Claims:We Claim:
1. A multistage air filter assembly (101) comprising:
one or more separator (104); and
one or more air filter (103) being configured to accommodate one or more filter elements (202);
wherein said filter elements (202) includes one or more paper filter element (202B), and one or more foam filter element (202A).

2. The multistage air filter assembly (101) as claimed in claim 1, wherein said air filter (103) comprises one or more perforated tube (401) surrounded by said paper filter element (202B).

3. The multistage air filter assembly (101) as claimed in claim 1, wherein said one or more paper filter element (202B) and one or more foam filter element (202A) being configured to have substantially cylinder structure.

4. The multistage air filter assembly (101) as claimed in claim 1, wherein said one or more paper filter element (202B) and one or more foam filter element (202A) being substantially concentric to each other.

5. The multistage air filter assembly (101) as claimed in claim 1, wherein said foam filter element (202A) being wrapped around said paper filter element (202B) such that both being substantially concentric to said perforated tube (401).

6. The multistage air filter assembly (101) as claimed in claim 1, wherein said one or more separator (104) being communicatively connected and supported by said air filter (103).

7. The multistage air filter assembly (101) as claimed in claim 1, wherein said one or more separator (104) being configured to receive atmospheric air through an air tube inlet (106).

8. The multistage air filter assembly (101) as claimed in claim 7, wherein one end of said air inlet tube (106) being configured to have a tangential engagement with a portion of said separator (104) to create a vortex flow of atmospheric air in said separator (104).

9. The multistage air filter assembly (101) as claimed in claim 7, wherein said air inlet tube (106) is formed from an organic polymer having high molecular mass and being configured to have a predetermined contour.

10. A method of atmospheric air filtration including steps of:
passing atmospheric air under pressure through a separator (104) (Step S101); and
circulating the atmospheric air passed from said separator (104) through one or more filter elements (202) of an air filter (103) (Step S102).

11. The method of atmospheric air filtration as claimed in claim 10, wherein said filtration through one or more filter elements (202) includes first filter being a foam filter element (202A) followed by a paper filter element (202B) before air being supplied to a combustion chamber.

12. A multistage air filter assembly for a vehicle comprising
one or more separator (104), said separator (104) being configured to receive atmospheric air from an air inlet tube (106); and
one or more air filter (103) attached to a chassis frame structure (102), said air filter (103) being configured to accommodate one or more filter elements (202),
wherein said filter elements (202) includes one or more paper filter elements (202B) and one or more foam filter element (202A),
wherein said foam filter element (202A) is wrapped around said paper filter element (202B).
, Description:TECHNICAL FIELD
[0001] The present subject matter relates to an air filter assembly. More particularly, the present subject matter is a patent of addition to a subject matter disclosed in the patent application number 201641011586. The present subject matter offers improvement over the subject matter as claimed in the aforementioned patent application.

BACKGROUND
[0002] Generally, an internal combustion engine comprises a cylinder bore where the combustion occurs to provide the needed power for the forward motion of a vehicle. The internal combustion (IC) engine, among other components, has a cylinder on top of which a cylinder head is mounted, and receives a reciprocating piston from the bottom. On the combustion of the air-fuel mixture, the piston transfers the energy generated during combustion to a crankshaft through a connecting rod thereby driving the crankshaft. In this way, the reciprocating motion of the piston is converted to the rotary motion of the crankshaft. The crankshaft rotation then in turn powers the vehicle. For an internal combustion engine to generate desired power and torque, air intake system plays a significant role. The intake system consists of an air cleaner, a carburetor and a pipe intake. The function of air cleaner is to supply clean air to engine at all operating conditions. The air cleaner is further divided into a pre-filter and post filter area with help of a suitable filtering media. In a three-wheeled vehicle where engine is disposed in rear portion, a cabin space is formed between rear seat and rear portion. The air cleaner is generally placed inside this cabin space. The air inlet to the air cleaner is provided with a grill in order to get rid of bigger dust particles and water.
[0003] The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The present invention is described with reference to an exemplary embodiment of a light weight commercial vehicle with the accompanying figures. The same numbers are used throughout the drawings to reference like features and components. Further, the inventive features of the invention are set forth in the appended claims.
[0005] Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. It should be appreciated that the following figures may not be drawn to scale.
[0006] Descriptions of certain details and implementations follow, including a description of the figures, which may depict some or all of the embodiments described below, as well as a discussion of other potential embodiments or implementations of the inventive concepts presented herein. An overview of embodiments of the invention is provided below, followed by a more detailed description with reference to the drawings.
[0007] Figure 1 illustrates a rear side perspective view of a multistage air filter assembly (101) for vehicle (100) as per embodiment, in accordance with one example of the present subject matter.
[0008] Figure 2 illustrates an exploded view of the multistage air filter assembly (101) wherein few parts are omitted from the figure as per embodiment, in accordance with one example of the present subject matter.
[0009] Figure 3 illustrates a rear view and a side cut section view of the multi stage air filter assembly (101) across A-A’ axis, where few parts are omitted from the figure as per embodiment, in accordance with one example of the present subject matter.
[00010] Figure 4 illustrates a side view and a rear side cut section view of the multistage air filter assembly (101) across B-B’ axis where few parts are omitted from the figure, as per embodiment, in accordance with one example of the present subject matter.
[00011] Figure 5a illustrates top perspective cut section view of the multistage air filter assembly (101) as per embodiment, in accordance with one example of the present subject matter.
[00012] Figure 5b illustrates a flowchart depicting flow of air through multistage filter assembly as per embodiment, in accordance with one example of the present subject matter.

