Denso Corporation

Naoto Hayashi

Makoto Toriyama

Satoru Nakayama

Akimitsu Sugiura

Kaori Doi

Daisuke Tanaka

Masahiro Ishitani

Takashi Oono

Daisuke Shimamoto

Kanechiyo Terada

Shunichi Takeda

Fumiaki Aoki

Hisaharu Morita

Nobuo Abe

Takeshi Fukazawa

Atsuya Mizutani

Hironao Yamaguchi

Yuuki Kondou

Yuuto Tamei

Kenta Kyouda

Kouji Andoh

Hiroshi Araki

Yuji Kaji

Yuuki Kawata

Masashi Irie

Kenechiyo Terada

Hikaru Takashima

A ground electrode for a spark plug includes a ground electrode body arranged to face a center electrode of the spark plug. The ground electrode includes a discharge portion mounted on the ground electrode body to face the center electrode with a spark gap between the discharge portion and the center electrode. The discharge portion is made of a platinum-based alloy of platinum, rhodium, and nickel. A first mass percent of the rhodium contained in the platinum-based alloy of the platinum, the rhodium, and the nickel is within a first range from 2 wt % to 20 wt % inclusive. A second mass percent of the nickel contained in the platinum-based alloy of the platinum, the rhodium, and the nickel being within a second range from 2.5 wt % to 12 wt % inclusive.

Ground electrode for spark plug and spark plug

In a method for manufacturing a spark plug, a space on a proximal end side of a center electrode in a shaft hole of an insulator is filled with first electrically conductive glass powder. A space on the proximal end side of the first electrically conductive glass powder in the shaft hole is filled with resistor composition powder. A space on the proximal end side of the resistor composition powder in the shaft hole is filled with second electrically conductive glass powder. The first electrically conductive glass powder, the resistor composition powder, and the second electrically conductive glass powder are sintered in the shaft hole. Prior to filling of the resistor composition powder, at least one of the insulator and the first electrically conductive glass powder is placed in an uncharged state, or the insulator and the first electrically conductive glass powder are placed in the same charged state.

Method for manufacturing spark plug with peripheral edge of proximal end surface of sealing distal-end layer prevented from significantly rising toward proximal end

A spark plug includes a housing, an insulator, a center electrode, and an earth electrode. The earth electrode has a gap-forming surface which forms a discharge gap between the gap-forming surface and a tip surface of the center electrode. The insulator includes an insulator protrusion protruding on the tip side of the housing in a plug axial direction. At least one of cross-sections passing through a plug center axis and parallel to the plug axial direction is referred to as an axial parallel cross-section. The outer peripheral surface of the insulator protrusion includes an insulator inclined surface extending inward toward the tip in the plug axial direction, in a straight line or a curve that is convex inward, in the axial parallel cross-section. In the axial parallel cross-section, a virtual straight line passing through both ends of the insulator inclined surface passes through the gap-forming surface.

Spark plug for internal combustion engines

An ignition apparatus for an internal combustion engine includes a center electrode, a ground electrode, an insulator, a housing, and an insulator protective wall portion. The ground electrode is disposed such that a discharge gap is formed between the ground electrode and the center electrode. The insulator holds the center electrode on an inner side of the insulator. The housing holds the insulator on an inner side of the housing. The insulator protective wall portion is arranged to surround an outer circumference side of a distal end portion of the insulator. A distal end of the insulator protective wall portion is positioned further towards a distal end side than a distal end of the insulator is and further towards a proximal end side than a distal end of the center electrode is. The insulator protective wall portion includes an inward protruding portion that protrudes towards a side surface of the center electrode.

Ignition apparatus for internal combustion engine

In a spark plug, a discharge gap is formed between a ground electrode and a central electrode. The ground electrode has a rod-shaped part and an opposing part. The opposing part faces the central electrode, and has a flat surface part and a slope surface part. The slope surface part is formed on a part of the opposing part in an extending direction of the ground electrode, and formed on the opposing part and gradually separated from the central electrode along a width direction of the opposing part. The spark plug has a ratio V/W within a range of 0.5&#x3c;V/W&#x3c;2.0. V indicates a length of the opposing part measured in a gap formation direction in which the central electrode, the discharge gap and the opposing part are arranged in order. W indicates a length of the opposing part in the ground electrode width direction.

Spark plug of internal combustion engine

An ignition apparatus inputs energy during a predetermined energy input period after the interruption of a primary electric current by an ignition switch and a discharge of an ignition plug caused by a secondary electric current. Moreover, the ignition apparatus includes a blow-off detection unit that detects, during the energy input period IGW after the start of the discharge by the ignition plug, occurrence of blow-off of the discharge. When the secondary electric current Idrops below a blow-off detection electric current threshold value Ibo at a time instant tbo in a 'second region' where it is impossible to perform a re-discharge after blow-off, the blow-off detection unit determines that blow-off has occurred and the ignition apparatus stops the energy input from an energy input unit to an ignition coil. By preventing unnecessary energy input, it is possible to suppress unnecessary electric power consumption and wear of electrodes of the ignition plug.

Ignition apparatus

An ignition control apparatus of the present embodiment controls operation of an ignition plug provided so as to ignite an air-fuel mixed gas. The ignition control apparatus is characterized in that the ignition control apparatus includes: an ignition coil provided with a primary winding which allows a current to pass as a primary current therethrough and a second winding connected to the ignition coil, an increase and a decrease in the primary current generating a secondary current passing through the secondary winding; a DC power supply provided with a non-ground side output terminal, the non-ground side output terminal being connected to one end of the primary winding so that the primary current is made to pass through the primary winding; a first switching element configured of a semiconductor switching element provided with a first control terminal, a first power side terminal, and a first ground side terminal, the semiconductor switching element controlling on and off states of current supply between the first power side terminal and the first ground side terminal based on a first control signal inputted to the first control terminal, the first power side terminal being connected to the other end side of the primary winding, the first ground side terminal being connected to a ground side; a second switching element configured of a semiconductor switching element provided with a second control terminal, a second power side terminal, and a second ground side terminal, the semiconductor switching element controlling on and off states of current supply between the second power side terminal and the second ground side terminal based on a second control signal inputted to the second control terminal, the second ground side terminal being connected to the other end side of the primary winding; a third switching element configured of a semiconductor switching element provided with a third control terminal, a third power side terminal, and a third ground side terminal, the semiconductor switching element controlling on and off states of current supply between the third power side terminal and the third ground side terminal based on a third control signal inputted to the third control terminal, the third power side terminal being connected to the second power side terminal of the second switching element, the third ground side terminal being connected to the ground side; and an energy accumulation coil configured of an inductor, the inductor being interposed in a power line connecting the non-ground side output terminal of the DC power supply and the third power side terminal of the third switching element, the energy accumulation coil accumulating energy therein in response to turning on of the third switching element.

Ignition control apparatus

An ignition device at least equipped with a DC power source, an ignition coil unit, a spark plug, an ignition switch, and an auxiliary power source, wherein the auxiliary power source is at least equipped with a discharge energy accumulating means, a discharge switch, and a discharge driver. The ignition device is further equipped with a secondary-current feedback controlling means comprising a secondary current detecting means for detecting a secondary current flowing during the ignition coil unit discharge period, and a secondary current feedback control circuit-for determining an upper limit and a lower limit for the secondary current from binary threshold values, and driving so as to open and close the discharge switch on the basis of the determination results. Furthermore, energy is introduced from the auxiliary power source without switching the polarity of the secondary current.

Ignition device

An ignition control device comprises: a first switching element having a power source side terminal connected to an other end side of a primary coil and a first ground side terminal connected to a ground side; a second switching element having a second ground side terminal connected to the other end side of the primary coil; a third switching element having a third power source side terminal connected to the second power source side terminal in the second switching element, and a third ground side terminal connected to the ground side; and an energy storage coil. The energy storage coil is an inductor interposed in an electric power line connecting a non-ground side output terminal in a DC power source and the third power source side terminal in the third switching element, and stores energy from the turning on of the third switching element.

An ignition device includes an ignition coil with a primary coil and a secondary coil, a spark plug with center and ground electrodes for discharge therebetween, and a voltage limiting circuit. The voltage limiting circuit limits voltage applied between the electrodes of the spark plug such that the voltage has an absolute value limited within a predetermined voltage limiting value. The voltage limiting value is differentiated from each other in first and second stages. The first stage is defined as a period in which an initial discharge peak ends, the initial discharge peak being initially generated by electric energy. The second stage is defined as a period after the end of the initial discharge peak. The voltage limiting value in the first stage is lower than the voltage limiting value in the second stage.

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Kariya, Japan

Naoto Hayashi