Title

Filter arrangement air management system, method for determining a contamination of a filter material, and method for controlling an air quality

Technical field

[0001] Various aspects of this disclosure relate to a filter arrangement, an air management system, a method for determining a contamination of a filter material, and a method for controlling an air quality within an interior space.

Background

[0002] Filters of ventilation systems have to be cleaned or replaced regularly. For example, a filter is given a lifetime of e.g. 6 months to 1 year in operation, based on experience on how dirty it is expected to become during this time and based on hygienic aspects. Often the actual usage of the filter and/or how dirty the filter actually is are not taken into account when deciding when to clean or replace it. However, a replacement at a certain level of filter contamination may be desired, as too early replacement causes higher costs for labor and spare parts, while too late replacement increases the energy consumption of the ventilation system (e.g. of a fan) due to higher pressure drop. Hence, it may be desired to determine the contamination of the filter reliably. The contamination of the filter may decrease the filter performance, which may lead to a contamination of the air supplied to an interior space by the ventilation system. This may, for example, severely affect people with respiratory diseases and/or allergies and may lead to allergic reactions. Therefore, it may also be desirable to provide an air management system capable to improve the air quality (e.g., containing fewer particles, such as dust and/or pollen) in an indoor environment.

Summary

[0003] Various embodiments relate to a filter arrangement including: a filter material for filtering an air flow, wherein the filter material includes a plurality of filter pleats; an optical sensor arranged at least partially within a filter pleat of the plurality of filter pleats and configured to radiate light onto the filter material within the filter pleat, to detect light reflected from the filter material, and to generate a sensor signal depending on the detected light; and an evaluation unit configured to receive the sensor signal from the optical sensor and to generate an output signal depending on the received sensor signal, wherein the output signal indicates a contamination of the filter material. This allows to clean or replace the filter at an appropriate contamination level (in some aspects referred to as clogging level), thereby reducing the costs for labor and spare parts as well as the energy consumption, as described above.

[0004] The filter arrangement may be employed within an air management system. In addition to the filter arrangement, the air management system may include: an interior space; a first supply line for supplying the air flow to the filter material; a second supply line fluidly connected to the first supply line for supplying the air flow filtered by the filter material into the interior space; a particle sensor configured to detect a concentration of particles contained in the air flow which is supplied to the filter material via the first supply line, the particles having a size in a predetermined size range; a gas sensor configured to detect an air quality of the air flow which is supplied to the filter material via the first supply line; and a control device configured to provide instructions for controlling the air quality within the interior space in dependence on the output signal of the evaluation unit, the detected concentration of particles, and the detected air quality. This improves the air quality within the interior space, thereby improving a sensation of people (e.g., of people with respiratory diseases and/or allergies) located in the interior space.

Brief description of the drawings

[0005] The invention will be better understood with reference to the detailed description when considered in conjunction with the non-limiting examples and the accompanying drawings, in which:

- FIG. 1 and FIG. 3 each show an air management system according to various embodiments;

- FIGS. 2 A to 2C and FIG. 4 A each show aspects of a filter arrangement according to various aspects;

- FIGS. 4B to 4D show a sensor arrangement according to various embodiments.

- FIG. 5 A shows diagrams schematically illustrating the loading of a filter material with contaminants; - FIG. 5B and FIG. 5C show diagrams illustrating the relation between a contamination of a filter material and an intensity of light reflected from the filter material; and

- FIG. 6 and FIG. 7 each show a method according to various embodiments.

Detailed description

[0006] The following detailed description refers to the accompanying drawings that show, by way of illustration, specific details and embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure. Other embodiments may be utilized and structural, and logical changes may be made without departing from the scope of the disclosure. The various embodiments are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments. Embodiments described in the context of the filter arrangement and/or the air management system may be analogously valid for the methods described herein, and vice versa.

