WO2019020373A1

WO2019020373A1 - Particle sensor and method for producing same

Info

Publication number: WO2019020373A1
Application number: PCT/EP2018/068764
Authority: WO
Inventors: Radoslav Rusanov; Oliver Krayl
Original assignee: Robert Bosch Gmbh
Priority date: 2017-07-25
Filing date: 2018-07-11
Publication date: 2019-01-31
Also published as: DE102017212789A1; EP3658888A1; KR20200028957A

Abstract

The invention relates to a particle sensor (100; 100a; 100b; 100c; 100d; 100e) comprising a main body (110), a particle charging device (120) for charging particles in a fluid flow (A1) flowing over a first surface (110a) of the main body (110), wherein the particle charging device (120) has a high-voltage electrode (122) for generating a corona discharge (123) and a counter electrode (124), and the counter electrode (124) is designed and positioned to deflect charged portions of the fluid flow (A1).

Description

description

title

Particle sensor and manufacturing method for this state of the art

The invention relates to a particle sensor having a base body and a particle charging device for charging particles in a fluid flow flowing over a first surface of the base body, wherein the

Particle charging a arranged in the region of the first surface

High voltage electrode for generating a corona discharge has.

The invention further relates to a method for producing such a particle sensor.

WO 2013/125181 A1 discloses a particle sensor for use in

Cars known. The known particle sensor has a complex layer structure with a multiplicity of individual layers of comparatively complex geometry.

Disclosure of the invention

Accordingly, it is an object of the present invention to improve a particle sensor of the type mentioned in that it has a simpler structure and is inexpensive to manufacture.

This object is achieved by the particle sensor according to claim 1. The particle sensor comprises a main body and a particle charging device for charging particles in a over a first surface of the

Base body flowing fluid flow, wherein the particle charging device arranged in the region of the first surface of the high-voltage electrode for Producing a corona discharge. Further, a counter electrode to the high voltage electrode is provided, wherein the counter electrode is configured and arranged to deflect charged particles of the fluid flow. Under a counter electrode is present one of the

High voltage electrode different electrode understood, which is acted upon by a respect to the high voltage electrode different electrical potential. For example, the counter electrode to the

High voltage electrode to be placed on a reference potential or be firmly connected to a reference potential having circuit node. In further embodiments, the high voltage electrode may have a positive or negative electrical potential over the

Be counteracted electrode. According to the invention, the counter electrode advantageously fulfills a dual function.

First, it forms the electrical counter electrode to the

High voltage electrode and thus contributes to the generation of the corona discharge. Secondly, the counterelectrode simultaneously forms a so-called trap electrode, which makes it possible to use the corona discharge charged particles of the

Distracting fluid flow. For this purpose, the invention provides that the

Counter electrode is formed and arranged with respect to the high voltage electrode, that it can also fulfill the function of the trap electrode. The counterelectrode according to the invention can therefore also be referred to as a combined "trap and corona counterelectrode" and enables a particularly efficient production of the particle sensor as well as an overall cost-effective

Construction. Advantageously, in some embodiments, only one electrical connection for contacting the counter electrode is required, whereas in conventional systems with counter electrode and separate trap electrode two different electrical connections for these electrodes are required.

For example, the fluid stream may be an exhaust gas stream of an internal combustion engine of a motor vehicle. For example, the particles may be soot particles, such as those produced as part of combustion of fuel by an internal combustion engine. In a preferred embodiment, the base body has a substrate element or is formed from a substrate element. The main body is particularly preferred formed a substantially planar ceramic substrate. By way of example, the basic body can have a substantially cuboidal basic shape with a width and a length, wherein a height dimension is comparatively small with respect to the width and the length. More preferably, the first surface is an outer surface of the main body.

The corona discharge provided by the present invention in the particle sensor allows for charging of particles or particles in general, e.g. also of gases, from the fluid flow or exhaust gas flow in a space around the

High voltage electrode. This will be on the one hand particles directly at

Flowed through a space located in the region of the first surface in which the corona discharge takes place. On the other hand, particles are charged via charged particles of the gas or exhaust gas flow, wherein the gas or. Exhaust gas flow was charged directly when flowing through the room in the area of the high voltage electrode. This improves the overall

Effectiveness of charging. In a preferred embodiment, the high voltage electrode has at least one needle-shaped electrode or tip. In an advantageous embodiment, it is provided that the

High voltage electrode at least partially, in particular directly, is arranged on the first surface of the base body, wherein the counter electrode at least partially, in particular directly, on the first surface of the

Basic body is arranged. In one embodiment, a particularly small-sized configuration results when the high-voltage electrode and the counter electrode, in particular completely, are arranged on the first surface of the base body.

A "direct" arrangement of the relevant electrode on the first surface of the base body which can be provided in some embodiments is understood here to mean that the relevant electrode has a substantially flat contact area with the first surface or covers the first surface in contact, for example in the form of a coating ,

According to further embodiments, other arrangements of the relevant electrode (s) on the first surface of the base body are conceivable, in which the relevant electrode is arranged for example in the region of the first surface, but not directly on it.

