Micro-Pilot and Spark Ignition Tests on the Same 5 L/Cylinder Displacement Engine

The paper compares engine performance and economics for two combustion systems which were designed, optimized and tested on the same gas engine featuring approximately 5 liter per cylinder displacement and 1500 rpm engine speed. The traditional open-chamber spark-ignited combustion system (SIOC) was in competition with the pre-chamber micro pilot (PCMP) combustion system which involved gas combustion ignited by a very low diesel fuel quantity injected into the prechamber. The paper gives an insight into the two different combustion systems by showing and comparatively analyzing measurement results. The impact of both systems on combustion specifics, turbocharging and ignition systems are discussed. Combustion and thermodynamics benefits of the PCMP system are correlated to the additional development effort and systems required as well as to engine cost. Finally a strategic conclusion is drawn on the combustion system to be chosen in view of future engine performance and emission requirements and with respect to the economics of a gas engine of this size.