5

FIELD OF THE INVENTION

[001] The present invention relates to an air filter system for internal combustion engines, to a filtering 10 element and to a supporting structure for a filtering element, which improve the mounting and replacement of air filters in addition to reducing the wastage of raw material involved in parts subject to little wear during the use and service life of air filters.

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BACKGROUND OF THE INVENTION

[002] Internal combustion engines use a controlled mixture of air and fuel, said mixture being defined in

20 accordance with the intended purpose and performance level expected of the engine, having regard to the fact that variation in the point of a stoichiometric mixture directly influences the power extracted by the explosion inside the combustion chamber, as a function

25 of energy utilization resulting from the burning and consumption of fuel.

[003] A further factor that influences the quality of burning and also the service life of the engine is the

30 quality of the fuel and of the air drawn inside the combustion chamber. Where fuels are concerned, there is an infinite range of factors that may influence their quality, such as: fuel refinement quality; quantity of components and additives mixed therewith; and the

35 presence of particulate foreign bodies. In terms of air quality, there are usually fewer quality-influencing external factors, considering that (at least in the case of engines used in vehicles) engines operate under atmospheric conditions and thus small modifications in the composition of the air occur from one place to another, such variations being negligible in terms of the proper functioning of the engine. [004] One condition involved in any atmosphere, however, is the presence of particulates and dirt present in the air, such as dust, soot, and sand, amongst others. Should these particulates enter the engine during its operation, the damage caused may give rise to a drop in the performance of the engine and may, in certain cases, even be irreversible. Examples of effects that may arise owing to the ingress of dirty air inside the combustion chamber are the formation of sludge, or the scoring of the walls or piston rings or jacket, which may have an impact in the form of a loss of compression in the combustion chamber.

[005] With a view to preventing the ingress of particulates present in the fuel, filters are installed between the tank and the injection nozzles, and, to prevent the ingress of particulates present in the air, filters are installed between the atmosphere and the air inlet of the combustion chambers. Such filtering elements have to be replaced from time to time, before they become saturated, since in such cases the filtering element not only impedes the passage of the filtered fluid but can be damaged and then allow the ingress of foreign bodies, thereby becoming inefficient .

[006] Air filters of heavy vehicles are commonly installed attached to the chassis longitudinal bar or, alternatively, behind the truck cab. For this reason, it is often difficult to access the parts that require periodic maintenance, either owing to other parts obstructing physical access or viewing of the part or, furthermore, owing to mounting positions that complicate the ergonomics of the task, such as in situations where the cover of the air filter faces downwards, close to the ground. Air filters are usually installed close to engines, and therefore under the vehicle bonnet. For this reason, the replacement of these components tends to be simple and rapid.

[007] One drawback that might occur is the risk that, when the filter is removed, certain particulates may fall inside the intake duct covered by the filter without the operator noticing. Such particulates may be present on the actual external wall of the filter, in the atmosphere in the workshop or even in the filter mounting structure, and signs of its presence inside the engine will become apparent only after damage has been caused thereto. With a view to overcoming this drawback, some prior art solutions, such as those disclosed in documents DE102014012948 and US8864865, comprise an additional filtering element mounted downstream of the principal filtering element, with the aim of covering the air inlet when the principal filter is removed, in addition to acting as a "back-up filter" should the principal filter become damaged during operation. It should furthermore be noted that the solution proposed by DE102014012948 makes it difficult to remove/replace the internal structure, which, because it is engagement-mounted, may suffer breakage if it is forced, potentially damaging the entire structure and generating undesired expense as a result of complete replacement of the structure. Moreover, that which is proposed by DE102014012948 requires a filtering element provided with an integral sealing ring . [008] A further drawback arises when air filters are changed, arising from their commonly being made from paper and therefore not being very rigid when handled. If the operative does not take care, such filters may be squashed or even torn, making them unusable. In such cases, there is also a risk that the operative will not notice that this damage has occurred and will install the defective filter, with operation being compromised over long periods until the next service or when a fault arises with the engine.

