JP5941575B2 - Particle detection system - Google Patents

Description

  The present invention relates to a fine particle detection system that detects the amount of fine particles in a gas to be measured flowing in a ventilation pipe.

Sometimes you want to measure the amount of particulates in a gas. For example, in an internal combustion engine (for example, a diesel engine or a gasoline engine), fine particles such as soot may be contained in the exhaust gas.
Exhaust gas containing such fine particles is purified by collecting the fine particles with a filter. However, when a problem such as breakage of the filter occurs, unpurified exhaust gas is directly discharged downstream of the filter.
Accordingly, there is a need for a particulate detection system that can directly measure the amount of particulates in exhaust gas and detect the amount of particulates in exhaust gas downstream of the filter in order to detect filter malfunctions.

For example, Patent Document 1 discloses a particle measurement processing method and apparatus. In Patent Document 1, gas containing ionized positive ion particles is mixed with exhaust gas containing fine particles taken into the channel from the exhaust pipe to charge the fine particles, and then discharged to the exhaust pipe. And the method of detecting the electric current (signal current) which flows according to the quantity of discharged | emitted charged fine particles and detecting the density | concentration of fine particles is disclosed.
In such a particle detection system, a detection unit that detects the amount of particles generally includes a plurality of conductive members having different potentials and an insulating member that insulates them.

WO2009 / 109688

  However, foreign substances contained in the gas to be measured (for example, soot and water droplets when the gas to be measured is exhaust gas of an internal combustion engine) may adhere to these members. In addition, outside the vent pipe, water droplets may adhere due to foreign matter (soot etc.) contained in the outside air or water. When such a foreign substance adheres to the surface of the insulating member and the insulating property of the insulating member is lowered, even if the detection unit is driven by the drive circuit, the amount of fine particles cannot be detected properly by the detection unit. There is a risk that the drive circuit will break down.

  The present invention has been made in view of such problems, and provides a fine particle detection system that performs detection when the amount of fine particles can be detected appropriately.

One aspect of the present invention for solving the above-described problems is a particulate detection system for detecting the amount of particulates in a gas to be measured flowing in a ventilation pipe, and a detection unit attached to an attachment opening of the ventilation pipe; A drive circuit that drives the detection unit; and a drive control unit that controls the drive circuit. The detection unit is set to a first potential in a state where the detection unit is driven by the drive circuit. A first potential member, a second potential member having a second potential different from the first potential in a state in which the detection unit is driven by the drive circuit, and the first potential member and the second potential member. Between the first potential member and the second potential member to inspect the insulation between the first potential member and the insulating member. The above due to the adhesion of foreign matter in the measured gas Comprising insulating checking means for detecting a decrease in the insulating edge member, and the drive control unit, the height of the insulating examined in the insulating checking means, whether the drive of the detection unit by the drive circuit This is a particulate detection system having a drive availability determination means for determining

In this particulate detection system, the detection unit includes a first potential member that is a first potential, a second potential member that is a second potential, and an insulating member that insulates them.
Further, the insulation between the first potential member and the second potential member is inspected by the insulative inspection means, and whether or not the detection circuit can be driven by the drive circuit according to the level of insulation inspected by the drive availability determination means. Judging. Thereby, in the state where the insulation between the 1st potential member and the 2nd potential member is high, the detection part can be driven and the amount of particulates can be detected, and the amount of particulates can be detected appropriately. In addition, it is possible to prevent a failure of the drive circuit or the like caused by driving the drive circuit in a state of low insulation.

First potential member, a second potential member and the insulating member is Ru exposed to the measurement gas.
Insulation inspection means for inspecting insulation includes applying a test voltage between the first potential member and the second potential member to cause leakage current flowing between them (insulating member) or insulation between them. One that inspects the magnitude of the resistance. In addition, there is one that inspects the capacitance generated between the first potential member and the second potential member using a capacitance meter or the like.
Whether the insulating property is high (low) may be determined according to the outside air temperature, humidity, gas temperature to be measured, or by comparing with a predetermined fixed insulating reference value.
As the insulation reference value, for example, a reference value of leakage current, a reference value of insulation resistance, a reference value of capacitance, or the like can be used according to an insulation inspection method.

  Furthermore, in the fine particle detection system described above, the drive control unit includes a drive stop unit that stops the drive of the detection unit by the drive circuit when the insulation tested by the insulation test unit is low. A fine particle detection system is recommended.

  In this system, when the inspected insulation is low, the drive of the detection unit by the drive circuit is stopped. As a result, when the insulation is low, particularly when the insulation is extremely low (short circuit state), it is possible to reliably prevent problems such as failure of the drive circuit itself or the detection unit due to driving of the drive circuit.

  Furthermore, in the fine particle detection system described above, the insulation inspection unit applies a test voltage between the first potential member and the second potential member, and a leakage current flowing between them or between them A fine particle detection system which is a first inspection means for inspecting the magnitude of the insulation resistance may be used.

In this system, an inspection voltage is applied between the first potential member and the second potential member, and the first potential member and the second potential member are determined according to the leakage current flowing between them or the magnitude of the insulation resistance between them. Check the insulation between the two.
In this method, an inspection voltage may be applied between the first potential member and the second potential member to detect current or resistance, and the level of insulation can be easily inspected.

  Furthermore, in any one of the fine particle detection systems described above, the detection unit includes a first discharge electrode and a second discharge electrode, and an ion source that generates ions by an air discharge between them, the ion source A part of the gas to be measured that is conducted to the first discharge electrode and flows through the vent tube is mixed with the ions generated by the ion source, and the fine particles in the part of the gas to be measured are mixed. The charged fine particles to which the ions are attached are configured to be returned to the vent tube, and the fine particle charging unit that forms a collecting electrode for collecting floating ions that are not attached to the fine particles among the ions, the first discharge electrode, and the A first conducting member that conducts to the fine particle charging unit; a second discharge electrode conducting member that conducts to the second discharge electrode; and the second potential member that contacts and conducts to the vent pipe to form the second potential. Is grounded The first discharge electrode of the ion source, the fine particle charging unit, and the first conduction member are the first potential member that is set to the first potential. The insulating member is interposed between the first potential member and the vent pipe or the ground potential member, and the drive circuit is configured to pass the ion source through the first conduction member when the detection unit is driven. When the first discharge electrode and the fine particle charging unit are energized and the detection unit is driven, the first output terminal is set to the first potential, and the detection unit is driven through the second discharge electrode conducting member. An ion source drive for driving the ion source and the fine particle charging unit, including a second output terminal configured to energize the second discharge electrode and set the second discharge potential to generate a second discharge potential between the second discharge electrode and the first discharge electrode. Circuit, and can be driven Judgment means includes the ion source and the fine particles by the ion source driving circuit according to the level of the insulation between the first potential member, the vent pipe and the ground potential member, which are inspected by the insulation inspection means. A fine particle detection system for determining whether or not the charging unit can be driven is preferable.

  This system has a fine particle charging unit, and the amount of fine particles can be detected based on the amount of electric charge attached to the charged fine particles returned to the vent pipe. That is, the magnitude of the signal current flowing between the first potential, which is the potential of the fine particle charging portion, and the ground potential of the ventilation tube corresponds to the amount of charge discharged from the fine particle charging portion. However, here, if the insulation between the first conducting member set to the first potential and the vent pipe or the ground potential member set to the ground potential is low, it becomes difficult to detect this signal current, The amount of fine particles cannot be detected properly.

  On the other hand, in this system, the insulation test means conducts to the first discharge electrode and the fine particle charging portion of the ion source, and conducts to the first conduction member as the first potential member, the vent pipe, and the second. Insulation with the ground potential member, which is a potential member and is set to ground potential, is inspected. The drive availability determination unit determines whether or not the ion source and the fine particle charging unit can be driven by the ion source drive circuit based on whether the insulation between them is high or low. Thereby, the amount of fine particles can be detected appropriately, and failure of the ion source drive circuit can be prevented.

  In addition, as a format of the air discharge performed with an ion source, corona discharge is mentioned, for example. Moreover, as an arrangement form of the discharge electrodes, even if two electrodes are arranged to face each other and an air discharge is caused between them, two electrodes are arranged adjacent to each other on the substrate. A creeping discharge (in the air) may be generated.

  Furthermore, in the fine particle detection system described above, a first switch interposed between the first output end and the first conducting member to open and close the conduction between the two, the second output end and the first A second switch that opens and closes the conduction between the two discharge electrode conducting members, and a driving switch closing instruction that closes the first switch and the second switch when the detection unit is driven. And an inspection for opening the first switch and the second switch when the insulation between the first potential member and the vent pipe and the ground potential member is inspected by the means and the insulation inspection means. It is preferable that the particulate detection system includes an hour switch opening instruction means.

  In this system, a first switch is provided between the first output end and the first conducting member, and a second switch is provided between the second output end and the second discharge electrode conducting member. Since these are closed when the detection unit is driven, the detection unit (ion source, fine particle charging unit) can be driven by the ion source drive circuit. On the other hand, when inspecting the insulation between the first potential member and the vent pipe and the ground potential member, the first and second switches are opened. Thereby, since the ion source driving circuit is disconnected, the ion source driving circuit can be protected from the inspection voltage applied when inspecting the insulation, and the first potential member and the ion source driving circuit are not affected by the ion source driving circuit. It is possible to appropriately inspect the insulation between the vent pipe and the ground potential member.

  Furthermore, in any one of the above-described fine particle detection systems, the detection unit includes a first discharge electrode and a second discharge electrode, and an ion source that generates ions by an air discharge therebetween, the ion source A portion of the gas to be measured that is conducted to the first discharge electrode and flows through the vent tube is mixed with the ions generated by the ion source, and the fine particles in the part of the gas to be measured are mixed. The charged fine particles to which the ions are attached are configured to be returned to the vent tube, and the fine particle charging unit that forms a collecting electrode for collecting floating ions that are not attached to the fine particles among the ions, the first discharge electrode, and the The first conducting member that conducts to the fine particle charging unit, the first discharge electrode, and the second discharge electrode are electrically insulated and disposed in the fine particle charging unit to collect the floating ions by the collecting electrode. Supplement An auxiliary electrode conducting member, and an auxiliary electrode conducting member conducting to the auxiliary electrode. The first discharge electrode, the fine particle charging unit, and the first conducting member of the ion source have the first potential. The first potential member, the auxiliary electrode and the auxiliary electrode conducting member are the second potential members, and are auxiliary potential members that are the second potential and the auxiliary potential member, The insulating member is interposed between the fine particle charging unit and the auxiliary electrode conducting member, and the driving circuit is configured to pass the first discharge electrode of the ion source through the first conducting member when the detecting unit is driven. And the auxiliary first output terminal that is conducted to the fine particle charging unit and is set to the first potential, and when the detection unit is driven, the auxiliary electrode is energized through the auxiliary electrode conducting member, and this is set as the auxiliary electrode potential. Auxiliary second output And an auxiliary electrode drive circuit for driving the auxiliary electrode, wherein the drive availability determination means is between the first potential member and the auxiliary potential member inspected by the insulation inspection means. It is preferable to adopt a particulate detection system that determines whether or not the auxiliary electrode can be driven by the auxiliary electrode driving circuit according to the level of insulation.

  This system has the above-described ion source and fine particle charging unit. Therefore, the amount of fine particles can be detected based on the amount of electric charge attached to the charged fine particles returned to the vent pipe. That is, the magnitude of the signal current flowing between the first potential, which is the potential of the fine particle charging portion, and the potential of the vent pipe corresponds to the amount of charge discharged from the fine particle charging portion. Furthermore, this system has an auxiliary electrode. This auxiliary electrode is an electrode that assists in collecting floating ions by the collecting electrode of the charged particle part. Therefore, if the insulation between the charged particle part and the auxiliary electric potential member is lowered and the auxiliary electrode potential is lowered, the floating ions cannot be properly collected, and not only the charged fine particles but also the floating ions are charged with the fine particles. In some cases, the detection accuracy of the amount of the fine particles detected by being discharged from the portion to the vent pipe is lowered.

