Nippondenso Co., Ltd.

Nippon Soken, Inc.

Toyota Jidosha Kabushiki Kaisha

Morihiro Atsumi

Shunzo Yamaguchi

Hitoshi Yoshida

Takeshi Fukazawa

Kinya Atsumi

Novuei Ito

Kenji Yagi

Naotaka Nakamura

Ichirou Yoshida

Nobuei Ito

Manabu Yamada

Ichiro Yoshida

Naohito Mizuno

Naochika Nunogaki

Kiyoaki Tanaka

Tomio Kumoi

Kinya Atumi

A spark plug containing a resistor which is a sintered body made from a mixture comprising coarse glass particles and fine glass particles, coarse ceramic particles and fine ceramic particles, and carbon black in special proportions is improved in noise signal suppression effect.

Spark plug having a built-in resistor for suppressing noise signals

A spark plug having an improved radio noise suppression effect and durability of the resistor. The resistor of the spark plug is made of a sintered material comprising by weight, 0.9-3.0% of one of TiN, TiC, WC, TiB.sub.2, ZrC, HfC, SiC, TaC, MoSi.sub.2 and mixtures thereof, 9-40% of fine glass powder having a larger grain size than that of said conductive material, not more than 20% of magnetic substance, and 60-90% of coarse glass powder having a larger grain size than that of the fine glass powder. The composition is free of elemental carbon.

Spark plug

A distributor for an internal combustion engine, wherein a plurality of fixed electrodes which are respectively connected to a plurality of sparking plugs of an internal combustion engines, a rotating electrode rotatable in synchronism with a crank shaft of the internal combustion engine thereby forming sequentially a narrow gap with each of the fixed electrodes, and at least either the fixed electrodes or the rotatable electrode are made of such a ceramic that has the function of a varistor. Thereby the distributor is capable of suppressing noise current caused by spark discharge which is made between the rotating electrode and each of the fixed electrodes.

Ignition distributor for internal combustion engines

A ceramic heater has a heater element made of a mixture including MoSi.sub.2 and Si.sub.3 N.sub.4 powder as a main ingredient and silica (SiO.sub.2) powder as an additive, a heater support member made of an electrically insulating ceramic sintered body for supporting the heater element and an electric current supply means for supplying an electric current to the heater element. The composition of the mixture for the heater element is defined so as to satisfy the following formula: 0.035.ltoreq.B/A&lt;0.35 where A is the amount of Si.sub.3 N.sub.4 expressed by mol percent of the total amount of the main ingredient of MoSi.sub.2 and Si.sub.3 N.sub.4 and B is the amount of SiO.sub.2 expressed by mol percent of the total amount of the main ingredient of MoSi.sub.2 and Si.sub.3 N.sub.4.

Ceramic heater

An ignition distributor for use in internal combustion engines has a noise preventive function capable of suppressing the generation of radiowave noises due to the spark discharge produced between a rotary electrode and stationary electrodes disposed on the side of the rotational circumference thereof opposing thereto. The ignition distributor has stationary electrodes and a rotary electrode, in which each of the plurality of stationary electrodes or rotary electrode has a main body made of a sintering product composed of powdery zinc oxide and powdery ferrite and a surface layer mainly composed of ferrite integrally formed to the surface portion of the main body.

A sintered ceramic electric heater suitably applicable to a glow plug of a diesel engine has a heater element formed of an electrically conductive sintered ceramic integrally sintered with a support member made of an electrically insulating sintered ceramic material. The heater element is formed as a sintered body of a mixture of MoSi.sub.2 powder having an average diameter not greater than 2 .mu.m and 35 to 75 mol % of Si.sub.3 N.sub.4 powder. The average particle diameter of the Si.sub.3 N.sub.4 powder is at least twice as large as that of the MoSi.sub.2 powder so that electrically interconnecting MoSi.sub.2 particles surround scattered Si.sub.3 N.sub.4 particles whereby the resistance of the heater element becomes equal to that of MoSi.sub.2 and the temperature coefficient of the heater element is increased.

