Abstract: A core assembly for an ignition coil in an internal combustion engine generally includes an inner core comprising an I-shaped lamination and an outer core comprising a pair of opposing C-shaped lamination stacks. A joint is formed by an end of the I-shaped lamination stack and a pair of adjacent ends of the pair of C-shaped lamination stacks. The core assembly is designed in a manner which minimizes the waste material that is scrapped when forming the lamination stacks, as well as allows the inner lamination stack to be slid down along the inner periphery of the outer stack.

Abstract: An ignition coil for an internal combustion engine minimizes the propagation of cracks in the encapsulate material surrounding the components of the ignition coil and provides a supplemental dielectric barrier. In one embodiment, the ignition coil comprises a housing, an outer core, an inner coil, and a coil assembly. The housing includes a bottom wall connected to an outer wall extending around the periphery of the housing. The outer core is positioned inside the outer wall, while the inner core is positioned inside the outer core. The coil assembly includes a primary winding and a secondary winding concentrically positioned relative to each other. The coil assembly is mounted to the inner core and positioned inside the outer core. The housing further includes an inner wall extending along the inner periphery of the outer core and positioned between the outer core and the coil assembly to prevent propagation of cracks.

Abstract: A circuit for controlling an ignition coil that attenuates the feed forward voltage by slowing the initial turn-on of the coil driver is disclosed. The turn-on circuit includes a control signal input node, a capacitor, a resistor, a diode, and a coil driver. The control signal input node receives a coil control signal from an ignition control system. The capacitor begins charging as the control signal is received by the turn-on circuit. As the capacitor charges it gradually increases the voltage provided to the coil driver. The rate of the increase in voltage is controlled by the selection of the resistor and capacitor. The slowing of the initial turn-on of the coil driver has the effect of attenuating the feed forward voltage. The attenuating of the feed forward voltage minimizes degradation of the spark gap while allowing the elimination of the high voltage zener diode.