Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N15/06—Investigating concentration of particle suspensions
  • G01N15/0656—Investigating concentration of particle suspensions using electric, e.g. electrostatic methods or magnetic methods
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/02—Circuit arrangements for generating control signals
  • F02D41/14—Introducing closed-loop corrections
  • F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
  • F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
  • F02D41/1466—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being a soot concentration or content
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N25/00—Investigating or analyzing materials by the use of thermal means
  • G01N25/72—Investigating presence of flaws
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
  • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
  • G01N27/043—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a granular material
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
  • G01N2015/0042—Investigating dispersion of solids
  • G01N2015/0046—Investigating dispersion of solids in gas, e.g. smoke

Definitions

• Sensor in particular soot sensor, and method for producing a sensor, in particular a soot sensor
• the invention relates to a sensor for detecting electrically conductive and / or polarizable particles, in particular a soot sensor comprising a substrate, an electrode layer formed on the substrate with at least two spatially separated and interdigitated electrodes, wherein on the side facing away from the substrate of the electrode layer at least a cover layer is formed. Furthermore, the invention relates to a method for producing a sensor according to the invention, in particular a soot sensor.
• WO 2006/111386 A1 describes an exemplary electrode structure or an exemplary sensor. Between the electrodes, the drop in electrical resistance is measured by the increasing soot occupancy. By forming a heating element on or in the soot sensor, the sensor can be regenerated after heavy soot occupancy.
• the interdigitated electrodes should have the smallest possible distance from each other.
• such a small distance is produced by isolating the platinum electrodes by laser ablation of the platinum layer applied over the whole area and thus allowing electrode spacings of less than 50 ⁇ m to be realized.
• the invention is based on the object to provide a further developed sensor, in particular a soot sensor, which has an increased sensitivity. Furthermore, it is an object of the present invention
• this object is achieved with regard to the sensor by the features of claim 1.
• the object is achieved by the features of claim 9.
• the invention is based on the idea of specifying a sensor for detecting electrically conductive and / or polarisable particles, in particular a soot sensor, wherein the sensor comprises a substrate, an electrode layer formed on the substrate with at least two electrodes spatially separated from one another and engaging one another at least one covering layer is formed on the side of the electrode layer facing away from the substrate.
• a plurality of openings are formed in the cover layer, which at least partially expose a surface of an electrode, in particular of the at least two electrodes. It can be seen that the sensitivity of the sensor is increased when the covering layer, which covers large parts of the sensor, in particular large parts of the electrode layer, is suitably structured, in particular laser-structured.
• the substrate is preferably made of alumina (Al 2 O 3) and / or zirconia (ZrO 2 ) and / or zirconia (ZrO 2 ) with insulation and / or other oxide ceramics.
• the substrate has a thickness of 0.5-1.0 mm.
• an electrode layer is formed on one side of the substrate.
• This electrode layer comprises at least two electrodes, which are spatially separated from each other and intermesh.
• Such electrodes may, for example, be comb electrodes and / or interdigitating electrodes.
• the at least two electrodes do not touch. Instead, electrode sections of a first electrode are arranged in recesses of electrode sections of the second electrode, but without touching each other.
• the thickness of the electrode layer is preferably 0.5 to 20.0 ⁇ m.
• the covering layer can be formed, for example, from aluminum oxide (Al 2 O 3) and / or silicon dioxide (SiO 2) and / or glass.
• the cover layer preferably has a thickness of 0.5 ⁇ - 20.0 ⁇ on.
• a plurality of openings are formed, which are preferably slot-shaped.
• slot-shaped openings are to be understood such openings whose length is greater than the width.
• the slot-shaped openings are formed parallel to each other.
• the slot-shaped openings form a uniform pattern. That is, a plurality of rows of slot-shaped openings are arranged side by side, wherein the distances of the rows preferably each have the same amount.
• the slot width of the openings is preferably between 1.0 ⁇ - 50.0 ⁇ .
