Enhancing compression ignition engine performance using biodiesel/diesel blends and HHO gas

Abstract The proposed experimental study aims to investigate the effect of adding HHO gas with a constant flowrate (50% of the engine capacity) on the thermal efficiency for six different Biodiesel/diesel blends, which are 0B, 10B, 15%B, 20B, 25B and 30B. For all the studied fuelling scenarios, it was decided to mix HHO gas with the inlet air perpendicularly on the air streamline by a constant flowrate aiming to enhance the thermal efficiency of the engine. The study assumed maintain the rotational speed of the engine is constant (four different speeds) while varying the engine torque. The experimental results were recorded for four different rotational speeds of the engine, which are 1500, 1750, 2000 and 2250 RPM. Obtained results investigated that, increasing biodiesel content resulted in reducing the engine's brake thermal efficiency and increasing its brake specific fuel consumption due to the relatively lower heat content of the biodiesel comparing with conventional diesel. Adding HHO gas to the engine resulted in enhancing the thermal efficiency due to its high heat content and it was observed that; 20B with HHO gas supply provided the highest brake thermal efficiency of the engine as well as reducing its brake specific fuel consumption.