Abstract:In an electroncontrolled port injection gasoline engine, separately with gasoline, B10 and B30 at -7℃ ambient temperature, the coldstart emission characteristics of regulated and nonregulated pollutants were investigated after catalytic converter. Using chemical kinetic scheme, the main pathways of nonregulated pollutants were identified. The results show that in the first 120 seconds of cold start, with the increasing of butanol proportion, HC and CO emissions decrease for three kinds of fuel. HC and CO emissions firstly increase with latter decreasing for each kind of fuel. For the nonregulated pollutants,with the butanol volume ratio increasing from 10% to 30%, the emission volume fractions of ethylene, formaldehyde and acetaldhyde are increased by 37.0%, 67.6% and 69.9%, respectively. The addition of butanol causes 40.5% reduction in benzene emission and 16.0% decreasing in methane emission with slight effect on acetylene emission.