Chiang Mai Journal of Science

Palm oil biodiesel (POB) has a number of beneficial properties of the environment due to less exhaust emission (carbon monoxide, hydrocarbon, and smoke). It can lead to a reduction of pollution by decreasing the emission of harmful and hazardous substances to the atmosphere. In this work, palm biofuel was produced in house from crude palm oil with transesterification reaction carried out using a base catalyst. A low-speed agriculture engine under the variable load range of 3-12kg at a constant speed of 1500 rpm was investigated the several combustion characteristics under ASTM standards. The effect of a variable compression ratio (VCR) from 16 to 18 on low-speed engine performance and the gas emission were investigated in order to find out the optimal values of compression ratio (CR) low-speed engine. The experimental results are found that this engine fueled by the biofuel under test load at 12kg obtained the highest thermal efficiency of 27% at the compression ratio of 18, while its brake specific fuel consumption reduced with the increase of the test load. An increase up to CR18 presents the consistent explanation of the higher heat release and the shorter ignition delay, while the amount of carbon monoxide and hydrocarbon emission effectively reduced down to 42% and 21%, respectively. The optimum performance of the low-speed agriculture engine was found in CR value of 18 during full load condition.