Impact of Fuel Properties on the Performance of a Direct Injection Diesel Engine under Part Homogeneous Operating Conditions 2011-01-1358

Tightening of emission norms necessitate intensified research in the field of emissions reduction. Fuel research opens up a vast area of potential improvement, since combustion behavior and the nature of the combustion products can be heavily influenced by fuel composition. In this paper, the effects of fuel properties on combustion and emissions shall be discussed, based on the study of standard diesel fuel, two types of diesel-like fuels and a kerosene fuel. Investigations were conducted on a single cylinder heavy duty direct-injected diesel engine operating under part-homogeneous combustion in the part-load operating range. For this purpose, a statistical design of experiments method (DOE) was utilized in order to evaluate the influence of each fuel property and, thus, develop a model for all selected fuels. Variation in EGR rates, injection and air patterns have significant effects on the combustion in the fuels under investigation. Therefore, common DOE plans with the same engine DOE parameters and ranges have been considered for all investigated fuels. On the other hand, the centroid of combustion was maintained constant for each operating point for all the fuels, to have the same evaluation basis. This investigation contains the experimental results obtained at the test cell, followed up with heat release calculations, to analyze combustion rates. Based on these investigations, the impact of the different fuels on the efficiency and raw engine emissions shall be discussed. Results show the potential of each fuel, based on its physical and chemical properties. Kerosene, with its high volatility and zero aromatic content appears desirable for application in heavy duty diesel engines. Further, part homogeneous combustion offers a possibility to reduce the amount of exhaust after-treatment.