DETAILED DESCRIPTION
[00013] Various features and embodiments of the present subject matter here will be discernible from the following further description thereof, set out hereunder.
[00014] Engine power is a function of torque and speed. In order to increase the power of the engine, it is essential to increase torque or speed, or both. Further, torque is a function of pressure, area of the piston, and engine speed (rev/min). Therefore, to increase the torque, it is necessary to increase the area of the piston and/or engine speed or to increase pressure. However, an increase in the area of piston and engine speed increase engine displacement. Therefore, one of the ways to increase torque without an increase in the engine size is by increasing air intake pressure level i.e. eventually enhancing combustion efficiency. The intake pressure can be raised if a same rate of intake airflow can be maintained even at higher crankshaft speeds.
[00015] Therefore, airflow is an essential parameter because the engines make power by extracting heat from air fuel mixture flow. Typically, the engine first pump the air in, add fuel and burn it, convert the heat into useful work. Therefore, a certain amount of air has to be moved in a very short period of time.
[00016] Typically, an induction system comprising of air filter which acts as a reservoir to supply purified air through a filter element as well as boost the airflow at certain speed ranges. The filter element is replaced periodically as they get clogged and thereby inhibit the flow of air into the engine. However, it is observed that in dusty environments within certain speed ranges the air filter is not able to supply necessary air and act as the most restrictive part of the induction system. Therefore, the piston would not draw in as much air as required leading to undesirable combustion efficiency and low output torque. However, the air inside the combustion chamber would expand to fill a cylinder of the engine, but at reduced pressure and consequently, less power is produced from it. Further, the air available to the engine after passing through the filter element potentially includes fine dust particles. Importantly, fine dust particles can cause substantial damage to the internal components like piston rings, piston, and cylinder lining of the engine. Once the dust particles enter the engine combustion region, all the parts subjected to continuous lubrication get undesirably exposed to the dust. The dust particles can enter an oil film, it can form a direct link between sliding surfaces which can result in undesirable wear effect i.e. scratching of the surface as the particle is dragged and rolled across the surfaces. Moreover, fine dust particles in between two surface changes the loading of the surface from an even distribution to a load concentrated on the dust particles with a tremendous increase in the pressure at local points. The increase in pressure causes undesirable micro-deformation of the surface, which results in metal fatigue and the breaking up of the surface i.e. metal wear. Furthermore, increased wear increases the oil consumption rate leading to frequent maintenance or service. Importantly, if the oil level goes below the prescribed limit then internal parts can excessively rub against each other, creating an enormous amount of heat from the undesirable friction and this phenomenon can lead to engine seizure.
[00017] In order to address the above-said problem, various strategies are adopted to trap fine dust particles in the air. It is known in the art to provide a stack of paper filter elements of varying micron levels. However, the use of a stack of paper filter elements of varying micron levels is disadvantageous because it requires a large casing size being configured to accommodate paper filter elements as well as increases cost of the air filter system. Additionally, to support such a large casing a rigid support structure is required which increases the overall size of the induction system. The increase in the size of the induction system for a compact vehicle is undesirable owing to its adverse impact on layout packaging, the weight of the vehicle, mass distribution as well as cost.
[00018] Moreover, it is observed that the paper filter element is very sensitive to humid conditions. Exposure to moisture or humidity reduces the efficiency of the paper filter element and it ability to trap fine sand or dust particles. Therefore, it is always a challenge for design engineers to develop a compact induction system configured to meet the power requirement of the engine under different engine operating conditions as well as in extreme weather conditions like a sandy environment. Accordingly, there is a need for an effective and compact air filtration system for a vehicle which overcomes all the above problems and other problems of the known art.
[00019] To this end, it is an object of the present invention to provide a compact, durable and efficient air filter assembly which effectively removes both the liquid and solid particulates from the atmospheric air before it is supplied to the combustion chamber (s).
[00020] It is another object of the present invention is to provide an air filter assembly that can effectively work to deliver filtered air to the engine in challenging operating conditions, such as sandy environment, heavy rainfall regions while still being easy for service without necessitating frequent service / maintenance.
