US3911307A - Spark plug - Google Patents

Spark plug Download PDF

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Publication number
US3911307A
US3911307A US483537A US48353774A US3911307A US 3911307 A US3911307 A US 3911307A US 483537 A US483537 A US 483537A US 48353774 A US48353774 A US 48353774A US 3911307 A US3911307 A US 3911307A
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US
United States
Prior art keywords
chamber
spark plug
central electrode
discharge chamber
electrode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US483537A
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English (en)
Inventor
Kenji Goto
Daisaku Sawada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Toyota Motor Corp
Original Assignee
Toyota Motor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Toyota Motor Corp filed Critical Toyota Motor Corp
Application granted granted Critical
Publication of US3911307A publication Critical patent/US3911307A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P19/00—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition
    • F02P19/02—Incandescent ignition, e.g. during starting of internal combustion engines; Combination of incandescent and spark ignition electric, e.g. layout of circuits of apparatus having glowing plugs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B1/00—Engines characterised by fuel-air mixture compression
    • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
    • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder

Definitions

  • a spark plug for electric ignition of the fuel-air mixture is disclosed, which spark plug is provided with a central positive electrode and an outer negative electrode facing the positive electrode via a sparking gap, and further comprises an electric insulator member for enclosing the sparking gap so that a discharge chamber is defined by the insulator member, said positive electrode and negative electrode, the discharge chamber being operable to produce plasma-like gas while discharging occurs between both said electrodes, and at least a nozzle is provided for said discharge chamber for enabling the plasma-like gas to jet into the fuel-air mixture.
  • the spark plug can be adapted for use in a spark ignition type internal combustion engine.
  • the present invention relates to a spark plug adapted for use in a spark ignition engine in order to ignite the fuel-air mixture by utilizing a spark discharge between the positive and negative electrodes of the spark plug.
  • the object of the present invention is to provide a spark plug which is capable of exhibiting an excellent ignition ability.
  • a spark plug for electric ignition of the fuel-air mixture which is provided with a central positive electrode and an outer negative electrode facing said positive electrode via a sparking gap, comprises an electric insulator member for enclosing the sparking gap so that a discharge chamber is defined by the electric insulator member and the positive and negative electrodes, said discharge chamber being operable to produce plasma-like gas while discharging is held between said both electrodes, and at least a nozzle is provided for said discharge chamber for enabling said plasma-like gas to jet into said fuel-air mixture.
  • FIG. 1 is a front elevation view of a spark plug with an electric circuit system, in part cross section, according to an embodiment of the present invention
  • FIG. 2 is a cross sectional view of the portion designated by an arrow P in FIG. 1;
  • FIG. 3 through FIG. 6 are partial cross sectional views of the other embodiments of the present invention, which respectively show only the portions corresponding to the portion P of FIG].
  • a spark plug is provided with a centrally positioned positive electrode (a central positive electrode) 10, a tubular insulator 11 for electrically isolating the central positive electrode 10, a threaded part 13 for enabling the mounting of the spark plug onto an engine, a plug holder 12, with a hexagonal head 14 for locking of the spark plug, a grounded or earth electrode (a negative electrode) 15 formed as one part with the plug holder 12 and disposed to be opposite to said central electrode, and a gasket 16.
  • a central positive electrode a central positive electrode
  • a tubular insulator 11 for electrically isolating the central positive electrode 10
  • a threaded part 13 for enabling the mounting of the spark plug onto an engine
  • a plug holder 12 with a hexagonal head 14 for locking of the spark plug
