System for controlling ignition energy of an internal combustion engine

Abstract

A system for controlling ignition energy of an internal combustion engine includes an ignition coil having a primary coil and a secondary coil coupled to first and second electrodes of an ignition plug defining a spark gap therebetween, wherein the primary coil is operable to induce a spark voltage across the secondary coil and across the spark gap. The secondary coil is responsive to the spark voltage to produce a discharge current across the spark gap of the ignition plug. In accordance with one aspect of the invention, means are provided for controllably shunting the primary coil to thereby control the duration of discharge current across the spark gap of the ignition plug. In accordance with another aspect of the present invention, means are further provided for drawing discharge current away from the ignition plug to thereby limit the magnitude of the discharge current within some time period after the transfer of energy from the primary coil to the secondary coil begins. The principles of the present invention are accordingly applicable to control the duration and/or magnitude of ignition plug discharge current to thereby minimize electrode erosion while maximizing ignitability in either a conventional ignition plug-based ignition system or an arc propelling ignition plug-based ignition system.