Patent ID: 12257538

While the present disclosure is subject to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. The invention should be understood to not be limited to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one of ordinary skill in the art that the invention disclosed herein may be practiced without these specific details. In other instances, specific numeric references such as “first filter,” may be made. However, the specific numeric reference should not be interpreted as a literal sequential order but rather interpreted that the “first filter” is different than a “second filter.” Thus, the specific details set forth are merely exemplary. The specific details may be varied from and still be contemplated to be within the spirit and scope of the present disclosure. The term “coupled” is defined as meaning connected either directly to the component or indirectly to the component through another component. Further, as used herein, the terms “about,” “approximately,” or “substantially” for any numerical values or ranges indicate a suitable dimensional tolerance that allows the part or collection of components to function for its intended purpose as described herein.

A drawback to enclosed air boxes is that they typically conduct air through a tortuous path of hoses or ductwork before the air enters the intake of the engine. In some cases, the air box is a greater source of air restriction than is the paper filter. Similar to a contaminated air filter, a restrictive air box decreases engine performance and fuel economy. One solution to the restricted air flow encountered with enclosed air boxes is utilize an open air filter box for filtering and conducting an airstream to an air intake of an engine. The open air filter box typically is coupled with an air filter comprising a filter medium configured to entrap particulates flowing within the airstream. The open air filter box may be configured to be mounted, or fastened, onto the engine. An intake tube may be coupled with the air filter and configured to conduct the airstream to the air intake of the engine. Given that the open air filter box generally decreases air resistance to the air intake of the engine, there is a continuing interest in developing open air filter systems to improve engine performance beyond that otherwise possible with an enclosed air box. Embodiments provided herein disclose an air filter precleaner that includes a filter medium disposed between a base and a grating that are fastened over an opening into an interior of an air filter box.

Although embodiments of the present disclosure may be described and illustrated herein in terms of a cone air filter, it should be understood that embodiments of the present disclosure are not limited to the exact shape illustrated, but rather may include a wide variety of generally cylindrical shapes, generally circular, oval, round, curved, conical, or other closed perimeter shape, that provide a relatively large surface area in a given volume of the filter. Moreover, embodiments as described herein are not limited to use as internal combustion engine filters but may have applicability in other filtration systems in which a large volume of air needs to be treated.

FIG.1illustrates an exploded isometric view of an exemplary embodiment of an air filter precleaner100that is configured to be coupled with an aircharger air intake system102comprising an air filter box104configured to couple a cone-shaped air filter108to an air intake of an engine. The air filter box104comprises sidewalls112, a floor114, and a mount wall116that define an interior110of the air filter box104. In general, the air filter box104is comprised of a rigid material that is sufficiently durable and temperature resistant to retain its configuration during installation and operation when coupled with the air intake of the engine.

The air filter108comprises a filter medium that provides an area to pass an airstream and entrap particulates and other contaminates flowing with the airstream. The filter medium may be comprised of paper, foam, cotton, spun fiberglass, or other known filter materials, woven or non-woven material, synthetic or natural, or any combination thereof. The filter medium may be pleated, or otherwise shaped, or contoured so as to increase a surface area for passing the airstream to be cleaned. The length of the filter medium in the circumferential direction may be longer than the circular circumference of the air filter108generally, such that the surface area of the filter medium is greater than the profile surface area of the air filter108.

In some embodiments, the filter medium comprises 4 to 6 layers of cotton gauze sandwiched between two epoxy-coated aluminum wire screens. The cotton may be advantageously treated with a suitably formulated filter oil composition that causes tackiness throughout microscopic strands comprising the filter medium. The nature of the cotton allows high volumes of airflow, and when combined with the tackiness of the filter oil composition creates a powerful filtering medium which ensures a high degree of air filtration. Further details about components comprising the air filter108, as well as details about the filter oil composition, are disclosed in U.S. patent application Ser. No. 14/181,678, entitled “Air Box With Integrated Filter Media,” filed on Feb. 16, 2014, and U.S. patent application Ser. No. 14/701,163, entitled “Filter Oil Formulation,” filed on Apr. 30, 2015, the entirety of each of which is incorporated herein by reference.

