Pentanol and diethyl ether have garnered considerable attention in recent years due to their ability to reduce engine emissions and over reliance on fossil fuels. A detailed diethyl-ether mechanism was reduced to 52 species and 242 reactions and incorporated into the reduced mechanism of diesel-n-pentanol. A compactoxidation mechanism of diesel-n-pentanol-diethyl-ether which composed of 193 species and 822 reactions was built. The reduction of diethyl ether was accomplished utilizing a combination of directed relation graph with error propagation and sensitivity analysis (DRGEPSA) and computational singular perturbation (CSP) approaches. The rate constants of the reactions in the fuel-related sub mechanism are optimized in order to replicate the ignition delay times seen in shock tubes and rapid compression machines. Additionally, the 3Dengine simulation was performed using KIVA-3V2-CANTERA in conjunction with the mechanism to mimic the in-cylinder pressure and rate of heat release. The results demonstrate that the simplified mechanism is capable of accurately predicting the combustion characteristics of a diesel engine running on diesel-n-pentanol-diethylether additive.