NOVELTY - System of decomposing ammonia comprises liquid ammonia bottle (1), electric-control valve (2), heat exchanger (3), cooler (6), high-pressure air pump (8) and high-pressure hydrogen-storage bottle (7); vaporizing chamber (22) and heating cracker (5); and second gas inlet (5c) of heating cracker connected to gas discharge port of thermo engine (9), and upper side of heating cracker equipped with a second gas outlet (5d).    USE - System of decomposing ammonia for producing hydrogen (claimed).    ADVANTAGE - The hot gas discharged from thermo motor (like an internal-combustion engine) after operates is used as heat source to decompose ammonia and produce hydrogen, thus satisfying hydrogen consumption of thermo motor; low-power electrical heating uses internal-combustion engine for starting or afterheat of low-speed-operation-discharged gas not sufficient to generate hydrogen used as energy source for combustion, and thermal value of the hydrogen as high as three times of petroleum, water and ammonia generated after combustion discharged into atmosphere directly, and catalytic discharging device used to eliminate micro-nitrogen oxide, thus no environmental contamination; and discharges at low temperature after heat exchange, and reduces temperature-raising effect caused by internal-combustion engine generated to the atmospheric environment.    DETAILED DESCRIPTION - System of decomposing ammonia comprises liquid ammonia bottle (1), electric-control valve (2), heat exchanger (3), cooler (6), high-pressure air pump (8) and high-pressure hydrogen-storage bottle (7); vaporizing chamber (22) and heating cracker (5); air outlet of liquid ammonia bottle connected to inlet of the vaporizing chamber through electric-control valve, outlet of vaporizing chamber connected to tube pass inlet (3a) of the heat exchanger, tube outlet (3b) of heat exchanger connected to first gas inlet (5a) of heating cracker, first gas outlet (5b) of the heating cracker connected to shell side inlet (3c) of heat exchanger, shell side outlet (3d) of heat exchanger connected to gas inlet of the cooler, gas outlet of cooler connected to gas inlet of the high-pressure air pump, outlet of high-pressure air pump connected to gas inlet valve (7a) of high-pressure hydrogen-storage bottle; and second gas inlet (5c) of heating cracker connected to gas discharge port of thermo engine (9), and upper side of heating cracker equipped with a second gas outlet (5d).    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of the system of decomposing ammonia.    Liquid ammonia bottle (1)    Electric-control valve (2)    Heat exchanger (3)    Tube pass inlet (3a)    Tube outlet (3b)    Shell side inlet (3c)    Shell side outlet (3d)    Heating cracker (5)    First gas outlet (5b)    Second gas inlet (5c)    Second gas outlet (5d)    Cooler (6)    High-pressure hydrogen-storage bottle (7)    Gas inlet valve (7a)    High-pressure air pump (8)    Thermo engine (9)    Vaporizing chamber (22)