[00021] According to the present subject matter, to attain the above-mentioned objectives, a first characteristic of the present invention is a multistage air filter assembly comprising one or more separator; and one or more air filter being configured to accommodate one or more filter elements. The filter elements include one or more paper filter elements, and one or more foam filter elements.
[00022] In addition to the first characteristic, a second characteristic of the present invention is multistage air filter assembly, wherein said air filter comprises one or more perforated tube surrounded by said paper filter element.
[00023] In addition to the first characteristic, a third characteristic of the present invention is the multistage air filter assembly, wherein said one or more paper filter elements and one or more foam filter element being configured to have substantially cylinder structure.
[00024] In addition to the first characteristic, a fourth characteristic of the present invention is the multistage air filter assembly as claimed in claim 1, wherein said one or more paper filter elements and one or more foam filter element being substantially concentric to each other.
[00025] In addition to the first characteristic, a fifth characteristic of the present invention is the multistage air filter assembly, wherein said foam filter element being wrapped around said paper filter element such that both being substantially concentric to said perforated tube.
[00026] In addition to the first characteristic, a sixth characteristic of the present invention is the multistage air filter assembly, wherein said one or more separator (104) being communicatively connected and supported by said air filter.
[00027] In addition to the first characteristic, a seventh characteristic of the present invention is the multistage air filter assembly, wherein said one or more separator being configured to receive atmospheric air through an air tube inlet.
[00028] In addition to the first characteristic and seventh characteristic of the present invention, an eighth characteristic of the present invention is the multistage air filter assembly, wherein one end of said air inlet tube being configured to have a tangential engagement with a portion of said separator to create a vortex flow of atmospheric air in said separator.
[00029] In addition to the first characteristic and seventh characteristic of the present invention, an ninth characteristic of the present invention is the multistage air filter assembly, wherein said air inlet tube is formed from an organic polymer having high molecular mass and being configured to follow a predetermined contour.
[00030] A tenth characteristic of the present invention is a method of atmospheric air filtration including steps of: at step (S101), passing atmospheric air under pressure through a separator; and at step (S102) circulating the atmospheric air passed from said separator through one or more filter elements of an air filter.
[00031] In addition to the tenth characteristic of the present invention, an eleventh characteristic of the present invention is method of atmospheric air filtration wherein said filtration through one or more filter elements (202) includes first filter being a foam filter element (202A) followed by a paper filter element (202B) before air being supplied to a combustion chamber.
[00032] A twelfth characteristic of the present invention is a multistage air filter assembly for a vehicle comprising one or more separator, said separator being configured to receive atmospheric air from an air inlet tube; one or more air filter attached to a chassis frame structure, said air filter being configured to accommodate one or more filter elements, said filter elements includes one or more paper filter elements and one or more foam filter elements, wherein said foam filter element is wrapped around said paper filter element.
[00033] The present subject matter is further described with reference to accompanying figures. It should be noted that the description and figures merely illustrate principles of the present subject matter. Various arrangements may be devised that, although not explicitly described or shown herein, encompass the principles of the present subject matter. Moreover, all statements herein reciting principles, aspects, and examples of the present subject matter, as well as specific examples thereof, are intended to encompass equivalents thereof.
[00034] The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. As such, it is contemplated that various alternate embodiments and/or modifications to the present disclosure, whether explicitly described or implied herein, are possible in light of the disclosure. Having thus described embodiments of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made in form and detail without departing from the scope of the present disclosure. Thus, the present disclosure is limited only by the claims.
