NOX REDUCTION IN THE VEHICLE INTERIOR

Description

[0001] The invention relates to a filter unit for removing nitrogen oxides from air, an arrangement for reducing the nitrogen oxide content of the air in an enclosed space, a motor vehicle comprising the arrangement, and a method for removing nitrogen oxides from the air in an enclosed space.

[0002] Currently, there are very limited options for reducing exhaust emissions inside a vehicle, for example, from vehicles ahead. One option is the "recirculation" setting on the air conditioning system. This prevents a large amount of outside air from being drawn in. Another option is the use of HEPA / activated carbon filters, which are already installed in some vehicles. However, both of these technical solutions are only of limited use in reducing NOx emissions.

[0003] The disadvantage of the "recirculation setting" is that pollutants such as CO2 and NOx accumulate very quickly in the indoor air, making this a very short-term solution. Furthermore, humidity also rises rapidly. While HEPA filters in combination with activated carbon filters do have a filtering effect, many filters have a very limited capacity and must be replaced when full; the filter material cannot be recycled.

[0004] DE 198 38 996 A1 relates to an air conditioning system with an activated carbon filter for cleaning the air supplied to the interior of a motor vehicle. A device for cleaning by heating the filter and the air contained within it is provided, and the air contaminated with waste products can be expelled from the filter by means of a cleaning airflow. The activated carbon is in contact with a temperature-controlled or temperature-regulated heater, which heats the activated carbon and the air contained in the filter while the cleaning airflow passes through the filter.

[0005] From DE 38 19 002 A1, a filter for removing odors and pollutants that enter vehicle cabins via the ventilation system is known. The filter material is designed as a cassette that is inserted into the airflow of the ventilation system and can be easily replaced. It consists of a PU foam carrier material to which adsorbent particles made of polymeric material are fixed by means of an adhesive compound on the outer and inner surfaces.

[0006] From DE 10 2017 201 367 A1 a device for cleaning CO2-laden air in a closed room is disclosed, comprising an adsorption device for adsorbing CO2 from the air supplied to the adsorption device, a desorption device associated with the adsorption device for desorbing adsorbed CO2, and a discharge device for removing the desorbed CO2.

[0007] DE 10 2018 000 378 A1 relates to a system and a process for the utilization of nitrogen oxides formed in combustion engines, with which the nitrogen oxides can be used for the production of liquid or solid chemicals.

[0008] US patent 2015 / 375602 A1 discloses an air filter assembly for filtering air in a vehicle, comprising a housing that can be positioned inside the vehicle. A first filter and a second filter, comprising a variety of filter media, are coupled to the housing. A fan forces air through the first and second filters, thus filtering particles contained in the air inside the vehicle.

[0009] JP 2012 200592 A relates to a device for removing toxic substances, comprising a preprocessing unit arranged in a path through which the air of the treatment object, containing the toxic gas component, is passed, and a postprocessing unit arranged on the downstream side of the preprocessing unit. The preprocessing unit contains a porous adsorbent for adsorbing the toxic gas components in the air of the treatment object, a photocatalyst, and an ultraviolet lamp for irradiating the photocatalyst with ultraviolet rays.The post-processing unit has a vapor-liquid contact unit to bring the air of the object being treated, which has been treated by the pre-processing unit, into contact with water, and an electrolytic treatment unit equipped with an electrode to electrochemically treat the water that has come into contact with the air of the object being treated in the vapor-liquid contact section.

[0010] DE 28 20 313 A1 discloses a filter pad for the air intake ducts to the passenger compartment of motor vehicles, consisting of a square, flat cushion reinforced at the edges by an adhesive strip. This also serves to fix the pad to the intake duct. The cushion is filled with a layer several centimeters thick of a chemical absorber, e.g., expanded perlite, which is soaked in sodium hydroxide solution and coated with lime and copper dust or mixed with activated carbon.

