Effect of Clearance on Work

The effect of the clearance volume on work of compression is basically because of the different values of the exponents of the compression & expansion processes. If the exponents are of different, the total work is given by

While the two exponents are equivalent, i.e. m= n

Here V_s= V₁-V₄ volume of the vapour sucked. Therefore the work is just proportional to the suction volume. The clearance gas only acts as a spring, alternately expanding & contracting. However, in practice a large clearance volume results in a low volumetric efficiency and therefore large cylinder dimensions, enlarged contact area among the piston & cylinder and so, enhanced friction and work.