Air purification method and heating ventilation air conditioning system

Abstract

The invention relates to an air purification method and a heating ventilation air conditioning system. The invention relates to a heating, ventilation and air-conditioning system for a motor vehicle, comprising: an ionization device for generating a corona discharge field, said ionization device having at least one injection electrode having an electrical polarity and at least one counter electrode having an electrical polarity opposite to that of the injection electrode; a particulate filter for removing particulates from the airflow; and an air path that predetermines a flow direction of the air directed to the vehicle interior and that directs the air through the ionization device and the particulate filter, in which the ionization device is arranged upstream of the particulate filter in the air path. When the particle filter is configured to be multi-layered and has at least one dielectric layer and at least one electrically conductive layer, and when the HVAC system has an electrical connection for electrically connecting the respective electrically conductive layer to a mating potential of opposite electrical polarity with respect to the respective injection electrode, the particle filter is electrically connected to the respective injection electrode. The service life of the particle filter can be prolonged.

Description

Technical Field

[0001] The invention relates to a method for air purification in a heating, ventilation and air conditioning system for a motor vehicle. The invention also relates to a heating, ventilation and air conditioning system for a motor vehicle according to the preamble of claim 6. Background Art

[0002] Heating, ventilation and air conditioning systems are also often referred to as HVAC systems, where HVAC stands for heating, ventilation and air conditioning.

[0003] A generic HVAC system is known, for example, from EP 3 056 364 B1 and comprises an ionization device for generating a corona discharge field, the ionization device having at least one ejection electrode of electrical polarity and at least one counter electrode of electrical polarity opposite to the ejection electrode. The HVAC system also has a particle filter for removing particles from the air flow. Finally, the HVAC system has an air path, which predetermines the flow direction of the air to the interior of the vehicle and guides the air through the ionization device and the particle filter. The ionization device is arranged upstream of the particle filter in the air path. In the known HVAC system, the counter electrode is designed to be cylindrical and the ejection electrode is arranged concentrically with the cylindrical counter electrode and oriented parallel to its longitudinal axis.

[0004] Further HVAC systems using ionization are known from EP 3 488 933 A1, KR 10-2205159 B1, US 2021 / 0021 107 A1, WO 2020 / 263171 A1 and WO 2021 / 226639 A2.

[0005] Such HVAC systems are mainly used when the available space for the particle filter is small and at the same time a good filtering effect is desired with a large air volume requirement over a longer period of time. A good filtering effect can be achieved by a correspondingly small pore size in the particle filter. However, as the pore size decreases, the flow resistance of the particle filter increases. To compensate for this, the area through which the particle filter can flow can be correspondingly enlarged. However, the enlargement of the filter area is limited by the available space. In particular, in areas with a high fine dust load, a particle filter with a sufficiently small pore size can only achieve the desired air volume requirement or filtering effect in a short time, because the particle filter will quickly become clogged due to the increased load and the flow resistance will increase to an impermissible level. With the help of a particle filter that is electrostatically charged within the scope of its production, fine particles can be filtered out of the air flow even with large pores if these particles are ionized beforehand. The particles adhere to the charged filter material due to electrostatic attraction. The ionization of the particles can additionally increase the efficiency of the particle collection. The ionization of the particles is achieved using an ionization device. In this case, an electrostatic field, which is called a corona discharge field, is generated between the spray electrode and the counter electrode. The ejection electrode is preferably of negative polarity, while the counter electrode is of positive polarity or grounded. Corona discharge is generated at the sharp tip of the ejection electrode of negative polarity, which results in the generation of a large number of high-speed electrons moving in the direction of the opposite electrode. When these electrons hit the gas molecules in the air flow, either other electrons are separated or the electrons accumulate on the gas molecules. In the first case, new free electrons and positive gas ions are generated, and in the second case, negative gas ions are generated. This gas ionization works in principle even when the polarity is reversed, that is, when there is an ejection electrode of positive polarity and a counter electrode of negative polarity.

