Diesel combustion characteristics of waste vegetable oil methyl ester with 1-butanol

In order to improve the fuel properties and diesel exhaust emissions of waste vegetable oil methyl ester (WME), the blend fuels (BWME) of WME with 1-butanol are tested using a DI diesel engine. The 1-butanol content in BWME is 5 to 20 mass%. The pour point of BWME with 10 mass% 1butanol is -12.5 °C and the same as that of JIS No. 2 gas oil. There is no problem in the startability and stability of the engine operation with BWME. Thermal efficiency of BWME is almost the same as that of the gas oil. Although BWME has longer ignition delay compared with gas oil and WME due to the low cetane number of 1-butanol, the combustion end timing of BWME is same. The smoke emissions decrease with increasing 1-butanol content although the HC and CO emissions of BWME increase due to the longer ignition delay. From the experimental results, it is concluded that BWME is an alternative diesel fuel and is better than WME because of the lower pour point and the lower smoke emissions.