ATKINSON CYCLE

This cycle has two reversible adiabatics (isentropics), one isobar and one isochore. The p-v and T-s diagrams are shown in Fig. 9.5. For one kg of the working fluid, we have

Heat supplied, q_s = c_v (T₃ – T₂)

Heat rejected, q_r = c_p (T₄ – T₁)

Net work done, w_net = q_s − q_r = c_v (T₃ −T₂) − c_p (T₄ −T₁)

Thermal efficiency, 

where 

Let compression ratio, 

Explosion ratio, 

From compression process 1 − 2, we have

For constant volume heat addition process 2 − 3, we have

Figure 9.5 Atkinson cycle: (a) p-v diagram, (b) T-s diagram

From expansion process 3−4, we have

Substituting the values of T₂, T₃ and T₄, we get