DE102020203314A1 - Air cleaning arrangement for a motor vehicle - Google Patents

Abstract

The invention relates to an air cleaning arrangement for a motor vehicle, comprising a duct section through which an air flow can flow and in which a first air cleaning unit (10) is arranged for removing particles from the air flow ) is designed as an electrostatic dust separator through which the air flow flows during operation, with an ionization zone in which an electric field is applied during operation, and with a separation zone downstream of the ionization zone in the direction of flow, in which electrostatically charged dusts are at least deposited in the ionization zone during operation deposit an oppositely charged separating plate (16).

Description

The invention relates to an air cleaning arrangement for a motor vehicle, comprising a duct section through which an air flow can flow and in which a first air cleaning unit is arranged for removing particles from the air flow.

Such air cleaning arrangements for motor vehicles are generally known. As a rule, they comprise a fan which generates an air flow through a duct which is typically provided with air guiding elements and which ends in particular in air outlets in the passenger compartment. The air flow can be a circulating or fresh air flow, with adjustment options for a combined air flow also regularly being available. In fresh air operation in particular, it is desirable to clean the air before it is blown into the passenger compartment so that dust, such as road dust, pollen, etc., does not get into the interior of the vehicle. Filters are used regularly for this, i. H. porous media through which the air stream flows and the dusts to be filtered out stick to their pores. In order to make such filters effective, the pores must be comparatively small, which, however, results in considerable flow resistance. This is disadvantageous for the interior air conditioning in motor vehicles, which is essentially based on convection and which regularly requires high air throughputs. In addition, such filters quickly clog, which further increases their air resistance.

So-called electrostatic separators, which are used in extractor hoods, are known from the field of house technology, in particular kitchen technology. In such fume hoods, air is sucked in and allowed to flow through an ionization zone. In the ionization zone there is a typically wire-shaped ionization electrode at high voltage potential, between which and at least one adjacent counter-electrode a high electric field is present. Gas molecules flowing through the ionization zone are partially ionized. In subsequent collisions with dust particles, they partially release their charge to them, so that the dust particles are electrically charged. Behind the ionization zone, the air stream flows through a separation zone in which separation plates, constructed like a plate capacitor, generate a further electric field between them, in which the charged dust particles are deflected onto one of the separation plates, depending on their charge, and adhere there. Such an extractor hood is known from DE 10 2017 204 061 A1 . An extractor hood, which in principle acts in the same way, is known from the DE 2 146 288 A .

Based on known air cleaning arrangements for motor vehicles, it is the object of the present invention to reduce their flow resistance in order to enable longer idle times with reduced energy consumption for the fan.

Preferred embodiments of the invention are the subject of the dependent claims.

This object is achieved in connection with the features of the preamble of claim 1 in that the first air cleaning unit is designed as an electrostatic dust collector through which the air flow flows during operation, with an ionization zone in which an electric field is present during operation, and with one of the Ionization zone in the downstream separation zone in which, during operation in the ionization zone, electrostatically charged dusts are deposited on at least one oppositely charged separation plate.

The core idea of the invention is first of all to use an electrostatic dust separator instead of a real filter as an air cleaning unit, as is basically known from the technically distant field of house and kitchen technology.

As provided in a preferred development of the invention, this first air cleaning unit, designed as an electrostatic dust separator, can be connected upstream in the flow direction of a second air cleaning unit, designed as a passive particle filter. This does not contradict the description of the problem explained above. Rather, the main part of the dust can be withdrawn from the air flow by means of the electrostatic dust separator, so that a filter arranged below clogs significantly less quickly and can be tailored for specific tasks, for example as an activated carbon filter to remove unpleasant odors. In any case, the total flow resistance of the air cleaning arrangement can turn out to be lower than previously known.

An essential reason that has hitherto prevented the person skilled in the art from using the generally known electrostatic dust separators in motor vehicles is their optimization for static use. The well-known extractor hoods using static dust separators are designed for long operating times with a continuous flow of air that is constant in strength. However, this static situation does not correspond to the problem in the motor vehicle. Here, due to different driving speeds and strongly varying blower outputs specified by the automatic air conditioning, are strong different air flow rates. If known electrostatic dust separators were used in isolation in motor vehicles, a cleaning effect that is strongly dependent on the air flow rate would result, which is not desirable.

