Ignition coil for passing alternating current to a spark plug

Abstract

An ignition coil has a core with a longitudinal axis, a secondary winding extending around the core, a sleeve extending around the core, a primary winding wrapped around the sleeve, and a controller connected to the primary winding so as to oscillate alternating current to said primary winding. The secondary winding has a high-voltage end and a low-voltage end. The primary winding is in spaced longitudinal relationship from the secondary winding. Specifically, the primary winding is located longitudinally away from the high-voltage end of the secondary winding. A bobbin is positioned over and around the core. The secondary winding is wrapped around at least a portion of the bobbin.

Claims

1. An ignition coil comprising: a core; a bobbin positioned over and around said core, said bobbin having a plurality of bays formed adjacent only one end of said bobbin; a secondary winding extending around said core, said secondary winding having a high-voltage end and a low-voltage end, said plurality of bays formed adjacent said high-voltage end of said secondary winding, said secondary winding having turns received in said plurality of bays; a sleeve extending over said core and positioned so as to overlie said bobbin and said secondary winding; a primary winding wrapped around an exterior of said sleeve, said primary winding spaced substantially longitudinally away from said low-voltage end of said secondary winding, said primary winding located longitudinally away from said high-voltage end of said secondary winding, said high-voltage end of said secondary winding being at a bay of said plurality of bays most distant from said primary winding; and a controller connected to said primary winding so as to oscillate alternating current to said primary winding.

2. The ignition coil of claim 1, said core being formed of a ferrite material.

3. The ignition coil of claim 1, said sleeve being integral with said bobbin.

4. The ignition coil of claim 1, said secondary winding having approximately 7000 turns, said primary winding having approximately 6 turns.

5. The ignition coil of claim 1, said high-voltage end of said secondary winding adapted to pass 50,000 volts outwardly thereof.

6. The ignition coil of claim 1, said controller having a MOSFET connected to said primary winding, said MOSFET adapted to oscillate the alternating current to said primary winding.

7. The ignition coil claim 6, said MOSFET passing the alternating current to said primary winding with a resonance of at least 30,000 Hertz and less than 100,000 Hertz.

8. The ignition coil of claim 2, said core being formed of a powdered ferrite material bonded with epoxy.

9. The ignition coil of claim 1, further comprising: a power supply connected to said controller, said power supply being a direct current power supply, said controller converting the direct current power to the oscillating alternating current power.

10. The ignition coil claim 1, further comprising: a socket connected to said high-voltage end of said secondary winding, said socket adapted to electrically connect with a terminal of a spark plug.

11. The ignition coil of claim 1, said controller affixed adjacent an end to said core opposite said high-voltage end of said secondary winding.

12. An ignition system comprising: a direct current power supply; a controller connected to said direct current power supply; a core having a longitudinal axis; a bobbin positioned over and around said core, said bobbin having a plurality of bays formed adjacent only one end of said bobbin; a secondary winding extending around said core and received in said plurality of bays, said secondary winding having a high-voltage end adjacent said only one end of said bobbin and a low-voltage end away from said high-voltage end; a sleeve overlying said bobbin and said core, said primary winding wrapped around said sleeve and located substantially longitudinally away from said high-voltage end of said secondary winding; and a spark plug connected to said high-voltage end of said secondary winding.

13. The ignition system of claim 12, said secondary winding having approximately 7000 turns, said primary winding having approximately 6 turns, said high-voltage end of said secondary winding adapted to pass 50,000 volts outwardly thereof.

14. The ignition system of claim 12, said controller have a MOSFET connected to said primary winding, said MOSFET adapted oscillate the alternating current to said primary winding.

15. The ignition system of claim 14, said MOSFET passing the alternating current to said primary winding with a resonance of at least 30,000 Hertz and less than 100,000 Hertz.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a diagram showing the ignition system in accordance with teachings of the present invention.

(2) FIG. 2 is a cross-sectional view of the ignition coil in association with the present invention.

(3) FIG. 3 is an electrical schematic showing the controller as used in the ignition system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(4) Referring to FIG. 1, there is shown a diagram showing the ignition system 10 of the present invention. The ignition system 10 includes a spark plug 12 having electrodes 14 and 16 at one end thereof. The spark plug 12 includes a terminal 18 at an end of the spark plug 12 opposite the electrodes 14 and 16. The ignition coil 20 of the present invention is directly amounted upon the terminal 18 of the spark plug 12. A controller 22 is positioned at the top of the ignition coil 20 and connected to the ignition coil 20 so as to control the firing of the ignition coil and, as a result, the firing of spark plug 12 such that a spark is generated between the electrodes 14 and 16. A battery 24 is connected to the controller 22 so as to supply direct current to the controller 22. The controller 22 will convert the direct current of the battery 24 into an alternating current to the ignition coil 20. As such, when the ignition coil 20 fires the spark plug 12, the spark will alternate between the electrodes 14 and 16 in accordance with the sine wave pattern of the alternating current. The battery 24 can be a conventional automotive battery, such as a twelve volt battery or a twenty-four volt battery.

