They usually use Unreal Engine 3 for some of their games but it seems the company is planning to stop relying on such engines entirely. (gamechup.com)
Such engines normally get started by burning oil, but are then driven by gas. (newscientist.com)
The «E» designation appeared at the end of the name of any car bearing such an engine, and after nearly 63 years of use, it became its own classification. (dupontregistry.com)