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WO2010043544A1 - Sparkplug with integrated coil - Google Patents

Sparkplug with integrated coil Download PDF

Info

Publication number
WO2010043544A1
WO2010043544A1 PCT/EP2009/063119 EP2009063119W WO2010043544A1 WO 2010043544 A1 WO2010043544 A1 WO 2010043544A1 EP 2009063119 W EP2009063119 W EP 2009063119W WO 2010043544 A1 WO2010043544 A1 WO 2010043544A1
Authority
WO
WIPO (PCT)
Prior art keywords
shaft
coil
electrode
sparkplug
spark plug
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.)
Ceased
Application number
PCT/EP2009/063119
Other languages
French (fr)
Inventor
Volker Heise
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.)
Delphi Technologies Inc
Original Assignee
Delphi Technologies Inc
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 Delphi Technologies Inc filed Critical Delphi Technologies Inc
Priority to EP09783863A priority Critical patent/EP2351173B1/en
Publication of WO2010043544A1 publication Critical patent/WO2010043544A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • 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
    • H01T13/40—Sparking plugs structurally combined with other devices
    • H01T13/44—Sparking plugs structurally combined with other devices with transformers, e.g. for high-frequency ignition

Definitions

  • the present invention relates generally to a sparkplug for an internal combustion engine.
  • the traditional ignition system consists of a sparkplug acting as an electrical feed into a combustion chamber of a gasoline engine, providing concentrated thermal energy release, in the form of a spark, to initiate the combustion.
  • a conventional transformer is used, incorporating electronics to condition and to feed energy from the electrical network in vehicles (Battery, Generator).
  • a resonance based ignition system comprises of a resonator (2), a generator (1) and heat release interface (3).
  • a resonance ignition system requires an electrical feed through into the combustion chamber as conventional systems.
  • Conventional ignition systems do have at least two separate elements aside of the variety of harnesses topologies: Sparkplug, Ignition-coil
  • the shaft of the sparkplug is designed to withstand the voltages applied to the centre electrode of this removable interface: Sparkplug to Ignition- coil or Sparkplug to harness-terminal. The purpose is to not let the spark finding its path to ground outside the combustion chamber.
  • Such interface is adding mechanical length, which is adding electrical capacitance to the output or load of and ignition system.
  • the present invention provides integration of the electrical feed-through with the resonance coil, while combining both into one element.
  • the result is that there is no removable interface between the spark-plug and the ignition resonance coil.
  • the benefit is a reduced capacitance of the electrical feed through side, which allows a higher amplification of the resonance structure. Furthermore it reduces the variability of resonance frequency compared to a separate design of two elements, because the resonance frequency is a function of the electrical features of both elements.
  • a spark plug for an internal combustion engine comprising a lower centre electrode and a ground electrode facing the combustion side of the engine, said ground electrode extending from an electrically conductive annular body connected to the ground, and comprising a hollow shaft made of insulating material, said shaft comprising a lower portion extending between the centre electrode and the body, characterized in that said shaft comprises an upper portion around which an ignition coil is wound.
  • the shaft is made out of ceramic material and is cylindrical and hollow in geometry;
  • the upper end of the centre electrode is accessible through an open side of the shaft and designed/finished in form of a terminal suitable to connect the starting wire of the coil at the lower end of the coil;
  • the coil is made of a single layer coil;
  • FIG. 1 is a bloc-diagram showing a resonance based ignition system
  • FIG. 2 is a perspective view showing a conventional sparkplug
  • FIG. 3 is a cross sectional view showing a sparkplug according to the present invention.
  • a conventional spark plug- centre electrode 10 is made out of three major elements, which are the lower electrode 12 facing the combustion side, conductive cement 14 forming a current limiting resistor and an upper electrode 16 pointing towards the ignition-coil interface 18.
  • the conductive cement 14 and the upper electrode 16 are built in the shaft 20 of the spark-plug 22 which is made of insulating material such as ceramic material.
  • the centre electrode 10 and the shaft 20 are arranged in a generally cylindrical tubular metal body 24 which acts as the ground for the sparks passing through the center electrode 10 to a ground electrode 26 extending from the lower tip of the body 24.
  • the body 24 comprises a threaded outer portion 28 to be threadedly engaged in the cylinder head of the engine.
  • the ground electrode 26 can be made from high nickel steel and is welded to the side of the body lower end 30. Multiple side electrodes may also be used, so that they do not overlap the centre electrode 10.
  • the spark-plug 22 is designed such that a single layer coil 32 can be wound on the shaft 20 like in figure 3.
  • the possible implementation would extend the shaft 20.
  • the lower end 34 (engine face) of the spark-plug 22 would remain unchanged compared to conventional spark-plug.
  • the shaft 20 is made out of the existing ceramic material and is cylindrical and hollow in geometry, forming a central bore 38 such that the centre electrode upper end 36 at the lower end of the central bore 38 is accessible through the open side 40 of the shaft end and designed/finished in form of a terminal 42 suitable to connect the starting wire 44 of the coil 32.
  • the single layer coil wire 46 of diameter 0.5mm ⁇ d ⁇ 2mm is contacted through a hole 48 at the low bottom side of the ceramic directly on the lower electrode surface or in case the electrode 10 requires an additional anchor, the anchor provides suitable terminal 42.
  • the open side 40 of the shaft 20 allows inserting suitable means to contact this wire end on the terminal 42 inside the hollow shaft 20 with any suitable brazing and soldering method. Thereafter the wire 46 is wound on the shaft 20.
  • the wire 46 requires defined guidance for winding on either the shaft 20 itself, or through an additional sleeve 50 on the shaft 20. Both options require suitable grooves 52 in form of a screw to guide the wire 46 and to define the distance from turn to turn.
  • Such construction requires further an insulation layer 54 and a nonmagnetic metal layered shield 56 on top of the single layer coil 32.
  • the hollow shaft 20 comprises a lower portion 58 standing between the centre electrode 10 and the annular body 24, and an upper portion 60 forming the core member of the ignition coil 32, said ignition coil 32 being wound around said upper portion 60.
  • the lower portion 58 and the upper portion 60 of the shaft 20 are made of one piece.
  • the centre electrode 10 extends essentially from the lower end 62 to the upper end 64 of the hollow shaft lower portion 58.
  • the centre electrode 10 is inserted coaxially in the through bore portion extending axially in the shaft lower portion 58.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Spark Plugs (AREA)

