EP3631413A1

EP3631413A1 - Particle sensor and method for producing same

Info

Publication number: EP3631413A1
Application number: EP18723511.4A
Authority: EP
Inventors: Radoslav Rusanov
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-05-24
Filing date: 2018-05-09
Publication date: 2020-04-08
Also published as: KR20200011423A; WO2018215214A1; CN110678732A; DE102017208849A1

Abstract

The invention relates to a particle sensor (100; 100a; 100b; 100c; 100d) having 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), and a trap electrode (130) for deflecting charged particles of the fluid flow (A1), wherein the particle charging device (120) and the trap electrode (130) are arranged on the first surface (110a) of the main body (110).

Description

Description title

Particle sensor and manufacturing method for this state of the art

The invention relates to a particle sensor and 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 according to the invention has a base body, a

A particle charging device for charging particles in a fluid stream flowing over a first surface of the body, and a trap electrode for deflecting charged particles of the fluid flow. Advantageous are the

Particle charger and the trap electrode disposed on the first surface of the base body, resulting in a particularly simple construction and cost-effective production results.

For example, the fluid stream may be an exhaust gas stream of an internal combustion engine of a motor vehicle. For example, it may be in the particles to act as soot particles as they arise in the context of combustion of fuel by an internal combustion engine.

In a preferred embodiment, the base body

Substrate element on or is formed from a substrate element. Particularly preferably, the base body is made of a substantially planar

Ceramic substrate formed. The main body can, for example, a in

Have substantially cuboid basic shape with a width and a length, wherein a height dimension with respect to the width and the length is relatively small. More preferably, the first surface, on which according to the invention the particle charging device and the trap electrode are arranged, an outer surface of the base body.

In a further advantageous embodiment, the

Particle charger on a high voltage electrode for generating a corona discharge. The corona discharge allows for charging of particles or generally particles, e.g. also of gases, from the fluid flow or exhaust gas flow in a space around the high-voltage electrode. Thus, on the one hand, particles are charged directly as they flow through a space located in the region of the first surface, in which the corona discharge takes place. On the other hand, particles on charged particles of Gasbzw. Charged exhaust gas stream, the gas or exhaust gas stream was charged directly when flowing through the room in the region of the high voltage electrode. This overall improves the efficiency of charging. In a preferred embodiment, the high voltage electrode has at least one needle-shaped electrode or tip.

In a further embodiment, the particle charging device has a counter electrode to the high voltage electrode. Under one

In the present case, the counterelectrode is understood to mean an electrode which is different from the high-voltage electrode and which has an orifice with respect to the

High voltage electrode of different electrical potential

can be acted upon. For example, the counter electrode to the

High voltage electrode to be placed on a reference potential such as a ground potential or be firmly connected to a reference potential having circuit node. At further According to embodiments, the high-voltage electrode may be subjected to a positive or negative electrical potential with respect to the counterelectrode.

In a further embodiment, the counterelectrode is also preferably arranged on the first surface, which results in a particularly simple construction and efficient production of the particle sensor.

Particularly preferably, the counterelectrode is completely on the first

Surface arranged.

In a further preferred embodiment, the counter electrode to the high voltage electrode may simultaneously form a counter electrode to the trap electrode.

In one embodiment, the trap electrode can be subjected to the same electrical potential that is applied to the high-voltage electrode. This can be done, for example, in that both the high-voltage electrode and the trap electrode are connected to a common high-voltage supply.

In a further embodiment, the counterelectrode is arranged on the first surface of the base body at least in a first region of the counterelectrode, which enables a simple electrical contacting of the counterelectrode by conductor tracks or conductor structures arranged on the first surface. Furthermore, it can be provided that a second region of the counterelectrode, which is different from the first region, protrudes from the first surface of the base body, that is to say protrudes from the first surface. 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 preferred embodiment, the counter-electrode has a substantially curved basic shape, for example corresponding to a sector of a lateral surface of a circular cylinder. Particularly preferably, the counter electrode is associated with its concave outer side of the first surface of the base body. In a preferred embodiment, the counter electrode or at least one of the first surface of the

Base body protruding portion of the counter electrode may be formed by a metal sheet.

