CN110998283A

CN110998283A - Particle sensor and method for producing same

Info

Publication number: CN110998283A
Application number: CN201880052795.7A
Authority: CN
Inventors: R·鲁萨诺夫
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2017-08-15
Filing date: 2018-07-31
Publication date: 2020-04-10
Also published as: WO2019034408A1; DE102017214194A1; EP3669167A1; KR20200039692A

Abstract

The invention relates to a particle sensor (100; 100a) comprising a particle charging device (110) for charging particles (P) in a fluid flow (A1) having a high voltage electrode (112) and at least one sensor electrode (120) for sensing information about the flow of electrical charge induced by the particles in the fluid flow (A1), characterized in that the sensor electrode (120) is arranged on an electrically insulating first body (102) and the high voltage electrode (112) is arranged on an electrically insulating second body (104; 104') which is different from the electrically insulating first body (102).

Description

Particle sensor and method for producing same

Technical Field

The invention relates to a particle sensor and a method for producing such a particle sensor, comprising a particle charging device having a high-voltage electrode for charging particles in a fluid flow and at least one sensor electrode for sensing information about a charge flow caused by particles, in particular charged particles, in the fluid flow.

Background

A particle sensor for use in a motor vehicle is known from WO 2013/125181 a 1. The known particle sensors have a complex layer construction with a plurality of individual layers in a relatively complex geometry.

Disclosure of Invention

The object of the present invention is therefore to improve a particle sensor of the type mentioned at the outset and a production method therefor, such that the particle sensor has increased accuracy and a relatively simple construction and can be produced cost-effectively.

This object is achieved by a particle sensor according to claim 1 and a method according to claim 10. The particle sensor according to the invention comprises a particle charging device with a high voltage electrode for charging particles in a fluid flow and at least one sensor electrode for sensing information about a charge flow caused by particles, in particular charged particles, in the fluid flow. According to the invention, the sensor electrode is arranged on an electrically insulating first body and the high voltage electrode is arranged on an electrically insulating second body, which is different from the electrically insulating first body. The arrangement of the sensor electrode and the high-voltage electrode on two different electrical insulators results in a particularly low-interference operation, in which the interference influence of the high-voltage electrode on the sensor electrode or possibly the electrical supply lines of the sensor electrode is reduced in particular in comparison to known systems. A particularly sensitive and accurate particle sensor can thereby be provided. Furthermore, a particularly simple construction and cost-effective production results. The body can also be considered as a carrier for the relevant electrode.

The fluid flow mentioned may be, for example, the exhaust gas flow of an internal combustion engine of a motor vehicle. The particles can be, for example, carbon black particles, which are produced, for example, in the framework of the combustion of fuel by internal combustion engines.

In a preferred embodiment, the first and/or second body is a Ceramic body, which can advantageously be produced, for example, by means of a Ceramic Injection Molding method (CIM). In a further preferred embodiment, the first and/or second body can also be produced using an in-mold labeling method, wherein, for example, high-voltage electrodes or sensor electrodes and/or further electrodes or electrical connecting leads and the like, if present, can advantageously be applied to the body. A relatively complex structure can thereby also be provided with relatively little manufacturing effort.

In a preferred embodiment, the particle charging device is configured for generating a corona discharge. In particular, the high-voltage electrode can also be assigned at least one counter electrode ("high-voltage counter electrode"). The corona discharge enables the charging of particles or generally particles, for example gases, in a fluid or exhaust flow in a space surrounding the high-voltage electrode. In this way, on the one hand, the particles are charged directly when they flow through the region of the corona discharge. On the other hand, the particles are charged by the charged particles of the gas or exhaust gas stream, which has been charged directly when flowing through the space in the region of the high-voltage electrode. This improves the effectiveness of the charging as a whole. In a preferred embodiment, the hv electrode has at least one needle electrode or tip.

In a preferred embodiment, the first body is configured substantially in the form of a hollow cylinder, and may therefore preferably be a cylindrical body with a hollow space along the height of the body (wherein the hollow space may also be cylindrically shaped). In a further embodiment, the base surfaces of the body and the hollow space can in particular be essentially arbitrary and differ from one another and in particular also vary in height (i.e. along the height coordinate of the body).

In a preferred embodiment, the first body has a substantially circular cross-sectional shape.

