The tightening of pollution and greenhouse gas regulations generated a change in the homologation procedure, i.e., a far more dynamic driving cycle and the testing of the vehicle in real driving conditions are now part of the type approval procedure. In order to cope with these new challenges, the car manufacturers must adopt new technologies such as Miller-Atkinson cycle, which lately started to grow in popularity. This being the context, our paper’s main purpose is to present the particularities of this over-expansion thermodynamic cycle, mainly underlining its effect on the internal aerodynamic of the spark ignition engine.