  • a grounded or earth electrode (a negative electrode) 15 formed as one part with the plug holder 12 and disposed to be opposite to said central electrode
  • a gasket 16 a gasket
  • the insulator 11 extends so as to enclose the sparking gap formed between the central plug 10 and the earth electrode 15. That is to say, a considerably small discharging chamber 17 enclosed by the central electrode 10, together with the grounded electrode 15 and the insulator 11, is formed.
  • This discharging chamber I7 is capable of serving to prevent diffusion of energy of the spark which is produced between both electrodes 10 and 15.
  • the energy of the high-tension spark allows the mixture within the chamber 17 to produce a plasma-like gas.
  • This plasmalike gas jets into the associated combustion chamber (not shown) through a nozzle 18 formed in the earth electrode 15. It should be noted that said nozzle 18, which allows said plasma-like gas to jet into the combustion chamber, also allows the mixture or the mixture containing residual gas to flow into the chamber 17 from the combustion chamber.
  • the spark plug of the present invention When the spark plug of the present invention is mounted onto an engine, the spark plug operates as follows.
  • the electrode 15 is grounded, and the central electrode 10 is connected to a hightension current generator H which is connected to a battery B.
  • a hightension current generator H which is connected to a battery B.
  • the breakdown of the electric current takes place between both electrodes while producing a high-tension spark.
  • a part of the energy of the high-tension spark is supplied to the mixture staying in the discharging chamber 17 so as to heat said mixture.
  • the discharging chamber 17 is formed as a spatially isolated chamber enclosed by the electrodes and 15, and by the insulator 11, the energy supplied to the mixture within the chamber 17 is completely prevented from being dif fused.
  • the mixture within the chamber 17 is subsequently supplied with the thermal energy of the spark, and is heated extremely rapidly.
  • the heated mixture within the chamber 17 is altered into said plasma-like gas due to the occurrence of partial ionization in the heated mixture.
  • the jetted plasma-like gas designated by the reference G in FIG. 2 includes therein a high thermal energy together with a high kinetic energy of positive ions and electrons which are contained in said plasma-like gas.
  • the plasma-like gas jetting from the discharging chamber 17 can effectively supply the high thermal energy to an extensive amount of the mixture staying in the combustion chamber of an engine, so that said extensive amount of said mixture is heated and ignited.
  • the energy of the spark. is effectively transmitted to the extensive amount of said mixture within the combustion chamber of an engine.
  • the flame propagation takes place according to the present invention, since in the combustion chamber, the flame of the mixture ignitedby the plasmalike gas is not cooled or extinguished by the electrodes of the spark plug or other cold elements because the flame production occurs in places far from the electrodes or other cold elements.
  • the sparking gap itself is contained in the small discharge chamber 17.
  • the spark discharge which takes place in the sparking gap is not affected by the flow velocity of the mixture in the combustion chamber.
  • a stable discharge can be maintained over a considerably long period, and the total amount of the energy of the spark is increased.
  • FIGS. 3 through 6 show the other embodiments of the present invention, respectively. It should be understood that each of these embodiments is provided with a structure similar to that of the embodiment of FIG. 1 except for the portion corresponding to the portion P of FIG. 1, and therefore FIGS. 3 through 6 show only the respective portions corresponding to said portion P of FIG. 1. Also, it should be noted that in FIGS. 3 through 6 like elements or like parts are designated by the same reference numerals as in FIG. 1.
  • FIG. 3 shows another embodiment of a spark plug which is provided with a precombustion chamber 19 formed in front of the nozzle 18 by an extension a of the earth electrode 15.
  • the precombustion chamber 19 is connected to the associated combustion chamber (not shown) of an engine through a through-hole 20 in the extension 15a.