[00035] In the foregoing specification, the disclosure has been described with reference to specific embodiments. However, as one skilled in the art will appreciate, various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of the disclosure. Accordingly, this description is to be considered as illustrative and is for the purpose of teaching those skilled in the art the manner of making and using various embodiments of the disclosure. It is to be understood that the forms of disclosure herein shown and described are to be taken as representative embodiments. Equivalent elements, materials, processes or steps may be substituted for those representatively illustrated and described herein. Moreover, certain features of the disclosure may be utilized independently of the use of other features, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural.
[00036] Further, various embodiments disclosed herein are to be taken in the illustrative and explanatory sense, and should in no way be construed as limiting of the present disclosure. All joinder references (e.g., attached, affixed, coupled, connected, etc.) are only used to aid the reader's understanding of the present disclosure, and may not create limitations, particularly as to the position, orientation, or use of the systems and/or methods disclosed herein. Therefore, joinder references, if any, are to be construed broadly. Moreover, such joinder references do not necessarily infer that two elements are directly connected to each other.
[00037] Additionally, all numerical terms, such as, but not limited to, “first”, “second”, “third”, “primary”, “secondary”, “main” or any other ordinary and/or numerical terms, should also be taken only as identifiers, to assist the reader's understanding of the various elements, embodiments, variations and/or modifications of the present disclosure, and may not create any limitations, particularly as to the order, or preference, of any element, embodiment, variation and/or modification relative to, or over, another element, embodiment, variation and/or modification.
[00038] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application. Additionally, any signal hatches in the drawings/figures should be considered only as exemplary, and not limiting, unless otherwise specifically specified.
[00039] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[00040] Figure 1 illustrates a rear side perspective view of a multistage air filter assembly (101) for a vehicle (100) as per embodiment, in accordance with one example of the present subject matter. A multistage air filter assembly (101) is mounted to a portion of a chassis frame structure (102). As per the preferred embodiment, the multi stage filter assembly (101) is arranged near a rear end portion of the vehicle (100). The multistage air filter assembly (101) includes an air filter (103) communicatively connected to a separator (104). The air filter (103) is attached to the chassis frame structure (102) using attachment means (105). The separator (104) is configured to receive fresh air through an air inlet tube (106). The air inlet tube (106) being formed from an organic polymer having high molecular mass and is configured to have a predetermined contour. The predetermined contour includes a multi-curved profile. In illustrated embodiment, the air inlet tube (106) has a substantially S-shaped profile. The S-shape profile is configured to attenuate the noise generated due to suction of atmospheric air in the multistage air filter assembly (101) and thereby achieve silent operation. Air is sucked in the separator (104) using atmospheric pressure which subsequently combines with the vacuum created in the combustion chamber, said vacuum being created by the descending motion of piston towards bottom dead center (BDC) without the need for external pumping means. More specifically, one end of said air inlet tube (106) being configured to have a tangential engagement with a said separator (104) to create a vortex flow of atmospheric air inside the separator (104). The other end of the air inlet tube (106) is attached to an air inlet grill (107). The air inlet grill (107) housed in a side cover (108) of said vehicle (100). The air inlet grill (107) prevents stone particles from entry inside the multistage air filter assembly (101).
[00041] Figure 2 illustrates a partial exploded perspective view of the multistage air filter assembly (101) wherein a few parts are omitted from the figure as per embodiment, in accordance with one example of the present subject matter. The air filter (103) includes a housing (201), and a housing cover (203). The housing (201) is configured to accommodate one or more filter elements (202). The axial open end face of the housing (201) is sealed by the housing cover (203). The housing cover (203) is detachably attached to the housing (201) to access the filter elements (202). As per the preferred embodiment, the filter elements (202) are configured to have a substantially cylindrical shape. The filter elements (202) include one or more paper filter elements (202B) and one or more foam filter elements (202A). The separator (104) is detachably attached to said air filter (103) using attachment means (204).
