Comparative Study of Engine Performance and Exhaust Emission Characteristics of a 4-Stroke Compression Ignition Engine Operated with Various Blends of Biodiesel Extracted from Crude Rice Bran Oil and Rice Bran Oil

Abstract

Biodiesel is receiving increased attention as an alternative, non-toxic, biodegradable, and renewable diesel fuel. It is derived from oils and fats by transesterification with alcohols. The main hurdle to the commercialization of biodiesel is the cost of raw materials. Nonedible, inexpensive, low-grade high free fatty acid rice bran oil as raw material, continuous transesterification process and recovery and purification of bioactive compounds from biodiesel by-product are primary options to be considered to lower the cost of biodiesel. An improved engine design can lead to lesser fuel consumption along with better engine performance. This thesis is focused on biodiesel production from crude rice bran oil and rice bran oil, comparative study of engine performance and exhaust emission characteristics between the prepared biodiesel with diesel and optimization of the compression ratio of a compression ignition engine fuelled with blends of biodiesel. Firstly the methyl esters of crude rice bran oil and rice bran oil were prepared. Crude rice bran methyl ester was produced by an acid catalyzed transesterification followed by base catalyzed transesterification and rice bran methyl ester was produced by base catalyzed transesterification. In the second part experiments were carried out at different compression ratios ranging from 12 to 18 to figure out the optimum compression ratio of a compression ignition engine. A B20 blend of rice bran methyl ester was used as fuel for conducting the experiments. After that comparative analysis based on engine performance and exhaust emission results of B10, B20 and B40 blends of crude rice ban methyl ester with diesel at compression ratio 12 and 14 was investigated. In the last part comparative analysis based on engine performance and exhaust emission results of B10, B20 and B40 blends of crude rice bran methyl ester and rice bran methyl ester at compression ratio 14 was investigated. Based on the experimental investigation the blends of crude rice bran methyl ester can be used as fuel in diesel engine without making any modification to the engine.