In a further embodiment, it is provided that a voltage source for supply, so electrical power supply, the

Particle charging device is provided, wherein a first terminal of the voltage source is electrically conductively connected to the high voltage electrode, and wherein the counter electrode is electrically conductive via a

Resistor element is connected to a second terminal of the voltage source. The provision of the resistance element, which according to preferred embodiments can be a substantially purely resistive resistance element, advantageously affords degrees of freedom with regard to an operation of the particle sensor. For example, by selecting the resistance value of the resistive element and the other operating parameters (e.g., electrical voltage delivered from the voltage source), the electrical potential of the counterelectrode may be affected. Since these embodiments assume the function of the trap electrode at the same time, the electrical potential of the trap electrode can thus also be influenced, in particular independently of operation of the corona discharge, which is advantageous for the functionality of the particle sensor.

In preferred embodiments, a resistance value of

Resistance element between about 10 megohms and about 2 gigaohms, preferably between about 200 megohms and about 600 megohms.

In a further embodiment, a first part of the counter electrode is arranged directly on the first surface of the base body, and at least a second part of the counter electrode protrudes from the first surface at least in regions. For example, in some embodiments, the

Counterelectrode at least in a first region or part of

Counter electrode arranged on the first surface of the base body, which allows a simple electrical contacting of the counter electrode, for example, arranged on the first surface of conductor tracks or conductor structures. Furthermore, it can be provided that a second region or part of the counterelectrode, which differs from the first region or part, from the first

Surface of the body protrudes, so from the first surface protrudes. As a result, further degrees of freedom for the generation of charged particles or charged particles are given by defining a space region which can be acted upon by a corona discharge over the first surface by shaping the shape of the projecting counterelectrode. At the same time, a particularly simple mechanical and / or electrical connection results

Counter electrode with arranged on the first surface of the base body components (for example, conductor tracks).

In a further embodiment, at least one sensor electrode is provided for detecting information about an electric charge flow caused by particles from the fluid flow generated by means of the

Particle charger were charged, wherein the at least one sensor electrode is disposed on the first surface. In a particularly preferred embodiment, the

Particle charger or its high voltage electrode and

Counter electrode and the optional sensor electrode arranged along a longitudinal axis of the base body on the first surface thereof,

in particular behind one another or along a flow direction of the

Fluid flow or exhaust gas flow. As a result, the particle charging device, for example by means of the corona discharge, particles or particles of the

Charge exhaust stream, which are then transported by the prevailing gas flow in more downstream areas along which, for example, a portion of the counter electrode may extend, the

Provides functionality of the trap electrode. There can be comparatively easy

(low-mass) charged particles which do not adhere to the particles to be measured, such as ions of the exhaust gas flow, by means of the trap electrode working parts ("trap electrode region") of the counter electrode

be deflected relatively strong, so that they not or only in greatly reduced numbers to the optional, further downstream

Get sensor electrode. As a result, essentially only the relatively heavy charged particles of interest, in particular soot particles, pass further downstream via the trap electrode region

Counter electrode addition, for example, to the sensor electrode, where they can be detected, for example by means of charge influence on the sensor electrode in a conventional manner. In embodiments which have no sensor electrode, the so-called "escaping current" principle can be used to measure a charge current of the charged particles

Particle sensor containing system are isolated to the outside, and it is an electric current measured, which carry the charged particles in the form of their electrical charge from the otherwise electrically isolated and therefore closed system. For example, the considered electric current flows from a needle electrode of the high voltage electrode through the corona discharge into the counter electrode of the high voltage electrode, and the trapping electrode portion of the counter electrode traps the remaining ions. The

Strom, which is generated by the charged particles, the must

Counter electrode is added again so that their electrical potential remains constant. It is called "escaping current" and is a measure of the concentration of charged particles.

In a further embodiment, at least one first protection electrode is provided which surrounds the at least one sensor electrode at least partially, but preferably completely and substantially annularly.

For example, the sensor electrode is arranged completely on the first surface of the base body. In some embodiments, then the first

Protective electrode also be formed substantially flat and preferably surround the entire sensor electrode annular. The first protection electrode, which can also be referred to as a "guard electrode", serves to protect the

Increase the sensitivity of the particle sensor. In particular, the provision of at least the one first guard electrode can result in a signal-to-noise

Ratio (SNR, signal-to-noise ratio) can be reduced in the evaluation of a sensor signal obtainable by means of the sensor electrode.

In a further embodiment it is provided that a region of the counter electrode surrounds the high-voltage electrode at least partially, but preferably completely and substantially annularly. This allows leakage currents, e.g. minimized in the direction of an optional sensor electrode and the signal-to-noise ratio can be further improved.

In a further embodiment it is provided that a second

Protective electrode is provided, the at least one other electrode (For example, the counter electrode or at least one trap electrode region of the counter electrode and / or the possibly existing first guard electrode) of the particle sensor at least partially, but preferably completely and substantially annular, surrounds.

