Experimental Investigation on the Performance and Emission Characteristics of Direct Injection Medium Duty Transport Diesel Engine Using Rice-Bran Oil Biodiesel

Over the past several years, there has been increased interest in alternative diesel fuels to control emissions and provide energy security. Biodiesel is a fuel that can be made from renewable biological sources such as vegetable oils and animal fats, has been recognized as an environment friendly alternative to mineral diesel. In present investigation, rice bran oil (non-edible) was transesterified to methyl ester and reaction conditions for transesterifcation process for rice bran oil were optimized. Various properties like viscosity, density, flash point, calorific value of the biodiesel thus prepared are characterized as per ASTM norms (ASTM D6751) and found comparable to diesel. Steady state engine dynamometer test at full throttle conditions have been carried out to evaluate the performance and emission characteristics of a medium duty transportation DI diesel engine. Engine was fuelled with various blends of rice-bran oil biodiesel (ROME) and mineral diesel ranging from 5% biodiesel to 100% biodiesel (5, 10, 20, 30, 50, and 100%). Performance and emission data were compared to the baseline data obtained using mineral diesel. Same engine without any hardware modification has been adopted for tests on all fuel blends. The results of this experimental investigation showed that biodiesel and biodiesel blends exhibited almost similar torque and power characteristics. Biodiesel blends up to 20% produced slightly higher torque and improved performance. Improvement in fuel conversion efficiency was found for lower concentration blends i.e. up to 20%. Lowest efficiency was found for 100% biodiesel blend. All the biodiesel blends emitted lower total hydrocarbon, carbon monoxide emissions and smoke opacity but slightly higher NOx emissions during the full throttle tests. Emission tests with all the fuel blends have also been carried out using European 13 MODE test (ECE R49) procedure. Drastic reduction in THC and CO and slight increase in NOx was observed.