Filter module

Abstract

The invention relates to a filter module (1) comprising a housing (2) and a particle filter (3). The particle filter (3) is arranged in the housing (2) and divides the housing (2) into a raw side (2a) and a clean side (2b). The filter module (1) also has a bypass (5). The bypass (5) connects the raw side (2a) and the clean side (2b) around the particle filter (3) within the housing (2). The invention also relates to an air conditioning system with the filter module (1).

Description

[0001] The invention relates to a filter module for an air conditioning system of a vehicle for filtering air, comprising a housing and a particle filter according to the preamble of claim 1. The invention also relates to an air conditioning system with the filter module.

[0002] A filter module can be used, for example, in a vehicle's air conditioning system. A major challenge is achieving sufficient separation efficiency while minimizing pressure loss within the filter module. Current solutions always represent a compromise between the filter module's separation efficiency and the pressure loss within it. As a result, the separation efficiency is often insufficient over the entire lifespan of the filter module, especially at minimum flow rates through the filter module and, consequently, through the air conditioning system.

[0003] The object of the invention is therefore to provide an improved or at least alternative embodiment for a filter module of the generic type, in which the described disadvantages are overcome.

[0004] This problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments are the subject matter of the dependent claims.

[0005] The present invention is based on the general concept of implementing water separation and pre-filtration or a pre-filter stage in a filter module with a bypass, thereby improving particle separation without increasing the pressure drop in the filter module and without critically reducing its service life. Furthermore, the solution should be as simple and cost-effective as possible; in particular, additional components – such as a filter bypass flap – should be avoided wherever possible.

[0006] The filter module according to the invention is designed for filtering air in a vehicle's air conditioning system. The filter module comprises a flow-through housing and a flow-through particulate filter. The particulate filter is arranged within the housing and divides the housing into a raw side and a clean side. The housing further comprises a flow-through inlet on the raw side and a flow-through outlet on the clean side. The inlet and outlet are connected in a way that allows flow through the particulate filter. According to the invention, the filter module includes a bypass, wherein the bypass within the housing connects the raw side and the clean side of the housing around the particulate filter, allowing flow through them.

[0007] The filter module according to the invention primarily concerns a pre-filter stage for a vehicle air conditioning system, or a water separation system with a particle filter for a vehicle air conditioning system. In the context of the present invention, the term "flowable" is used synonymously with the term "air can flow through it." The phrase "divides the housing into a clean side and a raw side" is used synonymously with the phrase "separates the housing, at least partially, into a raw side and a clean side." The phrase "raw side" is used here synonymously with the phrase "lying on the raw side" or "associated with the raw side." The phrase "clean side" is used here synonymously with the phrase "lying on the clean side" or "associated with the clean side."

[0008] The bypass formed within the housing of the filter module is continuous, thus permanently connecting the raw and clean sides of the housing. As air flows through the filter module, it is split on the raw side. Part of the air passes through the particulate filter, while the other part flows through the bypass to the clean side and on to the outlet. The air distribution, or rather the size of each portion, depends on the particulate filter's loading level. As the particulate filter becomes increasingly loaded, the air distribution adjusts automatically, as air seeks the path of least resistance. This ensures that the particulate filter is supplied with air as needed, and the maximum airflow rate through the filter module can be maintained at all times, regardless of the particulate filter's loading level.This also reduces the pressure loss in the filter module and, consequently, its contribution to the overall pressure loss in the air conditioning system. Furthermore, the bypass reduces the particulate filter's loading, thus increasing the filter module's service life.

[0009] The particulate filter can be, in particular, a flat – for example, pleated – particulate filter with a raw-side filter surface and a clean-side filter surface. The raw-side filter surface and the clean-side filter surface can, in particular, be arranged opposite each other. The particulate filter can have an adsorption layer on the raw-side filter surface. The particulate filter can, for example, be a coarse particulate filter or a fine particulate filter. The particulate filter can, in particular, have a flow-through filter material and a rigid frame or holder supporting the filter material. If the particulate filter is pleated, the filter material can be pleated and held in the frame or holder.

[0010] The housing can be made of plastic, for example. The housing can optionally include a bracket for positioning and holding the particulate filter. The bracket can be integrally formed with the housing. The inlet and / or outlet can be integrally formed with the housing, for example, in the form of a tubular nozzle.