[0007] FIG. 1 shows an air management system 100. The air management system 100 may include an apparatus 110 having an air duct 102. The air duct 102 may be provided with a filter 101. The filter 101 may be or may include a woven filter. The filter 101 may be, for example, a high-efficiency particulate (HEP A) filter. The apparatus 110 may be a ventilation system that draws in outside air (represented by air flow 214 shown, for example, in FIG. 3) through the air duct 102. For example, the outside air is to be cleaned of contaminants, such as pollen and dust. The apparatus 110 may also be a building and the air duct 102 may serve to supply air to one or more interior spaces of the building. In this case, the air management system 100 may be or may include, for example, a heating, ventilation and air-conditioning (HVAC) system. The apparatus 110 may also be a vehicle, and the air duct 102 may serve for supplying air to the interior of the vehicle or for supplying air to the engine. In general, the apparatus 110 may include a ventilation system for supplying air (whether for breathing air or for machine use of the air) to an interior space 104 (in some aspects also referred to as indoor space or indoor environment). Air from the exterior space 105 may be moved through the air duct 102 into the interior space 104 of the apparatus 110, for example, by means of a fan 103 (e.g., a ventilation fan). Illustratively, the interior space 104 may be ventilated via the air duct 102 and air may be filtered by means of the filter 101. Thus, the filter 101 may serve to prevent a contamination of the interior space 104 and/or of the fan 103 (if the fan 103 is located behind the filter 101). If a non-self-regenerating filter is used, it may be necessary to change it regularly when the maximum filling level is reached. For this purpose, a filter receptacle with the possibility of replacing the filter 101 in the air duct 102 may be provided in the apparatus 110. In an apparatus with a heat exchanger for energy (re)recovery, the channels of the heat exchangers should also be protected from dust using one or more filters.

[0008] The air management system 100 may include one or more optical sensors, such as the optical sensor 114. The optical sensor 114 may be configured to detect a contamination of the filter 101 or at least a sensor signal indicating the contamination. The optical sensor 114 may be arranged at least partially (e.g., completely) within a filter pleat of the filter 101 (see, for example, description with reference to FIGS. 2A to 2C). The optical sensor 114 may be configured to provide a sensors signal representing light reflected from the filter 101 (e.g., representing an intensity of reflected light). The air management system 100 may include a control device 112. The air management system 100 may include an evaluation unit configured to receive the sensor signal from the optical sensor 114 and to generate an output signal which indicates a contamination of the filter 101. The evaluation unit may be part of the control device 112, may be part of the optical sensor 114, and/or may be another unit located inside or outside the air duct 102. The evaluation unit may be configured to receive the sensor signal wirelessly from the optical sensor 114 (hence the evaluation unit and the optical sensor 114 may include a wireless interface).

[0009] FIG. 2A to FIG. 2C show a filter arrangement 200 (in some aspects referred to as intelligent cabin filter, ICF) including the filter 101. The air management system 100 may include the filter arrangement 200. The filter 101 may include a filter frame 201 and a filter material 202 supported by the filter frame 201. The filter material 202 may form a surface through which transported air flows so that it is cleaned by the filter material 202 and contaminants are picked up by the filter material 202. The filter material 202 may be arranged to form a plurality of filter pleats. The optical sensor 114 may be arranged at a front side 203 (i.e., the side facing the exterior space 105) opposite a back side 205 (i.e., the side facing the interior space 104) facing the filter material 202.

[0010] The optical sensor 114 may be configured to radiate light (e.g., white light) onto the filter material 202. The optical sensor 114 may be configured to detect light reflected from the filter material 202. The optical sensor 114 may be configured to generate a sensor signal depending on the detected light. With reference to FIG. 2B, the optical sensor 114 may include a light emitting diode (LED) 210, such as a white-light emitting diode, configured to radiate light (e.g., white light) onto the filter material 202. The optical sensor 114 may include a light detector (e.g., an arrangement of one or more photo diodes) configured to detect light reflected from the filter material 202 (e.g., light reflected responsive to the radiation with white light). For example, the light detector may be an RGWB (red-green-blue-white) light detector, such as a micro electrical mechanical system (MEMS) light detector, configured to detect red light, green light, blue light, and white light.

[0011] The optical sensor 114 may be arranged (e.g., positioned) at least partially within a filter pleat of the plurality of filter pleats of the filter material 202.

