JP4574411B2 - Wrinkle detection sensor and wrinkle detection method - Google Patents

Description

  The present invention relates to a wrinkle detection sensor and a wrinkle detection method. More particularly, the present invention relates to a soot detection sensor and a soot detection method capable of continuously detecting the amount of soot contained in gas passing through a gas flow path with high accuracy.

  There is an increasing need to remove particulates and harmful substances in exhaust gas from internal combustion engines, boilers and the like from the exhaust gas in consideration of environmental impact. In particular, regulations regarding the removal of particulates (hereinafter sometimes referred to as PM) discharged from diesel engines are in a direction to be strengthened both in Europe, the United States, and Japan, and this PM may be referred to as a diesel particulate filter (hereinafter referred to as DPF). ) Technology for reducing the amount of PM collected by a filter called) and discharged to the outside.

  As such a DPF, for example, a filter having a honeycomb structure in which a plurality of cells serving as fluid flow paths are formed by porous partition walls is used. By alternately sealing the cells, The porous partition walls constituting the film serve as a filter and can purify the exhaust gas.

  By the way, if such a filter for purifying gas containing PM is continuously used, the trapped PM blocks the surface of the partition wall, and the pressure loss increases, so that the filter performance deteriorates. In particular, in the case of a DPF mounted in an automobile, it is not preferable in that not only the filter performance is lowered but also the performance of the engine is lowered or the fuel consumption is deteriorated due to an increase in pressure loss. Therefore, when the amount of PM collected by the filter reaches an amount that requires regeneration, the filter is heated to burn and remove the collected PM (referred to as “regeneration”). Has been carried out.

  For example, as a method of regenerating the DPF, a heater is disposed by burning the fuel supplied by post injection (meaning that fuel is injected in the latter half of the explosion stroke or the exhaust stroke) or upstream of the DPF. Thus, a regeneration method or the like is known in which the temperature of the exhaust gas discharged is raised and the DPF is heated using the high-temperature exhaust gas.

  In the DPF currently put into practical use and proposed, the detection that the amount of PM collected by the filter has become a quantity that needs to be regenerated is, for example, before and after the filter due to the filter pressure loss at the inlet / outlet of the filter. The differential pressure of the exhaust pressure is detected by a DPF differential pressure sensor, and the value of the differential pressure is compared with a predetermined determination value by electronic control or the like (for example, see Patent Document 1).

In addition, a particulate detection element using the fact that soot (carbon fine particles) as PM has electrical conductivity has also been proposed (see, for example, Patent Document 2). The particulate detection element includes a heat-resistant electrical insulating member that captures conductive fine particles, and a pair of opposing electrode portions that are disposed on the heat-resistant electrical insulating member and measure the electrical resistance of the heat-resistant electrical insulating member. It consists of
JP 60-47937 A JP 59-60018 A

  However, regarding the method of detecting the differential pressure of the exhaust pressure before and after the filter by the DPF differential pressure sensor, when the engine operating condition changes, the flow rate and temperature of the exhaust gas that is discharged changes, and the reference filter pressure loss Changes significantly. For this reason, the method for directly detecting the differential pressure between the exhaust pressure before and after the filter described above has a problem that the detection accuracy is low.

  For this reason, a method is also proposed in which a judgment value is set for each engine operating condition, the data is stored as map data in the electronic control device in advance, and a judgment value corresponding to the engine operating condition is extracted. However, there is a problem that the above-described map cannot cope with changes in engine performance over time or changes due to engine differences.

  In addition, for particulate detection elements having a heat-resistant electrical insulation member that captures conductive fine particles, particulates (煤) are placed on the heat-resistant electrical insulation member to such an extent that conduction between a pair of electrode portions is ensured. Since the detection sensitivity cannot be obtained until the deposit is deposited, there has been a problem that the sensitivity and responsiveness relating to the low concentration are low.

  In Japan, considering the impact on the environment, for example, the introduction of an on-board diagnostic system (OBD) that diagnoses the functions of an exhaust gas purification system equipped with a DPF on the vehicle has been studied. The policy of obligatory installation is shown in vehicles after the 2008 model. In this case, the detection of a small amount of soot discharged through the DPF has been studied, but the conventional method described above is low in detection accuracy and responsiveness, and therefore used as an OBD detection sensor. It is difficult.

  The present invention has been made in view of the above-described problems, and a soot detection sensor and a soot detection method capable of detecting the amount of soot contained in gas passing through a gas flow path with high accuracy and continuously. I will provide a.

  The present invention provides the following wrinkle detection sensor and wrinkle detection method.

[1] A soot detection sensor that is installed in a gas flow path through which gas containing soot passes and detects the soot contained in the gas, the pair of conductive electrodes facing each other, and the pair of conductive One surface of the conductive electrode, and another surface of the dielectric electrode disposed in contact with the gas passing through the gas flow path. When a predetermined amount of the soot contained in the gas passing through the gas flow path adheres to the other surface of the dielectric, a creeping discharge is generated on the other surface of the dielectric. in conjunction with a voltage applying means is voltage Ru is applied, wherein the dielectric other surface creeping discharge is measured state of the pair of conductive electrodes at the time of generating, the soot contained in the gas A wrinkle detecting sensor for detecting the one of the dielectrics. A wrinkle detection sensor (hereinafter referred to as “first invention” ) in which a gap of 0.1 to 0.7 mm is provided in at least a part between the surface and the pair of conductive electrodes. ).

  [2] The soot detection sensor according to [1], wherein a DC voltage, an AC voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes.

  [3] The method according to [1] or [2], wherein the amount of soot contained in the gas is detected by measuring an amount of electric power consumed per unit time between the pair of conductive electrodes.煤 Detection sensor.

  [4] The soot detection sensor according to [1] or [2], wherein the amount of soot contained in the gas is detected by measuring a current value flowing between the pair of conductive electrodes.

  [5] The above [1] or [2], wherein the amount of the soot contained in the gas is detected by measuring the number of creeping discharges generated on the other surface of the dielectric per unit time.煤 detection sensor.

