This paper describes engine research - which supports our program to develop a gasoline engine management system (EMS) with an on-board reformer to provide near-zero tailpipe emissions. With this approach, the reformer converts gasoline (or another hydrocarbon-containing fuel) into reformate, containing hydrogen and CO. Reformate has very wide combustion limits to enable SI engine operation under very dilute conditions (either ultra-lean or with heavy EGR concentrations). In previous publications, we have presented engine dynamometer results showing very low emissions with bottled reformate. This paper shows the sensitivity of engine emissions and performance to operating near the dilute limit with H2 enrichment using both bottled reformate and an actual reformer prototype. It discusses the additional advantages of the system for supplemental heating to the passenger compartment and the vision of substantially increasing powertrain efficiency - by using a solid oxide fuel cell (SOFC) APU as the source of reformate.