[0012] With reference to FIG. 2C, the air flow 214 may include a plurality of particles 215, such as pollen, dust, mites, animal dandruff, volatile organic compounds, etc. The filter 101 may filter these particles 215 from the air flow 214 leading to a contamination 216 of the filter material 202 (e.g., in the filter pleats of the filter material 202). Each filter pleat of the plurality of filter pleats of the filter material 202 may be characterized by a height, h (which may be about 24 mm). The exemplary embodiment shown in FIG. 2C illustrates that the optical sensor 114 may be completely arranged within a filter pleat.

[0013] An exemplary contamination process is shown in FIG. 5A. The front side 203 of the filter material 202 is to the right and the back side 205 of the filter material 202 is to the left. The first diagram 501 corresponds to an initial phase of a clean filter (i.e., having a clogging level of 0%) which may be associated with a first color intensity (e.g., a red intensity, green intensity, blue intensity, and/or white intensity). Diagrams 501 to 505 show a progressing contamination (illustrated as balls) up to a completely contaminated filter (i.e., having a clogging level of 100%) in diagram 505. FIG. 5B illustratively shows the change of the color of the reflected light as a function of the contamination. Each diagram 510, 512, 514, 516 shows an intensity 520 as a function of a pressure drop 522 (in Pa) across the filter 101. The pressure drop may result from particle accumulation and, thus, contamination. Diagram 510 shows the detected white light intensity, diagram 512 shows the detected red light intensity, diagram 514 shows the detected green light intensity, and diagram 516 shows the detected blue light intensity for three different types of filters, namely a first filter type 530, a second filter type 532, and a third filter type 534. As an example, the first filter type 530 may be associated with an economy filter, the second filter type 532 may be associated with a premium filter type, and the third filter type 534 may be associated with a basic filter type. For example, the first filter type 530 may be a Bosch Eco filter having a dark blue color and an E08 filtration level, the second filter type 532 may be Bosch Premium T07 filter having a dark blue color and an E10 filtration level, and the third filter type 534 may be a Bosch White H07 filter having a white color and an E06 filtration level. It is noted that these are merely examples and that more than three filter types are possible.

[0014] FIG. 5C shows the overall intensity change 552 as a function of the filter clogging level 554 for the first filter type 530, the second filter type 532, and the third filter type 534. The evaluation unit may be configured to implement an algorithm configured to estimate the contamination (e.g., the clogging level) of the filter 101 using the sensor signal which represents one or more of the above described intensities and, thus, indicates the contamination of the filter 101. The evaluation unit may be configured to estimate a remaining lifetime of the filter 101 using the estimated contamination. The estimated contamination may include a percentage of contamination (with 100% as complete contamination in the sense of a clogging level) or a classification (e.g., as a value in a range from 0 to 3, from 0 to 5, from 0 to 10, etc.; or as an indication of "low contamination," "medium contamination," or "high contamination; or any other appropriate type of classification). The evaluation unit may be configured to output an output signal representing one or more of these estimations. The output signal may represent when to clean or replace the filter 101 and/or whether the filter 101 is to be cleaned/replaced. [0015] As shown in the diagrams of FIG. 5B and FIG. 5C, the relation between the filter contamination and the intensity of the respective color(s) may depend the filter type. For example, a person replacing the filter 101 may be required to enter a filter type of the newly installed filter. However, in the case that a wrong filter type is entered, the estimated contamination and, thus the estimated lifetime of the filter 101 may faulty (e.g., wrong). According to various embodiments, the evaluation unit may be configured to carry out an autodetection of the filter type as described in the following. The evaluation unit may be configured to determine a color of the filter material using a first sensor signal generated by the optical sensor. The first sensor signal may be associated with a clean filter (i.e., having a clogging level of 0%). The evaluation unit may be configured to receive one or more second sensor signals generated by the optical sensor successively in time temporally after the first sensor signal and may, for each second sensor signal, determine a difference between the respective second sensor signal and the first sensor signal. The evaluation unit may be configured to predict a filter type of the filter material using the determined differences. The evaluation unit may be configured to adjust a model (e.g., using the curves shown in diagrams 510 to 516) associated with the predicted filter type using the first sensor signal and the one or more second sensor signals. The evaluation unit may be configured to check whether the adjusted model fits and, thus, whether the filter type is predicted correctly. This may be carried out by determining a difference between a third sensor signal generated by the optical sensor temporally after the one or more second sensor signals with a sensor signal predicted by the adjusted model. The evaluation unit may be configured to, in the case that the difference between the third sensor signal and the predicted sensor signal is greater than a first predefined threshold value (i.e., if the predicted filter type seems to be wrong), select another filter type and repeat to detect sensor signals and to adjust the model correspondingly. The evaluation unit may be configured to, in the case that the difference between the third sensor signal and the predicted sensor signal is less than or equal to the first predefined threshold value (i.e., if the filter type seems to be predicted correctly), determine the predicted filter type as filter type of the filter material 202. The evaluation unit may be configured to continue to detect sensor second and third sensor signals, to adjust the model, and to determine the difference between the predicted sensor signal and the third sensor signal until the difference between the third sensor signal and the predicted sensor signal is equal to or less than a second predefined threshold value. Illustratively, the evaluation unit may carry out the above described auto-detection of the filter type until a predefined confidence level is reached. Then, the evaluation unit may set the auto-detected filter type (e.g., independent of the filter type initially entered).

