there is a lot of ingenious engines. The question is which one can be made into practically usable product. There is even productized version of rotary-vane en

there is a lot of ingenious engines. The question is which one can be made into practically usable product. There is even productized version of rotary-vane engine coming supposedly next year in a Russian car: http://www.fastcompany.com/1709400/russian-billionaire-unleashes-countrys-first-hybrid-vehicle http://www.fastcompany.com/1709400/russian-billionaire-unlea... I'd be though very surprised if they pull it off as beside Mazda rotary i don't know other mass-produced cars with non-traditional engines.