  In contrast, in this system, the first discharge electrode and the fine particle charging portion (first potential member) of the ion source, the auxiliary electrode and the auxiliary electrode conducting member (second potential member, auxiliary potential member) are insulative inspection means. Check the insulation between the two. The drive availability determination unit determines whether the auxiliary electrode can be driven by the auxiliary electrode drive circuit based on the level of insulation. Thereby, the amount of fine particles can be detected appropriately, and failure of the auxiliary electrode drive circuit can be prevented.

  Further, in the fine particle detection system described above, an auxiliary first switch that is interposed between the auxiliary first output end and the first conducting member to open and close the conduction between the two, and the auxiliary second output end And an auxiliary second switch that opens and closes the connection between the auxiliary electrode conducting member and a drive that closes the auxiliary first switch and the auxiliary second switch when the detection unit is driven. When the insulation between the first potential member and the auxiliary potential member is inspected by the auxiliary auxiliary switch closing instruction means and the insulation inspection means, the auxiliary first switch and the auxiliary second switch are respectively A fine particle detection system comprising an inspection auxiliary switch opening instruction means for opening the circuit is preferable.

  In this system, an auxiliary first switch is provided between the auxiliary first output end and the first conducting member, and an auxiliary second switch is provided between the auxiliary second output end and the auxiliary electrode conducting member. And when driving a detection part, since these are closed, an auxiliary electrode can be driven. On the other hand, when inspecting the insulation between the first potential member and the auxiliary potential member, each switch is opened. As a result, the auxiliary electrode drive circuit is disconnected, so that the auxiliary electrode drive circuit can be protected from the inspection voltage applied when the insulation is inspected, and the first potential member and the auxiliary electrode drive circuit are not affected by the auxiliary electrode drive circuit. The insulation between the auxiliary potential member can be appropriately inspected.

  The above-mentioned particulate detection system, further comprising: a heater that heats the insulating member; a heater energization circuit that energizes the heater; and a heater energization control unit that controls the heater energization circuit. When the insulation tested by the insulation test means is low, the unit instructs the heater energization circuit to energize the heater, heats the insulation member, and restores the insulation. A fine particle detection system having energization instruction means is preferable.

  In this system, when the insulation between the first potential member and the second potential member is low, the insulation is restored by energizing the heater to heat the insulation member. That is, by removing the foreign matter such as water droplets and soot adhering to the insulating member by heating, the insulating property is recovered. Thereby, in this system, it is possible to stably measure a gas to be measured including foreign matters such as water and soot.

  Further, in the fine particle detection system described above, the vent pipe may be an exhaust pipe of an internal combustion engine, and the gas to be measured may be a fine particle detection system that is an exhaust gas flowing through the exhaust pipe.

The exhaust gas (gas to be measured) flowing through the exhaust pipe of the internal combustion engine may contain a large amount of soot (fine particles) and water droplets (especially at startup). For this reason, in particular, soot accumulates on the insulating member that insulates between the first potential member and the second potential member, or water droplets adhere to the insulating member, and accordingly, the first potential member and the second potential. There is a possibility that the insulating property between the members is likely to deteriorate and the amount of the fine particles cannot be detected properly even if the detection unit is driven.
On the other hand, in this system, the insulation between the first potential member and the second potential member is inspected, and whether or not the detection unit can be driven is determined based on the level of insulation. Thereby, the amount of fine particles in the exhaust gas can be detected appropriately.

It is explanatory drawing explaining the state which applied the embodiment and applied the particulate detection system to the exhaust pipe of the engine mounted in the vehicle. It is explanatory drawing which shows schematic structure of the microparticle detection system concerning embodiment. FIG. 3 is a detailed explanatory diagram of a circuit unit in the schematic configuration illustrated in FIG. 2 according to the embodiment. It is a longitudinal section showing the structure of a detection part among particulate detection systems concerning an embodiment. It is a longitudinal cross-sectional view in the longitudinal cross section which shows the structure of the detection part among the microparticle detection systems concerning embodiment, and is orthogonal to the cross section of FIG. It is a disassembled perspective view which shows the structure of the detection part among the fine particle detection systems concerning embodiment. It is an expansion perspective view of an auxiliary electrode body and an auxiliary electrode insulating pipe with a heater according to the embodiment. It is explanatory drawing which illustrates typically the mode of taking in of a microparticle, charging, and discharge | emission within a microparticle charging part among the microparticle detection systems concerning embodiment. It is a flowchart which shows operation | movement of the microparticle detection system concerning embodiment. It is a flowchart which shows the content of the 1st insulation test subroutine. It is a flowchart which shows the content of the 2nd insulation test subroutine. It is a flowchart which shows the content of the detection part drive start subroutine. It is a flowchart which shows the content of the detection part drive stop subroutine.

A fine particle detection system 1 according to the present embodiment will be described with reference to the drawings. The particulate detection system 1 of the present embodiment is mounted on an exhaust pipe EP of an engine ENG (internal combustion engine) mounted on a vehicle AM, and determines the amount of particulate S (soot) in the exhaust gas EG flowing in the exhaust pipe EP. Detect (see FIG. 1). The system 1 mainly includes a detection unit 10, a circuit unit 201, and a pressure feed pump 300 that is a compressed air source that generates compressed air AK (see FIG. 2).
The detection unit 10 is attached to an attachment part EPT in which an attachment opening EPO is perforated in the exhaust pipe EP (venting pipe). A part thereof (in FIG. 2, the right side (front end side) of the attachment portion EPT) is disposed in the exhaust pipe EP through the attachment opening EPO, and is in contact with the exhaust gas EG (measured gas).
The circuit unit 201 is connected to the detection unit 10 via a cable 160 made of a plurality of wiring materials outside the exhaust pipe EP. The circuit unit 201 includes a circuit that drives the detection unit 10 and detects a signal current Is described later.

First, the configuration on the electric circuit of the circuit unit 201 in the system 1 will be described with reference to FIGS. 2 and 3. The circuit unit 201 includes a measurement control circuit 220 including a signal current detection circuit 230 and a heater energization circuit 226, an ion source power supply circuit 210 (ion source drive circuit), an auxiliary electrode power supply circuit 240 (auxiliary electrode drive circuit), and ground insulation. It has an inspection circuit 215, an auxiliary electrode insulation inspection circuit 245, a first relay RL1, and a second relay RL2.
Among these, the ion source power supply circuit 210 (ion source drive circuit) has a first output terminal 211 having a first discharge potential PV1 and a second output terminal 212 having a second discharge potential PV2. . Specifically, the second discharge potential PV2 is a positive high potential with respect to the first discharge potential PV1. More specifically, the second output terminal 212 outputs a positive pulse voltage of 1 to 2 kV0-p obtained by half-wave rectifying a sine wave of about 100 kHz with respect to the first discharge potential PV1. The ion source power supply circuit 210 constitutes a constant current power source that is feedback-controlled for its output current and autonomously maintains its effective value at a predetermined current value (for example, 5 μA).

  On the other hand, the auxiliary electrode power supply circuit 240 (auxiliary electrode driving circuit) has an auxiliary first output terminal 241 that is set to the first discharge potential PV1 and an auxiliary second output terminal 242 that is set to the auxiliary electrode potential PV3. . Specifically, the auxiliary electrode potential PV3 is a positive DC high potential with respect to the first discharge potential PV1, but is lower than the peak potential (1-2 kV) of the second discharge potential PV2, for example, DC100 It is set to a potential of ~ 200V.

  Further, the signal current detection circuit 230 forming a part of the measurement control circuit 220 includes a signal input terminal 231 connected to the first output terminal 211 of the ion source power supply circuit 210 and a ground input terminal 232 connected to the ground potential PVE. Have. The signal current detection circuit 230 is a circuit that detects a signal current Is described later.

The first relay RL1 has a two-pole switching contact that forms a first switch 213 and a second switch 214. The ground insulation test circuit 215 has a first test end 216 and a second test end 217.
When the coil (not shown) of the first relay RL1 is not energized, the first switch 213 conducts (closes) between the c and b terminals, and detects the first output terminal 211 of the ion source power supply circuit 210 and the signal current detection. The signal input terminal 231 of the circuit 230 is connected to the first potential wiring 165 of the cable 160 through the inner circuit case 250. On the other hand, the c−a terminals are not conductive, and the first inspection end 216 of the ground insulation inspection circuit 215 is disconnected from the inner circuit case 250 and the first potential wiring 165 of the cable 160. In the second switch 214, the c-b terminals are electrically connected (closed), and the second output terminal 212 of the ion source power supply circuit 210 is connected to the second potential wiring 161 of the cable 160.
On the other hand, when the coil of the first relay RL1 is energized, the first switch 213 becomes non-conductive (open circuit) between the c and b terminals, and the first output terminal 211 of the ion source power supply circuit 210 and the signal current detection. The signal input terminal 231 of the circuit 230 is disconnected from the inner circuit case 250 and the first potential wiring 165 of the cable 160. On the other hand, the c−a terminals are conducted, and the first inspection end 216 of the ground insulation inspection circuit 215 is connected to the first potential wiring 165 of the cable 160 through the inner circuit case 250. The second switch 214 is non-conductive (open) between the c-b terminals (conducted between the c-a terminals), and the second output terminal 212 of the ion source power supply circuit 210 is connected to the second potential wiring of the cable 160. It is separated from 161.
The second inspection terminal 217 of the ground insulation inspection circuit 215 is connected to the ground input terminal 232 of the signal current detection circuit 230 and is set to the ground potential PVE.

The second relay RL <b> 2 has a two-pole switching contact that forms an auxiliary first switch 243 and an auxiliary second switch 244. The auxiliary electrode insulation inspection circuit 245 has an auxiliary first inspection end 246 and an auxiliary second inspection end 247.
When the coil (not shown) of the second relay RL2 is not energized, the auxiliary first switch 243 is electrically connected (closed) between the c and b terminals, and the auxiliary first output terminal 241 of the auxiliary electrode power circuit 240 is It is connected to the first potential wiring 165 of the cable 160 through the inner circuit case 250. On the other hand, the c−a terminals are not conductive, and the auxiliary first inspection end 246 of the auxiliary electrode insulation inspection circuit 245 is disconnected from the inner circuit case 250 and the first potential wiring 165 of the cable 160. The auxiliary second switch 244 is electrically connected (closed) between the c and b terminals, and the auxiliary second output terminal 242 of the auxiliary electrode power circuit 240 is connected to the auxiliary potential wiring 162 of the cable 160. On the other hand, the c−a terminal is not conductive, and the auxiliary second inspection end 247 of the auxiliary electrode insulation inspection circuit 245 is disconnected from the auxiliary potential wiring 162 of the cable 160.
On the other hand, when the coil of the second relay RL2 is energized, the auxiliary first switch 243 becomes non-conductive (open circuit) between the c and b terminals, and the auxiliary first output terminal 241 of the auxiliary electrode power circuit 240 is inward. The circuit case 250 and the first potential wiring 165 of the cable 160 are disconnected. On the other hand, the c-a terminals are conducted, and the auxiliary first inspection end 246 of the auxiliary electrode insulation inspection circuit 245 is connected to the first potential wiring 165 of the cable 160 through the inner circuit case 250. The auxiliary second switch 244 is non-conductive (open) between the c and b terminals, and the auxiliary second output terminal 242 of the auxiliary electrode power circuit 240 is disconnected from the auxiliary potential wiring 162 of the cable 160. On the other hand, the c−a terminals are electrically connected, and the auxiliary second inspection end 247 of the auxiliary electrode insulation inspection circuit 245 is connected to the auxiliary potential wiring 162 of the cable 160.

