Microparticle sensor

Patent metadata

Field	Value
Publication number	US-9476807-B2
Application number	US-201314372521-A
Country	US
Kind code	B2
Filing date	Feb 13, 2013
Priority date	Feb 21, 2012
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

A particulate sensor including a sensor unit ( 300 ) having an ion generation section ( 611, 361, 322 ); an electric charge section ( 612 ) for electrically charging at least portion of particulates S using ions PI; a capture section ( 616, 617, 316, 326, 362 ) for trapping at least portion of the ions PI not used for electrically charging the particulates S; and a sensor ground section ( 340, 310 v, 330 v 3 ) connected to the capture section and having a first floating potential corresponding to the amount of the ions PI trapped by the capture section. The sensor unit can detect the amount of the particulates S in the gas on the basis of the electric potential of the sensor ground section. The sensor ground section is covered with insulating ceramic at that outer portion of the sensor unit which comes into contact with the gas.

First claim

The invention claimed is:

1. A particulate sensor attached to a pipe having electrical conductivity, and adapted to detect the amount of particulates in gas flowing through the pipe, comprising a sensor unit, wherein
the sensor unit comprises
an ion generation section for generating ions,
an electric charge section for electrically charging at least portion of the particulates in the gas which contains the particulates, by use of the ions,
a capture section for trapping at least portion of the ions not used for electrically charging the particulates, and
a sensor ground section connected to the capture section and having a first floating potential corresponding to the amount of the ions trapped by the capture section;

the sensor unit can detect the amount of the particulates in the gas on the basis of electric potential of the sensor ground section; and
the sensor ground section is covered with insulating ceramic at an outer portion of the sensor unit which comes into contact with the gas,
wherein
the ion generation section comprises a first electrode having a second floating potential different from the first floating potential, and a second electrode connected to the sensor ground section and having the first floating potential;
the ion generation section generates the ions by producing discharge between the first electrode and the second electrode;
the sensor unit further comprises a discharge potential portion connected to the first electrode and having the second floating potential; and
the sensor ground section surrounds the first electrode and the discharge potential portion.

2. The particulate sensor according to claim 1 , comprising
a structure formed of insulating ceramic and having the ion generation section, the electric charge section, the capture section, the sensor ground section, and the discharge potential portion, wherein
the discharge potential portion is covered with the insulating ceramic used to form the structure; and
the electric charge section is provided by the insulating ceramic used to form the structure.

3. The particulate sensor according to claim 2 , wherein the sensor unit further comprises a heater for heating the first and second electrodes and the capture section to a temperature capable of burning the particulates at the first and second electrodes and the capture section.

4. The particulate sensor according to claim 2 , wherein the sensor unit further comprises a heater for heating the electric charge section to a temperature capable of burning the particulates at the electric charge section.

5. The particulate sensor according to claim 3 , further comprising a protector surrounding the outer portion of the structure which comes into contact with the gas, and allowing the gas which contains the particulates to pass therethrough.

6. The particulate sensor according to claim 4 , further comprising a protector surrounding that outer portion of the structure which comes into contact with the gas, and allowing the gas which contains the particulates to pass therethrough.

Assignees

• Ngk Spark Plug Co

Inventors

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

Classifications

• G01N2291/02408

  Solids in gases, e.g. particle suspensions · CPC title

• F01N2560/05

  the means being a particulate sensor · CPC title

• G01M15/102

  by monitoring exhaust gases · CPC title

• G01N1/2252 Primary

  in a vehicle exhaust · CPC title

• F01N2560/02

  the means being an exhaust gas sensor · CPC title