NOVELTY - Fuel and air flow rates (I) are set in reformer (01) to form fuel/air mixture (I) (14). Mixture (I) is provided to reformer and is ignited at least once. Ignition-exhaust products are passed through reforming catalyst (16). Flow of fuel (11) into the reformer is terminated. Fuel and air are flown at flow rates (II) to form mixture (II) which is then contacted with the catalyst for reformation.    USE - For starting fast light-off catalytic reformer for converting hydrocarbon fuel and air to reformate, used in land vehicles, boat, ship, aircraft, spacecraft and fuel cell e.g. solid-oxide fuel cell (all claimed).    ADVANTAGE - The starting method enables rapid production of reformate for hydrogen coldstart in an internal combustion engine. The start-up combustion reaction is quenched to initiate reforming of fuel. The changing over from combustion mode to reforming mode, is quick without the need for a flame arrester and also without coking of the catalyst surfaces. The control system selects fuel and air flow delivery rates and operates the ignition device to achieve fast light-off of the reforming catalyst at start-up and to maintain the catalyst at a temperature sufficient to optimize reformate yield. The method provides rapid production of high yields of reformate by not coking the catalyst during mixture changeover and is particularly used for on-board fuel reforming, especially with larger, high-emission vehicles. The produced reformate can be bottled in a vessel or used for fuel power generation systems such as spark ignition engines, hybrid vehicles, diesel engines, and fuel cells.    DETAILED DESCRIPTION - A fuel flow rate (I) and an air flow rate (I) are set in a reformer (01) to form fuel/air mixture (I) (14) having a preset mass ratio (I). The fuel/air mixture is provided to the reformer for a preset length of time (I). The fuel/air mixture is ignited with an ignition device (22) within the reformer at least once during time (I). The exhaust products of the ignition are passed through a reforming catalyst (16) to raise the temperature. The flow of fuel (11) into the reformer is terminated at the end of time (I), and preset length of time (II) is started. The ignition action in the reformer is terminated. At the end of time (II), fuel and air are flown into the reformer at fuel flow rate (II) and air flow rate (II) to form fuel/air mixture (II) having a preset mass ratio (II).    Fuel/air mixture (II) is then passed into contact with the catalyst to reform the mixture into reformate. The reformer has a reactor tube (10), a reforming catalyst disposed within the reactor tube, an ignition device for igniting a fuel/air mixture within the reactor tube, and a control system (30) for controlling fuel and air flow rates into the reactor tube and for controlling the ignition device.    An INDEPENDENT CLAIM is included for vehicle comprising a hydrocarbon fuel reformer which is started-up by the starting-up method.    DESCRIPTION OF DRAWING(S) - The figure shows an isometric view, partially in section, of a fast light-off catalytic reformer.    reformer (01)    reactor tube (10)    fuel (11)    fuel/air mixture (14)    reforming catalyst (16)    ignition device (22)    control system (30)