Ignition coil having a winding form

Abstract

An ignition coil has a ferromagnetic core, a primary coil surrounding a portion of the core and wrapped helically with a conductor, a winding form having partitions extending outwardly of a tubular surface of the winding form, and a secondary coil wrapped on the winding form. The partitions define a plurality of annular coil chambers including central chambers and end chambers. The end chambers have a spiral land. The secondary coil includes coil sections in each of the plurality of coil chambers. The secondary coil has coil turns in the end chambers in a spiral configuration on the spiral land and increasing progressively in diameter toward the central chambers.

Claims

1. An ignition system comprising: a ferromagnetic core; a primary coil surrounding a portion of said ferromagnetic core, said primary coil being wrapped helically with a conductor; a winding form having partitions extending outwardly of a tubular surface of said winding form, said partitions defining a plurality of annular coil chambers including central chambers and end chambers, said end chambers having a spiral land; and a secondary coil wrapped on said winding form including coil sections in each of said plurality of coil chambers, said second coil having coil turns in said end chambers in a spiral configuration on said spiral land and increasing progressively in diameter toward said central chamber, said end chambers comprising: a first end chamber formed adjacent to one of said central chambers; a second end chamber formed on a side of said first end chamber opposite to said one of said central chambers; a third end chamber formed on a side of said second end chamber opposite said first end chamber; and a fourth end chamber formed on a side of said third end chamber opposite said second end chamber, said fourth end chamber located adjacent an end of said winding form, said fourth end chamber having a greater volume and width than a volume and width of said third end chamber, a bottom of said third end chamber having a radius equal to a radius of a bottom of said fourth end chamber, a bottom of said first end chamber having a radius greater than a radius of a bottom of said second end chamber, a bottom of said second end chamber having a radius greater than a radius of a bottom of said third end chamber.

2. The ignition coil of claim 1, each of said end chambers has a depth less than a depth of said central chambers.

3. The ignition coil of claim 1, the partitions of one of said end chambers having a generally equal diameter.

4. The ignition coil claim 3, the partition of one of said end chambers being adjacent the end of said winding form.

5. The ignition coil of claim 1, the partitions of said end chambers progressively decreasing in radius from said central chambers.

6. The ignition coil claim 1, one of said end chambers having a greater width than another of said end chambers.

7. The ignition coil claim 1, at least two partitions of said end chambers decreasing in diameter from said central chamber toward an end of said winding form.

8. The ignition coil claim 1, said secondary coil having coil turns in which successive turns in said end chambers are axially and radially spaced from one another so as to prevent arcing.

9. An ignition system comprising: a spark plug; a power supply; and an ignition coil connected to said spark plug and to said power supply, said ignition coil comprising: a ferromagnetic core; a primary coil surrounding a portion of the core, said primary coil being wrapped helically with a conductor; a winding form having partitions extending outwardly of a tubular surface of said winding form, said partitions defining a plurality of annular coil chambers including central chambers and end chambers, said end chambers having a spiral land; and a secondary coil wrapped on said winding form and including coil sections in each of said plurality of coil chambers, said secondary coil having coil turns in said end chambers in a spiral configuration on said spiral land and increasing progressively in diameter toward said central chamber, said end chambers comprising: a first end chamber formed adjacent to one of said central chambers; a second end chamber formed on a side of said first end chamber opposite to said one of said central chambers; a third end chamber formed on a side of said second end chamber opposite said first end chamber; and a fourth end chamber formed on a side of said third end chamber opposite said second end chamber, said fourth end chamber located adjacent an end of said winding form, said fourth end chamber having a greater volume and width than a volume and width of said third end chamber, a bottom of said third end chamber having a radius equal to a radius of a bottom of said fourth end chamber, a bottom of said first end chamber having a radius greater than a radius of a bottom of said second end chamber, a bottom of said second end chamber having a radius greater than a radius of a bottom of said third end chamber.

10. The ignition system of claim 9, wherein each of said end chambers have a depth less than a depth of said central chambers.

11. The ignition system of claim 9, the partitions of said end chambers progressively decreasing in radius from said central chamber.

12. The ignition system of claim 9, one of said end chambers having a greater width than another of said end chambers.

13. The ignition system of claim 9, said secondary coil having coil turns in which successive turns in said end chambers are axially and radially spaced from one another so as to prevent arcing.

14. The ignition system of claim 9, each of said partitions having an annular shape, said winding form surrounding said primary coil and said core.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram illustrating a typical ignition system for modern internal combustion engine and including three ignition transformers, one for every two cylinders.

