Ford Duratec engine is a brand name of the Ford of Europe used for the company's range of gasoline-powered I3, I4, I5 and V6 passenger car engines.
The original 1993 Duratec V6 engine was designed by Ford and Porsche.
Over time, "Duratec" became an umbrella name for Ford's gasoline engines unrelated to the original V6.
The Ford Zeta engine, Ford Sigma engine and Ford Cyclone engine all carry the Duratec name, but are otherwise unrelated to each other or the original 1993 Duratec V6.
The ambiguous use of the name is similar to Ford's use of the Zetec for the previous generation of gasoline engines, the Duratorq name for diesel engines, and EcoBoost for turbocharged gasoline engines.