EP2020714A2 - Dispositif d'allumage multi-points - Google Patents

Dispositif d'allumage multi-points Download PDF

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Publication number
EP2020714A2
EP2020714A2 EP07021927A EP07021927A EP2020714A2 EP 2020714 A2 EP2020714 A2 EP 2020714A2 EP 07021927 A EP07021927 A EP 07021927A EP 07021927 A EP07021927 A EP 07021927A EP 2020714 A2 EP2020714 A2 EP 2020714A2
Authority
EP
European Patent Office
Prior art keywords
combustion chamber
ignition
electrode pairs
extinguishing action
side wall
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
EP07021927A
Other languages
German (de)
English (en)
Other versions
EP2020714B1 (fr
EP2020714A3 (fr
Inventor
Katsuaki Minami
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.)
Miyama Inc
Original Assignee
Miyama 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
Priority claimed from JP2007200420A external-priority patent/JP4079989B1/ja
Priority claimed from JP2007203846A external-priority patent/JP4139849B1/ja
Application filed by Miyama Inc filed Critical Miyama Inc
Publication of EP2020714A2 publication Critical patent/EP2020714A2/fr
Publication of EP2020714A3 publication Critical patent/EP2020714A3/fr
Application granted granted Critical
Publication of EP2020714B1 publication Critical patent/EP2020714B1/fr
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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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
    • H01T13/46—Sparking plugs having two or more spark gaps
    • H01T13/462—Sparking plugs having two or more spark gaps in series connection

