Pine oil-soapnut oil methyl ester blends: A hybrid biofuel approach to completely eliminate the use of diesel in a twin cylinder off-road tractor diesel engine

Tractor engine performance using hybrid biofuel (Soapnut oil methyl ester and pine oil blends) [Display omitted] •The hybrid biofuel strategy is adopted in a tractor diesel engine to eliminate the usage of diesel.•Highly viscous soapnut oil methyl ester is blended with low viscous pine oil.•The performance, combustion and emission characteristics were tested for the blended fuels.•BTE of the blend P50SNB50 and P75SNB25 were increased at full load condition compared with diesel. Off-road vehicles used for construction and agricultural activities are one among the major source of exhaust emission. In order to reduce the environmental impact caused by these vehicles, it is encouraged to use biofuels which are renewable and locally available throughout the year. In the present work, a light biofuel- pine oil was introduced to blend with a methyl ester derived from soapnut oil. This paper details the experimental investigations of the performance, combustion and emission characteristics of an agricultural tractor engine using the combination of biofuels as a complete replacement of conventional diesel fuel. The methyl esters of soapnut oil was blended with pine oil at different proportions. The blends P100SNB0, P75SNB25, P50SNB50, P25SNB75 and P0SNB100 were prepared on volume basis and complied with ASTM D-6751 specifications. The experiments were conducted in a Simpson S217, Twin cylinder tractor diesel engine to study the performance, combustion and emission characteristics of the prepared biofuel. The results showed that the specific fuel consumption of P100SNB0 and biofuel blends decreases up to 4% with the increased engine load. The brake thermal efficiency of the blend P50SNB50 and P75SNB25 were increased by 8% and 10% respectively at full load condition compared with diesel. The biofuel blends outperformed conventional Petro-diesel in terms of smoke, unburnt hydrocarbon (HC) and carbon monoxide (CO) with a slight penalty on NOx emissions. Up to 50% pine oil blended biodiesel (P75SNB25, P50SNB50) fuel can be used in diesel engines without affecting its performance, emission and combustion characteristics.