Water drain for the filter of a vehicle air conditioning device, having a check valve function

Abstract

The invention relates to an air conditioning device for a vehicle, the air conditioning device comprising an air duct (1) for guiding air, a fan for generating an air flow in the air duct, and an air filter (3), wherein a first flap (5) separates a water collection region (9) from a water outlet (7), and wherein the first flap is rotatably mounted and, due to gravity and / or a pressure gradient between the water outlet and the region (11) of the air duct (1) located downstream of the air filter (3) with respect to the air flow direction, is biased towards assuming a water-tight and air-tight closed position, and opens only when the water pressure from a water level in the water collection region (9) exceeds a threshold value, resulting in water flowing from the water collection region (9) through the open first flap (5) into the water outlet (7).

Description

[0001] Water drain for filter of a

[0002] Vehicle air conditioning device with backflow function

[0003] The invention relates to an air conditioning device for a vehicle, as well as a vehicle with such an air conditioning device.

[0004] Filters for vehicle air conditioning systems must typically be kept free of standing moisture to extend the service life of the filters and enable them to function as desired. Moisture can occur in an air duct with such a filter when moist or wet air is drawn in, for example in the case of fog, snowfall, rain, water stirred up from the environment, or similar. However, liquid water can also occur in the air duct due to condensation, particularly in air conditioning systems with a cooling function, when gaseous water or water droplets condense in the air and collect at the bottom of the air duct. There is then a risk that such a filter will be exposed to the influence of liquid water for a longer period of time. In the prior art, water paths for draining away separated water are typically provided to solve this problem.

[0005] DE 102015200 851 A1 relates to an assembly for an air conditioning system for air-conditioning the interior of a vehicle, comprising an air filter for filtering the intaken fresh air, which is arranged in a fresh air path in such a way that it separates a raw side from a clean side of the fresh air path, and a water path for removing water separated from the fresh air on the raw side of the air filter. A water filter for filtering the separated water is arranged in the water path, separating a raw side from a clean side of the water path. Thin, space-saving filters are increasingly being used to filter blown air for motor vehicles. Under heavy loads, such as a collapsing filter, an oversaturated filter, particularly when exposed to fog, snow, or water, or other influences as described above, these filters sometimes allow small amounts of water to pass through.This means there is a risk of water collecting behind the filter in the direction of flow. The water may then collect in the filter's downstream area but must be drained away because the filter cannot be left wet for extended periods to ensure it functions properly. If an open water outlet is introduced into the area behind the filter, this can undesirably create an air bypass. The suction effect of a fan creates an air flow through the filter, but the filter opposes this air flow with flow resistance. In addition, the flow velocity in this area tends to create a negative pressure compared to the stagnant air in the surrounding area. This is precisely what we want to avoid, however, as it would mean introducing unfiltered air into the area behind the filter and thus rendering the filter's function at least partially ineffective.

[0006] The object of the invention is to provide an air conditioning device which has a drainage function for an area behind its filter for filtering an air flow, but which, if possible, does not form an undesirable bypass around the filter.

[0007] The invention is based on the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims.

[0008] A first aspect of the invention relates to an air conditioning device for a vehicle, comprising an air duct for conducting air, a fan for generating an air flow in the air duct, an air filter, and a drainage device having a first flap and a water outlet, wherein the first flap separates a water collection area from the water outlet, wherein the water collection area is a region of the air duct located behind the air filter with respect to the air flow direction and / or is connected to such a region in a water-conducting manner, and the water collection area lies with its lowest point below a lowest point of the air filter in order to keep water collecting in the water collection area away from the air filter,and wherein the first flap is rotatably mounted and, by gravity and / or by a pressure gradient between the water outlet and the area of ​​the air duct located behind the air filter with respect to the air flow direction, strives to enter a watertight and airtight closed position and only opens when the water pressure of a water level in the water collection area exceeds a threshold value, so that water from the water collection area flows through the opened first flap into the water outlet.

[0009] The water level required to open the first flap in the water collection area can be adjusted accordingly by the design. In any case, the water collection area requires more than just a few drops of water to open the first flap. This is simply due to the fact that the first flap is pressed against a stop with a certain force, either by gravity alone, by a pressure gradient between a higher pressure in the water outlet compared to the area of ​​the air duct behind the air filter in terms of the direction of air flow, or by gravity and the pressure gradient combined. A further mechanism can also be provided, for example a controlled actuator and / or a mechanical spring, such as a torsion spring.

