Ngk Spark Plug Company, Limited

Honda Giken Kogyo K.k.

Ngk Spark Pulg Co., Ltd.

Yoshihiro Matsubara

Shigeru Miyata

Hideji Yoshida

Yasuo Ito

Wataru Matsutani

Kazumasa Yoshida

Osamu Yoshimoto

Akio Kokubu

Takashi Suzuki

Makoto Yamaguchi

Yoshitaka Yamada

Hiroyuki Kameda

Junichi Kagawa

Hiroaki Kuki

Kozo Amano

Kazuya Iwata

Iwao Kunitomo

Masahiro Ishikawa

Shoichiro Ito

Akira Suzuki

Naomichi Miyashita

Kenji Nunome

Kenji Ishida

Hiroshi Ono

Takahiro Suzuki

Mamoru Musasa

Katsutoshi Nakayama

Takashi Hisaki

Yuuichi Shimasaki

Shuzo Matsumura

Masayuki Segawa

Kazuhiko Mori

Hironobu Mizutani

Kazumi Kawamura

Kiyotaka Ohno

Mamoru Kodera

Kenichi Hattori

Terumasa Tomita

Yuuji Hirano

Tetsushi Suzuki

Shinichi Hiramatsu

Yuji Hirano

Tetsusi Suzuki

Akio Kokubo

In a wire drawing process for forming a wire rod containing iridium as a main component and which further contains nickel and at least one of platinum, rhodium and ruthenium, and having a cross-sectional area of not smaller than 0.05 mmand not larger than 1.2 mm. The worked material is continuously heated red hot and/or white hot in a heating regionextending up to 60 mm from the work inserting surfacea of a diein a direction opposite that in which the workmoves, the work being heated to a temperature of 1000 to 1150&#xb0; C. at a temperature measuring positionwhich is removed from the work inserting surfacea by 20 mm. Furthermore, the temperature in the regionextending from the temperature measuring positionto the work inserting surfacea is set to not lower than 1000&#xb0; C., and the wire drawing rate is set to 300 to 1600 mm/min.

Method for manufacturing noble metal electric discharge chips for spark plugs

A spark plug including: a cylindrical insulator having an axial hole extending through the insulator in an axial direction; a center electrode inserted in the axial hole; a metal shell provided around an outer periphery of the insulator and having a leading end surface, from which a leading end surface of the insulator protrudes; a ground electrode having a base end bonded to the leading end surface of the metal shell; and a noble metal tip disposed on a distal end of the ground electrode, an end of the noble metal tip protruding toward the center electrode in a radial direction, wherein: the spark plug forming a spark discharge path upon application of a discharging voltage between the protruding end of the noble metal tip and an end of the center electrode, the spark discharge path including an aerial discharge gap between a part of the protruding end of the noble metal tip and a part of the end of the insulator and a surface-creeping discharge path beginning at a part of the end of the insulator and a part of the center electrode and extending along the end surface of the insulator; and the noble metal tip protruding from the leading end of the ground electrode by a protruding length of more than 0.2 mm.

Spark plug for internal combustion engine

There is provided a spark plug wherein an insulator and a metallic shell, when observed in a section made by a plane including an axis of a spark plug, have therebetween a gap of less than 0.45 mm at a more front end side than an engagement position of a packing and a first insulator stepped portion, and the gap is provided axially from a most front end side engagement position of the packing and a first insulator stepped portion as a starting point to a finishing point that is apart from the starting point by 1.2 mm or more toward the front end side while being apart from a front end surface of the metallic shell by 7.9 mm or more toward a rear end side.

Spark plug

An object of the invention is to provide a spark plug having a discharge portion made of a precious metal tip, in which peeling of the precious metal tip from a surface of the discharge portion can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the discharge portion can be suppressed.

Spark plug having a precious metal tip

A spark plug including a noble metal tip bonded to at least one of a front-end portion of a center electrode and an end portion of the ground electrode opposing the center electrode. The noble metal tip contains from 5 to 40 wt % of Rh; from 1 to 20 wt % of at least one of Ir, Re and Ru; from 0.2 to 3 wt % of Ni; and 37 wt % or more of Pt.

A spark plug including: a cylindrical metal shell; a cylindrical insulator fixed to the metal shell; a center electrode having its leading end protruding from a leading end of the insulator and its trailing end fixed to the insulator; and a ground electrode having one end fixed to the metal shell and forming a discharge gap between the ground electrode and the center electrode. The ground electrode includes a precious metal alloy portion containing: 50 weight % or more of a first component of one of Rh and Pt; less than 50 weight % of a second component of the other of Rh and Pt; and optionally a third component containing at least one of: Ni in an amount of less than 7 weight %; and Zr in an amount of less than 2 weight % the content of the third component being less than that of the second component.

