Ngk Spark Plug Company, Limited

Hiroyuki Kimata

Masato Taniguchi

Chiaki Kumada

Takayuki Sakurai

Hideki Teramura

Takanori Mizuno

Shunsuke Gotoh

Seigo Muramatsu

Takaaki Asano

There is provided a control device for a glow plug, capable of controlling the energization of a resistance heater of the glow plug by a resistance control process while attaining good resistance control response under cooling of the heater by fuel injection and combustion gas and thereby stably controlling the amount of heat generated by the heater. The resistance heater includes a resistive heating element having a ratio of electrical resistance R1000 at 1000&#xb0; C. to electrical resistance R20 at 20&#xb0; C. of 6 or larger, and the glow plug is mounted with at least part of the resistive heating element being protrudingly located in an engine combustion chamber. Under such a condition, the control device controls energization of the resistance heater in a steady control mode to adjust electrical power supplied to the resistance heater in such a manner as to keep a resistance of the heater within a predetermined range.

Controller and glow plug for controlling energization modes

A heater includes a metallic shell, a heating element disposed at an end of the metallic shell, and a terminal electrode electrically connected to the heating element. The terminal electrode has a protruded portion protruding from the metallic shell. The protruded portion has a locking engagement section lockingly engageable with a connector for electrically connecting the terminal electrode to an outside for conduction of the heating element. A method of producing such a heater is also provided.

Heater and method of producing the same

A glow plug includes an inner pole and a ceramic heating rod disposed in and fixed to an outer shell at uppermost and lowermost pole fixed portions A, C and a heating rod fixed portion D. A ratio of L /L is larger than 2, where L is a distance from the lower end of the inner pole to the lower end of the fixed portion C; and L is a distance from the lower end of the inner pole to the lower end of the fixed portion A. A ratio of L /L is smaller than 15, wherein L is a distance from a middle point between the lower end of the inner pole and the upper end of the heating rod to the lower end of the fixed portion C; and L is a distance from the above middle point to the upper end of the fixed portion D.

Glow plug

A glow plug includes a metallic sleeve,; a cylindrical metallic shell,, which holds the metallic sleeve,; a terminal electrode,, which is attached into the cylindrical metallic shell,while being insulated therefrom; a ceramic heating member,, which is fitted into the metallic sleeve,; and a glass coating layer,. In the glow plug, a portion of an ion detection electrode,is exposed at the surface of an insulator,of the ceramic heating member,. The exposed portion is coated with a glass coating layer,, which is formed in such a manner as to extend all around the insulator,of the ceramic heating member,and has a thickness of 10-200 &mgr;m and a softening point of not lower than 600&deg; C.

Glow plug with glass coating over ion detection electrode

A heater main body (300) obtained by connecting one-side ends (331, 341) of lead-out tungsten wires (33, 34) having a metal deposit (301), e.g., silver, to the ends (321, 322) of a U-shaped heating resistor (32) is embedded in a ceramic powder. The powder containing the heater main body (300) embedded therein is press-molded into a given shape and then sintered by hot pressing to thereby obtain a ceramic heating element (3) in which the other ends (332, 342) of the lead-out wires are exposed on the surface of the resultant sintered body.

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Aichi, Japan

Hiroyuki Kimata