DE102018207789A1 - Sensor arrangement for detecting particles of a measuring gas in a measuring gas space and method for detecting particles of a measuring gas in a measuring gas space - Google Patents

Abstract

A sensor arrangement (110) for detecting particles of a measurement gas in a measurement gas space is proposed. The sensor arrangement (110) comprises: • at least one sensor element (112) having at least one first electrode structure (116) and at least one second electrode structure (120), wherein the first electrode structure (116) has at least one first supply line (118); Control unit (124), wherein the control unit (124) comprises at least one measuring device (126); characterized in that the measuring device (126) is set up in order to change the electrical properties of the sensor element caused by an accumulation of the particles between the first electrode structure (116) and the second electrode structure (120) by measuring a voltage drop across at least one measuring resistor (145). to detect at the first electrode structure (116); and the first electrode structure (116) has at least one second lead (122), the control unit (124) further comprising at least one first test device (128), the first test device (128) being arranged to connect the first electrode structure (116) over the first electrode second supply line (122) to act upon a first test signal and to detect a first response signal of the first electrode structure (116) via the first supply line (118).

Description

State of the art

The prior art discloses a multiplicity of sensor arrangements for detecting particles of a measurement gas in a measurement gas space. For example, the measuring gas may be an exhaust gas of an internal combustion engine. In particular, the particles may be soot or dust particles. The invention will be described below without limiting further embodiments and applications, in particular with reference to sensor elements for the detection of soot particles.

Two or more metallic electrodes may be mounted on an electrically insulating support. The accumulating under the action of a voltage particles, in particular the soot particles, form in a collecting phase of the sensor element electrically conductive bridges between the example designed as a comb-like interdigitated interdigital electrodes and close this short. In a regenerating phase, the electrodes are usually baked by means of an integrated heating element. In general, the particle sensors evaluate the changed due to the particle accumulation electrical properties of an electrode structure. For example, a decreasing resistance or current at constant applied voltage can be measured.

Sensor arrays operating according to this principle are generally referred to as resistive sensors and exist in a variety of embodiments, such as DE 10 2005 053 120 A1 . DE 103 19 664 A1 . DE10 2004 0468 82A1 . DE 10 2006 042 362 A1 . DE 103 53 860 A1 . DE 101 49 333 A1 and WO 2003/006976 A2 known. The configured as soot sensors sensor assemblies are commonly used to monitor diesel particulate filters. In the exhaust system of an internal combustion engine, the particle sensors of the type described are usually accommodated in a protective tube which simultaneously allows, for example, the flow through the particle sensor with the exhaust gas.

Due to increasing environmental awareness and partly due to legal regulations, the soot emissions must be monitored while driving and the functionality of the monitoring must be ensured. This type of functionality monitoring is commonly referred to as on-board diagnostics. Devices and methods for self-diagnosis of a particle sensor are for example DE 10 2009 028 239 A1 . DE 10 2009 028 283 A1 . DE 2007 046 096 A1 and US 2012/0119759 A1 known.

Despite the advantages of the prior art sensor arrangements for detecting particles, these still contain room for improvement. Thus, in particular the legally required self-monitoring of the soot sensor in terms of electrical functionality is usually difficult to implement. In particular, a continuous monitoring, preferably with a fixed predetermined minimum frequency, such as a monitoring with at least 2 Hz, often presents a challenge. Furthermore, partial damage, which can lead to a loss of sensitivity, usually not or not recognized as such. Furthermore, parasitic effects, such as a superposition of a signal of the sensor array by a parasitic current, which may depend on a temperature and / or aging of a resistor used, complicate the self-diagnosis. Often a separation of the particle-related signal from an offset signal is still not clearly possible, so that the self-diagnosis is difficult during the loading of the sensor element with particles.

Disclosure of the invention

In the context of the present invention, therefore, a sensor arrangement for detecting particles of a measuring gas in a measuring gas space is proposed. The sensor arrangement comprises at least one sensor element with at least one first electrode structure and at least one second electrode structure. The first electrode structure has at least one first supply line. Furthermore, the sensor arrangement comprises at least one control unit. The control unit comprises at least one measuring device. The measuring device is set up to detect a change in electrical properties of the sensor element caused by an accumulation of the particles on the electrode structure by measuring a voltage drop across at least one measuring resistor on the first electrode structure. Furthermore, the control unit comprises at least a first test device. The first test device is set up to apply a first test signal to the first electrode structure via the first supply line, in particular to apply it in a switchable manner, and to detect a first response signal of the first electrode structure via the second supply line. Furthermore, the control unit may comprise at least a second test device. The second test device can be set up to act on the second electrode structure in particular switchably with a second test signal and to detect a second response signal of the second electrode structure.

In the context of the present invention, a "sensor arrangement" can basically be understood to mean any device which is set up to detect at least one measured variable of the measurement gas. Accordingly, in the context of the present invention, a "sensor arrangement for detecting particles of a measuring gas" can basically be understood to mean any device which is suitable for qualitatively and / or quantitatively detecting the particles in the measuring gas and which, for example, with the aid of a suitable control unit and suitably designed electrodes can generate at least one electrical measurement signal corresponding to the detected particles, such as a voltage or a current. The detected particles may in particular be soot particles and / or dust particles. In this case, DC signals and / or AC signals can be used. Furthermore, for example, a resistive component and / or a capacitive component can be used for signal evaluation from the impedance.

The sensor arrangement can be set up in particular for use in a motor vehicle. In particular, the measuring gas may be an exhaust gas of the motor vehicle. Other gases and gas mixtures are possible in principle. In the context of the present invention, an exhaust gas is understood in particular to mean gaseous waste products in a combustion process, which may also include solid and / or liquid admixtures, for example in the form of particles and / or droplets. In principle, the measurement gas space can be any, open or closed space in which the measurement gas is received and / or which is flowed through by the measurement gas. For example, the measuring gas space may be an exhaust gas tract of an internal combustion engine, for example an internal combustion engine.

Under an internal combustion engine according to the present invention is a basically arbitrary device to understand, which can support or carry out a combustion process. In particular, it may be a device with at least one combustion chamber. In particular, it may be a heat engine, by means of which by combustion of at least one fuel chemical energy is converted into mechanical energy. As an example, internal combustion engines are mentioned, especially diesel engines. However, other types of combustion engines are basically usable.

For the purposes of the present invention, particles within the scope of the invention are generally particles which have a small dimension in comparison with the system under consideration, in particular the internal combustion engine or an exhaust system of the same. In particular, the particles may have a particle size or average particle size of less than one millimeter, typically less than 1 micrometer. For example, the particles may be particles with an average particle size of 20 nanometers to 300 nanometers. In principle, these may be electrically insulating and / or electrically conductive particles, such as soot or dust particles. In particular, carbon black can be a black solid that consists largely of carbon.

In the context of the present invention, a "sensor element" can in principle be understood as any device which can serve as a functional unit, for example for a sensor arrangement, and as such can generate at least one measuring signal, for example the at least one electrical measuring signal corresponding to the detected particles.

In the context of the present invention, an "electrode structure" can basically be understood as meaning any one or more electrical conductors which are suitable for current measurement and / or voltage measurement and / or which have at least one element in contact with the electrode structure with a voltage and / or can apply a current. The electrode structure may in particular comprise one or more electrode fingers. In the context of the present invention, an "electrode finger" can basically be understood to mean any shape of the electrode structure whose dimensions in one dimension clearly exceed a dimension in at least one other dimension, for example at least a factor of 2, preferably at least a factor of 3 preferably at least a factor of 5. The electrode finger may in particular have an electrode finger shape. For example, the electrode finger mold may comprise at least one of the following shapes: a loop, in particular an open or closed loop; a loop, in particular an open or closed loop; a turn; a snake shape; an S-shape; a meander shape. In the context of the present invention, a loop can basically be understood to mean a shape which has a bend. In particular, this may be a strong bend, so that the object having the bend has a circular or spiral shape. The first electrode structure and / or the second electrode structure may in particular be formed as continuous loops.

The terms "first electrode structure" and "second electrode structure" are as pure Describe descriptions without indicating an order or ranking and, for example, without precluding the possibility that several types of first electrode structures and / or second electrode structures or each of exactly one type may be provided. Furthermore, additional electrode structures, for example one or more third electrode structures may be present.

The second electrode structure can be set up for a temperature measurement. The sensor element may further comprise at least one further device. The further device may in particular be a heating device. Furthermore, the further device may be at least one temperature measuring device. The second electrode structure may comprise all or part of the further device. In particular, the second electrode structure, and the further device may be placed in a common ground path. The second electrode structure may be configured for detecting the particles of the measurement gas in the measurement gas space. Furthermore, the second electrode structure can be set up for a temperature measurement. A particular desired functionality can be adjusted by means of switching, for example by means of a switch, in particular by means of a semiconductor switch.