• the electrodes preferably have a plurality of elongated finger sections.
• the finger sections of the at least two electrodes are preferably arranged parallel to one another.
• the longitudinal extension of the slot-shaped openings may be formed parallel and / or perpendicular to the longitudinal extent of the finger portions, wherein the longitudinal extent of all slot-shaped openings are preferably formed parallel to each other.
• the cover layer is formed such that all the longitudinal extensions of the slot-shaped openings are formed either parallel or perpendicular to the longitudinal extent of the finger portions.
• the slot-shaped openings are in the
• Filaments or soot filaments grow from a negatively poled electrode to a positively poled electrode, preferably in the direction of gas flow.
• a sensor is arranged in a gas flow such that the gas flow direction is perpendicular to the longitudinal extension of the finger sections.
• the sections or remaining sections of the covering layer formed between the slot-shaped openings mechanically stabilize the described carbon black filaments. This leads to a preferred filament formation and thus to an increased sensitivity.
• the filaments in particular the soot filaments, can be used as chains
• contiguous particles in particular as chains of contiguous soot particles are called.
• filaments in particular soot filaments between adjacent electrodes, in particular between adjacent comb electrodes, reduces the electrical resistance as long as the filament contacts both electrodes.
• the sensitivity of the sensor is determined by the formation of the (soot) filaments.
• Finger portions may grow carbon black filaments along the remaining portions of the capping layer directly between the at least two electrodes.
• the openings in particular the slot-shaped openings, can at least partially expose the side surfaces of the finger sections and / or at least partially expose the top side of the finger sections.
• the exposed surface of at least one electrode is a portion of the top and / or side surface of the electrode.
• the lateral surfaces of the finger sections are to be understood as meaning the (substantially) surfaces of the electrodes formed perpendicular to the substrate or perpendicular to the covering layer.
• the side surfaces are (substantially) formed parallel to each other.
• the upper side of the finger sections are to be understood as meaning the sides pointing in the direction of the cover layer. At least in one
• the tops of the finger portions preferably completely, covered with the cover layer.
• the openings in particular slot-shaped openings, can at least partially expose the edge regions of the upper side of the finger sections.
• the edge regions of the upper side are to be understood as the regions of the upper side that contact the side surfaces of the upper side
• the surfaces of the exposed electrode sections may be coated at least in sections with glass fibers and / or with particles, in particular with aluminum oxide particles (Al 2 O 3) and / or with silicon dioxide particles (SiO 2).
• Another aspect of the invention relates to a method for producing a sensor according to the invention, in particular a soot sensor according to the invention.
• the method according to the invention is characterized by the following method steps
• Substrate c) applying a cover layer to the electrode layer, d) introducing, in particular slot-shaped, openings in the
• step d i. when introducing, in particular slit-shaped, openings in particular an ultra-short pulse laser is used.
• the ultra-short pulse laser is in particular a picosecond or
• Femtosecond laser With the aid of such an ultra-short pulse laser, it is possible to introduce slit-shaped openings with line widths of 1.0 to 50.0 ⁇ in the cover layer.
• step b) When forming an electrode layer, it is initially possible that, in step b), a planar electrode layer is first applied to the substrate and the electrode layer is subsequently patterned. A flat
• Electrode layer for example, by means of a deposition method, such. As screen printing and / or sputtering and / or thermal evaporation, are applied. The subsequent structuring of the electrode layer can
• the electrode layer by screen printing.
• metal pastes can first be applied by screen printing to form a later electrode structure.
• The, in particular ceramic, cover layer can be applied by screen printing and / or thermal vapor deposition and / or by ADM method (Aerosol Deposition Method). After applying the cover layer takes place According to the invention, the introduction of openings, in particular slot-shaped openings, by means of ultra-short pulse laser.
• the cover layer with a plurality of, in particular slot-shaped, openings is particularly preferably a laser-structured one
• Another subsidiary aspect of the invention relates to the use of a sensor according to the invention for the detection of electrically conductive and / or polarisable particles, in particular for the detection of soot particles.