  • plasma-like gas produced in the chamber 17 jets into the precombustion chamber 19 through the nozzle 18 in the same manner as described with reference to FIG. 2.
  • the mixture staying in the precombustion chamber 19 simultaneously ignites and burns.
  • FIG. 4 shows another embodiment, in which the distance designated as B between the central electrode 10 and the earth electrode 15, is rendered smaller than the length A of a longitudinally extended discharge chamber 17.
  • the distance 8 is kept small, the gradient of the potential between the electrodes 10 and 15 can be large and thus, at the beginning of the discharge between both electrodes, a corona discharge is easily produced without affecting the provision of insulator member 11 between'both electrodes. Therefore, dielectric breakdown between both electrodes occurs at a relatively low potential.
  • This fact enables the high-tension current generator H to employ its remaining output energy other than that used for the above-mentioned dielectric breakdown, as ignition energy, even if the current generator H can exert only a limited constant energy on its output.
  • the ignition energy of this embodiment can be larger than that of the embodiment shown in FIGS. 1 and 2.
  • FIG. 5 shows another embodiment in which a discharge space 17a has a larger volume compared to the discharge space 17 of the embodiment of FIG. 1.
  • the amount of the mixture occupying the discharge chamber 17a will be increased. Therefore, if the size of the nozzle 18 is kept equal to that of the nozzle 18 of the embodiment of FIG. 1, the plasma-like gas jetting from the nozzle 18 will be increased in its jetting velocity due to the increase in the amount of the mixture occupying the discharge chamber 17, so that the flame propagation within the combustion chamber of an engine will also be increased.
  • FIG. 6 shows another embodiment in which plural nozzles 18, 18a and 18b are provided with respect to a discharge chamber 17 having a considerably large volume.
  • the plasma-like gas jetting out of the discharge chamber 17 can contact a larger amount of the mixture within the combustion chamber than in the case of a single nozzle and as a result, uniform heating of the mixture within the combustion chamber is obtained so that a stable ignition can be attained with certainty.
  • the energy of the spark produced by the discharge between the electrodes of the spark plug can be effectively supplied to the mixture and therefore the ignition ability of the spark plug can easily and advantageously be raised in response to a raise in the spark energy.
  • the structure of the spark plug is not complex compared with that of the conventional spark plug, and as a result, an increase in the manufacturing cost will not be envolved.
  • spark plug according to the present invention is not limited to an internal combustion engine.
  • a spark plug for electric ignition of a fuel-air mixture of the type having an outer metal body including a cavity provided with a restricted opening at one end, a central electrode and insulating means for supporting the central electrode in the outer body with a ,tip of the electrode positioned within the cavity, the outer metal body serving as an outer electrode facing the central electrode via a sparking gap defined between the central electrode and the wall of the cavity, wherein the improvement comprises:
  • an electric and heat insulator member lining substantially the entire inner wall of the cavity in the outer body from the tip of the central electrode to at least adjacent to the restricted opening for enclosing the sparking gap so that an insulated discharge chamber is defined by said insulator member in conjunction with said central electrode and said outer eleccharge chamber through said nozzle and having a through hole to connect said second chamber with fuelair mixture outside of said spark plug.
  • a spark plug as claimed in claim 1 further comprising at least one additional nozzle opening from said discharge chamber to provide additional high speed jets of plasma-like gas for contacting a larger amount trode, said insulated discharge chamber being of fuel-air mixture outside the chamber.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Spark Plugs (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
US483537A 1973-09-05 1974-06-27 Spark plug Expired - Lifetime US3911307A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP48099137A JPS5049532A (enrdf_load_stackoverflow) 1973-09-05 1973-09-05

