Abstract: The ever increasing cost of conventional fossil fuels and their associated environmental impact have become major concerns worldwide.[1] In order to conserve the petroleum fuels for future and to eliminate the environmental problems there is need of alternative fuel. Using hydrogen or hydrogen enriched gas has proved to be one of the viable solutions for alternative fuel. . this study is carried out to investigate the effect of HHO gas addition on engine emission and it with pure gasoline fuelled engine. Here the HHO gas was produced by the process of water electrolysis and device called HHO generator has been easily integrated with SI engine test rig. The experimental work is carried out on a 250cc single cylinder petrol engine under constant speed with varying load condition. Amount of HHO gas aspirated into the combustion chamber along with intake air system at Four different amperes i.e. 1 ampere,3 ampere 5 ampere and 6 ampere with 12 volts DC supply at compression ratio 7. The result shows that the carbon monoxide (CO) has been reduced by 38.6% and hydrocarbon (HC) has been reduced by 39.7% .

Keywords: -Internal combustion engine, Petrol engine, electrolysis, Oxy hydrogen gas, Emission.