Against the backdrop of growing global demands for energy sustainability and
stricter emission regulations for diesel engines, this study investigates the
performance implications of incorporating cyclohexanol—a renewable oxygenated
fuel—into diesel fuel blends. Using a marine medium-speed diesel engine as the
experimental platform, the research systematically evaluates engine performance
and emission characteristics across a range of cyclohexanol-diesel blend ratios
under low, medium, and high load conditions. Experimental findings reveal
multifaceted effects of cyclohexanol blending on engine operation. Combustion of
the blended fuels enhances the engine’s dynamic performance, particularly under
medium and high loads, where the maximum in-cylinder burst pressure exhibits a
noticeable increase. This improvement is attributed to cyclohexanol’s
oxygen-carrying capacity, which promotes more vigorous and sustained combustion
reactions. In terms of emissions, increasing the proportion of cyclohexanol in
the fuel blend leads to significant reductions in soot and carbon monoxide (CO)
emissions, reflecting the cleaner-burning properties of the oxygenated
component. However, this is accompanied by an uptick in nitrogen oxide
(NOx) emissions, likely due to the elevated combustion
temperatures generated by the more efficient fuel oxidation process. From an
economic perspective, cyclohexanol blending at consistent load levels induces a
postponement in the crank angle at which peak heat release occurs during
combustion. This temporal shift prolongs the effective combustion duration,
enabling more complete fuel utilization within the cylinder. Consequently, fuel
consumption rates decrease, and overall engine efficiency improves, highlighting
the potential of cyclohexanol blends to enhance operational economy in marine
propulsion systems. In summary, this study underscores the complex trade-offs
associated with cyclohexanol-diesel blends: while they offer tangible benefits
in power output, fuel efficiency, and reduced particulate emissions, managing
the increase in NOx emissions remains a critical challenge. The
results provide a foundational framework for advancing biofuel applications in
marine engines, emphasizing the need for integrated emission control strategies
to optimize the balance between performance and environmental
sustainability.