US Patent 7208078 Diesel fuel formulation for reduced emissions

The invention is directed to a method and formula for producing a fuel having reduced particulate emissions from an internal combustion engine. The fuel taught herein is characterized as having a cetane number ranging from about 45 to about 65, a T95 distillation property of less than about 370° C., and having NR, AR, cetane number and T95 defined by the relation:PEI=156+Z1×(cetane#−49)+Z2×(NR−14)+Z3×(AR−25)+Z4×(T95−315° C.)WhereZ1 ranges from abut 0.67 to about 1.06,Z2 ranges from about 0.9 to about 1.28,Z3 ranges from about 2.54 to about 2.80,Z4 ranges from about 0.1 to about 0.4,NR is a defined correlation of the naphthene rings content in the fuel, andAR is a defined correlation of the aromatic rings content in the fuel.