[009] In this connection, some solutions, such as those described in the prior art, already disclose filters with structural reinforcements, which are composed of polymeric material. However, this solution gives rise to a further drawback, namely the unnecessary discarding of material in good condition when the filter is replaced, because polymeric structures have a high level of mechanical strength and do not wear out in the course of the filter being used and could therefore be used for many more years, and perhaps for as long as the entire service life of the engine.

[010] Certain prior art solutions, as disclosed in documents US8864865 and EP1558360, which aim to obviate this drawback, disclose solutions that separate the filtering element from the structure thereof, it being possible to replace only the filtering element. However, document US8864865 discloses the supporting structure for the filtering element as being an integral part of the external structure, which means there is a need to replace the entire structure of the filter system in the event that the structure of the filtering element ruptures, giving rise to greater maintenance costs and the unnecessary exchange of parts that are still operating perfectly well. Furthermore, the solution proposed by document EP1558360 relates to a complex mounting system with a high number of associated parts, each comprising individual mounting means and regions.

[Oil] It should be noted, however, that the separation of these components may give rise to misalignment thereof during mounting, especially if there is an ideal operating position and, furthermore, may result in excess relative movement between the components during operation of the engine, on account of engine vibration or the traffic balance of the vehicle using it. A drawback of this type gives rise to noise generation and to the risk of friction-wear of components, and may reduce the service life of the filtering elements. In addition, the excessive number of parts and the excessive complexity of the system may give rise to greater potential leakage.

[012] Thus, the present state of the art lacks an air filter system at the intake of internal combustion engines that is capable of providing a unified solution for all the above-mentioned problems, resulting in a system and filter that is durable in the long term, and easy and precise to install and to replace, and also of making provision for the responsible use of resources, minimizing discarding of components having parts still in good condition.

OBJECTS AND DESCRIPTION OF THE INVENTION [013] Therefore, an object of the present invention is to provide an air filter system provided with a filter with an independent internal structure, with a view to minimizing premature discarding of parts that are still in a good state of preservation.

[014] It is a further object of the present invention to provide an air filter system comprising a back-up filter to prevent the ingress of particulates when the principal filter is being replaced and, furthermore, to act as principal filtering element in those cases where the principal filter is damaged in the course of use.

[015] A further object of the present invention is to provide an air filter system that allows the segmentation of the conventional parts of a filter system and guarantees the association thereof in a simple and effective manner, preventing the occurrence of drawbacks such as: mounting in an incorrect position; detachment during operation; noise generation; inter alia.

[016] One or more of the above-mentioned objects, inter alia, of the present invention will be achieved by means of an air filter system comprising: an external structure; an internal structure associated in a cooperating manner with the external structure, the internal structure being provided with openings capable of allowing the passage of a fluid to be filtered; and a principal filtering element arranged between the external structure and the internal structure, the internal structure, the external structure and the principal filtering element being associated with one another by means of engagement of mounting guides, it being possible for the mounting guides to be associated with one another in order to confer synchronism on the relative angular movement between the assembly formed by the internal structure and the principal filtering element, and the external structure.

[017] One or more of the above-mentioned objects, inter alia, of the present invention will be achieved by means of a filtering element of an air filter of an engine, comprising: at least one mounting guide region for juxtaposed engagement of the filtering element with an internal structure of an air filter of an engine; and at least one sealing region between an inlet region for fluid to be filtered and an outlet region for filtered fluid.

[018] One or more of the above-mentioned objects, inter alia, of the present invention will be achieved by means of a supporting internal structure for a filtering element of an air filter of an engine, comprising: a fluid passage region; a filtering element guide region; and a region for affixing to the external structure, wherein: the fluid passage region is provided with openings capable of allowing the passage of the filtered fluid; the filtering element guide region is provided with a mounting guide projection for engagement in a mounting guide recess of the filtering element; and the region for affixing to the external structure is provided with a support base and at least one region for engagement with the external structure.