In a further advantageous embodiment, a sensor device comprising a protective tube arrangement of two concentrically arranged tubes and at least one particle sensor according to the invention is proposed, wherein the at least one particle sensor is arranged in the inner tube of the two tubes, that its first surface in the

Aligned substantially parallel to a longitudinal axis of the inner tube. As a result, the particle sensor is advantageously protected from external influences (for example, also from direct flow through exhaust gas), and at the same time it is ensured that a uniform or laminar flow of the exhaust gas flow is applied to the particle sensor, whereby the sensor accuracy is increased.

In particular, in the embodiments, an operation of the particle sensor without the supply of fresh gas or fresh air can be done thereby, whereby a corresponding pump, as required in conventional systems, can be omitted.

Further embodiments are given by a method for producing a particle sensor according to claim 13. The method comprises: providing the base body, arranging the high-voltage electrode on the first surface of the base body, at least partially arranging the counter-electrode on the first surface, in particular so relative to the

High voltage electrode, that it can deflect charged particles of the fluid stream. Particularly preferred may in some embodiments

Siebdruckverfahren, in particular platinum screen printing, be used to the particle charging device or components thereof and the trap electrode area and optionally an optional sensor electrode or equivalent

Apply conductor tracks or conductor structures on the first surface of the body.

Other features, applications and advantages of the invention will become apparent from the following description of embodiments of the invention, which are illustrated in the figures of the drawing. Make up all described or illustrated features alone or in any combination the subject matter of the invention, regardless of their

Summary in the claims or their dependency and regardless of their formulation or representation in the description or in the drawing.

In the drawing shows:

FIG. 1 shows a schematic side view of a first embodiment of the particle sensor according to the invention,

FIG. 2 schematically shows a side view of a second embodiment of the particle sensor according to the invention,

Figures 3 and 4 show schematically the arrangement of a particle sensor in one

Target system,

FIG. 5 schematically shows a plan view of a particle sensor according to a third embodiment,

FIG. 6 schematically shows a plan view of a particle sensor according to a fourth embodiment,

FIG. 7A schematically shows a plan view of a particle sensor according to a fifth embodiment,

FIG. 7B schematically shows a front view in cross section of the particle sensor from FIG. 7A according to line B-B, FIG. 8 schematically shows a plan view of a particle sensor according to a further embodiment, and FIG

FIG. 9 schematically shows a simplified flowchart of a

Embodiment of the method according to the invention. FIG. 1 schematically shows a side view of a first embodiment of the particle sensor 100 according to the invention. The particle sensor 100 has a preferably planar base body 110, which is provided, for example, by a substrate made of an electrically non-conductive material, such as a

Ceramic material can be formed. In the present case, the base body 1 10 a

Thickness d1, which is preferably smaller, in particular substantially smaller (e.g., at least about 80% smaller than a length L extending along the x-axis and smaller than a width extending perpendicular to the plane in FIG.

According to the invention, a particle charging device 120 is arranged in the region of a first surface 11a of the main body 110, which is an outer surface of the main body 110 in FIG. 1. In the present case, the particle charging device 120 is particularly preferably arranged directly on the first surface 110a.

The particle charging device 120 is provided for charging particles (not shown) which may be located in a fluid flow A1 flowing over the first surface 110a of the base body 110. For this purpose, the

Particle charger 120, a high voltage electrode 122, the

Generation of a corona discharge 123 is provided. For this purpose, the

High voltage electrode 122 may be connected, for example, to a high voltage source not shown in Figure 1. Furthermore, the

Particle charging device 120 via a counter electrode 124, the present fully or completely on the first surface 1 10a of the main body

1 10 is arranged, resulting in a simple contact by means of on the first surface 1 10a providable interconnects (not shown in Figure 1) and overall a small-sized configuration results. The dashed ellipse in FIG. 1 indicates a region of increased ion concentration.

According to the invention it is provided that the counter electrode 124 to it

is designed and arranged to deflect charged particles of the fluid flow A1. For this purpose, the counter-electrode 124, in addition to a first region 124a, which acts primarily as an electrical counterelectrode to the high-voltage electrode 122, a second region 124b, which realizes the function of a trap electrode according to the invention and therefore also as a trap electrode region referred to as. The trap electrode region 124b of the counter electrode 124 is provided for deflecting charged particles of the fluid flow A1, which have been generated, for example, by means of the particle charging device 120 farther upstream with respect to the fluid flow A1. Particularly advantageously, particles charged by the trap electrode region 124b,

ions, in particular, are deflected out of the fluid flow A1 so that they do not reach the downstream sensor array 140. In some embodiments, the counterelectrode 124 may be exposed to an electrical potential different from that of the sensor electrode 140

High voltage potential differs, with which the high voltage electrode 122 can be acted upon. In the configuration shown in FIG. 1, the main body 110 extends with its length L between the coordinates x0, x6 of the x-axis horizontal in FIG. The high voltage electrode 122 is arranged approximately in the region of the coordinate x1> x0, and the counter electrode approximately between the

Coordinate values x2, x3, where x2> x1 and x3> x2.