[0011] DE 30 28 433 A1 discloses a device for separating acidic gases such as SO₂, NOx, hydrocarbons, and solids from the air. In this device, the contaminated air is either forced or drawn through two chemisorption masses, a catalyst, and heating and cooling elements.

[0012] Against this background, the invention aims to provide devices and methods with which nitrogen oxides can be removed from indoor air and the removed nitrogen oxides can later be used for further material purposes.

[0013] The problem is solved according to the invention by devices having the features of claim 1, claim 6 or claim 7, and a method having the features of claim 10. Embodiments and further developments of the invention are shown in the dependent claims, the description and the illustrations.

[0014] The invention relates to a filter unit for removing nitrogen oxides from the air in an enclosed space (indoor air). The filter unit comprises a closed housing which has a pipe at one end for introducing air into the filter unit and a pipe at the opposite end for exhausting air from the filter unit, with fans arranged in each pipe. The pipes are each connected to a pressure chamber in the housing. At least two granule chambers are arranged between the pressure chambers, containing an adsorbent granulate capable of adsorbing nitrogen oxides. The at least two granule chambers are each separated from one another by an intermediate layer or filter layer.

[0015] In one embodiment, the enclosed space is a vehicle interior, in particular a passenger compartment. In another embodiment, the enclosed space is a room within a building, for example a living space or a garage.

[0016] In one embodiment, the housing has the form of a closed cylinder. The pipes for introducing air into the filter unit and for expelling air from the filter unit can be arranged radially or axially on the housing. The fans can operate in either suction or pressure mode, as desired.

[0017] The filter unit comprises at least two granule chambers. In one embodiment, the filter unit comprises three granule chambers. The number of granule chambers in the filter unit and the distribution of the internal volume of the filter unit can vary depending on the application. The presence of multiple granule chambers within the filter unit allows for the use of different adsorbent granules in a single filter unit. These adsorbent granules can differ in their particle size and / or chemical composition.

[0018] In one embodiment, the adsorbent granules comprise at least one zeolite. Zeolites capable of adsorbing nitrogen oxides are known in principle to those skilled in the art. Examples include ZSM-5, Zeolite Y, and Mordenite.

[0019] In another embodiment, the adsorbent granules comprise alkali oxides or alkaline earth oxides or alkali carbonates or alkaline earth carbonates, optionally on a granular support material. In a particular embodiment, the adsorbent granules comprise barium oxide, optionally in combination with platinum and rhodium.

[0020] The filter unit according to the invention is filled with adsorbent granules that can be easily replaced and recycled. The filter unit can be used both for filtering fresh air supplied to the interior and for filtering the interior air itself, and is placed accordingly in the air supply or in the interior. The use of the filter unit can achieve a permanent reduction in the NOₓ concentration in the interior.

[0021] In one embodiment, the filter unit and / or the adsorbent granules are designed to be replaced and reprocessed after use. The adsorbent granules can be easily removed and replaced, for example, when the filter unit is saturated with NOₓ. The granules can be recycled by separating the NOₓ molecules from the granules, for example, by applying heat. The resulting NOₓ gas stream is collected and fed into conversion processes.

[0022] In one embodiment, the filter unit is portable, allowing it to be used variably in different indoor environments. For example, it could be used either inside a vehicle or in a building.

[0023] The invention also relates to an arrangement for reducing the nitrogen oxide (NOx) content of the air in an enclosed space, comprising a supply system for ambient air into the enclosed space and / or a recirculation system for circulating air located in the enclosed space, wherein the supply system and / or the recirculation system includes a nitrogen oxide filter for reducing the nitrogen oxide content of the supplied ambient air. According to the invention, at least one nitrogen oxide filter comprises a filter unit according to the invention with an adsorbent granulate for NOx.

[0024] In one embodiment, the arrangement comprises both a supply system for ambient air into the enclosed space and a recirculation system for circulating air located in the enclosed space. In another embodiment, both the supply system and the recirculation system comprise a filter unit according to the invention.

