Development of a Long Duration Capacitive Discharge Ignition System

The development and testing of a new long secondary duration capacitor discharge ignition system is described. Results obtained on a large-bore, slow speed, 2-stroke test engine are described and compared to the results obtained by a commercially available capacitor discharge (CD) single-strike and double-strike ignition system. These tests are conducted under rated full load conditions and high boost lean operation. Engine emissions, fuel consumption, and misfire rates are analyzed and compared in order to determine if such a product merits commercialization. It has been previously demonstrated that multi-strike ignition systems (four strikes per compression stroke) can offer significant reductions in emissions and misfire rate in large-bore slow speed engines field retrofitted to increased boost lean operation for much lower costs than physical modifications to the heads to accommodate prechambers and fuel systems modifications. The work described here utilizes single and double-strike systems (two strikes per compression stroke) with lower energy than previous tests and lower total cost. The extended spark system tested is a proprietary development capacitor discharge system offering the benefits of capacitor discharge design with extremely long duration.