Recently, environmental concern and demand for a catalyst’s high performance have increased and many research activities focused on the operation of a three-way catalyst (TWC) at the end of its lifetime. Catalyst aging is the loss of catalytic activity over time that has crucial importance in emission of three-way catalyst.
 The aim of this paper is, investigating experimentally the performance of a fresh and aged three-way catalytic converter (TWC) in legislative driving cycle. For this, vehicle emission test with fresh and aged catalyst was carried out.
In this study a commercial catalyst was used, and was aged in a motor-rig, with SBC cycle (Standard Bench Cycle). The total conversions of HC, CO and NOx were decreased over the lean-rich cycles in transient conditions. In the real driving condition, almost in the all-time, the engine has transient condition and in this condition, the non-aged catalyst, achieves higher conversion for times with lambda variations.