In a further preferred embodiment, the second body is constructed substantially cylindrically ("columnar"), and may therefore preferably be a columnar body. In a further embodiment, the base surface of the second body can in particular be essentially arbitrary and in particular also vary in height (i.e. along the height coordinate of the second body).

In a particularly preferred embodiment, the two bodies (first and second body) are of substantially cylindrical configuration and optionally at least one of the two bodies has a radius which varies in height.

In a further preferred embodiment, the high voltage electrode is arranged at least partially inside the inner space of the first body and the counter electrode for the high voltage electrode is arranged in particular at, in particular on, the inner surface or inner wall of the first body, whereby a particularly efficient and uniform charging of the particles is obtained.

In a further preferred embodiment, the at least one sensor electrode is arranged at, in particular on, an inner surface or wall of the first body. The sensor electrodes can be arranged, for example, in a planar manner directly on the inner surface.

In a further preferred embodiment, the second body has a maximum radial outer dimension in the first axial end region, which is smaller than a minimum radial dimension of the inner space of the first body. This advantageously makes it possible to introduce the second body at least partially, in particular with the first axial end region, into the first body in the axial direction. For example, in the case of a substantially cylindrical configuration of the basic shape of the second body, the maximum radial outer dimension can correspond to the outer diameter, wherein, if appropriate, the minimum radial dimension of the first body corresponds to the inner diameter. In this configuration, a functional space defined between a radially outer surface of the second body and a radially inner surface of the first body opposite the radially outer surface, which may for example receive an electrode of a particle charging device, is embedded by at least parts of the two bodies into each other. Optionally, one or more trap electrodes for deflecting relatively light charged particles may also be provided in this region. In embodiments in which no embedding arrangement of the two bodies with respect to one another or an embedding arrangement different from the embedding arrangement of the two bodies with respect to one another as described above by way of example is provided, at least one trap electrode can likewise optionally be provided.

In a further preferred embodiment, the electrically insulating second body is arranged substantially coaxially with the first body, in particular at least partially protruding into the first body. In addition to the definition of the functional region for the electrode already described above, a channel for conducting a fluid, for example exhaust gas, is thus advantageously defined.

In a further preferred embodiment, the high voltage electrode has at least one of the following structures: preferably a substantially planar needle-like electrode structure arranged on at least one outer surface of the second body, preferably a needle-like electrode structure arranged on at least one outer surface of the second body and protruding from, i.e. protruding from, the outer surface. A combination of these two variants is likewise possible. These embodiments enable an efficient generation of corona discharges, wherein the relevant electrode structure can at the same time be produced simply.

In a further preferred embodiment, the second body is arranged completely in the interior space of the first body, preferably held by this interior space, resulting in a particularly small-built configuration.

In a further preferred embodiment, the first body has at least one opening in a wall of the basic shape of a hollow cylinder, whereby a fluid, in particular exhaust gas or the like containing particles to be detected, can advantageously reach from the surroundings of the particle sensor into the interior space of the first body.

A subject of a further aspect of the invention is a method for manufacturing a particle sensor comprising a particle charging device with a high voltage electrode for charging particles in a fluid flow. The particle sensor has at least one sensor electrode for sensing information about a flow of electrical charge induced by particles in the fluid flow. The method has the following steps: providing an electrically insulating first body, arranging the sensor electrode on the electrically insulating first body, providing an electrically insulating second body, which is different from the electrically insulating first body, arranging the high voltage electrode on the electrically insulating second body.

Drawings

Further features, application possibilities and advantages of the invention result from the following description of an exemplary embodiment of the invention which is illustrated in the drawing. All described or illustrated features form the subject matter of the invention per se or in any combination, independently of their combination in the claims or their cited relation, and independently of their presentation in the description and in the drawings.

In the drawings:

figure 1 schematically shows a cross-section of a first embodiment of a particle sensor according to the invention,

figures 2A and 2B each schematically show a top view of a detail of a particle sensor according to a further embodiment,

figure 3 schematically shows a cross-section of a further embodiment of the particle sensor,

FIG. 4 schematically shows a simplified flow chart of an embodiment of the method according to the invention, and

fig. 5 schematically shows the arrangement of the particle sensor according to fig. 1 in a target system.