[0010] If the first flap is forced into its closed position by spring force and / or gravity, this mechanism is essentially independent of whether the fan is active and generating airflow through the filter. However, if the fan is active, a pressure jump tends to occur from an area in front of the filter to an area behind the filter, as the filter exerts a flow resistance on the airflow. The flow behind the filter therefore tends to have a lower pressure. This pressure tends to be reduced even further in the area behind the filter if a higher flow velocity is established, since, according to Bernoulli, pressure decreases with increasing fluid velocity.

[0011] The operation of the fan therefore advantageously creates a self-locking effect that forces the first flap into its closed position and thus ensures that all the air drawn in passes through the filter, especially when the fan is operating.

[0012] By essentially forcing the first flap into its closed position on its own, it closes a bypass that could otherwise occur for air that could flow through the water outlet through the open first flap into the area of ​​the air duct located behind the air filter in terms of the direction of air flow and thus bypass the air filter, allowing unfiltered air to reach this area.

[0013] The first flap is therefore only opened by a corresponding water level in the water collection area when the water pressure of this collecting water overcomes the force pushing the first flap into its closed position. In this case, the collecting water flows through the opening flap into the water outlet, without (significant) air from the outlet being able to flow back into this area behind the filter. This is because even air potentially flowing from the water outlet into this area and thus directly through the filter would in turn exert a force on the first flap, pushing the first flap into its closed position. The first flap thus acts as a check valve, preventing air outside the filter from reaching an area behind the filter.

[0014] However, the area behind the filter can be drained, ensuring that the filter does not remain wet with the water collecting in the water collection area. The force pushing the first flap into its closed position is preferably designed in relation to the water pressure, depending on the water level, so that the water level never reaches the filter itself. Instead, the collecting water is drained through the water outlet by an opening first flap. This ensures a dry filter throughout the operating life of the air conditioning system.

[0015] Preferably, the drainage device is arranged below a filter. Furthermore, the drainage device and the filter are preferably arranged in a negative pressure region of the air conditioning device, i.e., upstream of the fan in the flow direction. The water outlet can lead into a collection container, into an area surrounding the vehicle, or back into an area upstream of the filter with respect to the flow through the filter.

[0016] In another embodiment, it is provided that the drainage device and the filter are arranged in an overpressure area of ​​the air conditioning device, that is to say behind the fan in the flow direction.

[0017] According to an advantageous embodiment, the water collection area has a barrier that forms a stop for the first flap. The barrier also preferably forms a step that the water collecting above the lowest point of the water collection area must overcome.

[0018] According to a further advantageous embodiment, the first flap can be pivoted at most into an oblique position relative to a perpendicular to the floor of the water collection area when it abuts against the floor.

[0019] According to a further advantageous embodiment, the water outlet leads into a region of the air duct located upstream of the air filter with respect to the air flow direction. This corresponds to a water return from the area behind the air filter to the area upstream of the air filter in the air duct. This option is particularly useful if there is a connection to a water outlet from the air duct in the area upstream of the air filter.

[0020] According to a further advantageous embodiment, the water outlet leads out of the air duct.

[0021] According to a further advantageous embodiment, the drainage device has a second flap which is rotatably mounted at a first end and has a float at a second end opposite the first end, wherein the second flap separates a region of the air duct located upstream of the air filter with respect to the air flow direction from the water outlet, and wherein the second flap strives into a watertight and airtight closed position by gravity and / or by a pressure gradient between the water outlet and the region of the air duct located upstream of the air filter and only opens due to the hydrostatic buoyancy of the float in the water.

[0022] According to a further advantageous embodiment, the water outlet has labyrinth-shaped water guide channels.

[0023] According to a further advantageous embodiment, during operation of the blower, a pressure in the region of the air duct in front of the air filter is greater than a pressure in the water outlet and the pressure in the water outlet is greater than a pressure in the region of the air duct behind the air filter.

