Nippondenso Co., Ltd.

Kabushiki Kaisha Toyota Chuo Kenkyusho

Nippon Soken, Inc.

Masami Oki

Osami Kamigaito

Hideyuki Masaki

Yasuo Nakamura

Minoru Ohta

Masatoshi Suzuki

Haruo Doi

Mitsuru Asano

Toshio Kandori

A resistor built-in spark plug comprising an insulator formed therein with an axially extending bore, a terminal nut fitted in an upper end portion of the bore, a center electrode fitted in a lower end portion of the bore, a resistor arranged in a central portion of the bore, one copper-glass electrode interposed between the resistor and the terminal nut, and another copper-glass electrode interposed between the resistor and the center electrode, such resistor being made by firing (calcining) and solidifying a resistor powder mixture consisting of 30 to 10 volume % of a principal resistor component containing tin oxide, 35 to 85 volume % of insulating ceramic filler powder of a higher electric resistivity than the principal resistor component which is selected from the group consisting of quartz glass, alumina, zircon, zirconia, silica (SiO.sub.2) and .beta.-spodumene, and 35 to 5 volume % of glass powder having a softening temperature in a range between 300.degree. and 600.degree. C. One or both of the two copper-glass electrodes may consist of two electrode layers, one copper-glass layer maintained in contact wth the resistor and having a higher copper content than the other copper-glass electrode layer.

Resistor built-in spark plug

A resistor built-in spark plug comprises an insulator formed with an axially extending inner hole, a stem fitted in the upper part of said hole in said insulator, a center electrode fitted in the lower part of said hole, a resistor disposed in the central part of said hole, and copper-glass electrode layers disposed between said resistor and said stem and between said resistor and said center electrode. Said resistor is made by firing and solidifying powder of resistor mixture consisting of 75 to 38 volume percent of main resistor component containing tin oxide and 25 to 62 volume percent of glass powder with softening temperature of 300.degree. to 600.degree.C. Said copper-glass electrode layers are made by firing and solidifying a mixture of copper powder and glass powder with the softening temperature of above 530.degree.C and more than 30.degree.C higher than the softening point of glass in the resistor portion.

A catalyst for purifying exhaust gas from vehicles comprises a monolithic carrier having a plurality of exhaust gas passages penetrating through the carrier, a layer of active refractory metallic oxide such as .gamma.-alumina, containing 1 to 20% by weight of a catalytic metal such as platinum deposited as first layer on inside surfaces of said plurality of the passages, and a layer of exhaust gas-permeable refractory metallic oxide such as .gamma.-alumina free from a catalytic metal deposited as an outermost layer further upon the first layer.

Catalyst for purifying exhaust gas from vehicles

Growing community of inventors

Nagoya, Japan

Masami Oki