[0025] In one embodiment, the enclosed space is a vehicle interior, in particular a passenger compartment. In another embodiment, the enclosed space is a room within a building, for example a living space or a garage.

[0026] The invention also relates to a motor vehicle with an interior and an air conditioning system for the interior, wherein the air conditioning system comprises an arrangement according to the invention.

[0027] In one embodiment, the motor vehicle comprises an arrangement according to the invention with two filter units, namely a first filter unit (fresh air filter) which is arranged in a leaf trap or in a water box of the motor vehicle and filters air drawn into the motor vehicle before entering the air conditioning system, and a second filter unit (cabin filter) which is arranged in a passenger compartment of the motor vehicle and filters the cabin air.

[0028] In one embodiment, the motor vehicle includes control electronics which are also designed to control the arrangement according to the invention. In another embodiment, the filter units can be controlled separately by means of a software application ("app"). In one embodiment, the app is installed on a user's mobile device, for example, a laptop, tablet, or smartphone. In another embodiment, the app is part of a user interface of the motor vehicle's on-board electronics.

[0029] The invention also relates to a method for removing nitrogen oxides from the air in an enclosed space, in which ambient air is passed through at least one filter unit according to the invention and then supplied to the enclosed space. In one embodiment of the method, the ambient air is outside air to be supplied to the enclosed space. In another embodiment of the method, the ambient air is the air already present in the enclosed space. In yet another embodiment of the method, both the outside air to be supplied to the enclosed space and the air already present in the enclosed space are each passed through a filter unit according to the invention.

[0030] In one embodiment, the enclosed space is a vehicle interior, in particular a passenger compartment. In another embodiment, the enclosed space is a room within a building, for example a living space or a garage.

[0031] The arrangement according to the invention continuously generates good, fresh air for the vehicle's occupants. The adsorbent granules used in the cartridges can be easily removed and replaced once saturated with NOₓ. The granules can be recycled, and the desorbed NOₓ can be used for material purposes. Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.

[0032] 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.

[0033] The invention is schematically illustrated in the figures with reference to one embodiment and is further described with reference to the figures. It shows: Figure 1 is a schematic representation of a motor vehicle with an embodiment of the interior air purification system according to the invention; Figure 2 is a diagram of measured nitrogen oxide concentrations during a test drive of the motor vehicle. Figure 1 Figure 3 shows a schematic representation of an embodiment of a filter unit according to the invention.

[0034] Figure 1 Figure 10 shows a motor vehicle with an embodiment of the arrangement according to the invention for interior air purification. Two filter cartridges 11, 12 are used: a fresh air filter 11, which is arranged, for example, in the leaf guard or in the water box of the motor vehicle, and an interior filter 12, which is arranged in the passenger compartment, for example, in the area of ​​the rear seats.

[0035] In the fresh air filter 11, the intake air is continuously filtered before entering the air conditioning system by one or more adsorbing filter granules (500–2000 ml), which specifically retain NOₓ molecules. A single pass through the granules removes approximately 95% of the nitrogen oxides from the air.

[0036] The cabin air filter 12 continuously filters the interior air through one or more adsorbent filter granules (1000–2000 ml). The cabin air is filtered multiple times through the granules, resulting in an overall NOx absorption rate of approximately 90%. The cabin air filter can be permanently installed or removable, allowing it to be carried when leaving the vehicle and used at home.

[0037] Figure 2 shows the results from during a test drive with the in Fig. 1The nitrogen oxide measurements performed on the vehicle shown are clearly evident. It is readily apparent that the NO₂ limit values ​​are predominantly exceeded in the ambient air (raw air) supplied to the vehicle during the test drive. The exposure of the vehicle occupants would be consistently very high. The use of the fresh air filter 11 located in the leaf guard and the cabin air filter 12 located in the interior significantly reduces the NO₂ concentration. The use of the cabin air filter 12 also noticeably reduces the NO₂ concentration. Consequently, considerably less new NO₂ can form in the vehicle interior.

