# US 4,396,855 A · Plasma jet ignition plug with cavity in insulator discharge end

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- Number: US 4,396,855 A
- Document ID: US4396855A
- Status: Granted
- Kind: A
- Application number: 06/158,910
- Filed: 1980-06-12
- Granted: 1983-08-02
- Earliest claimed: 1979-06-18
- Assignees: Nissan Motor Co., Ltd.
- Inventors: Iwao Imai; Masazumi Sone
- Web page: https://patentgrep.com/patent/US4396855A

## CPC

- H01T 13/39: Selection of materials for electrodes
- F02P 9/007: {by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition}
- H01T 13/50: having means for ionisation of gap (H01T13/52 takes precedence)
- H04N 2005/91314: {the copy protection signal being a pulse signal inserted in blanking intervals of the video signal, e.g. pseudo-AGC pulses, pseudo-sync pulses}
- H01T: SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES (overvoltage protection circuits H02H)
- F02P: IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES ({anti-pollution means for internal-combustion engines F02B17/00}; specially adapted for rotary-piston or oscillating-piston engines F02B53/12; {ignition of gas turbine plants F02C7/26; ignition of jet propulsion plants F02K9/95; starting of combustion engines F02N9/00}; ignition of combustion apparatus in general, glowing plugs F23Q; measuring of physical variables in general G01; controlling in general G05; data processing in general G06; electrical components in general see Section H; {ignition coils H01F38/12}; sparking plugs H01T13/00)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A plasma jet ignition plug comprises an electric insulator formed with a discharge cavity and a plurality of electrodes communicating with the discharge cavity to form, within the discharge cavity, a spark gap. The plurality of electrodes include a central electrode connected to a high voltage electric source and a low voltage electric source, and a peripheral electrode which is grounded. The peripheral electrode substantially closes the discharge cavity and is formed with a jet opening. At least that part of at least one of the plurality of electrodes which communicates with the discharge cavity is made of a material selected from a group consisting of ferrite, a nickel alloy containing at least one of silicon, aluminum and magnesium, and electrically conductive ceramic.

## Claims

### Claim 1

A plasma jet ignition plug comprising:
an electric insulator formed with a discharge cavity; and
a plurality of electrodes communicating with said discharge cavity to form, within said discharge cavity, a spark gap;
said plurality of electrodes including a central electrode connected to a high voltage electric source circuit and a low voltage electric source circuit, and a peripheral electrode connected to the ground, said peripheral electrode substantially closing said discharge cavity and being formed with a jet opening, and
wherein at least a portion of at least one of said plurality of electrodes is made from ferrite.

### Claim 2

A plasma jet ignition plug comprising:
an electric insulator formed with a discharge cavity; and
a plurality of electrodes communicating with said discharge cavity to form, within said discharge cavity, a spark gap;
said plurality of electrodes including a central electrode connected to a high voltage electric source circuit and a low voltage electric source circuit, and a peripheral electrode connected to the ground, said peripheral electrode substantially closing said discharge cavity and being formed with a jet opening; and
wherein at least a portion of at least one of said plurality of electrodes is made from a nickel alloy containing more than one of a group consisting of silicon in the range of 3 to 7 percent; aluminum in the range of 2 to 10 percent; and magnesium in the range of 1 to 15 percent.