EP1455086B1 - Glühkerze - Google Patents

Glühkerze Download PDF

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Publication number
EP1455086B1
EP1455086B1 EP04004740A EP04004740A EP1455086B1 EP 1455086 B1 EP1455086 B1 EP 1455086B1 EP 04004740 A EP04004740 A EP 04004740A EP 04004740 A EP04004740 A EP 04004740A EP 1455086 B1 EP1455086 B1 EP 1455086B1
Authority
EP
European Patent Office
Prior art keywords
coil portion
sheath
heating coil
glow plug
coating layer
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 - Fee Related
Application number
EP04004740A
Other languages
English (en)
French (fr)
Other versions
EP1455086A1 (de
Inventor
Chiaki Kumada
Shunsuke Gotoh
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 EP1455086A1 publication Critical patent/EP1455086A1/de
Application granted granted Critical
Publication of EP1455086B1 publication Critical patent/EP1455086B1/de
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23Q—IGNITION; EXTINGUISHING-DEVICES
    • F23Q7/00—Incandescent ignition; Igniters using electrically-produced heat, e.g. lighters for cigarettes; Electrically-heated glowing plugs
    • F23Q7/001—Glowing plugs for internal-combustion engines
    • 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

Definitions

  • the present invention relates to a glow plug used, for example, to preheat a diesel engine.
  • a glow plug 1 is composed substantially of a tubular metallic shell 2 and a sheathed heater 3, which extends axially through the metallic shell 2.
  • the sheathed heater 3 is configured as follows: while a resistance wire coil 3b-which consists of a heating coil portion 30b located on the side toward the distal end of the resistance wire coil 3b and a control coil portion 300b located on the side toward the rear end of the resistance wire coil 3b-and a distal end portion of a bar electrode 3c are placed in a sheath 3a made of a heat-resisting metal, whose distal end is closed in a substantially hemispherical shape and whose rear end is open, the sheath 3a is filled with an insulating MgO (magnesium oxide) powder 3d, and an insulating rubber packing 3e is interposed between the bar electrode 3c and the inner surface of an opening portion of the sheath 3a to thereby seal the opening.
  • MgO manganesium oxide
  • the bar electrode 3c is disposed such that its distal end is located in a longitudinally intermediate portion of the interior of the sheath 3a and electrically connected to the resistance wire coil 3b (control coil portion 300b), whereas its rear end extends along the axis of the metallic shell 2 and projects outward therefrom.
  • the resistance wire coil 3b (heating coil portion 30b) is electrically connected to the inner surface of the closed distal end of the sheath 3a. Accordingly, the bar electrode 3c and the sheath 3a are electrically connected together via the resistance wire coil 3b.
  • the resistance wire coil 3b of the self-control-type glow plug 1 is configured such that the heating coil portion 30b and the control coil portion 300b are connected in series. Mainly the heating coil portion 30b generates heat to cause the distal end of the sheath 3a to glow, whereas the control coil portion 300b rapidly increases in electric resistance with temperature to suppress current flowing to the heating coil portion 30b. As has just been described, in the resistance wire coil 3b, the heating coil portion 30b and the control coil portion 300b have respective roles. Material is selected as appropriate in accordance with the roles.
  • an Fe-Cr alloy or an Ni-Cr alloy, each of which exhibits excellent resistance to oxidation and heat, is used to form the heating coil portion 30b; and in order that its electric resistance sensitively reflects a change in temperature, pure Fe or the like, which has a high positive temperature-resistance coefficient, is used to form the control coil portion 300b (refer to, for example, Patent Document 1).
  • pure Fe is employed as material for the control coil portion 300b, and, in order to enhance oxidation resistance of the pure Fe, the surface of an Fe wire is plated with Ni or Cr.
  • the heating coil portion 30b material having excellent resistance to heat and oxidation is selected as material for the heating coil portion 30b.
  • the heating coil portion 30b formed of such material fails to exhibit expected durability.
  • the heating coil portion 30b in the case where the heating coil portion 30b is formed of an Fe-Cr-Al alloy, the heating coil portion 30b must sufficiently endure the temperature of 1,000°C in the light of resistance to heat and oxidation of the alloy.
  • the heating coil portion 30b was actually manufactured from the alloy and subjected to a durability test at 1,000°C (a test method will be described later), the test confirmed a phenomenon that the surface of the heating coil portion 30b melted with resultant breakage of the heating coil portion 3b.
  • An object of the present invention is to provide a glow plug that exhibits excellent durability at high temperature, particularly a high temperature in excess of 1,000°C.
  • the present invention provides a glow plug comprising a sheathed heater and a tubular metallic shell, the sheathed heater comprising a tubular sheath having a closed distal end, a resistance wire coil disposed in the sheath and having at least a heating coil portion, an insulating MgO powder charged in the sheath, and a bar electrode having one end inserted into a rear end of the sheath in a sealed condition, the sheathed heater being inserted into a tubular hole of the metallic shell with a distal end portion of the sheath projecting outward from the metallic shell, wherein the heating coil portion comprises a coil base material and a coating layer, which covers the surface of the coil base material, and the coating layer is formed of Pt, Pd, Rh, or an alloy of two or more of Pt, Pd, and Rh, and wherein the
