internal characteristics of the clean air passage tube (8), wherein, the acoustic tubular lining device (7) will be applied internally by adhesive or the like, typically remaining fixed to the inner portion of tube (8), inner portion, the acoustic tubular lining, device (7) being capable of being applied partially or totally along the tube (8) inner portion, also with an end thereof extending beyond the tube (8) limit, in the coupling thereof to the clean air exit nozzle (2-A). Figures 4 and 5 show an inlet assembly, the mouldable acoustic tubular device (7) is applied inside the clean air passage tube (8) by partial coupling, it being noted that in this example of application to the acoustical tubular device (7) - also shown separately on Figure 4, which shows a lateral cross-section of: tube (8), having the device (7) internally coupled thereto - is given a straight tubular shape. One end (7-A) of device (7) extends beyond the limit of the tube (8) mouth and penetrates (7-A) inside the lower compartment (2) clean air exit nozzle (2-A) of the conventional air filter, being able to penetrate inside said clean air compartment (2). Figure 2 also shows the sequence of aspiration of dirty air - shown by larger arrows (S-1); accordingly, the air drawn by dirty air inlet nozzle (1-A) passes through the upper compartment (1) and through the filtering element (3); the already cleaned air then enters,the air filter's lower compartment (2), and the clean air flow - shown by larger arrows (S-2) passes through the clean air exit nozzle (2-A) and subsequently through the inner portion of the acoustic tubular device (7) and the clear: air passage tube (8) and thence to the vehicle engine's interior, through the carburetor (6), whereby, simultaneously and inversely to the trajectory described above, a sequence of inlet noises takes place by means of sound waves - shown in sequence by bold arrows (S-3) which will be initially absorbed by the acoustic tubular device (7) and subsequently absorbed by the conventional acoustic and internal devices coupled inside the air filter's lower (2) and upper: (1) compartments, and finally absorbed by the conventional external acoustic devices coupled; around and outside the dirt air inlet nozzle (1-A). It should be pointed out, that, depending on the acoustic attenuation desired for the inlet assembly, the acoustic tubular device (7) may entirely or partially dispense with the utilisation of the above-mentioned conventional acoustic devices. Figure 5 is a lateral cross-sectional view of the conventional clean air passage tube (8), having the mouldable acoustic tubular device (7) applied by total coupling to the interior thereof, it being noted that in this example of application of the device (7) a tubular shape is provided in accordance with the internal and broken characteristics of the conventional tube (8). It is further noted that in this example, the end (7-A) of device (7) does not extend beyond the limited of the tube mouth (8) whereby, as result, the end (7-A) will not penetrate the inside of the clean air clean nozzle (2-A) of the conventional air filter, as could penetrate nozzle (2-A) and the clean air compartment (2). It should be explained that the mouldable acoustic tubular device (7) is manufactured of an acoustic absorbing material provided with pores, or manufactured with a set of acoustic materials, all having controlled porosity. As an example, in the case where only one acoustic absorbing material in the manufacture of the mouldable acoustic tubular device (7), this could be porous, non-woven polyester. Also as an example, in the case where a set of acoustic materials are employed in the manufacture of the mouldable acoustic tubular device (7), this set of materials could comprise porous paper, perforated aluminium and cotton tissue superimposed to and glued to each other. For the manufacture of the mouldable acoustic tubular device (7) is employed a thermo-pressing machine, or a mould, or a circular weaving machine, of another appropriate manufacture process. The technical effect caused by the mouldable acoustic device (7) is that of absorbing the sound waves, it being observed that in the device (7) has shown excellent acoustic conditions, whereby an intake assembly employing the device (7) inside the clean air passage tube (8) there will be a significant decibel gain.

Claims: A sound absobing device for air intake component (1, 2; 8) of a vehicle engine comprising an acoustic absorbing material (5, 7), , the said acoustic absorbing material (5, 7) is arranged inside and attached to the internal walls of the said air intake component (1, 2; 8) and is configured according the internal and acoustic characteristics of the said air intake component (1, 2; 8), characterised in that the said device (7) is made of a porous sound absorbing material and having an outer face juxtaposed with the inner peripheral surface of a clean air tube (8) and is partially or totally attached along the inside of said tube (8), with an end (7-A) extending beyond the limit of said tube (8) into a coupling with the clean air exit (2-A). The acoustic device according to claim 1, characterised in that said sound absorbing device (7) is a sheet or plate, configured with tubular shape. An acoustic device according to claim 1 or 2, characterised in that is said acoustic absorbing device (7) consists of a plurality sheets or plates, configured with tubular shape, which are superimposed and bonded to one another. An acoustic device according to claims 1, characterised in that the said acoustic absorbing device (7) is mouldable by a thermo-pressing process. An acoustic tubular device according to claim 1-4, wherein the tubular device (7) is an acoustic internal lining, e.g. typically applied by gluing, to the inside of the clean air tube (8). The device according to claims 1-5 characterised in that said outer face of said sound absorbing device (7) has an upstream end (7-A) extending into the clean air nozzle (S-2). The device according to claims 1-6 characterised in that said outer face of the sound device (7) has an upstream end (7-A) extending into said filter compartment (2). The device according to claims 1-7 characterised in that a downstream end of said outer face of said sound absorbing device (7) terminates upstream from a downstream end of said tube (8). The device according to claims 1-8, characterised in that said sound absorbing device (7) extends from said tube (8) and terminates upstream from an upstream end of the clean air nozzle (S-2).

Inventors: LEPOUTRE EDMOND POL JEAN, LEPOUTRE, EDMOND POL JEAN
Applicants: WESTAFLEX TUBOS FLEXIVEIS LTDA, WESTAFLEX TUBOS FLEXIVEIS LTDA.
Application year: 1997
Main classification: F02M35
IPC codes: F02M35