  [6] When an alternating voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes, the maximum voltage value of the applied voltage is measured to be included in the gas. The wrinkle detection sensor according to [1] or [2], wherein the wrinkle detection sensor detects an amount of the wrinkle.

[ 7 ] The voltage value applied between the pair of conductive electrodes is increased at predetermined time intervals to forcibly generate creeping discharge on the other surface of the dielectric. [7] The wrinkle detection sensor according to any one of to [ 6 ].

[ 8 ] A soot detection method for detecting soot contained in a gas passing through a gas flow path, a pair of conductive electrodes facing each other, and a dielectric having one surface sandwiched between the pair of conductive electrodes A body is disposed so that at least the other surface of the dielectric is in contact with the gas passing through the gas flow path, and the dielectric of the dielectric is interposed between the pair of conductive electrodes facing each other. When a predetermined amount of the soot contained in the gas passing through the gas flow path adheres to another surface, a voltage is applied so that creeping discharge is generated on the other surface of the dielectric, and the dielectric A soot detection method (hereinafter referred to as “second invention”) for detecting the soot contained in the gas by measuring the state of the pair of conductive electrodes when creeping discharge occurs on the other surface There is).

[ 9 ] The soot detection method according to [ 8 ], wherein a DC voltage, an AC voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes.

[ 10 ] The method according to [ 8 ] or [ 9 ], wherein the amount of soot contained in the gas is detected by measuring an amount of power consumed per unit time between the pair of conductive electrodes.煤 Detection method.

[ 11 ] The soot detection method according to [ 8 ] or [ 9 ], wherein the amount of soot contained in the gas is detected by measuring a current value flowing between the pair of conductive electrodes.

[ 12 ] The above [ 8 ] or [ 9 ], wherein the amount of soot contained in the gas is detected by measuring the number of creeping discharges generated on the other surface of the dielectric per unit time.煤 detection method.

[ 13 ] When an AC voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes, the maximum voltage value of the applied voltage is measured to be included in the gas. The wrinkle detection method according to [ 8 ] or [ 9 ], wherein the amount of wrinkle to be detected is detected.

[ 14 ] The above-mentioned [ 8 ]-[ 13 ], wherein a gap having a spacing of 0.1-0.7 mm is provided in at least a part between the one surface of the dielectric and the pair of conductive electrodes. The wrinkle detection method according to any one of the above.

[15] a predetermined time interval, increasing the voltage applied therebetween the pair of conductive electrodes, wherein the generating force the creeping discharge on the other surface of the dielectric [8] The wrinkle detection method according to any one of to [ 14 ].

  The soot detection sensor of the present invention can continuously detect the amount of soot contained in the gas passing through the gas flow path with high accuracy. In particular, since the soot detection sensor of the present invention can detect a very small amount of soot and the like, it can also be suitably used as an OBD detection sensor for detecting a decrease in performance or damage of the DPF. Further, the soot detection method of the present invention is a method capable of continuously detecting the amount of soot contained in the gas passing through the gas flow path with high accuracy.

  Hereinafter, embodiments of a wrinkle detection sensor and a wrinkle detection method according to the present invention (first and second inventions) will be described in detail with reference to the drawings. However, the present invention is construed as being limited thereto. However, various changes, modifications, and improvements can be made based on the knowledge of those skilled in the art without departing from the scope of the present invention.

  FIG. 1 is a cross-sectional view schematically showing one embodiment of a wrinkle detection sensor of the present invention (first invention). The soot detection sensor 1 of the present embodiment is a soot detection sensor 1 that is installed in a gas flow path 5 through which gas containing soot 4 passes and detects soot 4 contained in this gas, and is opposed to each other. A pair of conductive electrodes 3 (3a, 3b) and one surface 11 are sandwiched between the pair of conductive electrodes 3, and the other surface 12 is disposed so as to be in contact with the gas passing through the gas flow path 5. 4 having a predetermined shape of the dielectric 2 and included in the gas passing through the gas flow path 5 on the other surface 12 of the dielectric 2 between the pair of conductive electrodes 3 facing each other. When a predetermined amount adheres, a voltage is applied so that creeping discharge occurs on the other surface 12 of the dielectric 2. In the pair of conductive electrodes 3a and 3b of the wrinkle detection sensor 1 of the present embodiment shown in FIG. 1, one conductive electrode 3a is electrically connected to the power source 14, and the other conductive electrode 3b is connected. Grounded.

  Thus, between the pair of conductive electrodes 3 constituting the wrinkle detection sensor 1 of the present embodiment, the initial state, that is, the gas passing through the gas flow path 5 is disposed so as to be in contact with the gas. In the state where the ridge 4 is not attached to the other surface 12 of the dielectric 2, a voltage of a magnitude that does not cause creeping discharge is applied to the other surface 12. In this state, the gas passes through the gas flow path 5, and a predetermined amount of soot 4 adheres to the other surface 12 of the dielectric 2, so that the minimum necessary for creeping discharge on the surface 12 of the dielectric 2 is generated. When the potential difference value decreases, current easily flows on the surface 12 of the dielectric 2, and creeping discharge occurs on the other surface 12 of the dielectric 2.

  The soot 4 contained in the exhaust gas discharged from an internal combustion engine such as an engine has positive and negative charges at a substantially constant rate and distribution, and when entering the space where an electric field exists, it is electrostatically collected by an electric attractive force. The In the wrinkle detection sensor 1 of the present embodiment, since a voltage is applied to the pair of conductive electrodes 3, the other surface 12 of the dielectric 2 sandwiched between the pair of conductive electrodes 3 There is an electric field, and the trap 4 is electrostatically collected by this electric field. For this reason, for example, the detection is performed by collecting the soot 4 on the dielectric 2 of the soot detection sensor 1 instead of simply waiting for soot to accumulate on the other surface 12 of the dielectric 2. Therefore, it has excellent detection sensitivity.