The air filter box104generally is of an open variety, rather than being an enclosed air box as is conventionally utilized with many vehicles. The sidewalls112and the floor114serve to protect the air filter108from road debris, as well as to isolate the air filter108from hoses and other components that may be present within an engine bay of the vehicle. It will be recognized by those skilled in the art that the open air filter box104improves airflow to the air filter108, and thus decreases air resistance to the air intake of the engine, thereby improving engine performance beyond that otherwise possible with an enclosed air box. The air filter box104generally is configured to be mounted, or fastened, onto the engine by way of suitable fasteners. The fasteners generally may comprise any of suitably designed holes, brackets, molded shaped portions, protrusions, extensions, angled brackets, hardware fasteners, or other any similar device for supporting the air filter box104within the engine bay. It should be understood that the particular fasteners will vary according to the specific make and model of the vehicle with which the air filter box is to be used.

The mount wall116generally is configured to support the air filter108and provide an interface between the air filter108and the air intake of the engine. An opening120in the mount wall116is configured to receive an intake tube124that is configured to couple the air filter108with the air intake of the engine. In the embodiment illustrated inFIG.1, the intake tube124is coupled with the air filter108by way of an adapter126. Similarly, the intake tube124may be coupled to the air intake of the engine by way of an adapter128. It is contemplated that any of various suitable hardware fasteners may be used in combination with the adapters126,128to couple the air filter108and the intake tube124with the air intake of the engine. Further details regarding techniques for coupling the air filter108and the intake tube124, as well as for coupling the air filter108with the mount wall116are disclosed in U.S. patent application Ser. No. 16/405,747, entitled “Aircharger Air Intake System and Method,” filed on May 7, 2019, which is a continuation of, and claims the benefit of, U.S. patent application Ser. No. 15/794,909, filed on Oct. 26, 2017, which is a continuation of, and claims the benefit of, U.S. patent application Ser. No. 15/453,496, filed on Mar. 8, 2017, which claims the benefit of, and priority to, U.S. Provisional Application Ser. No. 62/305,391, filed on Mar. 8, 2016, the entirety of each of said applications being incorporated herein by reference and made a part of the present disclosure.

As further shown inFIG.1, the air filter box104includes an opening132to the interior110of the air filter box104. The opening132is bordered by a flat mating surface136upon which the air filter precleaner100may be installed, as described herein. It is contemplated that the opening132facilitates installing and removing the air filter108from the air filter box104, as needed. For example, once the air filter108is dirty, the air filter may be removed from the air filter box104and a new, clean air filter108may be installed. In one embodiment, a method for removing the air filter108comprises removing the air filter precleaner100from the surface136to provide access to the interior110of the air filter box104. Upon removing the air filter precleaner100, the air filter108may be removed from the interior110by way of the opening132.

Although the method for removing the air filter108generally facilitates replacing the air filter, when dirty, with a clean air filter, it is contemplated that the method for removing the air filter108is particularly advantageous for use with embodiments of the air filter108that are configured to be periodically cleaned and reused. For example, in some embodiments, the air filter108may be comprised of multiple layers of cotton gauze that are treated with a filter oil composition that enhances the filtration properties of the air filter. It is contemplated that a practitioner may clean the air filter108by first removing the air filter from the air filter box104, as described above, and then applying a solvent to remove the filter oil from the cotton gauze comprising the air filter108. The practitioner may clean the air filter108using a water hose to spray water so as to flush contaminants from the air filter. Further details about periodic cleaning of the air filter108, as well as details about the filter oil composition, are disclosed in U.S. patent application Ser. No. 14/181,678, entitled “Air Box With Integrated Filter Media,” filed on Feb. 16, 2014, and U.S. patent application Ser. No. 14/701,163, entitled “Filter Oil Formulation,” filed on Apr. 30, 2015, the entirety of each of which is incorporated herein by reference.

