In this paper, the combustion, performance and emission characteristics of a single cylinder diesel engine was investigated using two combustion chamber geometries such as toroidal combustion chamber and standard piston combustion chamber in a 5.2 kW single cylinder diesel engine. The experiments were carried out at an ambient temperature of 30 ± 2 °C. The performance was observed at no load 20, 40, 60, and 80%, and full load operating conditions. The results showed that the GOME 25 operated with toroidal combustion chamber has improved combustion, performance, and emission characteristics when compared to standard piston combustion chamber. The GOME 25 has improved brake thermal efficiency by about 23, 13.6, 10.6, 9.9, and 10.9% when compared to standard piston combustion chamber operated with diesel at no load, 20, 40, 60, 80, and 100% loading conditions, respectively. The smoke density and CO were reduced by about 14.8% and 38%, respectively. The NO x emission operated with GOME 25 using toroidal combustion chamber was increased by about 36% when compared to standard piston combustion chamber with diesel. The heat release rate of GOME 25 with toroidal combustion chamber was observed to be better when compared to diesel with standard piston combustion chamber. The results confirmed that toroidal combustion chamber piston is a good option for the use of GOME 25 blend.

No abstract

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.