Spark plug having ground electrode including precious metal alloy portion containing first, second and third components

An object of the invention is to provide a higher-durability spark plug provided with a center electrode and a side electrode. At least one of the center electrode and the side electrode includes a precious metal member facing a spark discharge gap between the electrodes. A sweating phenomenon of the precious metal member can be suppressed while spark abrasion, oxidation abrasion and abnormal abrasion of the precious metal member are suppressed. The precious metal member contains Ir as a main component, and smaller amounts of Rh, Ru, and Ni.

Spark plug with electrode including precious metal

In a wire drawing process for forming a wire rod containing iridium as a main component and which further contains nickel and at least one of platinum, rhodium and ruthenium, and having a cross-sectional area of not smaller than 0.05 mmand not larger than 1.2 mm. The worked material is continuously heated red hot and/or white hot in a heating regionextending up to 60 mm from the work inserting surfaceof a diein a direction opposite that in which the workmoves, the work being heated to a temperature of 1000 to 1150&#xb0; C. at a temperature measuring positionwhich is removed from the work inserting surfaceby 20 mm. Furthermore, the temperature in the regionextending from the temperature measuring positionto the work inserting surfaceis set to not lower than 1000&#xb0; C., and the wire drawing rate is set to 300 to 1600 mm/min.

A method of making a spark plug having a noble metal chip joined to an electrode main body of a ground electrode by interposing therebetween an intermediate member. The method comprises the steps of prior to joining the noble metal chip to the electrode main body, joining the intermediate member and the noble metal chip together, placing a noble metal chip and intermediate member assembly on the electrode main body in a way as to allow the intermediate member to contact the electrode main body, and welding the electrode main body and the intermediate member together while restricting relative movement of the electrode main body and the intermediate member without applying an urging force to a joint between the intermediate member and the noble metal chip.

Method of making a spark plug

Spark plug having resistance against smoldering, long lifetime, and excellent ignitability

A spark plug having a center electrode formed from an electrode base material , which is made of an Ni alloy containing an alloy component (e.g., Cr) capable of forming an oxide semiconductor having a resistivity of negative temperature coefficient. Thus, a corrosion suppression layer originating from the components of the electrode base material is formed on the surface of a tip end portion of the insulator so that corrosion (channeling) of the surface of the tip end portion of the insulator due to creeping spark discharge can be effectively suppressed. In addition, when the constituent metal of the electrode base material has a coefficient of thermal conductivity of 17 to 30 W/m&middot;K, the heat transfer performance of the electrode is enhanced, so that durability against electrode consumption can be greatly improved.

Spark plug with nickel alloy electrode base material

A spark plug includes a metallic shell having a stepped portion an insulator disposed inside the metallic shell, while being engaged with the stepped portion of the metallic shell, and having an axially extending through hole; a center electrode fixed within the through hole of the insulator; and a ground electrode having a tip end portion bent toward the center electrode to thereby form a spark discharge gap. The insulator is formed such that the outer diameter of the insulator decreases toward the tip end side from an engagement position at which the insulator engages the stepped portion and such that the diameter decreases stepwise at an axial position between the engagement position and the tip end of the insulator. The diameter reduction ratio Y &equals;D /d is 0.6 or less in a region of at least 2 mm extending from the tip end surface of the insulator toward the base end side, wherein D represents the outer diameter of the insulator measured at an arbitrarily determined axial position, and d represents the inner diameter of the tip end portion of the metallic shell. Further, a clearance ratio Y &equals;(d &minus;D )/d is 0.4 or greater in a region of at least 1 mm extending from the tip end surface of the metallic shell toward the base end side.

An ignition system has a spark plug and a positive voltage applying unit. The spark plug includes a central electrode, a porcelain insulator for holding the central electrode, a main metallic shell for holding the porcelain insulator, and a ground electrode electrically connected to the main metallic shell. The positive voltage applying unit applies a positive voltage to the central electrode of the spark plug in comparison with the ground electrode, so that an ignition high voltage is applied between the central electrode and the ground electrode. In the spark plug, a spark discharge gap is formed between the ground electrode and a distal end portion of the central electrode. The ground electrode is positioned so that a rear edge of a mating face opposed to a peripheral side of the central electrode is positioned in the side of the distal end of the central electrode in comparison with an end face of the porcelain insulator.

Ignition system

In the ignition apparatus for internal combustion engine according to the invention, during a period when spark discharge voltage is detected by a waveform detecting unit and an ignition coil supplies the spark discharge voltage by use of ignition detection ignition in each of cylinders is detected in accordance with discharged voltage by the waveform detecting unit When the ignition detection detects the ignition by use of, for example, an ignition control unit during a discharging period of supplying the spark discharge voltage having detected the ignition, the supply of the spark discharge voltage is stopped. Thereby, since the supply of the spark discharge voltage is stopped after having detected the ignition, it is possible to avoid the surplus supply of spark energy to the spark plug after having fired.

Apparatus and method for controlling ignition of an internal combustion engine

An ignition system for an internal combustion engine. At least one of a plurality of spark plugs and attached to each of cylinders A, B, B, and A is a self-cleaning spark plug A.

Ignition system for internal combustion engine

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Yokkaichi, Japan

Yoshihiro Matsubara