In automobile manufacturing, assembly or maintenance, the assembly is usually regarded as an independent structural unit to organize production. Some main automobile assembly should be tested according to certain technical specifications before loading. In automobile repair, assembly exchange method is sometimes adopted, that is to remove a certain assembly from the vehicle and replace it with a new or repaired and qualified assembly, which can shorten the time of automobile repair and is conducive to the organization of repair work and the improvement of operation quality.

In short: assembly is a series of products to form a whole, to achieve a specific function of the general term of the parts system. Assembly is the meaning of assembly.

For example: the automobile transmission shaft assembly, that is: the collection of various transmission shaft related parts, can realize power transmission.

Engine assembly refers to the overall synthesis meaning, including internal combustion engine, starter, oil pump and so on. It is a complete working machine, so it is called assembly.