[0011] The bypass can be formed, for example, by an area of ​​the housing that is not filled or is not filled by the particulate filter. In other words, the bypass can be formed, for example, by the particulate filter leaving a portion of the housing unfilled or not filling it. Advantageously, the particulate filter leaves a volume of air through the housing, perpendicular to a distance direction or perpendicular to a connecting line between the inlet and the outlet, in a region—preferably at the end—so that the bypass is formed in this unfilled area.

[0012] The bypass can be formed between the housing and the particulate filter, for example, in the form of a flow-through slot. The bypass can be arranged at a distance from the inlet and the outlet. The bypass can be formed adjacent to the particulate filter. The bypass and the particulate filter can lie in a common plane oriented transversely to a connecting line linking the inlet and the outlet. In particular, the bypass can be positioned transversely to the connecting line to the inlet and the outlet and arranged along the connecting line between the inlet and the outlet.

[0013] The cross-sectional area through which the bypass flows can be smaller, preferably several times smaller, than the cross-sectional area through which the particulate filter flows. The cross-sectional area through which the bypass flows can be designed, in particular, to ensure the highest possible particle separation efficiency in the particulate filter while maintaining a sufficient service life for the filter module. The cross-sectional area through which the bypass flows can also be designed, in particular, to ensure that the maximum permissible pressure drop of the filter system is not exceeded, even when the particulate filter is completely closed or fully loaded.

[0014] In one possible design of the filter module, the particulate filter can be designed so that air flows through it via the shortest path from the inlet to the outlet. This ensures that, regardless of the particulate filter's load, the proportion of air flowing through the bypass is minimized and the proportion of air flowing through – and filtered by – the particulate filter is always maximized.

[0015] The housing can, for example, incorporate a filter path. This filter path can connect the inlet and outlet, allowing airflow through the particulate filter, and can be at least partially straight. The inlet and outlet can be positioned opposite each other within the housing, and the particulate filter can be located between them. In other words, the particulate filter can be situated along a connecting line between the inlet and outlet, or it can intersect such a line. This allows the air flowing in through the inlet to directly impact the filter surface on the housing side, ensuring the shortest possible flow path through the particulate filter from the inlet to the outlet.

[0016] The particulate filter can have a raw-side filter surface facing the raw side and / or a clean-side filter surface facing the clean side. The clean-side filter surface can, for example, be located opposite the outlet and / or oriented perpendicular to a longitudinal center axis of the outlet. The raw-side filter surface can, for example, be located opposite the inlet. This allows the air flowing in through the inlet to directly impact the raw-side filter surface, and the flow through the particulate filter from the inlet to the outlet can occur at least partially via the shortest path. The raw-side filter surface can, for example, be oriented perpendicular to a longitudinal center axis of the inlet. By orienting the raw-side filter surface perpendicular to the longitudinal center axis of the inlet, or...Furthermore, the inlet-forming nozzle allows the airflow from the raw-side filter surface to occur at an angle of 90°, thereby maximizing the proportion of air flowing through the particle filter.

[0017] In one possible design of the filter module, the bypass from the inlet to the outlet can be configured so that air flows along the longest possible path. This ensures that, regardless of the particulate filter's load, the proportion of air flowing through the bypass is minimized and the proportion of air flowing through – and filtered by – the particulate filter is always maximized.

[0018] The housing can, for example, have a flow-through bypass channel, whereby the bypass channel connects the inlet and outlet via the bypass, thus bypassing the particulate filter. The bypass channel is advantageously siphon-like or U-shaped. The siphon-like bypass channel, in particular, prevents the air flowing in from the inlet from flowing directly to the outlet via the bypass instead of being directed to the particulate filter. The siphon-like bypass channel can also serve as a water separator, as described in more detail below.

[0019] A section of the bypass channel assigned to the raw side can, for example, be aligned parallel to a raw-side filter surface of the particulate filter facing the raw side. The portion of the air flowing through the bypass can thus be guided along the raw-side filter surface in the raw-side section of the bypass channel. Similarly, a clean-side section of the bypass channel assigned to the clean side can be aligned parallel to a clean-side filter surface of the particulate filter facing the clean side. The portion of the air flowing through the bypass can thus be guided along the clean-side filter surface in the clean-side section of the bypass channel. This allows the air flowing in from the inlet to first pass over the particulate filter, partially through the particulate filter, and then via the bypass to the outlet.In a properly oriented filter module, the section of the bypass channel facing the raw material can run downwards from the inlet to the bypass, and the section facing the clean material can run upwards from the bypass to the outlet. The bypass can be located below the particulate filter. Therefore, in a properly oriented filter module, the bypass channel can have a U-shape. The inlet and outlet can then be formed or arranged at opposite ends of the bypass channel on the housing.

