ISO 3046-4:2009 establishes a classification for the requirements and parameters of speed-governing systems and specifies terms and definitions of typical engine speeds for reciprocating internal combustion (RIC) engines. Where necessary, individual requirements are given for particular engine applications.

ISO 3046-4:2009 applies to RIC engines for land, rail-traction and marine use, excluding engines used to propel road-construction and earth-moving machines, agricultural and industrial types of tractors, road vehicles and aircraft. Also excluded are self-governing engines and those engines requiring only maximum speed or maximum fuel delivery limitation.

ISO 3046-4:2009 defines requirements for compression–ignition oil engines (diesel engines). For spark ignition engines and dual fuel engines, special requirements can apply.