Nippondenso Co., Ltd.

Denso Corporation

Kozo Takamura

Yasuyuki Sato

Hiroyuki Murai

Kanji Higuchi

Kiyoaki Tanaka

Makoto Shirai

Akio Katoh

Ryoji Kondo

Keiji Kanao

Tsunenobu Hori

Nobuo Abe

Seiji Morino

Kaoru Kuzuoka

Yasuhito Takasu

Hironori Osamura

Kenji Fukaya

Hiroya Ishiguro

Toshikazu Shimizu

Minoru Nagai

Taiji Yokoyama

Akihiko Mizutani

Masato Somiya

A ceramic heater is provided which may be built in a gas sensor to heat a sensor element up to a desired activation temperature. The ceramic heater includes a pair of electrical conductors formed on a ceramic body. Each of the conductors is equipped with a terminal. Leads are joined to the terminals for supplying electrical power to the conductors. Joints between the leads and the terminals are covered hermetically by a seal, thereby minimizing corrosion thereof to avoid disconnections of the terminals from the leads. This improves the durability of the ceramic heater.

Sealing structure of ceramic heater

A ceramic heater is provided which may be employed in a gas sensor. The ceramic heater includes a heating element disposed inside a ceramic body, a connector assembly, and a cover coating. The connector assembly consists of an external terminal, a connector terminal, and a metallic joint layer. The external terminal is affixed to an outer surface of the ceramic body in electrical connection with the heating element. The joint layer is formed on the external terminal to establish an electrical joint between the external terminal and the connector terminal. The cover coating is wrapped over a surface of the connector assembly and made of a metallic material containing a main component of one of Au, Pt, and Cr, thereby ensuring a corrosion resistance of the connector assembly.

Corrosion resistance structure of ceramic heater and gas sensor equipped with same

An improved structure of a spark plug which provides higher durability of a joint of a noble metal chip to an electrode such as a center or a ground electrode. The joint is formed by laser welding. A fused portion made of materials of the noble metal chip and the electrode fused together by the laser welding is formed in the joint so that it may continue over at least half a circumference of a contact between the noble metal chip and the electrode without interfaces of welds, thereby enhancing the activity of the fused portion as a thermal stress absorber. A welding method is also provided.

Structure of spark plug designed to provide higher durability and fabrication method thereof

In producing a spark plug including a central electrode having a first chip including noble metal and an earth electrode having a second chip including the noble metal, a spark gap being disposed between the first and second chips, a chip including the noble metal. The chip is welded to an end of the central electrode and to an end of the earth electrode. The welded chip is cut to form the first and second chips and the spark gap.

Method of producing a spark plug

A temperature sensor has a sensing element ( ) consisting of a thermistor ( ) and leads ( ) and a sheath pin ( ) containing core wires ( ), to accurately detect temperature. A method of manufacturing such a temperature sensor includes the steps of connecting the leads to the core wires, arranging an insulator ( ) around the sensing element, filling the insulator with an inorganic adhesive ( ) to fix the sensing element in the insulator, arranging a metal cover ( ) around the insulator, and joining an end of the metal cover to an end of the sheath pin.

Temperature sensor and method of manufacturing same

A spark plug for use in an internal combustion engine comprises a central electrode made of a base metal and an earth electrode. A tip portion is provided on the central electrode. The tip portion includes a noble metal tip layer for defining a spark discharge gap between the noble metal tip layer and the earth electrode, and an alloy layer provided between the noble metal tip layer and the central electrode. The tip portion is provided with grooves to be divided into a plurality of sections. The tip portion has an outer peripheral wall flared towards the earth electrode, and a width of the grooves gradually increases from a bottom thereof to a surface of the noble metal tip layer for defining the shark discharge gap.

Spark plug for internal combustion engine

A spark plug which realizes reliability against thermal stress even in a case where dissimilar noble metal materials are disposed on the tip portion of the center electrode opposing the ground electrode and which realizes improved productivity while assuring durable reliability. The spark plug includes a center electrode electrically insulated from a housing and having a small-diameter portion at a tip portion which has a diameter smaller than that of a main body of the center electrode and composed of similar kinds of material as the center electrode, and a round-shape material, which is formed into a cylindrical or a ring shape, composed of dissimilar metal material. The round-shape material is fitted to the small-diameter portion of the center electrode so as to form a minute clearance between an inner surface of the round-shape material and is fixed to the center electrode by a large diameter portion which is integrally formed on a tip portion of the center electrode such that the minute clearance is kept between the round-shape material and the center electrode.

Spark plug and method of producing the same

According to the present invention, a spark plug for an internal combustion engine includes a center electrode, a ground electrode so as to form a spark gap with the center electrode, and a tip electrode composed of a material having a superior consumable resistance as compared to the center electrode and disposed on an end face of the center electrode so as to form a spark gap with the ground electrode. An axial length of the discharge portion of the ground electrode where spark discharge occurs is substantially larger than an axial length of the tip electrode where spark discharge occurs. When used for an internal combustion engine, a spark discharge is mainly generated between the peripheral surface of the center electrode and the ground electrode during early operation. Consequently, as the center electrode has been consumed, the spark discharge is mainly generated between the tip electrode and the ground electrode. Therefore, the frequency of the spark discharge with the center electrode is lowered, and a low required voltage is maintained.

Spark plug having horizontal discharge

A spark discharge tip, such as for a spark plug for an internal combustion engine in which the life of the tip is prolonged. A composite material is formed by bonding a material for a discharge layer, mainly composed of platinum, to a material for a thermal stress relieving layer, which is an alloy mainly composed of platinum, and having a coefficient of thermal expansion between that of the electrode and that of the discharge layer. A composite tip is formed by stamping the composite material into a columnar shape from the discharge layer side so that the periphery of the interface between the discharge layer and stress relieving layer is covered by the discharge layer. The composite tip is then resistance welded to the electrode.

Spark electrode having low thermal stress

There is disclosed a spark plug which can maintain a low spark voltage for a long period of time even if a noble metal tip is used in a small amount. A discharge gap is formed between a central electrode and an earth electrode. The noble metal tip is formed on that end face of the central electrode facing the earth electrode. A cross-shaped groove is formed in that end face of the noble metal tip joined to the central electrode. The cross-shaped groove is exposed when the noble metal tip is consumed by a discharge developing in the discharge gap.

Long life spark plug having consumable discharge member

A spark plug for use in an internal combustion engine comprises a central electrode made of a base metal and an earth electrode. A tip portion is provided on the central electrode. The tip portion includes a noble metal tip layer for defining a spark discharge gap between the noble metal tip layer and the earth electrode, and an alloy layer provided between the noble metal tip layer and the central electrode. The tip portion is provided with grooves to be divided into a plurality of sections. The tip portion has an outer peripheral wall flared towards the earth electrode, and a width of the grooves gradually increases from a bottom thereof to a surface of the noble metal tip layer for defining the spark discharge gap.

Spark plug for internal combustion engine with recess in electrode tip

A spark plug for an internal combustion engine includes a central electrode, and an earth electrode disposed in opposed relation to the central electrode on an axis of the central electrode to thereby form a spark gap between the central electrode and the earth electrode. The central electrode has a pillar-like portion provided at a distal end thereof disposed close to the spark gap, the pillar-like portion having a predetermined thickness corresponding to an intended lifetime of the spark plug. The central electrode also has a smaller-diameter portion disposed adjacent to a proximal end of the pillar-like portion, the smaller-diameter portion being smaller in diameter than the pillar-like portion. The pillar-like portion and the smaller-diameter portion are interconnected in a step-like manner. A step portion may be provided between the pillar-like portion and the smaller-diameter portion so as to limit the position of a spark discharge. The central electrode may have a pillar-like shape, in which case the central electrode is radially inwardly reduced intermediate opposite ends thereof to form the smaller-diameter portion, so that the distal end portion of the central electrode disposed close to the earth electrode is formed into the pillar-like portion.

Spark plug for internal combustion engine with pillar shaped electrode

A spark plug for an automotive internal combustion engine providing improved ignition even when carbon is deposited on the insulator of the plug. A rich fuel-air ratio causes carbon to be deposited on spark plug insulators, thereby decreasing its effective insulation. By limiting the geometrical dimension of the plug's center electrode the problem of carbon build-up is overcome. The sizes of these elements have certain allowable ranges that enhance the igniting effect of the plug.

Spark plugs for internal-combustion engines

A spark plug for an automotive internal combustion engine providing improved ignition even when carbon is deposited on the insulator of the plug. A rich fuel-air ratio causes carbon to be deposited on spark plug insulators, thereby decreasing its effective insulation. By limiting the geometrical dimension of the plug's center electrode, ground electrode, and insulator the problem of carbon build-up is overcome. The sizes of these elements have certain allowable ranges that enhance the igniting effect of the plug.

Spark plug for internal-combustion engine

An ignition system of multispark type having an ignitability superior to that of a combination an ignition system of capacitor discharge type and a multispark system is disclosed. A first control signal is generated for turning on a first switching device a predetermined time before an ignition timing to store energy in an energy storage coil and turning off the first switching device at the ignition timing. A multispark control signal is generated for turning on a second switching device from the ignition timing and turning on and off the first and second switching devices alternately for a predetermined spark period. A second control signal is generated for turning on the first switching device upon the turning off of the second switching device to store energy in the energy storage coil and then turning off the first switching device to charge a capacitor with the energy stored in the energy storage coil.

Growing community of inventors

Nagoya, Japan

Kozo Takamura