[0006] The particle charging is achieved by gas ions and begins as the particles enter the corona discharge space through which the jet flows. The charging of the particles occurs by the accumulation of gas ions on the particles when they collide with the particles. The charging process is achieved by field charging and diffusion charging.

[0007] However, it has been found that the initial electrostatic charge of the particle filter at the manufacturer's end is reduced due to the particle load, so that the filtering effect of the particle filter decreases sharply after a short service life. To compensate for this, the replacement interval of the particle filter can be significantly shortened, but this brings correspondingly high costs. Summary of the invention

[0008] The problem underlying the present invention is to specify an improved or at least another embodiment for an HVAC system of the type mentioned above or for an air purification method which is distinguished in particular by a good filtering effect with large air volumes over a long service life.

[0009] This problem is solved according to the invention by the subject matter of the independent claim. Advantageous embodiments are the subject matter of the dependent claims.

[0010] The general idea based on the air purification method for the HVAC system of a motor vehicle according to the present invention is to equip the particle filter with at least one conductive layer, which is set to a potential with opposite electrical polarity to the injection electrode, so that an electric field is generated between the ionization device and the particle filter during the operation of the ionization device. The particle filter can be polarized by the electric field between the ionization device and the particle filter. This electric field can therefore also be referred to as a polarization electric field. Through the targeted polarization of the particle filter, the static charge of the particle filter is regenerated to a certain extent. Therefore, a filtering effect that remains unchanged to a certain extent can be achieved even for a large amount of air within the prescribed service time or service life of the particle filter. The corresponding potential can be provided at the conductive layer of the particle filter, that is, the conductive layer is electrically contacted or electrically connected to the matching potential with opposite electrical polarity to the injection electrode.

[0011] According to an advantageous embodiment, it can be provided that the conductive layer is connected only to the matching potential until the electrostatic charge of the particle filter reaches a predetermined regeneration limit value. When the predetermined regeneration limit value is reached, the respective conductive layers of the particle filter are electrically separated from the matching potential. In addition or alternatively to this, it can be provided in another embodiment that the conductive layer is connected only to the matching potential until the predetermined regeneration time expires. When the predetermined regeneration time expires, the respective conductive layers of the particle filter are electrically separated from the matching potential. Therefore, the time is monitored in this case. For this reason, there is no need to monitor the regeneration of static electricity. These measures are based on the understanding that, after the particle filter is successfully polarized, the electrostatic charge of the particle filter that is then achieved is only slowly reduced or discharged during the operation of the HVAC system, that is, due to the particles filtered out from the air flow. Therefore, the particle filter regenerated by polarization behaves to a certain extent as a new particle filter that has been electrostatically charged during its production. The separation from the zero potential causes the electric field between the ionization device and the particle filter to no longer have to be established and maintained, so the ionization device requires less electrical power. Therefore, the HVAC system can be operated energy-efficiently.

[0012] During the generation of the electric field for polarizing the particle filter, the ionization device operates at a relatively increased electrical power. With increased electrical power, more ozone is generated in the air flow. As the respective electrically conductive layers separate from the matching potential, the electrical power of the ionization device decreases, so that less ozone is generated as a result, which is beneficial with regard to the ozone load in the vehicle interior.

[0013] According to an advantageous extended design scheme of the air purification method, it can be provided that the conductive layer is only separated from the matching potential until the polarization of the particle filter reaches a predetermined depolarization boundary value. In other words, the electrostatic charge of the particle filter is monitored. If the electrostatic charge is lower than the depolarization boundary value, the filter polarization is performed to restore the electrostatic charge. This restoration or polarization can be repeated as often as desired to a certain extent. When the predetermined depolarization boundary value is reached, the conductive layer of the particle filter is electrically connected to the matching potential again. Therefore, the repolarization or electrostatic charging of the particle filter is performed. In addition or alternatively to this, it can be provided in another embodiment that the conductive layer is only separated from the matching potential until the predetermined depolarization time expires. After the depolarization time expires, the conductive layer of the particle filter is electrically connected to the matching potential again. Therefore, the time is monitored in this case. There is no need to monitor polarization for this.

