EP0800247A1 - Zweifacher Polarität-Zündsystem für eine Zündkerzengruppe - Google Patents

Zweifacher Polarität-Zündsystem für eine Zündkerzengruppe Download PDF

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Publication number
EP0800247A1
EP0800247A1 EP97302332A EP97302332A EP0800247A1 EP 0800247 A1 EP0800247 A1 EP 0800247A1 EP 97302332 A EP97302332 A EP 97302332A EP 97302332 A EP97302332 A EP 97302332A EP 0800247 A1 EP0800247 A1 EP 0800247A1
Authority
EP
European Patent Office
Prior art keywords
noble metal
spark plug
tip
center electrode
group
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.)
Granted
Application number
EP97302332A
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English (en)
French (fr)
Other versions
EP0800247B1 (de
Inventor
Yoshihiro Matsubara
Katsutoshi Nakayama
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.)
Niterra Co Ltd
Original Assignee
NGK Spark Plug Co Ltd
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 NGK Spark Plug Co Ltd filed Critical NGK Spark Plug Co Ltd
Publication of EP0800247A1 publication Critical patent/EP0800247A1/de
Application granted granted Critical
Publication of EP0800247B1 publication Critical patent/EP0800247B1/de
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
    • F02P15/00—Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 and combined with layout of ignition circuits
    • F02P15/02—Arrangements having two or more sparking plugs
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
    • H01T13/00—Sparking plugs
    • H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
    • H01T13/39—Selection of materials for electrodes

