Plasma igniter and ignition device for internal combustion engine
AssigneeNGK Insulators, Ltd.
InventorNaohiro Shimizu
Life of this patent
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Abstract
To provide a plasma igniter capable of generating a discharge such as a pulse streamer discharge in a large region even by application of a low voltage, implementing powerful ignition by pulse voltage application in two or more stages, improving an air-fuel ratio (A/F), and reducing a CO2 emission amount. A plasma igniter includes an igniter part having a combustion chamber, and a discharge part arranged in such a manner that its discharge tip end is exposed to the combustion chamber. The discharge tip end has a column-shaped anode, an annular cathode arranged to be a predetermined interval away from an anode tip end part, and an annular floating electrode arranged between the anode tip end part and the cathode.
Claims8
An ignition device for an internal-combustion engine comprising:
- an electrode structure body comprising an anode, a cathode and a floating electrode;
- and
- a pulse power supply to apply a pulse voltage between said anode and said cathode;
- wherein:
- a discharge contributing part of said cathode is positioned to be a first distance away from a discharge end of said anode along a surface of said electrode structure body;
- a discharge contributing part of said floating electrode is positioned to be a second distance shorter than said first distance, away from the discharge end of said anode along the surface of said electrode structure body, and interposed between the discharge end of said anode and the discharge contributing part of said cathode;
- and
- said pulse power supply applies a relatively low pulse voltage between said anode and said cathode to generate a pulse discharge in a first discharge region between the discharge end of said anode and the discharge contributing part of said floating electrode, and then applies a relatively high pulse voltage thereto to generate a pulse discharge in a second discharge region between the discharge end of said anode and the discharge contributing part of said cathode.
An ignition device for an internal-combustion engine comprising:
- an electrode structure body comprising an anode, a cathode, a floating electrode and a dielectric barrier;
- and
- a pulse power supply to apply a pulse voltage between said anode and said cathode;
- wherein:
- a discharge contributing part of said cathode is positioned to be a first distance away from a discharge end of said anode along a surface of said electrode structure body;
- a discharge contributing part of said floating electrode is positioned to be a second distance shorter than said first distance, away from the discharge end of said anode along the surface of said electrode structure body, and interposed between the discharge end of said anode and the discharge contributing part of said cathode;
- said dielectric barrier is arranged between said anode and said floating electrode to shield the discharge contributing part of said cathode and the discharge contributing part of said floating electrode from the discharge end of said anode, and has an opening at a position so as not to hinder the shielding of the discharge contributing part of said cathode and the discharge contributing part of said floating electrode from the discharge end of said anode;
- and
- said pulse power supply applies a relatively low pulse voltage between said anode and said cathode to generate a pulse discharge in a first discharge region between the discharge end of said anode and the discharge contributing part of said floating electrode, and then applies a relatively high pulse voltage thereto to generated a pulse discharge in a second discharge region between the discharge contributing part of said floating electrode and the discharge contributing part of said cathode.
Dependencies are inferred from the claim text.