Abstract
Reducing the emission pollution related to fossil fuel combustion is gaining increasing interest worldwide and the researcher did an intensive effort to reduce the dependency on fossil fuel. This work conducted an experimental study on the effect of the hydroxyl gas (HHO) produced by water electrolysis on the spark ignition engines performance. Experimental setup and procedures are performed in internal combustion laboratory at variable speeds. Different parameters like brake power, brake specific fuel consumption, thermal efficiency and emission gasses from the exhaust, were taken under consideration. It was found that brake power increased from 1059 W to 1186 W at engine speed 2600 rpm when 3 L/min of HHO added in the intake manifold and increased from 1198.2 to 1413 when the engine speed 2400 rpm. It has been observed that a significant reduction in specific fuel consumption from 968 for pure gasoline to 792 g/kW.hr at the brake power 314 W and from 506 to 365 g/kW.hr. The thermal efficiency improved from 16.93% for pure gasoline to 23.48 % by adding 3 L/min of HHO , this improvement can be attributed as a result of wide range of flame propagation and fast flame speed of hydrogen, while carbon monoxide, hydrocarbons significantly reduced. HC reduced from 240 to 215 PPM at 2600 rpm whereas CO decreased from 3.9 to 2.7 % volume. Therefore, HHO is recommended as promising substitute fuel. Since the addition of HHO gas to the fuel increased the combustion temperature, NOx emissions were slightly increased.