Effects of Ageing Cycles on Lead Tolerant Catalyst Durability

One of the central points of debate in the discussion of whether oxidation catalysts are capable of working with leaded-fuel is the simulation of in-use mileage accumulation. Various catalyst ageing cycles have been proposed. Some engine cycles have been shown to only slightly deactivate catalysts, while road ageing experience typically produces significant catalyst deactivation.

This paper will report the influence of three different engine ageing cycles on oxidation catalyst durability when a typical 0.15 g Pb/liter European fuel is used. Steady-state ageing at either 370°C or 590°C inlet temperatures were compared to a multi-mode cycle with a maximum catalyst inlet temperature of 760°C. The multi-mode cycle was developed as a simulation of the CCMC cycle requirements based on information obtained from characterizing a vehicle driven according to the recommendations of the CCMC.