  The larger the amount of soot 4 contained in the gas passing through the gas flow path 5, the more soot 4 is electrostatically collected in a short time, which is necessary for generating creeping discharge on the surface 12 of the dielectric 2. The minimum potential difference value decreases quickly. For this reason, it is contained in gas by measuring the electric energy and electric current value in the soot detection sensor 1 of this Embodiment, the frequency | count of the creeping discharge which arises on the other surface 12 of the dielectric material 2 per unit time, etc. It can be detected in terms of the amount of 煤 4.

  The type of voltage applied to the pair of conductive electrodes 3 constituting the soot detection sensor 1 is not particularly limited, but is a voltage that suitably causes creeping discharge when the soot 4 adheres to the other surface 12 of the dielectric 2. For example, a DC voltage, an AC voltage, a pulse voltage, or a sawtooth waveform voltage can be given as a suitable example.

  As described above, the soot detection sensor 1 according to the present embodiment is capable of measuring various physical measurement values obtained by the phenomenon in which the soot 4 adheres to the other surface 12 of the dielectric 2 to cause creeping discharge. The measurement value that can convert the amount of soot 4 contained in the gas from the value is selected and measured, and the amount of soot 4 contained in the gas is detected from the obtained predetermined measurement value.

  Specifically, for example, a method of detecting the amount of soot 4 contained in the gas by measuring the amount of power per unit time consumed between the pair of conductive electrodes 3, A method of detecting the amount of soot 4 contained in the gas by measuring the value of the current flowing between the pair of conductive electrodes 3 when creeping discharge occurs on the surface 12, and further, the dielectric per unit time The method etc. which detect the quantity of the soot 4 contained in gas by measuring the frequency | count of the creeping discharge which arises on the other surface 12 of the body 2 can be mentioned.

  For example, as a method of measuring the amount of power per unit time and detecting the amount of 煤 4, a DC voltage is applied between a pair of conductive electrodes 3 as shown in FIG. And a voltage signal proportional to the power consumption per unit time is output by the power measuring circuit 13. A method for calculating the amount of soot 4 contained in the gas can be mentioned based on the voltage signal thus obtained and the amount of gas passing through the gas flow path 5.

  Further, for example, the amount of soot 4 contained in the gas can be detected by measuring the value of the current flowing between the pair of conductive electrodes 3, and further, the dielectric 2 per unit time can be detected. By measuring the number of creeping discharges generated on the other surface 12, the amount of soot 4 contained in the gas can be detected.

  In addition, for example, when an alternating voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes 3, the maximum voltage value of the applied voltage is measured to be included in the gas. It is also possible to detect the amount of soot 4 that is produced. Thus, when a voltage (AC voltage, pulse voltage, sawtooth waveform voltage, or the like) whose voltage value changes with time is applied, the ridge 4 adheres to the surface 12 of the dielectric 2, The minimum potential difference value required when creeping discharge occurs changes, and the maximum voltage value described above changes accordingly. For this reason, the amount of soot 4 contained in the gas can be detected by measuring the maximum voltage value.

  In the soot detection sensor 1 of the present embodiment, when a predetermined amount of soot 4 adheres to the other surface 12 of the dielectric 2 to cause creeping discharge, the attached soot 4 is oxidized to carbon dioxide, It is discharged together with the gas passing through the gas flow path 5. For this reason, every time a creeping discharge occurs, the other surface 12 of the dielectric 2 returns to the initial state, that is, the state in which the soot 4 is not attached, and the soot 4 can be continuously detected. Although not particularly limited, for example, the voltage value applied between the pair of conductive electrodes 3 is increased at predetermined time intervals to force the other surface 12 of the dielectric 2 to be forced. It may be configured to cause creeping discharge. Further, when detecting soot 4 contained in the gas discharged from the engine of the automobile, creeping discharge is forcibly generated on the other surface 12 of the dielectric 2 when the engine is started, The surface 12 may be returned to the initial state. By configuring in this way, it is possible to detect the eyelid 4 with high accuracy.

  There are no particular restrictions on the shape of the pair of conductive electrodes 3 constituting the soot detection sensor 1 and the shape of the dielectric 2, and the other surface 12 of the dielectric 2 is included in the gas passing through the gas flow path 5. The ridges 4 adhere, preferably by electrostatic collection, and the voltage applied between the pair of conductive electrodes 3 effectively causes creeping discharge on the other surface 12 to which the ridges 4 adhere. For example, as shown in FIG. 2, a rod-shaped electrode (conductive electrode 3a) and a hollow cylindrical electrode (conductive electrode 3b) disposed outside the rod-shaped electrode are preferable. A wrinkle detection sensor 1 that includes a pair of conductive electrodes 3 configured of the above and a cylindrical dielectric 2 disposed between the pair of conductive electrodes 3 can be given.

