WO2009031600A2 - Method for detecting distribution of trapped particulate matter, device for detecting distribution of trapped particulate matter and exhaust gas purifying device - Google Patents

Method for detecting distribution of trapped particulate matter, device for detecting distribution of trapped particulate matter and exhaust gas purifying device Download PDF

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Publication number
WO2009031600A2
WO2009031600A2 PCT/JP2008/065928 JP2008065928W WO2009031600A2 WO 2009031600 A2 WO2009031600 A2 WO 2009031600A2 JP 2008065928 W JP2008065928 W JP 2008065928W WO 2009031600 A2 WO2009031600 A2 WO 2009031600A2
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WO
WIPO (PCT)
Prior art keywords
trapped
electromagnetic wave
particulate matter
filter
amount
Prior art date
Application number
PCT/JP2008/065928
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French (fr)
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WO2009031600A3 (en
Inventor
Hitoshi Kato
Kazunob Ishibashi
Shigeki Daido
Takayuki Shibuya
Original Assignee
Toyota Jidosha Kabushiki Kaisha
Nippon Soken, Inc.
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Application filed by Toyota Jidosha Kabushiki Kaisha, Nippon Soken, Inc. filed Critical Toyota Jidosha Kabushiki Kaisha
Publication of WO2009031600A2 publication Critical patent/WO2009031600A2/en
Publication of WO2009031600A3 publication Critical patent/WO2009031600A3/en

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N9/00—Electrical control of exhaust gas treating apparatus
    • F01N9/002—Electrical control of exhaust gas treating apparatus of filter regeneration, e.g. detection of clogging
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2240/00—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being
    • F01N2240/04—Combination or association of two or more different exhaust treating devices, or of at least one such device with an auxiliary device, not covered by indexing codes F01N2230/00 or F01N2250/00, one of the devices being an electric, e.g. electrostatic, device other than a heater
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2550/00—Monitoring or diagnosing the deterioration of exhaust systems
    • F01N2550/04—Filtering activity of particulate filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/05—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics the means being a particulate sensor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/12—Other sensor principles, e.g. using electro conductivity of substrate or radio frequency
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2560/00—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics
    • F01N2560/14—Exhaust systems with means for detecting or measuring exhaust gas components or characteristics having more than one sensor of one kind
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/022—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous
    • F01N3/0222—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters characterised by specially adapted filtering structure, e.g. honeycomb, mesh or fibrous the structure being monolithic, e.g. honeycombs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/02—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust
    • F01N3/021—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters
    • F01N3/023—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles
    • F01N3/025—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust
    • F01N3/0253—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for cooling, or for removing solid constituents of, exhaust by means of filters using means for regenerating the filters, e.g. by burning trapped particles using fuel burner or by adding fuel to exhaust adding fuel to exhaust gases
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B37/00—Engines characterised by provision of pumps driven at least for part of the time by exhaust
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/40—Engine management systems

