evaluating a conversion capability of the catalytic converter volume on the basis of a value which is a function of the first difference, {HEAD ~ the value} being normalized to {TAIL ~ a value} which is a function of the second difference 
normalized to
evaluating a conversion capability of the catalytic converter volume on the basis of a value which is a function of the first difference , { HEAD ~ the value } being normalized to { TAIL ~ a value } which is a function of the second difference
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 HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH