KR20180077077A - Device for detecting particles in a gas - Google Patents

Abstract

The present invention relates to a device (110) for detecting particles (114) in gas, and particularly exhaust gas in an internal combustion engine; and a method for detecting particles (114) in gas, and particularly exhaust gas in an internal combustion engine. The device (110) comprises: at least one measuring chamber (116) comprising at least one charging device (134), which electrostatically charges at least a part of particles (114) to generate charged particles (136), and capable of flowing by means of gas; at least one sensor device (122) detecting charged particles (136); and at least one heating device (162) designed to heat a partial volume (164) of at least one measuring chamber of the measuring chamber (116).

Description

≪ Desc / Clms Page number 1 > DEVICE FOR DETECTING PARTICLES IN A GAS &

The invention relates to a device for detecting particles in the gas, in particular in the exhaust gas of an internal combustion engine, and a method for detecting particles in the gas, in particular in the exhaust gas of an internal combustion engine.

The dust removal methods of gas have long been successful in the industry. The methods used herein are various and include, for example, filtration and electrostatic treatment. There is a growing demand for monitoring of particulate emissions in connection with steadily increasing emissions legislation.

Many methods and devices for detecting particles are known in the prior art. For example, the particles may be carbon black particles or dust particles. For example, the device may comprise a ceramic sensor element and a protective tube. The ceramic sensor element may comprise an electrode system designed to measure carbon black based on the electrical conductivity of the carbon black.

EP 2 659 257 B1 describes a facility for monitoring particles in a channel or space containing an aerosol. The apparatus includes an ejector, a gas supply configured to supply an ionized gas stream substantially free of particles to the ejector, and a gas supply configured to be tested by an inhalation action provided by the gas supply and the ejector to charge at least a portion of the particles of the test aerosol flow. And a test inflow device configured to supply the aerosol flow from the channel or space into the ejector. The apparatus also includes an ion trap for separating ions not attached to the particles from the ejector flow exiting the ejector. The ion trap extends at least partially into the ejector in the form of a trap wire.

Despite the many advantages of the methods and apparatuses for detecting particles known in the prior art, they still involve improvement possibilities. In known devices and methods, the charge of a relatively small number of particles is measured, which generally results in a very small measurement flow, thereby requiring a high insulation requirement for the sensor in relation to the life of the sensor. In addition, carbon black particles and / or other conductive particles and / or reversed conductive particles or ions may remain temporarily or permanently on the walls of the measurement chamber of the device. Also, condensation water after cold start can be given in the measurement chamber, which can make the operation time longer.

Therefore, an apparatus which deals with the technical challenges is preferable. Especially, even at very low concentrations, a representative, long-term stable detection of particle emissions and a long lifetime must be provided.

There is proposed a device for detecting particles in exhaust gas of a gas, in particular an internal combustion engine, and a method for detecting particles in a gas, in particular an exhaust gas of an internal combustion engine, at least substantially avoiding the aforementioned problems of known devices and methods .

In a first aspect of the present invention, an apparatus for detecting particles in a gas, in particular an exhaust gas of an internal combustion engine, is proposed. The apparatus comprises at least one measurement chamber which is capable of being perfused by a gas. The measurement chamber includes at least one charging device for electrostatically charging at least a portion of the particles to generate charged particles. The apparatus also includes at least one sensor element and at least one heating device for detecting charged particles. The heating device is designed to heat at least one measuring chamber portion volume of the measuring chamber.

"Internal combustion engine" in the present invention means any device capable of supporting or practicing the combustion process. In particular, the internal combustion engine may be an apparatus having at least one combustion chamber. In particular, the internal combustion engine may be a heat engine that converts chemical energy into mechanical energy by combustion of at least one fuel. An example is an engine, especially a diesel engine. Other types of internal combustion engines are also available by default.

 "Particles" in the context of the invention may, in the context of the invention, mean particles having a smaller size than the generally considered system, in particular the internal combustion engine or the exhaust gas system itself. Particularly, the particles may have a particle size or average particle size of less than 1 millimeter, typically less than 1 micrometer. The particles may be particles having an average particle size of, for example, 20 nanometers to 300 nanometers. The particles may basically be electrically insulating and / or electrically conductive particles such as, for example, carbon black particles or dust particles. The carbon black may be a black solid, especially containing at least carbon in general.

