Abstract in the present world many difficult challenges are being faced to improve the engine thermal efficiency in addition to the four stroke there are another four more strokes to improve the efficiency in this paper the eight stroke engine is explained in a theoretical way in this engine after completing four strokes ethanol is injected into the chamber so the process repeats as that of four strokes by this it will be able to complete eight strokes in the engine automobiles industry may be revolutionized for eight stroke design to increase the efficiency of the engine Keywords engine combustion heat efficiency Introduction One of the most difficult challenges is being faced by the world to improve the engine thermal efficiency The 8 stroke engine is an internal combustion engine with advanced features for more power generation In 8 stroke engine with the additional four strokes are added to the four stroke engine so by this as number strokes increase the efficiency of the engine where ethanol is used as fuel in the fifth stroke so when we inject ethanol into the cylinder the crank moves down then the ethanol injection valve closes the crank move upwards in the sixth stroke In the seventh stroke the compressed ethanol mixture is ignited with a spark plug then due to combustion the crank moves downward In the eighth stage the crank moves upwards when the burnt gases released through the exhaust value so by this engine completes 8 strokes in the cylinder In an eight stroke engine the injection of two fuels will be alternatively in sprayed into the cylinder it helps in reduction of fuels and gives more efficiency
