NOVELTY - The hydrogen-producing catalytic converter comprises: a catalyst bed (30) including a molecular rearrangement duct and a coolant conveying duct, where the molecular rearrangement duct is communicable with an intake manifold of an engine via a hydrogen adding pipeline and has a set of hydrogen-producing catalysts, and the coolant conveying duct is communicable with a coolant tank; and a preheating body (20) having a preheating duct having an end communicating with a fuel-water solution tank and another end communicating with the molecular rearrangement duct.    USE - The hydrogen-producing catalytic converter is useful for absorbing heat from waste gas discharged from an exhaust pipe of an engine (all claimed) for actuating hydrogen production, where the engine is an internal combustion engine and useful in a car.    ADVANTAGE - The hydrogen-producing catalytic converter efficiently absorbs the engine waste heat for producing the hydrogen gas and delivering the produced hydrogen gas into the engine, so that fuel in the engine can be completely burned to reduce air pollution and save fuel.    DETAILED DESCRIPTION - The hydrogen-producing catalytic converter comprises: a catalyst bed (30) including a molecular rearrangement duct and a coolant conveying duct, where the molecular rearrangement duct is communicable with an intake manifold of an engine via a hydrogen adding pipeline and has a set of hydrogen-producing catalysts, and the coolant conveying duct is communicable with a coolant tank; a preheating body (20) having a preheating duct having an end communicating with a fuel-water solution tank and another end communicating with the molecular rearrangement duct, where the preheating body and the catalyst bed are arranged end-to-end in an exhaust pipe section with the preheating body located closer to the engine; a heating pipe that is externally fitted around the preheating body and the catalyst bed and comprises two closed ends, where one of the two closed ends has a gas inlet pipe connected to communicate the heating pipe with a combustion gas tank, and the other closed end of the heating pipe is provided with pressure relief vents; and a set of heating catalysts filled between the heating pipe and the preheating body and the catalyst bed. The heating catalysts are heated by a combustion gas fed from the combustion gas tank into the heating pipe. The heated heating catalysts in turn heat the catalyst bed and the preheating body. The catalyst bed further includes a first temperature sensor (33) and a second temperature sensor (34). A fuel-water solution is supplied from the fuel-water solution tank into the preheating duct in the preheating body when the first temperature sensor detects a temperature reaching a working temperature of the hydrogen-producing catalysts for hydrogen production. A coolant is supplied from the coolant tank into the coolant conveying duct in the catalyst bed when the second temperature sensor detects a temperature reaching a safe temperature preset for the hydrogen-producing catalysts. The catalyst bed is provided at a front end surface opposite to the preheating body and a rear end surface with a set of front and rear recesses, respectively. The front and rear recesses are provided with two axially extended through holes. The two through holes at any one of the front recesses of the catalyst bed are communicable with two adjacent rear recesses of the catalyst bed. The front recesses and the rear recesses of the catalyst bed are closed by front sealing plates and rear sealing plates, respectively, so that the molecular rearrangement duct forms a zigzag duct consisting of a set of sequentially communicable duct sections. The preheating body is provided at a front end surface adjacent to the catalyst bed and a rear end surface with a set of front and rear recesses, respectively. The front and rear recess are provided with two axially extended through holes. The two through holes at any one of the front recesses of the preheating body are communicable with two adjacent rear recesses of the preheating body. The front recesses and the rear recesses of the preheating body are closed by front sealing plates and rear sealing plates, respectively, so that the preheating duct forms a zigzag duct consisting of a set of sequentially communicable duct sections. The combustion gas is supplied from the combustion gas tank into the heating pipe by an air pump. The air pump immediately stops supplying the oxygen-containing combustion gas when the hydrogen-producing catalysts in the catalyst bed are heated by the heating catalysts in the heating pipe to a working temperature. The preheating body and the catalyst bed are provided on around their outer wall surfaces with three angularly equally spaced and axially extended support wings. The heating pipe is correspondingly provided on its inner wall surface with axially extended engaging slots. The preheating body and the catalyst bed are fixedly held in place in the heating pipe through the engagement of the support wings with the engaging slots. The preheating body and the catalyst bed are welded together to form an integral unit. The support wings are respectively provided with a hole. Gases in the heating pipe are allowed to flow laterally through the holes provided on the support wings without being blocked by the support wings. The heating pipe is fixedly held in the exhaust pipe section by two sets of three angularly equally spaced screws, which are provided on the exhaust pipe section near both front and rear ends to radially extend into the exhaust pipe section to press against front and rear end portions of the heating pipe.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic perspective view of a catalyst bed and a preheating body included in a hydrogen-producing catalytic converter.    Preheating body (20)    Catalyst bed (30)    First temperature sensor (33)    Second temperature sensor (34)    Coolant conveying pipeline. (321)