  • the coil base material of the heating coil portion is coated with a coating layer formed of Pt, Pd, Rh, or an alloy of two or more of Pt, Pd, and Rh so as to prevent direct contact between MgO and the coil base material, thereby yielding a glow plug that exhibits practically sufficient durability even at a high temperature in excess of 1,000°C.
  • FIG. 1 is a vertical sectional view of a glow plug including a partially enlarged view.
  • a glow plug 1 is composed substantially of a tubular metallic shell 2 and a sheathed heater 3, which extends axially through the metallic shell 2.
  • the sheathed heater 3 is configured as follows: while a resistance wire coil 3b-which consists of a heating coil portion 30b located on the side toward the distal end of the resistance wire coil 3b and a control coil portion 300b located on the side toward the rear end of the resistance wire coil 3b-and a distal end portion of a bar electrode 3c are placed in a sheath 3a made of a heat-resisting metal, whose distal end is closed in a substantially hemispherical shape and whose rear end is open, the sheath 3a is filled with an insulating MgO powder 3d, and an insulating rubber packing 3e is interposed between the bar electrode 3c and the inner surface of an opening portion of the sheath 3a to thereby seal the opening.
  • the bar electrode 3c is disposed such that its distal end is located in a longitudinally intermediate portion of the interior of the sheath 3a and electrically connected to the resistance wire coil 3b, whereas its rear end extends along the axis of the metallic shell 2 and projects outward therefrom.
  • the resistance wire coil 3b is electrically connected to the inner surface of the closed distal end of the sheath 3a. Accordingly, the bar electrode 3c and the sheath 3a are electrically connected together via the resistance wire coil 3b.
  • the resistance wire coil 3b is configured such that the heating coil portion 30b and the control coil portion 300b are connected in series. Mainly the heating coil portion 30b generates heat to cause the distal end of the sheath 3a to glow, whereas the control coil portion 300b plays the role of suppressing current flowing to the heating coil portion 30b by virtue of its property that electric resistance increases rapidly with temperature. In order that its electric resistance sensitively reflects a change in temperature, a material having a high positive temperature-resistance coefficient, such as pure Fe or a Co-Ni alloy, is used to form the control coil portion 300b.
  • the heating coil portion 30b is configured as follows: an Fe-Cr-Al alloy or an Ni-Cr alloy, which has excellent resistance to oxidation and heat, is used as a coil base material 31b; and the surface of the coil base material 31b is coated with a coating layer 32b.
  • the coating layer 32b is formed to be thin (preferred range of thickness: 0.2 to 0.5 ⁇ m, thickness in this embodiment: 0.3 ⁇ m) and uniform, from Pt (platinum), Pd (palladium), Rh (rhodium), or an alloy of two or more of Pt, Pd, and Rh through, for example, plating or vapor deposition.
  • the coating layer 32b Since these metals used to form the coating layer 32b have high ductility and malleability, the coating layer 32b is unlikely to crack even when the resistance wire coil 3b undergoes a reduction in diameter in the process of swaging the sheath 3a. Incidentally, when the coating layer 32b cracks, the coil base material 31b and the insulating MgO powder 3d come into contact with each other through the crack, resulting in impaired durability at high temperature.
  • the glow plugs 1 as shown in FIG. 1 were manufactured and subjected to a durability test.
  • the test results are shown in Table 1.
  • the glow plugs 1 were continuously subjected to test cycles, each cycle consisting of application of 11 Vdc for 10 sec ⁇ application of 13 Vdc for 300 sec ⁇ OFF for 60 sec.
  • the maximum temperature of the heating coil portion 30b reaches about 1,100°C.
  • the “Durability” column shows overall evaluation based on the results of "Breakage of wire " and "Performance deterioration.”
  • "x” denotes that a problem exists in terms of durability
  • "o” denotes that no problem exists in terms of durability.
  • glow plugs Nos. 3 to 5 which correspond to embodiments of the present invention, exhibit excellent durability as compared with glow plugs Nos. 1 and 2.
  • performance deterioration is brought about conceivably as a result of alloying of Ni and the coil base material 31b.
  • the present invention has been described with reference to an embodiment, the present invention is not limited thereto.
  • the embodiment is described while mentioning the self-control-type glow plug 1; however, the present invention is also applicable to a glow plug that does not include the control coil portion 300b; i.e., to a glow plug in which the entire resistance wire coil 3b serves as the heating coil portion 30b.
  • the gist of the present invention resides in the structure of the heating coil portion 30b. Therefore, no particular limitation is imposed on the structure of the control coil portion 300b.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Resistance Heating (AREA)