Definitions

  • the present invention relates to a method for detecting the distribution of trapped particulate matter, and a device for detecting the distribution of trapped particulate matter.
  • the present invention can be used to detect the distribution of PM accumulated in a filter that is disposed in an exhaust system of a diesel engine, for example.
  • a trap-type exhaust gas purifying device and an open-type exhaust gas purifying device (straight-flow) are well known as the conventionally developed exhaust gas purifying device for diesel engines.
  • a plugged type honeycomb body made of ceramic diesel PM filter
  • This filter is prepared by plugging ends of openings of cells of the ceramic honeycomb body alternately in a checkered pattern, for example, and includes flow-in side cells plugged at the exhaust gas downstream side, flow-out side cells that are adjacent to the flow-in side cells and plugged at the exhaust gas upstream side, and cell partition walls adapted to partition the flow-in side cells and the flow-out side cells.
  • This filter filtrates exhaust gas with fine pores of the cell partition walls to trap PM, thereby restraining emission thereof.
  • the exhaust pressure drop increases in the filter due to the accumulation of PM so that the filter is needed to be regenerated by periodically removing the accumulated PM with some means.
  • the regeneration process has been carried out by adding a reducing agent such as fuel to exhaust gas, generating ignition in the filter of which the temperature is raised, and burning PM trapped in the filter with resultant combustion heat.
  • a forced regeneration of the filter has been also carried out by disposing an oxidation catalyst on the upstream side of the filter, generating combustion with the oxidation catalyst to raise the temperature of exhaust gas, and supplying a high temperature exhaust gas to the filter.
  • a data of the amount of emitted PM relative to the engine operation condition is stored in ECU as a map data, the amount of emitted PM is estimated from an integrated value in the operation time, and the amount of trapped PM is estimated from the cumulating of the estimated amount of emitted PM. And at the time the amount of trapped PM is judged to exceed a predetermined level, the exhaust gas temperature is raised forcibly to regenerate the filter.
  • Japanese patent application laid-open No. 2005-325771 discloses a method of detecting an electric current or electric voltage, which is generated in a secondary coil wound around an outer periphery of a trap case when an alternating current is passed through a primary coil wound around the outer periphery of the trap case, to compute the amount of trapped PM from the detected electric current or electric voltage.
  • an induced electromotive force corresponding to the amount of trapped PM is generated so that the amount of trapped PM can be computed by detecting the electric current or electric voltage, which is generated in the secondary coil.
  • Japanese patent application laid-open No. HeM 0-220219 proposes an exhaust gas purifying device with which the amount of PM is detected by measuring the intensity of an electromagnetic wave with a microwave sensor.
  • This technique utilizes that when PM deposits on a filter, the dielectric constant and the dielectric loss of the filter vary, the phase of microwave in the filter shifts, and consequently, the intensity of the microwave varies, and the amount of deposited PM is detected from the variation in the intensity of the microwave by fixing the microwave detecting portion, and measuring the intensity of the microwave in that portion.
  • the microwave of 2.45 GHz which is normally used as the microwave, has a wavelength of about 12 cm so that the resolving power is low, and consequently, the local variation in the amount of trapped PM cannot be detected.
  • a physical amount related to the average amount of trapped PM or the total amount of trapped PM in the whole of the filter can be detected, but it is difficult to detect the distribution of trapped PM in the filter.
  • the amount of accumulated PM at an exhaust gas upstream side thereof may become larger than that at an exhaust gas downstream side thereof.
  • the amount of accumulated PM in an outer peripheral part of the filter, from which heat is readily taken away becomes larger than that in an inner peripheral part thereof. Therefore, even if the average amount of trapped PM or the total amount of trapped PM is detected, the amount of information has been insufficient for accurately judging whether the regeneration process should be carried out or not.
  • the present invention has been made in view of the above-described circumstances, and has the technical problem of readily detecting the distribution of trapped particulate matter that absorbs electromagnetic waves, such as PM, accurately with a non-destructive detecting method.
  • a method for detecting the distribution of trapped particulate matter in accordance with the present invention includes the steps of applying an electromagnetic wave with a frequency of several tens GHz to several THz to a trap case that has trapped particulate matter, from an outside thereof, detecting the intensity of the electromagnetic wave passed through the trap case, and substituting the detected intensity for a relational equation between a prescribed intensity of the electromagnetic wave and the amount of trapped particulate matter to compute the amount of trapped particulate matter, and these steps are carried out in a plurality of portions in the trap case, thereby detecting the distribution of trapped particulate matter in the trap case.
  • the device for detecting the distribution of trapped particulate matter in accordance with the present invention includes electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a plurality of portions in a trap case that has trapped particulate matter, from an outside thereof, electromagnetic wave receiving means for detecting the intensity of the electromagnetic wave that has passed through the plurality of portions in the trap case, and computing means for computing the amount of trapped particulate matter from the intensity detected with the electromagnetic wave receiving means and computing the distribution of trapped particulate matter in the trap case.
  • the exhaust gas purifying device in accordance with the present invention includes a filter disposed in an exhaust gas passage for trapping PM mainly composed of carbon, a case for accommodating the filter, electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a plurality of portions in the filter from an entrance window provided in the case, electromagnetic wave receiving means for detecting the intensity of the electromagnetic wave that has passed through the filter and radiated from a radiation window provided in the case, and computing means for computing the distribution of trapped particulate matter from the intensity detected with the electromagnetic wave receiving means.
  • the amount of trapped particulate matter in each of applied portions of an electromagnetic wave is detected using the electromagnetic wave with a frequency of several tens GHz to several THz (wavelength is on a millimeter level) and utilizing the absorption of the electromagnetic wave with the particulate matter, and the distribution of trapped particulate matter is detected by detecting the amount of trapped particulate matter in each of a plurality of portions so that the distribution of trapped particulate matter in the trap case can be detected with a high accuracy.
  • the regeneration process can be carried out before the amount of trapped PM locally increases too much, whereby the melting of the filter due to the thermal runaway can be prevented.
  • the amount of a reducing agent supplied in exhaust gas in the regeneration process can be reduced to a minimum so that the fuel consumption is also improved.
  • the device for detecting the distribution of trapped particulate matter in accordance with the present invention includes a trap case, electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to the trap case, electromagnetic wave receiving means for detecting the intensity of the electromagnetic wave passed through each of a plurality of portions in the trap case, and computing means for computing the amount of trapped particulate matter from the intensity detected with the electromagnetic wave receiving means and computing the distribution of trapped particulate matter in the trap case.
  • the particulate matter in the present invention is not limited specifically, but any material will do provided that it absorbs a microwave on a level of a millimeter wave having a frequency from several tens GHz to several THz, and finally converts absorbed energy to thermal energy.
  • Examples of such material include PM mainly composed of carbon, a magnetic body powder such as a ferrite powder, etc.
  • the microwave on a level of a millimeter wave having a frequency from several tens GHz to several THz is used.
  • the frequency is lower than this range, such a microwave readily passes through the trapped particulate matter to lower the detecting accuracy of the amount of trapped particulate matter.
  • the frequency is higher than this range, such a microwave is difficult to pass through the trapped particulate matter to lower the detecting accuracy.
  • the electromagnetic wave receiving means for detecting the microwave with 100 to 200 GHz can be composed of a low-priced general purpose good with a stable quality.
  • the trap case is disposed in a flow passage for a gas containing particulate matter to trap the same, and various kinds of filters can be used. Cases that transmit the microwave on a level of a millimeter wave having a frequency of several tens GHz to several THz are used as the trap case. One part of the microwave may be absorbed. In the case of the exhaust gas purifying device, filters made of ceramics such as cordierite, silicon carbide, silicon nitride, alumina, etc. are typically used. These ceramics exhibit high transmittance against the microwaves on a level of a millimeter wave having a frequency of several tens GHz to several THz.
  • a filter with catalyst which is provided with oxidation catalyst layers on surfaces of cell partition walls of the filter and surfaces of fine pores inside the cell partition walls.