In the embodiment illustrated inFIG.1, the air filter precleaner100includes a filter medium140disposed between a base144and a grating148that are configured to be fastened over the opening132of the air filter box104. The filter medium140is configured for removing particulate matter from an airstream entering the air filter box104through the opening132. In general, the filter medium140comprises a sheet of filter material having a shape and a size suitable for being supported between the base144and the grating148. In some embodiments, the filter material140comprises a reticulated polyester urethane foam. The base144is a rigid member that includes a grate152surrounded by a border portion156that are configured to support the filter medium140in a sheet configuration, such that the airstream passes through the filter medium140before entering the interior110of the air filter box104. The grating148is a rigid member comprising a screen portion160surrounded by a frame164that is configured to be fastened onto the air filter box104. The grating includes a shape and a size suitable for fastening the filter medium140and the base144over the opening132of the air filter box104. The screen portion160comprises a shaped lattice configured to allow the airstream to pass through the filter medium140before entering the air filter box104. The filter medium140, the base144and the grating148are discussed in greater detail in the following paragraphs.

FIGS.4A,4B and4Cillustrate respective top, side and bottom plan views of an exemplary embodiment of the grating148that is configured to be implemented in the air filter precleaner100shown inFIG.1. The grating148is configured to couple the base144and the filter medium140onto the air filter box104, as well as to provide protection to the filter medium140from other components within the engine bay. As mentioned above, the grating148generally is a rigid member comprising a screen portion160surround by a frame164that is configured to be fastened onto the air filter box104. As shown inFIGS.4, the screen portion160comprises a shaped lattice that is configured to allow an inflowing airstream to pass through the filter medium140before entering the interior110of the air filter box104. In the illustrated embodiment ofFIGS.4, the screen portion160comprises a multiplicity of hexagon shaped openings168in the grating148. It is contemplated, however, that the openings168may include any of various shapes that are suitable for tessellating the screen portion160, without limitation.

The grating includes a shape and a size suitable for fastening the base144and the filter medium140over the opening132of the air filter box104. As such, the frame164generally includes a perimeter shape that is substantially similar to the shape of the mating surface136of the air filter box104. Further, the frame164includes a peripheral lip172that is configured to extend over an exterior of the filter medium140and the base144. In some embodiments, the peripheral lip172is configured to contact the mating surface136surrounding the opening132of the air filter box104. Further, a through-hole176is disposed in each of one or more corner portions180comprising the frame164are configured to facilitate fastening the grating148to the air filter box104. To this end, each of the through-holes176is configured to allow passage of a hardware fastener, such as a screw or bolt, into a hole184disposed in the mating surface136of the air filter box104. In some embodiments, the through-holes176may be counterbored to position a head portion of the hardware fastener below an exterior surface of the grating148.

As best shown inFIG.4C, each of the corner portions180includes an interior surface188that is configured to contact the border portion156of the base144. The interior surfaces188are configured to ensure that a space suitable for the filter medium140is disposed between the base144and the screen portion160once the peripheral lip172is extended beyond the base144and placed into contact with the mating surface136. Accordingly, the filter medium140includes corner cutouts192(seeFIGS.1and10A) that are configured to allow the filter medium140to be positioned adjacent to the interior surfaces188. Preferably, the filter medium140includes a thickness196(seeFIG.10B) that is suitable for being disposed within the space between the screen portion160and the base144provided by the interior surfaces188.

FIGS.5A,5B and5Cillustrate respective top, side and bottom plan views of an exemplary embodiment of the base144that is configured to be implemented in the air filter precleaner100shown inFIG.1. The base144generally is a rigid member comprising a grate152surrounded by a border portion156having a shape and a size suitable for being positioned within the peripheral lip172of the grating148and being fastened over the opening132of the air filter box104. The grate152is configured to support the filter medium140in a flat, sheet configuration between the base144and the grating148, such that an inflowing airstream passes through the filter medium140before entering the interior110of the air filter box104. As best shown inFIGS.5A and5C, the grate152comprises a framework of perpendicular elongate members200that are arranged to support the filter medium140in the sheet configuration.