In a further development of the invention, it is therefore provided that a particle quantity sensor, which is operatively connected to a control unit, is connected downstream of the first air cleaning unit in the direction of flow and the control unit is set up to control the electrical field present in the ionization and / or separation zone as a function of the signal from the particle quantity sensor . The electrode and separator plate distances can be optimized for a maximum air flow. The efficiency of the cleaning action is adapted as required by adapting the voltage applied in the ionization and / or separation zone. The cleaning efficiency required in each case is determined depending on the current cleaning result.

For example, an absolute need for cleaning can be determined on the basis of the air quality prevailing behind the first air cleaning unit. This should remain above a specified minimum quality. Such a minimum quality can be determined, for example, on the basis of a particle density within a measurement volume observed by the particle quantity sensor, through which the particle-laden air flows. The specific nature of the particle quantity sensor does not matter. Purely by way of example, however, optical, scatter-based particle density sensors may be mentioned as a possible embodiment.

The control unit can be set up to vary the strength of the electric field in the same direction as the variation of a particle amount measured by means of the particle amount sensor. In other words, in this embodiment, the strength of the electric field is to be increased when the amount of particles measured behind the first air cleaning unit increases.

As an alternative to this rather absolute approach, a more relative approach can be pursued in the control unit. In an alternative embodiment, it is provided that a reference particle quantity sensor, which is operatively connected to the control unit, is connected upstream of the first air cleaning unit in the direction of flow and the control unit is set up to generate the electrical field present in the ionization and / or separation zone as a function of a difference or ratio signal from To control particle quantity sensors. In particular, it can be provided that the control unit is set up to vary the strength of the electric field in the same direction as the variation of the difference or ratio signal. With this relative quality determination approach, the amount of particles in front of and behind the first air cleaning unit is measured and compared. This results in a measure of the current cleaning effectiveness, for example through the formation of differences or quotients. The control unit is then set up in such a way that it always readjusts the electric field in the ionization zone in such a way that a minimum cleaning effectiveness is achieved.

It has been found to be advantageous if a saw-blade-shaped ionization electrode is arranged in the ionization zone, which is acted upon by a voltage in relation to its surroundings, represented for example by a grounded housing. In particular, it can be provided that the electrodes penetrate the channel section transversely, the saw teeth of the saw-blade-shaped ionization electrode being aligned in the direction of flow. Particularly high fields are formed at the tooth tips of the saw teeth of an electrode shaped in this way, which benefit the intended ionization. In particular, such a shape allows a lower voltage application overall to achieve the required ionization.

To further increase efficiency, it has proven to be advantageous if the first air cleaning unit has a plurality of ionization and associated separation zones arranged parallel to one another. With such an arrangement, the overall air passage opening can be enlarged without excessively high voltages having to be applied to build up sufficiently high electrical fields.

Further details and advantages of the invention emerge from the following specific description and the drawings.

• 1 eine perspektivische Ansicht eines Einzelmoduls einer erfindungsgemäßen Luftreinigungseinrichtung,
• 2 eine Seitenansicht des Moduls von 1 sowie
• 3 eine Frontansicht einer erfindungsgemäßen Luftreinigungseinrichtung mit vier Modulen gemäß den 1 und 2.

Show it:

• 1 a perspective view of an individual module of an air cleaning device according to the invention,
• 2 a side view of the module of FIG. 1 and FIG
• 3 a front view of an air cleaning device according to the invention with four modules according to FIG 1 and 2 .

Identical reference symbols in the figures indicate identical or analogous elements.

In the 3 shown air purification device 10 comprises four individual modules 100 that are detailed in the 1 and 2 are shown, to which the further explanations are to be aligned. 1 shows such a thing Air purification module 100 in perspective view. 2 shows the module 100 in side view. The air purification device 10 or their individual modules 100 are particularly suitable as a series element for a conventional air filter. They act as a dust collector and thus reduce the particle load according to the directional arrow 12th sucked or blown air flow, so that the downstream air filter, not shown in the figures, clog less quickly.

On the input side, each module has 100 two sawtooth-shaped ionization electrodes 14th which are under high voltage of, for example, 10 to 20 kV in relation to the earthed environment. In particular, through the field tips on the sawtooth tips of the ionization electrodes 14, gas molecules in the air flow are ionized and give off their charge to them when they collide with dust particles in the air flow. The dust particles experience an electrostatic charge. The air flow then flows through a gap between two separation plates 16 which are electrically biased relative to one another in the manner of a plate capacitor. The voltage between the two separation plates 16 each module is also in the range of a few kV. For example, one of the plates opposite the grounded counter plate can have a high voltage of 7 kV. In the gap between the two separating plates 16 the electrostatically charged dust particles are placed on one of the separation plates according to their charge 16 distracted, where they stick and are thus permanently withdrawn from the air flow.