  Further, as shown in FIG. 3, the pair of rod-shaped conductive electrodes 3a and 3b disposed at a predetermined interval and the pair of rod-shaped conductive electrodes 3a and 3b are disposed to cover the pair of rod-shaped conductive electrodes 3a and 3b. The wrinkle detection sensor 1 provided with the dielectric 2 may be sufficient. Here, FIG. 2 and FIG. 3 are cross-sectional views showing other examples of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment. 2 and 3, the same components as those in the wrinkle detection sensor shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 4 and 5, the pair of conductive electrodes 3a and 3b are plate-shaped, and the wrinkle detection is configured by sandwiching the dielectric 2 between the pair of plate-shaped conductive electrodes 3a and 3b. The sensor 1 may be used. In such a wrinkle detection sensor 1, the dielectric 2 may be larger than the conductive electrodes 3a and 3b as shown in FIG. 4, or the conductive electrodes 3a and 3b and the dielectric are shown in FIG. 2 may be substantially the same, or the dielectric 2 may be smaller than the conductive electrodes 3a and 3b. Here, FIG. 4 and FIG. 5 are perspective views showing other examples of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment. 4 and 5, the same components as those in the wrinkle detection sensor shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  Further, as shown in FIGS. 6 and 7, for example, a part of the pair of conductive electrodes 3a and 3b may be bent in the shape of a heel or the like. By positioning the bent portion on the other surface 12 side of the dielectric 2, creeping discharge is likely to occur on the other surface 12 to which the ridge 4 (see FIG. 1) adheres, and the detection sensitivity can be improved. . Here, FIG. 6 and FIG. 7 are cross-sectional views showing other examples of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment. 6 and 7, the same components as those in the wrinkle detection sensor shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  Further, as shown in FIGS. 8 and 9, a wrinkle detection sensor including a pair of rod-shaped conductive electrodes 3a and 3b and a dielectric 2 sandwiched between end surfaces of the pair of rod-shaped conductive electrodes 3a and 3b. 1 may be sufficient. Note that the conductive electrodes 3a and 3b constituting the wrinkle detection sensor 1 shown in FIG. 8 are cylindrical, and the conductive electrodes 3a and 3b constituting the wrinkle detection sensor 1 shown in FIG. 9 are square pillars. Here, FIG. 8 is a plan view showing another example of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment, and FIG. 9 is a wrinkle detection sensor of the present embodiment. It is a perspective view which shows the other example of a pair of electroconductive electrode and dielectric material which comprise. In FIGS. 8 and 9, elements that are configured in the same manner as the wrinkle detection sensor shown in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  Thus, about the shape of a pair of electroconductive electrodes 3a and 3b and the dielectric 2 which comprise the soot detection sensor 1 of this Embodiment, the dielectric to which soot 4 contained in the gas which passes a gas flow path adheres Any shape that can cause a creeping discharge on the other surface 12 of the two is sufficient. Although not particularly limited, as shown in FIG. 10, it is easy to cause creeping discharge on the other surface 12 of the dielectric 2 so that the generated creeping discharge is not dispersed to other parts. The portion where the distance between the pair of conductive electrodes 3a and 3b (shortest distance) is long on the surface where the dielectric 2 is not in contact with the pair of conductive electrodes 3a and 3b is between the pair of conductive electrodes 3a and 3b. It is preferable that the distance (shortest distance) is configured to be at least twice as long as the short part.

  Furthermore, in the soot detection sensor 1 of the present embodiment, a pair of conductive layers is used to facilitate the occurrence of creeping discharge on the other surface 12 of the dielectric 2 and to prevent the generated creeping discharge from being distributed to other parts. It is preferable that the distance X between the opposing electrodes 3, that is, the width of the portion where creeping 4 is deposited on the other surface 12 of the dielectric 2 to cause creeping discharge is 0.5 to 10 mm. If the distance X between the pair of conductive electrodes 3 facing each other is 0.5 mm or less, creeping discharge is generated only by a small amount of ridges 4 being attached, so that detection accuracy and resolution may be reduced. is there. Further, if the distance X between the pair of conductive electrodes 3 facing each other exceeds 10 mm, it takes too much time until the amount of creeping discharge occurs when the amount of ridges 4 is small, and the responsiveness. May decrease. Here, FIG. 10 is a cross-sectional view showing another example of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment. In FIG. 10, elements that are configured similarly to the wrinkle detection sensor shown in FIG.

  In the wrinkle detection sensor of the present embodiment, as shown in FIGS. 11, 12A, 12B, and 13, one surface 11 of the dielectric 2 and a pair of conductive properties It is preferable that a gap 15 having an interval of 0.1 to 0.7 mm is provided at least at a part between the electrode 3 and the electrode 3. Here, FIG. 11 is a perspective view showing another example of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment, and FIG. FIG. 12B is a cross-sectional view showing another example of a pair of conductive electrodes and a dielectric that constitute the soot detection sensor, and FIG. 12B shows another surface of the dielectric of the soot detection sensor shown in FIG. FIG. FIG. 13 is an enlarged cross-sectional view in which a part of another example of a pair of conductive electrodes and a dielectric constituting the wrinkle detection sensor of the present embodiment is enlarged. In addition, in FIGS. 11, 12A, 12B, and 13, each element configured in the same manner as the wrinkle detection sensor shown in FIG. Omitted.

  As described above, when the gap 15 having an interval of 0.1 to 0.7 mm is provided in at least a part between the one surface 11 of the dielectric 2 and the pair of conductive electrodes 3, the gap An electric field is formed at 15, and the basket 4 is easily electrostatically collected in the gap 15. In addition, since the creeping 4 is collected in the gap 15, creeping discharge occurs, so that the frequency of creeping discharge increases and the voltage value at which creeping discharge occurs also decreases. Thus, by measuring these values, the amount of soot 4 contained in the gas passing through the gas flow path can be detected with high accuracy and continuously.

  When the amount of soot 4 contained in the gas is detected by the soot detection sensor 1 according to the present embodiment, for example, as shown in FIG. The other part of the wrinkle detection sensor 1 is preferably disposed outside the gas flow path 5 and used. As described above, in the wrinkle detection sensor 1 according to the present embodiment, the other surface 12 of the dielectric 2 is a substantial sensor portion, so that at least the other surface 12 of the dielectric 2 is a measurement object. What is necessary is just to be arrange | positioned so that it may contact gas. Further, as shown in FIG. 15, the soot detection sensor 1 of the present embodiment is installed, for example, in the gas flow path 5a immediately after the engine, and is used to detect the soot 4 immediately after being discharged from the engine. It can also be used to determine when to regenerate the DPF 6, or, for example, installed in the gas flow path 5b immediately after the filter, such as the DPF 6, so that the trace 4 that has passed through the DPF 6 or hardly contained It can also be used for detection and for devices that self-diagnose functions such as exhaust gas purification systems on the vehicle. Here, FIG.14 and FIG.15 is explanatory drawing which shows typically the state which installed the soot detection sensor of this Embodiment in the gas flow path. In addition, the arrow shown in FIG. 15 shows the flow of exhaust gas.

