Comparative Optical and Thermodynamic Investigations of High Frequency Corona- and Spark-Ignition on a CV Natural Gas Research Engine Operated with Charge Dilution by Exhaust Gas Recirculation

Abstract

Investigations are presented comparing the conventional spark ignition system with a high frequency corona ignition system at a single cylinder heavy duty truck type engine with optical access to the combustion chamber through a large piston window. The focus of the thermodynamic as well as the optical studies lies on the evaluation of the ignition system with regard to an increase of the maximum EGR Rate as well as on a reduction of cyclical variations. Further considerations are the influence of specific parameters of the corona ignition system, such as ignition duration and ignition voltage on the initial flame kernel formation. For the underlying combustion concept, the corona ignition system was found to offer a high potential for a significant increase of the EGR compatibility.