• the invention relates to the use of a sensor according to the invention in an exhaust system, in particular in an exhaust system
• the sensor according to the invention is preferably arranged in the exhaust pipe such that the gas flow direction is aligned perpendicular to the longitudinal extensions of the finger portions of the electrodes.
• the (soot) filaments described above are in particular formed by a negatively poled electrode in the direction of the positively poled electrode in the gas flow direction.
• the portions of the cover layer, which are formed between the particular slot-shaped openings stabilize the (soot) filaments mechanically. Because of this, the preferential (soot) filament formation occurs. This requires an increased
• the senor according to the application or arrangement according to the invention in the exhaust pipe is designed such that the longitudinal extent of the slot-shaped openings are formed perpendicular to the longitudinal extent of the finger portions.
• the (soot) filaments may grow along the remaining covering layer portions directly between the at least two electrodes.
• the remaining cover layer sections may also be referred to as alumina (Al 2 O 3) bridges, as long as the cover layer is made of aluminum oxide.
• the described (soot) filaments preferably form along the edges and / or comb-like bridges of the exposed cover layer. Furthermore The (soot) filaments form in the "slipstream" or in the flow dead zone of local topology peaks of the covering layer.
• FIGS. 1a-6b show various stages and steps of the method for producing a sensor according to the invention, the method steps according to FIGS. 6a and 6b being alternatives to the method steps 5a and 5b;
• Fig. 8 shows a sensor according to the invention in the use state.
• FIGS. Representations of the sensor according to the invention in the respective process step shown in a plan view. Cross-sections through the sensor according to the respective process state or process step are shown in FIGS. It should be noted that the representations of the cross sections are not to scale, but that the applied layers are drawn greatly enlarged in the direction of the perpendicular to the surface of the substrate.
• the substrate 20 is shown.
• the substrate 20 may be made of alumina (Al 2 O 3) and / or zirconia (ZrO 2 ) and / or zirconia (ZrO 2 ) with isolation.
• the apparent in Fig. Lb thickness Dl can be 0.5 - 1.0 mm.
• a planar electrode layer 30 is first applied to the side 21 of the substrate 20.
• the electrode layer 30 is a platinum layer. This layer can be applied by means of a screen printing process and / or by means of a sputtering process and / or by means of a chemical vapor deposition process.
• the thickness D2 of the electrode layer 30 can have 0.5 to 20.0 ⁇ m.
• two electrodes namely a first electrode 31 and a second electrode 32 are generated by means of laser ablation.
• the two electrodes 31 and 32 are formed.
• the first electrode 31 has two finger portions 33.
• the second electrode has two finger portions 33.
• the 32 has three finger portions 34.
• the two electrodes 31 and 32 engage each other. In this case, the finger portions 33 and 34 of the electrodes 31 and 32 do not touch.
• the finger portions 33 and 34 of the two electrodes 31 and 32 are formed substantially parallel to each other.
• Finger sections 33 and 34 are preferably formed distances of 1.0 - 50.0 ⁇ . In particular, the distances A between the finger sections
• the electrodes 31 and 32 may also be referred to as
• Interdigit Schlierende electrodes are called.
• Electrode layer 30, a cover layer 40 is applied.
• the cover layer 40 may consist of aluminum oxide (Al 2 O 3) and / or silicon dioxide (SiO 2) and / or glass.
• the cover layer 40 is, for example, by means of a
• the cover layer 40 is applied to the electrode layer 30 in such a way that both the top sides 35 of the electrodes 31 and 32 and the side face 36 of the electrodes 31 and 32 (see FIGS. 3 a and 3 b) are coated with the cover layer 40.
• the cover layer 40 may consist of several superposed sections. Namely from a first section 41 and a second section 42. The two sections 41 and 42 arise from the fact that a uniform thickness D3 of the cover layer 40 is applied.
• the thickness D3 of the portion 42 applied on the side 21 of the substrate 20 is equal to the thickness D3 of the first portion 41 applied to the top 35 of the electrodes 31 and 32.