The optional sensor electrode extends approximately between them

Coordinate values x4, x5, with x4> x3, x5> x4. It is for the capture of

Information about an electric charge flow provided by charged particles from the fluid flow A1 is provided. For example, these may be particles which are conveyed by means of the particle charging device

120 or electrically charged by means of the corona discharge 123 generated by them further upstream with respect to the fluid flow A1 (that is, for example, approximately in the region of the coordinate x2). Preferably, only comparatively heavy charged particles pass in the direction

downstream of the sensor electrode 140 because, as described above, comparatively light charged particles such as ions are deflected by the trap electrode region 124b of the counter electrode 124. As a result, the sensor electrode 140 makes it possible to determine a charge by means of a measurement of the charge influence which is caused by charged particles flowing past the sensor electrode 140

Concentration of the charged particles in the fluid flow A1. For example, can the fluid flow A1 is an exhaust gas flow of an internal combustion engine (not shown). For example, the particles may be around

Soot particles act as they arise in the context of combustion of fuel by an internal combustion engine.

In further embodiments, it is conceivable not to provide an optional sensor electrode 140. In these variants of the invention, the so-called "escaping current" principle can be used to measure a charge current of the charged particles For this purpose, the complete system containing the particle sensor 100 can be insulated to the outside, and an electric current is generated

measured, which carry the charged particles in the form of their electrical charge from the otherwise electrically isolated and therefore closed system 100. For example, the electric current under consideration flows from the high voltage electrode 122 through the corona discharge 123 into the

Counter electrode 124 of the high voltage electrode, and the trap electrode

Area 124b captures the remaining ions. The current generated by the charged particles must be added to the counter electrode 124 again so that its electrical potential remains constant. It is called "escaping current" and is a measure of the concentration of charged particles.

In the embodiment depicted in FIG. 1, an electrically conductive element (not shown), for example a metal sheet, may optionally be provided as the counterelectrode for the trap electrode region 124b, which, for example, is arranged above the first surface 110a of the base body 100 according to FIG is. In some embodiments, e.g. a the

Particle sensor 100 surrounding protective tube (not shown in Figure 1) of an electrically conductive material or with an at least partially present electrically conductive surface as a counter electrode for the trap electrode region 124b serve.

FIG. 2 schematically shows a side view of a second embodiment 100a of the particle sensor according to the invention. The particle sensor 100a has a voltage source 130 for supplying, ie electrical energy supply, the particle charging device 120, wherein a first terminal 132a of the

Voltage source 130 electrically conductive with the high voltage electrode 122nd is connected, and wherein the counter electrode 124 is electrically conductive via a resistive element 134 with a second terminal 132 b of

Voltage source 130 is connected. For example, the voltage source 130 may be configured to generate a first voltage U1 ("high voltage" for generating the corona discharge 123), which in some embodiments may be in the range of a few kilovolts (kV), for example.

By the providence of the resistance element 134, in which it is

According to preferred embodiments, it can be a substantially purely resistive resistance element, resulting in advantageous degrees of freedom with respect to an operation of the particle sensor 100a. For example, by selecting the resistance value of the resistive element 134 and the other operating parameters such as the voltage provided to the voltage source 130, the electrical potential of the

Counterelectrode 124 can be influenced. Since, according to the embodiments, this simultaneously assumes the function of a trap electrode, compare the trap electrode region 124b (FIG. 1), the electrical potential of the trap electrode or of the trap electrode region 124b can thus also be influenced. in particular independent of operation of the corona discharge 123, which is advantageous for the functionality of the particle sensor 100a.

In preferred embodiments, a resistance value of

Resistor element 134 between about 10 megohms and about 2 gigaohms, preferably between about 200 megohms and about 600 megohms.

During operation of the particle sensor 100a, an electrical voltage U2, which is dependent inter alia on a corona current in the region of the corona discharge 123 which flows, for example, from the high-voltage electrode 122 to the trap electrode region 124b, drops at the terminals 134a, 134b of the resistance element 134 , Preferably, the second port 132b is the

Voltage source 130 and the second terminal 134b of the resistor element 134 with a reference potential, for example, the ground potential GND, connected. In some embodiments, a required voltage between the high voltage electrode 122 and the trap electrode region 124b may be determined by a suitable choice of the geometry of the particle sensor

Components and the desired corona current can be determined, so for example by the operating point of the corona discharge (typically

Current with current levels in the range of a few microamps (μΑ), at a few kilovolts (kV) voltage, which corresponds to an impedance in the gigaohm range). In some embodiments, it may be provided that the voltage source 130, in addition to the actual corona voltage, also supplies the voltage U2 of the trap electrode region, which may amount to a few 100 V, for example.