[0020] In one possible configuration of the filter module, it can be provided that the filter module includes a water separator with a water barrier or impact surface for separating the water contained in the air and a water drainage channel. The water barrier can be formed by a raw-side filter surface of the particle filter facing the housing, and the water drainage channel can be formed on the raw side of the housing. The water drainage channel can extrude from the housing to the outside. The water contained in the incoming air can be separated on the raw side by the water barrier and directed out of the housing, for example, into a collection container, via the water drainage channel. In a filter module oriented for optimal operation, the water drainage channel can extrude downwards from the housing.The water drainage channel can be shaped particularly adjacent to the bypass. Advantageously, the aerosols contained in the air flowing into the inlet can be partially deflected from the airflow to the particle filter by their inertia, thereby increasing the separation efficiency of the filter module.

[0021] The invention also relates to an air conditioning system for a vehicle. The air conditioning system has a fresh air inlet for fresh air to flow into the system and a fresh air / recirculated air mixing point for mixing the recirculated air and the fresh air. The air conditioning system also has a filter module, which is located downstream of the fresh air inlet. The filter module is designed and shaped as described above. Furthermore, the air conditioning system has a filter element, which is located downstream of the fresh air / recirculated air mixing point.

[0022] The filter module is located downstream of the fresh air intake, enabling water separation and pre-filtration via a bypass. This improves particle separation without increasing the pressure drop within the filter module or significantly reducing its service life. The filter element is positioned downstream of the fresh air / recirculated air mixing point, providing additional filtration of the fresh air during fresh air operation and filtration of the recirculated air during recirculated air operation.

[0023] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0024] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0025] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0026] They show, each schematically Fig. 1 a sectional view of a filter module according to the invention; Fig. 2 a sectional view of the filter module according to the invention with indicated airflow; Fig. 3 a course of the pressure loss in the filter module according to the invention and in a generic filter module with increasing loading.

[0027] Fig. Figure 1 shows a sectional view of a filter module 1 according to the invention for a vehicle air conditioning system. The filter module 1 comprises a flow-through housing 2 and a flow-through particulate filter 3. The particulate filter 3 is arranged in the housing 2 so that it allows flow through it and divides the housing 2 into a raw side 2a and a clean side 2b. The particulate filter 3 is flat and has a raw-side filter surface 3a facing the raw side 2a and a clean-side filter surface 3b facing the clean side 2b. The particulate filter 3 can have a pleated filter material or a pleated filter medium. The particulate filter 3 can also be designed as a curved element.

[0028] The housing 2 further comprises an inlet 4a on the raw side 2a for air to flow into the housing 2 and an outlet 4b on the clean side 2b for air to flow out of the housing 2. The inlet 4a and the outlet 4b are connected to each other so that air can flow through the particle filter 3. The particle filter 3 only partially separates the housing 2, so that a bypass 5 is formed between the raw side 2a and the clean side 2b. Air can flow from the raw side 2a to the clean side 2b around the particle filter 3 via the bypass 5.

[0029] The bypass 5 is formed by a region of the housing 2 that is not filled by the particulate filter 3. In other words, the bypass 5 is formed by the particulate filter 3 leaving a portion of the housing 2 open, or forming a flow-through slot in the housing 2. The particulate filter 3 leaves a flow-through volume in the housing 2 open at an end, perpendicular to a distance direction (not shown) between the inlet 4a and the outlet 4b. The bypass 5 is spaced apart from the inlet 4a and the outlet 4b and is adjacent to the particulate filter 3.

[0030] Within the housing 2, a filter path 6 and a bypass channel 7 are formed. The filter path 6 leads from the inlet 4a to the outlet 4b via the particulate filter 3, and the bypass channel 7 leads from the inlet 4a to the outlet 4b via the bypass 5 around the particulate filter 3. In the embodiment shown here, the inlet 4a and the outlet 4b are opposite each other, and the particulate filter 3 is arranged between the inlet 4a and the outlet 4b. This results in the filter path 6 being at least partially straight.