  • the microwaves are absorbed with noble metals such as Pt, etc. as the catalyst, and where the amount of the supported noble metal and the distribution thereof are constant, the distribution of trapped particulate matter can be detected with a high accuracy.
  • the electromagnetic wave applying means are means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a trap case from an outside thereof, and magnetron, etc. can be used. It is desirable to apply an electromagnetic wave directly to the trap case, but where the trap case is accommodated within a metallic case, like the exhaust gas purifying filter, the electromagnetic wave is applied via an entrance window provided in the case to pass the electromagnetic wave of several tens GHz to several THz.
  • This entrance window can be composed of ceramics such as cordierite, silicon nitride, alumina, etc., glass, etc.
  • the electromagnetic wave receiving means detects the intensity of the electromagnetic wave passed through the trap case, and well known means such as microwave sensors can be used. It is desirable that the electromagnetic wave receiving means is disposed opposite to the electromagnetic wave applying means with respect to the trap case, and close to the trap case. However, in the case of the exhaust gas purifying device, the electromagnetic wave receiving means may be deteriorated due to heat so that it is arranged to receive the electromagnetic wave of several tens GHz to several THz via a radiation window provided in the case to pass such an electromagnetic wave. This radiation window can be composed of the material exhibiting heat-resistance, similarly to that of the entrance window.
  • the electromagnetic wave applying means and the electromagnetic wave receiving means are disposed on opposite sides with respect to the trap case.
  • the trap case having a cylindrical configuration, such as a honeycomb filter
  • they may be disposed on both sides in the radial directions thereof.
  • the method and device for detecting the trap distribution in accordance with the present invention, it is desirable to detect the trap distribution while the trap case that has trapped the particulate matter is disposed in a humidity chamber of which at least the humidity is constant. Since the microwave on a level of a millimeter wave with a frequency of several tens GHz to several THz is absorbed with moisture content, the detected value varies with the variation in the humidity of the measuring atmosphere, and consequently, the detection accuracy is lowered.
  • the electromagnetic wave is applied from a plurality of portions to the trap case, and the intensity of the electromagnetic wave passed through each of the plurality of portions is detected with the electromagnetic wave receiving means.
  • the electromagnetic wave applying means and the electromagnetic wave receiving means can be disposed such that a plurality of these means face each other along a surface of the trap case.
  • the detection may be carried out in a plurality of portions while moving a pair of the electromagnetic wave applying means and the electromagnetic wave receiving means in an axial direction of the trap case or in a radial direction of both end surfaces thereof with the electromagnetic wave applying means and the electromagnetic wave receiving means faced each other.
  • the detection in a plurality of portions by moving the electromagnetic wave applying means and the electromagnetic wave receiving means in an axial direction while turning them along a circumference of the trap case, similarly to CT scanning.
  • the distribution of trapped particulate matter in the trap case can be detected from many angles so as to be displayed as a two-dimensional or three-dimensional picture.
  • the computing means compute the amount of trapped particulate matter from the intensity of the electromagnetic wave, which has been detected with the electromagnetic wave receiving means in the plurality of portions, and compute the distribution of trapped particulate matter in the trap case from the computed results. For example, by substituting the intensity of the electromagnetic wave, which has been detected with the electromagnetic wave receiving means, for a previously determined relational equation between the intensity and the amount of the trapped particulate matter, the amount of trapped particulate matter is computed. By computing the amount of trapped particulate matter in the plurality of portions, the trap distribution can be computed.
  • the trap case itself absorbs the electromagnetic wave with a frequency of several tens GHz to several THz by some amount, and accordingly, first, the intensity received with the trap case that has not trapped the particulate matter is measured as a blank. By doing so, the amount of trapped particulate matter can be computed from the difference between the first measured intensity and the intensity in the trapped state of the particulate matter.
  • the computing means computes the absorption coefficient of the electromagnetic wave ll in the filter that has trapped PM from the detected value with the electromagnetic wave receiving means, and computes the amount of trapped PM from the ratio of the computed absorption coefficient to the previously measured absorption coefficient of the electromagnetic wave in only the filter that has not trapped PM.
  • the absorption coefficient of the electromagnetic wave is expressed by a linear equation regardless of various factors such as temperature, etc. so that the computing of the amount of trapped PM can be carried out readily with a high accuracy.
  • the absorption coefficient is expressed by the logarithm of the transmittance, and the transmittance is the ratio of the radiation output to the incident output.
  • the exhaust gas purifying device in accordance with the present invention, the distribution of trapped PM can be detected with a high accuracy. Therefore, the exhaust gas purifying device can detect that a large amount of PM is trapped locally, etc., and consequently, by carrying out the regeneration process before the amount of trapped PM in that portion exceeds a predetermined level, the filter can be securely prevented from melting away during the regeneration of the filter while restraining the fuel consumption to a minimum.
  • the exhaust gas purifying device in accordance with the present invention further includes means for controlling the temperature of exhaust gas flowing in the filter so as to make it different between the outer periphery and the inner periphery thereof, means for controlling the relationship between an inlet end surface of the filter and the passage through which exhaust gas flow thereto, means for heating a specific portion in an axial direction of the filter, etc.
  • water is also a material that absorbs an electromagnetic wave, and the moisture amount within the filter affects the detected value. Therefore, it is desirable to carry out the detection considering the moisture amount that is detected with a moisture sensor, etc.
  • the saturated water vapor pressure is constant so that the moisture included in exhaust gas can be regarded to be constant, and consequently, the distribution of trapped PM can be detected without exhibiting any practical problem.
  • FIG. 1 is a diagram showing the arrangement of a trap distribution detecting device in one embodiment of the present invention.
  • FIG. 2 is a graph showing the relationship between the amount of trapped PM and the transmittance.
  • FIG. 3 is a graph showing the relationship between the amount of trapped PM and the PM ratio.
  • FIG. 4 is a graph showing the distribution of trapped PM in a direction along a flow passage of the filter, which is detected in one embodiment of the present invention.
  • FIG. 5 is a diagram showing the arrangement of a trap distribution detecting device in a second embodiment of the present invention.
  • FIG. 6 is a graph showing the distribution of trapped PM in a radial direction of the filter, which is detected in the second embodiment of the present invention.
  • FIG. 7 is a block diagram of an exhaust gas purifying device in a third embodiment of the present invention.
  • FIG. 8 is an enlarged sectional view of a main portion of an exhaust gas purifying device in the third embodiment of the present invention.
  • FIG. 1 schematically shows a trap distribution detecting device of the present embodiment.
  • This device includes a filter 1 for use in an exhaust system of a diesel engine, a microwave transmitter 2, a microwave receiver 3 and a computing unit 4.
  • the filter 1 has a wall flow structure having a honeycomb configuration, which includes flow-in side cells, each being plugged at an exhaust gas downstream side thereof, flow-out side cells, each being adjacent to the flow-in side cells and plugged at an exhaust gas upstream side thereof, and porous cell partition walls that partition the flow-in side cells and the flow-out side cells, and have many fine pores, and is composed of cordierite.
  • This filter 1 is disposed on a sample support 10 such that a flow-out side end thereof contact the same. And the sample support 10 is provided with a weight sensor 11 that detects the weight of the filter 1.
  • the microwave transmitter 2 is provided with three routes of transmitting sections 20, 21 and 22, and the transmitting sections 20, 21 and 22 are arranged along a surface of an outer periphery of the filter 1 on a straight line that is in parallel with a central axis of the filter 1.
  • the transmitting sections 20, 21 and 22 respectively apply a millimeter wave with 600 GHz to an inlet-side end of the filter 1 (the transmitting section 20), to an outlet-side end thereof (the transmitting section 22), and to an axial center thereof between the transmitting section 20 and the transmitting section 22 (the transmitting section 21).
  • the microwave receiver 3 is provided with three routes of receiving sections 30, 31 and 32, and the receiving sections 30, 31 and 32 are respectively arranged symmetrically with the transmitting sections 20, 21 and 22 with respect to the central axis of the filter 1 to receive a microwave that has passed through the filter 1.