Detailed Description

Fig. 1 schematically shows a cross-section of a first embodiment of a particle sensor 100 according to the present invention. The particle sensor 100 has a particle charging device 110 for charging particles P in the fluid flow a 1. The particle charging device 110 has at least one high-voltage electrode 112, which can be charged to a relatively large potential, for example several hundred volts or several kilovolts, in order to generate a corona discharge 113. A high-voltage counter electrode 114 is associated with the high-voltage electrode 112, which can be connected to a reference potential, for example, the ground potential GND. The corona discharge 113 is particularly advantageously formed in the spatial region between the high-voltage electrode 112 and the high-voltage counterelectrode 114.

The corona discharge 113 enables charging of particles P or generally particles, such as gases, in a fluid or exhaust gas flow a1, a 1' in a spatial region surrounding the high-voltage electrode 112. The particles P are thus charged on the one hand directly when flowing through the spatial region surrounding the high-voltage electrode 112. On the other hand, the particles are charged by the charged particles of the gas or exhaust gas stream a1, a 1', which is already charged directly when flowing through the spatial region of the high-voltage electrode 112. This improves the effectiveness of the charging as a whole. In a preferred embodiment, the hv electrode 112 has at least one needle electrode or tip.

According to the invention, the particle sensor 100 also has at least one sensor electrode 120 for sensing information about a charge flow caused by particles P in the exhaust gas flow that have been charged by means of the particle charging device 110.

According to the invention, the sensor electrode 120 is arranged on an electrically insulated first body 102 and the high voltage electrode 112 is arranged on an electrically insulated second body 104, which is different from the electrically insulated first body 102. In other words, the particle sensor 100 has an electrically insulating first body 102 and an electrically insulating second body 104, which is different from the electrically insulating first body, and the

electrodes

112, 120 are respectively associated with or arranged on the

different bodies

104, 102. This advantageously results in a particularly low influence of the operation of the sensor electrode 120 by the high-voltage electrode 112, which significantly increases the accuracy and sensitivity of the particle sensor according to the invention compared to conventional configurations.

In a preferred embodiment, the first body 102 is configured substantially hollow-cylindrical, preferably with a substantially circular cross-sectional shape, thus having a sleeve shape, which provides an advantageous possibility for arranging one or more electrodes on the inner surface 102a of the first body 102.

In a further preferred embodiment, the high voltage electrode 112 is arranged at least partially inside the inner space I of the first body 102 and the high voltage counter electrode 114 is arranged in particular on the inner surface 102a or inner wall of the first body 102, thereby obtaining a particularly efficient and uniform particle charging. A relatively uniform corona discharge can be formed in the radial direction around the high-voltage electrode 112, which is preferably constructed at least approximately rotationally symmetrically (possibly except for a separate tip structure). Particularly preferably, the high voltage counterelectrode 114 is configured as a ring electrode, i.e. a section which substantially corresponds to the circumferential surface of a cylinder defined by the inner space I or the inner surface 102a of the first body 102.

In a further preferred embodiment, the at least one sensor electrode 120 is arranged on the inner surface 102a of the first body 102. The sensor electrodes 120 may, for example, be arranged facewise directly on the inner surface 102a, substantially similar to the high voltage counter electrode 114.

In a further preferred embodiment, the second body 104 has a maximum radial outer dimension in the first axial end region B1 which is smaller than a minimum radial dimension of the inner space I of the first body 102. This advantageously makes it possible to introduce the second body 104 at least partially, in particular with its first axial end region B1, axially into the first body 102. For example, in the basic shape of the substantially cylindrical configuration of the second body 104, the maximum radial outer dimension may correspond to the outer diameter D1, wherein, if necessary, the minimum radial dimension of the inner space I of the first body 102 corresponds to the inner diameter D2. In this configuration, a functional space FR, which may for example receive the

electrodes

112, 114 of the particle charging apparatus 110, is defined between a radially outer surface 104a of the second body 104 and a radially inner surface 102a of the first body 102 opposite the radially outer surface by the at least partially embedded arrangement of the two

bodies

102, 104 with each other.

Optionally, one or more trap electrodes may also be provided in this region for deflecting relatively light charged particles (ions of the gas contained in the fluid stream a1, a 1'). This results in that charged particles which do not adhere to the particles to be detected are captured before reaching the sensor electrode 120 and thus do not contribute to the charge measurement. Here, an optional trap electrode 130, which is illustrated in fig. 1 by a line drawn with a dashed line, is arranged on the outer surface 104a of the second body 104. In some embodiments, the optional trap electrode 130 may be charged to the same potential as the high voltage electrode 112, thereby advantageously requiring only a single electrical connection lead to charge the trap electrode and the high voltage electrode to a potential corresponding to the high voltage. The counter electrode 132 for the trap electrode 130 is advantageously arranged on the inner surface 102a of the first body 102, more precisely between the particle charging device 110 located further upstream and the sensor electrode 120 located further downstream with respect to the flow direction of the fluid flow a 1.