[0031] By contrast, the bypass channel 7 extends on the raw side 2a from the inlet 4a along the raw-side filter surface 3a to the bypass 5, and on the clean side 2b from the bypass 5 along the clean-side filter surface 3b to the outlet 4b. This gives the bypass channel 7 a siphon-like or U-shaped form. When the filter module 1 is oriented correctly for operation – as shown here – the bypass channel 7 runs downwards from the inlet 4a to the bypass 5 and upwards from the bypass 5 to the outlet 4b. The bypass 5 is then located below the particle filter 3.

[0032] Furthermore, the housing 2 includes a water separator 8. The water separator 8 is formed here by the pipe-side filter surface 3a and a water drainage channel 9. The filter surface 3a forms a water barrier where the water contained in the incoming air can collect on the pipe side and settle downwards. The water drainage channel 9 is formed here on the pipe side 2a of the housing 2 and leads out of the housing 2 to the outside.

[0033] Fig. Figure 2 shows a sectional view of the filter module 1 according to the invention, with the airflow indicated by dashed lines. As the air to be filtered flows through the filter module 1, it enters the raw side 2a of the housing 2 via the inlet 4a. The air then impacts the raw-side filter surface 3a of the particle filter 3 and is divided. The division of the incoming air occurs with varying degrees across the entire filter surface 2a. Part of the air passes through the particle filter 3 in the filter path 6, and part of the air bypasses the particle filter 3 via the bypass 5 in the bypass channel 7. On the clean side 2b, the two portions of the air are combined and flow further towards the outlet 4b.

[0034] The distribution of the air, or rather the size of the respective air portions, depends on the loading of the particle filter 3. As the loading of the particle filter 3 increases, the portion of air flowing through bypass channel 7 or bypass 5 also automatically increases. Accordingly, the flow through the particle filter 3 depends on its loading, ensuring that the filter module 1 provides the maximum volume of air to be conveyed at all times, regardless of the loading of the particle filter 3.

[0035] The portion of air flowing in filter path 6 is filtered by particle filter 3, while the portion of air flowing via bypass channel 7 is routed directly from the raw side 2a to the clean side 2b, or from the inlet to the outlet 4b, and is not filtered. However, when the air is diverted to bypass 5, heavier particles 10 – such as aerosols – are directed by their inertia onto the raw-side filter surface 3a and trapped there. This allows the portion of air flowing in bypass channel 7 to also be partially filtered or cleaned. As a result, the separation efficiency of filter module 1 can be increased. The tests carried out prove that even PM2.5 particles (fine dust with particle size: 100% weighting < 0.5 µm; 0% weighting > 3.5 µm; 50% weighting = 2.5 µm) can be separated by the filter module 1.Therefore, even with a high proportion of the air flowing through bypass 5, sufficient separation of particles can still be achieved.

[0036] Fig. Figure 3 shows a curve of the pressure loss ΔP_1 in the filter module 1 according to the invention with bypass 5 and of the pressure loss ΔP_1' in a generic filter module 1' without bypass with increasing loading B. The two filter modules 1 and 1' have identical particle filters.

[0037] If the particle filter loading of the conventional filter module 1' increases, the pressure drop ΔP_1' also increases. As a result, the amount of air supplied to the air conditioning system decreases when the filter is heavily loaded. In contrast, in the filter module 1 according to the invention, the bypass 5 compensates for the pressure drop ΔP_1, thus preventing an excessive reduction in the air supply to the air conditioning system. Even when the filter module 1 is combined with a filter element in the fresh air / recirculated air section of the air conditioning system, a high fine dust separation efficiency is still achieved.

