Stability of Diesohol using Biodiesel as Additive and its Performance and Emission Characteristics in a Compression Ignition Engine under Various Compression Ratios

摘要

An experimental investigation is carried out to establish the performance and emission characteristics of a compression ignition engine using diesel-ethanol-biodiesel blends with respect to the compression ratio. The experiments are conducted in two phases; in the first phase, the stability analysis of fuel blends by varying the proportions of diesel and ethanol is conducted. As the diesel and ethanol are immiscible to each other, the biodiesel prepared from jatropha oil through transesterification is used as a bridging agent to prevent phase separation. The study reveals that the stability of blends decreases with the decrease in the ambient temperature and the quantity of bio-diesel required to prevent the phase separation increases with the proportion of the ethanol. In the second phase, performance characteristics are studied using the stable fuel blends in a single cylinder four stroke computerised variable compression ratio engine coupled with an eddy current dynamometer and a data acquisition system. Exhaust gas analyzer is used for the investigation on exhaust gases; CO, HC and NO and smoke meter is used to measure the smoke absorption coefficient. The performance and emission characteristics of the engine using the stable diesel-ethanol-biodiesel blends are determined for the compression ratios of 15, 17 and 19. The experimental observations indicated that using desired quantity of biodiesel and ethanol with diesel and by varying the engine compression ratio, the performance and the exhaust emission could be improved significantly.