Transportation vehicle power composition output device

The utility model relates to a transportation vehicle power output composition device which is provided with two engines and consists of a medium engine, a compact engine, an intermediate castellated shaft and a shifting yoke provided with a changeover lever. The crank of the medium engine is provided with a crankshaft gear, and so does the crank of the compact engine. The intermediate castellated shaft is provided with two slide gears which can make longitudinal movement, a stationary gear and a flywheel by splines. The stationary gear is in mesh with the gear on a belt pulley shaft with a belt pulley. The device is suitable to the machines which have big operating load change. When high power of the engine is needed, the medium engine and the compact engine work at the same time to satisfy design requirement. The medium engine works when running without full load (medium load), and the compact engine works when running without load. Disposing engine in such a way enables fuel oil to display maximal efficacy and save energy and reduce air pollution.