The term "gas" in the present invention can basically mean any fluid in which the particles freely move at a large distance from each other and evenly fill the space provided. The term "exhaust gas " in the present invention may mean, in particular, gaseous waste in the combustion process, which may also contain solid and / or liquid mixtures, for example in the form of particles and / or droplets.

Detection in the present invention may basically mean any process in which at least one measurement size, e.g., a physical and / or chemical measurement size, particularly an optical and / or electrical measurement size, is detected. "Detection of particles" can basically refer to any process for qualitative and / or quantitative detection of particles. Detection may involve the use of a detector. In particular, detection may involve the use of sensor elements of the device. In the present invention, a "sensor element" may basically mean any device designed to detect at least one measurement size, for example a physical and / or chemical measurement size, in particular an optical and / or electrical measurement size. The sensor element for detecting particles may basically mean any measuring device designed to qualitatively and / or quantitatively detect particles. The sensor element may in particular be designed to produce at least one sensor signal, in particular at least one electrical sensor signal, e.g. an analog and / or digital sensor signal. The sensor element may in particular be at least one particle sensor, for example a particle sensor based on resistance measurements. The sensor element may also be, for example, a particle counter, or it may be a detector that detects the density of the particle flow. As will be described in more detail below, basically any sensor principle can be used. For example, based on electrical measurement principles, such as sensor elements based on measurements of electrical resistance that can be influenced by particles, acoustic measurement principles, such as the measurement of the oscillation frequency of vibrating elements that can be affected by particles , Sensor elements based on optical measurement principles, such as light scattering by particles, in particular scattering of light, can be used. It is also possible to use techniques based on the above techniques and / or a combination of other techniques, and other techniques for detecting particles, such as techniques based on photoacoustic principles and / or laser induced incandescence.

As used herein, the term "measurement chamber" may refer to any chamber or any space designed to perform essentially the measurement and / or detection, especially those that detect particles in the gas. The measuring chamber may be made, for example, completely or partially from a rigid material, such as metal and / or plastic. The measuring chamber can basically have any cross-section, for example a rectangular cross-section. The measurement chamber may also be formed at least partially as a hollow body. The flow of the gases, in particular the exhaust gases, in the measuring chamber can be formed, for example, in laminar or turbulent flow, and can for example depend on the load conditions of the internal combustion engine. The measurement chamber may in particular comprise at least one detection zone. In the present invention, the detection region may basically mean any spatially defined region within the measurement chamber in which the detection of the particles by the detector can take place. For example, the detection region may be disposed at the center of the measurement chamber. Other embodiments are basically possible.

A "charging device" for electrostatically charging at least a portion of the particles in the present invention is essentially any device that applies charges to particles or portions of particles, e.g., negative and / or positive charges, . ≪ / RTI > Basically all the mechanisms known in the prior art for the charging of particles, such as photoelectric charging devices, charging devices using ionizing radiation, or electrostatic charging devices can be used. In particular, the charging device can be an electrostatic charging device that charges particles by means of one or more electrodes, for example by corona discharge and / or other types of electric discharges, in which case for example negative charges are transferred Or separated from the particles or portions thereof. In particular, a charging device can be designed to transfer a negative charge carrier to particles using an electrode.

The charging device for electrostatic charging includes at least one device for generating a corona discharge in particular in the exhaust gas. Corona discharge in the present invention basically refers to an electric discharge in an electrode in a non-conductive medium where a higher charge carrier concentration appears relative to the neutral state of the medium. In particular, the corona discharge may be a peak discharge, and the device for generating a corona discharge may comprise at least one electrode, for example an electrode with at least one electrode tip, preferably at least one discharge electrode and at least one counter electrode . The discharge electrode may in particular comprise at least one discharge tip. The counter electrode may especially be formed in a flat surface. For example, as a counter electrode, a flow pipe, which may be formed, for example, of metal and grounded or connected to electrical ground, may be used. For example, an insulated, planar counter electrode may be implemented. In particular, the nonconductive medium may be air and / or exhaust gas.