Also shown in FIG. 2 is an optional sheet B, which can be used as a counter electrode for the trap electrode region 124b (FIG. 1). As can be seen from FIG. 2, it is arranged, for example, over the first surface 110a of the main body 100. In some embodiments, e.g. a protective tube (not shown in FIG. 2) surrounding the particle sensor 100 assumes the function of the sheet B. For example, in one embodiment, the sheet B may be connected to an electrical reference potential, such as ground potential.

FIG. 3 schematically shows the arrangement of the particle sensor 100 according to FIG. 1 in a target system Z, which in the present case is an exhaust tract of an internal combustion engine, for example of a motor vehicle. A

Exhaust gas flow is referred to herein by the reference numeral A2. Also shown is a protective tube arrangement of two mutually concentrically arranged tubes R1, R2, wherein the particle sensor 100 is arranged in the inner tube R1, that its first surface 1 10a is substantially parallel to a longitudinal axis LA of the inner tube R1. Due to the different lengths and the arrangement of the tubes R1, R2 relative to each other is due to the Venturi effect a suction in which the

Exhaust gas flow A2 causes a fluid flow P1 or A1 out of the inner tube R1 out in Figure 2 in a vertical upward direction. The further arrows P2, P3, P4 indicate the continuation of this caused by the Venturi effect fluid flow through a gap between the two tubes R1, R2 through to the environment of the protective tube assembly towards. Overall, by the arrangement shown in Figure 3 is a comparatively uniform Overflow of the particle sensor 100 and its along the fluid flow P1 aligned first surface 1 causes 10a, which allows efficient detection of particles in the fluid flow A1, P1. In addition, the particulate sensor 100 is protected from direct contact with the main exhaust stream A2. Thus, a sensor device 1000 for determining a particle concentration in the exhaust gas A2 is advantageously indicated by the elements 100, R1, R2.

The reference symbol R2 'indicates an optional electrical connection of the outer tube R2 and / or the inner tube R1 to a reference potential, such as the ground potential, so that the respective tube or both tubes advantageously at the same time as their fluidic guiding function as electrical counter electrode, for example for the trap 1, can be used and, for example, assumes the function of the sheet B described above with reference to FIG. 2.

The block arrow P5 symbolizes in FIG. 3 an optional supply of fresh gas, in particular fresh air supply, which may be desirable in some embodiments, but is not provided in particularly preferred embodiments.

FIG. 4 schematically shows an exhaust pipe R and parts of the sensor device 1000 according to FIG. 2 in the exhaust pipe R. In particular, FIG. 3 again shows the particle sensor 100 according to the invention inside the protective pipe arrangement R1, FIG.

R2 (Fig. 2). The particle sensor 100 is aligned in the protective tube assembly so that its first surface extends along the x-axis, whereas the flow direction of the exhaust gas A2 in the exhaust tube R is aligned parallel to the y-axis.

Hereinafter, with reference to Figures 5, 6, 7A, 7B, 8 further embodiments of the particle sensor according to the invention will be described.

FIG. 5 schematically shows a plan view of a particle sensor 100b according to a third embodiment. The main body 1 10 is formed as a substantially planar ceramic substrate element, and on its first Surface 1 10a are the high voltage electrode 122, a counter electrode 124 and a sensor electrode 140 applied, for example by means of

Screen printing process, in particular platinum screen printing process. The high-voltage electrode 122 has its right end section in FIG

122 'a tip on which the corona discharge 123 can be ignited. The counterelectrode 124 in turn has a first region 124a, which essentially acts as an electrical counter electrode to the

High voltage electrode 122 acts as well as a trap electrode region 124b. The counterelectrode 124 is as schematically shown in FIG. 2 and already described above via a resistance element 134 with the

Reference potential, in this case ground potential GND, connected to which also the second terminal 132b of the voltage source 130 is connected. In particular, the counter electrode 124 has a connection region 1240, which

For example, in the manner of a conductor track can be formed and extend over a comparatively large longitudinal portion of the base body 1 10 in Figure 5 in the horizontal direction to a simple electrical

Contacting of the counter electrode 124 in a left in Figure 5 area, compare the connection point 1241 to allow. By the above-described configuration, the counter electrode 124 becomes an electric

Potential between the ground potential GND and the

High voltage potential from the first terminal 132 a of the voltage source 130 laid. The ions released at the corona tip in region 122 'charge at one

Embodiment, the soot particles located in the exhaust gas electrically. The excess ions are then removed by the electric field between a protective tube wall acted upon, for example, by the ground potential GND (see FIG. 3 or sheet B from FIG. 2) and the trap electrode region 124b of the counter electrode 124. The charged soot particles then generate a charge on the sensor electrode 140, which is amplified and read out. For this purpose, for example, a preamplifier 141 may be provided, whose input 141 a is electrically connected to the sensor electrode 140. This can be done, for example, via a connecting strip 1440, which in turn is essentially designed as a conductor track, and, for example, an electrical connection

