Engine is a machine that can convert other forms of energy into mechanical energy, including internal combustion engines (reciprocating piston engines), external combustion engines (Stirling engines, steam engines, etc.), jet engines, electric motors, etc. For example, internal combustion engines usually convert chemical energy into mechanical energy. The engine is not only applicable to the power generating device, but also refers to the entire machine including the power device (such as: gasoline engine, aviation engine). The engine was first born in England, so the concept of engine also originated from English, and its original meaning refers to the kind of "mechanical device that generates power."