CA1094149A - Ignition coils - Google Patents
Ignition coilsInfo
- Publication number
- CA1094149A CA1094149A CA283,556A CA283556A CA1094149A CA 1094149 A CA1094149 A CA 1094149A CA 283556 A CA283556 A CA 283556A CA 1094149 A CA1094149 A CA 1094149A
- Authority
- CA
- Canada
- Prior art keywords
- coil
- gap
- ignition
- windings
- primary
- 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
Links
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
- F02P9/00—Electric spark ignition control, not otherwise provided for
- F02P9/002—Control of spark intensity, intensifying, lengthening, suppression
- F02P9/007—Control of spark intensity, intensifying, lengthening, suppression by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Ignition Installations For Internal Combustion Engines (AREA)
Abstract
Abstract of the Disclosure A double coil ignition system which is operated from separate opto-electronic triggers, the secondary windings of the two coils being connected to supply energy to the same spark plug or distributor system, the first coil providing a high voltage discharge in order to ionize the gap across the spark plug and the second coil providing a low voltage high current discharge at a given crank-shaft position after the first coil has ionized the gap, the second coil thus delivering a high current across the gap to ensure the complete combustion of lean fuel mixtures.
Description
The present invention relates to improvements in ignition coils.
It is well known tha~ energy is delivered by the secondary winding o~ the ignition coil at a high voltage, but comparatively low current. It is a characteristic of spark plugs that they rcquire a much ~igher voltage to achieve the initial ionization of the electrode gap, than they need to maintain the current flow across the gap once ionization has taken place.
This di~ference in voltage is roughly 6,000 volts to 1,000 volts for a warm engine, but may rise to as much as 17,000 volts to 1,000 volts in a cold engine.
Since modern internal combustion engines are required to burn leaner mixtures at large spark advance angles, in order to produce low emission levels, the standard ignition coil is no longer able to supply the high spark energy required for these conditions of operation.
It has already been proposed to overcome the above problem by providing an ignition system having two coils, the first coil providing a high voltage in order to ionize the gap across the electrodes of the spark plug whilst the second coil is initiated a short time later to provide a low voltage high energy discharge across the already ionized gap.
One such system for achieving this double discharge across the gap is disclosed in British Patent No. 695,4~2 ~Rolls Royce Ltd.). The disclosure in this patent shows the use of two separa~e coils, the secondary winding of the high voltage coil being connected across an auxiliary and main gap provided in series. Whilst the secondary winding of the low voltage coil is connected across the main gap only through a diode.
The disadvantage of the ignition system disclosed in British Patent No. 695,442 is that the high voltage coil has to ionize two gaps. Also whilst the diode prevents currenk from the high voltage secondary winding from feed-.
' -1- ~
,.~
, ; . :, `
, "
ing back to the low voltage secondary winding, there is nothing to prevent current flow in the other direction and this could happen once the voltage across the secondary winding of the high voltage coil has decayed below the level of the voltage across the secondary winding of the low voltage coil since the auxiliary gap would still be ionized.
It is an object of the present invention to overcome partially or wholly disadvantages e~hibited by prior art systems.
According to the present invention, there is provided an ignition systcm for an internal combustion engine said system including: a first ignition coil ha~ing a high tuxns ratio between its secondary and primary windings; a second ignition coil having a relatively low turns ratio between its secondary and primary windings in comparison with the first coil; means for supplying the voltage generated in the two secondary windings to tne same distributor system or spark plug of the internal combustion engine; means for electrically isolating the two secondary windings; first means for switch-ing off the current in the primary winding of said first ignition coil in order to produce a high voltage to ionize the gap across the spark plug;
second means for switching off the current in the primary winding of said s0cond ignition coil at a constant predetermined crank-shaft position after the current in the primary winding of the first coil has been switched off, in order to maintain the voltage across the gap so as to provide a long spark duration.
In this arrangement, the energy provided by the first secondary winding ionizes the gap across the spar~ plug, and then both the secondary windings supply spark energy simultaneously for 2-3 milliseconds once the spark ~ap has been ionized~ the second secondary winding supplying the majority of the energy necessary to sustain the spark once the gap has been ionized.