The border portion156is configured to be placed into direct contact with the mating surface136surrounding the opening132of the air filter box104. As such, the border portion156includes a shape and a size suitable for being coupled between the grating148and the mating surface136while also extending over the opening132. The border portion156includes a thickness204suitable for being disposed between the mating surface136and the interior surfaces188(seeFIG.4C) of the grating148. As will be appreciated, placing the border portion156into the contact with the interior surfaces188ensures a space for the filter medium140is disposed between the base144and the grating148.

Moreover, the border portion156includes corner portions208that are configured to align with the corner portions180of the grating148. A through-hole212is disposed in each of the corner portions208and concentrically aligned with a corresponding through-hole176in each corner portion180of the grating148. It is contemplated that each of the through-holes212is configured to allow passage of a hardware fastener, such as a screw or bolt, into a hole184disposed in the mating surface136of the air filter box104. Thus, during fastening the air filter precleaner100onto the air filter box104, the hardware fasteners may be inserted through each pair of aligned through-holes176,212and then threadably engaged with the holes184disposed in the mating surface136of the air filter box104.

FIG.2illustrates an exploded isometric view of an exemplary embodiment of an air filter precleaner220that is configured to be coupled with an aircharger air intake system222comprising an air filter box224configured to couple a cone-shaped air filter108to an air intake of an engine. The air filter box224is similar to the air filter box104, shown inFIG.1, with the exception that the air filter box224is configured for use with a turbo-diesel engine and thus has a different shape than the air filter box104. Like the air filter box104, the air filter box224comprises multiple sidewalls112, a floor114, and a mount wall116that define an interior228of the air filter box224that houses the air filter108. The air filter box224generally supports the air filter108and provides an interface between the air filter108and the air intake of the engine by way of an intake tube124that may be coupled to the engine by way of an adapter128. Details pertaining to the walls112,116and the floor114, as well as coupling the air filter108and the air intake of the engine, are discussed in connection with the air filter box104shown inFIG.1. Further, like the air filter box104, the air filter box224generally is comprised of a rigid material that is sufficiently durable and temperature resistant to retain its configuration during installation and operation when coupled with the air intake of the engine.

As shown inFIG.2, the air filter box224includes an opening232to the interior228that is bordered by a flat mating surface236upon which the air filter precleaner220may be installed. As disclosed herein, the opening232facilitates installing and removing the air filter108from the interior228of the air filter box224, as needed. For example, once the air filter108is dirty, the air filter may be removed from the air filter box224, washed and dried, and then installed again into the air filter box224. In some embodiments, the air filter108may be treated with a filter oil composition that enhances the filtration properties of the air filter108.

In the embodiment illustrated inFIG.2, the air filter precleaner220includes a filter medium240disposed between a base244and a grating248that are configured to be fastened over the opening232of the air filter box224. The air filter precleaner220is similar to the air filter precleaner100, shown inFIG.1, with the exception that the air filter precleaner220has a shape and a size configured to cover the opening232of the air filter box224. As such, the filter medium240is configured to remove particulate matter from an airstream entering the air filter box224through the opening232. In some embodiments, the filter material240comprises a reticulated polyester urethane foam. The base244includes a grate252surrounded by a border portion256that are configured to support the filter medium240in a sheet configuration, such that the airstream passes through the filter medium240before entering the interior228of the air filter box224. The grating248includes a screen portion260surrounded by a frame264that is configured to be fastened onto the air filter box224. The screen portion260comprises a shaped lattice configured to allow an inflowing airstream to pass through the filter medium240before entering the air filter box224.

FIGS.6A through6Eillustrate an exemplary embodiment of the grating248that is configured to be implemented in the air filter precleaner220as shown inFIG.2. The grating248is a rigid member configured to couple the base244and the filter medium240onto the air filter box224, as well as to provide protection to the filter medium240from nearby components within the engine bay. As mentioned above, the grating248comprises a screen portion260surround by a frame264that is configured to be fastened onto the air filter box224. As best shown inFIG.6A, the screen portion260comprises a shaped lattice that is configured to direct an inflowing airstream through the filter medium240before entering the interior228of the air filter box224. In the illustrated embodiment ofFIGS.6A through6E, the screen portion260comprises a multiplicity of hexagon shaped openings268in the grating248. It should be understood, however, that the openings268may include any of various shapes that are suitable for tessellating the screen portion260, without limitation.