The charging device for electrostatic charging may in particular comprise at least two electrodes, for example at least one discharge electrode and at least one counter electrode. The discharge charging electrode may in particular comprise at least one electrode tip. Alternatively or additionally, other electrode types, especially rod electrodes with a small radius, e.g. hemispherical or spherical tips, are possible. For example, the counter electrode may be implemented as an insulated, planar counter electrode. The discharge electrode, in particular the electrode tip, can protrude into the measurement chamber. Other embodiments are basically possible. The charging device for electrostatic charging can be electrically insulated, especially for the flow pipe, in particular for the discharge electrode. Thus, the charging device for electrostatic charging may comprise at least one insulator, in particular electrically insulated for the flow pipe.

In the present invention, the term "heating device" may refer to any device that is designed to supply essentially any heat and / or thermal energy to any volume and / or to warm the volume and / or the device. In particular, the heating device can be designed to heat the volume of the measurement chamber. Further, the heating device can be designed to generate heat flow. The expression heat flow basically represents heat transfer. Generally, heat transfer takes place toward a place with a lower temperature due to the temperature difference. For example, the heat transfer may be from one location in the measurement chamber to another location in the measurement chamber.

As mentioned above, the heating device is designed to heat at least the volume of the measuring chamber portion of the measuring chamber. The expression "measurement chamber partial volume" basically represents a portion of the volume of the measurement chamber relative to the total volume of the measurement chamber. In particular, the sensor element has an electrical measurement principle, and the heating device can be designed to permanently or temporarily, in particular, occasionally, heat the measuring chamber partial volume. In particular, the heating device may be designed to heat the volume of the measurement chamber at a point in time that a leakage current, which may affect the electrical measurement signal, for example, may be formed through an insulator between the electrodes. In particular, the counter electrode of the charging device as part of the flow pipe can be electrically insulated. The counter electrode may also be electrically insulated to the sensor housing of the sensor element. In particular, the insulation resistance can have an electrical resistance of 100 M? To 100 T? Over the lifetime of the device. In particular, the heating device can be designed to heat the surfaces of the measuring chamber, in particular the critical surfaces of the measuring chamber. The expression "critical surface" refers to the surfaces in the interior space of a measurement chamber designed to detect particles in the gas, in particular the surfaces which are part of the sensor element. For example, the sensor element may be an optical sensor element and the heating device may be designed to heat at least one optical window and / or at least one optical mirror. Other embodiments are basically possible. The heating device may also be designed to heat the periphery of the charging device.

The heating device may at least partially, i.e. completely or partially, protrude into the measurement chamber. The heating device may also be disposed at least partially within the measurement chamber. In particular, the heating device may be formed in a self-supporting manner. The expression "self-sustaining" refers to the characterization of any element that will endure without additional external elements for load acceptance in the context of the present invention. The heating device can be fixed to the wall of the measurement chamber, for example, through the end of the heating device and can protrude into the measurement chamber. The heating device may also be guided through the opening of the measurement chamber wall. A portion of the heating device may protrude into the measurement chamber and another portion of the heating device may be outside the measurement chamber. Other embodiments are basically possible.

The heating device may be arranged in the measuring chamber so as to extend parallel to the longitudinal axis of the measuring chamber. The expression "longitudinal axis" basically represents the axis of any element corresponding to the direction of the widest width of the element. In particular, the heating device includes a heating device portion disposed in the measurement chamber. The heating device portion may have a heating device part length corresponding to at least 40%, preferably at least 50%, preferably at least 60% and particularly preferably at least 70% of the measuring chamber length of the measuring chamber. The heating device may be arranged such that surfaces or areas which are part of the sensor element, in particular surfaces which contribute to signal formation, can be burnt in the measuring chamber. In particular, the heating device can be designed to burn surfaces which are part of the sensor element, in particular to reduce or eliminate condensate on the surfaces. In particular, the surfaces or regions may comprise insulators separating electrically conductive regions having different dislocations from one another. The sensor element may also be an optical sensor element, and the surfaces or regions may comprise optically active surfaces, such as windows and / or mirrors. Depending on the embodiment of the measuring chamber and / or the sensor element, the volume of the measuring chamber may be in the region of the measuring chamber, for example between 5% and 60%, preferably between 10% and 50% of the measuring chamber, % To 30% of the total volume of the measuring chamber, or can occupy most of the measuring chamber, for example 70% to 95%, preferably 80% to 90% of the measuring chamber. In addition, the volume of the measurement chamber part can occupy 100% of the volume of the measurement chamber.

