Environmental sustainability is the macro-trend that is shaping the future of automotive industry. In this scenario, the continuous tightening of emission standards has led car manufacturers to further improve the efficiency of both engine and exhaust gas aftertreatment systems. However, despite an undeniable reliability of the three-way catalyst, its conversion efficiency, which strongly depends on the composition of the exhaust gases, reaches a high level only for stoichiometric mixtures. From the perspective of a further reduction of pollutant emission limits, a potential ban on scavenging and high-load enrichment is put into focus. The first one, result of intake and exhaust cam timing overlapping at low engine speed to improve low-end torque behaviour, is responsible for a lean pre-catalyst exhaust gas composition.