An engine is a machine that can convert other forms of energy into mechanical energy, including, for example, an internal combustion engine (gasoline engine, etc.), an external combustion engine (Stirling engine, steam engine, etc.), an electric motor, and the like. For example, internal combustion engines usually convert chemical energy into mechanical energy. The engine is applicable to both the power generating device and the entire machine including the power unit (eg, gasoline engine, aero engine). The engine was first born in the UK, so the concept of the engine is also derived from English, and its original meaning refers to the "mechanical device that generates power."