a De part ment of Au to mo bile En gi neer ing, Dr. Mahalingam Col lege of En gi neer ing and Tech nol ogy, Pollachi, In dia b De part ment of Me chan i cal En gi neer ing, Dr. Mahalingam Col lege of En gi neer ing and Tech nol ogy, Pollachi, In dia c De part ment of Me chan i cal En gi neer ing, Annamalai Uni ver sity, Chidambaram, In dia d De part ment of Me chan i cal En gi neer ing, Gov ern ment Poly tech nic Col lege, Coimbatore, India Orig i nal sci en tific pa per

The biooil is thermally cracked under catalytic environment in a catalytic cracking process. This process is able to replace the transesterification process to match the biofuel properties with diesel. In this study the silicon dioxide and cerium oxide were chosen as catalyst for cracking the jatropha vegetable oil. The catalytically cracked jatropha biofuel gas is delivered at constant rate to the inlet manifold of the diesel engine. Before and after cracking, the characteristics of the catalysts were analyzed using scanning electron microscope and X-ray diffraction. The condensed cracked jatropha biofuel properties were analyzed with the results of Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry analysis, and it matches with the diesel fuel. From the experimental results, the increase in brake thermal efficiency of the engine with higher oxides of nitrogen emission was observed compared with diesel for both the catalytically cracked jatropha biofuels. Notably, SiO 2 as catalyst showed the better mixing towards homogeneity with higher performance and emission results than the CeO 2 as catalyst.