(2) FIG. 2 is a schematic diagram illustrating the ignition system of the present invention as used in association with an electronic control unit and with a single plug in a coil on/over plug configuration.

(3) FIG. 3 is a schematic diagram illustrating the ignition system of the present invention as used in association with a programmable control module and a coil-on/over plug configuration.

(4) FIG. 4 is a schematic diagram illustrating the ignition system of the present invention for use as part of a passive coil in an coil on/over plug configuration.

(5) FIG. 5 is an exploded perspective view shown in the ignition transformer of the present invention.

(6) FIG. 6 is a cross-sectional side elevational view showing the winding form as used in the ignition coil of the present invention.

(7) FIG. 7 is a side elevational view showing the winding form of the ignition coil of the present invention and having turns of coil on the spiral land of the end chambers.

(8) FIG. 8 is a detailed perspective view showing the particular configuration of the end chambers as used on the winding form of the ignition coil of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(9) Referring more particularly to the drawings and initially to FIG. 1, there shown an electronic ignition system typical of those used in modern automotive vehicle engines. The system illustrated is designed for a typical six-cylinder engine where the crankshaft cranks lie in a planar configuration. The system utilizes three separate ignition transformers 11, 12 and 13, one for each of two cylinders that fire at opposite portions of the engine cycle.

(10) The system includes a cam sensor 16 and a crank sensor 17 that input to a control module IS, which connects to the primary windings of the transformers 11, 12 and 13. The primary windings are energized to time the firing of the plugs that are fired by the respective secondary windings. The windings are energized in opposite modes depending upon the particular spark plug to be fired. The plugs for the cylinder pairs are fired sequentially by the secondary coil of the transformer 11.

(11) FIG. 2 is a schematic illustration showing the coil-on/coil-over plug configuration. In particular, the transformer 20 has secondary 22 connected to the plug 24. The ignition coil igniter 26 is connected to the primary 28 of the transformer 20. The transformer 20 and the igniter 26 are contained within an igniter integrated coil assembly 30. The power supply 32 is a battery that can be connected to an electronic control unit 34. The electronic control unit causes the function of and the timing of the coil operation to be based upon information processed by the control unit.

(12) FIG. 3 is a schematic illustrating the transformer 36 as used in association with a coil-on/coil-over plug configuration. In particular, the secondary 38 of the transformer 36 is connected to plug 40. The primary 42 of the transformer 36 can be connected to coil igniter 44. The transformer 36 and the coil igniter 44 are maintained within an igniter integrated coil assembly 46. The power supply is provided by battery 48. A programmable control module 50 provides a signal to the coil igniter 44 so as to control the function of and the timing of the coil operation based on information processed by the control unit.

(13) FIG. 4 shows a passive coil assembly. In particular, the transformer 52 has secondary 54 connected to plug 56. The primary 58 is connected to the electronic control unit 60. A battery 62 provides power to the electronic control unit 60 and, as such, to the primary 54 of the transformer 52.

(14) In the transformers described in FIGS. 1-4, the transformers will be of the type shown hereinafter. The transformer comprises a laminated, ferromagnetic core 70 of a standard construction, a primary coil 71 wrapped on a winding tube 72 that surrounds one portion of the core 70, a secondary coil 73 wrapped on a winding form for bobbin 74 that surrounds and is concentric with the primary coil 71 and the primary winding tube 72.

(15) In FIG. 5, it can be seen that the winding form 74 has a unique configuration. In particular, the winding form has partitions 76 extending outwardly of a tubular surface of the winding form 74. These partitions define a plurality of annular coil chambers including central chambers 78 and end chambers 80. The end chambers 80 have a spiral land. The secondary coil 73 is wrapped on the winding form 74 in each of the plurality of coil chambers 78. The secondary coil 43 has leads 81 and 82 extending therefrom at opposite ends of the winding form 74.

(16) FIG. 6 particularly illustrates the winding form 74. In particular, it can be seen that the partitions 76 extend radially outwardly of a tubular surface 84 of the winding form 74. These partitions define a plurality of annular coil chambers 78 including central chambers 86 and end chambers 88.

(17) In FIG. 6, it can be seen that each of the end chambers 88 has a depth less than a depth of each of the central chambers 86. Each of the partitions 76 of the central chambers 86 extend outwardly of the tubular surface 84 for an approximate equal distance. The end chambers 88 will be adjacent to an end partition 90 of the plurality of central chambers 86.

