Performance and emission analysis on the effect of exhaust gas recirculation in a tractor diesel engine using pine oil and soapnut oil methyl ester

Abstract

Abstract The combustion of biofuel in compression ignition engines produces lower carbon monoxide and unburnt hydrocarbon emissions compared to diesel fuel but higher NOx emissions. In view of reducing NOx emission, the exhaust gas recirculation (EGR) technique was used in the present investigation to study its effect on engine performance and emission characteristics of a twin cylinder off-road vehicle diesel engine (Simpson S217-tractor). The blends of pine oil - soapnut oil methyl ester (P75SNB25), diesel - soapnut oil methyl ester (SNB20) were prepared on volume basis and used in the test engine with a fixed rate of 10% EGR under various loads. The soapnut oil was extracted from the soapnut seeds and trans-esterified in two stages using methanol and catalysts. The high viscosity of soapnut oil methyl ester is compensated by blending it with low viscous pine oil. The experiments were conducted in a four stroke, twin cylinder tractor diesel engine to study the performance and emission characteristics of the prepared biofuel blends. The results showed that the specific fuel consumption, exhaust gas temperature and HC emission of the hybrid biofuel blend P75SNB25 with 10% EGR rate decreased by 3.44%, 3.90% and 20% respectively than diesel operation without EGR at full load condition. The increase in brake thermal efficiency and CO emission of about 4.44% and 8% was also observed. For the blend SNB20 with 10% EGR, the reduction in HC, NOx emission and EGT was about 20%, 10.55% and 3.12% respectively at full load than diesel operation without EGR.