This mechanical efficiency is smaller than thermal efficiency because the thermal efficiency from the combustion chamber is fractionated within the linking mechanism (piston to connecting rod and connecting rod to crankshaft) after the combustion chamber stage in order to achieve power at power output shaft and this loss of power within the linking mechanism is the sole purpose/field of discussion in this efficiency calculation. As we all know “Gas pressure exerts its pressure perpendicular to the exposed area which is available as a form of force on the linking mechanism.” This postulate held that the efficiency of any internal combustion engine is fully dependent on how efficiently the linking mechanism can convert the thermal efficiency to mechanical efficiency and subsequently deliver it to power output shaft. So the sole purpose of any combustion engine is to keep the fractionation of force applied to the linking mechanism is as low as possible. This fractionation of force can be defined as to fractioning a force into a sine component and a cosine component if the force is applied on an inclined plane. The traditional reciprocating engine along with the Wankel engine having the linking mechanism which is continuously prone to higher degree of force fractionation. So considering the loss criteria described above the efficiency calculation is compiled in view of trigonometry and thermodynamic equation and can be found in the attachment below. In this calculation 30% fuel efficiency is achieved @ 8.36 compression ratio and by this method any practical efficiency can be achieved at a given compression ratio.