BRIEF DESCRIPTION OF THE DRAWINGS

[019] The objects, technical effects and advantages of the present invention will become apparent to persons skilled in the art from the following detailed description that makes reference to the appended figures that illustrate exemplary but non-limiting embodiments of the invention: - Figure 1 shows an external perspective view of an embodiment of the air filter system of the present invention ;

- Figure 2 shows an upper, sectional view of the air filter system shown in Figure 1; - Figure 3 shows an embodiment of the supporting internal structure for a filtering element, according to the present invention; - Figure 4 shows a perspective view of the side of the air filter system of Figure 1, but without the front cover and comprising, mounted within, only the supporting internal structure of the filtering element; - Figure 5 shows an embodiment of the principal filtering element, according to the present invention;

- Figure 6 shows a detailed view of the interior of the rear cover, in the region designed to receive the mounting of the supporting internal structure for the filtering element;

- Figure 7 shows a detailed view of the guide region of the filtering element and the front cover of the air filter system;

- Figure 8 shows a detailed view of the overall association of the supporting internal structure guide region for a filtering element, of the principal filtering element and of the back-up filtering element;

- Figure 9 shows a perspective view of an embodiment of the back-up filtering element of the present invention. The presence of item 60 is optional. The exclusion of this item does not affect correct functioning of the system;

- Figure 10 shows a perspective view of the filtering element of Figure 9, mounted in a supporting internal structure for the filtering element; - Figure 11 shows a perspective view of an embodiment of the back-up filtering element of the present invention; and - Figures 12a and 12b show a perspective view of the filtering element of Figure 11 mounted in a supporting internal structure for the filtering element.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[020] Initially, it should be pointed out that the filtering element, the supporting internal structure for the filtering element and the air filter system that are the subject of the present invention will be described below in accordance with particular embodiments that are, however, non-limiting because the implementation thereof may be achieved in different forms and with different variations and in accordance with the use desired by the person skilled in the art as a function of engine geometry and filtering capacity, amongst other variables.

[021] For the purposes of the present invention, "filtering element" will be understood to mean not only the principal filtering element 50 but also the back-up filtering element 60, since, in either of these embodiments, the filtering element of the present invention comprises the same central structural features, namely: a geometry capable of allowing juxtaposed mounting on an internal structure 40; and at least one sealing region capable of preventing fluid communication between an inlet region for fluid to be filtered and an outlet region for filtered fluid. [022] "A geometry capable of allowing juxtaposed mounting on an internal structure 40" is understood to mean the geometry of the filtering element when associated with the internal structure 40, said association being achieved in a juxtaposed manner, with minimum clearance and adjustment such as to allow mounting and removal of parts without the use of excessive force, which could give rise to accidental damage thereof, generating difficulties and problems in terms of mounting, which conflicts totally with the objects achieved by the present invention. [023] The mounting guide regions 55, 65 for engagement of the filtering element with the internal structure 40 are regions along the surface of the filtering element, which surface is provided with physical features that result in conditioning of direction and/or conditioned limitation of degrees of freedom between one component and another, in the present case between the filtering element 50, 60 and the internal structure 40. This concept also applies to other embodiments of the invention, where the mounting guide region 15, 45, 55, 65 is present in at least one of the components of the air filter system, which components are defined by: front cover 10, internal structure 40, principal filtering element 50 and back ^¬ up filtering element 60, acting as mounting guide, for correct positioning, and guide for limiting relative movement between the parts, facilitating the locking thereof with one another and/or with the rear cover 30, and also preventing the propagation of vibrations arising from engine vibration or the passage of the vehicle over road surfaces.

[024] In one embodiment of the present invention, the mounting guide region 55, 65 is defined by a projection/recess made in the surface of the filtering element, with a geometry compatible with the projection/recess geometry of a mounting guide region 15, 45 arranged on the internal 40 and/or external 20 structure, for example on the mounting cover 10, of a filter system 1.

[025] In one embodiment of the present invention, the back-up filtering element 60 comprises a mounting guide 65 at one of its ends and a flange 62 at the opposite end, said flange 62 being provided with a sealing ring 64 at its external edge for preventing the fluid to be filtered passing from the inlet region to the outlet region for filtered fluid by some means that is not the filtering path imposed by the principal 50 and back-up 60 filter.

[026] Said supporting internal structure 40 for the filtering element 50, 60 of the present invention consists in a structure responsible for conferring rigidity on the filtering element 50, 60, but this is an independent component and therefore not replaceable at the time when the filtering element 50, 60 reaches a level of dirt accumulated on the surface thereof that is above that which is desired/permitted for proper functioning of the engine. Thus, said internal structure 40 may, if well cared for when the filter is replaced, last throughout the entire service life of the engine.

