Jidosha Kiki Co., Ltd.

Hitachi Metals, Ltd.

Takashi Aota

Koji Hatanaka

Seiji Okazaki

Hirohisa Suwabe

Mitusuke Masaka

Kenji Maruta

Minoru Masaki

Shigeki Yokoyama

Makoto Imaizumi

A glow plug for a diesel engine includes a heat generating coil, a control coil, a sheath, an electrode rod, and a housing. The heat generating coil serves as a heater element. The control coil is connected in series with the heat generating coil and serves as a controller for controlling power supply to the heat generating coil. The control coil has a positive temperature coefficient of resistance larger than that of the heat generating coil. The sheath accommodates the heat generating coil and the control coil to be embedded in a heat-resistant insulating powder. The sheath has an elongated small-diameter portion on a distal end side thereof and a large-diameter portion on a rear end side thereof. The heat generating coil is connected to an inner wall of a distal end of the small-diameter portion of the sheath. The electrode rod has a distal end portion to which one end of the control coil is connected. The housing supports a rear end portion of the sheath on the distal end side thereof, and the electrode rod. The heat generating coil is disposed in a distal end portion of the small-diameter portion of the sheath, and the control coil is disposed to extend from the small-diameter portion to the large-diameter portion of the sheath.

Glow plug for diesel engine with ptc control element disposed in

In a glow plug, a resistance element buried in an elongated, rod-like insulating ceramic member includes first and second resistive heating elements. The first heating element is arranged at the front end portion of a ceramic heater and made of a positive temperature coefficient resistive ceramic material, containing silicon nitride, such as SiAlON. The second heating element is arranged behind of and connected in series with the first heating element and made of a metal material (e.g., tungsten) having a positive temperature coefficient of resistance larger than that of the first heating element. Both heating elements are arranged in the portion of the ceramic member projecting outwardly from the holder and metal pipe fitted about the control portions of the ceramic member. The glow plug further comprises a metal holder holding the rod-like member in a way that a front portion of the rod-like member protrudes from the metal holder. The metal holder is substantially tubular and includes a metal pipe fitted on and fixed at a central portion in a longitudinal direction of the rod-like member, and is connected to the second heating element.

Glow plug with dual, dissimilar resistive heating elements in ceramic

A sheath heater is formed by connecting first and second helical resistive elements having different positive resistance temperature coefficients in series, and incorporating the first and second resistive elements in a sheath such that the two resistive elements are embedded in a heat resistance electric insulating powder. The sheath diameter of a sheath portion in which the first resistive element is embedded is set to be smaller than that of a sheath portion in which the second resistive element is embedded. In addition, the first and second resistive elements are connected to each other, through connecting ends extending to be located within the outer diameter of the first resistive element, within a gap larger than the sheath diameter of the sheath portion in which the first resistive element is embedded.

Temperature controlled glow plug having controlled saturation and

A glow plug for diesel engines in which a ceramic heater is supported, with the one end thereof cantilevered toward the outside, by the tip of a hollow holder ceramic heater is composed of a U-shaped heating portion and a pair of leads extending backwards from both ends of the U-shaped heating portion, both being formed integrally by an electrically conductive ceramic material. The outer periphery of at least one of the leads is bonded and held in the holder via an insulating layer. The rear end of the other of the leads is connected by a metallic lead wire to an external connection terminal. The ceramic heater and other component members are bonded integrally by a bonding material containing a reactive metal.

Glow plug for diesel engines

A sheath heater includes a metal sheath, a coil-like heater, and a heat-resistant insulating powder. The starting form of the metal sheath has a small-diameter cylindrical portion at its distal end and is formed to have a substantially tubular shape as a whole. The heater is fabricated by inserting the coil-like heater in the sheath. The heat-resistant insulating powder is charged in the sheath and holds the coil-like heater in the sheath so that the coil-like heater is electrically insulated from the sheath. The distal end portion of the sheath is melted and so that the confronting end of the coil-like heater is buried so as not to be exposed on the outer wall of a closing portion at the distal end of the sheath. The melting of the sheath end can be done by using plasma, electron-beam or laser welding techniques.

Metallic sheath heater with improved electrical connection between coil

A ceramic heater type glow plug includes a U-shaped ceramic heater consisting of a resistive ceramic material, a hollow metal holder, an external connecting terminal, a power control resistor, and a connecting unit. The hollow metal holder has a distal end portion for supporting the ceramic heater via insulating members. The external connecting terminal is insulatingly supported at a rear end of the metal holder. The power control resistor is arranged between one of terminal caps at a rear end side of the ceramic heater housed in the metal holder and the external connecting terminal and performs power supply control with respect to the ceramic heater. The connecting unit connects another one of the terminal caps at the rear end side of the ceramic heater to the metal holder. The power control resistor consists of a metal material having a larger positive resistance temperature coefficient than that of the resistive ceramic material constituting the ceramic heater. The connecting unit includes a hollow metal sleeve for insulatingly housing the power control resistor. The rear end of the metal sleeve is caulked to the rear end of the metal holder while the external connecting terminal is fitted in the metal sleeve via an insulating member.

Ceramic heater type glow plug

An energization control apparatus for a glow plug includes a battery, a glow plug, a power control unit, and an energization controller. The glow plug has a low rated voltage which allows rapid heating at a low battery voltage during cranking of a diesel engine in a severe wintertime condition. The power control unit is arranged between the battery and the glow plug to control a power supplied to the glow plug. The energization controller controls the power control unit so as to equalize a root-mean-square value of a voltage applied to the glow plug to be the low rated voltage when a voltage applied to the glow plug at the start of the diesel engine is detected to be higher than the low battery voltage.

Energization control apparatus for glow plug

A glow plug for a diesel engine includes a hollow holder, and a ceramic heater made of SiAlON extending through a distal end portion of the hollow holder and held by it. The ceramic heater is provided with a U-shaped heating element and a pair of lead portions extending backward from both ends of the U-shaped heating element and parallel to each other. The heating element and the pair of lead portions are integrally made of a resistive ceramic material. One of the lead portions is coupled to one end of an electrically conducting flexible wire, the other end of the wire being coupled to an external connecting terminal. A ration .epsilon.(.dbd.SH/SL) of cross-sectional areas SH of the U-shaped heating element to cross-section areas SL of the lead portions falls within the range of 0.15.ltoreq..epsilon..gtoreq.0.6.

Growing community of inventors

Saitama, Japan

Takashi Aota