Effect of infiltration of bio-lubricant on the performance of a compression ignition engine fuelled with biodiesel blends

Lubrication is one of the most essential requirements for proper working of internal combustion engines, and mineral lubricants are extensively used for that. However, their disposal causes environmental degradation. A logical solution for this may be achieved by using bio-degradable and environmentally acceptable lubricants. A few recent researches have focused on utilizing biofuels, which are primarily used as alternative engine fuels, as lubricants to address environmentally related issues with mineral lubricant. In this context, straight vegetable oils seem to be a promising option. The available literature suggests that 20 % biodiesel has superior effects on the lubricating oil properties compared to diesel when mineral oil is used as lubricant. Therefore, the study of the effect of infiltration of lubricant into the fuel side on the performance and emission characteristics on one hand and infiltration of fuel in the lubricant on the other have been considered in the present work for long-term engine operation. For that, the performance and emission characteristics of palm biodiesel blends with palm oil as lubricant were compared with those of conventional diesel fuel with mineral lubricant for 60 h operation. The variations in viscosity and density of both the lubricants for 60 h operation were also considered. Based on the comparative assessment of the considered fuel–lubricant combinations, it is concluded that the same B30 palm biodiesel fuel blend with palm straight vegetable oil as lubricant may be considered as the most suitable combination. This fuel–lubricant combination will surely reduce the dependency on fossil fuel to a large extent and earn more carbon credits.