Publications (1)

Publication Number Publication Date
US3911307A true US3911307A (en) 1975-10-07

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ID=14239317

Family Applications (1)

Application Number Title Priority Date Filing Date
US483537A Expired - Lifetime US3911307A (en) 1973-09-05 1974-06-27 Spark plug

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US (1) US3911307A (enrdf_load_stackoverflow)
JP (1) JPS5049532A (enrdf_load_stackoverflow)
DE (1) DE2436896A1 (enrdf_load_stackoverflow)

Cited By (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071800A (en) * 1975-12-05 1978-01-31 Associated Engineering Limited Three electrode arc plasma flame ignition devices
US4087719A (en) * 1976-03-04 1978-05-02 Massachusetts Institute Of Technology Spark plug
US4337408A (en) * 1979-04-23 1982-06-29 Nissan Motor Co., Ltd. Plasma jet ignition plug
US4364342A (en) * 1980-10-01 1982-12-21 Ford Motor Company Ignition system employing plasma spray
US4388549A (en) * 1980-11-03 1983-06-14 Champion Spark Plug Company Plasma plug
US4487192A (en) * 1983-04-18 1984-12-11 Ford Motor Co Plasma jet ignition system
GB2147362A (en) * 1983-10-01 1985-05-09 Smiths Industries Plc Igniters for gas turbine engines
GB2147361A (en) * 1983-10-01 1985-05-09 Smiths Industries Plc Igniters for gas turbine engines
US4795937A (en) * 1985-12-13 1989-01-03 Beru Ruprecht Gmbh & Co. Kg Spark plug with combined surface and air spark paths
US5076223A (en) * 1990-03-30 1991-12-31 Board Of Regents, The University Of Texas System Miniature railgun engine ignitor
US5113806A (en) * 1991-03-04 1992-05-19 Rodart George H Bicatalytic igniter converter and processor for internal combustion engines
US5211142A (en) * 1990-03-30 1993-05-18 Board Of Regents, The University Of Texas System Miniature railgun engine ignitor
RU2118026C1 (ru) * 1997-12-30 1998-08-20 Каримов Рафаиль Хурматович Электродинамическая свеча зажигания
GB2323892A (en) * 1997-04-03 1998-10-07 Ford Motor Co Ignition coil and spark plug assembly
US6019077A (en) * 1998-06-29 2000-02-01 Gorokhovsky; Vladimir I. Spark plug for internal combustion engine
US6104130A (en) * 1996-02-16 2000-08-15 Alliedsignal Inc. Radial gap high thread spark plug
US6188558B1 (en) 1997-02-05 2001-02-13 Carlos Bettencourt Lacerda Internal combustion engine with rail spark plugs and rail fuel injectors
EP1788235A2 (en) 2005-11-22 2007-05-23 Ngk Spark Plug Co., Ltd. Plasma jet spark plug and ignition system
US8729782B2 (en) 2010-10-28 2014-05-20 Federal-Mogul Ignition Non-thermal plasma ignition arc suppression
CN103812012A (zh) * 2014-02-09 2014-05-21 大连理工大学 一种用于内燃机的等离子点火火花塞
CN109083797A (zh) * 2018-10-26 2018-12-25 大连民族大学 一种具有出气斜孔及多阳极结构的等离子体点火器
CN116557147A (zh) * 2023-07-10 2023-08-08 中国人民解放军空军工程大学 等离子体起爆装置、旋转爆震发动机及起爆方法
WO2024167510A1 (en) * 2020-08-07 2024-08-15 EcoPower Spark, LLC Spark plug with mechanically and thermally coupled center electrode
US12381374B2 (en) 2020-08-07 2025-08-05 EcoPower Spark, LLC Spark plug with electrode head shielding element

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5448220U (enrdf_load_stackoverflow) * 1977-09-10 1979-04-04
US4264844A (en) * 1978-09-29 1981-04-28 Axe Gavin C H Electrical igniters
JPH0272577A (ja) * 1988-09-06 1990-03-12 Honda Motor Co Ltd 内燃機関の点火プラグ
JP4685608B2 (ja) * 2005-11-22 2011-05-18 日本特殊陶業株式会社 プラズマジェット点火プラグ
JP2008186743A (ja) * 2007-01-31 2008-08-14 Denso Corp プラズマ式点火装置

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2687713A (en) * 1951-08-14 1954-08-31 Boeing Co Surface arc antechamber spark plug

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1410471A (en) * 1971-11-16 1975-10-15 Ass Eng Ltd Ignition devices

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2687713A (en) * 1951-08-14 1954-08-31 Boeing Co Surface arc antechamber spark plug