Abstract

Sparkplug for an internal combustion engine comprising a lower electrode (1) facing the combustion side of the engine and a shaft (4), characterized in that an ignition coil (13) is wound on the shaft (4) of the sparkplug. The shaft (4) is made out of ceramic material and is cylindrical and hollow in geometry, such that the centre electrode end at the lower end is accessible through the open side of the shaft end and designed/finished in form of a terminal (6) suitable to connect the starting wire of the coil.

Description

Sparkplug with integrated coil
TECHNICAL FIELD
The present invention relates generally to a sparkplug for an internal combustion engine.
BACKGROUND OF THE INVENTION The traditional ignition system consists of a sparkplug acting as an electrical feed into a combustion chamber of a gasoline engine, providing concentrated thermal energy release, in the form of a spark, to initiate the combustion. A conventional transformer is used, incorporating electronics to condition and to feed energy from the electrical network in vehicles (Battery, Generator).
Future direct injection combustion systems are targeting stratified fuel injection, promising significant fuel reduction at low speed and partial load. These stratified gasoline mixtures tend to be difficult to ignite with existing ignition systems, mostly because of the limited energy and the very local distribution of the released heat of the spark itself.
Alternatives are intelligently controlled resonance structures which allow emitting heat over larger space, constant over time, and at extended time compared to existing ignition systems. These systems require at minimum, the resonance structure, and a driving generator. As shown on figure 1 , a resonance based ignition system comprises of a resonator (2), a generator (1) and heat release interface (3).
If one part of the resonator is realized by conventional high frequency coils, then a resonance ignition system requires an electrical feed through into the combustion chamber as conventional systems. Conventional ignition systems do have at least two separate elements aside of the variety of harnesses topologies: Sparkplug, Ignition-coil
Whereas the shaft of the sparkplug is designed to withstand the voltages applied to the centre electrode of this removable interface: Sparkplug to Ignition- coil or Sparkplug to harness-terminal. The purpose is to not let the spark finding its path to ground outside the combustion chamber. Such interface is adding mechanical length, which is adding electrical capacitance to the output or load of and ignition system.
In such resonance based ignition system this additional capacitance is limiting the voltage (amplification) increase of the resonance structure. It has been proposed in document EP 1758219 to design a sparkplug with a serially connected resonator comprising a center electrode which is attached directly to the lower end of the resonator, the coil being connected directly to the upper end of the center electrode. However, this spark plug is not entirely satisfactory as for ignition efficiency and it requires some specific assembly steps which are not easy to implement.
It is an objective of the present invention to solve the above mentioned problems in a simple and economic way.
SUMMARY OF THE INVENTION In order to solve the above mentioned problems, the present invention provides integration of the electrical feed-through with the resonance coil, while combining both into one element.
The result is that there is no removable interface between the spark-plug and the ignition resonance coil. The benefit is a reduced capacitance of the electrical feed through side, which allows a higher amplification of the resonance structure. Furthermore it reduces the variability of resonance frequency compared to a separate design of two elements, because the resonance frequency is a function of the electrical features of both elements.
According to the present invention, it is proposed a spark plug for an internal combustion engine comprising a lower centre electrode and a ground electrode facing the combustion side of the engine, said ground electrode extending from an electrically conductive annular body connected to the ground, and comprising a hollow shaft made of insulating material, said shaft comprising a lower portion extending between the centre electrode and the body, characterized in that said shaft comprises an upper portion around which an ignition coil is wound.