  • a new filter 1 is placed on the sample support 10, and the weight W B is measured with the weight sensor 11 of the above-described trap distribution detecting device, and a millimeter wave of 600 GHz is applied from each of the transmitting sections 20, 21 and 22 with an input intensity IB. And the output intensities I 0 , h, I 2 of the millimeter waves that have passed through the filter 1 in a radial direction are respectively measured with the receiving sections 30, 31 and 32.
  • the filter 1 Since the filter 1 has not trapped PM, and has an identical cross-sectional construction from one end thereof to the other end thereof, the absorption coefficients c ⁇ r in respective portions: an upstream end portion, a central portion and a downstream end portion thereof become equal to each other. And the transmittances in respective portions (I O /IB, I-I/IB, b/l ⁇ ) also become equal to each other.
  • plural kinds of filters 1 each previously trapping a prescribed amount of PM homogeneously from an upstream side end to a downstream side end thereof, are prepared such that only the amount of trapped PM differs from each other, and the output intensities I 0 , U, b of the millimeter waves that have passed through the filter 1 in a radial direction are respectively measured, similarly to the preceding manner.
  • the transmittances (IO/IB, II/IB, la/l ⁇ ) are the same in the same filter 1 , but differ between plural kinds of filters having different amounts of trapped PM.
  • the relationship between the previously known amount of trapped PM and the measured transmittances (IO/IB, II/IB, b/l ⁇ ) is shown in FIG. 2.
  • the computing unit 4 computes the absorption coefficient ⁇ w (with PM) of the filter 1 that has homogeneously trapped PM from the equation 1. And the PM ratio ( a J a r ) that is the ratio of the above absorption coefficient of the filter 1 to the absorption coefficient ⁇ r of a new filter 1 is computed, and the relationship between the amount of trapped PM and the PM ratio is shown in FIG. 3.
  • a new filter 1 is mounted on an exhaust system of a diesel engine, and after the engine runs by 100 km under a constant running condition of 60 km/hr, the filter 1 is removed as a sample.
  • the filter 1 after used is placed on the sample support 10, the weight Wo is measured with the weight sensor 11 , and a millimeter wave of 600 GHz is applied from each of the transmitting sections 20, 21 and 22 with an input intensity of IB. And output intensities lo, l-i, b of the millimeter waves passed through the filter 1 in a radial direction are respectively measured.
  • the absorption coefficients ( c ⁇ w o, ⁇ wi, ⁇ W 2) in respective portions of the used filter 1 , that is an upstream end portion, a central portion, and a downstream end portion thereof, are computed from the equation 1 , and the PM ratios that are the ratios of the computed absorption coefficients to the absorption coefficient ⁇ r of the new filter 1 are computed, respectively.
  • the amounts of trapped PM, which correspond to the respective PM ratios, are read from the graph of FIG. 3, and the results obtained by correcting them with the weights of trapped PM (W 0 -WB, WI-W B , W 2 -WB) are shown in FIG. 4.
  • the amount of trapped PM is the largest in the upstream end portion of the used filter 1 , and rapidly decreases toward the central portion, whereas in the area from the central portion to the downstream end portion thereof, the amount of trapped PM gently decreases. Namely, according to the method and device for detecting the trap distribution of the present embodiment, the distribution of the amount of trapped PM in the exhaust gas flowing direction can be readily detected with a high accuracy without breaking the used filter 1.
  • the absorption coefficients ⁇ r in respective portions of the used filter 1 that is the upstream end portion, the central portion, and the downstream end portion thereof, are equal to one another, and the transmittances in respective portions (I 0 /IB, MB, b/l ⁇ ) are also equal to one another.
  • the transmittances in respective portions differ from one another, the distribution of the amount of trapped PM can be computed from the difference in amount of trapped PM in the same portion.
  • a filter 1 similar to that of Embodiment 1 was placed on the sample support 10 such that a central axis of the filter 1 becomes parallel to a surface of the sample support 10.
  • the transmitting sections 20, 21 and 22 are arranged so as to face a flow-inlet side end surface of the filter 1 in a radial direction thereof, and respectively apply a millimeter wave of 600 GHz to cells or plugs of an outer peripheral portion (the transmitting sections 20 and 22), and those of an axial center portion (the transmitting section 21).
  • the receiving sections 30, 31 and 32 are arranged so as to face a flow-outlet side end surface of the filter 1 in a radial direction, and are disposed in the portions facing the transmitting sections 20, 21 and 22 to receive microwaves passed through the filter 1.
  • Absorption coefficients ( ⁇ w0 , c ⁇ w i > c ⁇ w2 ) in respective portions of a used filter 1, that is an upper part of an outer peripheral portion, an inner peripheral portion, and a lower part of the outer peripheral portion thereof, are computed, similarly to Embodiment 1 except for the above arrangement, and PM ratios that are the ratios of the absorption coefficients ( ⁇ w o, ⁇ w i, «w2) to the absorption coefficient a r of a new filter 1 are respectively computed.
  • amounts of trapped PM, each corresponding to each of the PM ratios, are read from the graph of FIG. 3, and the results obtained by correcting them with the weights of trapped PM (W 0 -WB, WI-WB, W 2 -W 6 ) are shown in FIG. 6.
  • the amount of trapped PM is large in the upper and lower parts of the outer peripheral portion of the used filter 1 , and is small in the inner peripheral portion thereof. Namely, according to the method and device for detecting the trap distribution of the present embodiment, the distribution of the amount of trapped PM in the radial direction can be readily detected with a high accuracy without breaking the used filter 1.
  • the absorption coefficients a r in respective portions of the filter 1 that has not trapped PM that is the upper part of the outer peripheral portion, the inner peripheral portion, and the lower part of the outer peripheral portion thereof, are equal to one another, and the transmittances in respective portions (I 0 /IB, II/IB, b/l ⁇ ) are also equal to one another.
  • the transmittances in respective portions differ from one another, the distribution of the amount of trapped PM can be computed from the difference in amount of trapped PM in the same portion.
  • FIG. 7 illustrates an exhaust gas purifying device of the present embodiment.
  • the filter 1 ' with a catalyst has a honeycomb-shaped wall flow construction including flow-in side cells plugged on the exhaust gas downstream side thereof, flow-out side cells that are adjacent to the flow-in side cells and plugged on the exhaust gas upstream side thereof, and cell partition walls adapted to partition the flow-in side cells and the flow-out side cells and having many fine pores, and is composed of cordierite, similarly to Embodiment 1.
  • Catalyst layers wherein pt is supported on alumina are formed on surfaces of the cell partition walls and surfaces defining the fine pores.
  • Three transmitting sections 20, 21 and 22, each extending from a microwave transmitter (not shown), and three receiving sections 30, 31 and 32, each extending from a microwave receiver (not shown) are disposed in about a widthwise center of the converter 51 on the outside thereof.
  • the three transmitting sections 20, 21 and 22, and the three receiving sections 30, 31 and 32 are respectively arranged on both sides of the filter 1' with catalyst on a plane including a central axis thereof so as to face each other.
  • the drive of the microwave transmitter is controlled with an ECU 6, and signals received with the microwave receiver are inputted in the ECU 6. As shown in FIG.
  • an entrance window 56 and a radiation window 57 are formed in a surface of the converter 51 so as to face the three transmitting sections 20, 21 and 22 and the three receiving sections 30, 31 and 32.
  • a new filter 1' with catalyst is used, and first, millimeter waves of 600 GHz are transmitted from the three transmitting sections 20, 21 and 22 with an input intensity of IB without driving the engine 5. And output intensities (I 0 , li, b) received with the three receiving sections 30, 31 and 32 are measured. Energy of the transmitted millimeter waves is absorbed with the entrance window 56, the filter V with catalyst, and the radiation window 57 by some amount.
  • the filter 1' with catalyst since the filter 1' with catalyst has not trapped PM, it has the same cross-section from one end to the other end thereof, and the distribution of supported Pt is uniform, the absorption coefficients ⁇ r ⁇ n respective portions, that is an upstream end portion, central portion, and downstream end portion thereof, become equal to one another. And the transmittances in respective portions (IO/IB, II/IB, fe/le) become also equal to one another.
  • the three transmitting sections 20, 21 and 22 are continuously driven while driving the engine 5, and the ECU 6 continuously observes the PM ratios computed from the output intensities received with the three receiving sections 30, 31 and 32. And the amount of trapped PM is computed from the relational equation corresponding to FIG. 3, and where the amount of trapped PM on the flow-in side, which is detected with the receiving section 30, exceeds a predetermined value, the ECU 6 drives the injection nozzle 55 to supply a prescribed amount of light oil in exhaust gas.
  • the light oil supplied in exhaust gas flows in the filter V with catalyst, and ignites to burn even in a low temperature range due to the catalytic action of Pt that is supported on the catalyst layers. With this combustion heat, the filter 1' with catalyst is raised to about 600 0 C or more, and the trapped PM burns. At this time, the ECU 6 continuously observes each PM ratio.
  • the distribution of trapped PM can be readily detected with a high accuracy by measuring the PM ratios.
  • the distribution process of the filter 1' with catalyst can be surely carried out before the amount of trapped PM does not increase excessively so that melting away due to thermal runaway can be prevented.
  • the drive of the injection nozzle 55 can be reduced to a minimum, the fuel consumption is improved.

