Reduction of GHGs Emissions in a Biodiesel Fueled Diesel Engine Using Hydrogen

The experimental tests were conducted on a 7.4 kW rated diesel engine fueled with biodiesel-diesel blend (B20) for quantitative evaluation of greenhouse gases (GHGs) emissions. The result indicates that carbon dioxide (CO₂) emission did not change significantly with B20 whereas methane (CH₄) and nitrous oxide (N₂O) emissions with B20 decreased marginally as compared to base diesel. In order to reduce further these emissions, the effect of hydrogen (H₂: 20% energy share) on GHGs emissions in the biodiesel (B20) fueled diesel engine under dual fuel mode is assessed. CO₂ emission decreased drastically with H₂ due to higher thermal efficiency and lesser carbon content of the fuels than base diesel and B20 whereas CH₄ and N₂O emissions decreased significantly due to high temperature combustion. At rated load, CO₂, CH₄ and N₂O emissions of the engine decreased about 46%, 22% and 27% respectively with biodiesel (B20)-H₂ (20% energy share) under dual fuel mode as compared to conventional base B20 mode. A conclusion is clearly emerged from this study that the formation of CH₄ and N₂O emissions are dependent on in-cylinder pressure and temperature. Hydrogen addition to the diesel engine is an effective solution to reduce CO₂ along with CH₄ and N₂O emissions.