[027] The internal structure 40 comprises: a fluid passage region; a filtering element guide region; and a region for affixing to the rear cover, wherein: the fluid passage region is provided with openings 46 capable of allowing the passage of the filtered fluid; the filtering element guide region is provided with a mounting guide projection 45 for engagement in a mounting guide recess 55, 65 of the filtering element 50, 60; and the region for affixing to the rear cover is provided with a support base 42 and at least one region for engagement with the rear cover. [028] The openings 46 that define the fluid passage region, in one embodiment of the present invention, and also as shown more clearly in the figure, are formed by a plurality of adjacent openings spaced longitudinally and radially over a cylindrical surface of the internal structure 40. Thus, as shown in Figure 3, in one embodiment said openings 46 are the result of the spacing of a plurality of structural reinforcements 41, such as a grille that forms a basket. This embodiment allies structural rigidity with a high level of open surface, allowing the passage of a high volume of filtered fluid with a low pressure drop. [029] In one embodiment of the present invention, the internal structure 40 comprises a sealing region 44 capable of preventing fluid communication between an inlet region for fluid to be filtered and an outlet region for filtered fluid, and more precisely said sealing region is arranged along the periphery of one of the ends thereof, being able, optionally, to work in conjunction with the sealing ring 64 of the back-up filtering element 60. [030] The association of the internal structure 40 with the rear cover 30 must be as simple and as rigid as possible, since mounting errors or clearances between the association of these elements may give rise to drawbacks such as the friction-wear of contacting surfaces or undesirable noise, both resulting from vibration from functioning of the engine or even the balance of the vehicle as it moves.

[031] Thus, the internal structure 40 of the present invention comprises an engagement region, which is defined by the association between tangential projections 33 and tangential openings 43, which can be associated with and dissociated from one another by means of relative rotation between the internal structure 40 and the rear cover 30 and, consequently, the external structure 20. In one embodiment, the tangential openings 43 are arranged in the flange 42 of the internal structure 40 and the tangential projections are arranged in the support base 32 of the rear cover 30 of the external structure 20. [032] In this case, the internal structure 40 is mounted inside the external structure 20 and has its flange 42 bearing on the base 32. The internal structure 40 may be inserted with the filtering element (s) 50, 60 already installed thereunder, by means of the joint association of the respective mounting guides 45, 55, 65 thereof, and then the assembly defined by the internal structure 40 and the filtering element (s) 50, 60 rotated until the tangential projections 33 encounter the tangential openings 43 and lock together, preventing the axial, radial and rotational movement of the internal structure 40 relative to the external structure 20.

[033] Allied with the above-mentioned locking, in one embodiment of the present invention, the principal filtering element 50 comprises radial projections 56 that engage in locking housings 34 of the rear cover 30 when the filtering element 50, or the assembly defined by the internal structure 40 and the filtering element (s) 50, 60 is rotated inside the external structure 20.

[034] In one embodiment of the present invention, the association between the tangential openings 43 and the tangential projections 33, and between the radial projections 56 and the locking housings 34, arises by means of the relative angular movement between the assembly formed by the internal structure 40 and the principal filtering element 50, and the external structure 20. The axial pressure needed to ensure sealing between items 30, 40 and 50 is generated during the angular movement of item 40 coupled to the others, by means of the interaction between item 56 and the inclined plane of item 34.

[035] In one embodiment of the present invention, the internal structure 40 comprises the sealing ring 64 of the filtering element 60 around the edge of the flange 42, forming the sealing region. In another embodiment, the filtering element 50 comprises a sealing region 54 defined by a peripheral ring composed of deformable material, such as a low-density polymer, that is capable of providing a sealing region when in contact against a wall of the external structure 20.

[036] Thus, in one embodiment of the present invention as illustrated in Figures 1 and 2, the air filter system 1 of the present invention comprises: an external structure 20; an internal structure 40; a principal filtering element 50; and a back-up filtering element 60, the internal structure 40 being associated in a cooperating manner with the external structure 20, the back-up filtering element 60 being arranged so as to be juxtaposed with at least one surface region of the internal structure 40, and the surface of the internal structure 40 being provided with openings 46 capable of allowing the passage of a fluid to be filtered .

