Patent ID: 8870983

Claim:
A method for producing a butanol gasoline blend having good cold start and warm-up (CS&W) driveability performance comprising: (a) providing at least one biologically-sourced butanol isomer; (b) blending the butanol isomer and optionally ethanol with gasoline to form a butanol gasoline blend, the butanol gasoline blend having a vapor pressure corresponding to a specific ASTM D4814 vapor pressure/distillation class of gasoline; (c) determining a value of low butanol driveability index (LBDI) for the butanol gasoline blend wherein the LBDI value is determined by the equation: a 1 T 10 +a 2 T 50 +a 3 T 90 +a 4 EtOH+BuOH (a 5 −a 6 E200); wherein: T 10 is the temperature for distillation of 10-volume percent of the butanol gasoline blend; T 50 is the temperature for distillation of 50-volume percent of the butanol gasoline blend; T 90 is the temperature for distillation of 90-volume percent of the butanol gasoline blend; EtOH is the concentration in volume percent of ethanol in the butanol gasoline blend; BuOH is the concentration in volume percent of the at least one biologically-sourced butanol isomer in the butanol gasoline blend; E200 is the volume percent of the butanol gasoline blend that distills at temperatures up to about 200° F.; and a 1 , a 2 , a 3 , a 4 , a 5 and a 6 are coefficients selected to give a substantially linear relationship between the values of the linear combination for the butanol gasoline blend containing the at least one butanol isomer and optionally ethanol and the logarithms of the mean corrected total weighted demerits from test measurements of CS&W driveability performance for such blends, at concentrations of ethanol less than about 20 volume percent, at concentrations of the at least one biologically-sourced butanol isomer less than about 30 volume percent, and at total concentrations of ethanol and the at least one biologically-sourced butanol isomer less than about 35 volume percent; and wherein the total weighted demerits of the butanol gasoline blend is less than about 40; and (d) optionally adjusting the amount of gasoline, the butanol isomer, and the ethanol, or any combination thereof, such that the value of LBDI is below the maximum limit for Driveability Index (DI) for the specific class of gasoline as specified in Table 1 of ASTM D 4814.