It will be recognized that the grating248is similar to the grating148, shown inFIGS.4A-4C, with the exception that the grating148includes a shape and a size suitable for fastening the base244and the filter medium240over the opening232of the air filter box224. Accordingly, the frame264generally includes a perimeter shape that is substantially similar to the shape of the mating surface236of the air filter box224. As best shown inFIGS.6C and6E, the frame264includes a peripheral lip272that is configured to extend over an exterior edge of the filter medium240and the base244, such that the peripheral lip272contacts the mating surface236surrounding the opening232. Further, a through-hole276disposed in each of one or more corner portions280comprising the frame264is configured to facilitate fastening the grating248onto the air filter box224. To this end, each of the through-holes276is configured to allow passage of a hardware fastener, such as a screw or bolt, into a hole184disposed in the mating surface236of the air filter box224. In the illustrated embodiment shown inFIG.6D, the through-holes276include a counterbore278configured to position a head portion of the hardware fastener below an exterior surface of the grating248.

As best shown inFIG.6C, an interior ledge288is disposed adjacent to the peripheral lip272and is configured to contact the border portion256of the base244. The interior ledge288is configured to ensure that a space suitable for the filter medium240is disposed between the base244and the screen portion260once the peripheral lip272contacts the mating surface236. Accordingly, the filter medium240includes edges292and corner portions294(seeFIG.11A) that are configured to allow the filter medium240to be positioned adjacent to the interior ledge288. Further, the filter medium240preferably includes a thickness296(seeFIG.11B) that is suitable for being disposed within the space surrounded by the screen portion260, the base244, and the interior ledge288.

FIGS.7A through7Cillustrate plan views of an exemplary embodiment of the base244that may be implemented in the air filter precleaner200shown inFIG.2. The base244is similar to the base144, shown inFIG.1, with the exception that the base244has a shape and a size configured specifically to cover the opening232of the air filter box224. The base244generally is a rigid member comprising a grate252surrounded by a border portion256having a shape and a size suitable for being positioned within the confines of the peripheral lip272of the grating248, as described above. The grate252is configured to support the filter medium240in a flat, sheet configuration between the base244and the grating248, such that an inflowing airstream passes through the filter medium240before entering through the opening232into the interior228of the air filter box224. As best shown inFIGS.7A and7C, the grate252comprises a framework of perpendicular elongate members300that are arranged to support the filter medium240in the sheet configuration.

The border portion256is configured to be surrounded by the peripheral lip272of the grating248while being placed in direct contact with the mating surface236of the air filter box224. As such, the border portion256includes a shape and a size suitable for being inserted within the confines of the peripheral lip272. Further, the border portion256includes a thickness304suitable for being disposed between the mating surface236and the interior ledge288(seeFIG.6E) of the grating248while also allowing the peripheral lip272to contact the mating surface236. As will be appreciated, placing the border portion256into the contact with the interior ledge288provides a space for the filter medium240is disposed between the base244and the screen portion260of the grating248. As discussed above, the space between the base244and the screen portion260preferably accommodates the thickness296of the filter medium240.

With continuing reference toFIGS.7A through7C, the border portion256includes corner portions308that are configured to align with the corner portions280of the grating248. A through-hole312is disposed in each of the corner portions308and concentrically aligned with a corresponding through-hole276in each corner portion280of the grating248. It is contemplated that each of the through-holes312is configured to allow passage of a hardware fastener, such as a screw or bolt, into a hole184disposed in the mating surface236of the air filter box224. During fastening the air filter precleaner200onto the air filter box224, therefore, the hardware fasteners may be inserted through each pair of aligned through-holes276,312and then threadably engaged with the holes184disposed in the mating surface236of the air filter box224.