Definitions

  • the invention relates to a dual polarity type ignition system for a spark plug group in which a noble metal tip is secured to an electrode to advantageously improve a spark erosion resistance property, and particularly relates to a spark plug which is energized with a dual polarity type ignition device as a power source.
  • a row of spark plugs are categorically divided into two groups, one is a group in which a terminal is connected to a positive high voltage terminal of a secondary coil in an ignition coil, while the other is a group in which the terminal is connected to a negative high voltage terminal of the secondary coil in the ignition coil.
  • the structurally same spark plugs have been incorporated into the ignition device.
  • a Pt-related noble metal tip has been used to a firing portion of a center and ground electrode to exhibit a spark erosion resistant property.
  • a platinum spark plug in which the Pt-related metal tip is provided, it is possible to prevent a spark gap from inadvertently increasing due to the spattering action in which the firing portion would be spark eroded so that a part of the firing portion is gradually dissipated.
  • An experimental test result showed that the durability in terms of the spark erosion had been improved from approx. 30000 km to 100000 km.
  • the Pt-related noble metal is generally very expensive.
  • a ground electrode of the spark plug group in which the positive high voltage is applied to the center electrode is spark eroded faster than that in which the negative high voltage is applied to a center electrode.
  • the center electrode of the spark plug group in which the negative high voltage is applied to a center electrode is spark eroded faster than that in which the positive high voltage is applied to the center electrode.
  • the Pt-related metal tip is unacceptably eroded at an end of serviceable period in the ground electrode of the spark plug group in which the positive high voltage is applied to the center electrode, the Pt-related metal tip is slightly eroded in the ground electrode of the other spark plug group in which the negative high voltage is applied to the center electrode.
  • a first noble metal tip of a center electrode of a spark plug (positive polarity group) to which a positive high voltage is applied is spark eroded slower than that of a spark plug (negative polarity group) to which a negative high voltage is applied.
  • a second noble metal tip of a ground electrode of the spark plug (negative polarity group) in which the negative high voltage is applied to the center electrode is spark eroded slower than that of a spark plug (positive polarity group) in which the positive high voltage is applied to the center electrode.
  • the spark erosion resistant property is not affected substantially by making the first noble metal tip dimensionally smaller in which the positive high voltage is applied to the center electrode of the spark plug (positive polarity group) than that of a spark plug (negative polarity group) in which the negative high voltage is applied to the center electrode.
  • a first noble metal alloy tip of a center electrode of a spark plug (positive polarity group) to which a positive high voltage is applied is spark eroded slower than that of a spark plug (negative polarity group) to which a negative high voltage is applied.
  • a second noble alloy metal tip of a spark plug in which the negative high voltage is applied to the center electrode is spark eroded slower than that of a spark plug to which the positive high voltage is applied to the center electrode.
  • the spark erosion resistant property is not affected substantially by making a noble metal component of the first noble metal alloy tip smaller in which the positive high voltage is applied to the center electrode than that of a spark plug in which the negative high voltage is applied to the center electrode.
  • a negative high voltage is applied to the center electrode in the mono-gap type spark plug, while a positive high voltage is applied to the center electrode in the multi-gap type spark plug.
  • a noble metal tip or a noble metal alloy tip is secured to an elevational side of a front end of the center electrode to which the positive high voltage is applied.
  • the noble metal tip provided on the ground electrodes can be omitted because the spark erosion is shared by the pluralistic ground electrodes.
  • a noble metal tip is provided preferably on both the center electrode and the parallel type ground electrode to reduce the spark erosion of the center and ground electrode to which a negative and positive high voltage is in turn applied.
  • a first noble metal tip of a center electrode of a spark plug to which a positive high voltage is applied is spark eroded slower than a second noble metal tip of a ground electrode, and a second noble metal tip of a spark plug to which a positive high voltage is applied to a center electrode, is spark eroded slower than a first noble metal tip of a center electrode.
  • This also makes it possible to decrease an amount of the noble metal tip of the ground electrode of the spark plug in which the high negative voltage is applied to the center electrode more than that of the center electrode without losing a good spark erosion resistant property. This holds ture when no noble metal tip is provided on the ground electrode of the spark plug in which the high negative voltage is applied to the center electrode.
  • a first noble metal alloy tip of a center electrode of a spark plug to which a positive high voltage is applied is spark eroded slower than a second noble metal alloy tip of a ground electrode
  • a second noble alloy metal tip of a spark plug to which a positive high voltage is applied to a center electrode is spark eroded slower than a first noble metal tip of a center electrode
  • This also makes it possible to decrease an amount of the noble metal component of the ground electrode of the spark plug in which the high negative voltage is applied to the center electrode more than that of the center electrode without losing a good spark erosion resistant property. This holds ture when no noble metal alloy tip is provided on the ground electrode of the spark plug in which the high negative voltage is applied to the center electrode.
  • a noble metal tip is provided on the center electrode to which the negative high voltage is applied.
  • This also makes it possible to decrease an entire amount of the noble metal used to the multi-gap type spark plug so as to contribute to cost reduction without losing a good spark erosion resistant property.
  • the spark plug B (C) has a cylindrical metal shell 1 and an insulator 2 provided in the metal shell 1 in the manner to extend a front end 20 of the insulator 2 from a front end 11 of the metal shell 1.
  • the insulator 2 has an axial bore 21 in which a center electrode 4 is fixedly placed in the manner to extend its front end 41 from a front end 201 of the insulator 2.
  • a noble metal tip 3 is fixedly placed as described in detail hereinafter.
