The DFV is an internal combustion engine that was originally produced by Cosworth for Formula One motor racing. The name is an abbreviation of Double Four Valve, the engine being a V8 development of the earlier four-cylinder FVA, which had four valves per cylinder.

Cosworth is a British automotive engineering company founded in London in 1958, specialising in high-performance internal combustion engines, powertrain, and electronics for automobile racing (motorsport) and mainstream automotive industries. Cosworth is based in Northampton, England, with facilities in Cottenham, England, Silverstone, England, and Indianapolis, IN, US.