Abstract

The distribution of trapped particulate matter such as PM, which absorbs electromagnetic waves, is readily detected with a high accuracy by a non-destructive method. The steps of applying an electromagnetic wave with a frequency of several tens GHz to several THz to a trap case which has trapped particulate matter, from an outside thereof, detecting intensity of electromagnetic wave passed through the trap case, and computing the amount of trapped particulate matter by substituting the detected intensity for a prescribed relational equation between intensity of an electromagnetic wave and an amount of trapped particulate matter are carried out in a plurality of portions in the trap case, thereby detecting distribution of trapped particulate matter in the trap case. Since the local variation in the amount of trapped particulate matter can be detected with a high accuracy, the regeneration process can be carried out before the amount of trapped particulate matter does not become too large, and consequently, the amount of a reducing agent, which is supplied in exhaust gas, can be reduced to a minimum in the regeneration process.

Description

DESCRIPTION
METHOD FOR DETECTING DISTRIBUTION OF TRAPPED PARTICULATE MATTER, DEVICE FOR DETECTING DISTRIBUTION OF TRAPPED PARTICULATE MATTERAND EXHAUST GAS PURIFYING DEVICE
TECHNICAL FIELD
[0001] The present invention relates to a method for detecting the distribution of trapped particulate matter, and a device for detecting the distribution of trapped particulate matter. The present invention can be used to detect the distribution of PM accumulated in a filter that is disposed in an exhaust system of a diesel engine, for example.
BACKGROUND ART
[0002] With respect to gasoline engines, harmful components in exhaust gas have been securely reduced by virtue of the stringent exhaust gas regulations and developments in technologies capable of meeting the same. However, with respect to diesel engines, harmful components have been emitted as PM (soot mainly composed of carbon particulates, hydrocarbon particulates with a high molecular weight, sulfur-based particulates such as sulfates, etc.), and under these circumstances, exhaust gas from diesel engines is difficult to be purified, as compared with that from gasoline engines.
[0003] A trap-type exhaust gas purifying device (wall-flow) and an open-type exhaust gas purifying device (straight-flow) are well known as the conventionally developed exhaust gas purifying device for diesel engines. And a plugged type honeycomb body made of ceramic (diesel PM filter) is known as the trap-type exhaust gas purifying device. This filter is prepared by plugging ends of openings of cells of the ceramic honeycomb body alternately in a checkered pattern, for example, and includes flow-in side cells plugged at the exhaust gas downstream side, flow-out side cells that are adjacent to the flow-in side cells and plugged at the exhaust gas upstream side, and cell partition walls adapted to partition the flow-in side cells and the flow-out side cells. This filter filtrates exhaust gas with fine pores of the cell partition walls to trap PM, thereby restraining emission thereof.
[0004] However, the exhaust pressure drop increases in the filter due to the accumulation of PM so that the filter is needed to be regenerated by periodically removing the accumulated PM with some means. Under these circumstances, conventionally, the regeneration process has been carried out by adding a reducing agent such as fuel to exhaust gas, generating ignition in the filter of which the temperature is raised, and burning PM trapped in the filter with resultant combustion heat. In addition, a forced regeneration of the filter has been also carried out by disposing an oxidation catalyst on the upstream side of the filter, generating combustion with the oxidation catalyst to raise the temperature of exhaust gas, and supplying a high temperature exhaust gas to the filter.
[0005] However, where the amount of PM trapped in the filter is locally high, there exhibits the problem that the filter locally melts away due to the heat generation caused by the combustion. In addition, where a large amount of PM is trapped on the upstream side of the filter, exhaust gas is heated excessively due to the combustion heat in that area, and is transmitted to the downstream side of the filter to cause thermal runaway, whereby this area may melt away. On the other hand, if the regeneration process is carried out while the amount of trapped PM is low, the probability of melting of the filter is lowered, but the amount of fuel added increases to worsen the fuel consumption. [0006] Under these circumstances, it can be considered to raise the exhaust gas temperature forcibly when the amount of trapped PM is judged to exceed a predetermined level. In one example of the method for regenerating the filter, a data of the amount of emitted PM relative to the engine operation condition is stored in ECU as a map data, the amount of emitted PM is estimated from an integrated value in the operation time, and the amount of trapped PM is estimated from the cumulating of the estimated amount of emitted PM. And at the time the amount of trapped PM is judged to exceed a predetermined level, the exhaust gas temperature is raised forcibly to regenerate the filter.
[0007] However, where the data of the amount of emitted PM relative to the engine operation condition is used as a map data, there is exhibited the problem that the estimation error becomes large. Alternatively, there has been also used a pressure difference between the upstream side and the downstream side of the filter as an index of the amount of trapped PM. With this method, however, a critical value of the pressure difference as the standard of the judgment greatly varies with the engine operation condition so that the data about the critical pressure difference in each operation condition must be stored as the map data, and consequently, the amount of data becomes too great. Furthermore, the amount of trapped PM is not related to the pressure difference in a straight-line relationship, and there is exhibited the problem that in the range where the amount of trapped PM is small, the detection sensitivity is low.
[0008] Japanese patent application laid-open No. 2005-325771 discloses a method of detecting an electric current or electric voltage, which is generated in a secondary coil wound around an outer periphery of a trap case when an alternating current is passed through a primary coil wound around the outer periphery of the trap case, to compute the amount of trapped PM from the detected electric current or electric voltage. In the secondary coil, an induced electromotive force corresponding to the amount of trapped PM is generated so that the amount of trapped PM can be computed by detecting the electric current or electric voltage, which is generated in the secondary coil.
[0009] Japanese patent application laid-open No. HeM 0-220219 proposes an exhaust gas purifying device with which the amount of PM is detected by measuring the intensity of an electromagnetic wave with a microwave sensor. This technique utilizes that when PM deposits on a filter, the dielectric constant and the dielectric loss of the filter vary, the phase of microwave in the filter shifts, and consequently, the intensity of the microwave varies, and the amount of deposited PM is detected from the variation in the intensity of the microwave by fixing the microwave detecting portion, and measuring the intensity of the microwave in that portion.
[0010] However, there are problems that since the dielectric constant and the dielectric loss of the filter are affected by the temperature thereof, the temperature correction thereof is needed, and that since the electromagnetic field intensity is detected with the microwave sensor, using stationary waves without measuring phase differences directly, it is difficult to separate the influence of the attenuation of the microwave with a one-point measurement so that the detection cannot be carried out with accuracy. Therefore, it is required to carry out a synthetic evaluation by measuring at a plurality of measuring points, or carry out a troublesome evaluation using map data. In addition, the microwave of 2.45 GHz, which is normally used as the microwave, has a wavelength of about 12 cm so that the resolving power is low, and consequently, the local variation in the amount of trapped PM cannot be detected.
[0011] With the above-described methods disclosed in publications, a physical amount related to the average amount of trapped PM or the total amount of trapped PM in the whole of the filter can be detected, but it is difficult to detect the distribution of trapped PM in the filter. In the filter mounted on a vehicle, the amount of accumulated PM at an exhaust gas upstream side thereof, for example, may become larger than that at an exhaust gas downstream side thereof. In addition, the amount of accumulated PM in an outer peripheral part of the filter, from which heat is readily taken away, becomes larger than that in an inner peripheral part thereof. Therefore, even if the average amount of trapped PM or the total amount of trapped PM is detected, the amount of information has been insufficient for accurately judging whether the regeneration process should be carried out or not.
[0012] On the other hand, where the filter that has trapped PM is cut, it is possible to measure the distribution of trapped PM. However, it is desirable to detect the distribution of trapped PM with a non-destructive detection method.
SUMMARY OF THE INVENTION
[0013] The present invention has been made in view of the above-described circumstances, and has the technical problem of readily detecting the distribution of trapped particulate matter that absorbs electromagnetic waves, such as PM, accurately with a non-destructive detecting method.
[0014] A method for detecting the distribution of trapped particulate matter in accordance with the present invention includes the steps of applying an electromagnetic wave with a frequency of several tens GHz to several THz to a trap case that has trapped particulate matter, from an outside thereof, detecting the intensity of the electromagnetic wave passed through the trap case, and substituting the detected intensity for a relational equation between a prescribed intensity of the electromagnetic wave and the amount of trapped particulate matter to compute the amount of trapped particulate matter, and these steps are carried out in a plurality of portions in the trap case, thereby detecting the distribution of trapped particulate matter in the trap case.
[0015] In addition, the device for detecting the distribution of trapped particulate matter in accordance with the present invention includes electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a plurality of portions in a trap case that has trapped particulate matter, from an outside thereof, electromagnetic wave receiving means for detecting the intensity of the electromagnetic wave that has passed through the plurality of portions in the trap case, and computing means for computing the amount of trapped particulate matter from the intensity detected with the electromagnetic wave receiving means and computing the distribution of trapped particulate matter in the trap case.
[0016] And the exhaust gas purifying device in accordance with the present invention includes a filter disposed in an exhaust gas passage for trapping PM mainly composed of carbon, a case for accommodating the filter, electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a plurality of portions in the filter from an entrance window provided in the case, electromagnetic wave receiving means for detecting the intensity of the electromagnetic wave that has passed through the filter and radiated from a radiation window provided in the case, and computing means for computing the distribution of trapped particulate matter from the intensity detected with the electromagnetic wave receiving means.
[0017] With the method for detecting the distribution of trapped particulate matter and the device for detecting the distribution of trapped particulate matter in accordance with the present invention, the amount of trapped particulate matter in each of applied portions of an electromagnetic wave is detected using the electromagnetic wave with a frequency of several tens GHz to several THz (wavelength is on a millimeter level) and utilizing the absorption of the electromagnetic wave with the particulate matter, and the distribution of trapped particulate matter is detected by detecting the amount of trapped particulate matter in each of a plurality of portions so that the distribution of trapped particulate matter in the trap case can be detected with a high accuracy.
[0018] And with the exhaust gas purifying device in accordance with the invention, since the local variation in the amount of trapped PM can be detected with a high accuracy, the regeneration process can be carried out before the amount of trapped PM locally increases too much, whereby the melting of the filter due to the thermal runaway can be prevented. In addition, the amount of a reducing agent supplied in exhaust gas in the regeneration process can be reduced to a minimum so that the fuel consumption is also improved.
[0019] The device for detecting the distribution of trapped particulate matter in accordance with the present invention includes a trap case, electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to the trap case, electromagnetic wave receiving means for detecting the intensity of the electromagnetic wave passed through each of a plurality of portions in the trap case, and computing means for computing the amount of trapped particulate matter from the intensity detected with the electromagnetic wave receiving means and computing the distribution of trapped particulate matter in the trap case.
