Microparticle detection system

Patent metadata

Field	Value
Publication number	US-9581069-B2
Application number	US-201314374247-A
Country	US
Kind code	B2
Filing date	Mar 8, 2013
Priority date	Mar 15, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A particulate detection system ( 1 ) for detecting the amount of particulates S in a gas under measurement EG includes a detection section ( 10 ), a drive circuit ( 210, 240 ), and a drive control section ( 225 ). The detection section includes a first potential member ( 31, 12, 13 ) maintained at a first potential PV 1 , a second potential member ( 14, 51, 53 ) maintained at a second potential PVE, PV 3 , and an insulating member ( 121, 77, 76 ) disposed between the first and second potential members. The system includes insulation test means ( 215 , S 3, 245 , S 5 ) for testing the degree of insulation between the first and second potential members. The drive control section includes drive permission/prohibition determination means S 4 , S 6 for determining, on the basis of the degree of insulation tested by the insulation test means, whether to permit the drive of the detection section by the drive circuit.

First claim

The invention claimed is:

1. A particulate detection system for detecting an amount of particulates in a gas under measurement flowing through a gas flow pipe, comprising:
a detection section which is mounted to a mounting opening of the gas flow pipe;
a drive circuit which drives the detection section; and
a drive control section which controls the drive circuit, wherein
the detection section includes
a first potential member which is maintained at a first potential when the detection section is driven by the drive circuit,
a second potential member which is maintained at a second potential different from the first potential when the detection section is driven by the drive circuit, and
an insulating member which is disposed between the first potential member and the second potential member so as to electrically insulate them from each other;
the system further comprises insulation test means for testing the degree of insulation between the first potential member and the second potential member; and
the drive control section includes drive permission/prohibition determination means for determining, on the basis of the degree of insulation tested by the insulation test means, whether to permit the drive of the detection section by the drive circuit.

2. A particulate detection system according to claim 1 , wherein the drive control section includes drive stoppage means for stopping the drive of the detection section by the drive circuit when the degree of insulation tested by the insulation test means is low.

3. A particulate detection system according to claim 1 , wherein the insulation test means is first test means for applying a test voltage between the first potential member and the second potential member and measuring a leak current flowing between the two members or an insulation resistance between the two members.

4. A particulate detection system according to claim 1 , wherein
the detection section includes
an ion source which has a first discharge electrode and a second discharge electrode and which produces ions by gaseous discharge between these electrodes,
a particulate electrifying section which electrically communicates with the first discharge electrode of the ion source and which is configured to mix a portion of the gas under measurement flowing through the gas flow pipe with the ions produced by the ion source and to return to the gas flow pipe electrified particulates which are particulates contained in the part of the gas under measurement and to which the ions adhere, the particulate electrifying section forming a capturing electrode which captures floating ions which are a portion of the ions and which did not adhere to the particulates,
a first communicating member which electrically communicates with the first discharge electrode and the particulate electrifying section,
a second discharge electrode communicating member which electrically communicates with the second discharge electrode, and
a ground potential member which is the second potential member and which is in contact with and electrically communicates with the gas flow pipe and is maintained at a ground potential which is the second potential;
the first discharge electrode of the ion source, the particulate electrifying section, and the first communicating member serve as the first potential member which is maintained at the first potential;
the insulating member intervenes between the first potential member and the gas flow pipe or the ground potential member; and
the drive circuit has a first output terminal for supplying electricity to the first discharge electrode of the ion source and the particulate electrifying section through the first communicating member when the detection section is driven, whereby the first discharge electrode and the particulate electrifying section are maintained at the first potential, and a second output terminal for supplying electricity to the second discharge electrode of the ion source through the second discharge electrode communicating member when the detection section is driven such that the second discharge electrode is maintained at a second discharge potential at which discharge occurs between the first discharge electrode and the second discharge electrode;
the drive circuit includes an ion source drive circuit which drives the ion source and the particulate electrifying section; and
the drive permission/prohibition determination means determines whether to permit the drive of the ion source and the particulate electrifying section by the ion source drive circuit, on the basis of the degree of insulation between the first potential member, and the gas flow pipe and the ground potential member tested by the insulation test means.

5. A particulate detection system according to claim 4 , further comprising:
a first switch which is disposed between the first output terminal and the first communicating member and which establishes and breaks electrical continuity between the first output terminal and the first communicating member;
a second switch which is disposed between the second output terminal and the second discharge electrode communicating member and which establishes and breaks electrical continuity between the second output terminal and the second discharge electrode communicating member;
drive-time switch closing instruction means for closing the first switch and the second switch when the detection section is driven; and
test-time switch opening instruction means for opening the first switch and the second switch when the degree of insulation between the first potential member, and the gas flow pipe and the ground potential member is tested by the insulation test means.

6. A particulate detection system according to claim 1 , wherein
the detection section includes
an ion source which has a first discharge electrode and a second discharge electrode and which produces ions by gaseous discharge between these electrodes,
a particulate electrifying section which electrically communicates with the first discharge electrode of the ion source and which is configured to mix a portion of the gas under measurement flowing through the gas flow pipe with the ions produced by the ion source and to return to the gas flow pipe electrified particulates which are particulates contained in the part of the gas under measurement and carrying the ions adhering to the particulates, the particulate electrifying section forming a capturing electrode which captures floating ions which are a portion of the ions and which did not adhere to the particulates,
a first communicating member which electrically communicates with the first discharge electrode and the particulate electrifying section,
an auxiliary electrode which is electrically insulated from the first discharge electrode and the second discharge electrode and which is disposed within the particulate electrifying section so as to assist the capturing of the floating ions by the capturing electrode, and
an auxiliary electrode communicating member which electrically communicates with the auxiliary electrode;
the first discharge electrode of the ion source, the particulate electrifying section, and the first communicating member serve as the first potential member which is maintained at the first potential;
the auxiliary electrode and the auxiliary electrode communicating member serve as an auxiliary potential member which is the second potential member and is maintained at an auxiliary electrode potential which is the second potential;
the insulating member is disposed between the particulate electrifying section and the auxiliary electrode communicating member;
the drive circuit has an auxiliary first output terminal which electrically communicates with the first discharge electrode of the ion sour

Assignees

• Ngk Spark Plug Co

Inventors

• Motomura Masayuki
• Sugiyama Takeshi
• Tashima Keisuke
• Matsuoka Toshiya
• Yokoi Hitoshi

Classifications

• F01N2560/05

  the means being a particulate sensor · CPC title

• G01N2015/0046

  in gas, e.g. smoke · CPC title

• G01N27/68

  using electric discharge to ionise a gas · CPC title

• G01N15/0656

  using electric, e.g. electrostatic methods or magnetic methods (by investigating individual particles G01N15/1031, G01N15/12) · CPC title

• G01M15/102

  by monitoring exhaust gases · CPC title