IR analysis of dual fuel combustion in single cylinder research engine fueled with methane and diesel 2019-01-1165

In the present activity, dual fuel operation was investigated in a single cylinder research engine. Methane was injected in the intake manifold while the diesel was delivered via the standard injector directly into the engine. The aim is to study the effect of increasing methane concentration at constant injected diesel amount on start of combustion, combustion evolution and pollutant formation in an optically accessible engine. IR imaging was applied in cycle resolved mode. Several filters were adopted to recognize the spatial distribution of several species involved in the combustion process in the IR wavelength range. In particular, the detected combustion emission both in the visible and IR wavelength range was measured by the images and compared with the ROHR of the several operating conditions investigated. Ignition delay is not affected by the premixed charge of methane and the combustion duration increases with increase the charge of methane in agreement with previous work [SAE Paper 2015-24-2461]. Using the band-pass IR imaging has been possible to provide qualitative information about fuel-vapour distribution and ignition locations during low and high temperature combustion.