Treatment system for gasoline compression ignition engine exhaust

A method of making a system for treating gasoline compression ignition engine exhaust, comprising:

• aligning into the system a plurality of components comprising:
• a carbon monoxide absorber and a nitrogen oxide absorber, wherein nitrogen oxide comprises one or more compounds consisting of nitrogen and oxygen;
• an oxidation catalyst downstream of the carbon monoxide absorber, wherein the nitrogen oxide absorber is disposed over the oxidation catalyst;
• a close coupled reduction catalyst downstream of the nitrogen oxide absorber;
• an electrically heated catalyst between the oxidation catalyst and the close coupled reduction catalyst;
• an underfloor reduction catalyst downstream of the close coupled reduction catalyst;
• and
• an ammonia slip catalyst downstream of the underfloor reduction catalyst;
• configuring the carbon monoxide absorber to capture and store carbon monoxide under cold start operation;
• configuring the nitrogen oxide absorber to capture and store nitrogen oxide, under cold start operation;
• and
• configuring the underfloor reduction catalyst and ammonia slip catalyst to in combination reduce slip ammonia released by the close coupled reduction catalyst under high load operation.