Definitions

  • This invention relates to a multipoint ignition device in which a plurality of ignition gaps are disposed in a single combustion chamber.
  • JP2-123281A and JP1-193080A disclose a multipoint ignition device in which a plurality of electrode pairs constituting ignition gaps are disposed around a cylinder opening portion such that an air-fuel mixture in a combustion chamber is ignited from the plurality of ignition gaps.
  • the flames that grow from the respective ignition gaps ideally have a uniform propagation speed.
  • the propagation speed of the flame that grows from each ignition gap receives a cooling effect (extinguishing action) from the wall surface of the combustion chamber.
  • the extinguishing action varies according to the position on the wall surface of the combustion chamber such that when the extinguishing action is large, the amount of energy used to propagate the flame decreases, leading to a lower propagation speed, and when the extinguishing action is small, the propagation speed of the flame rises.
  • unevenness occurs in the propagation speed of the flame.
  • This invention has been designed in consideration of this technical problem, and it is an object thereof to make the propagation speeds of flames that grow from respective ignition gaps in a multipoint ignition device uniform.
  • a multipoint ignition device In a multipoint ignition device according to this invention, a plurality of electrode pairs are caused to project from a side wall of a combustion chamber of an engine, and the propagation speed of a flame that grows from each ignition gap is made uniform by varying the distance between the ignition gap and the side wall of the combustion chamber according to the respective positions of the plurality of electrode pairs.
  • a post-ignition flame can propagate through an entire combustion chamber quickly, enabling a reduction in the amount of time required to burn an air-fuel mixture in the combustion chamber.
  • FIG. 1 is a schematic constitutional diagram of an engine comprising a multipoint ignition device according to this invention.
  • FIG. 2 is a schematic constitutional diagram of the multipoint ignition device.
  • FIGs. 3 and 4 are enlarged views of an electrode pair.
  • FIG. 5 is a schematic constitutional diagram of a multipoint ignition device having a different constitution.
  • FIG. 1 shows the schematic constitution of an engine 1 comprising a multipoint ignition device 7 according to this invention.
  • the engine 1 is a four-valve engine having two intake valves 3 and two exhaust valves 4 for a single combustion chamber 2.
  • the combustion chamber 2 is a so-called pent roof (triangular roof) type in which a squish area S, where the height of the combustion chamber 2 is lower than the height of the other parts, is formed in intake side and exhaust side corner portions of the combustion chamber 2.
  • the multipoint ignition device 7 is formed integrally with a head gasket 8 of the engine 1.
  • a plurality of electrode pairs P1 to P8 constituting ignition gaps G1 to G8 are disposed at substantially equal intervals around a cylinder opening portion 14 that opens onto an upper surface of the cylinder block 10.
  • Each electrode pair P1 to P8 is constituted by a current-carrying electrode and an earth electrode that faces the current-carrying electrode via a minute gap.
  • each electrode pair P1 to P8 is formed from a metal exhibiting high heat resistance, such as nickel or platinum.
  • a plurality of openings are formed in the head gasket 8, and a central opening 13, which is the largest opening, has a substantially identical diameter to the cylinder opening portion 14 and is superposed on the cylinder opening portion 14.
  • An inner peripheral surface of the opening 13 constitutes a side wall of the combustion chamber 2.
  • a plurality of openings 15 disposed around the opening 13 serve as water holes connected to cooling water passages formed in the cylinder head 9 and cylinder block 10.
  • An intermediate member 16 formed from a conductive material is connected to each of the electrode pairs P1 to P8 such that adjacent electrode pairs are connected by the intermediate member 16.
  • the intermediate members 16 are formed from the same material as the electrode pairs P1 to P8, for example nickel, but may be formed from a different material such as copper.
  • the intermediate members 16 are buried in and held by the head gasket 8, and thus the electrode pairs P1 to P8 are held on the head gasket 8.
  • the intermediate members 16 function to connect the electrode pairs P1 to P8 electrically in series.
  • discharge occurs first in the ignition gap G1 of the electrode pair P1 connected to the terminal 20, after which discharge occurs in the ignition gap G2 of the electrode pair P2 adjacent thereto.
  • Discharge then occurs in the manner of a chain reaction in sequence from the terminal 20 side until finally, discharge occurs in the ignition gap G8 of the electrode pair P8 connected to an earth terminal 19.
  • a distance L between the ignition gaps G1 to G8 of the electrode pairs P1 to P8 and the side wall of the combustion chamber 2, or in other words the inner peripheral surface of the opening 13 in the head gasket 8, differs according to the position of the electrode pair P1 to P8 such that the propagation speed of flames that grow from the respective ignition gaps G1 to G8 is uniform. More specifically, a projection amount h (see FIG.
  • the reason for this is that near the ridge line X of the pent roof, the height of the combustion chamber 2 is greater than the height of the other parts, and therefore the contact area between the flame and the wall surface of the combustion chamber 2 is large such that the extinguishing action produced by the wall surface of the combustion chamber 2 is greater than that of the other parts.
  • the extinguishing action produced by the wall surface of the combustion chamber 2 is less likely to be received, and the propagation speed of the flames that grow from the ignition gaps G2, G6 can be prevented from falling below the propagation speed of the flames that grow from the other ignition gaps due to the extinguishing action.
  • the height of the combustion chamber 2 in the squish areas S is lower than the height of the other parts, and therefore the contact area between the flame and the wall surface of the combustion chamber 2 is small such that the extinguishing action produced by the wall surface of the combustion chamber 2 is smaller than that of the other parts.
  • the extinguishing action produced by the wall surface of the combustion chamber 2 is more likely to be received, and the propagation speed of the flames that grow from the ignition gaps G4, G8 can be prevented from becoming faster than the propagation speed of the flames that grow from the other ignition gaps.
  • the projection amount h of the electrode pairs P3 to P5 disposed on the exhaust side of the combustion chamber 2 may also be reduced.
  • the reason for this is that on the exhaust side of the combustion chamber 2, the wall surface temperature is higher than on the intake side due to the high-temperature exhaust gas, the exhaust valves 4, and the heat received from the valve seats thereof, and therefore the extinguishing action produced by the wall surface of the combustion chamber 2 is correspondingly smaller.
  • the distance 1 between the ignition gaps G1 to G8 of the electrode pairs P1 to P8 and the side wall of the combustion chamber 2 is varied according to the position of the electrode pair P1 to P8 so that the propagation speed of the flames that grow from the ignition gaps G1 to G8 can be made uniform, and as a result, the flames can propagate through the entire combustion chamber 2 quickly, enabling a reduction in the amount of time required to burn the air-fuel mixture in the combustion chamber 2.
  • the distance L between the ignition gaps G1 to G8 and the side wall of the combustion chamber 2 is varied according to the position of the electrode pair P1 to P8 by varying the projection amount h of the electrode pairs P1 to P8.
  • bowl-shaped indentations 21 may be formed in the side wall of the combustion chamber 2, or more specifically in positions facing the respective ignition gaps G1 to G8 on the inner peripheral surface of the opening 13 in the head gasket 8, as shown in FIG. 4 , and the distance L between the ignition gaps G1 to G8 and the side wall of the combustion chamber 2 may be varied according to the position of the electrode pair P1 to P8 by varying a depth d of the indentations 21.
  • the distance L between the ignition gaps G 1 to G8 and the side wall of the combustion chamber 2 is the sum of the projection amount h of the electrode pairs P1 to P8 and the depth d of the indentation 21.
  • the extinguishing action produced by the wall surface of the combustion chamber 2 becomes less likely to be received, and therefore the propagation speed of the flame can be increased. Conversely, when the depth d of the indentation 21 is reduced or the indentation 21 is not provided, the extinguishing action produced by the wall surface of the combustion chamber 2 is more likely to be received, and therefore the propagation speed of the flame can be reduced.
  • the distance L between the ignition gaps G1 to G8 and the side wall of the combustion chamber 2 can be increased further by forming the indentation 21 as well as increasing the projection amount h of the electrode pairs P1 to P8.
  • the projection amount h of electrode pairs such as the electrode pairs P1, P3, P5 and P7 is increased, these electrode pairs interfere with the intake valves 3 or exhaust valves 4, and therefore forming the indentation 21 is also effective when increases in the projection amount h are limited.
  • FIG. 5 shows an example in which the propagation speed of the flames that grow from the ignition gaps G1 to G8 is made uniform by varying only the depth d of the indentation 21 according to the position of the electrode pair P1 to P8 instead of modifying the projection amount h of the electrode pairs P1 to P8.
  • the depth d of the indentations 21 facing the ignition gaps G2, G6 of the electrode pairs P2, P6 disposed near the ridge line X of the pent roof is made greater than the depth d of the indentations 21 facing the ignition gaps G1, G3, G5 and G7, while the depth d of the indentations 21 facing the ignition gaps G4, G8 of the electrode pairs P4, P8 disposed within the squish areas S is made smaller than the depth d of the indentations 21 facing the ignition gaps G1, G3, G5 and G7.
  • the depth d of the indentations 21 facing the ignition gaps G3 to G5 disposed on the exhaust side of the combustion chamber 2 may also be reduced.
  • the extinguishing action produced by the wall surface of the combustion chamber 2 is smaller on the exhaust side than on the intake side due to differences in the wall surface temperature, and therefore, by reducing the depth d of the indentations 21 facing the ignition gaps G3 to G5, the propagation speed of the flames that grow from the ignition gaps G1 to G8 can be made even more uniform.

