PCCI combustion with RME and bio-ethanol in a transparent Euro5 diesel engine

This paper reports experiments conducted on a single cylinder direct-injection compression ignition engine operating in premixed charge compression ignition (PCCI) combustion mode. The engine was fuelled with pure Rapeseed Methyl Ester (RME) and bio-ethanol. RME was injected in the combustion chamber by CR injection system at 800 bar and bio-ethanol in the intake manifold by commercial port fuel injection system at 3.5 bar. The choice of two biofuel and the effects of different percentage of bio-ethanol were studied by means of a simultaneous in-cylinder heat release study and high-speed visualization of UV-visible chemilumi-nescence. The pollutants formation and exhaust emissions of the engine operating in dual fuel mode were evaluated. The increase of the bio-ethanol content improved the brake thermal efficiency slightly even if the brake fuel consumption increased. Nevertheless, it was compensate from the choice of two biofuel that contributed further to decrease the smoke opacity, NOX concentration and the brake specific particulate emissions.