The terms "first supply line" and "second supply line" are to be regarded as pure descriptions without indicating an order or ranking and excluding, for example, without the possibility that several types of first supply lines and / or second supply lines or just one type may be provided. Furthermore, additional supply lines, for example, one or more third leads may be present. The term "supply line" basically denotes any electrical line which is set up for the transport of electrical energy. In particular, it may be a conductive connection between electrical components. The supply line may in particular comprise one or more metallic electrical conductors, usually in the form of wires or strands, but also of strips or rails, for example of copper or aluminum. Other embodiments are conceivable in principle.

In the context of the present invention, a "measuring device" can basically be understood to mean any device which is set up to detect at least one electrical signal. In particular, the measuring signal may be at least one measuring signal of the sensor arrangement, in particular of the sensor element, corresponding to the detected measured variable. In particular, the measuring signal may be at least one electrical measuring signal, for example a voltage or a current, corresponding to the detected particles. The measuring device can be set up to apply a basic electrical signal to the first electrode structure, wherein the first test signal and / or the second test signal is superimposed on the electrical base signal. The first test device and / or the second test device can be coupled to the measuring device, so that can be superimposed on the electrical signal to the test signal from an electrical base signal generated by the measuring device.

In the context of the present invention, an "electrical property" of a device may in principle be understood to be any feature or arbitrary nature of the device which influences at least one electrical variable, for example a voltage or a current flow, if the device is part of an electrical circuit , In particular, the electrical property may be a resistor or an impedance. In particular, electrically conductive soot bridges between the electrode devices can influence the electrical properties of the electrode structure, in particular its resistance.

In the context of the present invention, a "test device" may in principle be understood as any device which is set up to control or monitor at least one property, in particular the functional state, of another device, in particular a device electrically connected to the test device. The terms "first tester" and "second tester" are to be considered as pure descriptions without indicating an order or ranking, for example, without precluding the possibility that several types of first test devices and / or second test devices, or each of exactly one type, may be provided. Furthermore, additional test devices, for example, one or more third test devices may be present.

The first test device and / or the second test device can be set up to detect defects of the first electrode structure or of the second electrode structure. In the context of the present invention, a "defect" of a device can basically be understood to mean a restriction or a failure of the functional capability of the device. Accordingly, a "defect of the first electrode structure or of the second electrode structure" can be understood as meaning that the sensor element can not produce the at least one measurement signal, for example the at least one electrical measurement signal corresponding to the detected particles, for example delayed, not in the provided strength or not according to the particles to be detected. In particular, a break or a Damage to the at least one first electrode finger or the at least one second electrode finger or a faulty arrangement of the electrode fingers to one another, for example in the form of a short circuit, lead to the defect of the sensor element.

In the context of the present invention, a "test signal" can basically be understood to mean any electrical signal, in particular a voltage signal or a current signal, with which a device is subjected for the purpose of checking the functional state of the device. The first test signal and / or the second test signal can be time-changeable or even constant. The first test device and / or the second test device may be configured to detect a response signal of the first electrode structure or of the second electrode structure and to close the response signal to a functional state of the first electrode structure or of the second electrode structure. In the context of the present invention, a "response signal" can basically be understood as meaning an electrical signal of a device which is caused by an electrical signal which precedes the response signal, with which the device or another device in electromagnetic contact with it was subjected. In particular, the electrical signal preceding the response signal in time may be the test signal.

The term "switchable" basically means that any combination of individual electrical elements and / or individual electromechanical elements can be controlled to form a functionally correct arrangement. The combination may be usable by an electric current through the individual electrical elements and / or individual electromechanical elements. In this case, the individual electrical elements and / or electromechanical individual elements can be connected to one another by one or more electrical lines and by means of an electrical switch can be changed between two different states. In a first state, the individual electrical elements and / or individual electromechanical elements can be connected to one another by one or more electrical lines and the connection can be set up in such a way that a current flows through the individual electrical elements and / or individual electromechanical elements. In a second state, the individual electrical elements and / or electromechanical individual elements can not be connected to one another by one or more electrical lines and the combination can be set up such that a current flow through the individual electrical elements and / or individual electromechanical elements does not take place or is at least reduced. The terms "first state" and "second state" are to be regarded as pure descriptions without indicating a sequence or precedence and, for example, without precluding the possibility that several types of first states and / or second states or in each case exactly one species may be provided. Furthermore, additional states, for example one or more third states may be present. The first test device may have at least one electrical switch. The first test device may have at least one load resistor. The term "load resistance" basically refers to any electrical resistance that is set up to load an electrical energy source and / or an electrical signal source. The load resistor may be configured to determine and / or adjust an electrical current and / or electrical power supplied by a source. The load resistor may therefore also be an AC resistor and / or an impedance which is composed of an effective resistance and a reactance. Other embodiments are conceivable in principle.