  The heater energization circuit 226 is a circuit that energizes and heats a heater 78 (described later) by PWM control. The heater energization end 226a connected to the first heater connection wiring 169a of the cable 160; A second heater energization end 226b connected to the second heater connection wiring 169b of the cable 160 is provided.

In addition, in this circuit unit 201, the ion source power supply circuit 210, the auxiliary electrode power supply circuit 240, the ground insulation test circuit 215, the auxiliary electrode insulation test circuit 245, the first relay RL1, and the second relay RL2 It is surrounded by an inner circuit case 250 having a discharge potential PV1. The c terminal of the first switch 213 (first relay RL1) and the c terminal of the auxiliary first switch 243 (second relay RL2) are connected to the inner circuit case 250.
In this embodiment, the inner circuit case 250 includes the ion source power circuit 210, the auxiliary electrode power circuit 240, the ground insulation test circuit 215, the auxiliary electrode insulation test circuit 245, the first relay RL1, and the second relay RL2. In addition, the secondary side iron core 271B of the insulating transformer 270 is accommodated and surrounded, and is electrically connected to the first potential wiring 165 of the cable 160.

  On the other hand, the insulation transformer 270 has an iron core 271 wound around a primary iron core 271A wound around a primary coil 272 and a secondary iron core 271B wound around a power circuit coil 273 and an auxiliary electrode power supply coil 274. It is configured separately. Among these, the primary side iron core 271A is conducted to the ground potential PVE, and the secondary side iron core 271B is conducted to the first discharge potential PV1 (the first output terminal 211 of the ion source power supply circuit 210).

Further, a measurement control circuit 220 including a signal current detection circuit 230 and a heater energization circuit 226, an ion source power supply circuit 210, an auxiliary electrode power supply circuit 240, a ground insulation test circuit 215, an auxiliary electrode insulation test circuit 245, and a first relay. The RL1, the second relay RL2, and the inner circuit case 250 are surrounded by an outer circuit case 260 that conducts to the ground input terminal 232 of the signal current detection circuit 230 and is set to the ground potential PVE. Further, in addition to the ground input terminal 232 of the signal current detection circuit 230, the primary iron core 271 </ b> A of the isolation transformer 270 is connected to the outer circuit case 260.
In this embodiment, the outer circuit case 260 includes an ion source power supply circuit 210, an auxiliary electrode power supply circuit 240, a ground insulation test circuit 215, an auxiliary electrode insulation test circuit 245, a first relay RL1, and a second relay RL1. The relay RL2, the inner circuit case 250, the measurement control circuit 220, and the primary iron core 271A of the insulation transformer 270 are accommodated and surrounded, and are electrically connected to the ground potential wiring 167 of the cable 160.

The measurement control circuit 220 includes a regulator power source PS. The regulator power supply PS is driven by an external battery BT through the power supply wiring BC.
The measurement control circuit 220 includes a microprocessor 202 and can communicate with the control unit ECU that controls the internal combustion engine via the communication line CC. The measurement result (signal current Is) of the signal current detection circuit 230 described above. ), A value obtained by converting this into a fine particle amount, or a signal indicating whether or not the fine particle amount exceeds a predetermined amount can be transmitted to the control unit ECU. As a result, the control unit ECU can perform operations such as controlling the internal combustion engine and issuing a malfunction warning of a filter (not shown).

Part of the electric power input from the outside to the measurement control circuit 220 through the regulator power supply PS is distributed to the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 via the isolation transformer 270. The insulating transformer 270 forms a primary coil 272 that forms part of the measurement control circuit 220, a power circuit coil 273 that forms part of the ion source power circuit 210, and a part of the auxiliary electrode power circuit 240. The auxiliary electrode power supply side coil 274 and the iron core 271 (primary side iron core 271A, secondary side iron core 271B) are insulated from each other. For this reason, while electric power can be distributed from the measurement control circuit 220 to the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240, insulation between them can be maintained.
In the present embodiment, the insulating transformer 270 also serves as an auxiliary electrode insulating transformer that supplies power to the auxiliary electrode power supply circuit 240.
On the other hand, the ground insulation test circuit 215 and the auxiliary electrode insulation test circuit 245 are supplied with power from the regulator power supply PS through a power supply wiring (not shown) as in the measurement control circuit 220.

  The pressure feed pump 300 takes in the ambient air (air) around itself and is directed toward an ion gas injection source 11 described later through an air feed pipe 310 having tip portions inserted into the outer circuit case 260 and the inner circuit case 250. Then, clean compressed air AK is pumped.

  Next, the cable 160 will be described (see FIG. 2). At the center of the cable 160, a second potential wiring 161 made of copper wire, an auxiliary potential wiring 162, a first heater connection wiring 169a and a second heater connection wiring 169b, and a hollow air pipe 163 made of resin are arranged. Yes. These radial circumferences are surrounded by an inner insulator layer 164.

Further, the inner periphery of the inner insulator layer 164 is surrounded by a first potential wiring 165 made of a braided copper fine wire. In addition, an insulating insulator coating layer 166 made of resin is disposed around the first potential wiring 165 in the radial direction. Further, the circumference in the radial direction is covered with a ground potential wiring 167 made of a braided copper fine wire. An insulating outer insulating coating layer 168 made of resin is formed around the ground potential wiring 167 in the radial direction for protection.
In addition, the cable 160 can circulate gas in the longitudinal direction of the cable 160 through the gas flow passage 163H in the air pipe 163.

As described above, the circuit unit 201 is connected to the cable 160 (see FIG. 2). Specifically, the second output terminal 212 of the ion source power supply circuit 210 is connected to the second potential wiring 161 via the second switch 214 of the first relay RL1, and when the ion source power supply circuit 210 is driven. The second discharge potential PV2. The auxiliary second output terminal 242 of the auxiliary electrode power circuit 240 is connected to the auxiliary potential wiring 162 via the auxiliary second switch 244 of the second relay RL2. The electrode potential is PV3. Further, the first output terminal 211 of the ion source power circuit 210 and the signal input terminal 231 of the signal current detection circuit 230 are connected to the auxiliary first output terminal of the auxiliary electrode power circuit 240 via the first switch 213 of the first relay RL1. 241 is connected to the inner circuit case 250 and the first potential wiring 165 through the auxiliary first switch 243 of the second relay RL2, and is set to the first discharge potential PV1 when the ion source power supply circuit 210 is driven. . In addition, the ground input terminal 232 of the signal current detection circuit 230 is connected to and connected to the outer circuit case 260 and the ground potential wiring 167 to be the ground potential PVE.
The first heater energization end 226a of the heater energization circuit 226 is connected and conducted to the first heater connection wiring 169a, and the second heater energization end 226b of the heater energization circuit 226 is connected and conducted to the second heater connection wiring 169b. doing.
In addition, the air supply pipe 310 of the pressure pump 300 is communicated with the air pipe 163 of the cable 160 through the inside circuit case 250.

  Next, the mechanical configuration of the system 1 will be described with reference to FIGS. 4 and 5, the upper side in the figure is the front end side, and the lower side in the figure is the base end side. Note that the description of the mechanical configuration of the circuit unit 201 described above is omitted.

  First, the detection part 10 is demonstrated (refer FIGS. 4-7). As described above, the detection unit 10 is mounted on the mounting portion EPT having the mounting opening EPO in the exhaust pipe EP (venting pipe) of the engine ENG (internal combustion engine), and contacts the exhaust gas EG (measured gas). The detection unit 10 is roughly composed of an ion gas ejection source 11, a fine particle charging unit 12, a first conduction member 13, a needle electrode body 20, and an auxiliary electrode body 50 in terms of its electrical functions.

On the distal end side of the cable 160, the second potential wiring 161, the auxiliary potential wiring 162, the first heater connection wiring 169a, and the second heater connection wiring 169b are respectively inserted into an insulating separator 85, and together with the separator 85, a metal The inner cylinder 80 is held inside. The air pipe 163 has an open end 163S in the inner cylinder 80, and the central vent 85H of the separator 85 serves as a passage for the compressed air AK discharged from the air pipe 163.
The inner cylinder 80 is externally fitted to the distal end side of the cable 160 and is caulked and connected to the first potential wiring 165 covering the outer side of the inner insulating layer 164 of the cable 160 to cover the first potential. The wiring 165 is electrically connected.

  The distal end side of the second potential wiring 161 of the cable 160 is connected to the extending portion 21 of the needle electrode body 20 in the separator 85 inside the inner cylinder 80. This needle-shaped electrode body 20 is made of a tungsten wire, and has a substantially straight rod-shaped extension portion 21 and a second discharge electrode that is located at the tip portion (upper end portion in the figure) and has a needle-like shape. It comprises a needle-like tip portion 22 formed. Further, the extension portion 21 of the needle electrode body 20 is covered with a cylindrical needle electrode insulating pipe 75 made of an insulating ceramic such as alumina and perforated in a holding portion 61 of a metal pipe holder 60. It is inserted into the needle electrode insertion hole 61 </ b> H and held by the holding portion 61 together with the needle electrode insulating pipe 75.

  Further, the distal end side of the auxiliary potential wiring 162 of the cable 160 is connected to the extending portion 51 of the auxiliary electrode body 50 in the separator 85 inside the inner cylinder 80. The auxiliary electrode body 50 is made of a stainless steel wire, and includes an approximately straight rod-like extension portion 51, a bent-back portion 52 bent back in a U-shape on the tip end side, and an auxiliary electrode portion 53 forming an auxiliary electrode. Become. It should be noted that the tip portion of the auxiliary electrode portion 53 is also shaped like a needle, which is a needle-like tip portion 53S. Further, the extension portion 51 of the auxiliary electrode body 50 is covered with an auxiliary electrode insulating pipe 79 with a heater, and is inserted into the auxiliary electrode insertion hole 61I drilled in the holding portion 61 of the pipe holder 60 together with the pipe 79. And is held by the holding portion 61. The auxiliary electrode insulating pipe 79 with a heater includes a cylindrical auxiliary electrode insulating pipe 77 made of an insulating ceramic such as alumina, a heater 78 formed and integrated on the surface, and an insulating ceramic layer 76 covering them. (See FIG. 7). Further, the auxiliary electrode insulating pipe 79 with a heater has two heater terminals 78a and 78b of the heater 78 exposed on the base end side (lower side in FIG. 7). The heater 78 is made of tungsten, extends from the heater terminals 78a and 78b toward the distal end side (upward in FIG. 7), the heater lead portions 78r1 and 78r2, the first heater portion 78h1 positioned at the distal end portion, and the proximal end thereof. Two heating portions of the second heater portion 78h2 located on the side. The first heater part 78h1 and the second heater part 78h2 are connected in parallel. These are formed on the surface of the auxiliary electrode insulating pipe 77, and further, these surfaces are covered with an insulating ceramic layer 76 such as alumina to constitute an auxiliary electrode insulating pipe 79 with a heater.

  The first heater connection wiring 169a and the second heater connection wiring 169b of the cable 160 are connected to the heater connection terminals 170a and 170b in the separator 85 inside the inner cylinder 80, respectively. The heater connection terminals 170 a and 170 b extend to the front end side of the separator 85 in the inner cylinder 80 and are connected to the heater terminals 79 a and 79 b of the heater 78.

  The air pipe 163 of the cable 160 has an open end 163S in the inner cylinder 80 as described above. Further, a pipe holder 60 is fitted on the distal end side of the inner cylinder 80. For this reason, the compressed air AK released from the air pipe 163 passes through the ventilation hole 85H of the separator 85 and the ventilation through hole 61J drilled in the holding portion 61 of the pipe holder 60, and the discharge space DS ( (To be described later).