(5) FIG. 2 shows the ignition coil 20 in accordance with the teachings of the present invention. The ignition coil 20 includes a core 26, a secondary winding 28, a sleeve 30, a primary winding 32 and the controller 22. A socket 34 is formed at the bottom 36 of the ignition coil 20 so as to directly connect the secondary winding 28 to the terminal 18 of the spark plug 12.

(6) The core 26 extends longitudinally within the interior of the ignition coil 20. The secondary winding 28 extends around the core 26 and the primary winding 32 extends around the core 26. The core is preferably formed of a ferrite material. In particular, this ferrite material can be a powdered ferrite that is bonded with epoxy. The bonding of the ferrite core 26 with epoxy will enhance the ability of the core to work with high frequencies.

(7) In FIG. 2, it can be seen that there is a bobbin 38 onto which the secondary winding 28 is received. The bobbin 38 includes a plurality of bays 40 formed thereon. The secondary winding 28 is positioned within these bays 40. Modern winding technology facilitates the ability to effectively wind the secondary 28 within the bays 40 of the bobbin 38. As such, the previously-described problems associated with prior bay-type bobbins is solved with modern winding technology. In effect, the secondary winding 28 can fill one bay and then move in an indexed manner to the next bay so that the secondary winding effectively fills all of the bays associated with the bobbin 38.

(8) The arrangement of the bays 28 is a significant improvement over progressive winding technology. As stated hereinbefore, the problem with the progressive winding is the risk that the progressive winding will slip along the length of the bobbin during the manufacturing process. As such, the progressive winding may not be in the most desired position within the ignition coil. This can result in a failure or in adequate performance of the ignition coil. Since each of the bays 40 of the ignition coil 20 of the present invention are separated by flanges 42, these flanges will effectively retain the windings within the bays so as to assure that such slippage of the secondary winding will not occur.

(9) In FIG. 2, it can be seen that the secondary winding 28 has a high-voltage end 44 and a low voltage end 46. The primary winding 32 is in spaced longitudinal relationship from the high-voltage end 44 of the secondary winding 28. The primary winding 32 is also longitudinally spaced from the low voltage end 46 of the secondary winding 28. Because of this separation, the primary winding 32 will be separated from the low voltage end 46 of the secondary winding 28 so that the problems associated with the deterioration of dielectrics is avoided. This avoids high-voltage flow through any dielectric material which could deteriorate the dielectric and result in an early failure of performance of the ignition coil.

(10) In FIG. 2, the sleeve 30 will extend around the bobbin 34. Within the concept of the present invention, the primary winding 32 could extend over the upper portion 50 of the bobbin 38. In another embodiment, the bobbin 34 can have the portion 50 as a reduced diameter section and the sleeve 30 positioned over such a reduced diameter portion. As such, in the concept of the present invention, it is very important that the primary winding 32 be longitudinally spaced away from the low-voltage end 46 and the high-voltage end 44 of the secondary winding 28.

(11) It can be seen in FIG. 2 that the primary winding 32 has six turns. The secondary winding 28 will have approximately 7,000 turns. As such, when the alternating current is applied by the controller 22 to the primary winding 32, the secondary winding 28 can produce 50,000 volts that for discharge through the socket 32 to the terminal of the spark plug.

(12) A potting material 54 can be placed over the primary winding 32 and over the secondary winding 28. This potting material serves to fix the position of the windings and to prevent damage to the windings. The housing 56 can be placed over the potting material 54 so as to enclose the interior of the ignition coil 20. The controller 22 is positioned at a top of the housing 56.

