An engine combustion model was built using AVL FIRE software

and the reduced mechanism of n-heptane-methyl decanoate-methyl-9-decanoate was used as the combustion kinetics mechanism of soybean methyl ester (SME)-diesel blended fuel to study the effect of SME and diesel blended in 30∶70 and 70∶30 (in volume) on the characteristics of combustion and emissions with single injection and main-post injection. The results show that

with the increase of SME content

the peak cylinder temperature is decreased. The combustion heat release is mainly affected by the dehydrogenation reaction rate of OH radical and fuel

and the reaction rate increases with a rise in temperature. NOxemission which is mainly affected by temperature decreases with the increase of the SME-diesel ratio. With the single injection mode

the greater the SME-diesel ratio is given

the lower the soot emission is produced. With the main-post injection mode

the production of soot decreases as the SME-diesel ratio rises because of the effect of C2H2; OH plays a dominating role in the process of soot oxidation

while the SME-diesel ratio does not matter much to the emission of soot.