[0016] With reference to FIG. 2C, the air management system 100 (e.g., the filter arrangement 200) may include a temperature sensor 122. The temperature sensor 122 may be configured to detect a temperature of the filter material 202 and/or a temperature in the surrounding of the filter material 202. The evaluation unit may be configured to receive the detected temperature from the temperature sensor 122 and may be configured to determine the contamination of the filter 101 and/or the remaining lifetime of the filter 101 using the detected temperature. The color spectrum of the reflected light may change due to the temperature of the filter material 202. Illustratively, the evaluation unit may employ the detected temperature to adjust a color shift induced by a temperature drift. This allows to correct the sensor drift at real-time thereby providing a more accurate evaluation of the filter clogging level.

[0017] With reference to FIG. 3, the air management system 100 may further include a particle sensor 106. The particle sensor 106 may be configured to detect a concentration of particles (e.g., in pg/m ³ ) within the air flow 214. The particle sensor 106 may be configured to detect particles having a size within a predetermined size range. The particle sensor 106 may be configured and arranged to detect and count particles within this predetermined size range. As an example, the predetermined size range may have a range from about 0.1 pm to about 100 pm. The particle sensor 106 may be configured to detect a respective particle concentration (also referred to in some aspects as a mass concentration rate of particles) for each sub-range of a plurality of sub-ranges within the predetermined size range. For example, the particle sensor 106 may have a particle size sub-range in a range of about 0.1 pm to about 1 pm. For example, the particle sensor 106 may have a particle size sub-range in a range from about 4 pm to about 10 pm. For example, the particle sensor 106 may have a particle size sub-range in a range above about 10 pm. The predetermined size range may have multiple non-continuous sub-ranges. The particle sensor 106 may include or may be a PM2.5 sensor. This PM2.5 sensor may be configured to detect (e.g., detect and count) particles in the predetermined size range (e.g., about 0.1 pm to about 100 pm). The particle sensor 106 may be configured to output the particle concentration at a predefined time interval (e.g., in a range from every approximately 2 seconds to approximately 5 seconds (e.g., every 2 seconds, every 3 seconds, every 4 seconds, or every 5 seconds)). As an illustrative example, the particle sensor 106 may be configured to output a mass concentration rate of up to 100 pg/m ³ of particles in the sub-range from about 0.1 pm to about 1 pm, a mass concentration rate of up to 150 pg/m ³ of particles in the subrange from about 4 pm to about 10 pm, and a mass concentration rate of up to 50 pg/m ³ of particles in the sub-range above about 10 pm (e.g., to about 100 pm).

[0018] The air management system 100 may include a gas sensor 120. The gas sensor 120 may be configured to detect an air quality of the air flow 214 which is supplied to the filter 101. The gas sensor 120 may be, for example, a volatile organic compound (VOC) sensor. The gas sensor 120 may be configured to detect volatile organic compounds (such as benzene, toluene, xylene, ethylbenzene). The gas sensor 120 may also be configured to detect gases, such as carbon dioxide and nitrogen dioxide. Illustratively, the data provided by the particle sensor 106 and the gas sensor 120 may represent the air quality of the air flow 214.