Connection point 1441 be realized. An output signal of the preamplifier 141 For example, it may be supplied to an optional signal processing device 142, which may comprise, for example, a digital signal processor (DSP). An electrical connection of the high-voltage electrode 122 can likewise take place via a connection area 1220, which is formed substantially in the manner of a conductor track, and the connection point 1221, which is electrically conductively connected to the first terminal 132a of the voltage source 130. In a preferred embodiment, the terminal areas 1220, 1240, 1240,

1440 substantially along a longitudinal direction of the main body 110, ie in the illustration according to FIG. 5 substantially horizontally, in particular approximately parallel to one another, resulting in a space-saving configuration and efficient contacting of the various electrodes arranged at different longitudinal coordinates of the main body 110 results. In this way, for example, the electrical contact external

Components in a left in Figure 5 area of the particle sensor 100b done. As can be seen from FIG. 5, an electrical contacting of the particle sensor 100b or of the electrical components which is located on the particle sensor 100b or the electrical components

Basic body 1 10 are arranged, by means of only three supply terminals 1221,

1241, 1441 possible.

In a further embodiment, it is conceivable to at least partially expose or to undermine the substantially planar needle electrode arranged in the region 122 ', which can be realized, for example, by the fact that material of the material located directly beneath the region of the tip

Basic body 1 10 is removed. In another embodiment, a structuring of the electrode tip, for example by a

Laser structuring, conceivable and advantageous.

FIG. 6 schematically shows a plan view of a particle sensor 100c according to a fourth embodiment. The main body 1 10 is formed as a substantially planar ceramic substrate element, and on its first surface 1 10a are in turn the high voltage electrode 122, a

Counter electrode 124 and a sensor electrode 140 applied, for example by means of screen printing, in particular platinum screen printing.

In the present case, a region 1240 'of the counter-electrode 124 surrounds the

High voltage electrode 122 annular, whereby leakage currents, in particular to the sensor electrode 140 are minimized, whereby the signal to noise ratio can be increased in the measurement. Such an annular arrangement of at least a portion 1240 'of the counter electrode 124 around the

High-voltage electrode 122 is according to further embodiments also in at least one of the above with reference to Figure 1, FIG

2, Figure 5 described configurations 100, 100a, 100b possible.

In a further advantageous embodiment, furthermore, a first

Protective electrode 145 is provided which surrounds the sensor electrode 140 at least partially, but preferably completely and substantially annularly. This first protection electrode 145 may also be referred to as a "guard ring electrode" and also serves to improve the SNR of the

Particle sensors 100c. Optionally, it is also possible to provide a second protection electrode 145 ', which in FIG.

Is indicated only schematically and at least one other electrode of the particle sensor 100c, in this case the counter electrode 124, at least partially, but preferably completely and substantially annular, surrounds.

As a result, unwanted leakage currents can be better suppressed and the SNR can be further increased.

Fig. 7A schematically shows a plan view of a particle sensor 10Od according to a fifth embodiment, and Fig. 7B shows a cross section along line B-B of Fig. 7A. The elements 1 10,122,124,140 substantially correspond to those described above with reference to FIG

Embodiment. In contrast to the configuration according to FIG. 6, however, provision is made in the configuration according to FIG. 7A for a first part 1242a of the counterelectrode 124, in particular directly, to be arranged on the first surface 110a, at least a second part 1242b of the counterelectrode 124 at least in regions protrudes from the first surface 1 10a. This advantageously allows a tip of the high voltage electrode 122 to be in the For example, the needle electrode 122 "may be arranged substantially perpendicular to the first surface 110a or integrated into it. As a result, a corona discharge 123, cf. FIG. 7B, can be ignited against the region 1242b of the counterelectrode.

As already described with reference to FIG. 1, the counterelectrode 124, compare FIG. 7A, can be connected to the ground potential via a resistance element 134 (FIG. 2), so that the trap electrode region of FIG

Counter-electrode 124, for example with a particle sensor 100th

surrounding protective tube wall (not shown) form an electric field and thus can suck excess ions from the fluid stream. As already described above, the main body 1 10 of the

Particle sensor according to the invention advantageously made of a ceramic

Carrier substrate exist. The carrier substrate may comprise, for example, zirconium or aluminum oxide and serves as a carrier for the various

Components of the particle sensor, which are preferably all arranged together on the first surface 1 10a, resulting in a particularly efficient and cost-effective production. For example, the conductive patterns 122, 124, 140, 1220, 1240, 1440 (FIG. 7A) may be efficiently deposited on the first surface 11a by known manufacturing technologies, for example, using screen printing techniques.

in particular platinum screen printing process. This can be special

temperature-stable and reliable structures are generated.