Claims (3)

  1. Eine Glühkerze, enthaltend einen umhüllten Heizer und eine röhrenförmige metallische Ummantelung, wobei der umhüllte Heizer eine röhrenförmige Hülle mit einem geschlossenen Distalende, eine resistive Leitungsspule, die in der Hülle angeordnet ist und die zumindest einen Heizungsspulenabschnitt aufweist, ein isolierendes MgO-Pulver, das in die Hülle gefüllt ist, und eine Stabelektrode mit einem Ende aufweist, das in ein hinteres Ende der Hülle in einem versiegelten Zustand eingesetzt ist, und wobei der umhüllte Heizer in ein röhrenförmiges Loch der metallischen Ummantelung eingesetzt ist, wobei ein Distalende-Abschnitt der Hülle nach außen ragt,
    wobei der Heizungsspulenabschnitt ein Spulen-Basismaterial und und eine Beschichtungsschicht enthält, die die Oberfläche des Spulen-Basismaterials bedeckt, und wobei die Beschichtungsschicht aus Pt, Pd, Rh oder aus einer Legierung von zwei oder mehr Elementen aus Pt, Pd und Rh gebildet ist, und wobei
    das Spulen-Basismaterial des Heizungsspulenabschnitts eine Fe-Cr-Al-Legierung ist.
  2. Eine Glühkerze gemäß Anspruch 1, wobei die Beschichtungsschicht eine Dicke von 0,2 µm bis 0,5 µm hat.
  3. Eine Glühkerze gemäß einem der Ansprüche 1 oder 2, wobei die Beschichtungsschicht Pt enthält.
EP04004740A 2003-03-03 2004-03-01 Glühkerze Expired - Fee Related EP1455086B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003055392A JP2004263951A (ja) 2003-03-03 2003-03-03 グロープラグ
JP2003055392 2003-03-03

Publications (2)

Publication Number Publication Date
EP1455086A1 EP1455086A1 (de) 2004-09-08
EP1455086B1 true EP1455086B1 (de) 2006-09-20

Family

ID=32821142

Family Applications (1)

Application Number Title Priority Date Filing Date
EP04004740A Expired - Fee Related EP1455086B1 (de) 2003-03-03 2004-03-01 Glühkerze

Country Status (4)

Country Link
US (1) US20040173595A1 (de)
EP (1) EP1455086B1 (de)
JP (1) JP2004263951A (de)
DE (1) DE602004002416T2 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8319153B2 (en) * 2008-11-17 2012-11-27 Federal-Mogul Italy Srl. Glow plug with metallic heater probe
JP5922946B2 (ja) * 2012-02-22 2016-05-24 日本特殊陶業株式会社 グロープラグ
EP2840314B1 (de) * 2012-04-16 2020-01-15 NGK Sparkplug Co., Ltd. Glühkerze
JP6689022B2 (ja) * 2014-04-09 2020-04-28 日本特殊陶業株式会社 グロープラグ

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4582980A (en) * 1984-03-09 1986-04-15 Fabbrica Italiana Magneti Marelli S.P.A. Glow plug for diesel engines of motor vehicles
US6121577A (en) * 1997-12-20 2000-09-19 Daimlerchrysler Ag Electrically heatable glow plug with oxygen getter material

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2900984C2 (de) * 1979-01-12 1983-01-05 W.C. Heraeus Gmbh, 6450 Hanau Glühkerze für Dieselmotoren
JPS55125363A (en) * 1979-03-20 1980-09-27 Toyota Central Res & Dev Lab Inc Self-heating ignitor
US5084606A (en) * 1990-05-17 1992-01-28 Caterpillar Inc. Encapsulated heating filament for glow plug
JP2001153359A (ja) * 1999-11-26 2001-06-08 Ngk Spark Plug Co Ltd グロープラグ
US6465759B1 (en) * 2000-03-14 2002-10-15 Delphi Technologies, Inc. Ion sensor glow plug assembly
US6512204B1 (en) * 2000-03-14 2003-01-28 Delphi Technologies, Inc. Ion sensor glow plug assembly

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4582980A (en) * 1984-03-09 1986-04-15 Fabbrica Italiana Magneti Marelli S.P.A. Glow plug for diesel engines of motor vehicles
US6121577A (en) * 1997-12-20 2000-09-19 Daimlerchrysler Ag Electrically heatable glow plug with oxygen getter material

Also Published As

Publication number Publication date
US20040173595A1 (en) 2004-09-09
DE602004002416D1 (de) 2006-11-02
EP1455086A1 (de) 2004-09-08
DE602004002416T2 (de) 2007-09-20
JP2004263951A (ja) 2004-09-24

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