[0020] The particulate matter in the present invention is not limited specifically, but any material will do provided that it absorbs a microwave on a level of a millimeter wave having a frequency from several tens GHz to several THz, and finally converts absorbed energy to thermal energy. Examples of such material include PM mainly composed of carbon, a magnetic body powder such as a ferrite powder, etc.
[0021] And, with the present invention, the microwave on a level of a millimeter wave having a frequency from several tens GHz to several THz is used. When the frequency is lower than this range, such a microwave readily passes through the trapped particulate matter to lower the detecting accuracy of the amount of trapped particulate matter. When the frequency is higher than this range, such a microwave is difficult to pass through the trapped particulate matter to lower the detecting accuracy. It is desirable to use a microwave with a frequency of about 100 to 600 GHz. In particular, the electromagnetic wave receiving means for detecting the microwave with 100 to 200 GHz can be composed of a low-priced general purpose good with a stable quality.
[0022] The trap case is disposed in a flow passage for a gas containing particulate matter to trap the same, and various kinds of filters can be used. Cases that transmit the microwave on a level of a millimeter wave having a frequency of several tens GHz to several THz are used as the trap case. One part of the microwave may be absorbed. In the case of the exhaust gas purifying device, filters made of ceramics such as cordierite, silicon carbide, silicon nitride, alumina, etc. are typically used. These ceramics exhibit high transmittance against the microwaves on a level of a millimeter wave having a frequency of several tens GHz to several THz.
[0023] It is also preferable to use a filter with catalyst, which is provided with oxidation catalyst layers on surfaces of cell partition walls of the filter and surfaces of fine pores inside the cell partition walls. The microwaves are absorbed with noble metals such as Pt, etc. as the catalyst, and where the amount of the supported noble metal and the distribution thereof are constant, the distribution of trapped particulate matter can be detected with a high accuracy.
[0024] The electromagnetic wave applying means are means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a trap case from an outside thereof, and magnetron, etc. can be used. It is desirable to apply an electromagnetic wave directly to the trap case, but where the trap case is accommodated within a metallic case, like the exhaust gas purifying filter, the electromagnetic wave is applied via an entrance window provided in the case to pass the electromagnetic wave of several tens GHz to several THz. This entrance window can be composed of ceramics such as cordierite, silicon nitride, alumina, etc., glass, etc.
[0025] The electromagnetic wave receiving means detects the intensity of the electromagnetic wave passed through the trap case, and well known means such as microwave sensors can be used. It is desirable that the electromagnetic wave receiving means is disposed opposite to the electromagnetic wave applying means with respect to the trap case, and close to the trap case. However, in the case of the exhaust gas purifying device, the electromagnetic wave receiving means may be deteriorated due to heat so that it is arranged to receive the electromagnetic wave of several tens GHz to several THz via a radiation window provided in the case to pass such an electromagnetic wave. This radiation window can be composed of the material exhibiting heat-resistance, similarly to that of the entrance window.
[0026] The electromagnetic wave applying means and the electromagnetic wave receiving means are disposed on opposite sides with respect to the trap case. For example, in the case of the trap case having a cylindrical configuration, such as a honeycomb filter, they may be disposed on both sides in the radial directions thereof. Alternatively, it is preferable to dispose them at the exhaust gas inlet side and at the exhaust gas outlet side on a plane including an axis of the cylindrical trap case opposite to each other. With these arrangements, the amount of trapped PM can be detected over the entire length in the exhaust gas flowing direction.
[0027] With the method and device for detecting the trap distribution in accordance with the present invention, it is desirable to detect the trap distribution while the trap case that has trapped the particulate matter is disposed in a humidity chamber of which at least the humidity is constant. Since the microwave on a level of a millimeter wave with a frequency of several tens GHz to several THz is absorbed with moisture content, the detected value varies with the variation in the humidity of the measuring atmosphere, and consequently, the detection accuracy is lowered.
[0028] With the method and device for detecting the trap distribution in accordance with the present invention, the electromagnetic wave is applied from a plurality of portions to the trap case, and the intensity of the electromagnetic wave passed through each of the plurality of portions is detected with the electromagnetic wave receiving means. The electromagnetic wave applying means and the electromagnetic wave receiving means can be disposed such that a plurality of these means face each other along a surface of the trap case. Or the detection may be carried out in a plurality of portions while moving a pair of the electromagnetic wave applying means and the electromagnetic wave receiving means in an axial direction of the trap case or in a radial direction of both end surfaces thereof with the electromagnetic wave applying means and the electromagnetic wave receiving means faced each other. Or, it is also preferable to carry out the detection in a plurality of portions by moving the electromagnetic wave applying means and the electromagnetic wave receiving means in an axial direction while turning them along a circumference of the trap case, similarly to CT scanning. With these arrangements, the distribution of trapped particulate matter in the trap case can be detected from many angles so as to be displayed as a two-dimensional or three-dimensional picture.
[0029] With respect to the plurality of portions, in the case of a trap case having a cylindrical configuration, such as a honeycomb filter, for example, it is preferable to arrange them in the axial direction thereof, and it is also preferable to arrange them along a diameter of each of end surfaces thereof.
[0030] The computing means compute the amount of trapped particulate matter from the intensity of the electromagnetic wave, which has been detected with the electromagnetic wave receiving means in the plurality of portions, and compute the distribution of trapped particulate matter in the trap case from the computed results. For example, by substituting the intensity of the electromagnetic wave, which has been detected with the electromagnetic wave receiving means, for a previously determined relational equation between the intensity and the amount of the trapped particulate matter, the amount of trapped particulate matter is computed. By computing the amount of trapped particulate matter in the plurality of portions, the trap distribution can be computed.
[0031] In many cases, the trap case itself absorbs the electromagnetic wave with a frequency of several tens GHz to several THz by some amount, and accordingly, first, the intensity received with the trap case that has not trapped the particulate matter is measured as a blank. By doing so, the amount of trapped particulate matter can be computed from the difference between the first measured intensity and the intensity in the trapped state of the particulate matter.
[0032] In the case of the exhaust gas purifying device, it is desirable that the computing means computes the absorption coefficient of the electromagnetic wave ll in the filter that has trapped PM from the detected value with the electromagnetic wave receiving means, and computes the amount of trapped PM from the ratio of the computed absorption coefficient to the previously measured absorption coefficient of the electromagnetic wave in only the filter that has not trapped PM. By using the absorption coefficient of the electromagnetic wave as an index, the relationship between the amount of trapped PM and the absorption coefficient is expressed by a linear equation regardless of various factors such as temperature, etc. so that the computing of the amount of trapped PM can be carried out readily with a high accuracy. The absorption coefficient is expressed by the logarithm of the transmittance, and the transmittance is the ratio of the radiation output to the incident output.
[0033] With the exhaust gas purifying device in accordance with the present invention, the distribution of trapped PM can be detected with a high accuracy. Therefore, the exhaust gas purifying device can detect that a large amount of PM is trapped locally, etc., and consequently, by carrying out the regeneration process before the amount of trapped PM in that portion exceeds a predetermined level, the filter can be securely prevented from melting away during the regeneration of the filter while restraining the fuel consumption to a minimum.
[0034] It is preferable that the exhaust gas purifying device in accordance with the present invention further includes means for controlling the temperature of exhaust gas flowing in the filter so as to make it different between the outer periphery and the inner periphery thereof, means for controlling the relationship between an inlet end surface of the filter and the passage through which exhaust gas flow thereto, means for heating a specific portion in an axial direction of the filter, etc. By using these means, according to the distribution of trapped PM, only the portions of the filter, in which the amount of trapped PM is great, can be heated locally, and consequently, the regeneration time of the filter can be shortened, and the starting time of the regeneration process can be delayed. Therefore, the fuel consumption can be further reduced.
[0035] As described above, water is also a material that absorbs an electromagnetic wave, and the moisture amount within the filter affects the detected value. Therefore, it is desirable to carry out the detection considering the moisture amount that is detected with a moisture sensor, etc. However, where the detection is carried out while the temperature of the filter is adjusted constant, the saturated water vapor pressure is constant so that the moisture included in exhaust gas can be regarded to be constant, and consequently, the distribution of trapped PM can be detected without exhibiting any practical problem.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a diagram showing the arrangement of a trap distribution detecting device in one embodiment of the present invention.
[0037] FIG. 2 is a graph showing the relationship between the amount of trapped PM and the transmittance.
[0038] FIG. 3 is a graph showing the relationship between the amount of trapped PM and the PM ratio.
[0039] FIG. 4 is a graph showing the distribution of trapped PM in a direction along a flow passage of the filter, which is detected in one embodiment of the present invention.
[0040] FIG. 5 is a diagram showing the arrangement of a trap distribution detecting device in a second embodiment of the present invention. [0041] FIG. 6 is a graph showing the distribution of trapped PM in a radial direction of the filter, which is detected in the second embodiment of the present invention.
[0042] FIG. 7 is a block diagram of an exhaust gas purifying device in a third embodiment of the present invention.
[0043] FIG. 8 is an enlarged sectional view of a main portion of an exhaust gas purifying device in the third embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0044] Hereinafter, embodiments of the present invention will be explained specifically.
[0045] (Embodiment 1)
FIG. 1 schematically shows a trap distribution detecting device of the present embodiment. This device includes a filter 1 for use in an exhaust system of a diesel engine, a microwave transmitter 2, a microwave receiver 3 and a computing unit 4.
[0046]The filter 1 has a wall flow structure having a honeycomb configuration, which includes flow-in side cells, each being plugged at an exhaust gas downstream side thereof, flow-out side cells, each being adjacent to the flow-in side cells and plugged at an exhaust gas upstream side thereof, and porous cell partition walls that partition the flow-in side cells and the flow-out side cells, and have many fine pores, and is composed of cordierite.
[0047] This filter 1 is disposed on a sample support 10 such that a flow-out side end thereof contact the same. And the sample support 10 is provided with a weight sensor 11 that detects the weight of the filter 1.
[0048] The microwave transmitter 2 is provided with three routes of transmitting sections 20, 21 and 22, and the transmitting sections 20, 21 and 22 are arranged along a surface of an outer periphery of the filter 1 on a straight line that is in parallel with a central axis of the filter 1. The transmitting sections 20, 21 and 22 respectively apply a millimeter wave with 600 GHz to an inlet-side end of the filter 1 (the transmitting section 20), to an outlet-side end thereof (the transmitting section 22), and to an axial center thereof between the transmitting section 20 and the transmitting section 22 (the transmitting section 21).
[0049] The microwave receiver 3 is provided with three routes of receiving sections 30, 31 and 32, and the receiving sections 30, 31 and 32 are respectively arranged symmetrically with the transmitting sections 20, 21 and 22 with respect to the central axis of the filter 1 to receive a microwave that has passed through the filter 1.