[0024] The pressure drop between the water outlet and the area of ​​the air duct behind the air filter causes the first flap to tend to close automatically. Only hydrostatic pressure from this relatively low-pressure area in the area of ​​the air duct behind the air filter can cause the first flap to open, draining the water that caused this through the water outlet. If a second flap is provided as described, the pressure drop between an area in the air duct in front of the air filter and the water outlet is also responsible for the second flap tending to close. The second flap is only pivoted into an open position by the hydrostatic buoyancy of its float.In such a configuration, the first flap and the second flap preferably have the same direction of rotation in order to move from their closed position to an open position.

[0025] A further aspect of the invention relates to a vehicle with an air conditioning device as described above and below.

[0026] Advantages and preferred developments of the proposed vehicle result from an analogous and analogous transfer of the statements made above in connection with the proposed air conditioning device.

[0027] Further advantages, features, and details will become apparent from the following description, which – where appropriate with reference to the drawings – describes at least one embodiment in detail. Identical, similar, and / or functionally equivalent parts are provided with the same reference numerals.

[0028] They show:

[0029] Fig. 1 to 4 show air conditioning devices according to embodiments of the invention. The representations in the figures are schematic and not to scale.

[0030] Fig. 1 shows a first embodiment of an air conditioning device for a vehicle. An air duct 1 serves to guide sucked-in air. The intake takes place with the aid of a fan, so that an air flow is generated in the air duct 1. The air flow is indicated in Figs. 1 to 4 by two voluminous arrows drawn one behind the other with dashed lines. In these figures, the air flow flows through an air filter 3 to remove dirt and particles from the air flow. The air filter 3 has a resistance that is dependent on the speed of the air flow, which leads to a pressure jump in the air flow. Under certain circumstances, it can occur that liquid or gaseous water flows through the air filter 3 and precipitates as liquid water in a region 11 of the air duct 1 behind the air filter 3 with respect to the flow direction of the air flow.A bottom side of the air duct 1 is therefore beveled so that this liquid flows into a water collection area 9 below the air filter 3. The water collection area 9 is deliberately located lower than a lower side of the air filter 3, so that even if the water level in the water collection area 9 rises, the air filter 3 remains unaffected and is not affected by the wetness of this water.

[0031] Viewed in the direction of gravity, a first flap 5 is provided below the air filter 3. This separates a water outlet 7 from the water collection area 9 and the area 11 of the air duct 1 behind the air filter 3. When the fan is in operation, the pressure difference described above arises, so that an ambient pressure in the water outlet 7 is greater than an ambient pressure in the area 11 of the air duct 1 - viewed in the direction of air flow - behind the air filter 3. This forces the first flap 5 into a closed position, thus preventing air from being forced by the fan via the water outlet 7 into the area 11 of the air duct 1 behind the air filter 3, which would accordingly enter the area 11 unfiltered.In order to nevertheless be able to drain away the water collecting in the water collection area 9, the area and height of the first flap 5 are designed such that when the water level in the water collection area 9 is above a certain threshold value, but before the water level of the air filter 3 is reached, the first flap 5 opens and the water thereby flows out of the water collection area 9 until the pressure gradient and the effect of gravity on the first flap 5 in turn exceeds the static pressure of the water in the water collection area 9 and the resulting force on the first flap 5 and the first flap 5 thus closes again.

[0032] Fig. 2 shows an alternative air conditioning device. A separate stop is provided at the bottom of the water collection area to stop the first flap 5 from pivoting. This stop is necessary because the first flap 5 is located above a flat bottom of the water collection area 9 and does not abut a side wall of the water outlet 7. In this case, the water outlet 7 can also be arranged in an area 13 in front of the air filter 3 in the air duct 1.

[0033] Fig. 3 shows another air conditioning device. In contrast to the one in Fig. 2, this one features a flat bottom of the water collection area 9 instead of a stop for the first flap 5. However, the first flap 5 is longer than the height between a pivot joint below an air filter 3 and a bottom of the water collection area 9. The first flap 5 can therefore only be moved to a maximum angle when it is moving toward a closed position. In this case, the influence of gravity acting on the first flap 5 is additionally utilized to allow it to move independently toward its closed position.