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

Particle charger were charged, wherein the at least one sensor electrode is also disposed on the first surface.

In a particularly preferred embodiment, the

Particle charging device, the trap electrode, and the optional sensor electrode arranged along a longitudinal axis of the base body on the first surface thereof, in particular along a flow direction of the fluid flow or exhaust gas flow. Thereby, the particle charging device, for example by means of a corona discharge charge particles or particles of the exhaust gas stream, which are then transported by the prevailing gas flow in the region of the trap electrode. There you can

comparatively light (low-mass) charged particles, which do not adhere to the particles to be measured, such as ions of the exhaust gas flow are deflected relatively strong by means of the trap electrode, so that they not or only in greatly reduced numbers to the optional, further downstream sensor electrode reach. As a result, essentially only the relatively heavy charged particles of interest,

in particular soot particles, further downstream beyond the trap electrode, for example to the sensor electrode, where, for example, by means of

Charge influence on the sensor electrode can be detected in a conventional manner.

In one embodiment, it is also conceivable to apply an electrical potential to the trap electrode which is controllable or at least is different from the electrical potential of the high voltage electrode, whereby a degree of freedom for adjusting the trapping effect of the trap electrode is given with respect to the charged particles or particles flowing past it.

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 (in particular, this is the counter electrode of the high voltage electrode and an optional counter electrode for the trap electrode "virtual", such as a virtual ground electrode), and it is an electric current is measured, which the charged particles in shape For example, the electric current under consideration flows from a needle electrode of the high voltage electrode through the corona discharge into the counterelectrode of the high voltage electrode, and the trap electrode traps the remaining ions. which is generated by the charged particles, the counter electrode must be added again so that its electrical potential remains constant, it is called "escaping current" and is a measure of the concentration of charged particles.

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 against external influences (for example, also from direct flow through exhaust gas), and at the same time it is ensured that a uniform 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 10. The method comprises providing the main body, for example in the form of an im

substantially planar (ie having a planar first outer surface) ceramic substrate, and disposing the particle charging means and the trap electrode on the first surface of the base body. In some embodiments, screen printing methods, in particular platinum screen printing, can be used with particular preference in order to achieve the

Particle charger or components thereof and the trap electrode and optionally an optional sensor electrode or corresponding conductor tracks or conductor structures to be applied to the first surface of the base 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. All described or illustrated features alone or in any combination form 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,

FIG. 3 schematically shows the arrangement of the particle sensor according to FIG. 1 in a target system, FIG.

FIG. 4A schematically shows a plan view of a particle sensor according to a second embodiment, FIG. 4B schematically shows a cross section with a view in the longitudinal direction of the

Particle sensor according to FIG. 4A,

FIG. 4C schematically shows a side view of the particle sensor according to FIG.

4A,

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

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

FIG. 6B schematically shows a cross section with a view in the longitudinal direction of the

Particle sensor according to FIG. 6A,

FIG. 7 schematically shows a plan view of a particle sensor according to FIG

a further embodiment, and

FIG. 8 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 110 has a thickness d1 which is preferably smaller, in particular substantially smaller (eg smaller by at least about 80% than a length L extending along the x-axis and smaller than a perpendicular to the plane of the drawing in FIG ready.

According to the invention, a particle charging device 120 and a trap electrode 130 are arranged on a first surface 110a of the base body 110, which is an outer surface of the base body 110 in FIG. 1. 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, for example, a high voltage electrode 122, which is provided to generate a corona discharge 123. For this purpose, the high-voltage electrode 122, for example, to a not shown

High voltage source to be connected. Optionally, the

Particle charging device 120 also have a counter electrode of or for the high-voltage electrode 122, which in the present case is denoted by the reference numeral 124 and advantageously also, in particular completely or

over the entire surface, on the first surface 1 10a of the base body 1 10 is arranged.