[037] Furthermore, the air filter system 1 comprises the internal structure 40, the external structure 20, the principal filtering element 50 and the back-up filtering element 60, which are associated with one another by means of the engagement of mounting guides 45, 55, 65, in which the association of the mounting guides 45, 55, 65 confers synchronism on the angular movement of the assembly formed by the association of the internal structure 40, the principal filtering element 50 and the back-up filtering element 60 inside the external structure 20.

[038] In one embodiment of the present invention, the assembly formed by the association of the internal structure 40, the principal filtering element 50 and the back-up filtering element 60, via the association of the mounting guides 45, 55, 65, is locked relative to the external structure 20 via the association of the mounting guides 45, 55, 65 with the mounting guide 15 affixed to the structure of the air filter system 1, such that, when the air filter system 1 is completely mounted, the association of all the mounting guides 15, 45, 55, 65 achieves the restriction of all the degrees of freedom of the internal structure 40 and of the filtering element (s) 50, 60 relative to the external structure without it being necessary, however, to achieve said affixing via affixing elements in operations requiring the use of tools or that are highly complex.

[039] Thus, the association of the mounting guides 15, 45, 55, 65 consists in the superposed mounting of complementary geometries arising, in one embodiment of the invention, in a single region of the assembly. For the purposes of the present invention, mounting "in a single region of the assembly" is understood to consist in the possibility of mounting the mounting guides 15, 45, 55, 65 so as to be superposed on one another such that the internal geometry of one serves as a guide for the mounting of the subsequent one, and so on. The advantage of including all the guide elements arranged in a single region of the assembly is that any forces are distributed homogeneously amongst all the associated components and furthermore the formation of mechanical forces between them is prevented. This mounting 15, 45, 55, 65 also acts as a failsafe system to prevent incorrect mounting.

[040] Lastly, it is noted that the object of providing an air filter system provided with a filter with an independent internal structure, with the aim of minimizing premature discarding of parts that are still in a good state of preservation, is fully achieved via the filtering element comprising: a geometry capable of allowing juxtaposed mounting with an internal structure; at least one mounting guide region for engagement of the filtering element with the internal structure; and at least one sealing region capable of preventing fluid communication between an inlet region for fluid to be filtered and an outlet region for filtered fluid, in addition to the supporting internal structure for a filtering element, comprising: a fluid passage region; a filtering element guide region; and a region for affixing to the external structure, wherein: the fluid passage region is provided with openings capable of allowing the passage of the filtered fluid; the filtering element guide region is provided with a mounting guide projection for engagement in a mounting guide recess of the filtering element; and the region for affixing to the external structure is provided with a support base and at least one region for affixing to the external structure.

[041] Finally, the object of providing an air filter system comprising a back-up filter for preventing the ingress of particulates when the principal filter is being replaced and furthermore acting as principal filtering element when the principal filter is damaged during use, in addition to an air filter system that allows the segmentation of the conventional parts of a filter system and guarantees the association thereof in a simple and effective manner, preventing the occurrence of drawbacks such as: mounting in an incorrect position; movement during operation; noise generation; inter alia, is totally achieved via an air filter system comprising: an external structure; an internal structure; a principal filtering element; and a back-up filtering element 60; the internal structure being associated in a cooperating manner with the external structure; the back-up filtering element being arranged in a juxtaposed manner with the at least one surface region of the internal structure, the surface of the internal structure being provided with openings capable of allowing passage of a fluid to be filtered; and the internal structure, the external structure, the principal filtering element and the backup filtering element being associated with one another by means of engagement of mounting guides, in which the association of the mounting guides confers synchronism on the angular movement of the assembly formed by the association of the internal structure, the principal filtering element and the back-up filtering element inside the external structure.

[042] Notwithstanding the description of the particular embodiments above, the present invention may be used for other uses and may be modified in terms of its form of implementation such that the scope of protection of the invention is limited only by the content of the appended claims, which include the potential equivalent variations.