[00042] Figure 3 illustrates a rear view and a side cut section view of the multi stage air filter assembly (101) across A-A’ axis, where few parts are omitted from the figure as per embodiment, in accordance with one example of the present subject matter. The separator (104) comprises a separator housing (301) that is configured to separate liquid and heavy particulate matters from atmospheric air. The separator housing (301) includes an upper half portion (301A) and a lower half portion (301B). The lower half portion (301B) is configured to have a truncated cone profile provided with a one way valve (301BA) at a lowermost point. During operation, the one way valve (301BA) flushes the trapped moisture or dirt particles out of the separator (104). The upper half portion (301A) is configured to have an inlet portion (301AA) and outlet portion (301AB). The inlet portion (301AA) is designed to ensure the tangential engagement of the tube inlet (106) with the separator (104) to create a vortex flow of atmospheric air enabling separation of liquid and heavy particulate matters. Further, the outlet portion (301AB) is detachably attached to the air filter (103).
[00043] Figure 4 illustrates a side view and a rear side cut section view of the multistage air filter assembly (101) across a B-B’ axis where few parts are omitted from the figure, as per embodiment, in accordance with one example of the present subject matter. The housing (201) includes a perforated tube (401) surrounded by said paper filter element (202B). As per preferred embodiment, said paper filter element (202B) and foam filter element (202A) are substantially concentric to perforated tube (401) such that foam filter element (202A) wraps around paper filter element (202B).
[00044] Figure 5a illustrates a top perspective cut section view of the multistage filter assembly (101) as per embodiment, in accordance with one example of the present subject matter. Figure 5b illustrates a flowchart depicting flow of air through multistage filter assembly as per embodiment, in accordance with one example of the present subject matter. For sake of brevity, figure 5a and 5b will be discussed together. As per preferred embodiment, the multistage filter assembly (101) comprises of multi-stage filtration process wherein flow of air is shown by arrow marks in illustration. At step (S101), the atmospheric air enters the separator (104) through the air intake tube (106) in the direction of arrows. After entering the separator (104), the atmospheric air rotates at high velocity leading to the separation of liquid and heavy dirt particles by centrifugal force and vortex in the separator . Therefore, it is possible to remove the greatest percentage of a particular matter at the end of the first step (S101) by means of the separator (104). At step (S102), the air enters a pre-filter area (501) of the air filter (103), where it passes through the foam filter element (202A) wrapped around the paper filter element (202B) in the direction of arrows. The foam filter element (202A), filters the dust and other undesired constituents in the air. Subsequent to that, the air passes through the paper filter element (202B) in the direction of arrows towards the inner region of the paper filter element (202B). The paper filter element (202B) is configured to have a predetermined pore size which allows air to pass and filters the fine dust particles. Therefore, at the end of step (S102) purified air reaches the post-filter area (502) through the perforated tube (401) in the direction of arrows. From, the post-filter area (502) the filtered air directed towards an engine (not shown).
[00045] According to the above architecture, one of the primary efficacies of the present invention is a compact multistage air filtration assembly which has different stages of filtration configured in a small space to trap fine dust and particles, thereby improving the quality of air inducted in the engine which enhances the durability of internal parts.
[00046] According to the above architecture, one of the primary efficacies of the present invention is the cost-effective solution to improve the efficiency of the engine without changing the engine design because the multistage filter assembly delivers necessary air without external pumping means through a three-stage filtration process in all extreme weather conditions, with less periodic maintenance of filter elements.
[00047] According to the above architecture, one of the primary efficacies of the present invention is that it improves the durability of filter elements by trapping liquid and heavy dirt particles before entering into the air filter.
[00048] The above-described embodiments, and particularly any “preferred” embodiments, are possible examples of implementations and merely set forth for a clear understanding of the principles of the invention. For example, multistage air filtration system can be implemented in industries like textile unit to deliver purified and dehumidified air. It will be apparent to those skilled in the art that changes in form, connection, and detail may be made therein without departing from the spirit and scope of the invention. Like the foam filter element can be disposed in a separate housing configured to filter the air.

List of References:

100 Vehicle
101 Multistage air filter assembly
102 Chassis frame structure
103 Air filter
104 Separator
105 Attachment means
106 Air inlet tube
107 Air inlet grill
108 Side cover
201 Housing
202 Filter elements
202A Foam filter element
202B Paper filter element
203 Housing cover
204 Attachment means
301 Separator housing
301A Upper half portion
301AA Inlet portion
301AB Outlet portion
301B Lower half portion
301BA One way valve
401 Perforated tube
501 Pre filter area
502 Post filter area