The trap electrode 130 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.

For example, the trap electrode 130 may be electrically powered with the same

Potential to be applied, such as the high voltage electrode 122. In other embodiments, the trap electrode may also be applied to a different electrical potential than that of the high voltage electrode 122. Particularly advantageously, particles charged by the trap electrode 130, in particular ions, can be deflected or "trapped" out of the fluid flow A1 so that they do not reach the downstream sensor electrode 140.

The sensor electrode 140 is provided for detecting information about an electric charge current caused by charged particles from the fluid flow A1. By way of example, these may be particles which, by means of the particle charging device 120 or by means of the corona discharge 123 generated by them, continue further upstream relative to the corona discharge 123

Fluid flow A1 have been electrically charged. Preferably, only comparatively heavy charged particles pass downstream to the sensor electrode 140 because, as described above, relatively light charged particles such as ions are deflected by the trap electrode 130. Thereby, the sensor electrode 140 allows by means of a measurement of the charge influence, which at through the Sensor electrode 140 is caused by passing charged particles, the determination of a concentration of the charged particles in the fluid flow A1. For example, the fluid flow A1 may be an exhaust gas flow of an internal combustion engine (not shown). For example, the particles may be soot particles, such as those produced as part 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 isolated to the outside (in particular, the

Counter electrode of the high voltage electrode and an optional counter electrode for the trap electrode "virtual"), and it is an electrical current measured which carried out the charged particles in the form of their electrical charge from the otherwise electrically isolated and therefore closed system 100. For example, flows observed electric current from the high voltage electrode 122 through the corona discharge 123 into the counterelectrode 124 of the high voltage electrode, and the trap electrode 130 or its counter electrode not shown catch the remaining ions, the current generated by the charged particles must can be added back to the counterelectrode 124 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, the counter-electrode for the trap electrode 130 may be an electrically conductive element (not shown),

For example, a metal sheet may be provided, which is arranged above the first surface 110a of the main body 100. In some embodiments, e.g. a protective tube surrounding the particle sensor 100 (not shown in FIG. 1) made of an electrically conductive material or with an electrically conductive surface present at least in sections

Counter electrode for the trap electrode 130 serve.

FIG. 2 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 gas tract of a Internal combustion engine, for example, a motor vehicle is. 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 2 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 conductive function as electrical counter electrode, for example for the trap -Electrode 130 (and / or for the high voltage electrode 122), see Figure 1, are usable.

The block arrow P5 symbolizes in FIG. 2 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. 3 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 Particulate sensor 100 according to the invention within the protective tube arrangement R1, 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.

A further embodiment 100a of the particle sensor according to the invention is described below with reference to FIGS. 4A, 4B, 4C, wherein FIG. 4A schematically shows a plan view, FIG. 4B schematically shows a

Cross-section with a view in the longitudinal direction (along the axis x, compare Figure 4A) and Figure 4C shows schematically a side view of the particle sensor 100a of this further embodiment.

As can be seen in FIGS. 4A, 4B and 4C, the particle sensor 100a again has a main body 11, for example comprising a ceramic substrate, and a high-voltage electrode 122 which is connected via a

High voltage supply line 121 is supplied with a corresponding electrical potential. In the present case, the high-voltage electrode 122 has a needle electrode which is not separately designated, in order to ignite a corona discharge in cooperation with the counter-electrode 124a (cf. reference symbol 123 from FIG. 1). In contrast to the embodiment according to FIG. 1, in the embodiment according to FIGS. 4A, 4B, 4C, the counterelectrode 124a is not arranged on the entire surface of the surface 11a of the base body 110. Rather, in the present case, the counterelectrode 124a in a first region 1241, compare FIG. 4B, is mechanically and electrically conductively connected to a supply line 1241 ', which connects the counterelectrode 124a to an electric field

Reference potential, in this case, for example, the ground potential, connects.

