One of the most difficult challenges in engine technology today is the urgent need to increase engine thermal efficiency. Higher efficiencies mean less fuel consumption and lower atmospheric emissions per unit of work produced by the engine. In 1862 a Frenchman Alphouse Beau de Rochas gives his theory regarding the ideal cycle of the internal combustion engine. This theory is applied by a German engineer named Nikolaus A. Otto, who firstly built a successful four-stroke SI engine in 1876. The four-stroke combustion cycle later became known as the "Otto cycle". In four stroke engine, the piston executes four complete strokes within the cylinder, and the crankshaft completes two revolutions for each thermodynamic cycle. The disadvantage of the four-stroke cycle is that only half as many power strokes are 2 completed per revolution of the crankshaft. The capacity of the four strokes would be 340cc only. Less torque is generated during the process. Pollution is more in four stroke engine. In six strokes the engine captures the exhausted heat from the four stroke cycle and uses it to get an additional power and exhaust stroke of the piston in the same cylinder. This heat is used to generate the steam from the water which is further used as a working fluid for the additional power stroke. This steam will forces the piston down. As well as extracting power, the additional stroke cools the engine by water and removes the need for a cooling system making the engine lighter and giving 40% increased efficiency over the normal Otto cycle. The pistons in this six stroke engine go up and down six times for each injection of fuel. These six stroke engines have 2 power strokes: one by fuel, one by steam.