(18) The winding form 74 of the present invention is of a generally tubular cylindrical form with the outer tubular surface 84. The partitions 76 extend radially in spaced relationship from each other so as to define the plurality of central chambers 86. Each of the plurality of central chambers 86 will receive a plurality of coil turns. The wire is wrapped from one end to the other using coil winding machines at a well known in the art. The coil is passed from one partition to the other through transitions slots (not shown) that extend in a somewhat diagonal direction through the respective partitions 76. The end chambers 88 are adapted to receive three or more turns of wire forming the secondary coil at the end of the winding form 74.

(19) FIG. 7 illustrates the secondary coil 73 as received within the end chambers 88. As can be seen, the partitions in the end chambers 88 form a spiral land for the secondary coil 73. Each of the end chambers 88 receive a single turn of the secondary coil 73. Importantly, it can be seen that there is an end chamber 92 that does not receive a turn of the secondary coil 73 therein. As such, this end chamber 92 will space the turns of the other end chamber from the end partition 94.

(20) FIG. 8 is a detailed view showing the end chambers 88 formed on the winding form 74. FIG. 8 further shows that the winding form 74 is placed over and around the ferromagnetic core 70 and over the primary coil 71. FIG. 8 further shows that the partitions 76 are arranged in spaced parallel relationship to each other and each has a generally equal radius extending outwardly from the tubular surface 84 of the winding form 74. FIG. 8 further shows that the secondary coil 73 generally fills each of the chambers of the central chambers 86 that are defined by the partitions 76.

(21) The end chambers 88 which receive respective turns of the secondary coil 73 have a unique configuration. It can be seen that each of the end chambers 88 has a depth that is less than the depth of each of the central chambers 86. In particular, the respective bottoms of each of the end chambers 86 can be seen as extending radially outwardly for a greater distance than the tubular surface 84 associated with the central chambers 86. It can be seen that partitions 100 and 102 of the end chambers 88 have a generally equal diameter. The partition 100 is adjacent to the end 94 of the winding form 74. The partitions 104, 106 and 102 generally progressively decrease in radius from in a direction away from the central chambers 86. It can be seen that the chamber 108 that is defined by the partitions 100 and 102 has a greater width than the chambers 110, 112 and 114 of the remaining end chambers 88 and, as such, operates as to spacing area.

(22) In particular, the end chambers 88 include a first end chamber 105 that is adjacent to one of the central chambers 86. The first end chamber 105 is defined between the partition 104 and the partition 76. The second end chamber 112 is on the side of the first end chamber 105 opposite to the central chambers 86. The second end chamber 112 is defined between the partitions 104 and 106. The third end chamber 110 is on a side of the second end chamber 112 opposite the first end chamber 105. The third end chamber is defined between the partitions 102 and 106. The fourth end chamber 108 is on a side of the third end chamber 110 opposite to the second end chamber 112. The fourth end chamber 108 is defined between the partitions 100 and 102. The first end chamber 105 has a greater radius than the second end chamber 112. The second end chamber 112 has a greater radius than the third end chamber 110. The fourth end chamber 108 has a greater volume than each of the first end chamber 105, the second end chamber 112 and the third end chamber 110. It can be seen that the bottom of the third end chamber 110 is even or level with the bottom of the fourth end chamber 108. The bottom of the first end chamber 105 has a greater radius than a bottom of the second end chamber 112. The bottom of the second end chamber 112 has a greater radius than the bottom of the third end chamber 110. The secondary coil 73 will have coil turns in the end chambers 88 in a spiral configuration on the spiral land so as to increase progressively in diameter toward the central chambers 86. The secondary coil 73 will have coil turns in which successive turns in each of the chambers 105, 112 and 110 are axially and radially spaced from one another so as to prevent arcing.

(23) In order to achieve optimum advantage of the increased turns spacing provided by the spiral land configuration, the rate of increase in the radius of the progressive turns varies. For example, where the spiral land would have four turns, the space between the largest turn and the next largest turn is designed as to be twice as great as the space between the smallest turn and the next adjacent turn. This is because the voltage drop from one coil to the next (and thus the potential for arcing) is greatest in the first end turn of the coil and diminishes progressively for the first three or four turns. The desired relationship between the radii of adjacent turns of the spiral land will depend on many factors such as space availability, size of the winding form, design parameters of the particular ignition system, etc. In particular, the greater volume offered by the end chamber 88 further spaces the secondary coil 73 so as to further reduce the potential for arcing.

(24) 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.