The heating device may also be disposed at least partially on the heating device support element. The expression "support element" refers basically to any element designed to mechanically support, e.g. The expression "holding" means that the support element can be formed to be separate from other elements and the other element can be placed on the support element and held in the apparatus, and / or the other element can be completely or partially incorporated And the like. For example, the supporting element may be formed as a separate member and independently of other elements. Alternatively, the support element may comprise, for example, as an integral component, completely or partially other elements.

The heater support element may be made at least partially of an electrically insulating material. The electrically insulating material may be any material suitable for at least substantially preventing current flow, basically in the context of the present invention, for example a material having a specific conductivity of at least 10 ⁸ Ωm, in particular at least 10 ¹⁰ Ωm. The electrical insulation of the heater support element can also be achieved at high temperatures, such as 400 [deg.] C, which may appear in the exhaust gas. The electrically insulating material may in particular comprise a ceramic material, for example aluminum oxide. Other materials are basically possible. The heater support element may be at least partially formed as a pipe, in particular a cylindrical pipe. The pipe may extend along the longitudinal axis of the measurement chamber. The heating device may include at least two heating device supply lines. For example, the heating device feed lines may be mounted at least partially within the heating device support element and / or at least partially outside the heating device support element. The heater support element may be designed to electrically isolate the heater supply lines, in particular by means of an intermediate wall, to the ion trap electrode of the ion trap apparatus described below.

The heating device may also include at least one heating resistor. The heating device may in particular comprise an electrically conductive material. For example, the heating device may comprise at least one metallic material. In particular, the metal material may include at least one element selected from the group consisting of platinum, rhodium, and palladium. Other elements are basically possible. The heating device may also comprise at least one metal alloy as the electrically conductive material. The metal alloy may include at least one element selected from the group consisting of platinum, rhodium, and palladium. Other elements are basically possible. Non-noble metal compounds, such as nickel, copper, chromium, aluminum and iron, are also possible, especially for thermally conductive alloys.

The heating element may have a long and long shape. Other embodiments are basically possible. In particular, the heating device may include at least one heating coil. The expression "coil" refers to a spiral or cylindrical spiral wound around an outer surface of a hypothetical cylinder at least at a substantially constant pitch. The heating coil may be arranged, for example, on the heating device support element. In particular, the heater support element can be disposed within the heating coil, and the heating coil at least partially surrounds the heater support element.

The heating device may also be arranged on at least one measuring chamber wall of the measuring chamber. For example, the heating device may be arranged in a self-supporting configuration, which may be a small distance from the surfaces which are part of the sensor element, in particular from surfaces which contribute to signal formation, in particular from critical surfaces, Preferably between 0.75 mm and 2 mm, and particularly preferably between 1 mm. The heating device can be arranged to burn critical surfaces with particularly low heating power and to reduce or eliminate condensate on critical surfaces. The heating device may also be mounted on at least one ceramic carrier directly on the measurement chamber wall of the measurement chamber. Alternatively or additionally, the heating device may be mounted on the insulating surface of the measuring chamber wall. Other embodiments are basically possible.

The measurement chamber may be in fluid communication with at least one flow pipe that is permeable to gas. A "flow pipe" in the present invention can basically mean any hollow body that can be perfused by a fluid. The hollow body may be a particularly long hollow body. The flow pipe can be made, for example, completely or partially from a rigid material, or completely or partially from a flexible material, for example metal and / or ceramic. The flow pipe may basically have any cross section, for example a round, oval or polygonal cross section. The flow pipe can be used, for example, in an exhaust gas system of an internal combustion engine. The flow of the exhaust gas in the flow pipe may be formed, for example, by laminar or turbulent flow, and may for example be dependent on the load state of the internal combustion engine.