  • a parallel type ground electrode 6 is welded whose front inner side 61 has a noble metal tip 5 to form a spark discharge gap Gp with the noble metal tip 3 of the center electrode 4.
  • the spark plug B (C)thus structured is to be mounted on a cylinder head of an internal combustion engine (each not shown) via a gasket 131.
  • Numeral 71 shows a terminal electrode, numerals 72, 73 a glass sealant, numeral 74 a resistor element.
  • the denotation B represents the mono-gap type spark plug in which a negative high voltage is applied to the center electrode 4 (negative polarity side group), while the denotation C represents the mono-gap type spark plug in which a positive high voltage is applied to the center electrode 4 (positive polarity side group) according to the present and subsequent embodiments of the invention.
  • the denotation A it represents a comparable mono-gap type spark plug which has been used with no consideration taken about adjusting an amount of the noble metal depending on whether the center electrode 4 is in the negative or positive polaroty side.
  • the metal shell 1 is made of a low carbon steel whose outer surface 120 has a threaded portion 12.
  • the metal shell 1 further has a barrel portion 13 and a hexagon 14.
  • the barrel portion has the gasket 131 at the boundary with the threaded portion 12.
  • the hexagon 14 is used to mount the metal shell 1 on the cylinder head by means of a wrench.
  • the insulator 2 is made from a ceramic material with alumina as a main constituent, and having an insulator nose 22, a diameter-increased portion 23 and a tubular head 24 whose outer surface forms a corrugation portion 241.
  • the insulator nose 22 is surrounded by the threaded portion of the metal shell 1, and the diameter-increased portion 23 is surrounded by the barrel portion 13.
  • the axial bore 21 runs through an entire length of the insulator 2.
  • the insulator 2 is firmly placed in the metal shell 1 by resting a seat portion 221 on a tapered shoulder portion 123 of a ledge portion 122 of the metal shell 1 via a metallic packing 121.
  • the insulator 2 is stabilized by caulking a rear end fin 141 tightly against the insulator 2 to hermetically seal the insulator 2 by means of O-rings 142, 143 and a talc sealant 144.
  • the center electrode 4 is made of a nickel-based alloy in which a copper or silver metal core 40 is embedded.
  • the center electrode 4 has a flange portion 42 and an elongation portion 43 and a frusto-cone shaped portion 44 which extends forward from the elongation portion 43.
  • the noble metal tip 3 is fixedly placed on a front end surface of the frusto-cone shaped portion 44.
  • the center electrode 4 it includes a part of the elongation portion 43, the frusto-cone shaped portion 44, and the noble metal tip 3.
  • An extension of the center electrode 4 from the front end 201 of the insulator 2 is 1.5 mm in length, and the spark discharge gap Gp is 1.0 mm in width.
  • the noble metal tip 3 is made of Pt-based alloy containing 20 % Ir by weight, and having the following dimension.
  • the noble metal tip 3 measures 0.8 mm in diameter and 0.5 mm in thickess when referred to the mono-gap type spark plug B.
  • the noble metal tip 3 measures 0.6 mm in diameter and 0.2 mm in thickess when referred to the mono-gap type spark plug C.
  • the noble metal tip 3 measures 0.8 mm in diameter and 0.5 mm in thickess when referred to the mono-gap type spark plug A.
  • the parallel type ground electrode 6 is formed into L-shaped configuration whose front inner side 61 has the noble metal tip 5 to face a front end surface 31 of the noble metal tip 3 of the center electrode 4.
  • the noble metal tip 5 is made of Pt-based alloy containing 20 % Ir by weight in the same component of the noble metal tip 3, and having the following particulars.
  • the noble metal tip 5 measures 0.5 mm in diameter and 0.2 mm in thickess when referred to the mono-gap type spark plug B.
  • the noble metal tip 5 measures 0.9 mm in diameter and 0.4 mm in thickess when referred to the mono-gap type spark plug C.
  • the noble metal tip 5 measures 0.9 mm in diameter and 0.4 mm in thickess when referred to the mono-gap type spark plug A.
  • a spark erosion resistance experimental test was carried out to compare the mono-gap type spark plug B (C) to a mono-gap type spark plug H in which no noble metal tip (3, 5) was provided.
  • the spark discharge gap and the raw material of the mono-gap type spark plug H is the same as those of mono-gap type spark plug B (C) except that no noble metal tip is provided with the mono-gap type spark plug H which has a straight type center electrode (2.5 mm in dia.).
  • the spark plugs A, B, C, H were mounted on a 3000 cc, V-type six-cylinder engine with the use of dual polarity type ignition device (DLI) in a dual polarity type ignition system to run the engine at 5500 rpm ⁇ W.O.T. (full throttle condition) in the following combination.
  • DPI dual polarity type ignition device
  • Fig. 5 shows an amount of the noble metal used to each of the spark plugs A, B, C.
  • the amount of the noble metal used to the spark plug A is converted to 1.0, the amount of the noble metal used to the spark plugs B and C in turn come approximately to 0.57 and 0.61.
  • the noble metal tip needs only 59.5 % of the noble metal used when the mono-gap type spark plug A is uniformly adopted. This makes it possible to reduce the price of the product without losing a good spark erosion resistanct property which is insured substantially when the mono-gap type spark plug A is uniformly used.
  • Figs. 1 and 2 which also depict mono-gap type spark plug B2 (C2) according to a second embodiment of the invention
  • the center electrode 4 in the mono-gap type spark plug B2 (negative polarity group) is in the negative polarity side
  • the center electrode 4 in the mono-gap type spark plug C2 (positive polarity group) is in the positive polarity side.
  • the spark discharge gap and the raw material of the mono-gap type spark plug B2 (C2) is the same as those of mono-gap type spark plug B (C).
  • the noble metal tip 3 measures 0.8 mm in diameter and 0.5 mm in thickness.
  • the noble metal tip 3 is made of Pt-based alloy having the following constituent.
  • the Pt-based alloy contains 5 % nickel by weight when referred to the mono-gap type spark plug B2.
  • the Pt-based alloy contains 20 % nickel by weight when referred to the mono-gap type spark plug C2.
  • the Pt-based alloy contains 5 % nickel by weight when referred to the mono-gap type spark plug A2.
  • the noble metal tip 5 has the same material as the noble metal tip 3, and measures 0.9 mm in diameter and 0.4 mm in thickness.
  • the noble metal tip 5 is made of Pt-based alloy having the following constituent.
  • the Pt-based alloy contains 30 % nickel by weight when referred to the mono-gap type spark plug B2.
  • the Pt-based alloy contains 10 % nickel by weight when referred to the mono-gap type spark plug C2.
  • the Pt-based alloy contains 10 % nickel by weight when referred to the mono-gap type spark plug A2.
  • spark erosion resistance experimental test was carried out in the same manner as described in the first embodiment of the invention.
