APPLICATION OF HIGH-ENERGY IGNITION SYSTEMS TO ENGINES

Spark ignition engines are critically dependent on repeatable, reliabl e ignition to produce good performance and low pollutant emissions. Po llutant regulations and available three-way catalytic converter contro l technology determine that most engines are run with a nearly stoichi ometric mixture. For stoichiometric gasoline-air engines, current tran sistor-switched coil spark discharge systems provide adequate ignition energy and are very reliable. However, lean burning engines are desir able for their better fuel economy. New catalytic converter technology may allow development of lean burning, high compression ratio engines which meet tight emission standards while providing better fuel econo my. However, lean mixture engines (phi < 0.7) generally require much h igher ignition energy to ensure reliable ignition. Other engine develo pments requiring high energy ignition systems include natural gas engi nes and cold-starting applications of diesel and methanol fuelled engi nes. This paper reviews progress on alternative ignition systems that supply higher energy sparks and sparks where the energy is more effici ently transferred to the gas mixture. Recent developments and demonstr ations include high energy breakdown ignition systems, plasma jet igni ters, and rail igniters. In addition, progress towards distributed ign ition through prompt exhaust gas recirculation or prechamber torch,jet ignitions is covered. (C) 1997 Elsevier Science Ltd.