  As the conductive material constituting the pair of conductive electrodes 3a and 3b as shown in FIG. 1, for example, iron (Fe), nickel (Ni), chromium (Cr), molybdenum (Mo), platinum (Pt ), Gold (Au), silver (Ag), and copper (Cu) group. Such a metal-containing material is excellent in heat resistance and corrosion resistance, and can be suitably used as the conductive electrodes 3a and 3b of the soot detection sensor 1 that may be used in a high temperature or corrosive gas atmosphere.

  In addition, the dielectric 2 for generating creeping discharge preferably includes at least one selected from the group consisting of alumina, zirconia, zircon, silicon nitride, sialon, alumina titanate, cordierite, and mullite. By using the dielectric 2 made of such a material, creeping discharge can be favorably generated on the surface 12 thereof.

  As described above, the soot detection sensor 1 of the present embodiment causes a predetermined amount of soot 4 to adhere to the other surface 12 of the dielectric 2 to cause creeping discharge of the other surface 12 of the dielectric 2. The creepage discharge is generated on the other surface 12 of the dielectric 2 by reducing the minimum potential difference value required at this time. For this reason, a voltage lower than the voltage at which the dielectric 2 starts discharging in the initial clean state (that is, the state in which no soot is attached) is applied between the pair of conductive electrodes 3a and 3b. Although not particularly limited, it is preferable to apply a voltage of 20 to 80% of the voltage at which the dielectric 2 starts discharging in the initial clean state as the value of this voltage. If the applied voltage is less than 20%, a large amount of soot must adhere to the other surface 12 of the dielectric 2 before discharge occurs, and the detection sensitivity may decrease. On the other hand, when the applied voltage exceeds 80%, discharge is likely to occur and the detection accuracy may be lowered.

  Next, the wrinkle detection method of the present invention (second invention) will be described. The wrinkle detection method of the present embodiment can be realized using the above-described embodiment of the first invention (wrinkle detection sensor). For example, in the case of detecting wrinkles using the wrinkle detection sensor 1 shown in FIG. 1, one surface 11 is sandwiched between a pair of conductive electrodes 3a and 3b facing each other and a pair of conductive electrodes 3a and 3b. The dielectric 2 is disposed so that at least the other surface 12 of the dielectric 2 is in contact with the gas passing through the gas flow path 5, and between the pair of conductive electrodes 3a and 3b facing each other. When a predetermined amount of soot 4 contained in the gas passing through the gas flow path 5 adheres to the other surface 12 of the dielectric 2, a voltage is applied so that creeping discharge occurs on the other surface 12 of the dielectric 2. The soot detection method detects the soot 4 contained in the gas by measuring the state of the pair of conductive electrodes 3a and 3b when creeping discharge occurs on the other surface 12 of the dielectric 2.

  In the wrinkle detection method of the present embodiment, in a state where the wrinkles 4 are not attached to the other surface 12 of the dielectric 2, a voltage having a magnitude that does not cause creeping discharge on the other surface 12 is applied to the pair of conductive layers. When the gas passes through the gas flow path 5 and is applied to the conductive electrodes 3a and 3b and a predetermined amount of soot 4 adheres to the other surface 12 of the dielectric 2, a creeping discharge occurs on the surface 12 of the dielectric 2. This is a soot detection method that utilizes the fact that the minimum potential difference value required for the dielectric layer 2 decreases, current easily flows on the surface 12 of the dielectric 2, and creeping discharge occurs on the other surface 12 of the dielectric 2. In the soot detection method of the present embodiment, various physical measurement values obtained by the phenomenon in which soot 4 adheres to the other surface 12 of the dielectric 2 to cause creeping discharge, and these measured values are converted into gas. The measurement value that can convert the amount of soot 4 contained is selected and measured, and the amount of soot 4 contained in the gas is detected from the obtained predetermined measurement value. In the soot detection method of the present embodiment, the above-described measured values include various values that can be measured from the pair of conductive electrodes 3a and 3b when creeping discharge occurs on the other surface 12 of the dielectric 2. The measured value can be exemplified, and for example, the electric energy and the current value, and the number of creeping discharges generated on the other surface 12 of the dielectric 2 per unit time can be exemplified.

  The type of voltage applied to the pair of conductive electrodes 3 is not particularly limited. For example, a direct current voltage may be used so that creeping discharge is suitably generated when the ridge 4 is attached to the other surface 12 of the dielectric 2. It is preferable to apply an alternating voltage, a pulse voltage, or a sawtooth waveform voltage.

  As described above, in the soot detection method of this embodiment, various measurement values that can be measured from the pair of conductive electrodes 3a and 3b are measured to detect the soot 4 contained in the gas. For example, as a method of measuring the amount of electric power per unit time and detecting the amount of 煤 4, a predetermined power source 14 is used between the pair of conductive electrodes 3 as shown in FIG. A voltage is applied and a voltage signal proportional to the amount of power consumed per unit time is output by the power measuring circuit 13, and the voltage signal and the amount of gas that has passed through the gas flow path 5 are used to generate A method for calculating the amount can be mentioned.

  Further, for example, the amount of soot 4 contained in the gas can be detected by measuring the value of the current flowing between the pair of conductive electrodes 3, and further, the dielectric 2 per unit time can be detected. By measuring the number of creeping discharges generated on the other surface 12, the amount of soot 4 contained in the gas can be detected.

  In addition, for example, when an alternating voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes 3, the maximum voltage value of the applied voltage is measured to be included in the gas. It is also possible to detect the amount of soot 4 that is produced. As described above, when a voltage whose voltage value changes with time (an AC voltage, a pulse voltage, a sawtooth waveform voltage, or the like) is applied, the ridge 4 adheres to the other surface 12 of the dielectric 2. Thus, the minimum potential difference value required when creeping discharge occurs changes, and the maximum voltage value described above changes accordingly. For this reason, the amount of soot 4 contained in the gas can be detected by measuring the maximum voltage value.