According to other features of the present invention:
- the shaft is made out of ceramic material and is cylindrical and hollow in geometry;
- the upper end of the centre electrode is accessible through an open side of the shaft and designed/finished in form of a terminal suitable to connect the starting wire of the coil at the lower end of the coil; - the coil is made of a single layer coil;
- it further comprises a nonmagnetic metal layered shield on top of the coil.
BRIEF DESCRIPTION OF THE DRAWINGS The present invention is now described by way of example with reference to the accompanying drawings in which:
- figure 1 is a bloc-diagram showing a resonance based ignition system;
- figure 2 is a perspective view showing a conventional sparkplug;
- figure 3 is a cross sectional view showing a sparkplug according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown on figure 2, a conventional spark plug- centre electrode 10 is made out of three major elements, which are the lower electrode 12 facing the combustion side, conductive cement 14 forming a current limiting resistor and an upper electrode 16 pointing towards the ignition-coil interface 18. The conductive cement 14 and the upper electrode 16 are built in the shaft 20 of the spark-plug 22 which is made of insulating material such as ceramic material.
The centre electrode 10 and the shaft 20 are arranged in a generally cylindrical tubular metal body 24 which acts as the ground for the sparks passing through the center electrode 10 to a ground electrode 26 extending from the lower tip of the body 24. The body 24 comprises a threaded outer portion 28 to be threadedly engaged in the cylinder head of the engine.
The ground electrode 26 can be made from high nickel steel and is welded to the side of the body lower end 30. Multiple side electrodes may also be used, so that they do not overlap the centre electrode 10.
According to the present invention, the spark-plug 22 is designed such that a single layer coil 32 can be wound on the shaft 20 like in figure 3. The possible implementation would extend the shaft 20. The lower end 34 (engine face) of the spark-plug 22 would remain unchanged compared to conventional spark-plug.
The shaft 20 is made out of the existing ceramic material and is cylindrical and hollow in geometry, forming a central bore 38 such that the centre electrode upper end 36 at the lower end of the central bore 38 is accessible through the open side 40 of the shaft end and designed/finished in form of a terminal 42 suitable to connect the starting wire 44 of the coil 32. This means that the conventional cement and upper centre electrode are removed. The single layer coil wire 46 of diameter 0.5mm<d<2mm is contacted through a hole 48 at the low bottom side of the ceramic directly on the lower electrode surface or in case the electrode 10 requires an additional anchor, the anchor provides suitable terminal 42. The open side 40 of the shaft 20 allows inserting suitable means to contact this wire end on the terminal 42 inside the hollow shaft 20 with any suitable brazing and soldering method. Thereafter the wire 46 is wound on the shaft 20.
The wire 46 requires defined guidance for winding on either the shaft 20 itself, or through an additional sleeve 50 on the shaft 20. Both options require suitable grooves 52 in form of a screw to guide the wire 46 and to define the distance from turn to turn.
Such construction requires further an insulation layer 54 and a nonmagnetic metal layered shield 56 on top of the single layer coil 32.
The hollow shaft 20 comprises a lower portion 58 standing between the centre electrode 10 and the annular body 24, and an upper portion 60 forming the core member of the ignition coil 32, said ignition coil 32 being wound around said upper portion 60. The lower portion 58 and the upper portion 60 of the shaft 20 are made of one piece.
The centre electrode 10 extends essentially from the lower end 62 to the upper end 64 of the hollow shaft lower portion 58. The centre electrode 10 is inserted coaxially in the through bore portion extending axially in the shaft lower portion 58.