Turning now toFIG.3, an exploded isometric view of an exemplary embodiment of an air filter precleaner320is illustrated. The air filter precleaner320is configured to be coupled with an aircharger air intake system322comprising an air filter box324configured to couple a cone-shaped air filter108(seeFIGS.1-2) to an air intake of an engine. The air filter box324is similar to the air filter box104, shown inFIG.1, with the exception that the air filter box324is configured for use with a turbo-equipped engine and thus has a different shape than the air filter box104. Like the air filter box104, the air filter box324comprises multiple sidewalls112, a floor114, and a mount wall116that define an interior328of the air filter box324that houses the air filter108. The air filter box324generally supports the air filter108and provides an interface between the air filter108and the air intake of the engine by way of an intake tube124that may be coupled to the engine by way of one or more suitable adapters. Details pertaining to the walls112,116and the floor114, as well as coupling the air filter108and the air intake of the engine, are discussed in connection with the air filter box104shown inFIG.1. Further, like the air filter box104, the air filter box324generally is comprised of a rigid material that is sufficiently durable and temperature resistant to retain its configuration during installation and operation when coupled with the air intake of the engine.

With continuing reference toFIG.3, the air filter precleaner320includes a filter medium340disposed between a base344and a grating348that are configured to be fastened onto a flat mating surface336bordering an opening332to the interior328of the air filter box324. The air filter precleaner320is similar to the air filter precleaner100, shown inFIG.1, with the exception that the air filter precleaner320has a shape and a size configured to cover the opening332of the air filter box324. The filter medium340is configured to remove particulate matter from an airstream entering the air filter box324through the opening332. It is contemplated that, in some embodiments, the filter material340comprises a reticulated polyester urethane foam. The base344includes a grate352surrounded by a border portion356that are configured to support the filter medium340in a sheet configuration, such that the airstream passes through the filter medium340before entering the interior328of the air filter box324. The grating348includes a screen portion360surrounded by a frame364that is configured to be fastened onto the air filter box324. The screen portion360comprises a shaped lattice configured to direct an inflowing airstream to through the filter medium340before entering the air filter box324.

FIGS.8A through8Eillustrate an exemplary embodiment of the grating348that may be implemented in the air filter precleaner320ofFIG.3. The grating348is a rigid member configured to couple the base344and the filter medium340onto the air filter box324, as well as to provide protection to the filter medium340from nearby components within the engine bay. As mentioned above, the grating348comprises a screen portion360surround by a frame364that is configured to be fastened onto the air filter box324. As best shown inFIG.8A, the screen portion360comprises a shaped lattice that is configured to direct the inflowing airstream through the filter medium340before entering the interior328of the air filter box324. In the illustrated embodiment ofFIGS.8A through8E, the screen portion360comprises a multiplicity of hexagon shaped openings368in the grating348. It is contemplated, however, that the openings368may include any of various shapes that are suitable for tessellating the screen portion360, without limitation.

As will be appreciated, the grating348is similar to the grating148, shown inFIGS.4A-4C, with the exception that the grating348includes a shape and a size suitable for fastening the base344and the filter medium340over the opening332of the air filter box324. As such, the frame364includes a perimeter shape that is substantially similar to the shape of the mating surface336disposed around the opening332of the air filter box324. As best shown inFIGS.8C and8E, the frame364includes a peripheral lip372that is configured to extend over an exterior edge of the filter medium340and the base344, such that the peripheral lip372contacts the mating surface336once installed onto the air filter box324. Further, a through-hole376disposed in each of one or more corner portions380comprising the frame364is configured to facilitate fastening the grating348onto the air filter box324. To this end, each of the through-holes376is configured to allow passage of a hardware fastener, such as a screw or bolt, into a counterbored hole384disposed in the mating surface336of the air filter box324. In the illustrated embodiment shown inFIG.8E, the through-holes376include a counterbore378configured to position a head portion of the hardware fastener below an exterior surface of the grating348.

