A desulphurization event includes operating one or more emission control devices at an elevated temperature and with a selected air fuel ratio to reduce contamination, such as {HEAD ~ sulphur} and {TAIL ~ other contaminants} 
A desulphurization event includes operating one or more emission control devices at an elevated temperature and with a selected air fuel ratio to reduce contamination , such as { HEAD ~ sulphur } and { TAIL ~ other contaminants }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL