Plasma jet ignition plug
AssigneeNgk Spark Plug Co., Ltd.
InventorsHiroyuki Kameda, Naofumi Yamamura, Daisuke Kasahara
Life of this patent
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Abstract
An ignition plug that maintains excellent ignition performance over a long period of time through effective prevention of channeling. The ignition plug includes an insulator having an axial bore, a center electrode inserted into the axial bore, a metallic shell disposed externally of the outer circumference of the insulator, and a ground electrode fixed to a front end portion of the metallic shell. A cavity is defined by the wall surface of the axial bore and the front end surface of the center electrode. The ground electrode includes a body whose distal end portion is disposed away from the front end of the insulator, and a protrusion protruding from the body.
Claims14
A plasma jet ignition plug comprising:
- an insulator having an axial bore extending therethrough in a direction of an axis;
- a center electrode inserted into the axial bore in such a manner that a front end thereof is located rearward of a front end of the insulator with respect to the direction of the axis;
- a metallic shell disposed externally of an outer circumference of the insulator;
- and
- a ground electrode fixed to a front end portion of the metallic shell;
- a cavity being defined by a wall surface of the axial bore and a front end surface of the center electrode;
- wherein the ground electrode comprises
- a rodlike body configured such that a proximal end portion thereof is fixed to the front end portion of the metallic shell, an intermediate portion thereof is bent, and a distal end portion thereof is disposed away from and frontward of the front end of the insulator with respect to the direction of the axis, and
- a protrusion protruding from a surface of the body, and
- as viewed on an imaginary plane which is orthogonal to the direction of the axis and onto which an opening of the cavity and the protrusion are projected, a projected image of the opening of the cavity and a projected image of the protrusion overlap at least partially.
Dependencies are inferred from the claim text.