Switchable turbocharging system

The invention relates to a switchable turbocharging system, belonging to the technical field of internal combustion engines. The switchable turbocharging system comprises two air compressors, an air inlet pipe, an engine, a gas exhaust pipe, two turbines, a volume chamber, connecting pipes, a moving body, a spring and two penetrating pipes, wherein the moving body is mounted in the volume chamber and is in sealed contact with the internal wall face of the volume chamber, both the first penetrating pipe and the second penetrating pipe penetrate through the left wall face and the right wall face of the moving body, and the upper wall face of the moving body is connected with the upper wall face of the volume chamber through the spring. When the engine is in low-speed working condition, the moving body moves upwards, only the first air compressor and the first turbine work, pulse energy is fully utilized, the inlet air pressure of the engine is higher, and the whole performance of the engine is better; and when the engine is in high-speed working condition, the moving body moves downwards, the first air compressor, the second air compressor, the first turbine and the second turbine simultaneously work, the pumping loss of the engine is less, and the whole performance of the engine is better. The switchable turbocharging system is reasonable in design and simple in structure and is applicable to a turbocharging system with two turbochargers.