  In the soot detection method of the present embodiment, when a predetermined amount of soot 4 adheres to the other surface 12 of the dielectric 2 to cause creeping discharge, the attached soot 4 is oxidized to carbon dioxide, and the gas flow path It is discharged together with the gas passing through 5. For this reason, every time a creeping discharge occurs, the other surface 12 of the dielectric 2 returns to the initial state, that is, the state in which the soot 4 is not attached, and the soot 4 can be continuously detected. Although not particularly limited, for example, the voltage value applied between the pair of conductive electrodes 3 is increased at predetermined time intervals to force the other surface 12 of the dielectric 2 to be forced. Creeping discharge may be generated. Further, when detecting soot 4 contained in the gas discharged from the engine of the automobile, creeping discharge is forcibly generated on the other surface 12 of the dielectric 2 when the engine is started, The surface 12 may be returned to the initial state. By configuring in this way, it is possible to detect the eyelid 4 with high accuracy.

  Further, when the amount of soot 4 contained in the gas is detected by the soot detection method of the present embodiment, for example, as shown in FIG. It is preferable to insert and use other portions of the wrinkle detection sensor 1 outside the gas flow path 5. Since the soot detection method of the present embodiment detects soot 4 contained in the gas by causing soot on the other surface 12 of the dielectric 2 to cause creeping discharge, at least the dielectric Two other surfaces 12 may be disposed so as to be in contact with the gas to be measured. Moreover, in the soot detection method of this Embodiment, as shown in FIG. 15, for example, the soot detection sensor 1 is installed in the gas flow path 5a immediately after the engine, and the soot 4 immediately after being discharged from the engine It can also be used to determine when to regenerate the DPF 6 for detection. For example, the soot detection sensor 1 is installed in the gas flow path 5b immediately after the filter such as the DPF 6 and passes through the DPF 6. It can also be used for self-diagnosis of the functions of the exhaust gas purification system etc. on the vehicle by detecting the soot 4 that is hardly contained or hardly contained.

  As described above, the soot detection method of the present embodiment is necessary for causing a predetermined amount of soot 4 to adhere to the other surface 12 of the dielectric 2 and causing creeping discharge on the surface 12 of the dielectric 2. By reducing the minimum potential difference value, creeping discharge is generated on the other surface 12 of the dielectric 2. For this reason, there is no particular limitation between the pair of conductive electrodes 3a and 3b, but the dielectric 2 starts to discharge in an initial clean state (ie, a state in which no soot is attached). It is preferable to apply a voltage of 20 to 80% of the voltage. If the voltage to be applied is less than 20%, a large amount of soot must adhere to the other surface 12 of the dielectric 2 before discharge occurs, and the detection sensitivity may decrease. On the other hand, if the applied voltage exceeds 80%, discharge is likely to occur and the detection accuracy may be lowered.

  The pair of conductive electrodes 3 and the dielectric 2 used in the wrinkle detection method of the present embodiment is a pair of conductive electrodes and dielectrics used in the above-described embodiment of the first invention (wrinkle detection sensor). What was comprised similarly to the body can be used suitably, and it is preferable that it is comprised from the shape and material which were demonstrated in embodiment of 1st invention.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1
As shown in FIG. 14, a wrinkle detection sensor 1 having a pair of conductive electrodes 3 facing each other and a dielectric 2 having a predetermined shape with one surface 11 sandwiched between the pair of conductive electrodes 3 is manufactured. did. The dielectric 2 was made using zircon, and the pair of conductive electrodes 3 was made using an iron-nickel-chromium alloy. In the soot detection sensor of the present embodiment, the distance between the pair of conductive electrodes facing each other, that is, the length of the shortest distance of the other surface of the dielectric where the creeping discharge actually occurs (hereinafter, “the creeping discharge distance”). Was 5 mm.

  Such a soot detection sensor 1 is in contact with the gas passage 5 through which the exhaust gas discharged from the burner using light oil fuel passes, and the other surface 12 of the dielectric 2 is in contact with the gas passing through the gas passage 5. When a predetermined amount of ridges 4 adhere to the other surface 12 of the dielectric 2 between the pair of conductive electrodes 3, a creeping discharge is generated on the other surface 12 of the dielectric 2. A voltage was applied. In this example, a voltage having a set voltage value of 3 kV, a pulse waveform, a pulse width of 100 nsec, and a period of 1000 Hz was applied between a pair of conductive electrodes. Table 1 shows the respective values. The set voltage value is a voltage value set in the power supply.

A burner using light oil fuel was burned, and gas generated from the burner (exhaust gas including soot) was vented to the gas flow path. While maintaining the gas flow rate constant, the concentration (mg / m ³ ) of soot contained in the gas is changed, the time average current (nA) flowing between the pair of conductive electrodes, A test was conducted to measure power (mW), voltage (V) applied between a pair of conductive electrodes, and the number of creeping discharges per minute (times / min). The measurement results are shown in Table 1. Table 1 shows the flow rate (m / sec) of the gas passing through the gas flow path, the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.).

The obtained time average current (nA) flowing between the pair of conductive electrodes, time average power (mW), voltage (V) applied between the pair of conductive electrodes, and per minute The number of creeping discharges (times / min) changes corresponding to the soot concentration (mg / m ³ ), and by measuring the above-mentioned value, the soot concentration contained in the gas can be detected. It turns out that you can.

(Example 2)
Similar to the soot detection sensor of Example 1 except that the creeping discharge distance is 3 mm, a voltage having a set voltage value of 1 kV, a pulse waveform, a pulse width of 50 nsec, and a frequency of 500 Hz is applied between a pair of conductive electrodes. The soot detection sensor configured as described above was manufactured, this soot detection sensor was installed in the gas flow path, and the same test as in Example 1 was performed. Time average current (nA) flowing between the pair of conductive electrodes, time average power (mW), voltage applied between the pair of conductive electrodes (V), number of creeping discharges per minute ( Table 1 shows the gas flow rate (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.).