[0014] The regeneration time and / or depolarization time depends on the application provided for the respective particle filter, wherein in particular conditions such as the dimensioning of the particle filter, the filter effect to be achieved and / or the air volume and fine dust load at the respective location of use of the particle filter can be taken into account.

[0015] In principle, an embodiment can be advantageous in which the ejection electrode is positive and the counter electrode and the counter potential are negative. However, an embodiment is preferred in which the ejection electrode is negative and the counter electrode and the counter potential are positive. Ionization works particularly efficiently here.

[0016] According to an advantageous embodiment, it can be provided that the counter electrode is electrically connected, in particular permanently, to a counter potential and that the electrically conductive layer of the particle filter is electrically connected to the counter electrode in order to electrically connect the electrically conductive layer to the counter potential. This embodiment is particularly easy to implement.

[0017] The general idea underlying the HVAC system according to the invention is to provide at least one electrically conductive layer in the particle filter and to configure it in such a way that it can be electrically connected to a matching potential of opposite electrical polarity to the injection electrode. To this end, the HVAC system is equipped with an electrical connection, which is configured in such a way that the respective electrically conductive layer can be electrically connected or contacted with the matching potential by means of the electrical connection. In the simplest case, this can be achieved by means of a grounding cable, which is electrically connected to the zero potential of the ionization device.

[0018] In this context, "configured" is synonymous with "designed" and / or "programmed", so that the expression "configured so that" is synonymous with the expression "designed and / or programmed so that".

[0019] An embodiment is advantageous in which the electrical connection is designed to be switchable. As a result, the respective electrically conductive layer can be connected to or disconnected from the matching potential as required. Thus, during operation of the ionization device, the particle filter can be polarized in the electrically conductive layer that is electrically connected to the matching potential in order to regenerate its electrostatic charge. When the electrostatic charge is sufficient, further polarization can be terminated by disconnecting the connection to the matching potential in order to save electrical energy and reduce the generation of ozone. The switchability of the connection can be achieved, for example, by means of an electromechanical switch or an electronic switch.

[0020] An embodiment is particularly advantageous in which the HVAC system has a control device which is configured to carry out the aforementioned air purification method during operation of the HVAC system. In other words, the control device controls the controllable components of the HVAC system, namely in particular the ionization device and the switchable connection, to carry out the aforementioned air purification method.

[0021] According to an advantageous embodiment, the spray electrode can have a plurality of needles which are oriented in the direction of flow of the air or against the direction of flow of the air. The needles protrude from the needle holder in the direction of flow or against the direction of flow. The needles can extend obliquely or parallel to the direction of flow. The respective spray electrode and the associated counter electrode are arranged in the air path at a distance from each other transversely to the direction of flow of the air.

[0022] According to an advantageous embodiment, the respective spray electrode can have a plurality of outflow-side needles which extend in the flow direction and point toward the particle filter. When the outflow-side needles point toward the particle filter, the tips of the needles face toward the particle filter.

[0023] In another advantageous embodiment, the respective ejection electrode can have a plurality of inflow-side needles which extend counter to the flow direction or point away from the particle filter. The tips of the needles thus face away from the particle filter. Although an embodiment in which the respective ejection electrode has inflow-side needles and outflow-side needles is preferred, an embodiment in which there are no inflow-side needles or outflow-side needles is also possible.

[0024] According to an advantageous embodiment, the respective counter-electrodes can be designed as plates, preferably as flat plates. The plate-shaped counter-electrodes can extend parallel to the respective ejection electrodes. The respective plates are flat, i.e., have a plate thickness that is smaller than the plate length and plate width. The respective plates are, for example, arranged in the air flow so that the plate width extends parallel to the flow direction of the air, while the plate length and plate thickness extend transversely to the flow direction of the air, respectively. Therefore, air flows in only at the narrow edge of the plate-shaped counter-electrodes. It can be additionally or alternatively provided that the respective ejection electrodes and the subordinate counter-electrodes extend straightly and preferably transversely to the flow direction of the air, respectively. A particularly effective corona discharge field can be generated by this structural form, so that the particles carried in the air flow can be ionized particularly effectively. In addition, this configuration is constructed smaller with respect to the flow direction of the air.