[0038] Figure 3Figure 1 schematically shows the structure of one embodiment of the filter unit 1 according to the invention. The cylindrical housing of the filter unit 1 has an air inlet 4 at one longitudinal end for air containing pollutants, which can be arranged radially or axially. A fan 3 is arranged in the air inlet 4 and can be used variably in suction or pressure operation. At the other longitudinal end of the housing, an air outlet 2 for purified air is provided, which can also be arranged radially or axially. A fan 3 is also arranged in the air outlet 2 and can be used variably in suction or pressure operation.

[0039] Internally, the filter unit 1 has a pressure chamber 5 at each end, which serves to homogenize the air entering and leaving the filter unit 1 and ensures a uniform gas flow across the entire cross-section of the filter unit 1. The illustrated filter unit 1 has three granule chambers 6, which are separated from each other and from the pressure chambers 5 by filter inserts 7. In one embodiment, the filter inserts 7 are stainless steel or wire mesh screens; in another embodiment, they are plastic mesh screens. The filter inserts 7 have a mesh size that is smaller than the diameter of the granule particles in the granule chambers 6. The filter inserts 7 prevent the granules from the different granule chambers 6 from mixing. The number of granule chambers 6 and their arrangement within the filter unit 1 can be varied depending on the application. Reference symbol list

[0040] 1 Filter unit with housing 2 Filter air outlet 3 Fan 4 Pollutant air inlet 5 Pressure chamber 6 Granule chamber 7 Intermediate / filter insert 10 Motor vehicle 11 Cartridge 12 Cabin air filter

Claims

1. Filter unit (1) having a closed housing which has at one end a pipe (4) for introducing air into the filter unit (1) and at an opposing end a pipe (2) for discharging air from the filter unit, wherein fans (3) are arranged in each case in the pipes (2, 4), and wherein the pipes (2, 4) are in each case connected to a pressure chamber (5) in the housing, and characterized in that between the pressure chambers (5) at least two granulate chambers (6) which contain an adsorber granulate which is capable of adsorption of nitrogen oxides are arranged, and wherein the at least two granulate chambers (6) are in each case separated from each other by means of an intermediate inlay / filter inlay (7).

2. Filter unit (1) according to claim 1, wherein the housing is in the form of a closed cylinder and the pipes (2, 4) are arranged radially on the housing.

3. Filter unit (1) according to claim 1, wherein the housing is in the form of a closed cylinder and the pipes (2, 4) are arranged axially on the housing.

4. Filter unit (1) according to any one of claims 1 to 3, wherein the adsorber granulate comprises at least one zeolite.

5. Filter unit (1) according to any one of claims 1 to 4, wherein the filter unit (1) and / or the adsorber granulate are provided to be replaced and prepared again after use.

6. Arrangement for reducing the nitrogen oxide content of the air in a closed space, comprising a supply installation for ambient air in the closed space and / or an ambient air installation for circulating air located in the closed space, wherein the supply installation and / or the ambient air installation comprise a nitrogen oxide filter for reducing the nitrogen oxide content of supplied ambient air, wherein at least one nitrogen oxide filter comprises a filter unit (1) according to any one of the preceding claims.

7. Motor vehicle (10) having an interior and an air-conditioning unit for the interior which comprises an arrangement according to claim 6.

8. Motor vehicle (10) according to claim 7, wherein the arrangement comprises a first filter unit (11) which is arranged in a leaf trap or in a water tank of the motor vehicle (10) and filters air drawn into the motor vehicle before entering the air-conditioning system, and a second filter unit (12) which is arranged in a passenger compartment of the motor vehicle (10) and filters the interior air.

9. Motor vehicle according to claim 7 or 8, which comprises an electronic control system which is configured to control the arrangement.

10. Method for removing nitrogen oxides from the air in a closed space, in which ambient air is directed through at least one filter unit (1) according to any one of claims 1 to 5, and is then supplied to the closed space.