[0050] By using the above-described trap distribution detecting device, first, a new filter 1 is placed on the sample support 10, and the weight WB is measured with the weight sensor 11 of the above-described trap distribution detecting device, and a millimeter wave of 600 GHz is applied from each of the transmitting sections 20, 21 and 22 with an input intensity IB. And the output intensities I0, h, I2 of the millimeter waves that have passed through the filter 1 in a radial direction are respectively measured with the receiving sections 30, 31 and 32.
[0051] And the absorption coefficient a r (reference) of the new filter 1 that has not trapped PM is computed from the equation 1. [0052] Equation 1
Absorption coefficient a r = -IΠOO/IB)
= -In(li/IB)
=-ln(l2/lB)
[0053] Since the filter 1 has not trapped PM, and has an identical cross-sectional construction from one end thereof to the other end thereof, the absorption coefficients cκ r in respective portions: an upstream end portion, a central portion and a downstream end portion thereof become equal to each other. And the transmittances in respective portions (IO/IB, I-I/IB, b/lβ) also become equal to each other.
[0054] Next, plural kinds of filters 1 , each previously trapping a prescribed amount of PM homogeneously from an upstream side end to a downstream side end thereof, are prepared such that only the amount of trapped PM differs from each other, and the output intensities I0, U, b of the millimeter waves that have passed through the filter 1 in a radial direction are respectively measured, similarly to the preceding manner. The transmittances (IO/IB, II/IB, la/lβ) are the same in the same filter 1 , but differ between plural kinds of filters having different amounts of trapped PM. The relationship between the previously known amount of trapped PM and the measured transmittances (IO/IB, II/IB, b/lβ) is shown in FIG. 2.
[0055] As is apparent from FIG. 2, the relationship between the amount of trapped PM and the transmittance is not expressed by a linear equation. Therefore, in order to estimate the amount of trapped PM from the transmittance, complicated calculations are required.
[0056] The computing unit 4 computes the absorption coefficient αw (with PM) of the filter 1 that has homogeneously trapped PM from the equation 1. And the PM ratio ( a J a r) that is the ratio of the above absorption coefficient of the filter 1 to the absorption coefficient α r of a new filter 1 is computed, and the relationship between the amount of trapped PM and the PM ratio is shown in FIG. 3.
[0057] It is clear from FIG. 3 that the relationship between the amount of trapped PM and the PM ratio is expressed by a linear equation, and it is also known that by measuring the PM ratio, the amount of trapped PM can be readily detected with a high accuracy.
[0058] A new filter 1 is mounted on an exhaust system of a diesel engine, and after the engine runs by 100 km under a constant running condition of 60 km/hr, the filter 1 is removed as a sample. The filter 1 after used is placed on the sample support 10, the weight Wo is measured with the weight sensor 11 , and a millimeter wave of 600 GHz is applied from each of the transmitting sections 20, 21 and 22 with an input intensity of IB. And output intensities lo, l-i, b of the millimeter waves passed through the filter 1 in a radial direction are respectively measured.
[0059] And in the computing unit 4, the absorption coefficients ( cκwo, αwi, αW2) in respective portions of the used filter 1 , that is an upstream end portion, a central portion, and a downstream end portion thereof, are computed from the equation 1 , and the PM ratios that are the ratios of the computed absorption coefficients to the absorption coefficient α r of the new filter 1 are computed, respectively. And the amounts of trapped PM, which correspond to the respective PM ratios, are read from the graph of FIG. 3, and the results obtained by correcting them with the weights of trapped PM (W0-WB, WI-WB, W2-WB) are shown in FIG. 4.
[0060] It is known from FIG. 4 that the amount of trapped PM is the largest in the upstream end portion of the used filter 1 , and rapidly decreases toward the central portion, whereas in the area from the central portion to the downstream end portion thereof, the amount of trapped PM gently decreases. Namely, according to the method and device for detecting the trap distribution of the present embodiment, the distribution of the amount of trapped PM in the exhaust gas flowing direction can be readily detected with a high accuracy without breaking the used filter 1.
[0061] In the present embodiment, the absorption coefficients α r in respective portions of the used filter 1 , that is the upstream end portion, the central portion, and the downstream end portion thereof, are equal to one another, and the transmittances in respective portions (I0/IB, MB, b/lβ) are also equal to one another. However, even where the transmittances in respective portions differ from one another, the distribution of the amount of trapped PM can be computed from the difference in amount of trapped PM in the same portion.
[0062] (Embodiment 2)
In the present embodiment, as shown in FIG. 5, a filter 1 similar to that of Embodiment 1 was placed on the sample support 10 such that a central axis of the filter 1 becomes parallel to a surface of the sample support 10. And the transmitting sections 20, 21 and 22 are arranged so as to face a flow-inlet side end surface of the filter 1 in a radial direction thereof, and respectively apply a millimeter wave of 600 GHz to cells or plugs of an outer peripheral portion (the transmitting sections 20 and 22), and those of an axial center portion (the transmitting section 21). The receiving sections 30, 31 and 32 are arranged so as to face a flow-outlet side end surface of the filter 1 in a radial direction, and are disposed in the portions facing the transmitting sections 20, 21 and 22 to receive microwaves passed through the filter 1.
[0063] Absorption coefficients ( αw0, cκwi> cκw2) in respective portions of a used filter 1, that is an upper part of an outer peripheral portion, an inner peripheral portion, and a lower part of the outer peripheral portion thereof, are computed, similarly to Embodiment 1 except for the above arrangement, and PM ratios that are the ratios of the absorption coefficients ( αwo, αwi, «w2) to the absorption coefficient a r of a new filter 1 are respectively computed. And amounts of trapped PM, each corresponding to each of the PM ratios, are read from the graph of FIG. 3, and the results obtained by correcting them with the weights of trapped PM (W0-WB, WI-WB, W2-W6) are shown in FIG. 6.
[0064] It is known from FIG. 6 that the amount of trapped PM is large in the upper and lower parts of the outer peripheral portion of the used filter 1 , and is small in the inner peripheral portion thereof. Namely, according to the method and device for detecting the trap distribution of the present embodiment, the distribution of the amount of trapped PM in the radial direction can be readily detected with a high accuracy without breaking the used filter 1.
[0065] In the present embodiment, the absorption coefficients a r in respective portions of the filter 1 that has not trapped PM, that is the upper part of the outer peripheral portion, the inner peripheral portion, and the lower part of the outer peripheral portion thereof, are equal to one another, and the transmittances in respective portions (I0/IB, II/IB, b/lβ) are also equal to one another. However, even where the transmittances in respective portions differ from one another, the distribution of the amount of trapped PM can be computed from the difference in amount of trapped PM in the same portion.
[0066] (Embodiment 3)
FIG. 7 illustrates an exhaust gas purifying device of the present embodiment. A converter 51 made of steel, which accommodates a filter 1' having a cylindrical configuration and provided with a catalyst, is interconnected with an exhaust manifold 50 of a diesel engine 5. Most part of the exhaust gas emitted from the exhaust manifold 50 flows inside the converter 51 , passes through the filter 1 and is exhausted, whereas one part of the exhaust gas is returned to an intake manifold 54 of the diesel engine 5 via a turbocharger 52 and an intercooler 53. And an injection nozzle 55 is disposed in the exhaust manifold 50 and is arranged to inject light oil into the exhaust gas intermittently.
[0067] The filter 1 ' with a catalyst has a honeycomb-shaped wall flow construction including flow-in side cells plugged on the exhaust gas downstream side thereof, flow-out side cells that are adjacent to the flow-in side cells and plugged on the exhaust gas upstream side thereof, and cell partition walls adapted to partition the flow-in side cells and the flow-out side cells and having many fine pores, and is composed of cordierite, similarly to Embodiment 1. Catalyst layers wherein pt is supported on alumina are formed on surfaces of the cell partition walls and surfaces defining the fine pores.
[0068] Three transmitting sections 20, 21 and 22, each extending from a microwave transmitter (not shown), and three receiving sections 30, 31 and 32, each extending from a microwave receiver (not shown) are disposed in about a widthwise center of the converter 51 on the outside thereof. The three transmitting sections 20, 21 and 22, and the three receiving sections 30, 31 and 32 are respectively arranged on both sides of the filter 1' with catalyst on a plane including a central axis thereof so as to face each other. The drive of the microwave transmitter is controlled with an ECU 6, and signals received with the microwave receiver are inputted in the ECU 6. As shown in FIG. 8, an entrance window 56 and a radiation window 57, each being composed of alumina and being capable of transmitting microwaves, are formed in a surface of the converter 51 so as to face the three transmitting sections 20, 21 and 22 and the three receiving sections 30, 31 and 32. [0069] In this exhaust gas purifying device, a new filter 1' with catalyst is used, and first, millimeter waves of 600 GHz are transmitted from the three transmitting sections 20, 21 and 22 with an input intensity of IB without driving the engine 5. And output intensities (I0, li, b) received with the three receiving sections 30, 31 and 32 are measured. Energy of the transmitted millimeter waves is absorbed with the entrance window 56, the filter V with catalyst, and the radiation window 57 by some amount. However, since the filter 1' with catalyst has not trapped PM, it has the same cross-section from one end to the other end thereof, and the distribution of supported Pt is uniform, the absorption coefficients α r ιn respective portions, that is an upstream end portion, central portion, and downstream end portion thereof, become equal to one another. And the transmittances in respective portions (IO/IB, II/IB, fe/le) become also equal to one another.
[0070] And the absorption coefficient a r of only the filter 1' with catalyst is computed from the equation 1.
[0071] In the present embodiment, the three transmitting sections 20, 21 and 22 are continuously driven while driving the engine 5, and the ECU 6 continuously observes the PM ratios computed from the output intensities received with the three receiving sections 30, 31 and 32. And the amount of trapped PM is computed from the relational equation corresponding to FIG. 3, and where the amount of trapped PM on the flow-in side, which is detected with the receiving section 30, exceeds a predetermined value, the ECU 6 drives the injection nozzle 55 to supply a prescribed amount of light oil in exhaust gas.
[0072] The light oil supplied in exhaust gas flows in the filter V with catalyst, and ignites to burn even in a low temperature range due to the catalytic action of Pt that is supported on the catalyst layers. With this combustion heat, the filter 1' with catalyst is raised to about 600 0C or more, and the trapped PM burns. At this time, the ECU 6 continuously observes each PM ratio. And light oil is continuously added until at least the amount of trapped PM on the flow-in side out of those on the flow-in side, the central portion and the flow-out side decreases to a predetermined value or less, and when at least the amount of trapped PM on the flow-in side decreases to a predetermined value or less, the ECU 6 stops driving the injection nozzle 55 to prevent melting away of the filter V with catalyst or grain growth of Pt.
[0073] Namely, with the exhaust gas purifying device of the present embodiment, the distribution of trapped PM can be readily detected with a high accuracy by measuring the PM ratios. In addition, by using microwaves on a level of millimeter waves, local variations in the amount of trapped PM can be detected with accuracy. Therefore, the regeneration process of the filter 1' with catalyst can be surely carried out before the amount of trapped PM does not increase excessively so that melting away due to thermal runaway can be prevented. In addition, since the drive of the injection nozzle 55 can be reduced to a minimum, the fuel consumption is improved.
[0074] In the present embodiment, explanations have been made about the cases where the absorption coefficients a r in respective portions of the filter 1 ' with catalyst, which has not trapped PM, that is the upstream end portion, central portion, and downstream end portion thereof, are equal to one another, and the transmittances in respective portions (I0/IB, MB, b/lβ) are also equal to one another. However, even where the transmittances in respective portions differ from each other, the distribution of the amount of trapped PM can be computed from the difference in amount of trapped PM in the same portion.