Claims

1. Spark plug (22) for an internal combustion engine comprising a lower centre electrode (10) and a ground electrode (26) facing the combustion side of the engine, said ground electrode (26) extending from an electrically conductive annular body (20) connected to the ground, and comprising a hollow shaft (20) made of insulating material, said shaft (20) comprising a lower portion (58) extending between the centre electrode (10) and the body (20), characterized in that said shaft (20) comprises an upper portion (60) around which an ignition coil (32) is wound.
2. Spark plug (22) according to claim 1, characterized in that the shaft (20) is made out of ceramic material and is cylindrical and hollow in geometry.
3. Spark plug (22) according to any of the preceding claims, characterized in that the upper end (36) of the centre electrode (10) is accessible through an open side (40) of the shaft (20) and designed/finished in form of a terminal (42) suitable to connect the starting wire (44) of the coil (32) at the lower end of the coil (32).
4. Spark plug (22) according to any of the preceding claims, characterized in that the coil (32) is made of a single layer coil.
5. Spark plug (22) according to any of the preceding claims, characterized in that it further comprises a nonmagnetic metal layered shield (56) on top of the coil (32).
PCT/EP2009/063119 2008-10-13 2009-10-08 Sparkplug with integrated coil Ceased WO2010043544A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP09783863A EP2351173B1 (en) 2008-10-13 2009-10-08 Sparkplug with integrated coil

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP08166510.1 2008-10-13
EP08166510 2008-10-13

Publications (1)

Publication Number Publication Date
WO2010043544A1 true WO2010043544A1 (en) 2010-04-22

Family

ID=40512229

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2009/063119 Ceased WO2010043544A1 (en) 2008-10-13 2009-10-08 Sparkplug with integrated coil

Country Status (2)

Country Link
EP (1) EP2351173B1 (en)
WO (1) WO2010043544A1 (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2456027A1 (en) * 2010-11-23 2012-05-23 Delphi Technologies, Inc. Encapsulation of a high frequency resonator for the ignition system of an internal combustion engine
FR2982711A1 (en) * 2011-11-16 2013-05-17 Renault Sa Spark plug for use on combustion chamber of internal combustion engine of vehicle, has insulator extending longitudinally from stopper to vicinity of free end of electrode, and coil fixed on external part of internal hollow wall
JP2014505338A (en) * 2010-12-15 2014-02-27 フェデラル−モーグル・イグニション・カンパニー Corona igniter with improved insulation, including ignition coil
USD1089097S1 (en) 2021-06-23 2025-08-19 Caterpillar Inc. Spark plug

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467534A (en) * 1946-11-09 1949-04-19 American Bosch Corp Ignition unit
US20040025854A1 (en) 2002-08-08 2004-02-12 Tetsuya Miwa Ignition device for an internal combustion engine
EP1758219A1 (en) 2005-08-25 2007-02-28 Renault SAS Spark plug for internal combustion engine

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2467534A (en) * 1946-11-09 1949-04-19 American Bosch Corp Ignition unit
US20040025854A1 (en) 2002-08-08 2004-02-12 Tetsuya Miwa Ignition device for an internal combustion engine
EP1758219A1 (en) 2005-08-25 2007-02-28 Renault SAS Spark plug for internal combustion engine

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2456027A1 (en) * 2010-11-23 2012-05-23 Delphi Technologies, Inc. Encapsulation of a high frequency resonator for the ignition system of an internal combustion engine
JP2014505338A (en) * 2010-12-15 2014-02-27 フェデラル−モーグル・イグニション・カンパニー Corona igniter with improved insulation, including ignition coil
FR2982711A1 (en) * 2011-11-16 2013-05-17 Renault Sa Spark plug for use on combustion chamber of internal combustion engine of vehicle, has insulator extending longitudinally from stopper to vicinity of free end of electrode, and coil fixed on external part of internal hollow wall
USD1089097S1 (en) 2021-06-23 2025-08-19 Caterpillar Inc. Spark plug

Also Published As

Publication number Publication date
EP2351173B1 (en) 2012-11-07
EP2351173A1 (en) 2011-08-03

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