It is well known tha~ energy is delivered by the secondary winding o~ the ignition coil at a high voltage, but comparatively low current. It is a characteristic of spark plugs that they rcquire a much ~igher voltage to achieve the initial ionization of the electrode gap, than they need to maintain the current flow across the gap once ionization has taken place.
This di~ference in voltage is roughly 6,000 volts to 1,000 volts for a warm engine, but may rise to as much as 17,000 volts to 1,000 volts in a cold engine.
Since modern internal combustion engines are required to burn leaner mixtures at large spark advance angles, in order to produce low emission levels, the standard ignition coil is no longer able to supply the high spark energy required for these conditions of operation.
It has already been proposed to overcome the above problem by providing an ignition system having two coils, the first coil providing a high voltage in order to ionize the gap across the electrodes of the spark plug whilst the second coil is initiated a short time later to provide a low voltage high energy discharge across the already ionized gap.
One such system for achieving this double discharge across the gap is disclosed in British Patent No. 695,4~2 ~Rolls Royce Ltd.). The disclosure in this patent shows the use of two separa~e coils, the secondary winding of the high voltage coil being connected across an auxiliary and main gap provided in series. Whilst the secondary winding of the low voltage coil is connected across the main gap only through a diode.
The disadvantage of the ignition system disclosed in British Patent No. 695,442 is that the high voltage coil has to ionize two gaps. Also whilst the diode prevents currenk from the high voltage secondary winding from feed-.
' -1- ~
,.~
, ; . :, `
, "
ing back to the low voltage secondary winding, there is nothing to prevent current flow in the other direction and this could happen once the voltage across the secondary winding of the high voltage coil has decayed below the level of the voltage across the secondary winding of the low voltage coil since the auxiliary gap would still be ionized.
It is an object of the present invention to overcome partially or wholly disadvantages e~hibited by prior art systems.
According to the present invention, there is provided an ignition systcm for an internal combustion engine said system including: a first ignition coil ha~ing a high tuxns ratio between its secondary and primary windings; a second ignition coil having a relatively low turns ratio between its secondary and primary windings in comparison with the first coil; means for supplying the voltage generated in the two secondary windings to tne same distributor system or spark plug of the internal combustion engine; means for electrically isolating the two secondary windings; first means for switch-ing off the current in the primary winding of said first ignition coil in order to produce a high voltage to ionize the gap across the spark plug;
second means for switching off the current in the primary winding of said s0cond ignition coil at a constant predetermined crank-shaft position after the current in the primary winding of the first coil has been switched off, in order to maintain the voltage across the gap so as to provide a long spark duration.
In this arrangement, the energy provided by the first secondary winding ionizes the gap across the spar~ plug, and then both the secondary windings supply spark energy simultaneously for 2-3 milliseconds once the spark ~ap has been ionized~ the second secondary winding supplying the majority of the energy necessary to sustain the spark once the gap has been ionized.
-2-.
. ~
, . , , :"
- ;.
.
"
.
.
~" ~, . .. .
In a preferred embodiment the electrical isolating means comprises a pair of diodes connected between respective one ends of the secondary windings and the distributor system or one electrode of the spark plug.
The first and second primary current switching means may comprise first and second opto-electronic triggers operated through separate chopper discs driven in synchronism with the engine.
The present invention will now be described in greater detail by way of examples with reference to the accvmpanying drawing, which is a circuit diagram of one preferred form of double ignition coil system according to tlle invention using two opto-electronic triggers for providing high spark energy to an internal combùstion engine operating on a lean fuel mixture.
Referring to the drawing, the ignition system includes ignition coils 1 and 2, having respective primary windings Pl and P2 and respective secondary windings Sl and S2. The primary windings Pl and P2 are colmected in series with respective power transistors Tl and T2 across the 12 volts battery supply o the internal combustion engine. The ends of the secondary windings Sl and S2 not connected to their respective primaries, are connected to a distributor Z through respective diodes Dl and D2. The distributor Z
distributes the energy to the spark plugs 3 in the correct sequence of cylinder firing, in accordance with conventional practice.
