A method for desulphating NOx traps and a method for sulphating an internal combustion engine emission control system under test conditions.

摘要

A method for desulphating a NOx trap comprises passing a reducing gas through the NOx trap while it is operating at a temperature in excess of a predetermined minimum, the duration of the desulphating event being predetermined solely upon the temperature of the NOx trap during the desulphating process. The desulphation time may be obtained from a look-up table. A method for sulphating an internal combustion engine emission control system under test conditions, comprises running the emission control system in the exhaust of an engine and injecting sulphur dioxide (SO2) as a gas immediately upstream of the emission control system. The emission control system may be a NOx trap.