Emission control

摘要

Hydrocarbon traps used to trap then release unburned hydrocarbons upon startup of a spark ignition internal combustion engine are sensitive to degradation if exposed to normal temperature exhaust gases. On board diagnostics of HC traps are provided by the invention, by incorporating a heat sensitive oxygen storage material in the HC trap material, and using conventional determination of OSC efficiency to determine if the HC trap material has been exposed to excessive temperature.