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4071800A (en) * 1975-12-05 1978-01-31 Associated Engineering Limited Three electrode arc plasma flame ignition devices
US4087719A (en) * 1976-03-04 1978-05-02 Massachusetts Institute Of Technology Spark plug
US4337408A (en) * 1979-04-23 1982-06-29 Nissan Motor Co., Ltd. Plasma jet ignition plug
US4364342A (en) * 1980-10-01 1982-12-21 Ford Motor Company Ignition system employing plasma spray
US4388549A (en) * 1980-11-03 1983-06-14 Champion Spark Plug Company Plasma plug
US4487192A (en) * 1983-04-18 1984-12-11 Ford Motor Co Plasma jet ignition system
GB2147362A (en) * 1983-10-01 1985-05-09 Smiths Industries Plc Igniters for gas turbine engines
GB2147361A (en) * 1983-10-01 1985-05-09 Smiths Industries Plc Igniters for gas turbine engines
US4795937A (en) * 1985-12-13 1989-01-03 Beru Ruprecht Gmbh & Co. Kg Spark plug with combined surface and air spark paths
US5076223A (en) * 1990-03-30 1991-12-31 Board Of Regents, The University Of Texas System Miniature railgun engine ignitor
US5211142A (en) * 1990-03-30 1993-05-18 Board Of Regents, The University Of Texas System Miniature railgun engine ignitor
US5113806A (en) * 1991-03-04 1992-05-19 Rodart George H Bicatalytic igniter converter and processor for internal combustion engines
US6104130A (en) * 1996-02-16 2000-08-15 Alliedsignal Inc. Radial gap high thread spark plug
US6188558B1 (en) 1997-02-05 2001-02-13 Carlos Bettencourt Lacerda Internal combustion engine with rail spark plugs and rail fuel injectors
GB2323892A (en) * 1997-04-03 1998-10-07 Ford Motor Co Ignition coil and spark plug assembly
RU2118026C1 (ru) * 1997-12-30 1998-08-20 Каримов Рафаиль Хурматович Электродинамическая свеча зажигания
US6019077A (en) * 1998-06-29 2000-02-01 Gorokhovsky; Vladimir I. Spark plug for internal combustion engine
EP1788235A2 (en) 2005-11-22 2007-05-23 Ngk Spark Plug Co., Ltd. Plasma jet spark plug and ignition system
US20070114898A1 (en) * 2005-11-22 2007-05-24 Satoshi Nagasawa Plasma jet spark plug and ignition system for the same
US7714488B2 (en) * 2005-11-22 2010-05-11 Ngk Spark Plug. Co., Ltd. Plasma jet spark plug and ignition system for the same
EP1788235A3 (en) * 2005-11-22 2011-11-23 NGK Spark Plug Co., Ltd. Plasma jet spark plug and ignition system
US8729782B2 (en) 2010-10-28 2014-05-20 Federal-Mogul Ignition Non-thermal plasma ignition arc suppression
CN103812012A (zh) * 2014-02-09 2014-05-21 大连理工大学 一种用于内燃机的等离子点火火花塞
CN103812012B (zh) * 2014-02-09 2017-08-22 大连理工大学 一种用于内燃机的等离子点火火花塞
CN109083797A (zh) * 2018-10-26 2018-12-25 大连民族大学 一种具有出气斜孔及多阳极结构的等离子体点火器
WO2024167510A1 (en) * 2020-08-07 2024-08-15 EcoPower Spark, LLC Spark plug with mechanically and thermally coupled center electrode
US12381374B2 (en) 2020-08-07 2025-08-05 EcoPower Spark, LLC Spark plug with electrode head shielding element
CN116557147A (zh) * 2023-07-10 2023-08-08 中国人民解放军空军工程大学 等离子体起爆装置、旋转爆震发动机及起爆方法
CN116557147B (zh) * 2023-07-10 2023-09-12 中国人民解放军空军工程大学 等离子体起爆装置、旋转爆震发动机及起爆方法

Also Published As

Publication number Publication date
DE2436896A1 (de) 1975-03-13
JPS5049532A (enrdf_load_stackoverflow) 1975-05-02

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