Ngk Spark Plug Company, Limited

Keita Nakagawa

Tsutomu Shibata

Toshitaka Honda

Takao Kojima

Haruki Yoshida

Takayoshi Atsumi

Makoto Kuribayashi

Hiroshi Isomura

Kiyoteru Mori

Toru Furuichi

Tomohiro Iwatsuka

Masaru Kano

Yoshiki Inoue

Masahiro Yamamoto

The present invention provides spark plug that can improve detection accuracy of pre-ignition caused by flame kernel occurring inside spark plug. Terminal is located at a rear end side with respect to thread portion of metal shell. Detector electrode is provided at a portion located at a top end side with respect to a top end of contact portion between reduced diameter portion and shelf portion or packing in a space formed between outer periphery of insulator and inner periphery of the metal shell. The detector electrode and the terminal are connected by conductor. The detector electrode and the conductor are insulated from center electrode, the metal shell and ground electrode. Since the detector electrode is located in the space between the outer periphery of the insulator and the inner periphery of the metal shell, an early detection of the flame kernel occurring in this space can be possible.

Spark plug

Provided is a spark plug which allows a predetermined resistance to be imparted to a resistor with restraint of variation in resistance of the resistor and in turn, enables enhancement of yield. The spark plug includes a ceramic insulator having an axial hole extending in the direction of an axis CL, a center electrode, and a terminal electrode. A resistor is provided in the axial hole through sintering of a resistor composition which contains a conductive material such as carbon black, glass powder, and ceramic particles other than glass. As viewed on a section of the resistor taken along a direction orthogonal to the axis CL, 50% or more of sintered glass powder formed through sintering of the glass powder has a circularity of 0.8 or greater.

Spark plug for internal combustion engine

A spark plug () has a resistor () between a center electrodeand a metal terminal (). The resistor () contains glass, ceramic powder, an electrically conductive material, and metal. An average of two or more particles of the metal are present in an arbitrary region measuring 300 (&#x3bc;m)&#xd7;300 (&#x3bc;m) on an arbitrary section of the resistor (), and the total sectional area of the metal present in the region accounts for less than 1.6% of the region.

Spark plug and resistor composition

The present invention provides a technique of suppressing the generation of radio noise in a spark plug, wherein a high dielectric constant fixation-assisting member, formed of a high dielectric constant material which is higher in dielectric constant than alumina, is provided between a metallic shell and a second conductive portion CPwhich includes a metallic terminal of the spark plug

Spark plug having a fixation assisting member for the insulator

A spark plug having sufficient durability for an internal combustion engine can restrain a sharp increase in resistance of a resistor in spite of its reduced size. The spark plug comprises an insulator having an axial hole, a metallic shell provided on the outer circumference of the insulator, a center electrode inserted into a front end portion of the axial hole, a terminal electrode inserted into a rear end portion of the axial hole, and a ground electrode. A circular columnar resistor is disposed within the axial hole between the center electrode and the terminal electrode, thereby electrically connecting the center electrode and the terminal electrode. The resistor is composed of carbon black that serves as a conductive material, a glass powder, and ceramic particles. Each of the ceramic particles has a maximum particle size of 0.5 &#x3bc;m or less.

Spark plug for internal combustion engine and method of manufacturing the same

A gas sensor having a gas sensor element which includes: a reference electrode; a solid electrolyte layer having oxygen ion conductivity; a detection electrode; and an electrode-protecting layer covering the detection electrode. The electrode-protecting layer is a porous body carrying catalytic metal, and includes: a detection electrode side portion having a catalytic metal loading ratio of more than 0% by weight and not more than 0.005% by weight; and a surface side portion provided closer to the outer surface of the electrode-protecting layer than the detection electrode side portion, the surface side portion having a catalytic metal loading ratio of 0.01% by weight or more.

Growing community of inventors

Nagoya, Japan

Keita Nakagawa