In contrast, a second area 1242, cf. FIG. 4B, projects

Counter electrode 124a from the first surface 1 10a from, for example, such that it is arranged vertically above the needle electrode 122 in Figure 4B. As a result, as described above several times, a corona discharge (not shown in FIG. 4B) can form between the elements 122, 124a, in particular in the second region 1242, which serves to charge particles or particles of a fluid stream. Furthermore, the particle sensor 100a has a trap electrode 130 which, as shown in FIG. 4A, is arranged along the longitudinal direction x further downstream with respect to the high-voltage electrode 122. In the present case, the trap electrode 130 is electrically conductively connected by means of the connecting line 131 to the high-voltage electrode 122, thus to the common

High voltage power supply connected via the

High voltage supply line 121 is connected.

The counterelectrode 124a is in the present case designed so that it does not only extend over the high-voltage electrode 122 along the longitudinal direction x, compare region 124 'from FIG. 4A, but via its tongue-like form

Extension, compare area 124 ", also extends beyond the trap electrode 130. This can also be seen from the side view of Figure 4C .Thus, the counterelectrode 124a also acts as a counterelectrode for the trap electrode 130, whereby charged particles, which are Moving past the particle sensor 100a along the flow or longitudinal direction x on the first surface 110a, deflecting in the vertical direction, for example towards the trap electrode 130, in FIG. 4B and 4C, in the case of comparatively low mass Particles such as charged gas particles or ions are, they are usually deflected down to the trap electrode 130 back and thus not further downstream to the presently provided also sensor electrode 140. In this way, therefore, only relatively high-mass charged particles such as

For example, by means of the particle charging device 120 charged particles, such as soot particles of an exhaust stream, in the field of

Sensor electrode 140 and can there by means of charge influence on the

Sensor electrode 140 are detected in a conventional manner. An electrical supply line for the sensor electrode 140 is present with the

Reference numeral 141 (Fig. 4A) designates and leads, as well as the other leads 121, 1241 'in a left in Figure 4A arranged first axial end portion 1 10' of the particle sensor 100a.

As can also be seen from FIG. 4A, the components 122, 130, 140 are arranged along the longitudinal direction x, which corresponds to a flow direction of the fluid flow A1 (FIG. 1) flowing over the first surface 110a. In the present case, the sensor electrode 140 is located, for example, in the region of the first axial end portion 1 10 'opposite the second axial end portion 1 10 "of the particle sensor 100a.

In a preferred embodiment, a space b2 of the sensor electrode 140 measured vertically in FIG. 4A is not substantially smaller than the overall width b1 of the base body 110, as a result of which a particularly high sensitivity and thus also measurement accuracy of the particle sensor 100A are achieved. In particularly preferred embodiments, a quotient Q of the two widths, Q = b2 / b1, has values in the range of about 60% to about 100%, in particular values in the range of about 75% to about 98%.

Particularly advantageously, the configuration 100a according to FIGS. 4A, 4B, 4C can be used to provide a planar, ceramic-based particle sensor, in particular for soot particles. The particle sensor 100a includes a high voltage needle electrode 122 and a ground electrode 124a as

Counterelectrode, between which by means of a high voltage, a corona discharge is ignited, whereby a on the first surface 1 10a and in particular between the electrodes 122 and 124a into flowing fluid flow or air / particle flow is charged or ionized. Trap electrode 130 then traps ions and other lighter charged particles from the fluid stream, particularly those charged particles that do not adhere to particles such as soot particles contained in the fluid stream. A charge measurement for the soot particles takes place in this embodiment by means of charge influence on the sensor electrode 140.

