Experimental comparison of pure hydrogen and HHO (hydroxy) enriched biodiesel (B10) fuel in a commercial diesel engine


  • Effects of H2 and HHO to performance and emissions of a diesel engine are examined.
  • Fossil fuel dependency reduced at volumetric ratio of 10% by using biodiesel.
  • Fuel pump plunger pin was re-set and diesel fuel injection has been decreased.
  • In terms of exhaust gas emissions, H2 + B10 provided better results than HHO + B10.
  • Engine performance outputs of HHO + B10 fuel was better than H2 + B10 fuel.


The main objective of this study is to compare performance and emission characteristics of a pilot injection diesel engine with the additions of alternative fuels like pure hydrogen, HHO and biodiesel. In order to achieve this goal, Helianthus annuus (sunflower) biodiesel was produced and blended with a volumetric ratio of 10% with diesel fuel. Additionally, intake air was enriched with pure hydrogen or HHO via intake manifold without any structural changes except the reduction of injected diesel fuel on the 3.6 L, four cylinders, four-stroke diesel engines. The amount of Hydrogen fuel supplied to the engine was adjusted to a constant 10 L/min during the experiments. The effects of pure hydrogen and HHO usage with the addition of biodiesel to the engine performance values (Brake Torque, Brake Power and Brake Specific Fuel Consumption) and exhaust emission values (NOx, CO2, CO) were investigated in between 1200 and 2600 rpm engine speeds. Engine performance values were increased with the enriching the intake air with HHO than pure hydrogen compared to the standard diesel fuel operating condition. On the other hand, in terms of exhaust gas emissions, pure hydrogen provided better results than HHO. In both cases, changes in the engine performance results were minimal however improvements in exhaust gas emissions were very promising.


Hydrogen, HHO (hydroxy), Biodiesel, Pilot diesel injection, Performance, Emissions

Full text: Experimental comparison of pure hydrogen and HHO (hydroxy) enriched biodiesel (B10) fuel in a commercial diesel engine


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