In a further embodiment (not shown in fig. 1), it can also be provided that the high-voltage electrode 112 and the trap electrode 130 are functionally combined, for example by means of a single electrode surface, which is in turn preferably arranged on the outer surface 104a of the second body 104. The separation of the

electrodes

112, 130, which can be or have been charged with a high-voltage potential, and the sensor electrode 120, which is proposed according to the invention, is advantageously maintained here by the arrangement of the electrically insulating

bodies

102, 104, which are separated from one another.

In a further embodiment (likewise not shown), which does not provide for a mutually embedded arrangement of the two

bodies

102, 104 or for an embedded arrangement which differs from the mutually embedded arrangement of the two bodies described above by way of example, at least one trap electrode can likewise optionally be provided.

In a further preferred embodiment, the electrically insulating second body 104 is arranged substantially coaxially with the first body, in particular at least partially protruding into the first body 102, as is exemplarily depicted in fig. 1. Here, the first axial end region B1 of the second body 104 projects into the interior space I of the first body 102, whereas the second axial end region B2 of the second body 104 does not project into the interior space I and if appropriate has an outer diameter which is greater than the first outer diameter D1. In addition to the above-described definition of the functional regions or functional spaces FR for the

electrodes

112, 114, 130, channels K for conducting a fluid, for example exhaust gas, are thus advantageously defined. The fluid exiting the particle sensor 100 is indicated by reference character a 2.

In a further embodiment, an optional shielding electrode 140, for example in the form of a grid electrode, is provided, which is preferably arranged between the particle charging device 110 and the sensor electrode 120. If an optional trap electrode 130 is provided, an optional shielding electrode 140 is preferably also arranged between the optional trap electrode 130 and the sensor electrode 120, as schematically indicated in fig. 1. The shielding electrode 140 may advantageously be used to shield the sensor electrode 120 from electric fields generated by components arranged further upstream (e.g. electric fields generated by the corona discharge 113).

Particularly preferably, the particle sensor is configured in some embodiments substantially rotationally symmetrically, so that the sensitivity with respect to the installation angle in the target system is reduced.

In a further preferred embodiment (top view corresponding thereto is described in detail below with reference to fig. 2A, 2B), the high voltage electrode 112 (fig. 1) has at least one of the following structures: a substantially planar needle-like electrode structure 1120 (fig. 2A), preferably arranged on the outer surface 104a of the second body 104, a needle-like electrode structure 1122 (fig. 2B), preferably arranged on the outer surface 104a of the second body 104 and protruding, in particular perpendicularly (here also perpendicularly to the drawing plane of fig. 2B), from the outer surface 104a, i.e. protruding from the outer surface. A combination of these two variants is likewise conceivable. These embodiments enable an efficient generation of a corona discharge, wherein at the same time the relevant electrode structure can be produced simply. The top views according to fig. 2A, 2B show, in particular, the outer surface 104a of the second body 104, in a viewing direction in the radially inner direction of the particle sensor 100, wherein additionally a part of the respective high voltage counter electrode 114 is schematically shown. Fig. 2B additionally schematically shows an electrical connection lead 110' for a high voltage electrode with its needle electrode structure 1122.

In an embodiment, the needle-like electrode structure 1120 according to fig. 2A may be manufactured, for example, by means of screen printing, in particular platinum screen printing, i.e. by printing onto the second body 104. In a further embodiment, it can be provided that the needle electrode structure 1120 is alternatively or additionally produced by means of an in-mold labeling method, which further simplifies the production and is more cost-effective.

Particularly preferably, in some embodiments, the needle-like electrode structure 1120 is shaped in such a way that the needle-like tip (the region of the needle-like electrode structure with the smallest bending radius) ends essentially, preferably as precisely as possible, in the region of the high-voltage counter electrode 114, in particular with respect to the longitudinal axis of the particle sensor, as a result of which the corona discharge 113 is produced just at this point.