  • the spark plugs B2, C2, A2 were mounted on a 3000 cc, V-type six-cylinder engine with the use of a dual polarity type device in a dual polarity type ignition system to run the engine at 5500 rpm ⁇ W.O.T. (full throttle condition) in the following combination.
  • the mono-gap type spark plug B (negative polarity group) is adopted in which the center electrode 4 is in the negative side
  • a multi-gap type spark plug F (positive polarity group) is adopted in which the center electrode 4 is in the positive side.
  • the multi-gap type spark plug F has the metal shell 1, the insulator 2 and the center electrode 4 whose front end 41 extends from the front end 201 of the insulator 2.
  • three ground electrodes extend from the front end 11 of the metal shell 1.
  • Each of the front end surfaces 621 of the ground electrodes 62 has the noble metal tip 622 which faces an elevational side 411 of the front end 41 of the center electrode 4.
  • the noble metal tip 622 is made of Pt-based alloy containing 20 % Ir by weight, and measures 0.9 mm in diameter and 0.4 in thickness. In this instance, the noble metal tip may be provided around the front end 41 of the center electrode 4 through its entire circumferential length.
  • spark erosion resistance experimental test was carried out in the same manner as described in the first embodiment of the invention.
  • the result shows that no significant difference has found in the spark erosion rate between the multi-gap type spark plug F (positive polarity group) in which the center electrode is in the positive polarity side and the mono-gap type spark plug A (dual polarity group) in which the center electrode is in the positive polarity.
  • the multi-gap type spark plug D is adopted in which the center electrode 4 is in the negative side, and a multi-gap type spark plug E is used in which the center electrode 4 is in the positive side.
  • the multi-gap type spark plug E has the metal shell 1, the insulator 2 and the center electrode 4 whose front end 41 extends from the front end 201 of the insulator 2.
  • three ground electrodes extend from the front end 11 of the metal shell 1 to make their front end surface 621 face an elevational side 411 of the front end 41 of the center electrode 4.
  • spark erosion resistance experimental test was carried out in the same manner as described in the first embodiment of the invention.
  • the multi-polarity type spark plugs D, E were mounted on a 3000 cc, six-cylinder engine with the use of a dual polarity type device (DLI) in a dual polarity type ignition system to run the engine at 5500 rpm ⁇ W.O.T. (full throttle condition) in the following combination.
  • DLI dual polarity type device
  • the multi-gap type spark plug D negative polarity group
  • a multi-gap type spark plug F positive polarity group
  • the noble metal tips 622 are provided on the ground electrodes instead of the center electrode of the multi-gap type spark plug D.
  • the multi-gap type spark plug D has the metal shell 1, the insulator 2 and the center electrode 4 whose front end 41 extends from the front end 201 of the insulator 2.
  • the three ground electrodes 62 which extends from the front end 11 of the metal shell 1, have the front end surface 621 which faces the noble metal tip 51 provided on the elevational side 411 of the front end 41 of the center electrode 4.
  • the noble metal tip 622 is made of Pt-based alloy containing 20 % Ir by weight, and measures 0.9 mm in diameter and 0.4 in thickness.
  • spark erosion resistance experimental test was carried out in the same manner as described in the first embodiment of the invention.
  • the spark plugs D, F were mounted on a 3000 cc, V-type six-cylinder engine with the use of a dual polarity type device (DLI) in a dual polarity type ignition system to run the engine at 5500 rpm ⁇ W.O.T. (full throttle condition) in the following combination.
  • DLI dual polarity type device
  • the noble metal tip 622 used in the fifth embodiment of the invention may be made of Pt-Ni alloy metal as the same manner in the second embodiment of the invention. With this structure thus provided, it is possible to achieve the same effects as those mentioned in the fifth embodiment of the invention.
  • a mono-gap type spark plug G (negative polarity group) is adopted in which the center electrode 4 is in the negative side
  • the mono-gap type spark plug C (positive polarity group) is used in which the center electrode 4 is in the positive side.
  • the mono-gap type spark plug G is structurally the same as the spark plug of Figs. 1, 2 except that a noble metal tip 30 is provided only on the center electrode 4.
  • the noble metal tip 30 is made of Pt-based alloy containing 20 % Ir by weight, and measures 0.8 mm in diameter and 0.5 mm in thickness.
  • spark erosion resistance experimental test was carried out in the same manner as described in the first embodiment of the invention.
  • the spark plugs C, G were mounted on a 3000 cc, V-type six-cylinder engine with the use of a dual polarity type device (DLI) in a dual polarity type ignition system to run the engine at 5500 rpm ⁇ W.O.T. (full throttle condition) in the following combination.
  • DLI dual polarity type device
  • the combinatorial arrangement of the mono-gap type spark plug G and the mono-gap type spark plug C it is possible to reduce the amount of the noble metal compared to that required when the mono-gap type spark plug C (alternatively A) is uniformly used to each of the cylinders of the internal combustion engine. This makes it also possible to reduce the price of the product without losing a good spark erosion resistant property which is substantially insured when the mono-gap type spark plug C is uniformly used to each of the cylinders of the internal combustion engine.
  • Fig. 10 shows one example of the distributorless ignition device (DLI) in the dual polarity type ignition system for use in a V-type four-cylinder engine.
  • each of ignition coils 101 has a primary coil 111 whose one end is connected via a power source V1, and whose other end connected to an interruptor member 104 which includes a switching element 141 and a signal generator 142.
  • a main line 112 leads through a diode 113 to the spark discharge gap Gp of the spark plug which is arranged its polarity according to each of the aforementioned embodiments of the invention.
  • the spark discharge gap is represented by the single denotation Gp regardless of whether the spark plug is mono-gap type or multi-gap type one in Fig. 10.
  • the noble metal tip may be made of not only Pt-Ir aloy and Pt-Ni alloy but Pt-Ir-Ni alloy, Ir-Ni, alloy Pt-Pd and the like as well.
  • the dual polarity type DLI device can be used in which the number of the ignition coils is the same or half the number of the cylinders of the internal combustion engine.
  • the spark plugs used to a half side of the V-type engine has the same polarity to catelly unify the spark plugs used to half the number of the cylinder banks of the V-type engine so as to protect assemble workers from confusing.