[0019] The control device 112 may be configured to provide instructions for controlling the air quality within the interior space 104. The control device 112 may be configured to provide the instructions in dependence on the output signal of the evaluation unit (which represents the contamination of the filter 101), the concentration of particles detected by the particle sensor 106, and/or the air quality of the air flow 214 detected by the gas sensor 120. An improved air quality within the interior space 104, as used herein, may be understood as a balance between fresh air (including oxygen) and recirculated air under the constraint of limited particles (e.g., dust, pollen, volatile organic compounds) and/or limited oxygen or nitrogen levels within the interior space 104. The particle sensor 106 and the gas sensor 120 may allow to characterize the type of particles (e.g., dust, gases, VOCs, etc.) within the air duct 102. According to various aspects, the gas sensor 120 is configured to detect VOCs as well as gases (e.g., CO2 and NO2). [0020] The air management system 100 may include another gas sensor configured to detect an air quality within the interior space 104. The other gas sensor may be configured to substantially similar to the gas sensor 120. The control device 112 may be configured to also consider the air quality within the interior space 104 when providing the instructions. Hence, the air quality (e.g., characterized by a concentration of CO2 and/or NO2) within the interior space 104 may be considered for providing fresh air and/or adjusting the recirculation mode (e.g., the degree of recirculation).

[0021] The instructions may be or may include instructions for controlling an amount of filtered air supplied to the interior space. Hence, the control device 112 may be configured to control an amount of air directed into the interior space 104. For example, the control device 112 may control a flow rate of the air flow 214. The control device 112 may be configured to control a degree of opening of a valve which fluidly connects the air duct 102 and the interior 104. The control device 112 may be configured to control a speed (e.g., revolutions per minute) of the fan 103 to increase or decrease the amount of air supplied into the interior space 104.

[0022] The instructions may be or may include instructions for notifying (e.g., instructing) a user located within the interior space 104 to control the air quality (e.g., by opening or closing a window of the interior space 104 (e.g., a vehicle window or a room window) and/or by changing an air recirculation mode). The instructions may include information regarding the sensed particle concentration and/or contamination of the filter 101, such as the classification of the degree of contamination (e.g., low/medium/high) and/or a classification of the particle concentration (e.g., low/medium/high). For example, in the case of a low particle concentration and a low clogging level of the filter 101, the user may be notified to open a window(s) (and optionally lowering the air recirculation). Optionally, a display device may be disposed in the interior space 104. The display device may include a display screen configured to display the instructions to the user (e.g., a driver and/or passenger in the case of a vehicle cabin), such as information the user about ways to improve air quality. The display device may be a screen fixed to the interior space 104 or may be a user terminal, such as a smartphone.

[0023] The instructions may be or may include instructions for controlling one or more windows to open or close and/or for changing the air recirculation mode. Hence, the control device 112 may be configured to automatically control or at least initiate the automatic control of the window(s) and/or the air recirculation mode.

[0024] As describe above, the evaluation unit may be configured to estimate the remaining lifetime of the filter 101. The instructions may be or may include instructions for notifying a user (e.g., on the display device and/or on the user terminal) to clean or replace the filter 101 and/or the filter material 202.

[0025] As an example, the apparatus 110 may be a vehicle driving through a polluted outdoor area (exterior space 105), such as a wildfire area, driving in stop-and-go-traffic etc. leading to a high concentration of particles (detected by particle sensor 106) and a high concentration of gases (detected by gas sensor 120). In this case, the air quality may be improved by closing the windows of the vehicle and by switching on or increasing the recirculation of the air within the interior space 104 (i.e., the vehicle cabin).

[0026] FIG. 4B shows a sensor arrangement 400. The sensor arrangement 400 may include a circuit board (e.g., a printed circuit board, PCB) 401 on which the optical sensor 114, the gas sensor 120, the temperature sensor 122, and/or the particle sensor 106 may be arranged. With reference to FIG. 4C, the circuit board 401, on which one or more of the sensor may be arranged, may be arranged at least partially (e.g., completely) within a filter pleat (e.g., having a filter pleat size 402, e.g., in the range from about 5 mm to about 7 mm) of the filter material 202. This allows to install the circuit board 401 with no additional adaption to the air duct 102 required. This also allows a direct measurement of accumulated particles and adsorbed gases on the filter material 202, thereby providing a more accurate sensing of the filter clogging level. An increased sensitivity towards dust accumulation may be achieved due to the close proximity of the optical sensor 114 to the surface of the filter 101.