(Example 3)
A wrinkle detection sensor having the same configuration as that of the wrinkle detection sensor of Example 1 was manufactured except that a creeping discharge distance was 3 mm and a DC voltage having a set voltage value of 2 kV was applied between a pair of conductive electrodes. The soot detection sensor was installed in the gas flow path, and the same test as in Example 1 was performed. Time average current (nA) flowing between the pair of conductive electrodes, time average power (mW), voltage applied between the pair of conductive electrodes (V), number of creeping discharges per minute ( Table 1 shows the gas flow rate (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.).

Example 4
A soot detection configured in the same manner as the soot detection sensor of Example 1 except that the creeping discharge distance is 3 mm, and an AC voltage having a set voltage value of 3 kV and a period of 60 Hz is applied between a pair of conductive electrodes. A sensor was manufactured, and this soot detection sensor was installed in the gas flow path, and the same test as in Example 1 was performed. Time average current (nA) flowing between the pair of conductive electrodes, time average power (mW), voltage applied between the pair of conductive electrodes (V), number of creeping discharges per minute ( Table 1 shows the gas flow rate (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.).

In the soot detection sensors of Examples 2 to 4 as well, each measurement value is changed by changing the concentration (mg / m ³ ) of soot contained in the gas, and any one of these measurements should be performed. Accordingly, it is possible to detect the concentration of soot contained in the gas (mg / m ^3).

(Example 5)
Example except that the creeping discharge distance is 0.5 mm and a voltage having a set voltage value of 0.8 kV, a sawtooth waveform, a pulse width of 0.03 nsec, and a period of 0.03 Hz is applied between a pair of conductive electrodes. A soot detection sensor configured in the same manner as the soot detection sensor 1 is manufactured, this soot detection sensor is installed in the gas flow path, the same test as in Example 1 is performed, and between the pair of conductive electrodes Changes in the measured maximum voltage value (V) were measured. The measured maximum voltage value (V), the flow rate of the gas passing through the gas flow path (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.) It is shown in 2.

As shown in Table 2, in the soot detection sensor of Example 5, a sawtooth waveform voltage of 0.8 kV is applied as the set voltage value. However, the set voltage value is obtained by attaching soot to the surface of the dielectric. Since creeping discharge occurs at a lower voltage, the measured maximum voltage value (V) decreases with the soot concentration (mg / m ³ ). Therefore, the concentration (mg / m ³ ) of soot contained in the gas can be detected by measuring the change in the maximum voltage value (V) between the pair of conductive electrodes.

(Example 6)
A soot detection sensor configured in the same manner as the soot detection sensor of Example 5 except that a creeping discharge distance is 1 mm and an AC voltage having a set voltage value of 2 kV and a period of 60 Hz is applied between a pair of conductive electrodes. The soot detection sensor was installed in the gas flow path, and the same test as in Example 5 was performed. The measured maximum voltage value (V), the flow rate of the gas passing through the gas flow path (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.) It is shown in 2.

(Example 7)
Similar to the soot detection sensor of Example 5 except that the creeping discharge distance is 1 mm and a voltage having a set voltage value of 2 kV, a pulse waveform, a pulse width of 100 nsec, and a cycle of 500 Hz is applied between a pair of conductive electrodes. The configured soot detection sensor was manufactured, and this soot detection sensor was installed in the gas flow path, and the same test as in Example 5 was performed. The measured maximum voltage value (V), the flow rate of the gas passing through the gas flow path (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.) It is shown in 2.

Also in the soot detection sensors of Examples 6 and 7, the maximum voltage value (V) between the pair of conductive electrodes is changed by changing the soot concentration (mg / m ³ ) contained in the gas. The concentration (mg / m ³ ) of soot contained in the gas can be detected by measuring the maximum voltage value (V) between the pair of conductive electrodes.

(Example 8)
Similar to the soot detection sensor of Example 1, except that the creeping discharge distance is 3 mm and a voltage having a set voltage value of 2 kV, a pulse waveform, a pulse width of 50 nsec, and a period of 1000 Hz is applied between a pair of conductive electrodes. A configured soot detection sensor was manufactured, and this soot detection sensor was installed in the gas flow path, and the same test as in Example 1 was performed. In the soot detection sensor of this embodiment, the voltage value applied between the pair of conductive electrodes is increased approximately four times for several seconds every 300 seconds, and forced on the other surface of the dielectric. A creeping discharge was generated. When measuring continuously for a long time, each measured value may become unstable gradually as time elapses. Since the dielectric is in an initial state (a state in which no soot is attached) every time the occurrence of the occurrence of the occurrence of the above, highly accurate and stable soot detection can be performed continuously for a long time.

Example 9
As shown in FIGS. 12A and 12B, a pair of conductive electrodes 3 facing each other, one surface 11 is sandwiched between the pair of conductive electrodes 3, and the other surface 12 is a gas flow. A dielectric 2 having a predetermined shape arranged so as to be in contact with the gas passing through the path 5, and at least partly between one surface 11 of the dielectric 2 and the pair of conductive electrodes 3. The wrinkle detection sensor 1 provided with a gap 15 having a width of 0.4 mm was manufactured. The dielectric 2 was made using zircon, and the pair of conductive electrodes 3 was made using an iron-nickel-chromium alloy. The creeping discharge distance in the soot detection sensor of this example was 1 mm.

The soot detection sensor of this example was installed in the gas flow path, and the same test as in Example 5 was performed. The measured maximum voltage value (V), the flow rate of the gas passing through the gas flow path (m / sec), the concentration of soot contained in the gas (mg / m ³ ), and the gas temperature (° C.) 3 shows.

In the soot detection sensor of Example 9 as well, as in the soot detection sensor of Example 5, the maximum concentration between the pair of conductive electrodes can be obtained by changing the concentration (mg / m ³ ) of soot contained in the gas. The voltage value (V) is changing, and the concentration (mg / m ³ ) of soot contained in the gas is detected by measuring the maximum voltage value (V) between the pair of conductive electrodes. Can do.