Landscapes

  • Combustion Methods Of Internal-Combustion Engines (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Spark Plugs (AREA)
EP20070021927 2007-08-01 2007-11-12 Dispositif d'allumage multi-points Active EP2020714B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2007200420A JP4079989B1 (ja) 2007-08-01 2007-08-01 多点点火装置
JP2007203846A JP4139849B1 (ja) 2007-08-06 2007-08-06 多点点火装置

Publications (3)

Publication Number Publication Date
EP2020714A2 true EP2020714A2 (fr) 2009-02-04
EP2020714A3 EP2020714A3 (fr) 2011-12-21
EP2020714B1 EP2020714B1 (fr) 2013-01-16

Family

ID=39870593

Family Applications (1)

Application Number Title Priority Date Filing Date
EP20070021927 Active EP2020714B1 (fr) 2007-08-01 2007-11-12 Dispositif d'allumage multi-points

Country Status (1)

Country Link
EP (1) EP2020714B1 (fr)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535735A (en) * 1981-05-09 1985-08-20 Nippon Soken, Inc. Multi-gap spark ignition system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4535735A (en) * 1981-05-09 1985-08-20 Nippon Soken, Inc. Multi-gap spark ignition system

Also Published As

Publication number Publication date
EP2020714B1 (fr) 2013-01-16
EP2020714A3 (fr) 2011-12-21

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