In early stages, a few towns used acetylene for lighting, including Tata in Hungary where it was installed on 24th July 1897 & North Petherton in England in 1898. Now a days acetylene is used for carburization of steel acetylene lamp, fore cavers and mines, for gas welding and cutting, etc. Acetylene gas is also called as Ethyne and Ethine, was discovered in 1836 by Edmund Davy in England, who identified it as a " New carburet of hydrogen" French Chemist Marcellin Berthelot, who coined the name "Acetylene", rediscovered it in 1860. Now a day, the fuels used for S. I. engine are petrol, kerosene, C.N.G. and L.P.G., etc., which is likely to get exhausted in future and also the cost of the fuel is increasing day by day. It creates pollution; hence it is need of time to investigate an alternate fuel, which is suitable for S.I. engine. The alternative fuel should be easily available in market at low cost. Acetylene due to its good physical, chemical and thermodynamic properties would be used as an alternative fuel. Acetylene (C2H2) is not an air gas, but a synthesis gas; generally produce from the reaction of calcium carbide with water. It is colorless gas, has a strong garlic odor, unstable, unsaturated, and highly combustible and produces a very hot flame (over 3000 o C). Acetylene can solve all the problems like combustion, knocking. Thermal efficiency, and pollution. It is available at low cost (i.e. 1 kg of carbide gives 349 lit. of acetylene which is about only Rs. 30/- approx) Acetylene is used to run S.I. engine. The power generated by engine is utilized for running machines, pumps, vehicles, SPM, etc… For experimentation purpose petrol start generator is used. The required gas kit is used as it is, used in existing system. Materials of engine parts are selected based on the properties of acetylene gas. A synthetic lubricant is used in our model, since acetylene reacts with hydrocarbon and fluorocarbon based lubricants, which are used in present system. Calcium carbide and water is placed inside a hopper of acetylene gas generator. The reaction takes place and a acetylene gas is generated the gas is then passed to combustion chamber of S.I. engine cylinder through dryer and gas kit, and it develops the power. The power generated is used to drive any type of device. Hence, acetylene gas would be used as an alternative fuel as it is easily available at low cost, ecofriendly and no major changes in the present is required. Hence acetylene gas would be a good alternative fuel for S.I. engine in future.