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The increasing population and the vehicle strength are alarming that arises the importance of the issue to deal with alternative fuels in existing diesel engine without modification The biodiesel is derived from vegetable oils to replace the conventional diesel fuel. In this research, we have considered the esterified rice bran oil as biodiesel. Even though it is edible oil, the consumption of rice, particularly in south India, is more when compared with the other parts of the world that enables the preparation of the fuel quickly. The rice bran oil prepared by the trans-esterification method and tested in a VCR engine in blends of 10% and 20% with pure diesel. The engine compression ratios were chosen as 16:1, 17:1 and 18:1. This research includes investigation on performance, combustion and emission by varying the compression ratios for the blends and compared with pure diesel and conducted experiments with a turbocharger, fitted with the engine. The results obtained were presented and analysed to optimise the suitable blend and compression ratio. [ABSTRACT FROM AUTHOR]

Biodiesel is considered an immediate substitute for the fossil diesel as the fuel properties, such as calorific value, density, ash content and acid value are comparable to the diesel. In India, pongamia oil has considerable potential for the biodiesel production. The pongamia oil biodiesel has lower volatility and slightly higher viscosity than the diesel. Hence the pongamia oil biodiesel fuelled diesel engine results in lower thermal efficiency as compared to the diesel. The carbon nanotubes (CNTs) were used in this work as additive to the pongamia oil biodiesel, to enhance the atomization and to reduce the ignition delay of the pongamia oil biodiesel. The CNTs were added to the pongamia oil biodiesel with different dosages and subjected to ultrasonication for 60 min, to prepare homogenous mixture. The engine tests were conducted on a single cylinder diesel engine without making any modifications in the fuel injection system. The addition of CNTs to the pongamia oil biodiesel resulted in higher brake thermal efficiency at higher loads between 75 to 100 % of the full load. From the engine tests, it was observed that the CNTs improves the engine thermal efficiency and reduces the CO, HC and smoke emissions of the diesel engine depends upon the CNT dosage. This is due to shorten ignition delay caused by the CNTs which improves the combustion of the pongamia oil biodiesel. The optimum CNT dosage of 50 mg/l results in 4% increase in thermal efficiency and reduces the CO, HC and smoke emissions by 20.33, 25 and 12.5% respectively at full load. [ABSTRACT FROM AUTHOR]

Currently, India imports 84% of its total oil needs and aims to bring that down to 67% by 2022. To aim for this, the hunt for sustainable production of non-toxic, renewable, and low-cost alternative fuel sources is the need of the hour. Azolla microphylla plant which grows on the water surfaces can be a potential feedstock for the production of biodiesel. The oil was extracted from the azolla plant by the solvent extraction method. The biodiesel was produced from the azolla oil through the transesterification process. The azolla biodiesel was blended with the diesel in the ratio of 25:75, 50:50, and 75:25 by volume and tested in a diesel engine at the part and maximum load conditions. The engine characteristics of the azolla biodiesel blends, neat azolla biodiesel, and sole diesel were compared. The result showed that brake thermal efficiency (BTE) was highest for the B25 (25% azolla biodiesel, 75% diesel) blend with a value of 25.9% which was less than sole diesel, whose BTE value was 26.8% at maximum load. The high viscous nature of biodiesel blends results in inferior evaporation and improper air–fuel mixing process. Due to this, the B25 blend gave the least CO, HC, and smoke emissions among the test blends, but slightly higher than that of neat diesel. The NO emission for diesel was 852 ppm, 882 ppm, and it is 806 ppm, 824 ppm for B25 at the part and maximum load respectively. The peak cylinder pressure for diesel and B25 blend was 50.8 bar and 49.4 bar respectively at maximum load. [ABSTRACT FROM AUTHOR]