EP0635856B1 - Zündspule - Google Patents

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Publication number
EP0635856B1
EP0635856B1 EP94109288A EP94109288A EP0635856B1 EP 0635856 B1 EP0635856 B1 EP 0635856B1 EP 94109288 A EP94109288 A EP 94109288A EP 94109288 A EP94109288 A EP 94109288A EP 0635856 B1 EP0635856 B1 EP 0635856B1
Authority
EP
European Patent Office
Prior art keywords
permanent magnet
iron core
ignition coil
cross
sectional area
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
EP94109288A
Other languages
English (en)
French (fr)
Other versions
EP0635856A1 (de
Inventor
Tetsuya Miwa
Yasuo Tsuzuki
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.)
Denso Corp
Original Assignee
Denso 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 Denso Corp filed Critical Denso Corp
Publication of EP0635856A1 publication Critical patent/EP0635856A1/de
Application granted granted Critical
Publication of EP0635856B1 publication Critical patent/EP0635856B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/12—Ignition, e.g. for IC 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
    • F02P1/00—Installations having electric ignition energy generated by magneto- or dynamo- electric generators without subsequent storage

Definitions

  • the present invention relates to a method of operating an improved ignition coil mainly used for internal combustion engines for vehicles.
  • Document EP-A-0 352 453 discloses an ignition coil, wherein an iron core is provided with an air gap additionally having a permanent magnet disposed in the air gap portion.
  • the thickness of the permanent magnet inserted in the air gap portion is between 0.6 - 1.8 mm
  • the ratio of the cross-sectional area of the permanent magnet supporting portion SG and the cross-sectional area of the iron core SF is between 1.5 and 4.5
  • the ratio of the cross-sectional area of the permanent magnet SM and the cross-sectional area of the iron core SF is between 2 and 6.
  • the iron core Prior to the energization of the primary coil, the iron core is magnetized by a magnetizing force of the permanent magnet inserted in the air gap portion in order to reach a state of a maximum working magnetic flux density in the negative direction which is opposite to the direction of the magnetization to be caused by the energization of the primary coil, in particular.
  • the permanent magnet biases the magnetization to the negative saturation point of 1.5 T to obtain the maximum energy.
  • the secondary voltage will be reduced, when the primary current is reduced below 3.5 A which is more likely, when the primary winding resistance is higher than 1 Ohm.
  • the output voltage of an ignition coil having a permanent magnet is clearly less than that of an ignition coil not being equipped with a permanent magnet, specifically in a primary current range lower than 3 A. Due to the corresponding magnetic saturation, this results in an output performance degradation.
  • Fig. 6 is a schematic view showing a fundamental magnetic circuit of an iron core which has a permanent magnet inserted into an air gap portion of an ignition coil according to the above European Patent Application.
  • reference mark SF is a cross-sectional area of the iron core through which magnetic flux ⁇ flows
  • SG is a cross-sectional area of a permanent magnet supporting portion of the iron core
  • LF is a mean magnetic path length
  • SM is a cross-sectional area of the permanent magnet which is hatched
  • LM is a thickness of the permanent magnet.
  • Figs. 7 and 8 are performance characteristic diagrams for illustrating the magnetic performance of the ignition coil according to the above European Patent Application.
  • a curve (a) represents a magnetization characteristic of the iron core
  • a straight line (b) represents a magnetization characteristic of the permanent magnet
  • a curve (c) represents a magnetization characteristic of the primary winding.
  • the maximum working magnetic flux density BF of the iron core is given by a value corresponding to a point T which is a tangent point on the curve (a) with a straight line being parallel to the straight line (b) as a resultant summation of (a) and (b).
  • the gradient of the magnetization curve of the primary winding is determined by the permeability ⁇ of the permanent magnet, it is of significance that a permanent magnet material which has a permeability value close to 1 should be selected in order to increase the energy stored in the primary winding represented by a hatched area W in Fig. 8, so that the permeability value close to 1 may contribute as an air gap which stores energy and to decline the magnetization curve of the primary winding shown in Fig. 8.
  • the magnetizing force nIp/2 produced by an exciting current flowing through the primary winding is the resultant of a magnetizing force HF ⁇ LF of the iron core (where HF is a magnetic field in the iron core) and a magnetizing force H ⁇ LM across the air gap portion containing the permanent magnet (where H is a magnetic field generated in the air gap portion).
  • Ip means the maximum primary winding current, that is, the current under normal operation.
  • nIp/2 HF ⁇ LF + H ⁇ LM
  • H (nIp/2 - HF ⁇ LF)/LM [AT/m]
  • BG ⁇ SG BF ⁇ SF
  • BM ⁇ SG BF ⁇ SF .
  • LM [SG/SF] ⁇ [ ⁇ (nIp/2 - HF ⁇ LF)/BF]
  • the iron core In the negative flux region of the hatched region in the performance characteristic curve diagram of Fig. 8, the iron core is required to be magnetized by a magnetizing force of the primary winding in opposition to energy possessed by the permanent magnet, so that a positive flux may pass through the iron core. Therefore, the iron core is first magnetized to the point P close to the saturation point in the negative flux region of the iron core depicted in the lower left region in Fig. 8 by the magnetizing force of the permanent magnet as described previously. Thereafter the iron core is magnetized to the point T near the saturation point in the positive flux region depicted at an upper right region in Fig. 8 by the magnetizing force nIp due to the exciting current Ip through the primary winding.