As already stated above, the control unit can continue to have the second test device. The second test device can be set up to apply the second test signal to the second test signal, in particular to apply it in a switchable manner, and to detect a second response signal of the second electrode device. The second test device may have at least one further load resistor.

The control unit may further comprise at least one measuring resistor. The term "measuring resistor" basically refers to any resistor which can be used for measuring an electric current. Therefore, an electric current which is set to be tiled by the measuring resistor may cause a voltage drop proportional to a magnitude of the electric current. The measuring resistor may have an AC resistance of 100 Ω to 100 kΩ, preferably 1 kΩ to 10 kΩ. The measuring resistor can therefore also be called a measuring resistor, shunt or measuring shunt. Furthermore, the measuring resistor may comprise at least one operational amplifier. The term "operational amplifier" basically refers to any electronic amplifier having a gain of 1 or greater than 1. The measuring device may be configured to detect the voltage drop by means of the operational amplifier.

The sensor arrangement comprises, as already stated above, the control unit. The control unit comprises, as already stated above, the Measuring device, the first test device and the second test device. Furthermore, the control unit can have at least one electrical energy source and at least one processor or circuit which can exert a control function and / or evaluation function of at least one measurement signal and / or response signal generated with the sensor arrangement, in particular with the sensor element. In particular, the measuring device can be designed to apply an electrical base signal to the first electrode structure and / or the second electrode structure, wherein the first test signal or the second test signal can be superimposed on the electrical base signal. In the context of the present invention, an "electrical base signal" can basically be understood to mean any electrical signal, in particular a voltage signal or a current signal applied to an electrode structure, in particular for the purpose of generating an electrical measurement signal according to the detected particles. In particular, the electrical base signal can serve to detect the electrical properties of the sensor element, in particular of the electrode structure, and thus also the change in the electrical properties of the sensor element, in particular of the electrode structure. Since the changes in the electrical properties of the sensor element, in particular the electrode structure, caused by the attachment of the particles to the electrode structure serve to detect the particles, the electrical base signal can serve in particular for generating an electrical measurement signal according to the detected particles. The basic electric signal may in particular be a continuous electrical signal. Furthermore, the measuring device can have at least one voltage source for acting on the electrode structure with a base voltage and at least one current measuring device for measuring a current of the electrode structure. In particular, the base voltage may be the electrical base signal.

The first test device and / or the second test device may have at least one electrical energy source. In particular, the first test apparatus and / or the second test apparatus can have at least one current source and / or voltage source, in particular a pulsed electrical energy source, for generating the test signal. In particular, the first test signal and / or the second test signal may comprise at least one voltage signal. In particular, the first test signal and / or the second test signal may have a frequency of at least 2 Hz. The first test device and / or the second test device may further comprise at least one detection device for detecting the response signal, in particular a voltage measuring device and / or a current measuring device. The first test device and / or the second test device may further comprise at least one electrical element selected from the group consisting of: a capacitor; a capacity; a resistance; a coil; a coil pair. In particular, the electrical element can couple the test device to the measuring device and / or the electrode structure, so that the test signal can be superimposed on the electrical base signal generated by the measuring device via the electrical element.

In the context of the present invention, a meander-shaped course can basically be understood to mean any course which has at least one S-shape or at least one snake-shape or at least one turn. The electrode fingers can be designed in particular as continuous loops. The sensor assembly may be configured to monitor an electrical continuity of the electrodes.

Furthermore, the sensor element may comprise a heater. In particular, the heater can be set up to free the sensor element, in particular the first electrode device and the second electrode device, from the particles, in particular the soot particles.

