Ngk Spark Plug Company, Limited

Toshiya Matsuoka

Takeshi Sugiyama

Masayuki Motomura

Keisuke Tashima

Hitoshi Yokoi

Norimasa Osawa

Satoshi Teramoto

Shigeki Mori

Takeshi Kawai

Tessho Yamada

Yuji Oi

Yuji Kimoto

Hirokazu Murase

Hisaharu Nishio

Kunihiko Yonezu

Tomohiro Tajima

A particulate sensor can reduce the amount of floating ions discharged from the interior of a gas introduction pipe to the outside through a gas discharge opening, without providing an auxiliary electrode member which applies to the floating ions a repulsive force toward the gas introduction pipe to thereby assist the collection of the floating ions by the gas introduction pipe. The particulate sensor has an collection member which is connected to a gas introduction pipe to thereby be maintained at a collection potential and is disposed in the interior of the gas introduction pipe to be located between a forward end of the discharge electrode member and a gas discharge opening such that the forward end of the discharge electrode member cannot be visually recognized from the outside of the gas introduction pipe through the gas discharge opening.

Particulate sensor

A particulate amount determination section of a particulate measurement system corrects a measurement signal or the amount of particulates determined from the measurement signal based on one or a plurality of three operating condition parameters selected from speed of the vehicle, rotational speed of the internal combustion engine and torque of the internal combustion engine.

Particulate measurement system

A particulate sensor includes: an inner metallic member which is maintained at a first potential and which has a gas introduction pipe into which a target gas is introduced; a tubular outer metallic member which surrounds the radially outer circumference of the inner metallic member and which is attached to a gas flow pipe to thereby be maintained at a ground potential; and an insulating spacer which is interposed between the inner metallic member and the outer metallic member so as to electrically insulate them from each other and which has a tubular gas contact portion which is exposed to the interior of the gas flow pipe and comes into contact with the gas under measurement. The insulating spacer has a heater for heating the gas contact portion. The heater includes a heat generation resistor embedded in the insulating spacer.

A particulate measurement system includes an ion generation section for generating ions by means of corona discharge; an electrification chamber for electrifying particulates contained in a gas under measurement; a measurement signal generation circuit for generating a measurement signal which correlates with the amount of the particulates; and a particulate amount determination section for determining the amount of the particulates. The particulate measurement system further includes a particle diameter estimation section for estimating the particle diameter of the particulates contained in the gas under measurement. The particulate amount determination section performs correction by multiplying the measurement signal or the amount of the particulates determined from the measurement signal by a coefficient relating to the ratio between the estimated particle diameter and a reference particle diameter.

A particle detection system includes a sensor main body having an electrification section for electrifying particles contained in a gas under measurement so as to produce electrified particles, and detects the particles contained in the gas under measurement by using the electrified particles. The sensor main body has a heater portion which generates heat upon energization so as to heat at least a portion of the electrification section. The particle detection system detects a burnable period (for example, fuel cut period) during which the gas under measurement contains oxygen for burning particles adhering to the electrification section, and energizes the heater portion during the burnable period so as to heat at least a portion of the electrification section to a temperature at which the adhering particles burn.

Particle detection system

A particulate sensor () includes an ion source () and a reference potential member (). The particulate sensor () detects particulates S contained in a gas under measurement EG by means of ions CP. The ion source () includes a ceramic structure () having a ceramic laminate () and a discharge electrode member (). The discharge electrode member () has an inter-layer portion (A,) embedded between the layers of the ceramic laminate () and an exposed portion (B) extending from the inter-layer portion (A,) to a position outside the ceramic laminate (). The discharge electrode member () generates the gaseous discharge between the reference potential member () and the exposed portion (B) including one or more needle-shaped distal end portions () upon application of a constant DC discharge potential PV

A particulate sensor () which detects particulates S contained in a gas under measurement (EG) flowing within a gas flow pipe (EP) has a space forming portion () and an ion source (). The space forming portion () projects into the gas flow pipe EP and forms an internal space MX. The space forming portion () has an introduction port (I) and a discharge port (O) for discharging from the internal space MX the gas EGI introduced through the introduction port (I). The source () produces ions CP by gaseous discharge. The space forming portion () is configured such that the introduced gas EGI is discharged from the internal space MX through the discharge port (O), the gas under measurement EG is introduced into the internal space MX through the introduction port (I), and the introduced gas EGI is mixed with the ions CP produced by the ion source ().

A particulate detection system () for detecting the amount of particulates S in a gas under measurement EG includes a detection section (), a drive circuit (), and a drive control section (). The detection section includes a first potential member () maintained at a first potential PV, a second potential member () maintained at a second potential PVE, PV, and an insulating member () disposed between the first and second potential members. The system includes insulation test means (, S, S) for testing the degree of insulation between the first and second potential members. The drive control section includes drive permission/prohibition determination means S, Sfor 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.

