Patent ID: 7178513
Filing Date: 2007-02-20
Classification: F02D,F02P,H01F,H01T

Abstract:
1. An inductive ignition system for an internal combustion engine operating at a voltage Vc substantially above the standard 12 volt automotive battery with one or more ignition coils Ti and associated power switches Swi, where i=1, 2, . . . n, with each coil having a primary winding of turns Np and inductance Lp, and a secondary high voltage winding for producing high voltage sparks of turns Ns and inductance Ls, the primary and secondary winding defining a turns ratio Nt equal to Ns/Np, the coils being of low inductance with one or more large air gaps within their magnetic core, and producing spark of peak current Is above 200 ma, the system further including means for providing the higher voltage Vc and controlling the charging and spark discharging of the ignition coils from said voltage Vc in a controlled sequential manner, and further including connection means for connecting the coil Ti secondary high voltage end to a sparking means which substantially reduces EMI following spark breakdown, the system further including electronic control means for receiving signals to fire the sparking means in their proper order, wherein a) each of the coils having an open-E type magnetic core with the open end located at the high voltage end and not having open ends at the other end of the core as in the case of pencil coils, and wherein two biasing magnets are placed in the open end of the core substantially filling the parallel two open ends or air-gaps, and having relatively higher inductance Lp than the pencil coils with two series gaps, and thus having fewer number of primary turns and satisfying the other features of the invention, i.e. biasing magnetic flux of up to 2 Tesla by use of high flux density biasing magnets; b) the biasing magnets of each such coil have a length lm essentially filling the air-gap lw or w, the winding window, and cross-sectional area ½·Abias at right angles to the air-gap direction of the bias magnetic field Bbias, and the direction of the bias magnetic field Bbias is perpendicular to the direction of the magnetic core Bcore of the area ½·Acore at the intersection of the core and the bias magnets, and the ends of the center leg and the two side legs of the core which contain the biasing magnets form core leg E-sections which are of essentially uniform cross-section, c) the biasing magets have a cross-sectional area ½·Abias with one side of the two legs of thickness “t” essentially equal to the width or thickness of the core and another side along the length “z” of dimension h approximately equal to or larger than the other dimension of the side leg, i.e. ½·Abias=t·h, whereby the dimension h is free to be chosen such that the area Abias can be greater than the total core cross-section Acore such that: (1) the bias magnetic flux density in the entire core can be as high as 2 Tesla with only one pair of bias magnets at one end versus 0.5 Tesla, and (2) the bias magnetic flux density in the entire core can be as high as 2 Tesla with only one pair of bias magnet at one end versus 1.5 Tesla with two magnets at both ends, d) the E-core is not a pencil type core but is a solid rectangular core including the biasing magnets at the open end, excluding the winding windows in which the primary winding and secondary winding are contained, e) and said open-E core with two biasing magnets located at the end of the core substantially resembles a closed E-core commonly found in automotive ignition coils, and whereby there is a reduction of the magnetic core area by approximately 40% for the same coil stored energy, to produce a system that as a whole is more versatile and smaller than prior such systems for the same high coil stored energy.