[0025] The dielectric layer of the particle filter can be designed as a particle filter layer, which has a nonwoven or is composed of a nonwoven. The nonwoven is usually made of plastic and is therefore dielectric. The nonwoven can be made in particular as a so-called meltblown fabric. The particle filter layer defines the pore size of the particle filter and is impermeable to particles whose size is larger than the pore size.

[0026] In another embodiment, the electrically conductive layer of the particle filter can be designed as an adsorption filter layer, which has activated carbon particles or consists of activated carbon particles. Since the electrically conductive activated carbon particles are attached to each other, the adsorption filter layer is electrically conductive as a whole and can be used to form a polarization electric field through their grounding. The adsorption filter layer filters by adsorption, wherein the adsorption filter layer has an adsorption effect on gas molecules in particular. The activated carbon particles can be attached to the nonwoven layer or held between two nonwoven layers.

[0027] Alternatively, the electrically conductive layer of the particle filter can be designed as a grid structure, which has or consists of electrically conductive wires or electrically conductive fibers or electrically conductive threads. Unlike a particle filter layer or an adsorption filter layer, the grid structure has no significant filtering effect.

[0028] An embodiment is expedient in which the respective dielectric layer is placed on the electrically conductive layer and is in contact with it. In particular, the electrically conductive layer extends over the entire extension of the respective dielectric layer. By means of this measure, the electric field generated by the grounding of the electrically conductive layer acts as far as the dielectric layer, so that in particular the dielectric layer can be polarized or electrostatically charged.

[0029] In this context, a configuration has proven to be particularly advantageous in which the respective dielectric layer is arranged upstream of the respective electrically conductive layer in the particle filter. This has the effect that the electrons and / or ions transported in the electric field strike the dielectric layer on the way to the electrically conductive layer and adhere there and bring about the desired polarization.

[0030] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated description of the figures with the aid of the drawings.

[0031] It goes without saying that the features mentioned above and those to be explained below can be used not only in the respectively described combination but also in other combinations or alone without departing from the scope of the invention defined by the claims. The individually marked above-mentioned and below-mentioned components of a superordinate unit, such as an apparatus, a device or an arrangement, can form individual components or parts of this unit or regions or sections of this unit that constitute the whole, even if this is shown differently in the drawings.

[0032] Preferred exemplary 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the figure:

[0034] Figure 1 A simplified, circuit diagram-like schematic diagram of an HVAC system with a particle filter and an ionization device is schematically shown;

[0035] Figure 2 Schematic diagram of the particle filter according to Figure 1 A simplified cross section of the cutting line II in FIG.

[0036] Figure 3a and Figure 3b Schematically shows the ionization device in the region of the electrode pair in different states according to Figure 1 A simplified cross section of the section line III in FIG.

[0037] Figure 4 in accordance with Figure 3a and Figure 3b The viewing direction IV in FIG. 1 schematically shows Figure 3a and Figure 3b Simplified side view of an electrode pair. DETAILED DESCRIPTION

[0038] according to Figure 1 The HVAC system 1 of the motor vehicle 2, which is not shown, and which is only partially shown here, comprises an ionization device 3, by means of which a voltage can be generated. Figure 3aand Figure 3b The corona discharge field 4 is shown by a dashed line in FIG. For this purpose, the ionization device 3 has at least one electrode pair 5, which has a spray electrode 6 with a negative or positive electrical polarity and a counter electrode 7 with an opposite electrical polarity. Figure 1 In the example of FIG. 4 , four such electrode pairs 5 are shown. Obviously, in another embodiment, more than two, in particular three or more such electrode pairs 5 can also be used. In particular, n spray electrodes 6 and n+1 counter electrodes 7 can be provided in the ionization device 3, so that each spray electrode 6 is arranged transversely to the flow direction 11 between two counter electrodes 7. Figure 3a and Figure 3b In order to simplify the illustration, only one injection electrode 6 is shown in each case.