In particular, the apparatus may also include at least one gas exchange device for guiding the gas from the outer periphery of the measurement chamber into the measurement chamber and from the measurement chamber to the outer periphery. The expression "gas exchange device" essentially refers to any device designed to spatially distribute any gas between at least two compartments. In particular, the gas exchange device can be connected to the measurement chamber by at least one inlet opening and by at least one outlet opening. The inlet opening can be designed to carry gas from the outside periphery of the measurement chamber into the measurement chamber. Further, the discharge opening can be designed to carry gas from the interior of the measurement chamber, in particular to the outer periphery of the measurement chamber. For example, the measuring chamber may be fluidly connected to the flow pipe by a gas exchange device as described above or as further described below.

The measurement chamber may also include at least one compression device for compression of charged particles. The expression "compression device" means within the scope of the invention essentially any device designed to compress any particles in the gas into a second volume within a first volume, said second volume being smaller than said first volume . The particles can be bundled by the compression device. Bundling generally refers to deflection or collimating of the flowing particles, and the flight path of the particles is combined to increase the particle concentration in volume. The charged particles can be bundled by a compression device, in particular into one path of flow, thereby being held in the center of the flow. Thereby, particle adhesion on the perfused body, in particular on the boundary walls of the measurement chamber, can be prevented. The compression device may be disposed at least partially within the volume of the measurement chamber. The compression device may comprise at least two protrusions, for example. The two protrusions can in particular be arranged on the opposing measuring chamber walls of the measuring chamber and protrude into the measuring chamber. The two protrusions can form a channel through which the charged particles flow. The channel can be designed to bundle, in particular, charged particles in a path of flow through the channel and thereby keep it in the center of the flow. For example, the channel may be arranged so that the tip of the charging device points in the channel. Other embodiments are possible. For example, compression and / or bundling of particles may be supported by an externally applied electric field.

The measuring device may also include an ion trap device. The expression "ion trap device" refers to any device designed to deflect and / or maintain and / or store charged particles, especially charged atoms or molecules, by electric and / or magnetic fields in the context of the present invention. Certain amounts of ions may be intentionally maintained depending on the type and / or intensity of the electric field and / or the magnetic field. The storage of the ions can be done in particular in vacuum without contact with the surface. For example, time-varying electromagnetic fields can be used to hold ions. In addition, a constant magnetic field can be used depending on a constant electric field and time according to time. Other embodiments are possible. The ion trap device may include at least one ion trap electrode. In particular, the ion trap electrode can be designed to at least substantially separate free ions from charged particles. The ion trap electrode is particularly long and long in shape. Further, the ion trap electrode may be arranged to face the charging device. Further, the ion trap electrode may be arranged so that the tip of the ion trap electrode points to the channel of the compression apparatus.

The ion trap electrode may comprise at least one insulating device. In particular, the ion trap electrode may be partially contained within the insulating device and partially protruding from the insulating device. For example, the isolator may include a cylindrical pipe and the ion trap electrode may be at least partially received within the cylindrical pipe. The cylindrical pipe may extend along the longitudinal axis of the measurement chamber. The cylindrical pipe may also protrude from the measurement chamber wall into the measurement chamber. The portion of the ion trap electrode protruding from the insulating device may form an arch, in particular the tip of the ion trap electrode facing the charging device and / or the compression device. The insulating device can also be designed as a supporting element for the heating device. For example, the heater support element may be the same as the isolation device of the ion trap electrode as described above or as described below. Other embodiments are possible.

In another aspect of the present invention, a method for detecting particles in exhaust gas of a gas, particularly an internal combustion engine, is proposed. The method steps may be performed in the order described above, or in other orders. Also, two, many, or all of the above-described method steps may overlap in time or simultaneously. Also, one, many, or all of the above-described method steps may be performed once, repeatedly, or permanently. The method may also include one or more additional methods not described above. The above description of the device can basically be referred to for other details of the method, since the method can be carried out in particular using the proposed device.

A method for detecting particles in a gas

a) providing gas in at least one measurement chamber;

b) electrostatically charging at least a portion of the particles in the gas to generate charged particles; And

c) detecting charged particles by at least one sensor element, in particular in the detection area,

During the method, at least one of the measuring chamber partial volumes is heated by at least one heating device.