Microparticle detection system

A particulate sensor including a sensor unit () having an ion generation section (); an electric charge section () for electrically charging at least portion of particulates S using ions PI; a capture section () for trapping at least portion of the ions PI not used for electrically charging the particulates S; and a sensor ground section () 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.

Microparticle sensor

A particulate detection system () includes detection section (), compressed air source () which includes compressor () for producing compressed air AK, compressor drive circuit () and control means (). The detection section includes a gas jetting source (). A drive condition for jetting air AR from jetting hole (N) at a first flow rate Qis defined as a first drive condition JK, and a drive condition for jetting the air AR at a second flow rate Qsmaller than the first flow rate Qis defined as a second drive condition JK. The control means includes first instruction means Sfor driving the compressor under the first drive condition JKwhen the quantity of the particulates S is detected, and second instruction means Sfor driving the compressor under the second drive condition JKwhen the quantity of the particulates S is not detected.

A thin plate member which has a groove portion recessed toward the inside in a radial direction with a gap interposed between the thin plate member and the outer surface of a site on the front end side of a main body section. At least one end of the thin plate member is joined to the outer surface of the main body section and is provided radially outside the site on the front end side of the main body section. A seal member is disposed in the groove portion and has elasticity due to resin. Since the gap functions as a heat-insulating layer and is interposed between the seal member and the main body section, heat conduction from the main body section, that is, heat conduction through a first pathway is reduced, and thus deterioration of the seal member due to heat is suppressed.

Gas sensor

There is provided a fine particle detection system with a fine particle sensor, a cable and a sensor drive control device. The fine particle sensor has an ion source unit with first and second electrodes, a particle charging unit and inner and outer sensor casings. The cable has a power supply wiring line connected to the second electrode, an inner shield line electrically continuous with the inner sensor casing and an outer shield line electrically continuous with the outer sensor casing. The sensor drive control device has an ion-source power supply circuit, a signal current detection circuit, an inner circuit casing electrically continuous with a first output terminal of the ion-source power supply circuit and surrounding the ion-source power supply circuit and an outer circuit casing connected to the ground potential and shielding the ion-source power supply circuit, the signal current detection circuit and the inner circuit casing.

Fine particle detection system

There is provided a fine particle sensor for detecting fine particles in exhaust gas, including an ion generating unit for generating ions by corona discharge, a charging unit for charging the fine particles by some of the generated ions, an ion trapping unit for trapping a remainder of the generated ions and a casing for accommodating therein the charging unit and the ion trapping unit in a given arrangement direction. The casing has a gas inlet hole and a gas outlet hole formed in a circumferential wall thereof so that the exhaust gas flows in the charging unit through the gas inlet hole and flows out of the ion trapping unit through the gas outlet hole. The gas inlet hole and the gas outlet hole are arranged in such a manner as to at least partially overlap each other when viewed in the given arrangement direction.

Fine particle sensor and mounting structure therefor

It is an object of the invention to provide a gas detecting device capable of relieving the influence of an environment such as a temperature, a humidity or a wind velocity to detect a change in a concentration of a specific gas and an autoventilation system for a vehicle using the gas detecting device. More specifically, a gas detecting device () using a gas sensor element () changing a sensor resistance Rs depending on a concentration of a gas such as NOx and an autoventilation system () for a vehicle according to the invention A/D convert the output of a sensor resistance value converting circuit () to acquire a sensor output value S(n), calculates a base value B(n) based on B(n)=B(n&#x2212;1)+k{S(n)&#x2212;B(n&#x2212;1)}, and furthermore, calculates a difference value of D(n)=S(n)&#x2212;B(n). When the concentration of the gas is increased so that the difference value becomes greater than a predetermined concentration threshold, a high concentration signal is generated to close a flap () and a base value B(n) is calculated by using a coefficient kwhich is smaller than kbased on B(n)=B(n&#x2212;1)+k{S(n)&#x2212;B(n&#x2212;1)}.

Gas detector and automobile ventilation system

A gas detection apparatus incorporating a gas sensor element and a vehicle automatic ventilation system including the apparatus in which a sensor output value S(n) is obtained, and a base value B(n) is calculated by use of Expression (1): B(n)=B(n&#x2212;1)+k1[S(n)&#x2212;B(n&#x2212;1)]&#x2212;k2[S(n)&#x2212;S(n&#x2212;5)] in the case where S(n)&#x2267;B(n&#x2212;1), or by use of Expression (3): B(n)=S(n) in the case where S(n)&#x3c;B(n&#x2212;1), followed by calculation of a difference value D(n); i.e., S(n)&#x2212;B(n). When the difference value exceeds a predetermined high connection threshold, a high-concentration signal is generated to close a flap. After that, the base value B(n) is calculated by use of Expression (4): B(n)=B(n&#x2212;1)+k3[S(n)&#x2212;B(n&#x2212;1)]&#x2212;k4[S(n)&#x2212;S(n&#x2212;5)]. When the difference value becomes smaller than a predetermined low-concentration threshold, a low-concentration signal is generated to open the flap.

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Kaizu, Japan

Toshiya Matsuoka