Non-thermal equilibrium plasma ignition plug and non-thermal equilibrium plasma ignition device

Patent metadata

Field	Value
Publication number	US-9775227-B2
Application number	US-201514948910-A
Country	US
Kind code	B2
Filing date	Nov 23, 2015
Priority date	Dec 1, 2014
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A non-thermal equilibrium plasma ignition plug including a tubular metallic shell having an axial hole extending along an axial line, an insulator disposed in such a manner as to form a gap in cooperation with a wall surface of the axial hole at a forward end portion of the metallic shell, and a center electrode held at the center of the insulator, and generates nonequilibrium plasma in response to voltage applied thereto from a power supply. The insulator has a plurality of depressions or protrusions formed on a surface thereof which faces a discharge space therearound.

First claim

Having described the invention, the following is claimed:

1. A non-thermal equilibrium plasma ignition plug comprising:
a tubular metallic shell having an axial hole extending along an axial line;
an insulator disposed in such a manner as to form a gap in cooperation with a wall surface of the axial hole at a forward end portion of the metallic shell, said insulator held to the metallic shell; and
a center electrode held at the center of the insulator,
the non-thermal equilibrium plasma ignition plug generating nonequilibrium plasma in response to voltage applied thereto from a power supply,
wherein the insulator has a plurality of depressions or protrusions formed on a surface thereof which faces a discharge space therearound.

2. A non-thermal equilibrium plasma ignition plug according to claim 1 , wherein a surface area occupied by the plurality of depressions or protrusions has an occupancy rate of 20% or more, with that surface area of the insulator which faces the discharge space being taken as 100%.

3. A non-thermal equilibrium plasma ignition plug according to claim 2 , wherein the surface area occupied by the plurality of depressions or protrusions has an occupancy rate of 50% or less, with that surface area of the insulator which faces the discharge space being taken as 100%.

4. A non-thermal equilibrium plasma ignition plug according to claim 1 , wherein
the plurality of depressions or protrusions are a plurality of depressions, and the plurality of depressions satisfy a relational expression 0.6≦R/D≦2, where R is the circle equivalent radius of an opening end of each of the plurality of depressions, and D is the depth of each depression, or
the plurality of depressions or protrusions are a plurality of protrusions, and the plurality of protrusions satisfy a relational expression 0.6≦R/D≦2, where R is the circle equivalent radius of a bottom end of each of the plurality of protrusions, and D is the height of each protrusion.

5. A non-thermal equilibrium plasma ignition device comprising:
a non-thermal equilibrium plasma ignition plug including:
a tubular metallic shell having an axial hole extending along an axial line;
an insulator disposed in said metallic shell in such a manner as to form a gap in cooperation with a wall surface of the axial hole at a forward end portion of the metallic shell;
a center electrode held at the center of the insulator; and
a plurality of depressions or protrusions are formed on a surface and the insulator which faces a discharge space therearound; and

a high-voltage power supply which is an AC power supply for applying a predetermined high-frequency AC voltage to the non-thermal equilibrium plasma ignition plug, or a high-speed pulsed power supply for applying a high voltage to the non-thermal equilibrium plasma ignition plug a plurality of times in a pulse manner.

6. A non-thermal equilibrium plasma ignition device according to claim 5 , wherein the high-voltage power supply is the high-speed pulsed power supply, and the high-speed pulsed power supply applies a high voltage for an application time of 1 ns to 250 ns per cycle.

Assignees

• Ngk Spark Plug Co

Inventors

• Ban Kenji
• Kameda Hiroyuki
• Usami Kohei

Classifications

• H01T15/00

  Circuits specially adapted for spark gaps, e.g. ignition circuits (ignition circuits for internal-combustion engines F02P; electric spark ignition for combustion apparatus F23Q; protection circuits using spark gaps H02H9/06) · CPC title

• H01T13/52

  characterised by a discharge along a surface · CPC title

• H01T13/20 Primary

  characterised by features of the electrodes or insulation · CPC title

• H01T13/50

  having means for ionisation of gap (H01T13/52 takes precedence) · CPC title

• H05H1/52 Primary

  using exploding wires or spark gaps (H05H1/26 takes precedence) · CPC title