The proposed apparatus and method have a number of advantages over known apparatuses and methods. Known devices and methods generally can assume that the charge of a relatively small number of particles is measured, which generally results in a very small measurement flow and thus a high insulation requirement for the sensor with respect to the life of the sensor . In addition, carbon black particles and / or other conductive particles and / or reversed conductive particles or ions may remain temporarily or permanently on the walls of the measurement chamber of the device. Also, condensation water after a cold start can be given in the measurement chamber, which can make the operation time longer.

The aging resistance of the device can be improved by the device according to the present invention. Particularly, it is possible to improve the aging resistance of the device by the heating device and to realize the device as a solid exhaust gas sensor in vehicles having an internal combustion engine. Also, sensor signal availability is improved. The heating device can be obtained at a minimum cost for the additional member. In certain operating phases, the measurement chamber may be heated to separate carbon black and other particles from the inner measurement chamber walls, for example, by a thermal retainer or by removal by burning. The heating device can also be used to quickly evaporate water and / or condensate in a given measurement chamber, typically after a cold start, thereby further accelerating the measurement atmosphere.

For example, a conventional ceramic insulator for an ion trap electrode can be used as a supporting element for a heating apparatus. In particular, the insulating element with the heating device can preferably be mounted as centrally as possible within the measuring chamber, in order to achieve the possible uniform heating of the measuring chamber walls. Mounting to heat partial areas of the measurement chamber may also be desirable, which prevents more undesirable attachment of the particles.

In particular, by means of the heating device the relevant areas of the measuring chamber walls can be heated as quickly and completely as possible. Also possible is that the possible sinks in the measuring chamber, in which water and / or condensate can collect, can be easily heated. The heater supply lines may each be mounted inside the support element and / or outside the support element. The ion trap electrode and the heating device supply lines can be electrically insulated from each other. For example, a cylindrical, cylindrical, pipe may include an intermediate wall therein to separate heating device supply lines from each other. Further, the heating device can be realized by the supporting element without resorting to the insulating element of the ion trap. In this case, for example, a ceramic pipe or rod may be used. The heating element may also be mounted near one or more inner measuring chamber walls. A self-supporting structure of the heating device using supply lines without supporting elements is also possible. In this case, the insulation may only be required in small areas, especially at the locations where the supply lines are guided into the measurement chambers. The gas flow used for charging the particles can also be heated.

The heating device may be embodied as a heating coil made of, for example, a thermally conductive alloy or a resistance alloy having resistance to oxidation in oxygen in the atmosphere and also resistant to temperatures up to, for example, 800 占 폚. Alternatively, an implementation with platinum mounted on an Al ₂ O ₃ ceramic by, for example, a thick film technique can be made.

Other optional details and features of the invention are set forth in the following description of the preferred embodiments, which are schematically illustrated in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross-sectional view of one embodiment of an apparatus according to the present invention in cross section parallel to the longitudinal axis of the apparatus;
2 is a cross-sectional view of another embodiment of the device according to the invention in cross section parallel to the longitudinal axis of the device.

1 illustrates an embodiment of an apparatus 110 according to the present invention for detecting particles 114 in a gas, particularly an exhaust of an internal combustion engine, in a cross-section parallel to the longitudinal axis 112 of the apparatus 110 Sectional view is shown.

Apparatus 110 includes a measurement chamber 116 that is permeable to gas. The measurement chamber 116 has, for example, a rectangular cross section. The measurement chamber 116 may include a plurality of measurement chamber walls 118. In addition, the measurement chamber 116 may include at least one detection region 120 in which the detection of the particles 114 may be effected by the sensor element 122. The apparatus 110 also includes at least one gas exchange device (not shown) for guiding the gas from the outer periphery 126 of the measurement chamber 116 into the measurement chamber 116 and from the measurement chamber 116 to the outer periphery 126 124). In particular, the gas exchange device 124 may be connected to the measurement chamber 116 by at least one inlet opening 128 and by at least one outlet opening 130. In particular, the device 110 may be in fluid communication with the flow pipe 132 by a gas exchange device 124. The flow pipe 132 may be used, for example, in an exhaust gas system of an internal combustion engine.