In a further aspect of the present invention, a method for detecting particles of a measurement gas in a measurement gas space is proposed. The method comprises a use of the sensor arrangement, as has already been described or will be described below. The method comprises the following steps, preferably in the order given. Also a different order is possible. Furthermore, one or more or all of the method steps can also be carried out repeatedly. Furthermore, two or more of the method steps may also be performed wholly or partially overlapping in time or simultaneously. The method may, in addition to the method steps mentioned, also comprise further method steps.

1. a) Erfassen mindestens eines Messsignals, wobei mittels des Messsignals eine durch eine Anlagerung der Partikel an der Elektrodenstruktur bedingte Änderung elektrischer Eigenschaften des Sensorelements erfassbar ist; und
2. b) Durchführung mindestens einer Überprüfung eines Funktionszustands mindestens einer Elektrodenstruktur ausgewählt aus der Gruppe bestehend aus: der ersten Elektrodenstruktur, der zweiten Elektrodenstruktur.

The method comprises the following steps:

1. a) detecting at least one measuring signal, wherein by means of the measuring signal a caused by an accumulation of the particles on the electrode structure change of electrical properties of the sensor element can be detected; and
2. b) performing at least one check of a functional state of at least one electrode structure selected from the group consisting of: the first electrode structure, the second electrode structure.

1. i. Beaufschlagen der ersten Elektrodenstruktur mit einem ersten Prüfsignal;
2. ii. Erfassen eines Antwortsignals auf das erste Prüfsignal;
3. iii. Auswerten des Antwortsignals und Erzeugen mindestens einer Information bezüglich eines Funktionszustands der ersten Elektrodenstruktur.

Step b) may in particular comprise the following steps:

1. i. Applying a first test signal to the first electrode structure;
2. ii. Detecting a response signal to the first test signal;
3. iii. Evaluating the response signal and generating at least one information regarding a functional state of the first electrode structure.

1. I. Beaufschlagen der zweiten Elektrodenstruktur mit einem zweiten Prüfsignal;
2. II. Erfassen eines Antwortsignals auf das zweite Prüfsignal;
3. III. Auswerten des Antwortsignals und Erzeugen mindestens einer Information bezüglich eines Funktionszustands der zweiten Elektrodenstruktur.

Furthermore, step b) may comprise the following steps:

1. I. applying the second electrode structure with a second test signal;
2. II. Detecting a response signal to the second test signal;
3. III. Evaluating the response signal and generating at least one information regarding a functional state of the second electrode structure.

The steps I.-III , can be performed in particular during a temperature measurement. The time-varying first test signal and / or the time-varying second test signal in step i. or. I , may in particular comprise at least one voltage signal. In particular, the voltage signal may comprise at least one element selected from the group consisting of: a capacitively generated voltage signal; an electrically, in particular resistively, generated voltage signal; an inductively generated voltage signal. Furthermore, the application of a first or second test signal to the first electrode structure and / or second electrode structure in step i. or. I. with a frequency of at least 2 Hz. Furthermore, the response signal in step ii. or. II , comprise at least one capacitive signal. Furthermore, the evaluation of the response signal in step iii. or. III , comprising comparing the response signal with a predetermined response threshold. Furthermore, in step iii. or. III , the first electrode structure and the second electrode structure are classified as intact when the response signal is greater than the predetermined threshold, and the first electrode structure and the second electrode structure can be classified as erroneous if the response signal is less than or equal to the predetermined response threshold.

Advantages of the invention

The sensor arrangement according to the invention and the described methods have numerous advantages over conventional sensor arrangements and methods of the type mentioned. The sensor arrangement according to the present invention can basically meet the legal CARB specification "2 Hz diagnosis". Furthermore, a Rußmessstrecke be checked. Already known sensor arrangements can in principle have a terminating resistor for carrying out the 2 Hz diagnosis. In this case, in principle, an actual sensor signal can be superposed on having a high leakage current or offset, which may be due to the terminating resistor. This can lead to a higher variance of a sensor trip time. The method for detecting particles of a measuring gas in a measuring gas chamber according to the present invention may have the possibility to place the second electrode device, in particular a negative IDE electrode in a common ground branch, in particular a heater and / or temperature meander ground branch and second supply line The first electrode device can be used as a liberated line for an IDE loop diagnosis. A particular desired functionality, such as a soot measurement, a temperature measurement, a heating, can be made possible by means of switching, for example by means of a semiconductor switch. Another legal requirement is basically the so-called "monitoring capability". After this, it should always be recognized by self-diagnosis whether a soot measurement capability and thus the sensitivity of the sensor device is limited. The electrode device can in principle be designed as a continuous snake structure. A possible interruption of individual subregions can be recognized immediately.

list of figures

Further details and optional features of the invention are shown in the embodiments which are shown schematically in the following drawings.