In an embodiment, the needle-like electrode structure 1122 according to fig. 2B may be produced, for example, by a corresponding 3D (three-dimensional) shaping of the "needles" on the second body 104, for example below the electrode area produced by means of an in-mold labeling process, and/or by subsequently placing the "needles" on a flat electrode area. For example, the arrangement of a ring-shaped electrically conductive (metal) element with a needle-like tip on the inner body 104 and the electrical connection of this element to a connecting line for supplying a potential corresponding to a high voltage can be considered.

Fig. 3 schematically shows a cross section of a further embodiment 100a of the particle sensor, in which the second body 104 'is of a different design than the design 100 according to fig. 1, wherein the second body 104' in the embodiment 100a according to fig. 3 is arranged in particular completely in the interior I of the first body 102, resulting in a particularly small design. Preferably, the second body 104' is also held by the first body 102, which results in a particularly simple configuration. Here, the outer, for example ceramic, carrier formed by the first body 102 is of substantially horizontally "continuous" design in fig. 3 (for example up to a mounting cartridge, not shown, which enables installation in the target system and can be arranged here, for example, on the left end of the first body 102 in fig. 3).

In a further preferred embodiment, the first body 102 has at least one opening 1022 in a hollow cylindrical wall 102 'of basic shape, whereby a fluid, in particular an exhaust gas or the like containing particles P' to be detected, can advantageously reach from the surroundings U of the particle sensor 100a into the interior space I of the first body 102. Optionally, a substantially tubular guide element 1020, in particular a guide tab, may also be arranged on the radial outside of the first body 102, which guide element leads to a guidance of the fluid or fluid flow a1, a 1' from the surroundings U through the opening 1022 into the interior space I.

In the configuration 100a shown in fig. 3, as a further difference from the configuration 100 according to fig. 1, a combined high-voltage and trap electrode 112a is provided, which in turn can be charged with a larger potential and which can have, for example, a needle-

like structure

1120, 1122 to form a corona discharge between the combined high-voltage and trap electrode 112a and the respective counter electrode 1140. The counter electrode 1140 is preferably arranged on the inner surface 102a of the first body 102.

In some embodiments, the combined high voltage and trap electrode 112a may also be constructed, for example, as a discrete component, in particular a metallic conductive element or an element with a metallic conductive surface, which may be inserted, for example, into a radially inner opening of the second body 104'. In a further embodiment, a plurality of electrodes for realizing at least one high voltage electrode and at least one trap electrode may also be provided. In this case, for example, a further electrically insulating element may be provided or arranged in the second body 104'.

The electrical connection leads 120' for the sensor electrodes 120 are advantageously arranged on the inner surface 102a of the first body 102 and are thus spatially separated from the "high-voltage components" 112a, 1120, 1122. Electrical connection leads 1140' for the counter electrodes 1140 can be arranged on the inner surface 102a in a similar manner. In particular, the supply lines of the sensor electrodes can run insulated (for example, produced by means of a multi-layered screen-printed structure) below the counter electrode 1140 and can shield the interference generated by the corona discharge.

A further important advantage of the configuration 100a according to fig. 3 is that no electrical contact between the two bodies 102, 104' is required for electrically connecting wires or a continuation of the supply wires to the holder or fitting cartridge, which further simplifies the construction.

A subject matter of a further aspect of the invention is a method for manufacturing a

particle sensor

100, 100a, for example according to the previously described embodiments, which method is described below with reference to a simplified flowchart according to fig. 4. The method has the following steps: a first electrically insulating body 102 is provided 200 (fig. 1, for example using ceramic casting), a sensor electrode 120 is arranged 202 (fig. 4) on the first electrically insulating body 102, a second electrically insulating body 104 is provided 204, which is different from the first electrically insulating body 102, and a high voltage electrode 112 is arranged 206 on the second electrically insulating body 104.

