Conventional diesel-fuelled Partially Premixed Compression
Ignition (PPCI) engines have been investigated by many researchers
previously. However, the ease of ignition and difficulty of
vaporization of diesel fuel make it imperfect for PPCI
combustion.
In this study, dieseline (blending of diesel and gasoline) was
looked into as the Partially Premixed Compression Ignition fuel for
its combination of two fuel properties, ignition-delay-increasing
characteristics and higher volatility, which make it more suitable
for PPCI combustion compared to neat diesel. A series of tests were
carried out on a Euro IV light-duty common-rail diesel engine, and
different engine modes, from low speed/load to middle speed/load
were all tested, under which fuel blend ratios, EGR rates,
injection timings and quantities were varied. The emissions, fuel
consumption and combustion stability of this dieseline-fuelled PPCI
combustion were all investigated. The results showed that dieseline
had great advantages as a PPCI combustion fuel in terms of emission
reduction. This was particularly significant at high-speed engine
mode. It was also found that with a blend of 50% gasoline in
diesel, the particle numbers total concentration could be reduced
by 90% while low NOx level and high brake fuel
conversion efficiency (around 30%) were maintained at all the loads
tested.