[0027] The LED 210 of the optical sensor 114 may radiate (e.g., white) light 406 onto the contamination 216 (i.e., accumulated particles and/or adhered gases) of the filter material 202. The particle sensor 114 may be configured to detect the particle concentration of the contamination 216 within a field of view 408. The circuit board 401 may be coupled to an antenna 404 (e.g., a whip antenna and/or a PCB antenna) configured to wirelessly communicate (e.g., via a cloud) with the control device 112 to transmit the data detected by the one or more sensors arranged on the circuit board 401 to the control device 112. The evaluation unit may be, for example, part of the control device 112 or may be part of the circuit board 401 or arranged on the circuit board 401. With reference to FIG. 4D, the circuit board 401 may include a main board 410 and a sensor board 420 (see front view 430 of the sensor board 420). The main board 410 may include a microcontroller and/or wireless communication module 412 (e.g., on a first side). The main board 410 may include one or more compartments 414 (e.g., on a second side opposite the first side) including respective batteries (e.g., primary Li-ion coin cell batteries) for supplying energy to the main board 410 and/or the sensor module 420. Other options for powering the circuit board 401 are also possible such as thin-cell battery, secondary battery, and/or DC power supply from a dash board. A supercapacitor may be included into the compartment to support the handling of high peak currents at very low temperatures. However, a supercapacitor with diameter larger than the thickness of the coin-cell battery has to be located furthest away from the sensor board 420 to avoid negative interference of the optical sensing function. The sloped surface of the sensor board may allow light to flow around the circuit board 401.

[0028] FIG. 6 shows a flow diagram of a method 600. The method 600 may include radiating, by an optical sensor arranged at least partially within a filter pleat of a filter material, light onto the filter material within the filter pleat (in 602). The method 600 may include detecting light reflected from the filter material (in 604). The method 600 may include generating a sensor signal depending on the detected light (in 606). The method 600 may include generating an output signal depending on the sensor signal, wherein the output signal indicates a contamination of the filter material (in 608).

[0029] FIG. 7 shows a flow diagram of a method 700. The method 700 may include filtering an air flow using a filter material, wherein the filter material is arranged within a supply line for supplying the interior space (in 702). The method 700 may include determining a contamination of the filter material in accordance with the method 600. The method 700 may include detecting, by a particle sensor, a concentration of particles contained in the air flow which is supplied to the filter material, the particles having a size in a predetermined size range (in 704). The method 700 may include detecting, by a gas sensor, an air quality of the air flow which is supplied to the filter material (in 706). The method 700 may include providing instructions for controlling the air quality within the interior space in dependence on the determined contamination, the detected concentration of particles, and the detected air quality of the air flow (in 708).

[0030] In the following, exemplary embodiments are described:

[0031] Example 1 is a filter arrangement including: a filter material for filtering an air flow, wherein the filter material includes a plurality of filter pleats, an optical sensor arranged at least partially within a filter pleat of the plurality of filter pleats and configured to radiate light onto the filter material within the filter pleat, to detect light reflected from the filter material, and to generate a sensor signal depending on the detected light, and an evaluation unit configured to receive the sensor signal from the optical sensor and to generate an output signal depending on the received sensor signal, wherein the output signal indicates a contamination of the filter material.

[0032] In Example 2, the filter arrangement of Example 1 can optionally include that the sensor signal represents an intensity of the detected light, wherein, optionally, the sensor signal represents a red light intensity, a green light intensity, a blue light intensity, and a white light intensity of the detected light.

[0033] In Example 3, the filter arrangement of Example 1 or 2 can optionally include that the optical sensor is configured to radiate the filter material, to detect the reflected light, and to generate the sensor signal repeatedly at predefined intervals, thereby, generating a time curve of the detected light, and wherein the evaluation unit is configured to generate the output signal depending on the time curve of the detected light.