[0039] The respective ejection electrodes 6, which can also be referred to as emitter electrodes, are connected in a suitable manner to a high-voltage power supply 8, which provides, for example, a DC voltage in the range of 5 kV to 10 kV, preferably about 7 kV. The counter electrode 7 is electrically connected in a suitable manner to a counter potential 9 of opposite electrical polarity to the ejection electrode 6. In the preferred case shown here, the respective ejection electrode 6 is of negative polarity and the subordinate counter electrode 7 is of positive polarity. Therefore, the counter potential 9 is also of positive polarity, which is Figure 1 and Figure 2 In the figure, it is simplified by using the zero potential symbol.

[0040] The HVAC system 1 also has a particle filter 10, which is configured to remove particles from an air flow 28, which is shown in the figure by wavy arrows. During operation of the HVAC system 1, the air flow 28 has a flow direction 11, which is shown in the figure by arrows. An air path 12 is formed in the HVAC system 1, which air path is Figures 1 to 4 1 is indicated by a dash-dotted line. The air path 12 predetermines the flow direction 11 of the air. The air path 12 leads through the ionization device 3 and the particle filter 10. It should be noted that the ionization device 3 is arranged upstream of the particle filter 10 in the air path 12 with respect to the air flow direction 11. The air path 12 leads the air to a vehicle interior 29 of the vehicle 2, which is not shown in detail. The air can be fresh air from the surroundings of the vehicle 2 or recirculated air from the vehicle interior 29 or a mixture of fresh air and recirculated air.

[0041] according to Figure 1 and Figure 2The particle filter 10 is configured in multiple layers, so that the particle filter has at least one dielectric layer 13 and at least one electrically conductive layer 14. The HVAC system 1 is also equipped with an electrical connection 15, which is used to electrically connect the respective electrically conductive layer 14 to the matching potential 9. The electrical connection 15 can be arranged according to Figure 1 According to an advantageous embodiment, the connection 15 is designed to be switchable. For this purpose, for example, it can include a switch 16, by means of which the electrical contact between the electrically conductive layer 14 and the matching potential 9 can be opened and closed as required. Figure 1 In the example of FIG. 1 , the electrically conductive layer 14 can be electrically connected to the respective mating electrode 7 and the mating potential 9 via a connection 15 and a switch 16 .

[0042] according to Figure 1 The HVAC system 1 may also be equipped with a control device 17, which can be connected to the high voltage power supply 8 and the switch 16 in a suitable manner, for example via a control line 18. The control device 17 may be configured to perform the air purification method described in more detail below.

[0043] According to the air purification method, the particle-contaminated air flow 28 is first guided through the ionization device 3 and then through the multi-layer particle filter 10 according to the air path 12. Here, the ionization device 3 generates a corona discharge field 4 by means of the respective injection electrode 6 and the subordinate counter electrode 7. The air flow 28 to be purified is guided through the corona discharge field 4. The particles carried in the air flow 28 are ionized in the corona discharge field 4. In addition, for the air purification method, the conductive layer 14 is also electrically connected or electrically contacted with the counter potential 9 via the electrical connection 15, so that an electric field 19 is generated between the ionization device 3 and the particle filter 10, and the electric field is Figure 3a , Figure 3b and Figure 4 1 is indicated by a dashed line and is referred to below as a polarization field 19 . This polarization field 19 enables a polarization of the particle filter 10 , which ultimately leads to an electrostatic charging of the particle filter 10 .

[0044] The air purification method can be configured to enable the conductive layer 14 to be connected to the matching potential 9 only until the polarization of the particle filter 10 reaches a predetermined regeneration boundary value and / or until the predetermined regeneration time expires. When the predetermined regeneration boundary value is reached or when the predetermined regeneration time expires, the conductive layer 14 of the particle filter 10 is electrically separated from the matching potential 9. This can be achieved by disconnecting the switch 16. During the filtering operation, the static charge of the particle filter 10 is reduced again. In addition, the air purification method can be configured to enable the conductive layer 14 to be separated from the matching potential 9 only until the polarization of the particle filter 10 is reached, that is, the static charge of the particle filter reaches a predetermined depolarization boundary value and / or until the predetermined depolarization time expires. When the predetermined depolarization boundary value is reached or when the depolarization time expires, the conductive layer 14 of the particle filter 10 is electrically connected to the matching potential 9 again. This can be achieved, for example, by closing the switch 16. In particular, provision can be made here for the first electrical connection of the electrically conductive layer 14 to the matching potential 9 to take place only when the electrostatic charge of the particle filter 10 has reached a predetermined depolarization limit value and / or when a predetermined depolarization time has expired.

