Railplug Ignition Operating Characteristics and Performance:A Review

The basic process of spark ignition in engines has changed little over the more than 100 years since its first application. The rapid evolution of several advanced engine concepts and the refinement of existing engine designs, especially applications of power boost technology, have led to a renewed interest in advanced spark ignition concepts. The increasingly large rates of in-cylinder dilution via EGR and ultra-lean operation, combined with increases in boost pressures are placing new demands on spark ignition systems. The challenge is to achieve strong and consistent ignition of the in-cylinder mixture in every cycle, to meet performance and emissions goals while maintaining or improving the durability of ignitor.

The application of railplug ignition to some of these engine systems is seen as a potential alternative to conventional spark ignition systems that may lead to improved ignition performance. The railplug ignitor was invented and first investigated at the University of Texas at Austin in the early 1990s. This paper provides a review of the development of this ignition concept and an overview of recent developments. The paper examines the evolution of railplug geometries and designs, and operating parameters. The emphasis is on the characteristics of railplug discharge and effects on engine operation and performance.