• 1 ein Ausführungsbeispiel einer erfindungsgemäßen Sensoranordnung, und
• 2 ein Flussdiagramm eines erfindungsgemäßen Verfahrens zum Erfassen von Partikeln eines Messgases in einem Messgasraum.

Show it:

• 1 an embodiment of a sensor arrangement according to the invention, and
• 2 a flow chart of a method according to the invention for detecting particles of a sample gas in a sample gas space.

1 shows an embodiment of a sensor arrangement according to the invention 110 for detecting particles of a measuring gas in a measuring gas space. The sensor arrangement 110 includes a sensor element 112 , as in 1 indicated by the dashed rectangle. The sensor element 112 can have at least one soot path 114 include. The sensor element 112 comprises at least a first electrode structure 116 and at least a second electrode structure 120 , The first electrode structure 116 includes a first supply line 118 and a second supply line 122 , The second electrode structure 120 can be a third supply line 119 and a fourth supply line 121 include. The sensor arrangement 110 further comprises a control unit 124 , The control unit 124 has at least one measuring device 126 on, with the measuring device 126 is set up by an attachment of the particles to the first electrode structure 116 conditional change of electrical properties of the sensor element 112 capture. For this purpose, in particular a measuring resistor 145 be used. The control unit 124 further comprises at least a first test device 128 , which is arranged, the first electrode structure 116 over the first supply line 118 to apply at least a first test signal and a response signal of the first electrode structure 116 over the first supply line 118 and from the response signal to a functional state of the first electrode structure 116 close. The control unit 124 can continue at least a second test device 130 which is arranged, the second electrode structure 120 to apply at least a second test signal and a response signal of the second electrode structure 116 and from the response signal to a functional state of the second electrode structure 120 close. The first test device 128 can have at least one load resistor 140 respectively. The load resistor may be configured, the first electrode structure 116 over the first supply line 118 switchable to act on the first test signal. The load resistance 140 can by means of a switch 142 with the first electrode structure 116 be connectable. Furthermore, the control unit can at least one operational amplifier 144 and the measuring resistor 145 include. The resistance 145 and the operational amplifier 144 may be configured to detect the voltage drop.

Furthermore, the control unit 124 at least one electrical energy source, in particular a current source and / or a voltage source 132 , and at least one processor or circuit, which has a control function and / or evaluation function of at least one with the sensor arrangement 110 , in particular with the sensor element 112 , Generate generated measurement signal and / or response signal. In particular, the measuring device 126 and the tester 128 each completely or even partially on a common Microcontoller 134 be formed, which may include the processor and / or the circuit.

By the addition of the particles, in particular the electrically conductive soot particles, can between the first electrode structure 116 and the second electrode structure 120 , electrically conductive Rußbrücken form, which is a current flow between the first electrode structure 116 and the second electrode structure 120 can enable. This situation is in the 1 through a first electrode structure 116 and the second electrode structure 120 connecting resistance 136 shown. Furthermore, the sensor element 112 a heating resistor 138 and a temperature measuring resistor 139 include. In particular, the heating resistor 138 be set up, the sensor element 112 , in particular the first electrode structure 116 and the second electrode structure 120 free from the particles, in particular the soot particles.

Also the first test device 128 can have at least one electrical energy source. In particular, the test device 128 the voltage source 132 respectively. The voltage source 132 In particular, it can be set up to generate a constant voltage. The test signal can be passed through the first test device 128 by switching on and off the load resistor ( 140 ) be generated. The first test device 128 may further comprise at least one detection device for detecting the response signal, in particular a voltage measuring device and / or a current measuring device. The control unit 124 , in particular the first test device 128 and / or the second test device 130 and / or the measuring device 126 , In particular, at least one DC / DC converter 143 respectively.

2 shows a flow chart of a method according to the invention for detecting particles of a sample gas in a sample gas space. It can be a sensor arrangement 110 used, which at least partially according to the sensor arrangement 1 equivalent. It may therefore depend on the description of the 1 referenced above.

