Engine roughness and exhaust emissions of a diesel engine fueled with three biofuels

Biofuel production is seen in many countries around the world as an alternative fuel with less carbon footprint and GHG emission compared to the fossil fuels. Biofuel methyl ester is produced using transesterification process, a blend of triglycerides and alcohol that is made for running automotive engine. As the demand on biodiesel increased, more research studies needs to be done on the current diesel engine for replacing the diesel fuel by the biodiesel. Engine performance, emission, roughness are the major concerns for the automotive industry. An experimental combustion test was conducted on a Ricardo E6 single cylinder variable compression indirect injection engine, for three different liquid biofuels compared to baseline diesel fuel. The biofuels are Jojoba Methyl Ester (JME), Algae Methyl Ester (AME), and Chocolate Waste Methyl Ester (CME). Two main sets of experiments were conducted; in the first experiment, the engine load was varied from 0.5 to 15 Nm at a fixed speed, injection timing and compression ratio, while in the second fuel injection timing is varied from 20° before top dead center (BTDC) to 45° BTDC, at constant speed, load and compression ratio. The emission levels of CO, CO₂, NO_x, SO_x and unburned hydrocarbons were measured, and the engine roughness, measured in (dP/dθ)_max. JME showed an increase in pollution levels while AME decreased significantly the pollution levels.