  • the maximum energy product of a permanent magnet is expressed as (B ⁇ H) MAX.
  • an operating point of the permanent magnet to be determined by the gradient of the magnetization curve (b) of the permanent magnet shown in Fig. 9 is chosen the point which gives the maximum energy product (B ⁇ H) MAX. or which is around such optimum point.
  • SmCo5 sinarium cobalt
  • the iron core is formed of non-oriented silicon steel plates and the value of the elements therefore are as follows.
  • Figs. 10 and 11 Illustrated in Figs. 10 and 11 is a secondary voltage V2 generated in the secondary winding which is obtained from performance tests conducted for various ignition coils which have different dimensions of individual portions depending on the changes in thickness LM of the permanent magnet.
  • Fig. 11 shows distribution curves of the secondary voltage V2 shown in Fig. 10 after converting them into a two-dimensional characteristic curve and as a relationship between the thickness LM of the permanent magnet and the magnitude of the secondary voltage V2.
  • Figs. 15 and 16 show cross-sectional and side views of another conventional ignition coil which has no permanent magnet, respectively.
  • Figs. 17 and 18 respectively show the cross-sectional and side views of the ignition coil which utilizes the permanent magnet according to the above prior art 1.
  • the ignition coil applied with the permanent magnet may drastically realize a small size (see the typical dimension values in the Figures) and light weight (190 grams) ignition coil compared with the prior art (350 grams) which has no permanent magnet.
  • the ignition coil in the prior art described hereinabove and illustrated in Fig. 17 is mostly effective in a highly sophisticated ignition system which may supply 6A (Amperes) drive current constantly to the primary winding which has less than one ohm resistance even in a case when a battery voltage dropped below the specified value as to maximize the magnetic flux density.
  • 6A Amperes
  • the relationship between the primary cut-off current and secondary output voltage (I1-V2) of the ignition coil in the prior art which has no permanent magnet but has the same secondary output voltage at the same primary current of 6A is graphically compared in Fig. 12 by a solid and dotted lines respectively.
  • the output performance at around 3A primary current range becomes very important, particularly in an engine cranking time under high temperature and low battery voltage.
  • the thickness LM of a permanent magnet and SM/SF ratio between two cross-sectional areas SM and SF are chosen as follows so that the working magnetizing zone of a primary winding does not reside in the curved zone of the magnetization characteristics in the negative region as illustrated in Fig. 4. 0.6 mm ⁇ LM ⁇ 1.8 mm and 1.3 ⁇ SM/SF ⁇ 3.0
  • Fig. 1 is a sectional view of an ignition coil according to an embodiment of this invention and Fig. 2 is a side view of the same.
  • an iron core 1 is made by laminated non-oriented silicone steel sheets and forms a closed magnetic flux circuit via an air gap 2 diagonally arranged in the iron core 1.
  • a permanent magnet 4 is inserted into the air gap 2 of the iron core 1.
  • a primary winding 6 is wound on the iron core 1.
  • the permanent magnet 4 is magnetized in the opposite direction to the direction of magnetization by the exciting current flowing through the primary winding 6.
  • Electrical resistance of the primary winding 6 in case of this embodiment is made to be more than 1 ohm.
  • a secondary winding 8 is wound on the primary winding 6.
  • the mutual relationship between of thickness LM of the permanent magnet 4, diagonal cross-sectional area SM of the permanent magnet 4 and non-diagonal or normal cross-sectional area SF of the iron core 1 at the winding portion is selected to satisfy the following condition.
  • the diagonal cross-sectional area SG of the iron core 1 at the air gap portion is so formed as to be nearly equal to the cross-sectional are SM of the permanent magnet 4. 0.6 mm ⁇ LM ⁇ 1.8 mm 1.3 ⁇ SM/SF ⁇ 3.0
  • Thickness LM of the permanent magnet 4 of the present invention is selected within the same range (0.6 mm ⁇ LM ⁇ 1.8 mm) of that of the prior art, because this range provides maximum secondary voltage V2 as indicated in Fig. 11.
  • the new condition that is, 2/3 times factor which has been discussed in detail should be added to the above condition, then it makes concluded allowable lower and upper limit of the ratio SM/SF as follows. 1.3 ⁇ SM/SF ⁇ 3.0
  • the ignition coil of the present invention may use its straight line portion as the magnetization curve for the primary winding 6 by the introduction of the 2/3 factor and SM/SF ratio of 1.5.
  • the stored energy W' 1.5 on the lower current range is approximately equal to the energy W' of ignition coil which has no permanent magnet.
  • Fig. 5 shows that there is no difference in the secondary output voltage V2 versus cut-off current of the primary winding 6 of both ignition coils of the present invention and the prior art which has no permanent magnet.
  • the ignition coil which is most small in size without degrading performance under low primary current.
  • the ignition coil includes an iron core 1 forming a closed magnetic circuit through an air gap 2 , a primary winding 6 wound around the iron core 1 for magnetizing the iron core 1 and a permanent magnet 4 magnetized in an opposite direction to a magnetizing direction by the primary winding current.
  • a cross-sectional area SG of the iron core 1 at which the permanent magnet 4 is inserted is made substantially equal to that SM of the permanent magnet 4 .
  • the permanent magnet 4 In order for the permanent magnet 4 to bias by 2/3 of the magnetic flux saturation point of the iron core 1 , the permanent magnet 4 is so shaped that its thickness LM satisfies 0.6 mm ⁇ LM ⁇ 1.8 mm and its cross-sectional area SM and the cross-sectional area SF of winding portion of the iron core 1 satisfies 1.3 ⁇ SM/SF ⁇ 3.0 .