Claims

1. A method for detecting distribution of trapped particulate matter, comprising the steps of: applying an electromagnetic wave with a frequency of several tens GHz to several THz to a trap case that has trapped particulate matter, from an outside thereof; detecting intensity of the electromagnetic wave that has passed through said trap case; and computing an amount of trapped particulate matter by substituting the detected intensity for a prescribed relational equation between intensity of an electromagnetic wave and an amount of trapped particulate matter, said applying step, said detecting step and said computing step being carried out in a plurality of portions of said trap case, thereby detecting distribution of particulate matter trapped in said trap case.
2. A device for detecting distribution of trapped particulate matter, comprising: electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to each of a plurality of portions in a trap case that has trapped particulate matter, from an outside thereof; electromagnetic wave receiving means for detecting intensity of the electromagnetic wave that has passed through each of said plurality of portions in said trap case; and computing means for computing an amount of trapped particulate matter from the intensity detected with said electromagnetic wave receiving means to compute distribution of trapped particulate matter in said trap case.
3. An exhaust gas purifying device comprising: a filter disposed in an exhaust gas passage for trapping PM mainly composed of carbon; a case for accommodating said filter; electromagnetic wave applying means for applying an electromagnetic wave with a frequency of several tens GHz to several THz to a plurality of portions in said filter from an entrance window provided in said case; and electromagnetic wave receiving means for detecting intensity of the electromagnetic wave that has passed through said filter and radiated from a radiation window provided in said case; and computing means for computing distribution of trapped PM from the intensity detected with said electromagnetic wave receiving means.
4. An exhaust gas purifying device as claimed in claim 3, wherein said computing means computes an absorption coefficient of the electromagnetic wave in said filter that has trapped PM, from the intensity detected with said electromagnetic wave receiving means, and computes an amount of trapped PM based on a ratio of the computed absorption coefficient to a previously measured absorption coefficient of an electromagnetic wave in a filter that has not trapped PM.
PCT/JP2008/065928 2007-09-03 2008-08-28 Method for detecting distribution of trapped particulate matter, device for detecting distribution of trapped particulate matter and exhaust gas purifying device WO2009031600A2 (en)

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Publication number Priority date Publication date Assignee Title
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WO2011055127A1 (en) * 2009-11-06 2011-05-12 Seratel Limited A system and method for analysing exhaust gas
US8161807B2 (en) 2009-03-25 2012-04-24 Ngk Insulators, Ltd. Devices for detecting accumulation amount of particulates
US8210035B2 (en) 2009-10-28 2012-07-03 Advantest Corporation Collection medium and collection amount measuring apparatus, and measuring method, program, and recording medium of the same
US8210033B2 (en) 2009-03-25 2012-07-03 Ngk Insulators, Ltd. Devices for detecting accumulation amount of particulates
US8225684B2 (en) 2010-03-24 2012-07-24 Ngk Insulators, Ltd. Methods for detecting particulates in a honeycomb filter
US20130000274A1 (en) * 2011-06-29 2013-01-03 Caterpillar Inc. Regeneration Control System For Exhaust Filter And Method
US8833063B2 (en) 2011-05-17 2014-09-16 Caterpillar Inc. Methods and system for ash detection in exhaust particulate filter
US8942887B2 (en) 2010-12-16 2015-01-27 Caterpillar Inc. Machine, exhaust particulate filter system, and method
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US10850221B2 (en) 2016-07-08 2020-12-01 Fujitsu Limited Fine particle detector and exhaust gas purification apparatus
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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0097416A1 (en) * 1982-06-21 1984-01-04 General Motors Corporation Microwave detection of soot content in a particulate trap
WO1992002807A1 (en) * 1990-08-03 1992-02-20 Atomic Energy Of Canada Limited Method and apparatus for detecting soot concentration in particulate trap
EP0608752A1 (en) * 1993-01-20 1994-08-03 Matsushita Electric Industrial Co., Ltd. Filter regenerating apparatus for an internal combustion engine
EP0675267A1 (en) * 1994-04-01 1995-10-04 Matsushita Electric Industrial Co., Ltd. Exhaust-gas purifier
DE19827358A1 (en) * 1998-06-19 1999-12-30 Brach Berthold Soot particle sensor, e.g. for investigating diesel engine operation
US20070024289A1 (en) * 2005-07-26 2007-02-01 Caterpillar Inc. Radio frequency particulate sensing system

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2780507B2 (en) * 1991-03-29 1998-07-30 松下電器産業株式会社 Filter regeneration device for internal combustion engine
JPH081128B2 (en) * 1992-02-03 1996-01-10 株式会社リケン Diesel exhaust filter particulate matter trapping amount distribution detection method and device
JPH1183758A (en) * 1997-09-09 1999-03-26 Toshiba Joho Seigyo Syst Kk Densitometer
JP3925225B2 (en) * 2001-03-28 2007-06-06 株式会社デンソー Exhaust gas purification filter and manufacturing method thereof
JP4473522B2 (en) * 2003-05-20 2010-06-02 日本碍子株式会社 Plugged honeycomb structure
JP4385850B2 (en) * 2004-05-14 2009-12-16 いすゞ自動車株式会社 Collection amount detection method and collection amount detection device
JP2007199044A (en) * 2006-01-24 2007-08-09 Junichi Nishizawa Terahertz wave type measuring apparatus and method

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0097416A1 (en) * 1982-06-21 1984-01-04 General Motors Corporation Microwave detection of soot content in a particulate trap
WO1992002807A1 (en) * 1990-08-03 1992-02-20 Atomic Energy Of Canada Limited Method and apparatus for detecting soot concentration in particulate trap
EP0608752A1 (en) * 1993-01-20 1994-08-03 Matsushita Electric Industrial Co., Ltd. Filter regenerating apparatus for an internal combustion engine
EP0675267A1 (en) * 1994-04-01 1995-10-04 Matsushita Electric Industrial Co., Ltd. Exhaust-gas purifier
DE19827358A1 (en) * 1998-06-19 1999-12-30 Brach Berthold Soot particle sensor, e.g. for investigating diesel engine operation
US20070024289A1 (en) * 2005-07-26 2007-02-01 Caterpillar Inc. Radio frequency particulate sensing system

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US8225684B2 (en) 2010-03-24 2012-07-24 Ngk Insulators, Ltd. Methods for detecting particulates in a honeycomb filter
US8942887B2 (en) 2010-12-16 2015-01-27 Caterpillar Inc. Machine, exhaust particulate filter system, and method
US8833063B2 (en) 2011-05-17 2014-09-16 Caterpillar Inc. Methods and system for ash detection in exhaust particulate filter
US8875496B2 (en) 2011-06-29 2014-11-04 Caterpillar Inc. Regeneration control system for exhaust filter and method
US20130000274A1 (en) * 2011-06-29 2013-01-03 Caterpillar Inc. Regeneration Control System For Exhaust Filter And Method
US20140298775A1 (en) * 2011-06-29 2014-10-09 Caterpillar Inc. Regeneration Control System For Exhaust Filter And Method
US11255799B2 (en) 2014-06-06 2022-02-22 Cts Corporation Radio frequency state variable measurement system and method
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