A pipe holder 60 shown in FIGS. 4 to 6 is made of stainless steel, and has a solid columnar holding portion 61, and a cylindrical tube wall portion 63 that extends from the periphery of the holding portion 61 to the tip side. Have Of these, the holding portion 61 has an annular holder flange portion 66 that bulges radially outward. In addition, the holding part 61 has a needle-like electrode insertion hole 61H, an auxiliary electrode insertion hole 61I, and a ventilation through-hole 61J extending in the vertical direction in the figure, and as described above, the needle-like electrode insertion hole The extension portion 21 of the needle electrode body 20 is inserted and held in 61H, and the extension portion 51 of the auxiliary electrode body 50 is inserted and held in the auxiliary electrode insertion hole 61I. On the other hand, the needle-like tip portion 22 of the needle-like electrode body 20 protrudes from the holding portion 61 toward the tip side on the radially inner side of the cylindrical wall portion 63.
The pipe holder 60 is fitted and fixed to the inner cylinder 80 and is electrically conductive. The pipe holder 60 and the inner cylinder 80 form the first conductive member 13 that surrounds the extending portion 21 of the needle electrode body 20 and the extending portion 51 of the auxiliary electrode body 50.

Further, a bottomed cylindrical nozzle member 30, specifically, a nozzle portion 31 that forms the bottom thereof is fitted into the distal end side (upper side in the drawing) of the cylindrical wall portion 63 of the pipe holder 60. The nozzle member 30 is also made of stainless steel, and includes a nozzle portion 31 located at the bottom, and a cylindrical tube wall portion 33 extending from the periphery of the nozzle portion 31 to the tip side. Among these, the nozzle portion 31 has a concave shape whose center is directed toward the distal end side, and a fine through hole is formed at the center to form the nozzle 31N. On the other hand, the cylindrical wall portion 33 is perforated with an intake port 33I (see FIG. 5) (opened toward the downstream side of the exhaust pipe EP). As will be described later, the intake port 33I is an opening for taking the exhaust gas EG into a mixed region MX (described later) formed by the nozzle member 30 and the mixed discharge member 40.
In addition, the nozzle member 30 is fitted and fixed to the pipe holder 60, and is electrically connected to the first discharge potential PV1.

In this way, the nozzle portion 31 of the nozzle member 30 is fitted into the distal end side (upper side in the drawing) of the cylindrical wall portion 63 of the pipe holder 60, whereby a discharge space DS is formed therebetween. In this discharge space DS, the needle-like tip portion 22 of the needle-like electrode body 20 protrudes from the holding portion 61 of the pipe holder 60, and this needle-like tip portion 22 is in contact with the opposing surface 31 T that forms the concave shape of the nozzle portion 31. Facing each other. Accordingly, when a high voltage is applied between the needle-shaped tip 22 and the nozzle portion 31 (opposing surface 31T), air discharge occurs, and N ² , O ^2, etc. in the atmosphere are ionized, and positive ions (for example, N ₃₊ , O _2+, hereinafter also referred to as ions CP). Further, the compressed air AK is also supplied to the discharge space DS through the ventilation through hole 61J of the holding portion 61 of the pipe holder 60. For this reason, the air AR originating from the compressed air AK is ejected from the nozzle 31N of the nozzle portion 31 toward the mixed region MX (described later) on the tip side at a high speed, and the compressed air AK (air AR) ), The ions CP are also injected into the mixing region MX.

Further, a mixing / discharging member 40 (see also FIG. 6) is fitted on the tip end side (upper side in the drawing) of the cylindrical wall portion 33 of the nozzle member 30. The mixing and discharging member 40 is also made of stainless steel, and has a base end portion 41 located on the base end side (downward in the figure) and a cylindrical tip end side cylindrical wall portion extending from the periphery of the base end portion 41 to the tip end side. 43. Further, the distal end side of the distal end side cylinder wall portion 43 is closed by being covered with a lid member 48. Further, a discharge port 43O (opening toward the downstream side of the exhaust pipe EP) is formed in the distal end side cylindrical wall portion 43 at one location.
Of the mixed discharge member 40, the base end portion 41 is configured such that the inner space is narrowed in a slit shape by the collecting electrode 42 bulging inward. On the other hand, a cylindrical space is formed in the distal end side cylindrical wall portion 43. The collecting electrode 42 is formed with a notch 42K in accordance with the position of the inlet 33I of the nozzle member 30.
In addition, the mixed discharge member 40 is fitted and fixed to the nozzle member 30 and is electrically connected to the first discharge potential PV1.

  Thus, in the nozzle member 30, the front end side surface 31 </ b> S facing upward in the drawing of the nozzle portion 31, the cylindrical wall portion 33, and the base end portion 41 (collecting electrode 42) of the mixed discharge member 40, a substantially cylindrical space Is formed. This space forms a cylindrical mixed region MX1 in the mixed region MX described later. On the other hand, the slit-shaped internal space formed by the collecting electrode 42 at the base end portion 41 of the mixed discharge member 40 forms a slit-shaped mixed region MX2. Further, the cylindrical space in the distal end side cylinder wall portion 43 forms a discharge path EX communicating with the discharge port 43O. In addition, a lead-in path HK communicating from the intake port 33I to the mixing region MX (columnar mixing region MX1) is formed by the cutout portion 42K of the collecting electrode 42.

  As will be described later, when the air AR containing the ions CP is ejected from the nozzle 31N at a high speed, the ejected air AR passes through the columnar mixing region MX1, the slit-shaped mixing region MX2, and the discharge path EX. And is discharged from the discharge port 43O. Furthermore, since the atmospheric pressure in the cylindrical mixing region MX1 decreases due to the flow of the air AR injected at a high speed, the exhaust gas EG outside the intake port 33I passes through the intake passage HK from the intake port 33I and passes through the mixing region MX (circle). The columnar mixed region MX1 and the slit-shaped mixed region MX2) are incorporated. The taken-in exhaust gas EGI is mixed with the air AR containing the ions CP in the mixing region MX, and is discharged from the discharge port 43O via the discharge path EX together with the air AR.

  Further, the extension part 51 of the auxiliary electrode body 50 and the auxiliary electrode insulating pipe 77 surrounding the extension part 51 described above extend to the tip side (upward in the drawing) from the pipe holder 60 and the nozzle member 30, and the extension part A bent-back portion 52 connected to 51 is located in the distal end side cylindrical wall portion 43 (discharge path EX) of the mixed discharge member 40. And the auxiliary electrode part 53 which faces the base end side (downward in the figure) is located in the slit-shaped mixed region MX2 formed by the base end part 41 of the mixed discharge member 40.

  As shown in FIG. 4, a substantially cylindrical first insulating spacer 121 made of an insulating ceramic such as alumina is disposed on the distal end side (upper side in the drawing) of the holder flange portion 66 of the pipe holder 60. A substantially cylindrical second insulating spacer 122 made of an insulating ceramic such as alumina is also arranged on the base end side (lower side in the figure) of the holder flange portion 66. Further, a metal shell 90 made of stainless steel is disposed around these radial directions (in the horizontal direction in the figure).

The metal shell 90 includes a cylindrical portion 91 and a flange portion 95. Among these, the substantially cylindrical tubular portion 91 holds a holding hole 91 </ b> H that holds the pipe holder 60, the first insulating spacer 121, and the second insulating spacer 122 therein. Further, the base end side of the cylindrical portion 91 is a female screw portion 92 having a female screw formed on the inner wall.
On the other hand, the flange portion 95 is a plate shape projecting radially outward from the distal end portion of the cylindrical portion 91 and has a substantially oval outer shape. Moreover, it has the bolt through-holes 95H and 95H penetrated in own thickness direction (2 places in this embodiment).

Further, the plug fitting 100 is screwed to the female threaded portion 92 of the cylindrical portion 91 of the metal shell 90 with a male threaded portion 102 having a male thread formed on the outer periphery thereof. The stopper metal 100 has a substantially cylindrical shape and surrounds the inner cylinder 80 in a non-contact manner. Further, the plug fitting 100 has a distal end pressing portion 101 having a flat distal end surface 101S formed on the distal end side (upward in the drawing) of the male screw portion 102 and having a smaller diameter than the male screw portion 102. Further, on the base end side (downward in the drawing) from the male screw portion 102, there is a hexagonal portion 103 that protrudes in a flange shape toward the outer side in the radial direction and has a hexagonal outer periphery.
When the male threaded portion 102 of the stopper fitting 100 is screwed into the female threaded portion 92 of the metallic shell 90, the stopper fitting 100 advances to the distal end side, and the distal end pressing portion 101 presses the second insulating spacer 122 toward the distal end side. Then, this 2nd insulation spacer 122 presses the holder flange part 66 of the pipe holder 60 toward the front end side. Further, the holder flange portion 66 presses the first insulating spacer 121 toward the distal end side. The first insulating spacer 121 is engaged with the holding hole 91 </ b> H of the cylindrical portion 91 of the metal shell 90 through the plate packing 124. Thereby, the pipe holder 60, the 1st insulating spacer 121, the 2nd insulating spacer 122, the plate packing 124, and the stopper metal fitting 100 are hold | maintained at the metal fitting 90, and are integrated.
In addition, a first insulating spacer 121 and a second insulating spacer 122 are interposed between the pipe holder 60 and the metal shell 90 so as to separate and insulate them from each other. Of the pipe holder 60, the holder flange portion 66 projecting outward in the radial direction and the metal shell 90 (cylindrical portion 91) are spaced apart from each other to maintain insulation therebetween. Yes. Further, the first insulating spacer 121 is interposed between the cylindrical wall portion 63 of the pipe holder 60 and the exhaust pipe EP in a state where the detection unit 10 is mounted on the exhaust pipe EP to separate and insulate the two. Yes.

As shown in FIG. 5, when the detection unit 10 is attached, the nozzle member 30, the mixed discharge member 40, and the like are inserted into the exhaust pipe EP from the attachment opening EPO of the attachment part EPT in the exhaust pipe EP. The stud bolts EPB and EPB provided adjacent to the mounting opening EPO are respectively inserted into the bolt through holes 95H of the flange portion 95 and fastened with nuts EPN. Thereby, the detection part 10 including the metal shell 90 is fixed to the attachment part EPT of the exhaust pipe EP.
An annular gasket holding groove 96 is formed around the holding hole 91H in the front end side surface 90S of the metal shell 90, and the mounting portion EPT of the exhaust pipe EP and the metal shell 90 are held by this gasket holding. They are hermetically coupled through a copper gasket 130 disposed in the groove 96.
Thereby, the gasket 130, the metal shell 90, and the stopper metal 100 are set to the same ground potential PVE as that of the exhaust pipe EP.

Furthermore, a cylindrical outer cylinder 110 made of stainless steel is connected to the base end portion 104 of the stopper fitting 100. The outer cylinder 110 surrounds the inner cylinder 80 and the distal end portion 160 </ b> S of the cable 160 from the outside in the radial direction, and the distal end portion 110 </ b> S is laser-welded to the base end portion 104 of the plug fitting 100 over the entire circumference.
In addition, the base end portion 110 </ b> K of the outer cylinder 110 is fixed to the cable 160 by caulking, with the outer shape being reduced in diameter from the distal end side. At the same time, the caulking portion 110KK of the base end portion 110K of the outer cylinder 110 passes through the outermost outer insulating coating layer 168 of the cable 160 and is electrically connected to the ground potential wiring 167 therein. Thus, both the outer cylinder 110 and the ground potential wiring 167 are set to the ground potential PVE, like the exhaust pipe EP, through the metal shell 90, the plug fitting 100, and the gasket 130 made of metal.
In the present embodiment, in order to prevent the front end portion 160S of the cable 160 from swinging in the outer cylinder 110, a cylindrical shape is formed between the front end portion 160S of the cable 160 and the outer cylinder 110 from insulating rubber. A grommet 125 is interposed.

