Investigation of Internal Thermal Impact Effect on Motorcycle Catalytic Converter Activity and Microstructure

Chinese new legislations on two wheels and mopeds have been published recently. Depending on the latest exhaust statistic analyses, with the resulting of tighter limits, the application of catalytic converters is becoming a prevalent and a cost-efficient solution for Chinese motorcycle manufacturers.

The phenomenon of exhaust temperature changes rapidly during real driving process is well known as one of major destructive factors which have effects upon converter's durability.

One 125 cm³ motorcycle is selected as a typical model in this research project. Exhaust temperature of the 125 cm³ motorcycle is measured and recorded during the process of ECE 40 driving cycle. A simulation test system has been set up successfully depending on those temperature data. Conversion ratio of converter sample lost distinctly after 18 hours' thermal impact tests.

After further analyses, there were not evident changes in microstructure and substance on the surface of converter. But the O₂ store capacity reduced obviously and it was believed as the reason for conversion ratio loss by far.