[0034] In Example 4, the filter arrangement of any one of Examples 1 to 3 can optionally further include: a temperature sensor configured to detect a temperature of the filter material and/or a temperature in the surrounding of the filter pleat and to provide the detected temperature to the evaluation unit, wherein the evaluation unit is configured to generate the output signal using the detected temperature.

[0035] In Example 5, the filter arrangement of any one of Examples 1 to 4 can optionally include that the sensor signal represents an intensity of the detected light, wherein, optionally, the intensity of the detected light is or includes a red light intensity, a green light intensity, a blue light intensity, and/or a white light intensity, wherein the evaluation unit is configured to: (a) determine a color of the filter material using a first sensor signal generated by the optical sensor, (b) for each second sensor signal of one or more second sensor signals generated by the optical sensor successively in time temporally after the first sensor signal, determine a difference between the respective second sensor signal and the first sensor signal, (c) predict a filter type of the filter material using the determined differences, (d) adjust a model associated with the predicted filter type using the first sensor signal and the one or more second sensor signals, (e) determine a difference between a third sensor signal generated by the optical sensor temporally after the one or more second sensor signals with a sensor signal predicted by the adjusted model, (f) in the case that the difference between the third sensor signal and the predicted sensor signal is greater than a first predefined threshold value, select another filter type and repeat (d) to (f), and in the case that the difference between the third sensor signal and the predicted sensor signal is less than or equal to the first predefined threshold value, determine the predicted filter type as filter type of the filter material.

[0036] In Example 6, the filter arrangement of Example 5 can optionally include that the evaluation unit is configured to repeat (b) to (f) until the difference between the third sensor signal and the predicted sensor signal is less than or equal to a second predefined threshold value, wherein the first predefined threshold value is greater than the second predefined threshold value.

[0037] Example 7 is an air management system including: a filter arrangement according to any one of Examples 1 to 6, an interior space (e.g., a vehicle cabin, a building, a room, several rooms, etc.), a first supply line for supplying the air flow to the filter material, a second supply line fluidly connected to the first supply line for supplying the air flow filtered by the filter material into the interior space, a particle sensor configured to detect a concentration of particles contained in the air flow which is supplied to the filter material via the first supply line, the particles having a size in a predetermined size range, a gas sensor configured to detect an air quality of the air flow which is supplied to the filter material via the first supply line, and a control device configured to provide instructions for controlling the air quality within the interior space in dependence on the output signal of the evaluation unit, the detected concentration of particles, and the detected air quality.

[0038] In Example 8, the air management system of Example 7 can optionally further include another gas sensor configured to detect an air quality within the interior space, wherein the control device is further configured to provide the instructions in dependence on the detected air quality within the interior space.

[0039] In Example 9, the air management system of Example 7 or 8 can optionally include that the instructions for controlling the air quality within the interior space include one or more instructions from the following group of instructions: instructions for controlling an amount of filtered air supplied to the interior space via the second supply line (e.g., by adjusting the speed of a ventilation fan located within the second supply line), instructions for notifying a user located within the interior space to control the air quality by opening or closing a window and/or by changing an air recirculation mode, instructions for controlling a window to open or close and/or for changing an air recirculation mode, instructions for notifying a user located within the interior space to replace the filter material.

[0040] Example 10 is a method for determining a contamination of a filter material, the method including: radiating, by an optical sensor arranged at least partially within a filter pleat of the filter material, light onto the filter material within the filter pleat, detecting light reflected from the filter material, generating a sensor signal depending on the detected light, generating an output signal depending on the sensor signal, wherein the output signal indicates a contamination of the filter material.

[0041] Example 11 is a method for controlling an air quality within an interior space, the method including: filtering an air flow using a filter material, wherein the filter material is arranged within a supply line for supplying the interior space, determining a contamination of the filter material in accordance with the method of Example 10, the contamination being represented by the output signal, detecting, by a particle sensor, a concentration of particles contained in the air flow which is supplied to the filter material, the particles having a size in a predetermined size range, detecting, by a gas sensor, an air quality of the air flow which is supplied to the filter material, and providing instructions for controlling the air quality within the interior space in dependence on the determined contamination, the detected concentration of particles, and the detected air quality of the air flow.