Next, the electrical functions and operations of each part of the particulate detection system 1 of the present embodiment will be described with reference to FIG. 8 in addition to FIGS. FIG. 8 schematically shows the electrical function and operation of the detection unit 10 of the system 1 for easy understanding, and there are parts different from the forms described in other figures. Please note that.
The acicular electrode body 20 is connected to and electrically connected to the second output end 212 of the ion source power supply circuit 210 via the second potential wiring 161 of the cable 160. Accordingly, as described above, the needle-like electrode body 20 is set to the second discharge potential PV2, which is a positive half-wave rectified pulse voltage of 100 kHz and 1-2 kV0-p with respect to the first discharge potential PV1. .
Further, the auxiliary electrode body 50 is connected to and connected to the auxiliary second output terminal 242 of the auxiliary electrode power circuit 240 via the auxiliary potential wiring 162 of the cable 160. Therefore, as described above, the auxiliary electrode body 50 is set to the auxiliary electrode potential PV3 that is a positive DC potential of 100 to 200 V with respect to the first discharge potential PV1.
Further, the inner cylinder 80, the pipe holder 60, the nozzle member 30, and the mixing and discharging member 40 are connected to the first output terminal 211 of the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 via the first potential wiring 165 of the cable 160. The auxiliary first output terminal 241, the inner circuit case 250 surrounding these circuits, and the signal input terminal 231 of the signal current detection circuit 230 are connected and conductive. These are the first discharge potential PV1.
In addition, the outer cylinder 110, the plug fitting 100, the metal fitting 90, and the gasket 130 are connected to the outer circuit case 260 and the signal surrounding the measurement control circuit 220 including the signal current detection circuit 230 via the ground potential wiring 167 of the cable 160. The current detection circuit 230 is connected to and connected to the ground input terminal 232. These are set to the same ground potential PVE as the exhaust pipe EP.

Accordingly, as described above, between the nozzle portion 31 (opposing surface 31T) that is set to the first discharge potential PV1 and the needle-like tip portion 22 that is set to the second discharge potential PV2 having a positive potential higher than the first discharge potential PV1. Then, air discharge, specifically, corona discharge occurs. More specifically, a positive needle corona PC in which a corona is generated around the needle-like tip 22 serving as the positive electrode is generated. As a result, N ² , O ^2, etc. in the atmosphere (air) forming the atmosphere is ionized and positive ions CP are generated. Part of the generated ions CP is jetted toward the mixing region MX through the nozzle 31N together with the compressed air AK (air AR) supplied to the discharge space DS.
In the present embodiment, the needle-like tip portion 22 corresponds to the second discharge electrode, and the nozzle portion 31 of the nozzle member 30 corresponds to the first discharge electrode. Further, the pipe holder 60 (holding portion 61, cylindrical wall portion 63), the nozzle portion 31 (first discharge electrode), and the needle-like tip portion 22 (second discharge electrode) surrounding the discharge space DS are ionized. The source 11 and the ion gas injection source 11 are formed.

When the air AR is injected into the mixing region MX (cylindrical mixing region MX1), as described above, the atmospheric pressure of the cylindrical mixing region MX1 decreases, so that the exhaust gas EG passes through the intake passage HK through the intake passage HK. It is taken into the mixing area MX (cylindrical mixing area MX1, slit-shaped mixing area MX2). The intake exhaust gas EGI is mixed with the air AR, and is discharged from the discharge port 43O via the discharge path EX together with the air AR.
At this time, if the exhaust gas EG contains fine particles S such as soot, the fine particles S are also taken into the mixing region MX as shown in FIG. By the way, the injected air AR contains ions CP. For this reason, the fine particles S such as soot that are taken in are attached to the ions CP to become positively charged fine particles SC, and in this state, the air passes through the mixing region MX and the discharge path EX, and is discharged from the discharge port 43O. It is discharged together with AR.
On the other hand, among the ions CP ejected to the mixed region MX, the floating ions CPF that have not adhered to the fine particles S receive a repulsive force from the auxiliary electrode portion 53 of the auxiliary electrode body 50 and are collected at the first discharge potential PV1. The mixed discharge member 40 (base end portion 41, distal end side cylinder wall portion 43) forming the pole 42 adheres to each portion and is not discharged (captured).

As shown in FIG. 2, the discharge current Id is supplied from the second output end 212 of the ion source power supply circuit 210 to the needle-shaped tip 22 in accordance with the air discharge in the ion gas injection source 11. Most of the discharge current Id flows into the nozzle unit 31 as the power reception current Ij and flows to the first output terminal 211 of the ion source power supply circuit 210. On the other hand, the collection current Ih resulting from the charge of the floating ions CPF collected by the collection electrode 42 also flows to the first output terminal of the ion source power supply circuit 210. That is, a received collection current Ijh (= Ij + Ih) that is the sum of the received current Ij and the collected current Ih flows into the first output terminal 211 of the ion source power supply circuit 210.
However, the power collection current Ijh is smaller than the discharge current Id by a current corresponding to the charge of the discharged ions CPH attached and discharged to the charged fine particles SC. Therefore, the signal current Is corresponding to the difference between the discharge current Id and the received and collected current Ijh (discharge current Id−received and collected current Ijh) flows between the first discharge potential PV1 and the ground potential PVE and balances. .
Therefore, the signal current Is corresponding to the charge amount of the discharged ions CPH discharged by the charged fine particles SC is detected by the signal current detection circuit 230, whereby the amount of the fine particles S in the exhaust gas EG can be detected.
In the present embodiment, the nozzle member 30, the mixed discharge member 40, and the lid member 48 that form the mixing region MX and the collecting electrode 42 correspond to the fine particle charging unit 12.

In addition, the pipe holder 60 (holding portion 61, cylindrical wall portion 63) and the inner cylinder 80 are electrically connected to the fine particle charging portion 12 and the nozzle portion 31 of the nozzle member 30, while the extending portion 21 of the needle electrode body 20. And the circumference of the extending portion 51 of the auxiliary electrode body 50 is surrounded.
In the present embodiment, the pipe holder 60 (the holding portion 61 and the cylindrical wall portion 63) and the inner cylinder 80 correspond to the first conductive member 13. Among these, the pipe holder 60 is the first conduction member 13 and also a part of the ion gas ejection source 11 as described above.

Further, the metal shell 90, the plug metal fitting 100, and the outer cylinder 110 are electrically connected to the exhaust pipe EP and set to the ground potential PVE, while the fine particle charging unit 12 (the nozzle member 30 and the like) and the first conductive member 13 described above. It is electrically insulated from the inner cylinder 80 or the like. Of these, the cylindrical portion 91, the plug fitting 100, and the outer cylinder 110 of the metallic shell 90 are the outside of the exhaust pipe EP (of the particulate charging unit 12, the ion gas injection source 11, and the first conducting member 13). 4 and FIG. 5, the part located below the exhaust pipe EP is surrounded. Specifically, the proximal portion of the extended portion 21 of the needle electrode body 20 and the extended portion 51 of the auxiliary electrode body 50, the holding portion 61 of the pipe holder 60, and the circumference of the inner cylinder 80 are surrounded. It is out.
In the present embodiment, the metal shell 90, the plug metal fitting 100, and the outer cylinder 110 correspond to the outer surrounding portion 14.

As described above, the extension portion 51 of the auxiliary electrode body 50 is integrally formed by forming the periphery thereof on the auxiliary electrode insulating pipe 79 with a heater, specifically, the auxiliary electrode insulating pipe 77 and the surface thereof. It is surrounded by a heater 78 and an insulating ceramic layer 76 covering them.
Of the extended portion 51 of the auxiliary electrode body 50, the tip exposed surface 51c exposed from the auxiliary electrode insulating pipe 77 on the tip side and disposed in the fine particle charging portion 12 is in contact with the exhaust gas EG (measured gas). doing. Further, the inner side surface 12c of the fine particle charging unit 12 is also in contact with the exhaust gas EG.
Of the auxiliary electrode insulating pipe 77 of the heater-equipped auxiliary electrode insulating pipe 79 and the insulating ceramic layer 76 covering the auxiliary electrode insulating pipe 77, the tip-side surface 79 c is in contact with the exhaust gas EG and the inner side surface 12 c of the particulate charging unit 12. And the tip exposed surface 51c of the extended portion 51 of the auxiliary electrode body 50.

  Further, the auxiliary electrode insulating pipe 79 with a heater is inserted into the auxiliary electrode insertion hole 61I drilled in the holding portion 61 of the pipe holder 60, and the first insulation is provided on the radially outer side on the distal end side of the pipe holder 60. Spacers 121 are arranged. The first insulating spacer 121 is interposed between the pipe holder 60 and the metal shell 90 to electrically insulate them, and in the exhaust pipe EP, the cylindrical wall portion 63 of the pipe holder 60 and the exhaust pipe They are electrically insulated from each other by interposing between them.

  Here, the outer peripheral surface 63c of the cylindrical wall part 63 of the pipe holder 60 is in contact with the exhaust gas EG. Further, the front surface 121c of the first insulating spacer 121 is interposed between the outer peripheral surface 63c of the cylindrical wall 63 of the pipe holder 60 and the inner surface EPi of the exhaust pipe EP.

That is, the first insulating spacer 121 is interposed between the pipe holder 60 (first conductive member 13) having the first discharge potential PV1 and the exhaust pipe EP and the metal shell 90 (outer surrounding portion 14) having the ground potential PVE. The both are electrically insulated from each other.
Further, the first conduction member 13 including the pipe holder 60 is connected to the c terminal of the first switch 213 of the first relay RL1 through the first potential wiring 165 of the cable 160 and the inner circuit case 250. When the coil of the first relay RL1 is energized, the first switch 213 is electrically connected between the c-a terminals, and the first inspection end 216 of the ground insulation inspection circuit 215 is connected to the inner circuit case 250 and the cable. The first potential wiring 165 of 160 is connected. The outer surrounding portion 14 including the metal shell 90 is connected to the ground input terminal 232 of the signal current detection circuit 230 and the second inspection terminal 217 of the ground insulation test circuit 215 through the ground potential wiring 167 and the outer circuit case 260 of the cable 160. It is connected to the.
In the system 1 of this embodiment, the ground insulation test circuit 215 includes an insulation test unit that tests the insulation between the first conduction member 13 and the exhaust pipe EP and the outer surrounding portion 14. When the inspected insulation property is high, the ion source power source circuit 210 instructs to drive the ion gas ejection source 11 and the fine particle charging unit 12.

On the other hand, the auxiliary electrode insulating pipe 77 and the insulating ceramic layer 76 of the auxiliary electrode insulating pipe 79 with a heater are connected to the fine particle charging portion 12 having the first discharge potential PV1 and the auxiliary electrode body 50 (extending portion) having the auxiliary electrode potential PV3. 51 and the auxiliary electrode portion 53) are electrically insulated from each other.
Further, the fine particle charging unit 12 is connected to the c terminal of the auxiliary first switch 243 of the second relay RL2 through the first conductive member 13, the first potential wiring 165 of the cable 160, and the inner circuit case 250. The auxiliary electrode body 50 is connected to the c terminal of the auxiliary second switch 244 of the second relay RL2 through the auxiliary potential wiring 162 of the cable 160. When the coil of the second relay RL2 is energized, the auxiliary first switch 243 conducts between the c-a terminals, and the auxiliary first inspection end 246 of the auxiliary electrode insulation inspection circuit 245 is connected to the inner circuit case. It is connected to the first potential wiring 165 of the cable 160 through 250. Further, the auxiliary second switch 244 is electrically connected between the c−a terminals, and the auxiliary second inspection end 247 of the auxiliary electrode insulation inspection circuit 245 is connected to the auxiliary potential wiring 162 of the cable 160.
In the system 1 of the present embodiment, the auxiliary electrode insulation inspection circuit 245 causes the fine particle charging unit 12 and the first conductive member 13 and the auxiliary electrode body 50 (the extension unit 51 and the auxiliary electrode unit 53) to be electrically connected thereto. Insulation inspection means for inspecting the insulation between them is provided. When the inspected insulation is high, driving of the auxiliary electrode body 50 (auxiliary electrode portion 53) by the auxiliary electrode power circuit 240 is instructed.