In step 146 At least one measurement signal is detected, wherein by means of the measurement signal a caused by an attachment of the particles to the electrode structure change in electrical properties of the sensor element can be detected. Subsequently, at least one check of a functional state of the electrode structure is carried out. The review includes in step 148 a loading of the first electrode structure with a first test signal. It can be step 150 be performed, which comprises applying the second electrode structure with a second test signal. After step 148 a response signal to the first time-varying test signal can be detected, shown as step 152 , It can after step 152 to check whether a threshold is exceeded, represented as a step 154 , After step 150 a response signal to the second test signal can be detected, shown as step 156 , It can after step 156 to check whether a threshold is exceeded, represented as a step 158 ,

QUOTES INCLUDE IN THE DESCRIPTION

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

Cited patent literature

• DE 102005053120 A1 [0003]
• DE 10319664 A1 [0003]
• DE 102004046882 A1 [0003]
• DE 102006042362 A1 [0003]
• DE 10353860 A1 [0003]
• DE 10149333 A1 [0003]
• WO 2003/006976 A2 [0003]
• DE 102009028239 A1 [0004]
• DE 102009028283 A1 [0004]
• DE 2007046096 A1 [0004]
• US 2012/0119759 A1 [0004]

Claims (10)

Sensor arrangement (110) for detecting particles of a measurement gas in a measurement gas space, wherein the sensor arrangement (110) comprises: • at least one sensor element (112) having at least one first electrode structure (116) and at least one second electrode structure (120), wherein the first electrode structure (116) at least one first supply line (118) and at least one second supply line (122); • at least one control unit (124), wherein the control unit (124) comprises at least one measuring device (126); characterized in that the measuring device (126) is set up in order to change the electrical properties of the sensor element caused by an accumulation of the particles between the first electrode structure (116) and the second electrode structure (120) by measuring a voltage drop across at least one measuring resistor (145). to detect at the first electrode structure (116); and wherein the control unit (124) further comprises at least one first test device (128), wherein the first test device (128) is arranged to act on the first electrode structure (116) via the second supply line (122) with a first test signal and a first response signal the first electrode structure (116) via the first supply line (118) to detect. Sensor arrangement (110) according to the preceding claim, wherein the first test device (128) is arranged to switchably apply the first electrode structure (116) to a first test signal. Sensor arrangement (110) according to one of the preceding claims, wherein the first test device (128) has at least one load resistor (140), wherein the load resistor (140) is arranged, the first electrode structure (116) switchable via the second supply line (122) to apply the first test signal. Sensor arrangement (110) according to one of the preceding claims, wherein the measuring device (126) is adapted to detect the voltage drop across the measuring resistor (145) by means of at least one operational amplifier (144). Sensor arrangement (110) according to one of the preceding claims, wherein the control unit (124) further comprises at least one second test device (130), wherein the second test device (130) is adapted to apply a second test signal to the second electrode structure (120) and a second response signal of the second electrode structure (120) to detect. Sensor arrangement (110) according to the preceding claim, wherein the second electrode structure (120) is set up for at least one method selected from the group consisting of: detecting at least one measurement signal which is dependent on an attachment of the particles (114) between the first electrode structure ( 116) and the second electrode structure (120); a temperature measurement. Sensor arrangement (110) according to one of the two preceding claims, wherein the sensor element (112) further comprises at least one further device selected from the group consisting of: a heater (138), a temperature measuring device, wherein the second electrode structure (120) the further device in whole or in part. Method for detecting particles of a measuring gas in a measuring gas space, wherein a sensor arrangement (110) according to one of the preceding claims is used, the method comprising the following steps: a) detecting at least one measuring signal, wherein by means of the measuring signal a conditional by an attachment of the particles to the electrode structure change in electrical properties of the sensor element (112) can be detected; and b) carrying out at least one check of a functional state of at least one electrode structure selected from the group consisting of: the first electrode structure (116), the second electrode structure (120). Method according to the preceding claim, wherein step b) comprises the following steps: i. Applying a first test signal to the first electrode structure (116), detecting a response signal to the first test signal; ii. Evaluating the response signal and generating at least one information regarding a functional state of the first electrode structure (116). Method according to one of the two preceding claims, wherein step b) comprises the following steps: I. applying a second test signal to the second electrode structure (120); II. Detecting a response signal to the second test signal; III. Evaluating the response signal and generating at least one information regarding a functional state of the second electrode structure (120).

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