In a particularly preferred embodiment, the

High voltage electrode 122 or a portion of the high voltage electrode 122 and the needle electrode 122 "may be formed, for example, of platinum or tungsten or a material containing at least one of these metals and, for example by means of a screen-printed platinum paste by sintering on the substrate or the base body 1 10a mechanically fixed and at the same time electrically conductive with this or arranged thereon

Track structure 1220 are connected. Alternatively, other connection methods are also conceivable for the components 122 and their needle electrode 122 ", the same applies to the other electrodes or printed conductors, Figure 8 schematically shows a plan view of a particle sensor according to a further embodiment 100e, in particular on one of its first surface 110a (FIG. 1) opposite second surface 110b, which is, for example, a "bottom" of the particle sensor 100e. On this second surface 1 10 b, an electric heater 160 is provided, which preferably meander-shaped heating conductors 162 and

corresponding electrical connections 164 has. The production of the structures 162, 164 can, in turn, advantageously be effected by means of screen printing, in particular by means of platinum screen printing. The electric heater 160 may be used, for example, to increase the temperature of the particulate sensor 100e, in particular particulate deposits, in particular

Soot deposits, reduce or eliminate. Otherwise, such deposits could lead to a reduction in the creepage distances or the

electrical resistance between the electrodes on the per se electrically non-conductive substrate 1 10, in particular its first surface 1 10a, and finally lead to an electrical short circuit. At further

Embodiments, the heater 160 may also be configured to increase a temperature of the particle sensor at least temporarily over a predetermined target temperature, in particular in a range between about 650 ° C to about 700 ° C, to selectively burn off deposits, especially soot deposits.

FIG. 9 shows schematically a simplified flowchart of a

Embodiment of the method according to the invention. The method comprises: providing 200 of the main body 110 (FIG. 1), arranging 202 (FIG. 9) the high voltage electrode 122 on the first surface 110a of the main body

1 10, at least partially disposing 204 (FIG. 9) of the counterelectrode 124 on the first surface 110a, in particular so relative to the high voltage electrode 122 that it can deflect charged particles of the fluid flow A1 (FIG. 1), eg, downstream of the high voltage electrode 122 with respect to the fluid flow A1. The embodiments 100, 100a, 100b, 100c, 100d, 100e, 1000 described above by way of example or in other advantageous embodiments can also be described in other embodiments than those described above

Combinations are used together.

Particularly advantageously, the particle sensor 100, 100a, 100b, 100c, 100d, 100e according to the invention preferably has a planar ceramic substrate, which forms the base body 110, and on the surface 110a of which are various components of the particle sensor, such as electrodes and

corresponding electrical leads or conductors arranged, which allows a particularly simple production. The particle sensor according to the invention can be arranged particularly simply in a protective tube or protective tube arrangement R1, R2, cf. FIG. 3, and thus exposed to a uniform fluid flow A1, P1, which enables a precise measurement of the concentration of particles, in particular of soot particles. As already described above, variants with at least one

Sensor electrode 140 or even a plurality of sensor electrodes (not shown) possible, and variants are also possible without sensor electrode, in which preferably the "escaping currenf measuring principle is used to determine a concentration of charged particles. The preferred planar

Design of the particle sensor further allows cost-effective production and storage and a small-sized configuration for a corresponding target system Z (Fig. 3). In some embodiments, it is particularly advantageous to use screen-printing electrodes, in particular platinum screen-printed electrodes, in combination with planar and / or protruding elements 122 ", 1242b from the first surface 110a

Use of the combined trap and counter electrode is also particularly advantageous for operation and saves an electrical connection. The particle sensor according to the invention can be particularly preferred as

Soot particle sensor are used in the automotive field, in particular as OBD (on board diagnosis) - sensor for monitoring a particulate filter in motor vehicles such as passenger cars (cars), commercial vehicles (commercial vehicles). The particle sensor according to the invention can also be used in general for measuring the concentration of particles in a fluid flow, in particular for measuring a concentration of dust particles or Particulate matter, and can therefore be used advantageously especially in environmental metrology.

The particle sensor according to the invention advantageously allows both the

Determination of a mass concentration, for example given in milligrams per cubic meter (mg / m ³ ), as well as the determination of a number concentration, for example measured in particles per cubic meter. Particularly advantageously, the particle sensor can be used for monitoring particle filters in internal combustion engines, both in self-igniting internal combustion engines as well as in spark-ignition internal combustion engines. Furthermore, the

Particle sensor according to the invention, the determination of particle concentrations in environmental metrology and other areas, in particular for the determination of indoor air quality, emissions from incinerators (private, industrial), etc ..

The measuring principle used according to the invention is based on a charging of particles, in particular soot particles, by means of a corona discharge in the fluid flow A1 (FIG. 1) and a subsequent measurement of the charge of the particles or of the soot particles or the measurement of a corresponding current resulting therefrom , The measurement can, for example, by means of

Charge influence on a sensor electrode 140 (FIG. 1) or according to the escaping currenf principle. The measuring principle used according to the invention has a very high sensitivity, as a result of which even the smallest concentrations of particles can be measured. Furthermore, the measuring principle used according to the invention advantageously allows comparatively high update rates ("update").