[0045] according to Figure 1 , Figure 3a , Figure 3b and Figure 4 , each ejection electrode 6 can have a plurality of needles 20 which protrude from a needle holder 23 and have a needle tip 24 or a tip 24 at its end away from the needle holder 23, which is only Figure 3a , Figure 3b and Figure 4 In the respective electrode pairs 5, the ejection electrode 6 and the counter electrode 7 are spaced apart from each other transversely to the flow direction 11, so that the air path 12 can guide the air flow 28 between the ejection electrode 6 and the counter electrode 7. If a plurality of electrode pairs 5 are adjacent transversely to the flow direction 11, the ejection electrode 6 can be arranged between two counter electrodes 7 and cooperate with the two counter electrodes 7 to form the corona discharge field 4.

[0046] The needle 20 of each ejection electrode 6 is arranged in accordance with Figure 3a , Figure 3b and Figure 4 The needles 20 may extend parallel to the flow direction 11. They thus protrude from the needle holder 23 in the direction of or against the flow direction 11. Figure 1 , Figure 3a and Figure 3b The needle is designed to be pin-shaped. Figure 4 Designed into cone or pyramid shape. Also can think of sheet-like needle 20, they gradually become pointed to form needle tip 24.

[0047] according to Figure 1 , Figure 3a, Figure 3b and Figure 4 , the respective ejection electrode 6 can have a plurality of needles 21 on the outflow side, which point toward the particle filter 10. In other words, the needles 21 on the outflow side protrude from the needle holder 23 in the direction toward the particle filter 10. Therefore, the tips 24 of the needles 21 on the outflow side face toward the particle filter 10. Preferably, the needles 21 on the outflow side extend parallel to the flow direction 11 of the air.

[0048] In addition or alternatively to the needles 21 on the outflow side, the respective spray electrode 6 can have a plurality of needles 22 on the inflow side, which point away from the particle filter 10. In other words, the needles 22 on the inflow side protrude from the needle holder 23, pointing away from the particle filter 10. The tips 24 of these needles 22 on the inflow side also face away from the particle filter 10. The needles 22 on the inflow side can extend appropriately parallel to the flow direction 11 of the air. The needles 22 on the inflow side are mainly used to generate the corona discharge field 4.

[0049] When a high voltage potential is applied to the ejection electrode 6 and according to Figure 3a When the switch 16 is turned off, a corona discharge field 4 is formed between the ejection electrode 6 and the counter electrode 7, i.e., between the tip 24 of the needle 21 and the counter electrode 7. This electric field, i.e., the corona discharge field 4, is mainly responsible for the electrostatic charging of the particles in the air flow 28. When a high voltage potential is applied to the ejection electrode 6 and the Figure 3b When the switch 16 is turned on and connected to the counter electrode 7, the corona discharge field 4 is mainly formed between the ejection electrode 6 and the counter electrode 7, that is, between the tips 24 of the needles 21 and 22 and the counter electrode 7, wherein an electric field 19 is additionally formed between the tips 24 of the needles 21 on the outflow side and the filter element 10, mainly the filter element layer 14. Here, the electric field 19 is mainly used for polarization or regeneration of the layer 13 of the filter element 10. When the switch 16 is turned on, the intensity of the electric field 19 is very high, and when the switch 16 is turned off, the electric field strength of the electric field 19 is very low.

[0050] The ejection electrode 6 may be held at a dielectric high voltage insulator which is a component of the HVAC system. Figure 1 The housing 30 shown is part of or a separate unit arranged in the housing 30 of the HVAC system 1. These insulators are Figures 1 to 4 Different shapes and different dielectric materials can be used to produce the high-voltage insulator. The high-voltage insulator serves to electrically insulate the injection electrode 6 from the counter electrode 7 with the opposite potential or from the ground or from the grounded housing 30 of the HVAC system 1 or from the grounded vehicle component or from the grounded vehicle 2.

[0051] The respective counter electrode 7 can be suitably configured as a plate, which extends parallel to the respective spray electrode 6. In this case, the respective counter electrode 7 can be designed flat, i.e., as a flat plate. The spray electrode 6 and the counter electrode 7 can extend straight and parallel to each other and in particular perpendicular to the flow direction 11 of the air. The respective needle holder 23 is configured, for example, as a straight rod. According to Figure 1 The counter electrodes 7 designed as flat plates extend parallel to one another and in a plane parallel to the flow direction 11 of the air flow 28. The counter electrodes 7 are therefore spaced apart from one another transversely to the flow direction.

[0052] according to Figure 2 The dielectric layer 13 of the particle filter 10 can be designed as a particle filter layer, which is formed by at least one nonwoven fabric. In contrast, the electrically conductive layer 14 of the particle filter 10 can be designed as an adsorption filter layer 26 with activated carbon particles. In addition or as an alternative to such an adsorption filter layer 26, it can also be provided that the electrically conductive layer 14 of the particle filter 10 is configured as a grid structure 27, which is formed by means of electrically conductive wires or fibers or threads.

[0053] The electrically conductive layer 14 is placed on the dielectric layer 13 within the particle filter 10 and is in contact with it. Preferably, the contact is made over the largest possible area. For this purpose, the electrically conductive layer 14 can extend over the entire outflow side or inflow side of the dielectric layer 13. Figure 2 In the example of , the particle filter 10 is pleated, wherein the electrically conductive layer 14 follows the pleating of the dielectric layer 13 and is likewise pleated. The configuration shown here is preferred, in which the respective dielectric layer 13 is arranged upstream of the respective electrically conductive layer 14 within the particle filter 10. However, in principle, an embodiment is also conceivable in which the respective dielectric layer 13 is arranged downstream of the respective electrically conductive layer 14 within the particle filter 10.

[0054] It is obvious that the HVAC system 1 may also have a heater for heating the air flow 28 and a cooler for cooling and drying the air flow 28 .

Claims

1. An air purification method for a heating, ventilation and air conditioning system (HVAC system) (1) of a motor vehicle (2), wherein: The particle-contaminated air flow (28) first flows through the ionization device (3) and then through the multi-layer particle filter (10), wherein: The particle filter (10) comprises at least one dielectric layer (13) and at least one electrically conductive layer (14). - the ionization device (3) generates a corona discharge field (4) by means of at least one spray electrode (6) of electrical polarity and at least one counter electrode (7) of electrical polarity opposite to the spray electrode, - directing the air flow (28) to be purified through the corona discharge field (4), thereby ionizing the entrained particles, - electrically connecting the electrically conductive layer (14) of the particle filter (10) to a matching potential (9) of opposite electrical polarity to the injection electrode (6) in order to generate an electric field (19) between the ionization device (3) and the particle filter (10) for polarizing the particle filter (10).

2. The air purification method according to claim 1, characterized in that: - connecting the electrically conductive layer (14) only to the matching potential until the polarization of the particle filter (10) reaches a predetermined regeneration limit value or until a predetermined regeneration time has expired, - when the predetermined regeneration limit value is reached or when the regeneration time has expired, the electrically conductive layer (14) of the particle filter (10) is electrically separated from the matching potential (9).

3. The air purification method according to claim 2, characterized in that: - the electrically conductive layer (14) is separated from the matching potential (9) only until the polarization of the particle filter (10) reaches a predetermined depolarization limit value or until a predetermined depolarization time has expired, When the predetermined depolarization limit value is reached or when the depolarization time has expired, the electrically conductive layer (14) of the particle filter (10) is electrically connected again to the matching potential (9).