• the thickness D3 of the portion 42 applied on the side 21 of the substrate 20 is equal to the thickness D3 of the first portion 41 applied to the top 35 of the electrodes 31 and 32.
• Cover layer 40 is preferably 0.5 to 20.0 ⁇ . Because of the same layer thickness D3, protrusions 43 of the cover layer 40 are formed.
• slit-shaped openings 50 are introduced into the cover layer 40.
• the openings 50 are by means of an ultra-short pulse laser in the cover layer 40th
• the slot-shaped openings 50 are introduced into the cover layer 40 such that the longitudinal extensions LO of the slot-shaped openings 50 are formed parallel to the longitudinal extensions LE of the electrodes 31 and 32 (see FIGS. 3a and 3b) ,
• the slot-shaped openings 50 are formed parallel to each other.
• the slot-shaped openings 50 at least partially expose the upper sides 35 of the electrodes 31 and 32.
• the edge regions 39 are the portions of the upper side 35 that adjoin the side surfaces 36 of the electrodes 31 and 32.
• FIGS. 6a and 6b show a further embodiment of the invention
• the longitudinal extents LO extend perpendicular to the longitudinal extents LE of the electrodes 31 and 32.
• the slit-shaped openings 50 are formed continuously.
• Fig. 6 is a
• Electrodes 31 and 32 free but also the side 21 of the substrate 20. Thus, in Fig. 6b, not only the top sides 35 of the electrodes 31 and 32 but also the side surfaces 36 of the electrodes 31 and 32 are exposed.
• FIG. 7 another embodiment of the invention is shown, similar to that in Fig. 5b.
• the enlarged cross section through a sensor according to the invention 10 shows that sections 42 of the covering layer 40 can remain between the electrodes 31 and 32 despite the formation of slit-shaped openings 50, which are introduced in the illustrated example by means of the ultra-short-pulse laser 60.
• Fig. 5b here are the embodiment in Fig. 5b.
• Covering layer are rounded.
• a sensor 10 according to the invention is also shown in FIG. It is the gas flow direction S can be seen.
• the sensor 10 is arranged in the gas flow or in relation to the gas flow direction S in such a way that the longitudinal extensions LE of the electrodes 31 and 32 are perpendicular to
• Flow direction S are aligned.
• the first electrode 31 is negatively polarized in the illustrated example, whereas the second electrode 32 is positively poled.
• the slot-shaped openings 50 are formed continuously in the example shown. Between the slot-shaped openings 50, portions 45 of the cover layer 40 are formed. These sections 45 form comb-like elevations. Along this, the filaments 70 on the sensor 10 are particularly preferably formed.
• Elevations of the cover layer 45 can serve as forming filaments 70 as mechanical stabilization.
• Filaments 70 are understood as meaning chains of particles which are attached to one another, in particular chains of soot particles which are attached to one another.
• formed laser-structured cover layer 40 promotes the filament formation 70 of the soot particles, which form between the electrodes 31 and 32.
• Electrodes 31 and 32 can thus be bridged in a straight path by means of the sections 45.
• the sensitivity of the sensor according to the invention is significantly increased compared to known sensors. LIST OF REFERENCE NUMBERS

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• 2016
  • 2016-12-22 EP EP16206130.3A patent/EP3339833B1/de not_active Not-in-force
• 2017
  • 2017-12-20 US US16/472,530 patent/US11243157B2/en not_active Expired - Fee Related
  • 2017-12-20 KR KR1020197021064A patent/KR102221044B1/ko not_active Expired - Fee Related
  • 2017-12-20 WO PCT/EP2017/083701 patent/WO2018115054A1/de not_active Ceased
  • 2017-12-20 CN CN201780079623.4A patent/CN110402381B/zh not_active Expired - Fee Related
  • 2017-12-20 JP JP2019532951A patent/JP6997189B2/ja not_active Expired - Fee Related

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