As already described above, the main body 1 10 of the

Particle sensors 100a advantageously consist of a ceramic carrier substrate. The carrier substrate may comprise, for example, zirconium or aluminum oxide and serves as a carrier for the various components of the

Particle sensors 100a, which are advantageously all arranged together on the first surface 1 10a, resulting in a particularly efficient and

inexpensive production results. For example, the conductor tracks or conductor structures 121, 131, 141, 1241 'on the first surface 110a can be applied efficiently by means of known production technologies, for example using screen printing methods, in particular platinum screen printing methods. This can be particularly temperature-stable and Reliable structures are generated. The electrodes 122, 130, 140 as well as a counterelectrode 124 (see FIG. 1) arranged on the first surface 110a can likewise be advantageously produced by using the abovementioned screen printing methods, in particular platinum screen printing methods.

In a particularly preferred embodiment, the needle electrode of the high voltage electrode 122, which itself is formed, for example, of platinum or tungsten or a material containing at least one of these metals, for example by means of a screen-printed platinum paste by sintering on the substrate or the base body 1 10a mechanically attached and simultaneously electrically conductively connected to this.

Alternatively, other connection methods for the components 122 and their needle electrode are conceivable. The same applies to the other electrodes or conductor tracks.

In a preferred embodiment of the invention

Manufacturing process is provided in a first step 200, compare Figure 8, the main body 1 10 (Fig. 1), for example in the form of a

ceramic carrier substrate. In a second step 210, cf. FIG. 8, the particle charging device 120 and the trap electrode 130 are arranged on the first surface 110a of the base body 110. This can be done, for example, by means of one of the screen printing methods mentioned above, in particular by means of platinum screen printing. In the same working step, the plurality of components 120, 130 or their electrodes 122, 130 arranged on the first surface 110a may be particularly preferably

if appropriate, corresponding supply lines 121, 131, 1241 'are applied to the first surface 110a in the same working step, which enables a particularly efficient and cost-effective production of the particle sensor.

If the optional sensor electrode 140 is likewise provided, the sensor electrode 140 and its supply line 141 can also be applied to the first surface 110a in the aforementioned operation 210. If a counterelectrode 124 (FIG. 1) is also to be applied to the first surface 110a, in particular over the entire surface, this can also be done in step 210 according to FIG. A counter-electrode 124a projecting at least partially from the first surface 110a, cf. FIG. 4B, can also be applied to the first surface 110a in step 210 or attached to the first surface 110a. In a preferred embodiment, the counterelectrode 124a may, for example, be made of a metal sheet or another material having a planar design, an electrically conductive surface or an electrically conductive surface. Particularly preferably, the counterelectrode 124a can be mechanically fastened to and electrically conductively connected to a predefinable length region of the ground supply line 1141 ', for example by means of a platinum paste and a

subsequent sintering process. In this way, by appropriate shaping of the counter electrode 124a, the one shown in Figure 4A, 4B, 4C

Configuration are obtained, in which the counter electrode 124a at least partially protrudes from the first surface 1 10a and the

High voltage electrode 122 is opposite. The optional tongue-like extension of the counter electrode 124a in the region 124 ", compare Figure 4A, can be used to advantage for forming a counter electrode for the trap electrode 130. As a result, an electric field can be provided between the electrodes 124, 130, the ions from In contrast, heavier charged particles, such as soot particles, are too sluggish due to their mass and fly further in the fluid flow towards the fluid flow above the surface 110a of the particle sensor 100

Sensor electrode 140, where its charge can be measured by charge influence and used as a measure of the particle concentration, in particular soot particle concentration.

Alternatively to the tongue-like extension in the area 124 "of the

Counter electrode 124 may also be a protective tube surrounding the particle sensor 100a, for example, the inner tube R1 of Figure 2, electrically conductive and be applied with a reference potential, so that this tube R1 forms a counter electrode for the trap electrode 130 and / or the high voltage electrode 122 , In a further advantageous embodiment, the configuration of the particle sensor 100a depicted in FIGS. 4A, B, C can be modified such that the sensor electrode 140 and its feed line 141 are omitted. In this variant, a measurement of a particle concentration or

For this purpose, as already mentioned above, the entire arrangement 100a must be electrically insulated in order to be able to measure the "escaping current" which as it were represents a fault current.