The measurement chamber 116 includes at least one charging device 134 for electrostatically charging at least a portion of the particles 114 to generate charged particles 136. The charging device 134 for electrostatically charging can in particular comprise at least one device 138 for generating a corona discharge in the exhaust gas. The apparatus 138 for generating a corona discharge includes at least one electrode 140, e.g., a discharge electrode 144 having at least one electrode tip 142, in particular. The discharge electrode 144, in particular the electrode tip 142, can be projected into the measurement chamber 116.

In addition, the device 110 may include at least one ion trap device 146. The ion trap device 146 may be designed to deflect and / or maintain and / or store charged particles, particularly charged atoms or molecules, by electric and / or magnetic fields. The ion trap device 146 may include at least one ion trap electrode 148. The ion trap electrode 148 may have a particularly long shape in length. The ion trap electrode 148 may include at least one isolation device 150. In particular, the ion trap electrode 148 may be partially contained within the insulating device 150 and partially protruding from the insulating device 150. For example, the isolation device 150 may include a cylindrical pipe 152 and the ion trap electrode 148 may be at least partially received within the cylindrical pipe 152. The cylindrical pipe 152 may extend along the longitudinal axis 112 of the measurement chamber 116. The cylindrical pipe 152 may also protrude from the measurement chamber wall 154 into the measurement chamber 116. A portion 156 of the ion trap electrode 148 protruding from the isolation device 150 may form an arch 158 such that the tip 160 of the ion trap electrode 148 faces the charging device 134 .

The apparatus 110 also includes at least one heating device 162 designed to heat at least one measurement chamber portion volume 164 of the measurement chamber 116. The heating device 110 may protrude at least partially, i.e. completely or partially into the measurement chamber 116. The heating device 110 may also be disposed at least partially within the measurement chamber 116. In particular, the heating device 110 may be formed in a self-supporting manner. The heating device 162 can be fixed to the measurement chamber wall 154 of the measurement chamber 116 and protrude into the measurement chamber 116. The heating device 162 may also be guided through the opening 166 of the measurement chamber wall 154. A portion 168 of the heating device 162 may protrude into the measurement chamber 116 and another portion 170 of the heating device 162 may be disposed outside the measurement chamber 116.

The heating device 162 may be disposed within the measurement chamber 116 to extend parallel to the longitudinal axis 112 of the measurement chamber 116. In particular, the heating device 162 may include at least one heating coil 172. The heater 162 may be disposed at least partially on the heater support 174. The heater support element 174 may be identical to the isolation device 150 of the ion trap electrode 148. The heating device support element 174 and the heating device 162 may be attached as centrally as possible within the measurement chamber 116 to achieve possible uniform heating of all associated internal measurement chamber walls 118. In particular, the heater support element 174 may include a heater portion 171 disposed within the measurement chamber 116. The heater section 171 may include a heater section length L _H corresponding to at least 80% of the measurement chamber length L _M of the measurement chamber 116. The heater 162 may extend over the total length L _T of the heater support element 174. Alternatively, the heating device 162 may be configured to act particularly strongly in the partial regions of the critical measurement chamber 116, particularly in signal formation. This may include, for example, surfaces of insulators between electrodes that are at different electric potentials. The device 110 may also include at least one compression device 176 for compressing the charged particles 136. The compression device 176 may be disposed at least partially within the measurement chamber volume 164. The compression device 176 includes at least two protrusions 178, for example. The two protrusions 178 can be disposed on the opposing measurement chamber walls 180 of the measurement chamber 116 and can protrude into the measurement chamber 116. The two protrusions 178 form a channel 182 through which the charged particles 136 flow. The channel 182 can be designed to specifically bundle the charged particles 136 in one path of the flow through the channel 182 to keep it in the center of the flow. For example, the channel 182 may be arranged so that the tip 142 of the charging device 134 points into the channel 182. The sensor element 122 may be designed to determine the charge of the charged particles 114 in such a way that a current through the discharge opening 130 is detected. The current through the discharge opening can be determined in particular by the electrical device 186. The electrical device 186 includes a high voltage source 188 that is coupled to the charging device 134 to provide a high electrical voltage to the charging device 134 in particular. The high voltage source 188 may be electrically isolated by the isolation element 190 and the additional isolation element 192. The electrode 140 of the charging device 134 has an electric potential corresponding to the electric potential of the walls 194 of the charging device 134. [ The electrical device 186 may also include an electrometer 196 that may form a galvanic contact 198 with the wall 200 of the housing 202 of the electrical device 186. [ The high voltage source 188 may be electrically connected to the charging device 134 and the electrometer 196. The electrometer 196 may also be electrically connected to the wall 200 of the housing 202 of the electrical device 186. Thus, the electrometer 196 may be designed to determine the charge of the charged particles 114 in such a manner that a current through the discharge opening 130 is detected. Other embodiments are basically possible.

