The Structural Properties of an Aged Catalytic Converter and Determining the Effects on Engine Characteristics

Catalytic converters are emission control systems used to reduce the pollutant emissions, primarily CO and HC, in vehicles powered by gasoline engines. The establishment of emission limitations (standards) by various organizations makes the use of these control systems mandatory. Catalytic converters are widely used in gasoline engine vehicles to control pollutant emissions. However, the effects of the operating time of these systems on their structure and engine characteristics are an important research topic. This study aims to understand the alteration in the structure of aged catalytic converter and the effect of aged catalytic converter on engine performance and emission characteristics. In this context, the structures of aged and fresh catalytic converters were characterized using SEM, XRF, XRD, and BET surface area analyses. Additionally, the aged and fresh catalytic converters were tested on the vehicle under real operating conditions, and the engine power, CO, and HC emission values were compared. As a result of the analyses performed, it was determined that significant changes occurred in the structure of the catalytic converter depending on its usage. The surface area, pore structure, and precious metal content in the catalytic converter, which are crucial for catalytic activity, decreased, while toxicity increased. The engine performance and emission tests revealed that the aged catalytic converter caused an average decrease of 4.76% in engine power compared to the fresh catalytic converter. Additionally, the CO and HC emissions increased on average from 0.04% to 0.06% and from 9.40 ppm to 25.99 ppm, respectively.