FIG. 5 schematically shows a top view of a particle sensor 100b according to a further embodiment, in particular on a second surface 110b, which is opposite to its first surface 110a (FIG. 1) and is, for example, an "underside" of the particle sensor 100b second surface 1 10 b is an electric heater 160 is provided, which preferably meander-shaped Heizleiterbahnen 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 100b, particularly to reduce or eliminate particulate deposits, particularly soot deposits. 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 may also be configured to increase a temperature of the particle sensor 100, 100a, 100b at least temporarily over a predefinable setpoint temperature, in particular in a range between about 650 ° C to about 700 ° C, to deposits, in particular

Soot deposits, deliberately burn off.

Hereinafter, with reference to FIGS. 6A, 6B, another

Embodiment 100c of the particle sensor according to the invention described, wherein Figure 6A schematically shows a plan view and Figure 6B schematically shows a cross section with a view in the longitudinal direction (along the axis x, see Figure 6A). The particle sensor 100c has no sensor electrode (reference numeral 140, see Figure 4A), and a measurement of a concentration of charged particles such as soot particles is carried out here using the escaping currenf principle already described above. The complete system 100c is isolated to the outside, whereby the counter electrode or ground electrode 124b becomes a virtual ground electrode, and the current which the soot particles in the form of their electric current is measured is measured

Remove the charge from the otherwise closed system 100c. For example, the current flows from the needle of the high voltage electrode 122 through the area of the corona discharge into the ground electrode 124b, and the trap electrode 130 traps the remaining ions. The current generated by the charged particles, especially charged soot particles, must be added back to the ground electrode 124b in order to maintain their electrical potential constant. This current is also called "escaping current" and is a measure of the concentration of charged particles.

In contrast to the embodiment according to FIG. 4B, it can be seen from FIG. 6B that the particle sensor 100c has a counter-electrode or

Ground electrode 124b which is mechanically connected in both edge regions 1241 a, 1241 b with the surface 1 10a of the base body 1 10. An electrically conductive connection is provided at least between the region 1241 b and the ground line 1241. A central region 1242 of the ground electrode 124b protrudes from the surface 110a of FIG

Body 1 10, thereby defining a space between the inside of the area 1242 and the high voltage electrode 122, which may comprise the corona discharge, and in which the above-mentioned

Charging of particles or particles, in particular soot particles, can take place.

FIG. 7 shows a plan view of a further embodiment 100d of a particle sensor according to the invention. As in the case of the embodiment according to FIG. 6A, the ground electrode 124c is present on both sides (with reference to FIGS

High voltage electrode 122) on the first surface 1 10a of the base body 1 10 and connected thereto. On a first side, the mechanical and electrically conductive connection is made with the earth lead 1241, and on a second side, in FIG. 7 above the high-voltage electrode 122, at least one mechanical and possibly also electrically conductive connection of the relevant region of the ground electrode 124c to a conductor section arranged on the surface 110a takes place.

In the embodiments 100, 100a, 100b, 100c, 100d described above, the leads or printed conductors and electrodes can preferably be produced by screen printing, in particular by means of platinum screen printing, on the base body 110 or its first surface 110a.

In contrast to the configuration according to Figure 6A, 6B is in the

Particle sensor 100d according to Figure 7, a tongue-shaped axial end portion 124 "provided, which projects beyond the trap electrode 130, whereas the

Mounting regions of the ground electrode 124b do not extend in the axial direction x as far as or along the trap electrode 130. The axial

End region 124 "thus projects freely beyond the trap electrode 130. This provides improved electrical insulation between the electrodes 124c, 130.

The embodiments described above by way of example or their

In further advantageous embodiments, features can also be used in combinations other than those described above.