Sintered ceramic heater element

A sintered ceramic heater, particularly a heater for a glow plug of a diesel engine, includes a sintered ceramic heater, which generates heat upon receiving an electric current, supported by an electrically insulating sintered ceramic body. The heater element includes a U-shaped cross-section outer portion integrally sintered with and covering a central portion. Each portion is formed of a sintered ceramic body of a mixture of electrically conductive ceramic powder having an average diameter of not more than 2 .mu.m and selected from the group consisting of MoSi.sub.2, WSi.sub.2, TiB.sub.2 and TiC, and 35-75 mol % of electrically insulating ceramic powder, e.g., Si.sub.3 N.sub.4. The central and outer portions have the same composition. However, in the central portion the average particle diameter of the conductive ceramic powder is equal to or larger than that of the insulating ceramic powder, whereas in the outer portion the average particle diameter of the conductive ceramic powder is not more than half that of the insulating ceramic powder. The specific resistance of the central portion is not less than 1.7 times as large as that of the outer portion so that the heat is generated by current flow through the outer portion of the ceramic heater.

Sintered ceramic electric heater with improved thermal shock resistance

A distributor having electrodes made of a sintered body composed of a composite material such that the distributor can suppress radio noises to thereby prevent electric interference. The material for the electrodes, the sintered body, is composed of 45-90 mol % of zinc oxide and 55-10 mol % of ferrite, which can suppress radio noises generated between the electrodes due to spark discharging. At the same time, the energy loss within such composite material is small and consumption of electrode can be restrained. Electrode durability is further improved by including bismuth oxide, manganese oxide and cobalt oxide in the electrode material. An ignition plug and electric discharge machine can also advantageously use the electrodes composed of such materials.

Material for high frequency suppression and distributor for combustion

A ceramic heater comprises a heat generator made of a conductive ceramic sintered body, a supporter made of an insulating ceramic sintered body for supporting the heat generator, and a metallic wire for supplying an electric current from an electrode to the heat generator. The heat generator is integrally covered with an unporous covering layer made of an insulating ceramic sintered body. The covering layer prevents the heat generator from being directly exposed to oil and water. The covering layer is made of, for example Si.sub.3 N.sub.4 or glass containing SiO.sub.2 as a main constituent into a thickness of not more than 1mm.

A ceramic heater having a heating element of a sintered mixture comprising alumina, titanium nitride and titanium carbide, is discribed. The heating element has a good oxidation resistance, and a relatively high temperature coefficient of resistance. The larger composition of titanium nitride acts to increase the temperature coefficient of resistance. The larger composition of alumina acts to prevent oxidation increase and to improve the sintering. The adequate composition of each ingredients can result in a suitable heating element for a ceramic heater.

In an exhaust gas cleaning apparatus a ceramic heating resistor has a lattice-shaped exhaust gas passage and is formed by extrusion. The ceramic heating resistor is fixed closely to the upper stream side of a filter which catches particulates contained in exhaust gas. This heating resistor is divided into a plurality of sections so that heating current is successively supplied to the divided sections.

Exhaust gas cleaning apparatus

A ceramic heater device has a housing section and a heating section. The heating section includes a sintered ceramic insulator attached to a metal housing and a U-shaped sintered ceramic heater body fixed to the insulator, so that the heater body is supported by the housing section by means of the insulator in order to avoid a direct connection between the metal housing and the heater body. As a result, heat generated at the heater body may not be transferred to the metal housing, and thereby the heat can be effectively used to ignite a mixture of air and fuel in an engine and a rigid and stable support of the heater body to the metal housing can be obtained.

Ceramic heater device

A ceramic heating element is held in a metal housing to be mounted on an internal combustion engine, so that the heating element is operated as a glow plug for igniting an air-fuel mixture. The ceramic heating element is formed of an electrode section housed in the housing and a heat generating section extending out of the housing, whereby the heat generating section is exposed to the mixture in an engine cylinder. The electrode and heat generating sections are divided into two portions, respectively, and both forward ends of divided heat generating portions are connected with each other, so that electric current flows from one of the electrode portions through the divided heat generating portions to the other electrode portion.

A ceramic heater having a heating element of a sintered mixture comprising alumina and titanium nitride and/or titanium carbide. The heating element has a specific resistance in a range from 10.sup.-4 to several .OMEGA.cm. The ceramic heater may have supporting substrates of insulating materials with which the heating element is covered. The ceramic heater can be used at a temperature above 1000.degree. C.

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Okazaki, Japan

Morihiro Atsumi