; The power transistors Tl and T2 are switched by respective "Lumenition" ~Registered Trade Mark) bistable opto-electronic triggers com-prising respective trigger modules Xl and X2. The trigger modules Xl and X2 are energized from respective photo-transistors Bl and B2, as a result of infra-red radiation from respective gallium arsenide lamps Al and A2 after passillg through the apertures or slots of respective discs Cl and C2, driven in synchronism with the engine.
1 . . .
~ .. , .
.
. . :: , , ., :
. , ': ',, . ~ ,. ' - ., . ,: , :
- .
The primary windings Pl and P2 have about 200 turns, whereas, the secondary windings Sl and S2 respectively have 20,000 turns and 2,000 turns.
The secondary winding S2 is of substantially thicker gauge wire, in order that it has a lower resistance. The open circuit voltages across the second-ary windings Sl and S2 are of the order of 35,000 volts and 3,500 volts respectively.
In the case illustrated in the drawing, the slotted or apertured discs Cl and C2 are arranged so that the disc Cl is set to switch of its associated power transistor Tl a few crankshaft degrees in advance of the switching of the second power transistor T2 by the disc C2. Thus, the power transistor Tl, on switching off, causes a high secondary voltage of 35,000 volts to be developed in the secondary winding Sl, to cause the initlal ionization of the compressed fuel mixture across the spark gap. A few crankshaft degrees later, -the second power transistor T2 switches off, to cause a voltage of 3,500 volts to be developed across the secondary winding S2. Since this secondary winding S2 has larger diameter wire than tlle secondary winding Sl, it can carry a larger current, this current supplement-ing the current flowing in the winding Sl in order to maintain the necessary energy to the spark plug to ensure complete combustion of the lean fuel mix-ture in the cyllnder.
The advantages of the above described system lie in the fact thathigher spark energy will be available in the combustion chamber, thus permitting complete combustion of lean fuel mixtures, whilst ensuring that the spark duration is such that the spark is not present during the combus-tion period.
The present invention is no~ limited to petrol or, or that matter, diesel spark ignition internal combustion engines, and could be equally applicable to iring gas, or even oil, burners in industry.
r ~
~t~
- . .
- , ~ . , .. , . ~ :
- ; -,
. ~
, . , , :"
- ;.
.
"
.
.
~" ~, . .. .
In a preferred embodiment the electrical isolating means comprises a pair of diodes connected between respective one ends of the secondary windings and the distributor system or one electrode of the spark plug.
The first and second primary current switching means may comprise first and second opto-electronic triggers operated through separate chopper discs driven in synchronism with the engine.
The present invention will now be described in greater detail by way of examples with reference to the accvmpanying drawing, which is a circuit diagram of one preferred form of double ignition coil system according to tlle invention using two opto-electronic triggers for providing high spark energy to an internal combùstion engine operating on a lean fuel mixture.
Referring to the drawing, the ignition system includes ignition coils 1 and 2, having respective primary windings Pl and P2 and respective secondary windings Sl and S2. The primary windings Pl and P2 are colmected in series with respective power transistors Tl and T2 across the 12 volts battery supply o the internal combustion engine. The ends of the secondary windings Sl and S2 not connected to their respective primaries, are connected to a distributor Z through respective diodes Dl and D2. The distributor Z
distributes the energy to the spark plugs 3 in the correct sequence of cylinder firing, in accordance with conventional practice.
; The power transistors Tl and T2 are switched by respective "Lumenition" ~Registered Trade Mark) bistable opto-electronic triggers com-prising respective trigger modules Xl and X2. The trigger modules Xl and X2 are energized from respective photo-transistors Bl and B2, as a result of infra-red radiation from respective gallium arsenide lamps Al and A2 after passillg through the apertures or slots of respective discs Cl and C2, driven in synchronism with the engine.
1 . . .
~ .. , .
.
. . :: , , ., :
. , ': ',, . ~ ,. ' - ., . ,: , :
- .