(13) FIG. 3 illustrates a schematic showing the controller 22. In particular, the controller 22 has an output 60 that is connected to the primary winding 32 of the ignition coil 20. Importantly, there are a pair of MOSFETs 62 and 64 that operate, in conjunction, so as to control the oscillating flow of alternating current to the primary winding 32. The MOSFET is a type of transistor that is used for amplifying or switching electronic signals. The MOSFET is a four-terminal device with a source terminal, a gate terminal, a drain terminal, and a body terminal. The body of the MOSFET is connected to the source terminal so as to make it a three-terminal device such as other field-effect transistors. Because these two terminals are normally connected to each other (short-circuited) internally, only three terminals appear in electrical diagrams. The MOSFET is preferred over a regular transistor in that it requires very little current to turn on (less than one mA), while delivering a much higher current to a load (10 to 50 A or more). As such, the MOSFETs 62 and 64 can serve to switch on the alternating current flow to the primary winding 32 so as to effectively fire the spark plug when fuel is directly injected into the cylinder. The MOSFETs 62 and 64 can remain in on condition for a fixed period of time by the integrated circuit 66 for the period of time desired for the burning of the fuel in the cylinder. As such, if the fuel-burning is to be for five milliseconds, then the one of the MOSFETs 62 and/or 64 can be turned on so as to effectively cause the spark from the spark plug to produce 50,000 volts for five milliseconds for the effective burning of the fuel. The integrated circuit 66 can include a clock so as to be connected to the engine management software such that the desired firing duration can be achieved. The integrated circuit 66 is connected to the battery at terminal 68 so as to effectively received the direct current from the battery. The circuitry shown in FIG. 3 can include suitable DC-to-AC conversion so that the MOSFETs 62 and 64 deliver alternating current to the primary winding to the primary winding 32.

(14) The present invention provides a superior ignition coil for use in turbo-charged direct injection engines. Since these direct injection engines require fuel to be injected of a precise time, the controller 22 is adapted to fire the ignition coil, and the associated spark plug, at the precise time of fuel injection. The timing circuitry will cause the spark plug to remain at maximum power for the duration of the firing of the fuel. As such, the present invention provides a larger window with which to fire the fuel after it has been injected. This is particularly beneficial when diesel engines have been converted into natural gas-burning engines. The present invention provides a compact ignition coil for the limited space that is available in association with such conversions.

(15) In the present invention, the high-voltage end 44 of the secondary winding 28 can transmit 50,000 volts. The primary 32 is located away from this secondary winding. As such, there will be no voltage between the primary winding in the secondary winding. In the past, this has been a troublesome spot since the dielectric between the high-voltage and the low-voltage can deteriorate over a period of time. The ferrite that is used for the core 26 is non-conductive. As such, once again, there is no voltage that is transmitted between the primary winding and the secondary winding. In other words, the 50,000 volts will not conducted through the core 26. As such, there is no need for insulation or dielectrics in association with the ignition coil 20 of the present invention. The ferrite core is used instead of a steel core (which can conduct).

(16) The secondary winding 28 has, preferably, approximately 7000 turns. These turns are isolated in each of the bays 40. The bays provide a form which effectively holds the winding. Alternatively, the secondary windings 28 can be wound directly upon the core 26. Still further, and alternatively, the secondary winding 28 can be wound around a sleeve directly over the ferrite core 26.

(17) When the bays 40 are used, the flanges 42 associated with these adjacent bays 40 serve to keep the secondary winding from sliding. This causes the winding process to be slower. However, this avoids the problems associated with the slippage of the winding that is associated with progressive windings.

(18) The controller 22 provides proper oscillation, by way of the MOSFETs 62 and 64, so as to drive the power to the ignition coil. The oscillator takes the direct current (either 12 volts or 24 volts) with the MOSFETs 62 and 64 and serves to adjust the frequency of the resonance. Maximum amplitude is believed to be achieved at 30,000 Hertz. The arcing of the spark plug will occur at 90,000 Hertz. The circuitry effectively turns the direct current into an alternating current sine wave. As such, the present invention provides constant alternating current across the spark plug. The spark plug will have full power during the entire duration of the spot. The MOSFETs requires virtually no current or voltage in order to switch on and off.

(19) The alternating of the current across the electrodes of the spark plug effectively avoids deterioration of the electrodes. Since the spark plug fires from a first electrode to a second electrode during a positive portion of the sine wave and fires from the second electrode to the first electrode during the negative part of sine wave, any deterioration of the electrodes is effectively avoided by this constant switching.

(20) The resonance is achieved for maximum voltage. This maximum voltage occurs at 30,000 Hertz. If over 100,000 Hertz is achieved, then this could affect radio frequencies and, as a result, the quality of the radio performance. The resonance achieved by the oscillation of the alternating current provides the maximum amount of power from the minimal input.

(21) Within the concept of the present invention, it is possible to pulse the alternating current during the firing of the spark plug. The pulsing of the alternating current allows for the fuel/air mixture to escape from the cylinder in a more uniform manner. It is possible that the fuel/air mixture could get hung up in the spark gap. Since a high frequency is generated in this gap, there is possibility that this high-frequency could contain the fuel/air mixture in this gap and somewhat negatively affect the escape of the completely burned fuel/air mixture. By the pulsing of the alternating current and the association of this pulsed alternating current with the electrodes of the spark plug, the gathering of the fuel/air mixture in the spark gap is effectively avoided.

(22) The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction can be made within the scope of the appended claims without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.