With the electrodes 14th , 16 is one in the 1 and 2 not shown and in 3 only based on their case 18th recognizable control unit connected. With this control unit there are also two in the 1 and 2 only schematically indicated particle quantity sensors 20th , 22nd tied together. In the illustrated embodiment, the particle quantity sensor is 20th downstream of the module outlet in the direction of flow. The reference particle quantity sensor 22nd is connected upstream of the module inlet in the direction of flow. In other embodiments, a single particulate amount sensor 20th downstream of the module output are sufficient. This measures the amount of particles in the air flow on the module outlet side and thus provides an absolute measure of the effectiveness of the air cleaning. With two particle quantity sensors, ie, as shown, with the particle quantity sensor 20th and a reference particle amount sensor 22nd , as an alternative or in addition, a relative determination of the air cleaning effectiveness can also be carried out.

The measurement data of the particle quantity sensors 20th , 22nd are sent to the control unit, which then evaluates the cleaning effectiveness according to predetermined rules stored in the memory and the voltage applied to the ionization electrodes 14th and / or the separation plates 16 is applied, corrected accordingly, in particular increased if the cleaning effectiveness is below a desirable level.

Of course, the embodiments discussed in the specific description and shown in the figures are only illustrative embodiments of the present invention. In the light of the disclosure here, a person skilled in the art is provided with a broad spectrum of possible variations. In particular, there is the specific way of measuring the amount of particles in the sensors 20th , 22nd freely selectable by a specialist. Also the specific choice of the voltage level to be applied to the electrodes 14th or the separation plates 16 is to be created, is to be adapted to the respective individual case. This also applies to the distance between the plates between the separation plates 16 which are decisive for the total throughput volume of the air flow.

List of reference symbols

10

Air purification unit

12th

Direction arrow

14th

ionization electrode

16

Separation plate

18th

Control housing

20th

Particle quantity sensor

22nd

Reference particle quantity sensor

100

Air purification module

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102017204061 A1 [0003]
• DE 2146288 A [0003]

Claims (9)

Air cleaning arrangement for a motor vehicle, comprising a duct section through which an air flow can flow, in which a first air cleaning unit (10) is arranged for removing particles from the air flow, characterized in that the first air cleaning unit (10) is designed as an air flow during operation A flow through, electrostatic dust separator with an ionization zone, in which an electric field is applied during operation, as well as a separation zone downstream of the ionization zone in the direction of flow, in which during operation in the ionization zone electrostatically charged dusts are deposited on at least one oppositely charged separation plate (16). Air cleaning arrangement according to Claim 1 , characterized in that a particle quantity sensor (20), which is operatively connected to a control unit, is connected downstream of the first air cleaning unit (10) in the direction of flow and the control unit is set up to control the electrical field present in the ionization and / or separation zone as a function of the signal from the particle quantity sensor ( 20) to control. Air cleaning arrangement according to Claim 2 , characterized in that the control unit is set up to vary the strength of the electric field in the same direction as variations in an amount of particles measured by means of the particle amount sensor (20). Air cleaning arrangement according to Claim 2 , characterized in that a reference particle quantity sensor (22), which is operatively connected to the control unit, is connected upstream of the first air cleaning unit (10) in the direction of flow and the control unit is set up to generate the electrical field present in the ionization and / or separation zone as a function of a difference or To control the ratio signal of the particle quantity sensors (20, 22). Air cleaning arrangement according to Claim 4 , characterized in that the control unit is set up to vary the strength of the electric field in the same direction as variations in the difference or ratio signal. Air cleaning arrangement according to one of the preceding claims, characterized in that a saw-blade-shaped ionization electrode (14), which is stressed with respect to its surroundings during operation, is arranged in the ionization zone. Air cleaning arrangement according to Claim 6 , characterized in that the electrodes penetrate the channel section transversely, the saw teeth of the saw-blade-shaped ionization electrode (14) being aligned in the direction of flow. Air cleaning arrangement according to one of the preceding claims, characterized in that the first air cleaning unit (10) has a plurality of ionization and associated separation zones arranged parallel to one another. Air cleaning arrangement according to one of the preceding claims, characterized in that the first air cleaning unit (10) is followed in the flow direction by a second air cleaning unit designed as a passive particle filter.

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