Single-cylinder engine evaluation of a multi-component diesel surrogate fuel at a part-load operating condition with conventional combustion

Simple, yet fully-representative surrogate fuels are needed to model market Diesel fuels. The surrogates must closely mimic market Diesel fuel properties and match the engine combustion and emissions behavior. To this end, the combustion and emissions performance of a market Diesel fuel and a four-component surrogate fuel were investigated using a single-cylinder, light-duty Diesel engine with contemporary combustion and fuel injection technology. The surrogate fuel, which was developed in previous work, was composed of normal-hexadecane/2,2,4,4,6,8,8-heptamethylnonane/decahydronaphthalene/1-methylnaphthalene with a volume fraction formulation of 0.37/0.33/0.18/0.12. Fuel test results showed the physical, chemical and combustion properties of the market Diesel fuel were closely matched by the surrogate. The fuels were evaluated by engine tests conducted at 1500 r/min and 9 bar IMEP. At this operating condition, the Diesel combustion process demonstrated low-temperature heat release, premixed and diffusion combustion regions. Test results from EGR and combustion phasing sweeps showed the engine combustion behavior, exhaust CO, HC, NOx, smoke and particle size distributions from the market Diesel fuel were very closely matched by the surrogate fuel. It can be concluded that under the engine conditions evaluated by this work, the four-component surrogate fuel accurately represents the market Diesel fuel. Thus, for conventional Diesel combustion conditions, the surrogate should prove useful for future applications such as kinetic mechanism development, fuel spray and combustion simulation, and further experimental investigations.