  Since the soot detection sensor of the present invention can detect the amount of soot contained in the gas passing through the gas flow path with high accuracy and continuously, for example, it is installed in the gas flow path immediately after the engine, It can also be used to detect the soot immediately after being discharged from the pipe, and can be used to determine when to regenerate the DPF. For example, the filter can be installed in a gas flow path immediately after the filter such as a DPF. It can also be used for a device for self-diagnosis of functions such as an exhaust gas purification system on a vehicle by detecting traces or soot that are hardly contained. In addition, the soot detection method of the present invention is a method capable of continuously detecting the amount of soot contained in the gas passing through the gas flow path with high accuracy. For example, the soot detection immediately after being discharged from the engine This amount can be used to determine when to regenerate the DPF, or to detect soot that has passed through the filter or is hardly contained.

It is sectional drawing which shows typically one Embodiment of the wrinkle detection sensor of this invention. It is sectional drawing which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is sectional drawing which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is a perspective view which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is a perspective view which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is sectional drawing which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is sectional drawing which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is a top view which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is a perspective view which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is sectional drawing which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is a perspective view which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is sectional drawing which shows the other example of a pair of electroconductive electrode and dielectric material which comprise one Embodiment of the wrinkle detection sensor of this invention. It is a top view of the other surface side of the dielectric of the wrinkle detection sensor shown to Fig.12 (a). It is the expanded sectional view which expanded a part of other example of a pair of electroconductive electrode and dielectric material which comprises one Embodiment of the wrinkle detection sensor of this invention. It is explanatory drawing which shows typically the state which installed one Embodiment of the soot detection sensor of this invention in the gas flow path. It is explanatory drawing which shows typically the state which installed one Embodiment of the soot detection sensor of this invention in the gas flow path.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Soot detection sensor, 2 ... Dielectric material, 3 ... A pair of electroconductive electrode, 3a, 3b ... Conductive electrode, 4 ... Soot, 5, 5a, 5b ... Gas flow path, 6 ... DPF, 11 ... Surface (dielectric) One surface of the body), 12 surface (other surface of the dielectric), 13 power measuring circuit, 14 power source, 15 gap, X the distance between the pair of conductive electrodes.

Claims (15)

A soot detection sensor that is installed in a gas flow path through which soot-containing gas passes and detects the soot contained in the gas,
A pair of conductive electrodes facing each other, and a dielectric disposed so that one surface is sandwiched between the pair of conductive electrodes and the other surface is in contact with the gas passing through the gas flow path. With
When a predetermined amount of the soot contained in the gas passing through the gas flow path adheres to the other surface of the dielectric between the pair of conductive electrodes facing each other, the dielectric and has a voltage application means a voltage Ru applied to creeping discharge is generated on the other surface, to measure the state of the pair of conductive electrodes when creeping discharge is generated in the other surface of the dielectric A soot detection sensor for detecting the soot contained in the gas ,
A wrinkle detection sensor in which a gap of 0.1 to 0.7 mm is provided in at least a part between the one surface of the dielectric and the pair of conductive electrodes .   The soot detection sensor according to claim 1, wherein a DC voltage, an AC voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes.   The soot detection sensor according to claim 1 or 2, wherein the amount of soot contained in the gas is detected by measuring an amount of power per unit time consumed between the pair of conductive electrodes.   3. The soot detection sensor according to claim 1, wherein the amount of soot contained in the gas is detected by measuring a current value flowing between the pair of conductive electrodes.   The soot detection sensor according to claim 1 or 2, wherein the amount of soot contained in the gas is detected by measuring the number of creeping discharges generated on the other surface of the dielectric per unit time.   When an alternating voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes, the maximum voltage value of the applied voltage is measured, whereby the gas included in the gas is measured. The wrinkle detection sensor according to claim 1 or 2 that detects the amount of. A predetermined time interval, increasing the voltage applied therebetween the pair of conductive electrodes, one of the dielectric the other claims forcibly cause creeping discharge on the surface 1-6 of the Crab detection sensor according to crab. A soot detection method for detecting soot contained in a gas passing through a gas flow path,
A pair of conductive electrodes opposed to each other and a dielectric having one surface sandwiched between the pair of conductive electrodes are in contact with at least the other surface of the dielectric in contact with the gas passing through the gas flow path. Arranged so that
When a predetermined amount of the soot contained in the gas passing through the gas flow path adheres to the other surface of the dielectric between the pair of conductive electrodes facing each other, the dielectric A voltage is applied so that creeping discharge is generated on the other surface, and the state of the pair of conductive electrodes when the creeping discharge is generated on the other surface of the dielectric is measured and included in the gas. A wrinkle detection method for detecting the wrinkles. The soot detection method according to claim 8 , wherein a DC voltage, an AC voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes. The soot detection method according to claim 8 or 9 , wherein the amount of soot contained in the gas is detected by measuring an amount of power per unit time consumed between the pair of conductive electrodes. The soot detection method according to claim 8 or 9 , wherein an amount of the soot contained in the gas is detected by measuring a value of a current flowing between the pair of conductive electrodes. The soot detection method according to claim 8 or 9 , wherein the amount of soot contained in the gas is detected by measuring the number of creeping discharges generated on the other surface of the dielectric per unit time. When an alternating voltage, a pulse voltage, or a sawtooth waveform voltage is applied between the pair of conductive electrodes, the maximum voltage value of the applied voltage is measured, whereby the gas included in the gas is measured. The method for detecting wrinkles according to claim 8 or 9 , wherein the amount of the wrinkles is detected. The scissors according to any one of claims 8 to 13 , wherein a gap having an interval of 0.1 to 0.7 mm is provided in at least a part between the one surface of the dielectric and the pair of conductive electrodes. Detection method. A predetermined time interval, increasing the voltage applied therebetween the pair of conductive electrodes, one of said dielectric of said other surface to force the claims 8 to 14, causing creeping discharge The method for detecting wrinkles according to crab.

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