As shown inFIGS.8C and8E, a cylindrical ridge388defining each of the through-holes376extends below the screen portion260parallel to the peripheral lip372. Each of the cylindrical ridges388is configured to extend through a through-hole390(seeFIG.12A) disposed in the filter medium340and contact the border portion356of the base344. The cylindrical ridges288are configured to ensure that a space suitable for the filter medium340is disposed between the base344and the screen portion360once the peripheral lip372contacts the mating surface336. Accordingly, the filter medium340includes edges392and corner portions394(seeFIG.12A) that are configured to allow the filter medium340to be positioned adjacent to the peripheral lip272and the cylindrical ridges388. Further, the filter medium340preferably includes a thickness396(seeFIG.12B) that is suitable for being disposed within the space surrounded by the screen portion360, the base344, and the peripheral lip372.

FIGS.9A through9Dillustrate plan views of an exemplary embodiment of the base344that is suitable for being implemented in the air filter precleaner320shown inFIG.3. The base344is similar to the base144, shown inFIG.1, with the exception that the base344has a shape and a size configured specifically to cover the opening332of the air filter box324. The base344is a generally rigid member comprising a grate352surrounded by a border portion356having a shape and a size suitable for being positioned within the confines of the peripheral lip372of the grating348, as described above. The grate352is configured to support the filter medium340in a flat, sheet configuration between the base344and the grating348, such that the inflowing airstream passes through the filter medium340before entering air filter box324. As shown inFIGS.9A and9C, the grate352comprises a framework of perpendicular elongate members400that are arranged to support the filter medium340in the sheet configuration. It will be appreciated that the elongate members400are substantially similar to the elongate members152,252respectively illustrated inFIGS.5A and7A.

The border portion356is configured to be surrounded by the peripheral lip372of the grating348while being placed in direct contact with the mating surface336of the air filter box324. To this end, the border portion356includes a shape and a size suitable for being inserted within the confines of the peripheral lip372. Further, the border portion356includes a thickness404suitable for being disposed between the mating surface336and the cylindrical ridges388(seeFIG.8E) of the grating348while also allowing the peripheral lip372to contact the mating surface336. As will be appreciated, placing the border portion356into the contact with the cylindrical ridges388provides a space for the filter medium340to be disposed between the base344and the screen portion360of the grating348. As discussed herein, the space between the base344and the screen portion360preferably accommodates the thickness396(seeFIG.12B) of the filter medium340.

With continuing reference toFIGS.9A through9C, the border portion356includes corner portions408that are configured to align with the corner portions380of the grating348. A through-hole412is disposed in each of the corner portions408and configured to be concentrically aligned with a corresponding through-hole376in each corner portion380of the grating348. It is contemplated that each of the through-holes412is configured to allow passage of a hardware fastener, such as a screw or bolt, into a counterbored hole384disposed in the mating surface336of the air filter box324. Further, the border portion356includes a thicker portion416surrounding each of the through-holes412, as shown inFIG.9D. The thicker portions416are configured to extend into the counterbored holes384when the base344is placed into contact with the mating surface336. As will be appreciated, extending the thicker portions416into the counterbored holes384serves to keep the through-holes412advantageously aligned with the counterbored holes384in the mating surface336. During fastening the air filter precleaner320onto the air filter box324, therefore, the hardware fasteners may be inserted through each pair of aligned through-holes376,412and then threadably engaged with the counterbored holes384disposed in the mating surface336of the air filter box324.

While the invention has been described in terms of particular variations and illustrative figures, those of ordinary skill in the art will recognize that the invention is not limited to the variations or figures described. In addition, where methods and steps described above indicate certain events occurring in certain order, those of ordinary skill in the art will recognize that the ordering of certain steps may be modified and that such modifications are in accordance with the variations of the invention. Additionally, certain of the steps may be performed concurrently in a parallel process when possible, as well as performed sequentially as described above. To the extent there are variations of the invention, which are within the spirit of the disclosure or equivalent to the inventions found in the claims, it is the intent that this patent will cover those variations as well. Therefore, the present disclosure is to be understood as not limited by the specific embodiments described herein, but only by scope of the appended claims.