Free-piston generator

The invention relates to combustion engine and power generation fields. It includes excitation winding, stator, stator winding, left and right separating poles, internal combustion engine jar and cover, combustion chamber, bouncing chamber, gas mixture injector, air outlet, current inverter, switch, and storage battery. Its features are that free piston armature can be used as free piston and the armature; the stator inner is set inner combustion engine jar; two stator windings are respectively coiled around the left and right separating poles; the inner combustion engine jar inner is free piston armature; and its one end is the cover on which gas mixture injector and air outlet are set. The invention combines the inner combustion engine and power generator, can simplify the device, reduce processing cost, transform mechanical energy into electric engine, avoid energy loss while machine driving, and acquire higher energy conversion ratio.