The primary windings Pl and P2 have about 200 turns, whereas, the secondary windings Sl and S2 respectively have 20,000 turns and 2,000 turns.
The secondary winding S2 is of substantially thicker gauge wire, in order that it has a lower resistance. The open circuit voltages across the second-ary windings Sl and S2 are of the order of 35,000 volts and 3,500 volts respectively.
In the case illustrated in the drawing, the slotted or apertured discs Cl and C2 are arranged so that the disc Cl is set to switch of its associated power transistor Tl a few crankshaft degrees in advance of the switching of the second power transistor T2 by the disc C2. Thus, the power transistor Tl, on switching off, causes a high secondary voltage of 35,000 volts to be developed in the secondary winding Sl, to cause the initlal ionization of the compressed fuel mixture across the spark gap. A few crankshaft degrees later, -the second power transistor T2 switches off, to cause a voltage of 3,500 volts to be developed across the secondary winding S2. Since this secondary winding S2 has larger diameter wire than tlle secondary winding Sl, it can carry a larger current, this current supplement-ing the current flowing in the winding Sl in order to maintain the necessary energy to the spark plug to ensure complete combustion of the lean fuel mix-ture in the cyllnder.
The advantages of the above described system lie in the fact thathigher spark energy will be available in the combustion chamber, thus permitting complete combustion of lean fuel mixtures, whilst ensuring that the spark duration is such that the spark is not present during the combus-tion period.
The present invention is no~ limited to petrol or, or that matter, diesel spark ignition internal combustion engines, and could be equally applicable to iring gas, or even oil, burners in industry.
r ~
~t~
- . .
- , ~ . , .. , . ~ :
- ; -,
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An ignition system for an internal combustion engine said system including: a first ignition coil having a high turns ratio between its secondary and primary windings; a second ignition coil having a relatively low turns ratio between its secondary and primary windings in comparison with the first coil; means for supplying the voltage generated in the two secondary windings to the same distributor system or spark plug of the internal combustion engine; means for electrically isolating the two second-ary windings; first means for switching off the current in the primary wind-ing of said first ignition coil in order to produce a high voltage to ionize the gap across the spark plug; second means for switching off the current in the primary winding of said second ignition coil at a constant predeter-mined crank-shaft position after the current in the primary winding of the first coil has been switched off, in order to maintain the voltage across the gap so as to provide a long spark duration.
2. An ignition system according to claim 1, wherein said electrical isolating means comprises a pair of diodes connected between respective one ends of the secondary windings and the distributor system or one electrode of the spark plug.
3. An ignition system according to claim 1, wherein said first and second primary current switching means comprise first and second opto-electronic triggers operated through separate chopper discs driven in synchro-nism with the engine.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB32045/76 | 1976-08-02 | ||
| GB32045/76A GB1557046A (en) | 1976-08-02 | 1976-08-02 | Ignition systems |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1094149A true CA1094149A (en) | 1981-01-20 |
Family
ID=10332297
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA283,556A Expired CA1094149A (en) | 1976-08-02 | 1977-07-26 | Ignition coils |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5317848A (en) |
| AU (1) | AU511743B2 (en) |
| BR (1) | BR7705064A (en) |
| CA (1) | CA1094149A (en) |
| DE (1) | DE2734034A1 (en) |
| ES (1) | ES461660A1 (en) |
| FR (1) | FR2360764A1 (en) |
| GB (1) | GB1557046A (en) |
