NOVELTY - A catalytic reformer assembly (150) for generating hydrogen-containing reformate fuel (11) from hydrocarbons, comprises a reactor (10); a reforming catalyst (16) disposed in the reactor; a heat exchanger (70) in fluid communication with the reactor; and a combustor in flow communication with the heat exchanger.    USE - The assembly is for generating hydrogen-containing reformate fuel from hydrocarbons. It is fluidly coupling to a fuel cell (174), which is a solid-oxide fuel cell (176); and internal combustion engine (170) or an exhaust steam of internal combustion engine (claimed), such as spark ignition engines and diesel engines, and hybrid vehicles (172). It is useful for vehicles including automobiles, trucks, and other land vehicles, boats, and ships, and aircraft including spacecraft.    ADVANTAGE - The assembly provides for rapid production of reformate and for steady state operation. It achieves reduced emission and increases light-off rate. Very rapid heating of the entire assembly at start-up is achieved. The non-productive time of the reformer is shortened.    DETAILED DESCRIPTION - A catalytic reformer assembly for generating hydrogen-containing reformate fuel from hydrocarbons, comprises a reactor; a reforming catalyst disposed in the reactor, and having an upstream side for receiving a gas flow and a downstream side for discharging a gas flow; a heat exchanger in fluid communication with the reactor, and having a first and a second flow side, where first flow side is in communication with the catalyst upstream side and the second flow side is in communication with the catalyst downstream side; and a combustor in flow communication with the heat exchanger including an air inlet for admitting air (13) to the combustor, a gas outlet in communication with the heat exchanger first side, a first fuel injector (166, 168) for injecting hydrocarbon fuel into the combustor to form a fuel/air mixture, and an igniter for igniting the fuel/air mixture to form hot exhaust gases (113) in the combustor, which gases may be passed through the heat exchanger first side, reactor, catalyst, and heat exchanger second side.    An INDEPENDENT CLAIM is also included for a method of operating a reformer assembly having a reactor including a catalyst, a heat exchanger, and a combustor, comprising admitting air into the combustor; injecting hydrocarbon fuel into the combustor from a first injector to form a first fuel/air mixture; igniting the first fuel/air mixture to form hot exhaust gases; passing the hot exhaust gases through a first flow side of the heat exchanger to heat the first flow side; passing gases exhausted from the heat exchanger through the reactor to heat the reactor and catalyst; passing gases exhausted from the reactor through a second flow side of the heat exchanger to heat the second flow side; and terminating ignition of the fuel/air mixture to terminate formation of hot exhaust gases.    DESCRIPTION OF DRAWING(S) - The figure is a cross-sectional view of a fast light-off catalytic reformer assembly.    Reactor (10)    Fuel (11)    Air (13)    Reforming catalyst (16)    Heat exchanger (70)    Hot exhaust gases (113)    Catalytic reformer assembly (150)    Fuel injector (166, 168)    Internal combustion engine (170)    Hybrid vehicles (172)    Fuel cell (174)    Solid oxide fuel cell (176)