  The heater 78 of the auxiliary electrode insulating pipe 79 with a heater is connected to the heater energization circuit 226. In the system 1 of the present embodiment, when the insulation tested by the above-described insulation testing means is low, the heater energization circuit 226 is instructed to energize the heater 78, and the first insulation spacer 121 (the tip side surface 121c). ) And an auxiliary electrode insulation pipe 79 with a heater (tip-side surface 79c). As a result, the insulating properties of the first insulating spacer 121 and the auxiliary electrode insulating pipe 77 and the insulating ceramic layer 76 of the auxiliary electrode insulating pipe 79 with heater are restored.

The operation of the microprocessor 202 that executes the particulate detection routine in the system 1 will be described with reference to the flowchart of FIG.
When a key switch (not shown) of the engine ENG is turned on, the particulate detection system 1 (the microprocessor 202 of the measurement control circuit 220) is activated, and necessary initial settings are made in step S1. Thereafter, in step S2, it is determined whether or not there is an instruction to start particle detection by the ECU.

  If there is no instruction to start particle detection (No), step S2 is repeated to wait for an instruction to start particle detection by the ECU. And when there exists an instruction | indication of particulate detection start (Yes), it progresses to step S3.

In step S3, a first insulation inspection subroutine (to be described later) for inspecting insulation between the first conducting member 13 (first potential member) and the exhaust pipe EP and the outer surrounding portion 14 (ground potential member) is executed. To do.
Next, in step S4, it is determined whether or not the insulation property tested in the first insulation test in step S3 is high based on whether or not the leakage current Im1 is smaller than the reference value Im1s. If the insulation is low (No), the process proceeds to step S14. If the insulation is high (Yes), the process proceeds to step S5.
In step S5, a second insulation inspection subroutine (described later) for inspecting the insulation between the fine particle charging unit 12 (first potential member) and the auxiliary electrode body 50 (auxiliary electrode unit 53 and extending portion 51). Run.
Next, in step S6, it is determined whether or not the insulation inspected by the second insulation inspection in step S5 is high based on whether or not the leakage current Im2 is smaller than the reference value Im2s. If the insulation is low (No), the process proceeds to step S14. If the insulation is high (Yes), the process proceeds to step S7.
That is, the process proceeds to step S7 only when both the insulation inspected in the first insulation inspection in step S3 and the insulation inspected in the second insulation inspection in step S5 are high, and otherwise, the process proceeds to step S14. .

In step S7, an energization count value described later is cleared. In subsequent step S8, a detection unit driving start subroutine (described later) is executed to drive the ion gas ejection source 11 and the fine particle charging unit 12 by the ion source power source circuit 210, and the auxiliary electrode by the auxiliary electrode power source circuit 240. The driving of the auxiliary electrode portion 53 of the body 50 is started.
Thereafter, in step S9, the signal current Is is detected by the signal current detection circuit 230 to detect the fine particles.

  When the particulate detection in step S9 is completed, it is determined in subsequent step S10 whether or not there is an instruction to terminate particulate detection by the ECU. If there is no instruction to end the detection of fine particles (No), the process proceeds to step S11, and it is further determined whether or not it is an insulating reinspection timing. If it is determined in step S11 that it is not the timing of the re-inspection for insulation (No), the process returns to step S9 to repeat particle detection.

  On the other hand, if there is an instruction to end the particulate detection in step S10 (Yes), the process proceeds to step S13, and a detection unit drive stop subroutine described below is executed to perform the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240. After stopping the driving, the processing of the present particle detection routine is terminated.

  Further, if it is determined in step S11 that it is the timing of the re-inspection for insulation (Yes), the process proceeds to step S12, and the same detection unit drive stop subroutine as in step S13 is executed, and the ion source power supply circuit 210 and After stopping the driving of the auxiliary electrode power supply circuit 240, the process returns to step S3 to restart the insulation test.

Here, the detection unit drive stop subroutine of steps S12 and S13 will be described with reference to the flowchart of FIG.
First, in step S121, the driving of the ion source power supply circuit 210 is stopped, and the driving of the ion gas ejection source 11 and the fine particle charging unit 12 is stopped. Next, in step S122, the driving of the auxiliary electrode power circuit 240 is stopped, the driving of the auxiliary electrode portion 53 of the auxiliary electrode body 50 is stopped, and then the subroutine is finished.

On the other hand, also when it progresses to step S14 from step S4 or step S6, the above-mentioned detection part drive stop subroutine (same as step S12 and step S13) is performed, and the ion gas injection source 11 and particulate charging by the ion source power supply circuit 210 are performed. The driving of the unit 12 and the driving of the auxiliary electrode unit 53 of the auxiliary electrode body 50 by the auxiliary electrode power circuit 240 are stopped. Usually, when step S14 is executed, the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 are not driven in step S8. However, by executing the detection unit drive stop subroutine in step S14, the ion source power supply circuit 210, the auxiliary electrode power supply circuit 240 itself, and the detection unit 10 break down when the inspected insulation properties including some abnormality are low. It is possible to reliably prevent problems such as
Next, energization of the heater 78 by the heater energization circuit 226 is started in step S15. Thereafter, in step S16, it is determined whether or not the energization of the heater 78 has passed the specified energization time. If the specified energization time has not elapsed (No), step S16 is repeated. When the specified energization time has elapsed (Yes), the process proceeds to step S17, and energization of the heater 78 by the heater energization circuit 226 is stopped.
As a result, the first insulating spacer 121 (tip-side surface 121c) and the auxiliary electrode insulating pipe 79 with heater (tip-side surface 79c) are heated to remove foreign matters such as water and soot, and the first insulating spacer 121 and the heater. The insulating properties of the auxiliary electrode insulating pipe 77 and the insulating ceramic layer 76 of the attached auxiliary electrode insulating pipe 79 are restored.

  In step S18, the energization count value for counting the number of times the heater 78 is energized by the heater energization circuit 226 is incremented by one. In the subsequent step S19, it is determined whether or not the third energization of the heater 78 by the heater energization circuit 226 has been completed based on the energization count value. When the energization of the heater 78 does not reach the third time (No), the process returns to step S3 again and is executed from the insulation test. On the other hand, when the heater 78 is energized for the third time (Yes), the process proceeds to step S20, where an abnormality is notified, and then the processing of the present particle detection routine is terminated. The reason why the insulating property is not recovered even after three times of heating is that it is considered that the state is abnormal.

Next, the first insulation inspection subroutine of step S3 will be described with reference to the flowchart of FIG.
In step S <b> 31, an instruction to open (switch) the first output terminal 211 of the ion source power supply circuit 210 and the first conduction member 13 by the first switch 213 is given. Along with this, the ground insulation test circuit 215 is connected to the first conduction member 13. Further, the opening of the second output end 212 of the ion source power supply circuit 210 and the needle-like electrode body 20 (extending portion 21) is instructed by the second switch 214.
Specifically, when the coil of the first relay RL1 is energized, the c-b terminals of the first switch 213 become non-conductive (open circuit) and the c-a terminals become conductive. As a result, the first output terminal 211 of the ion source power supply circuit 210 and the signal input terminal 231 of the signal current detection circuit 230 are disconnected from the first potential wiring 165 of the cable 160 and the first conductive member 13 electrically connected thereto. The first inspection end 216 of the ground insulation inspection circuit 215 is connected to these. Further, the c-b terminals of the second switch 214 become non-conductive (open circuit), and the second output end 212 of the ion source power supply circuit 210 is connected to the second potential wiring 161 of the cable 160 and the needle-like electrode body connected thereto. 20 and separated.

Next, in step S <b> 32, the inspection voltage Vm <b> 1 is applied between the first inspection end 216 of the ground insulation inspection circuit 215 that conducts to the first conduction member 13 and the second inspection end 217 that is set to the ground potential PVE.
Thereafter, in step S33, the exhaust pipe EP or the outer surrounding portion 14 between the first inspection end 216 and the second inspection end 217 of the ground insulation inspection circuit 215, that is, the first conducting member 13 and the ground potential PVE. Measure the leakage current Im1 flowing between and, and end the subroutine.

Next, the second insulation test subroutine of step S5 will be described with reference to the flowchart of FIG.
In step S <b> 51, an instruction to open (switch) the auxiliary first output terminal 241 of the auxiliary electrode power circuit 240 and the first conducting member 13 by the auxiliary first switch 243 is given. Further, the auxiliary second switch 244 instructs to open (switch) the auxiliary second output terminal 242 of the auxiliary electrode power circuit 240 and the auxiliary electrode body 50 (extending portion 51). Along with this, the auxiliary electrode insulation test circuit 245 is connected to the first conduction member 13 and the auxiliary electrode body 50.
Specifically, when the coil of the second relay RL2 is energized, the c-b terminals of the auxiliary first switch 243 become non-conductive (open circuit) and the c-a terminals become conductive. As a result, the auxiliary first output terminal 241 of the auxiliary electrode power circuit 240 is disconnected from the first potential wiring 165 of the cable 160 and the first conductive member 13 and the fine particle charging unit 12 which are electrically connected to the first potential wiring 165, while the auxiliary electrode insulation is provided. The auxiliary first inspection end 246 of the sex inspection circuit 245 is connected to these. Further, the c-b terminals of the auxiliary second switch 244 become non-conductive (open circuit), and the c-a terminals become conductive. As a result, the auxiliary second output terminal 242 of the auxiliary electrode power circuit 240 is disconnected from the auxiliary potential wiring 162 of the cable 160 and the auxiliary electrode body 50 conducted to the auxiliary potential wiring 162, while the auxiliary second inspection of the auxiliary electrode insulation inspection circuit 245 is performed. The end 247 is connected to these.

Next, in step S <b> 52, between the auxiliary first inspection end 246 of the auxiliary electrode insulation inspection circuit 245 that conducts to the first conduction member 13 and the fine particle charging unit 12 and the auxiliary second inspection end 247 that conducts to the auxiliary electrode body 50. The inspection voltage Vm2 is applied.
After that, in step S53, between the auxiliary first inspection end 246 and the auxiliary second inspection end 247 of the auxiliary electrode insulation inspection circuit 245, that is, the first conductive member 13, the fine particle charging unit 12, and the auxiliary electrode body 50 (extension). The leakage current Im2 flowing between the output part 51 and the auxiliary electrode part 53) is measured, and the subroutine is finished.

Next, the detection unit drive start subroutine in step S8 will be described with reference to the flowchart of FIG.
In step S <b> 81, the first switch 213 instructs to close (switch) the first output terminal 211 of the ion source power supply circuit 210 and the first conduction member 13. At the same time, the ground insulation test circuit 215 is disconnected from the first conductive member 13. Further, the second switch 214 instructs to close the second output end 212 of the ion source power supply circuit 210 and the needle-like electrode body 20 (extension portion 21).
Specifically, when the coil of the first relay RL1 is de-energized, the c-a terminals of the first switch 213 are non-conductive, and the c-b terminals are conductive (closed). As a result, the first inspection end 216 of the ground insulation inspection circuit 215 is disconnected from the first potential wiring 165 of the cable 160 and the first conduction member 13 conducted to the first potential wiring 165, while the first output end of the ion source power supply circuit 210. 211 and the signal input terminal 231 of the signal current detection circuit 230 are connected to these. Further, the c-b terminals of the second switch 214 are electrically connected (closed), and the second output terminal 212 of the ion source power supply circuit 210 is connected to the second potential wiring 161 of the cable 160 and the needle electrode body connected thereto. 20.