| IT (1) | IT1115888B (en) |
| SE (1) | SE420638B (en) |
| ZA (1) | ZA774490B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0291477A (en) * | 1988-09-27 | 1990-03-30 | Mitsubishi Electric Corp | Engine igniter |
| JP2774992B2 (en) * | 1989-10-03 | 1998-07-09 | アイシン精機株式会社 | Ignition device for internal combustion engine |
| DE10021170A1 (en) * | 2000-04-29 | 2001-10-31 | Bosch Gmbh Robert | Ignition system for an internal combustion engine |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1764105A1 (en) * | 1967-04-10 | 1972-02-03 | Bendix Corp | Electric ignition spark generator |
| US3452733A (en) * | 1967-09-13 | 1969-07-01 | Frank B Eckert | Ignition system |
| JPS492809A (en) * | 1972-04-20 | 1974-01-11 | ||
| US3919993A (en) * | 1974-07-10 | 1975-11-18 | Gen Motors Corp | Internal combustion engine coordinated dual action inductive discharge spark ignition system |
| DE2547397C2 (en) * | 1975-10-23 | 1985-01-31 | Robert Bosch Gmbh, 7000 Stuttgart | Electronic ignition system for internal combustion engines |
-
1976
- 1976-08-02 GB GB32045/76A patent/GB1557046A/en not_active Expired
-
1977
- 1977-07-25 ZA ZA00774490A patent/ZA774490B/en unknown
- 1977-07-26 CA CA283,556A patent/CA1094149A/en not_active Expired
- 1977-07-28 FR FR7723268A patent/FR2360764A1/en active Pending
- 1977-07-28 DE DE19772734034 patent/DE2734034A1/en not_active Withdrawn
- 1977-07-29 AU AU27467/77A patent/AU511743B2/en not_active Expired
- 1977-08-01 ES ES461660A patent/ES461660A1/en not_active Expired
- 1977-08-01 SE SE7708762A patent/SE420638B/en unknown
- 1977-08-01 IT IT50528/77A patent/IT1115888B/en active
- 1977-08-02 JP JP9292477A patent/JPS5317848A/en active Pending
- 1977-08-02 BR BR7705064A patent/BR7705064A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5317848A (en) | 1978-02-18 |
| ES461660A1 (en) | 1978-06-16 |
| BR7705064A (en) | 1978-05-02 |
| SE7708762L (en) | 1978-02-03 |
| DE2734034A1 (en) | 1978-02-09 |
| AU2746777A (en) | 1979-02-01 |
| AU511743B2 (en) | 1980-09-04 |
| GB1557046A (en) | 1979-12-05 |
| SE420638B (en) | 1981-10-19 |
| FR2360764A1 (en) | 1978-03-03 |
| ZA774490B (en) | 1978-06-28 |
| IT1115888B (en) | 1986-02-10 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US3910247A (en) | Method and apparatus for distributorless ignition | |
| CA1153792A (en) | Plasma jet ignition system | |
| US20090126710A1 (en) | Dual coil ignition circuit for spark ignited engine | |
| JP2597126B2 (en) | Method and apparatus for generating ignition spark in an internal combustion engine | |
| US6814047B2 (en) | Method of ignition and corresponding ignition unit | |
| JPH0256519B2 (en) | ||
| US4556040A (en) | Distributorless ignition system for multi-cylinder internal combustion engine with misfire suppression | |
| US3980922A (en) | Capacitance discharge type breakerless ignition system for an internal combustion engine | |
| US4613789A (en) | Spark plug with capacitor spark discharge | |
| US4653460A (en) | Ignition system for internal combustion engines | |
| CA1094149A (en) | Ignition coils | |
| US3885541A (en) | Dual ignition coil for internal combustion engine | |
| GB1465839A (en) | Ignition system for internal combustion engines | |
| KR19990014943A (en) | Induction lighting device | |
| RU2126494C1 (en) | Ignition system for dual-spark ignition internal combustion engines | |
| US3100479A (en) | Ignition system for internal combustion engine | |
| US5125387A (en) | Distributorless ignition system | |
| US6666196B2 (en) | Ignition system having improved spark-on-make blocking diode implementation | |
| US5425348A (en) | Distributorless ignition system for an internal combustion engine | |
| US3452733A (en) | Ignition system | |
| US4350137A (en) | Ignition system for internal combustion engines | |
| US6684866B2 (en) | Ignition system for an internal combustion engine | |
| US2779898A (en) | Starting device for internal combustion engines | |
| US4201171A (en) | Ignition system for a multicylinder engine | |
| JP2000009010A (en) | Ignition device for internal combustion engine |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |