NOVELTY - Integrated fuel reformer-engine system comprises an on-board solid oxide fuel cell reformer, an engine, an exhaust catalyst and a controller.    USE - For providing low hydrocarbon and NOx emissions in internal combustion engines over a range of operating conditions.    ADVANTAGE - The invention is capable of robustly meeting super ultra low emission vehicle emissions criteria over the range of real-world operating conditions. It enables reduction of hydrogen and NOx emissions to near zero at cold start to periods of vehicle road loads. It reduces exhaust emissions while providing fuel economy and overall engine efficiency. It can be adapted to variety of vehicle types, including larger, higher emitting vehicles, such as those employing diesel engines.    DETAILED DESCRIPTION - An integrated fuel reformer-engine system (10) comprises an on-board solid oxide fuel cell reformer (12) for receiving a supply of hydrogen-containing liquid fuel and a supply of air (16a, 16b) and converting same into a hydrogen-rich reformate (18a, 18b); an engine (20) having a reformate intake, a liquid fuel intake, an air intake, and an exhaust outlet; an exhaust catalyst having an intake for receiving the engine exhaust (22) and/or the reformate, and an outlet for discharging the exhaust after treatment; and controller for adjusting the supply of air or a combination of the reformate and the liquid fuel to the engine and for adjusting the supply of reformate to the exhaust catalyst to provide non-stoichiometric lean fueling of the engine and to provide low hydrocarbon and nitrogen oxides (NOx) emissions over a range of operating conditions from cold-start to high engine loads.    An INDEPENDENT CLAIM is also included for a method of operating an integrated fuel reformer-engine system comprising producing a hydrogen-rich reformate fuel with an on-board solid oxide fuel cell fuel reformer; fueling an engine with reformate and/or liquid fuel; treating engine exhaust and/or reformate in exhaust catalyst; and controlling the supply to the engine and the exhaust catalyst of reformate and/or liquid fuel, and air to provide non-stoichiometric lean fueling of the engine and achieve low hydrocarbon and NOx emissions over range of engine operating conditions from cold-start to high engine loads.    DESCRIPTION OF DRAWING(S) - The figure is a block schematic view showing a reformer-based cold start system.    Integrated fuel reformer-engine system (10)    On-board solid oxide fuel cell reformer (12)    Air (16a, 16b)    Hydrogen-rich reformate (18a, 18b)    Engine having reformate intake (20)    Engine exhaust (22)