Next, in step S <b> 82, the auxiliary first switch 243 instructs to close (switch) the auxiliary first output terminal 241 of the auxiliary electrode power circuit 240 and the first conduction member 13. Further, the auxiliary second switch 244 instructs to close (switch) the auxiliary second output terminal 242 of the auxiliary electrode power supply circuit 240 and the auxiliary electrode body 50 (extending portion 51). At the same time, the auxiliary electrode insulation test circuit 245 is separated from the first conductive member 13 and the auxiliary electrode body 50.
Specifically, when the coil of the second relay RL2 is de-energized, the auxiliary first switch 243 becomes non-conductive between the c-a terminals and becomes conductive (closed) between the c-b terminals. As a result, the auxiliary first inspection end 246 of the auxiliary electrode insulation inspection circuit 245 is disconnected from the first potential wiring 165 of the cable 160, and the first conductive member 13 and the fine particle charging unit 12 that are electrically connected to the first potential wiring 165. The auxiliary first output terminal 241 of the electrode power supply circuit 240 is connected to these. Further, the c-a terminals of the auxiliary second switch 244 become non-conductive, and the c-b terminals become conductive (closed). As a result, the auxiliary second inspection end 247 of the auxiliary electrode insulation inspection circuit 245 is disconnected from the auxiliary potential wiring 162 of the cable 160 and the auxiliary electrode body 50 conducted therethrough, while the auxiliary second output of the auxiliary electrode power circuit 240 is provided. The end 242 is connected to these.

Next, in step S83, driving of the ion source power supply circuit 210 is started, the first discharge potential PV1 is applied to the ion gas ejection source 11 and the fine particle charging unit 12, and the first tip 22 of the needle electrode body 20 is subjected to the first discharge potential PV1. Two discharge potentials PV2 are applied. Subsequently, in step S84, driving of the auxiliary electrode power supply circuit 240 is started, and the auxiliary electrode potential PV3 is applied to the auxiliary electrode portion 53 of the auxiliary electrode body 50. Thus, after the driving of the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 is started, the subroutine is terminated, and the process proceeds to step S9 to perform particle detection.
In addition to the fine particle detection as described above, the first insulation test and the second insulation test are performed prior to the fine particle detection. If the insulation is low, the heater 78 is energized to provide insulation. Recover.

In the present embodiment, the microprocessor 202 of the measurement control circuit 220 corresponds to a drive control unit 225 that controls the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 and a heater energization control unit 227 that controls the heater energization circuit 226. Further, the microprocessor 202 executing the ground insulation test circuit 215 and step S3 (first insulation test) includes the first conduction member 13 (first potential member), the exhaust pipe EP, and the outer surrounding portion 14 (ground contact). This corresponds to an insulation inspection means for inspecting insulation between the potential member and the potential member. Further, the auxiliary electrode insulation test circuit 245 and the microprocessor 202 executing step S5 (second insulation test) include the fine particle charging unit 12 (first potential member) and the auxiliary electrode body 50 (auxiliary electrode unit 53 and This corresponds to an insulation inspection means for inspecting insulation with the extending portion 51).
In addition, the microprocessor 202 executing steps S4 and S6 corresponds to a drive availability determination unit. Further, the microprocessor 202 executing step S14 corresponds to drive stop means. Further, the microprocessor 202 executing steps S15 to S17 corresponds to the insulation recovery energization instruction unit.
Further, the microprocessor 202 executing step S81 corresponds to the driving switch closing instruction means. Further, the microprocessor 202 executing step S31 corresponds to the inspection switch opening instruction unit.
Further, the microprocessor 202 executing step S82 corresponds to the driving auxiliary switch closing instruction means. Further, the microprocessor 202 executing step S51 corresponds to the auxiliary switch opening instruction means at the time of inspection.

  As described above, in the system 1 of the present embodiment, the insulating test means is used between the first conduction member 13 (first potential member) and the vent pipe EP and the outer surrounding portion 14 (ground potential member). (1st insulation test). Then, the drive availability determination unit determines whether the ion source power supply circuit 210 can drive the ion gas ejection source 11 and the fine particle charging unit 12 based on the level of insulation between them. For this reason, the amount of fine particles S can be detected appropriately. Further, failure of the ion source power supply circuit 210 can be prevented.

  Furthermore, in the system 1 of the present embodiment, the first switch 213, the second output end 212, and the needle electrode body 20 are extended between the first output end 211 and the first conduction member 13 of the ion source power supply circuit 210. A second switch 214 is provided between each unit 21. Since these are closed when the detection unit 10 is driven, the detection unit 10 (the ion gas ejection source 11 and the fine particle charging unit 12) can be driven by the ion source power supply circuit 210. On the other hand, when inspecting the insulation between the first conduction member 13 (first potential member) and the vent pipe EP and the outer surrounding portion 14 (ground potential member), the first switch 213 and the second switch 214 are set. Open each one. Thereby, the ion source power supply circuit 210 is disconnected, so that the ion source power supply circuit 210 can be protected from the inspection voltage Vm1 applied when the insulation is inspected, and without being affected by the ion source power supply circuit 210, It is possible to appropriately inspect the insulation between the one conduction member 13 (first potential member) and the vent pipe EP and the outer surrounding portion 14 (ground potential member).

In the present embodiment, the relationship between the cylindrical wall portion 63 of the pipe holder 60, the exhaust pipe EP, and the first insulating spacer 121 in the exhaust pipe EP is determined by the potential of the first conduction member 13 including the pipe holder 60. A certain first discharge potential PV1 corresponds to the first potential in the present invention. The ground potential PVE that is the potential of the exhaust pipe EP and the outer surrounding portion 14 corresponds to the second potential in the present invention. The ion source power supply circuit 210 corresponds to the drive circuit and the ion source drive circuit in the present invention.
Further, the first discharge electrode 31, the fine particle charging unit 12, and the first conduction member 13 of the ion gas ejection source 11 correspond to a first potential member, and the outer surrounding portion 14 corresponds to a second potential member and a ground potential member. To do. Moreover, the extension part 21 of the acicular electrode body 20 corresponds to a second discharge electrode conducting member.
Further, the first insulating spacer 121 corresponds to an insulating member.

  Furthermore, in the system 1 of the present embodiment, the first discharge electrode 31 and the fine particle charging unit 12 (first potential member) of the ion source 11, the auxiliary electrode unit 53 of the auxiliary electrode body 50, and the extension are inspected by the insulating inspection unit. The insulation between the part 51 (auxiliary potential member) is inspected (second insulation inspection). The drive availability determination unit determines whether the auxiliary electrode unit 53 of the auxiliary electrode body 50 can be driven by the auxiliary electrode power circuit 240 based on the level of insulation. For this reason, the amount of fine particles S can be detected appropriately. In addition, failure of the auxiliary electrode power circuit 240 can be prevented.

  Further, in the system 1 of the present embodiment, the auxiliary first switch 243, the auxiliary second output terminal 242 and the auxiliary electrode body 50 are provided between the auxiliary first output terminal 241 and the first conduction member 13 of the auxiliary electrode power circuit 240. An auxiliary second switch 244 is provided between the extension portion 51 and the extension portion 51. Then, since these are closed when the detection unit 10 is driven, the auxiliary electrode unit 53 of the auxiliary electrode body 50 can be driven by the auxiliary electrode power circuit 240. On the other hand, the insulation between the first discharge electrode 31 and the fine particle charging portion 12 (first potential member) of the ion source 11 and the extension portion 51 and auxiliary electrode portion 53 (auxiliary potential member) of the auxiliary electrode body 50 is inspected. When doing so, the switches 243 and 244 are opened. Thereby, since the auxiliary electrode power circuit 240 is disconnected, the auxiliary electrode power circuit 240 can be protected from the inspection voltage Vm2 applied when inspecting the insulation, and the ion is not affected by the auxiliary electrode power circuit 240. The insulation between the first discharge electrode 31 and the fine particle charging portion 12 (first potential member) of the source 11 and the extension portion 51 and auxiliary electrode portion 53 (auxiliary potential member) of the auxiliary electrode body 50 can be appropriately inspected. .

In the present embodiment, in the relationship between the fine particle charging unit 12, the extension 51 of the auxiliary electrode body 50, and the auxiliary electrode insulating pipe 79 with a heater, the first discharge potential PV1 that is the potential of the fine particle charging unit 12 is This corresponds to the first potential in the present invention. Further, the auxiliary electrode potential PV3 that is the potential of the extended portion 51 and the auxiliary electrode portion 53 of the auxiliary electrode body 50 corresponds to the second potential in the present invention. The auxiliary electrode power supply driving circuit 240 corresponds to the driving circuit and the auxiliary electrode driving circuit in the present invention.
Furthermore, the first discharge electrode 31, the fine particle charging unit 12, and the first conduction member 13 of the ion gas ejection source 11 correspond to a first potential member, and the extension part 51 and the auxiliary electrode part 53 of the auxiliary electrode body 50 are It corresponds to a second potential member and an auxiliary potential member. Further, the extending portion 51 of the auxiliary electrode body 50 corresponds to an auxiliary electrode conducting member.
Furthermore, the auxiliary electrode insulating pipe 77 and the insulating ceramic layer 76 of the auxiliary electrode insulating pipe 79 with a heater correspond to an insulating member.

  Furthermore, in the system 1 of this embodiment, when the inspected insulation is low, the driving of the detection unit 10 by the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 is stopped. Thereby, when the insulation is low, particularly when the insulation is extremely low (short-circuit state), the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240 itself are driven by driving the ion source power supply circuit 210 and the auxiliary electrode power supply circuit 240. And malfunctions such as failure of the detection unit 10 can be reliably prevented.

Furthermore, in the system 1 of the present embodiment, the first potential member (the first conducting member 13 and the fine particle charging portion 12), the second potential member (the outer surrounding portion 14 (the ground potential member), and the extended portion of the auxiliary electrode body 50 are used. 51 (auxiliary electrode conducting member)), the first potential members 13 and 12 and the second potential member 14 are applied according to the magnitudes of leakage currents Im1 and Im2 flowing between them. Insulation with 51 is inspected.
In this method, it is only necessary to apply an inspection voltage between the first potential members 13 and 12 and the second potential members 14 and 51 to detect the flowing leakage currents Im1 and Im2, and easily inspect the insulation level. it can.

  Furthermore, in the system 1 of the present embodiment, the insulation between the first conduction member 13 (first potential member) and the outer surrounding member 14 (second potential member, ground potential member) or the fine particle charging unit 12 ( When the insulation between the first potential member) and the extending portion 51 (second potential member, auxiliary potential member) of the auxiliary electrode body 50 is low, the heater 78 is energized to insulate the insulating member (first insulating spacer 121). Then, the auxiliary electrode insulating pipe 77 and the insulating ceramic layer 76 of the auxiliary electrode insulating pipe 79 with a heater are heated to recover their insulating properties. That is, by heating, foreign matters such as water droplets and soot adhering to the insulating members 121, 77, and 76 are removed, and the insulating property is recovered. As a result, the system 1 can stably measure the exhaust gas EG (gas to be measured) containing foreign matters such as water and soot.

The exhaust gas EG flowing through the exhaust pipe EP of the internal combustion engine may contain a large amount of soot (fine particles S) and water droplets (especially at startup). For this reason, when the soot accumulates on the insulating members 121, 77, 76 that insulate the first potential members 13, 12 and the second potential members 14, 51 or water droplets adhere to the insulating members 121, 77 and 76, and therefore, the insulation between the first potential members 13 and 12 and the second potential members 14 and 51 is likely to deteriorate, and even when the detection unit 10 is driven, the amount of the fine particles S cannot be detected properly. There is a fear.
On the other hand, in the system 1 of the present embodiment, the insulation between the first potential members 13 and 12 and the second potential members 14 and 51 is inspected, and the detection unit 10 is driven when the insulation is high. The amount of the fine particles S in the exhaust gas EG can be detected appropriately.

In the above, the present invention has been described with reference to the system 1 of the embodiment. However, the present invention is not limited to the above embodiment, and it can be applied without departing from the gist of the present invention. Nor.
For example, in the embodiment, the first insulating spacer 121 (insulating member) is interposed between the first potential member 13 (the outer peripheral surface 63c of the cylindrical wall portion 63 of the pipe holder 60) and the inner side surface EPi of the exhaust pipe EP. The configuration was shown. However, depending on the shape of the exhaust pipe EP and the outer surrounding portion 14 (ground potential member (second potential member)), the outer surrounding portion 14 extends into the exhaust pipe EP, and the outer surrounding portion 14 becomes the exhaust gas EG (measured object). It is also possible to take a form in contact with (gas). In this case, the insulating member 121 may be interposed between the first potential member 13 and the ground potential member 14 (second potential member).

Moreover, in the said embodiment, test voltage Vm1, Vm2 is applied between the 1st electric potential members 13 and 12 and the 2nd electric potential members 14 and 51, and it isolates by the magnitude | size of the leakage current Im1 and Im2 which flow between both However, the insulation inspection method is not limited to this.
For example, the insulation resistance between the first potential members 13 and 12 and the second potential members 14 and 51 may be measured, or the first potential members 13 and 12 and the second potential members may be measured using a capacitance meter. The capacitance generated between the potential members 14 and 51 may be inspected.
Moreover, in the said embodiment, although both the 1st insulating spacer 121 (tip side surface 121c) and the auxiliary electrode insulation pipe 79 with heater (tip side surface 79c) were heated with the heater 78, either one of these was heated. It is good also as a structure which heats.
In the above embodiment, the example in which the detection unit 10 and the circuit unit 201 are connected via the cable 160 has been shown. However, the detection unit 10 and the circuit unit 201 are connected without using the cable 160. It is good also as a form.

EP exhaust pipe EPi (exhaust pipe) inner surface EPO mounting opening EG exhaust gas S particulate SC charged particulate CP ion CPF floating ion CPH exhaust ion Is signal current 1 particulate detection system 10 detector 11 ion gas injection source (ion source)
DS Discharge space 12 Particulate charging part (first potential member)
13 First conducting member (first potential member)
14 Outer enclosure (ground potential member)
20 Needle-like electrode body 21 (Extension part of needle-like electrode body) 22 Needle-like tip part (of needle-like electrode body) (second discharge electrode (ion source))
30 Nozzle member (ion source, particulate charging part)
31 Nozzle (first discharge electrode (ion source), fine particle charging unit, first potential member)
31N nozzle PV1 first discharge potential (first potential)
PV2 Second discharge potential PV3 Auxiliary electrode potential (second potential)
PVE ground potential (second potential)
40 Mixing and discharging member (particulate charging part)
MX mixing region 42 collecting electrode 48 lid member (particulate charging part)
50 Auxiliary electrode body 51 (Auxiliary electrode body) extending portion (auxiliary electrode conducting member, second potential member, auxiliary potential member)
53 Auxiliary electrode part (auxiliary electrode, second potential member, auxiliary potential member)
60 Pipe holder (first conducting member)
61 Holding part (first conductive member)
63 Cylindrical wall portion 76 (of pipe holder) Insulating ceramic layer (insulating member)
77 Auxiliary electrode insulation pipe (insulation member)
78 Heater 79 Auxiliary electrode insulation pipe 80 with heater Inner cylinder (first conductive member)
90 Metal shell (outer enclosure)
100 Plug fitting (outer enclosure)
110 Outer cylinder (outer enclosure)
121 First insulating spacer (insulating member)
160 Cable AK Compressed air (gas)
AR Air (gas)
S3 First insulation inspection (insulation inspection means)
S5 Second insulation test (insulation test means)
S4, S6 Drive availability determination means S14 Drive stop means S15 to S17 Insulation recovery energization instruction means S31 Inspection switch opening instruction means S51 Inspection auxiliary switch opening instruction means S81 Driving switch closing instruction means S82 Driving auxiliary switch closing instruction means Vm1 , Vm2 Inspection voltage Im1, Im2 Leakage current 201 Circuit unit 202 Microprocessor 210 Ion source power supply circuit (drive circuit, ion source drive circuit)
211 First output terminal 212 Second output terminal 215 Ground insulation test circuit (insulation test means)
220 Measurement control circuit 225 Drive control unit 226 Heater energization circuit 227 Heater energization control unit 230 Signal current detection circuit 240 Auxiliary electrode power supply circuit (drive circuit, auxiliary electrode drive circuit)
241 Auxiliary first output end 242 Auxiliary second output end 245 Auxiliary electrode insulation test circuit (insulation test means)

Claims (9)

A fine particle detection system for detecting the amount of fine particles in a gas to be measured flowing in a vent pipe,
A detection unit attached to the mounting opening of the vent pipe;
A drive circuit for driving the detection unit;
A drive control unit for controlling the drive circuit,
The detector is
A first potential member having a first potential in a state in which the detection unit is driven by the drive circuit;
A second potential member having a second potential different from the first potential in a state where the detection unit is driven by the drive circuit; and
An insulation member interposed between the first potential member and the second potential member to electrically insulate the two;
Insulation that inspects insulation between the first potential member and the second potential member to detect a decrease in insulation of the insulation member due to adhesion of foreign matter in the gas to be measured to the insulation member Inspection means,
The drive control unit
A fine particle detection system having a drive availability determination unit that determines whether the drive circuit can drive the detection unit based on the level of insulation tested by the insulation test unit. The particulate detection system according to claim 1,
The drive control unit
A particulate detection system comprising: a drive stopping unit that stops driving of the detection unit by the drive circuit when the insulation tested by the insulation testing unit is low. The fine particle detection system according to claim 1 or 2,
The insulation test means includes
A fine particle detection system, which is a first inspection unit that applies a test voltage between the first potential member and the second potential member to test a leakage current flowing between them or an insulation resistance between them. The fine particle detection system according to any one of claims 1 to 3,
The detector is
An ion source including a first discharge electrode and a second discharge electrode and generating ions by air discharge between them;
A portion of the gas to be measured that is electrically connected to the first discharge electrode of the ion source and circulates in the vent tube is mixed with the ions generated by the ion source, A fine particle charging unit configured to return the fine particles as charged fine particles to which the ions are attached to the vent pipe, and to collect a floating ion that does not adhere to the fine particles among the ions,
A first conducting member conducting to the first discharge electrode and the fine particle charging unit;
A second discharge electrode conducting member conducting to the second discharge electrode; and
A ground potential member that is the second potential member and is brought into contact with and conductive with the vent pipe to be the ground potential that is the second potential;
The first discharge electrode, the fine particle charging unit, and the first conduction member of the ion source are the first potential members that are set to the first potential,
The insulating member is interposed between the first potential member and the vent pipe or the ground potential member,
The drive circuit is
A first output terminal for energizing the first discharge electrode and the fine particle charging unit of the ion source through the first conduction member to drive the detection unit to the first potential; and
When the detection unit is driven, the second discharge electrode conducting member is energized to the second discharge electrode of the ion source, and this is used as a second discharge potential that generates a discharge between the second discharge electrode and the first discharge electrode. Including an output end,
An ion source driving circuit for driving the ion source and the fine particle charging unit;
The drive propriety judging means is
Driving the ion source and the fine particle charging unit by the ion source driving circuit due to the level of the insulation between the first potential member inspected by the insulation inspecting means and the ventilation pipe and the ground potential member. Particle detection system that determines whether or not it is possible. The fine particle detection system according to claim 4,
A first switch interposed between the first output end and the first conducting member to open and close the conduction between the two;
A second switch interposed between the second output end and the second discharge electrode conducting member to open and close the conduction between the two;
A driving switch closing instruction means for closing the first switch and the second switch when driving the detection unit;
When the insulation inspection means inspects the insulation between the first potential member and the vent pipe and the ground potential member, the first switch and the second switch are opened, respectively. And a particulate detection system. The fine particle detection system according to any one of claims 1 to 3,
The detector is
An ion source including a first discharge electrode and a second discharge electrode and generating ions by air discharge between them;
A portion of the gas to be measured that is electrically connected to the first discharge electrode of the ion source and circulates in the vent tube is mixed with the ions generated by the ion source, A fine particle charging unit configured to return to the vent pipe as charged fine particles in which the ions are attached to the fine particles, and which serves as a collecting electrode for collecting floating ions that are not attached to the fine particles among the ions.
A first conducting member conducting to the first discharge electrode and the fine particle charging unit;
An auxiliary electrode that is electrically insulated from the first discharge electrode and the second discharge electrode, and is disposed in the fine particle charging unit, and assists the collection of the floating ions by the collection electrode; and
An auxiliary electrode conducting member conducting to the auxiliary electrode,
The first discharge electrode, the fine particle charging unit, and the first conduction member of the ion source are the first potential members that are set to the first potential,
The auxiliary electrode and the auxiliary electrode conducting member are the second potential member, and are auxiliary potential members that are set to the auxiliary electrode potential that is the second potential,
The insulating member is interposed between the fine particle charging portion and the auxiliary electrode conducting member,
The drive circuit is
An auxiliary first output terminal that conducts to the first discharge electrode and the fine particle charging unit of the ion source through the first conduction member and is set to the first potential when the detection unit is driven;
An auxiliary second output terminal for energizing the auxiliary electrode through the auxiliary electrode conducting member during driving of the detection unit and setting the auxiliary electrode potential as the auxiliary electrode potential;
An auxiliary electrode driving circuit for driving the auxiliary electrode;
The drive propriety judging means is
A fine particle detection system for determining whether or not the auxiliary electrode can be driven by the auxiliary electrode driving circuit based on the level of the insulation between the first potential member and the auxiliary potential member inspected by the insulating inspection means. The fine particle detection system according to claim 6,
An auxiliary first switch that is interposed between the auxiliary first output end and the first conducting member to open and close the conduction between the two;
An auxiliary second switch interposed between the auxiliary second output end and the auxiliary electrode conducting member to open and close the conduction between the two;
A driving auxiliary switch closing instruction means for closing the auxiliary first switch and the auxiliary second switch, respectively, when the detection unit is driven;
Auxiliary switch opening instruction during inspection for opening the auxiliary first switch and the auxiliary second switch, respectively, when the insulation inspection means inspects the insulation between the first potential member and the auxiliary potential member. And a particulate detection system. The particulate detection system according to any one of claims 1 to 7,
A heater for heating the insulating member;
A heater energization circuit for energizing the heater;
A heater energization control unit for controlling the heater energization circuit,
The heater energization control unit
Insulation recovery energization instruction means for instructing the heater energization circuit to energize the heater and heating the insulating member to restore the insulation when the insulation inspected by the insulation inspection means is low. A particulate detection system having It is a particulate detection system according to any one of claims 1 to 8,
The vent pipe is an exhaust pipe of an internal combustion engine,
The particulate matter detection system, wherein the gas to be measured is an exhaust gas flowing through the exhaust pipe.

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