Rates), ie comparatively many measurements per second. This advantageously allows a correlation of the measurement signal obtained in this case, for example, with other operating variables, such as operating variables of a

Internal combustion engine, in the exhaust stream of the particle sensor is arranged, which advantageously improves the data evaluation and thus another

Increasing the sensor accuracy has the consequence.

Claims

claims

1 . Particle sensor (100; 100a; 100b; 100c; 10Od; 10Oe) having a base body (110), a particle charging device (120) for charging particles in a first surface (110a) of the base body (110).

flowing fluid stream (A1), wherein the particle charging device (120) arranged in the region of the first surface (1 10a)

A high voltage electrode (122) for generating a corona discharge (123) and a counter electrode (124), wherein the counter electrode (124) is formed and arranged, charged particles of the

Distracting fluid flow (A1).

2. Particle sensor (100, 100a, 100b, 100c, 10Od, 10Oe) according to claim 1, wherein the high voltage electrode (122) at least partially, in particular directly, on the first surface (1 10a) of the base body (1 10) is arranged and the counter-electrode (124) is arranged at least partially, in particular directly, on the first surface (110a) of the base body (110).

Particle sensor (100; 100a; 100b; 100c; 100d; 100e) according to at least one of the preceding claims, wherein a voltage source (130) for

Supply of the particle charging device (120) is provided, wherein a first terminal (132 a) of the voltage source (130) with the

High voltage electrode (122) is connected, and wherein the

Counter electrode (124) via a resistor element (134) to a second terminal (132b) of the voltage source (130) is connected.

The particle sensor (100; 100a; 100b; 100c; 10Od; 10Oe) of claim 3, wherein a resistance of the resistive element (134) is between about 10 megohms and about 2 gigaohms, preferably between about 200 megaohms and about 600 megohms.

Particle sensor (100; 100a; 100b; 100c; 100d; 100e) according to at least one of the preceding claims, wherein a first part (1242a) of the

Counter electrode (124) directly on the first surface (1 10a) is arranged, and wherein at least a second part (1242b) of the counter electrode (124) at least partially protrudes from the first surface (1 10a).

Particle sensor (100; 100a; 100b; 100c; 100d; 100e) according to at least one of the preceding claims, wherein at least one sensor electrode (140) is provided for detecting information about an electric charge flow which is caused by particles from the fluid flow (A1). caused by the particle charging device (120), wherein the at least one sensor electrode (140) on the first surface (1 10a) is arranged

Particle sensor (100; 100a; 100b; 100c; 100d; 100e) according to at least one of the preceding claims, wherein the high-voltage electrode (122) and the counter-electrode (124), and in particular also one or more optional sensor electrodes (140), substantially behind one another along a longitudinal axis (L) of the main body (1 10) or a

Flow direction of the fluid flow (A1) are arranged.

A particle sensor (100; 100a; 100b; 100c; 100d; 100e) according to at least one of the preceding claims, wherein the first surface (110a) is an outer surface of the base body (110). A particle sensor (100, 100a, 100b, 100c, 100d, 100e) according to at least one of claims 7 to 8, wherein a first guard electrode (145) is provided, at least partially, but preferably completely, and the at least one sensor electrode (140) essentially annular, surrounds. 10. Particle sensor (100, 100a, 100b, 100c, 100d, 100e) according to one of

preceding claims, wherein a portion (1240 ') of the counter electrode (124) surrounds the high voltage electrode (122) at least partially, but preferably completely and substantially annularly. 1 1. Particle sensor (100, 100a, 100b, 100c, 10Od, 10Oe) according to one of

preceding claims, wherein a second guard electrode (145 ') is provided which at least partially, but preferably completely and at least one other electrode (122, 124, 140, 145) of the particulate sensor (100; 100a; 100b; 100c; 100d; 100e) essentially annular, surrounds.

12. Sensor device (1000) comprising a protective tube arrangement of two mutually concentrically arranged tubes (R1, R2) and at least a particle sensor (100; 100a; 100b; 100c; 100d; 100e) according to at least one of the preceding claims, wherein the at least one

100e; 100b; 100c; 100d; 100e) is arranged in the inner tube (R1) of the two tubes (R1, R2) such that its first surface (110a) is substantially parallel to a longitudinal axis (LA). of the inner tube (R1) is aligned.

13. A method of manufacturing a particle sensor (100; 100a; 100b; 100c;

100d; 100e) having a base body (1 10), a particle charging device (120) for charging particles in a fluid flow (A1) flowing over a first surface (110a) of the base body (110), the particle charging device (120) comprising a high-voltage electrode ( 122) for generating a corona discharge (123) and a counterelectrode (124), the method comprising the following steps: providing (200) the base body (110), arranging (202) the high voltage electrode (122) on the first one Surface (1 10a) of the base body (1 10), at least partially arranging (204) of the counter electrode (124) on the first

Surface (1 10a), in particular so relative to the high voltage electrode (122) that it can deflect charged particles of the fluid stream (A1).