Denso Corporation

Tomoyuki Watanabe

Ryohei Akiyoshi

Ken Hanashi

Hiroshi Araki

Masamichi Shibata

Hirofumi Suzuki

Kenji Hattori

Yasuomi Imanaka

Ryuichi Ohno

Toshiya Nakamura

Shin Hase

A spark plug which is capable of further improving load life performance and a resistor material for a spark plug are provided. A spark plug includes a center electrode, a terminal fitting, and a resistor disposed between the center electrode and the terminal fitting. The resistor contains glass, a zirconia-based material and an electrically conducting material. The zirconia-based material contains at least stabilized zirconia.

Spark plug and resistor material for spark plug

When one of a center chip and a ground chip of a spark plug is defined as a first chip and another one is defined as a second chip, a discharge starting ridge line, which is a straight ridge line that forms a boundary between two surfaces having different normal line directions, is formed in a portion closest to the second chip in the first chips, and a distance from the discharge starting ridge line to the second chip is configured to be equal at a portion where the first chip and the second chip are opposed to each other.

Spark plug

Disclosed herein is a spark plug capable of suppressing electrode consumption caused by a spark discharge and a method of manufacturing the same. A section except a welded section formed by welding a tip surface of a center electrode is defined as an unwelded section in side surfaces of a center chip, and a length of the unwelded section along a center axis of the center chip is defined as an unwelded section length. Under this definition, the welded section is formed in order for an unwelded section length in a side surface opposite to an inclination direction side of the center chip in the center chip to become longer than an unwelded section length in a side surface of the inclination direction side of the center chip in the center chip.

Spark plug and manufacturing method thereof

A spark plugincludes a cylindrical housing, a cylindrical insulator, a center electrode, a terminal bracket, a ground electrode, and a resistor. The insulator is held on the inside of the housing. The center electrodeis held on the inside of the insulator, with a tip end being projected therefrom. The terminal bracket is held on the inside of the insulator, with a base end part and being projected therefrom. The ground electrode forms a spark discharge gap G between itself and the center electrode. The resistor contains carbon and is disposed on the inside of the insulator so as to be located between the center electrodeand the terminal bracket. In an axial direction X of the spark plug, the resistor has a higher carbon content in a first region positioned on a tip side, compared to a second region positioned on a base end side.

Spark plug for internal combustion engine

In the spark plug, at least one of the center chip and the ground chip is bonded with a center electrode or a ground electrode. The selected chip has a first part formed so as to linearly extend along a first center axis of an electrode bonded with the first part and a second part formed so as to extend linearly from a tip end of the first part along a second central axis inclined with respect to the first central axis.

Ignition control system

The spark plug has a shaft shaped center electrode, insulator, terminal fitting, ground electrode and resistor. The insulator has an axially penetrating shaft hole, and the center electrode is held in a tip end side of the shaft hole. The terminal fitting has a shaft and a terminal part. The shaft is held in a base end side of the shaft hole. The terminal part is projected from a base end of the shaft hole to a base end side of the spark plug. The ground electrode faces the center electrode in a tip end side of the shaft hole. The resistor is disposed between the center electrode and the terminal fitting in the shaft hole. An axial length L of the resistor is 15 mm&#x2266;L&#x2266;22.5 mm. An axial length T of the shaft satisfies a relation of 1.25&#x2266;T/L.

Growing community of inventors

Kariya, Japan

Tomoyuki Watanabe