This is a category for internal combustion engine designs which have been proposed and have received sufficient development and/or publicity to warrant a Wikipedia article, but which have not yet found any commercial application.
They may be at many stages of development. They may be patented and/or have been demonstrated. Development may be under way, abandoned, or being actively promoted.
Pages in category "Proposed engines"
The following 13 pages are in this category, out of 13 total. This list may not reflect recent changes (learn more).