Fig. 5 schematically shows the arrangement of the particle sensor 100 according to fig. 1 in a target system, which is here an exhaust pipe R of an internal combustion engine of a motor vehicle. The particle sensor 100 is arranged in a protective tube arrangement comprising a radially outer first tube R1 and a radially inner second tube R2, which is arranged radially inside the first tube R1 and, if necessary, is arranged partially offset in the axial direction from the first tube R1, as can be seen from fig. 5. Due to the different lengths of the tubes R1, R2 and the arrangement relative to each other, a vortex (Sog) is created by the venturi effect in which the exhaust gas flow a causes a fluid flow P1 or a1 (fig. 1) out of the inner tube R1, in the vertical direction in fig. 5. Further arrows P2, P3, P4 indicate the continuation of this fluid flow caused by the venturi effect through the intermediate space between the two tubes R1, R2 to the surroundings U' of the protective tube assembly. Overall, the arrangement illustrated in fig. 5 results in a comparatively uniform flow through the particle sensor 100, which enables an effective sensing of particles located in the fluid flow P1. Furthermore, the particle sensor 100 is protected against direct contact with the primary exhaust flow a. The sensor device 1000 for determining the particle concentration in the exhaust gas a is therefore advantageously specified by the elements 100, R1, R2.

In a further preferred embodiment, the function of the radially outer tube R2 can also be fulfilled by the tubular guide element 1020 according to fig. 3, wherein the first body 102 of the particle sensor 100a according to fig. 3 can advantageously assume the function of the inner tube R1, thereby further simplifying the configuration. In such an embodiment, it is further advantageous if one or more openings 1022 are arranged circumferentially or annularly in the first body 102 in order to be able to introduce a fluid containing particles (for example exhaust gas) into the interior space I (fig. 3) of the particle sensor, where the particles are first charged and then the charge of the particles is measured.

The operating principle of the

particle sensor

100, 100a according to the described embodiment is based on the charging of the particles P to be measured (fig. 1), in particular carbon black particles, and the subsequent detection of this charged charge by the sensor electrode 120. The particle sensor can be used advantageously, for example, for monitoring a diesel particle filter of a self-igniting internal combustion engine. The mass concentration (mg/m) of the carbon black particles P can be determined, for example, by means of a particle sensor³Or mg/mi) and/or number concentration (particles/m)³Or particles/mi). The ability to measure quantitative concentrations according to some embodiments is just particularly advantageous here, since this may only be insufficiently accurate for some purposes of use in conventional systems.

In a further embodiment, the particle sensor can also be used, for example, in vehicles with internal combustion engines with external ignition, for example "gasoline vehicles", in order to detect particle emissions there. It is important for example to be able to measure quickly right there after the start of the vehicle or internal combustion engine, since a large proportion of particles are produced during a cold start. Particle number measurement capability is also particularly important for gasoline vehicles due to the fine particles (small mass, large number).

In this respect, the particle sensor according to the exemplary embodiment is also particularly advantageous, since conventional vehicle sensors (on-board) currently available on the market are not able to reliably measure the particle count.

As already described above, a preferred embodiment of the particle sensor according to the invention is based on the detection of the charge (or corresponding current) of the previously charged carbon black particles P (fig. 1). In this case, the charging is preferably effected by means of a corona discharge in the air or in the particle-containing fluid stream a1, the measurement of the charge being effected, for example, by the "escape current" principle or by charge induction (the charge characterizing the particles or a measurement signal of the corresponding current being sensed by the sensor electrodes 120). According to some embodiments, the particle sensor may be particularly advantageously used for ODB (on-board diagnostics) monitoring of the state of the diesel particulate filter as legally prescribed.

Additional fields of application, such as the use in the exhaust system before (i.e. upstream of) the diesel particulate filter, may also be considered to optimize engine control. A much higher sensitivity (minimum measurable particle or soot concentration) is achieved by the new measuring principle, which cannot be achieved by the impedance-type principle hitherto (measuring the current flowing due to soot). The much higher measurement speed (at least 1 measurement per second compared to several minutes per measurement) and the possibility of particle count measurement that can be achieved according to the present invention are also important advantages of the

particle sensor

100, 100 a. This also enables the use of GPF (particulate filter for gasoline vehicles) monitoring in gasoline vehicles. The higher measurement speed also allows, in particular, a correlation of the raw measurement signal with the engine operating point, which leads to an improvement in the data evaluation and thus to an increase in the sensor accuracy.

The principles of the described

embodiments

100, 100a are particularly directed to the problem of reducing the disturbing influence of the high voltage electrodes and the high voltage electrode supply leads on the sensor electrode 120 and its supply leads. For this purpose, the above-described design with two

separate bodies

102, 104, for example bodies made of ceramic material, is proposed. Advantageously, the

bodies

102, 104 can be manufactured by means of Ceramic Injection Molding (CIM), in particular by in-mold labeling, which also allows relatively complex geometries to be realized with little manufacturing effort.

