The pilot-fuel auto-ignition and combustion in compressed methane/air mixtures are
investigated. Experiments were performed in an optically accessible rapid compression-
expansion machine featuring quiescent charge conditions and a single-hole coaxial diesel
injector mounted on the cylinder periphery. It enabled thermodynamic analysis of the pilot-
fuel combustion without these phenomena being masked by the rapid premixed-flame
propagation like in the engine test rigs with turbulent charge. The aim of this study is to …

The pilot-fuel auto-ignition and combustion under engine-like conditions in compressed
methane/air mixtures are investigated in a RCEM using a single-hole coaxial injector. In Part
1, the phenomenology of the pilot-fuel combustion was studied based on the thermodynamic
analysis. With the addition of methane, a prolonged pilot-fuel combustion duration was
observed, especially at increased EGR rates. The aim of Part 2 is to improve the
understanding of the underlying processes governing the pilot-fuel burning and premixed …