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

Claims (5)

  1. Verfahren zum Betreiben einer Zündspule der Bauart mit,
    einem einen geschlossenen magnetischen Kreis über einen darin vorgesehenen Luftspalt (2) aufweisenden Eisenkern (1),
    einer auf dem Eisenkern gewickelten Primärwicklung (6) zur Magnetisierung des Eisenkerns bei einer Versorgung mit elektrischem Strom,
    einer auf dem Eisenkern (1) gewickelten Sekundärwicklung (8),
    einem in den Luftspalt (2) des Eisenkerns (1) eingefügten und in einer Gegenrichtung zu einer Magnetisierungsrichtung infolge der Versorgung der Primärspule (6) mit elektrischem Strom magnetisierten Dauermagneten (4), wobei eine Querschnittsfläche (SG) des Eisenkerns, bei der der Dauermagnet eingefügt ist, im wesentlichen gleich einer Querschnittsfläche (SM) des Dauermagneten (4) ist und eine Dicke (LM) des Dauermagneten innerhalb eines Bereiches von 0,6 mm bis 1,8 mm liegt, und
    wobei die Primärwicklung einen primärseitigen Widerstand größer als 1 Ohm aufweist und ein Verhältnis (SM/SF) zwischen der Querschnittsfläche (SM) des Dauermagneten (4) und einer Querschnittsfläche (SF) des Eisenkerns (1), bei der die Wicklungen aufgewickelt sind, innerhalb eines Bereiches von 1,3 bis 3,0 liegt,
    wobei im Betrieb der Maximalwert des durch die Primärwicklung zur Sättigungsmagnetisierung des Eisenkerns fließenden Stroms eine Magnetisierungsstärke in dem Eisenkern bewirkt, die der Magnetisierungsstärke infolge des Dauermagneten entgegengerichtet und wertmäßig 1,5-fach größer ist.
  2. Verfahren zum Betreiben einer Zündspule der Bauart mit,
    einem einen geschlossenen magnetischen Kreis über einen darin vorgesehenen Luftspalt (2) aufweisenden Eisenkern (1),
    einer auf dem Eisenkern gewickelten Primärwicklung (6) zur Magnetisierung des Eisenkerns bei einer Versorgung mit elektrischem Strom,
    einer auf dem Eisenkern (1) gewickelten Sekundärwicklung (8),
    einem in den Luftspalt (2) des Eisenkerns (1) eingefügten und in einer Gegenrichtung zu einer Magnetisierungsrichtung infolge der Versorgung der Primärspule (6) mit elektrischem Strom magnetisierten Dauermagneten (4), wobei eine Querschnittsfläche (SG) des Eisenkerns, bei der der Dauermagnet eingefügt ist, im wesentlichen gleich einer Querschnittsfläche (SM) des Dauermagneten (4) ist und eine Dicke (LM) des Dauermagneten innerhalb eines Bereiches von 0,6 mm bis 1,8 mm liegt, und
    wobei die Primärwicklung (6) mit einem außerhalb angeordneten Widerstand verbunden ist, der in Verbindung mit der Primärwicklung einen primärseitigen Widerstand größer als 1 Ohm bereitstellt, und ein Verhältnis (SM/SF) zwischen der Querschnittsfläche (SM) des Dauermagneten (4) und einer Querschnittsfläche (SF) des Eisenkerns (1), bei der die Wicklungen aufgewickelt sind, innerhalb eines Bereiches von 1,3 bis 3,0 liegt,
    wobei im Betrieb der Maximalwert des durch die Primärwicklung zur Sättigungsmagnetisierung des Eisenkerns fließenden Stroms eine Magnetisierungsstärke in dem Eisenkern bewirkt, die der Magnetisierungsstärke infolge des Dauermagneten entgegengerichtet und wertmäßig 1,5-fach größer ist.
  3. Verfahren zum Betreiben einer Zündspule nach Anspruch 1 oder 2, wobei die Zündspule für eine Brennkraftmaschine eines Automobils verwendet wird.
  4. Verfahren zum Betreiben einer Zündspule nach Anspruch 3, wobei eine Permeabilität (µ) des Dauermagneten (4) im wesentlichen den Wert 1 aufweist, der Dauermagnet (4) Samarium und Kobalt umfaßt, und der Eisenkern (1) nichtorientierte Silizium-Stahl-Platten umfaßt.
  5. Verfahren zum Betreiben einer Zündspule nach Anspruch 1 oder 2, wobei die Magnetisierung in der Gegenrichtung durch den Dauermagneten (4) auf den Wert 1,0 T beschränkt ist.
EP94109288A 1993-06-18 1994-06-16 Zündspule Expired - Lifetime EP0635856B1 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP14793693 1993-06-18
JP147936/93 1993-06-18
JP14793693A JP3391049B2 (ja) 1993-06-18 1993-06-18 点火コイル