Furthermore, the concept presented here has some further advantages over further forms of construction. The separation of the high-voltage and low-voltage components or the distribution thereof on the two different bodies or

carriers

102, 104 brings the advantage of sensitivity and accuracy for the particle sensor. The corona discharge, which is arranged in a ring shape and can be realized in a preferred embodiment, increases the amount of charged carbon black particles (the effective cross section is larger) and thus increases the sensitivity of the sensor. The annular arrangement additionally strongly reduces the sensitivity of the

particle sensor

100, 100a with respect to the installation angle (see fig.), which simplifies the assembly in the target system 1000. The same also applies to the ring-shaped

trap electrodes

130, 132 and their electric fields in the preferred embodiment, thereby improving the uniformity of the traps (trapping relatively light charged particles).

The particle sensor according to the exemplary embodiments can be used, for example, as a sensor for on-board monitoring of the state of a diesel particle filter of a passenger or commercial vehicle. The concept is able to achieve both mass concentration (mg/m)³Or mg/mi) can also be achieved³Or particles/mi). Furthermore, the particle sensor according to the embodiment can also be used for condition monitoring of a particle filter in a gasoline vehicle. The use of sensors for determining the particle concentration in other applications (indoor air quality, (emissions of private, industrial) combustion facilities) may also be considered.

Claims

1. Particle sensor (100; 100a) comprising a particle charging device (110) having a high voltage electrode (112) for charging particles (P) in a fluid flow (a1) and at least one sensor electrode (120) for sensing information about the flow of electrical charge caused by particles (P), in particular charged particles, in the fluid flow (a1), characterized in that the sensor electrode (120) is arranged on an electrically insulating first body (102) and the high voltage electrode (112) is arranged on an electrically insulating second body (104; 104') which is different from the electrically insulating first body (102).

2. A particle sensor (100; 100a) according to claim 1, wherein the first body (102) is substantially hollow cylindrically configured.

3. A particle sensor (100; 100a) according to claim 2, wherein the first body (102) has a substantially circular cross-sectional shape.

4. A particle sensor (100; 100a) according to claim 2 or 3, wherein the high voltage electrode (112) is arranged at least partially inside the inner space (I) of the first body (102) and, in particular, a counter electrode (114) for the high voltage electrode (112) is arranged at the inner surface (102a), in particular on the inner surface (102a), of the first body (102).

5. Particle sensor (100; 100a) according to at least one of claims 2 to 4, wherein the at least one sensor electrode (120) is arranged at an inner surface of the first body (102) or the inner surface (102a), in particular on the inner surface (102 a).

6. A particle sensor (100; 100a) according to at least one of claims 2 to 5, wherein the second body (104) has a largest radial outer dimension (D1) in the first axial end region (B1) which is smaller than a smallest radial dimension (D2) of an inner space of the first body (102) or of the inner space (I).

7. Particle sensor (100; 100a) according to at least one of the preceding claims, wherein the electrically insulating second body (104; 104') is arranged substantially coaxially with the first body (102), in particular at least partially protruding into the first body (102).

8. Particle sensor (100; 100a) according to at least one of the preceding claims, wherein the high voltage electrode (112) has at least one of the following structures: preferably a substantially planar needle-like electrode structure (1120) arranged on at least one outer surface (104a) of the second body (104), preferably a needle-like electrode structure (1122) arranged on at least one outer surface (104a) of the second body (104) and protruding from said outer surface (104 a).

9. A particle sensor (100; 100a) according to at least one of claims 2 to 7, wherein the second body (104') is arranged completely in an inner space of the first body (102) or the inner space (I), preferably held by the inner space.

10. A particle sensor (100; 100a) according to at least one of claims 2 to 8, wherein the first body (102) has at least one opening (1022) in a wall (102') having the basic shape of a hollow cylinder.

11. Method for manufacturing a particle sensor (100; 100a) comprising a particle charging device (110) having a high voltage electrode (112) for charging particles (P) in a fluid flow (a1) and at least one sensor electrode (120) for sensing information about a charge flow induced by the particles of the fluid flow (a1), characterized in that the method comprises the steps of: -providing (200) an electrically insulating first body (102), -arranging (202) the sensor electrode (120) on the electrically insulating first body (102), -providing (204) an electrically insulating second body (104; 104 ') different from the electrically insulating first body (102), -arranging (206) the high voltage electrode (112) on the electrically insulating second body (104; 104').