Claims

[1] Filter module (1) for an air conditioning system of a vehicle for filtering air, - wherein the filter module (1) has a flow-through housing (2) and a flow-through particle filter (3), - wherein the particle filter (3) is arranged in the housing (2) and divides the housing (2) into a raw side (2a) and a clean side (2b), - wherein the housing (2) has a flow-through inlet (4a) on the raw side (2a) and a flow-through outlet (4b) on the clean side (2b), - wherein the inlet (4a) and the outlet (4b) are connected within the housing (2) via the particle filter (3) so that the flow can pass through, characterized by that the filter module (1) has a bypass (5) and the bypass (5) within the housing (2) connects the raw side (2a) and the clean side (2b) of the housing (2) around the particle filter (3) in a way that allows flow through. [2] Filter module (1) according to claim 1, characterized by , - that the bypass (5) is formed by an area of the housing (2) which is not filled with the particle filter (3), and / or - that the bypass (5) is arranged between the inlet (4a) and the outlet (4b), and / or - that the bypass (5) is arranged at a distance from the inlet (4a) and / or the outlet (4b), and / or - that the bypass (7) is formed adjacent to the particle filter (3), and / or - that the bypass (7) and the particle filter (3) lie in a common plane aligned transversely to a connecting line connecting the inlet (4a) and the outlet (4b), and / or - that a flow-through cross-section of the bypass (5) is smaller, preferably several times smaller, than a flow-through cross-section of the particle filter (3). [3] Filter module (1) according to claim 1 or 2, characterized bythat the inlet (4a) and the outlet (4b) are arranged opposite each other in the housing (2) and the particle filter (3) is arranged between the inlet (4a) and the outlet (4b). [4] Filter module (1) according to one of the preceding claims, characterized by , - that the housing (2) has a filter path (6) and the filter path (6) connects the inlet (4a) and the outlet (4b) via the particle filter (3) in a way that allows flow through, and - that the filter path (6) is at least partially straight. [5] Filter module (1) according to one of the preceding claims, characterized by , - that the particle filter (3) has a raw-side filter surface (3a) facing the raw side (2a) and the raw-side filter surface (3a) is arranged opposite the inlet (4a), and / or - that the particle filter (3) has a raw-side filter surface (3a) facing the raw side (2a) and the raw-side filter surface (3a) is aligned perpendicular to a longitudinal center axis of the inlet (4a). [6] Filter module (1) according to one of the preceding claims, characterized by , - that the particle filter (3) has a clean-side filter surface (3b) facing the clean side (2b) and the clean-side filter surface (3a) is arranged opposite the outlet (4b), and / or - that the particle filter (3) has a clean-side filter surface (3b) facing the clean side (2b) and the clean-side filter surface (3b) is aligned perpendicular to a longitudinal center axis of the outlet (4b). [7] Filter module (1) according to one of the preceding claims, characterized by , - that the housing (2) has a bypass channel (7) through which flow can pass and the bypass channel (7) connects the inlet (4a) and the outlet (4b) via the bypass (5) in a flow-through manner, and - that the bypass channel (7) is siphon-like. [8] Filter module (1) according to claim 7, characterized by , - that a raw-side section of the bypass channel (7) assigned to the raw side (2a) is aligned parallel to a raw-side filter surface (3a) of the particle filter (3) facing the raw side (2a), and / or - that a clean-side section of the bypass channel (7) assigned to the clean side (2b) is aligned parallel to a clean-side filter surface (3b) of the particle filter (3) facing the clean side (2b). [9] Filter module (1) according to claim 7 or 8, characterized by , - that a raw-side section of the bypass channel (7) assigned to the raw side (2a) leads in an operationally aligned filter module (1) from the inlet (4a) downwards to the bypass (5), and / or - that a clean-side section of the bypass channel (7) assigned to the clean side (2b) leads in an operationally aligned filter module (1) from the bypass (5) upwards to the outlet (4b), and / or - that the bypass (5) is arranged in an operationally aligned filter module (1) below the particle filter (3). [10] Filter module (1) according to one of the preceding claims, characterized by , - that the filter module (1) has a water separator (8) with a water barrier and a water drainage channel (9), - that the water barrier is formed by a raw-side filter surface (3a) of the particle filter (3) facing the raw side (2a) of the housing (2), and - that the water drainage channel (9) is formed on the raw side (2a) of the housing (2) and leads out of the housing (2) to the outside. [11] Air conditioning system of a vehicle, - the air conditioning system has a fresh air inlet and a fresh air / recirculated air mixing point, - the air conditioning system has a filter module and the filter module is connected downstream of the fresh air inlet, characterized by , - that the filter module (1) is designed according to one of the preceding claims, and - that the air conditioning system has a filter element and that the filter element is located downstream of the fresh air / recirculated air mixing point.

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