Publications (2)

Publication Number Publication Date
EP0635856A1 EP0635856A1 (de) 1995-01-25
EP0635856B1 true EP0635856B1 (de) 2000-09-13

Family

ID=15441417

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94109288A Expired - Lifetime EP0635856B1 (de) 1993-06-18 1994-06-16 Zündspule

Country Status (4)

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EP (1) EP0635856B1 (de)
JP (1) JP3391049B2 (de)
KR (1) KR100242545B1 (de)
DE (1) DE69425853T2 (de)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3031158U (ja) * 1996-05-14 1996-11-22 阪神エレクトリック株式会社 内燃機関用点火コイル
JP4410196B2 (ja) * 2006-01-31 2010-02-03 三菱電機株式会社 内燃機関用点火コイル装置
US20190277214A1 (en) * 2018-03-12 2019-09-12 Diamond Electric Mfg. Corporation System and method for boosted non-linear ignition coil

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE656392C (de) * 1936-02-27 1938-02-04 Magnetos R B Soc D Zuendspule
DE1464202A1 (de) * 1962-02-23 1969-05-22 Licentia Gmbh Permanentvormagnetisiertes induktives Element
DE7924989U1 (de) * 1979-09-04 1980-11-13 Brown, Boveri & Cie Ag, 6800 Mannheim Magnetischer Energiespeicher
FR2486160A1 (fr) * 1980-07-04 1982-01-08 Ducellier & Cie Perfectionnement aux bobines d'allumage pour moteurs a combustion interne
EP0352453B1 (de) * 1988-07-28 1993-05-19 Nippondenso Co., Ltd. Zündspule
JP2995763B2 (ja) * 1989-11-10 1999-12-27 株式会社デンソー 点火コイル

Also Published As

Publication number Publication date
JP3391049B2 (ja) 2003-03-31
DE69425853T2 (de) 2001-03-15
JPH0722256A (ja) 1995-01-24
KR950001091A (ko) 1995-01-03
KR100242545B1 (ko) 2000-03-02
DE69425853D1 (de) 2000-10-19
EP0635856A1 (de) 1995-01-25

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