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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)
EP19970302332 1996-04-05 1997-04-04 Zweifacher Polarität-Zündsystem für eine Zündkerzengruppe Expired - Lifetime EP0800247B1 (de)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP84270/96 1996-04-05
JP8427096 1996-04-05
JP8427096 1996-04-05
JP08692797A JP3924041B2 (ja) 1996-04-05 1997-04-04 両極性電源イグニッションシステム
JP86927/97 1997-04-04
JP8692797 1997-04-04

Publications (2)

Publication Number Publication Date
EP0800247A1 true EP0800247A1 (de) 1997-10-08
EP0800247B1 EP0800247B1 (de) 2001-09-19

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EP19970302332 Expired - Lifetime EP0800247B1 (de) 1996-04-05 1997-04-04 Zweifacher Polarität-Zündsystem für eine Zündkerzengruppe

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EP (1) EP0800247B1 (de)
JP (1) JP3924041B2 (de)
DE (1) DE69706739T2 (de)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1001502A2 (de) * 1998-11-09 2000-05-17 Ngk Spark Plug Co., Ltd Zündsystem
DE10148690B4 (de) * 2000-10-03 2014-02-27 Denso Corporation Zündvorrichtung

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4389385B2 (ja) 2000-02-18 2009-12-24 株式会社デンソー コージェネレーション用スパークプラグ及びその調整方法
DE10331267A1 (de) * 2003-07-10 2005-02-03 Robert Bosch Gmbh Brennstoffeinspritzsystem
FR2957491B1 (fr) * 2010-03-22 2013-07-12 Fiiish Leurre de peche

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07130454A (ja) * 1993-11-05 1995-05-19 Nippondenso Co Ltd スパ−クプラグ

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07130454A (ja) * 1993-11-05 1995-05-19 Nippondenso Co Ltd スパ−クプラグ
US5581145A (en) * 1993-11-05 1996-12-03 Nippondenso Co., Ltd. Spark plug

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 095, no. 008 29 September 1995 (1995-09-29) *

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1001502A2 (de) * 1998-11-09 2000-05-17 Ngk Spark Plug Co., Ltd Zündsystem
EP1001502A3 (de) * 1998-11-09 2001-12-12 Ngk Spark Plug Co., Ltd Zündsystem
US6617706B2 (en) 1998-11-09 2003-09-09 Ngk Spark Plug Co., Ltd. Ignition system
DE10148690B4 (de) * 2000-10-03 2014-02-27 Denso Corporation Zündvorrichtung

Also Published As

Publication number Publication date
JPH09326289A (ja) 1997-12-16
JP3924041B2 (ja) 2007-06-06
EP0800247B1 (de) 2001-09-19
DE69706739T2 (de) 2002-07-04
DE69706739D1 (de) 2001-10-25

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