4. The air purification method according to any one of claims 1 to 3, characterized in that: - The ejection electrode (6) is set to negative polarity, and the matching electrode (7) and the matching potential (9) are set to positive polarity.

5. The air purification method according to any one of claims 1 to 4, characterized in that: - the matching electrode (7) is electrically connected to the matching potential (9), - electrically connecting the electrically conductive layer (14) of the particle filter (10) to the counter electrode (7) in order to electrically connect the electrically conductive layer (14) to the counter potential (9).

6. A heating, ventilation and air conditioning system (HVAC system) (1) for a motor vehicle (2), the HVAC system comprising: - an ionization device (3) for generating a corona discharge field (4), the ionization device comprising at least one ejection electrode (6) of electrical polarity and at least one counter electrode (7) of electrical polarity opposite to the ejection electrode (6), - a particle filter (10) for removing particles from the air flow (28), an air path (12) which specifies a flow direction (11) of the air which is directed to the vehicle interior (29) and which directs the air through the ionization device (3) and the particle filter (10), - in, The ionization device (3) is arranged upstream of the particle filter (10) in the air path (12), It is characterized in that - the particle filter (10) is configured in multilayer and has at least one dielectric layer (13) and at least one electrically conductive layer (14), The HVAC system (1) has an electrical connection (15) for electrically connecting the respective electrically conductive layer (14) to a matching potential (9) of opposite electrical polarity relative to the injection electrode (6).

7. The HVAC system (1) according to claim 6, characterized in that The electrical connection (15) is designed to be switchable, so that the respective electrically conductive layer (14) can be connected to or disconnected from the matching potential (9) as required.

8. The HVAC system (1) according to claim 6 or 7, characterized in that The HVAC system (1) has a control device (17) which is configured to perform the air purification method according to any one of claims 1 to 5.

9. The HVAC system (1) according to any one of claims 6 to 8, characterized in that - the respective spray electrode (6) has a plurality of needles (20) which are oriented in the direction of flow (11) of the air or against the direction of flow (11) of the air, The respective spray electrode (6) and the associated counter electrode (7) are spaced apart from one another transversely to the flow direction (11) of the air.

10. The HVAC system (1) according to claim 9, characterized in that The respective spray electrode (6) has a plurality of outflow-side needles (21) which point toward the particle filter (10) so that the tips (24) of the outflow-side needles (21) face toward the particle filter (10).

11. The HVAC system (1) according to claim 9 or 10, characterized in that The respective spray electrode (6) has a plurality of inflow-side needles (22) which point away from the particle filter (10) such that the tips (24) of the inflow-side needles (22) face away from the particle filter (10).

12. The HVAC system (1) according to any one of claims 6 to 11, characterized in that - the respective counter electrode (7) is designed, in particular, as a flat plate which extends parallel to the respective spray electrode (6), and / or The respective spray electrode ( 6 ) and the associated counter electrode ( 7 ) each extend straight and preferably transversely to the flow direction ( 11 ) of the air.

13. The HVAC system (1) according to any one of claims 6 to 12, characterized in that The dielectric layer (13) of the particle filter (10) is designed as a particle filter layer (25) which comprises a nonwoven fabric or consists of a nonwoven fabric.

14. The HVAC system (1) according to any one of claims 6 to 13, characterized in that The electrically conductive layer (14) of the particle filter (10) is designed as an adsorption filter layer (26) which comprises activated carbon particles or consists of activated carbon particles.

15. The HVAC system (1) according to any one of claims 6 to 13, characterized in that The electrically conductive layer (14) of the particle filter (10) is designed as a grid structure (27) which comprises or consists of electrically conductive wires, electrically conductive fibers or electrically conductive threads.

16. The HVAC system (1) according to any one of claims 6 to 15, characterized in that - The respective dielectric layer (13) is placed on the electrically conductive layer (14) and is in contact therewith.

17. The HVAC system (1) according to any one of claims 6 to 16, characterized in that In the particle filter (10), the respective dielectric layer (13) is arranged upstream of the respective electrically conductive layer (14).

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