2 shows an alternative embodiment of an apparatus 110 according to the present invention for detecting particles 114 in a gas, particularly an exhaust of an internal combustion engine, in a cross-section parallel to the longitudinal axis 112 of the apparatus 110 Sectional view is shown. Device 110 generally corresponds to device 110 according to FIG. 1, so that the description of FIG. 1 can be generally referred to.

In the apparatus 110 according to FIG. 2, the heating device 162 can be mounted such that the partial area 184 of the measurement chamber 116 is heated. Partial region 184 may comprise a channel 182 formed by compression device 176 in particular. The heater section 171 includes a heater section length L _H corresponding to at most 45% of the measurement chamber length L _M of the measurement chamber 116. The heater 162 may extend up to 55% of the length L _T of the heater support 174.

110 device
114 particles
116 measuring chamber
122 sensor element
134 charging device
136 charged particles
146 Ion trap device
150 Isolation device
162 Heating device
164 Measurement chamber part volume
171 Heating device part
172 Heating coil
174 Heating device support element
L _H Heating device part length
L _M Measurement chamber length

Claims (12)

An apparatus (110) for detecting particles (114) in a gas, particularly an exhaust of an internal combustion engine, the apparatus
- at least one measurement chamber (116) which is capable of being perfused by the gas, wherein the at least one measuring chamber (116) is capable of being perfused by gas, characterized in that it comprises at least one charging device (134) for electrostatically charging at least a part of the particles );
At least one sensor element (122) for detecting the charged particles (136); And
- at least one heating device (162) designed to heat at least one measuring chamber portion volume (164) of the measuring chamber (116). The apparatus of claim 1, wherein the heating device (162) is formed in a self-supporting manner. The apparatus according to any one of the preceding claims, wherein the heating device (162) projects at least partially into the measurement chamber (116). A device according to any one of claims 1 to 3, wherein the heating device (162) is disposed at least partially within the measurement chamber (116). 5. The apparatus according to any one of claims 1 to 4, wherein the heating device (162) is disposed within the measurement chamber (116) to extend parallel to the longitudinal axis (112) of the measurement chamber (162) An apparatus for detecting particles in a gas. 6. The apparatus according to any one of claims 1 to 5, wherein the heating device (162) comprises a heating device part (168) disposed in the measuring chamber (116) (L _H ) corresponding to at least 40% of the measurement chamber length (L _M ) of the heating chamber (116). 7. The apparatus according to any one of claims 1 to 6, wherein the heating device (162) is disposed at least partially on a heater support element (174). 8. An apparatus according to any one of claims 1 to 7, wherein the heating device (162) comprises at least one heating coil (172). 9. The apparatus according to any one of the preceding claims, wherein the measuring chamber (116) further comprises at least one ion trap device (146), the ion trap device (146) comprising at least one insulating device , And wherein the insulating device (150) is also designed as a support element (174) for the heating device (162). 10. A device according to any one of claims 1 to 9, wherein the heating device (162) is arranged on at least one measurement chamber wall (118) of the measurement chamber (116) . 11. An apparatus according to any one of claims 1 to 10, wherein the heating device (162) is designed to heat the periphery of the charging device (134). A method for detecting particles (114) in a gas, in particular an exhaust gas of an internal combustion engine,
a) providing gas in at least one measurement chamber (116);
b) electrostatically charging at least a portion of the particles (114) in the gas to generate charged particles (136); And
and c) detecting the charged particles (136) by at least one sensor element (122), during which the at least one measuring chamber partial volume (164) is transferred to the at least one heating device ≪ / RTI > wherein the gas is heated by a gas.

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