Particularly advantageously, the particle sensor 100, 100a, 100b, 100c, 100d according to the invention preferably has a planar ceramic substrate which supports the

Base body 1 10 forms, and on the surface 1 10a 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 easily in a protective tube or protective tube arrangement R1, R2, cf. FIG. 2, 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 (FIG. 4A) or even a plurality of sensor electrodes (not shown) are possible, and variants without a sensor electrode (FIGS. 6A, 7) are also possible, in which the "escaping currenf measuring principle" is preferred Determining a concentration of charged particles is used. The planar structure of the particle sensor further allows cost-effective production and storage and a small-sized configuration for a corresponding target system Z (FIG. 2). Particularly advantageous in some embodiments is the use of screen-printed electrodes, in particular platinum screen-printed electrodes, in combination with planar and / or protruding from the first surface 1 10a elements such as the ground electrodes 124, 124a, 124b, 124c.

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, which advantageously permits correlation of the measurement signal obtained here with other operating variables, such as operating variables of one

Internal combustion engine, in the exhaust stream of the particle sensor is arranged, which advantageously has an improvement of the data evaluation and thus a further increase in the sensor accuracy.

Claims

claims

1 . Particle sensor (100; 100a; 100b; 100c; 10Od) having a base body (110), a particle charging device (120) for charging particles in a fluid flow (A1) flowing over a first surface (110a) of the base body (110). , and a trap electrode (130) for deflecting charged particles of the fluid flow (A1), wherein the particle charging device (120) and the trap electrode (130) on the first surface (1 10a) of the

Base body (1 10) are arranged.

A particle sensor (100; 100a; 100b; 100c; 10Od) according to claim 1, wherein said first surface (110a) is an outer surface of said base body (110).

A particle sensor (100; 100a; 100b; 100c; 100d) according to any one of the preceding claims, wherein the particle charging device (120) comprises a

High voltage electrode (122) for generating a corona discharge (123).

The particle sensor (100; 100a; 100b; 100c; 100d) of claim 3, wherein the particle charging means (120) includes a counter electrode (124; 124a; 124b; 124c) to the high voltage electrode (122).

The particle sensor (100; 100a; 100b; 100c; 100d) of claim 4, wherein the counter electrode (124; 124a; 124b) is also on the first surface

(1 10a) is arranged.

A particle sensor (100; 100a; 100b; 100c; 10Od) according to any one of claims 4 to 5, wherein the counter electrode (124a; 124b; 124c) is connected to the

High voltage electrode (122) simultaneously forms a counter electrode to the trap electrode (130).

7. Particle sensor (100, 100a, 100b, 100c, 10Od) according to one of claims 4 to 6, wherein the counterelectrode (124a, 124b, 124c) is at least in a first region (1241) of the counterelectrode on the first surface (110a). and wherein one of the first area (1241) is different second region (1242) of the counterelectrode (124a; 124b; 124c) protrudes from the first surface (110a).

A particle sensor (100; 100a; 100b; 100c; 100d) according to any one of the preceding claims, wherein at least one sensor electrode (140) is provided for detecting information about an electric charge flow caused by particles from the fluid flow (A1), the means of

Particle charging device (120) were charged, wherein the at least one sensor electrode (140) is also arranged on the first surface (1 10a).

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

100a; 100b; 100c; 10Od) is disposed in the inner tube (R1) of the two tubes (R1, R2) so that its first surface (110a) is oriented substantially parallel to a longitudinal axis (LA) of the inner tube (R1).

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

100d) having a base body (1 10), a particle charging device (120) for charging particles in a over a first surface (1 10a) of the base body (1 10) flowing fluid stream (A1), and a trap electrode (130) for Deflecting charged particles of the fluid stream (A1), the method comprising the steps of: providing (200) the

Main body (1 10), arranging (210) of the particle charging device (120) and the trap electrode (130) on the first surface (1 10a) of the

Basic body (1 10).