[0034] Fig. 4 shows a further air conditioning device. Here, the water outlet 7 serves not only to drain the water collection area 9 for water from the area 11 of the air duct 1 behind the air filter 3, but also to drain water from an area 13 of the air duct 1 upstream of the air filter 3. For this purpose, a second flap 15 is provided, which is rotatably mounted similarly to the first flap 5, namely below the air filter 3, but has a float 17 at its end opposite the rotatable mounting. If the float 17 is sufficiently immersed in water that accumulates in the area 13 upstream of the air filter 3, the float 17 is lifted by hydrostatic buoyancy, which in turn causes the second flap 15 to pivot into an open position. The water can then flow in front of the second flap 15 below the float 17 and drain into the water outlet 7.Without the influence of the water on the float 17, the second flap 15 would tend to be forced into its closed position because, due to the influence of gravity, it is forced against a stop in front of the water outlet 7 and, moreover, during operation of the blower, it is forced into this closed position by the higher pressure in the area 13 in front of the air filter 3 compared to an ambient pressure in the water outlet 7.

[0035] Although the invention has been illustrated and explained in detail by preferred embodiments, the invention is not limited by the disclosed examples, and other variations may be derived therefrom by those skilled in the art without departing from the scope of the invention. It is therefore clear that a multitude of variations exist. It is also clear that exemplary embodiments are truly only examples and should not be construed as limiting the scope, possible applications, or configuration of the invention in any way.Rather, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete terms, whereby the person skilled in the art, with knowledge of the disclosed inventive concept, can make various changes, for example with regard to the function or the arrangement of individual elements mentioned in an exemplary embodiment, without departing from the scope of protection defined by the claims and their legal equivalents, such as further explanations in the description.

Claims

Mercedes-Benz Group AG Frank Thoms February 5, 2025 Patent claims 1. An air conditioning device for a vehicle, comprising an air duct (1) for conducting air, a fan for generating an air flow in the air duct (1), an air filter (3), and a drainage device having a first flap (5) and a water outlet (7), wherein the first flap (5) separates a water collection area (9) from the water outlet (7), wherein the water collection area (9) is a region (11) of the air duct (1) located behind the air filter (3) with respect to the air flow direction and / or is connected to such a region (11) in a water-conducting manner, and the water collection area (9) is located with its lowest point below a lowest point of the air filter (3) in order to keep water collecting in the water collection area (9) away from the air filter (3),and wherein the first flap (5) is rotatably mounted and, by gravity and / or by a pressure gradient between the water outlet (7) and the area (11) of the air duct (1) located behind the air filter (3) with respect to the air flow direction, strives for a watertight and airtight closed position and only opens due to water pressure of a water level in the water collection area (9) above a threshold value, so that water from the water collection area (9) flows through the opened first flap (5) into the water outlet (7).

2. Air conditioning device according to claim 1, wherein the water collection area (9) has a barrier which forms a stop for the first flap (5).

3. Air conditioning device according to claim 1, wherein the first flap (5) can be moved at most into an inclined position to a perpendicular to the bottom of the water collecting area (9) when abutting against the Floor is pivotable.

4. Air conditioning device according to one of claims 1 to 3, wherein the water outlet (7) leads into a region (13) of the air duct (1) located behind the air filter (3) and in front of the air filter (3) with respect to the air flow direction.

5. Air conditioning device according to one of claims 1 to 3, wherein the water outlet (7) leads out of the air duct (1).

6. Air conditioning device according to one of the preceding claims, wherein the drainage device has a second flap (15) which is rotatably mounted at a first end and has a float (17) at a second end opposite the first end, wherein the second flap (15) separates a region (13) of the air duct (1) located upstream of the air filter (3) with respect to the air flow direction from the water outlet (7), and wherein the second flap (15) strives into a watertight and airtight closed position by gravity and / or by a pressure gradient between the water outlet (7) and the region (13) of the air duct (1) located upstream of the air filter (3) and only opens due to hydrostatic buoyancy of the float (17) in the water.

7. Air conditioning device according to one of the preceding claims, wherein the water outlet (7) has labyrinth-shaped water guide channels.

8. Air conditioning device according to one of the preceding claims, wherein during operation of the fan a pressure in the region (13) of the air duct (1) in front of the air filter (3) is greater than a pressure in the water outlet (7) and the pressure in the water outlet (7) is greater than a pressure in the region (11) of the air duct (1) behind the air filter (3).

9. Vehicle with an air conditioning device according to one of the preceding claims.

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