A review: Centurial progress and development of Wankel rotary engine

Wankel rotary engine (WRE) featured high power density, compact structure and smooth operation takes advantage of the powertrain assembly and has been highly valued by many countries and regions. However, under the restriction of increasingly strict emission regulations, the development of WRE is gradually depressed, and WRE begins to fade out of the sight of the public and is only active in a few fields. Fortunately, many scholars and institutions are still contributing to the development of WRE. In nearly-one century since the WRE was proposed, a large number of studies on WRE have emerged that need to be organized and comprehensively to provide guidance for the subsequent development of WRE. This work is designed to present a comprehensive review of WRE's centurial progress and development from aspects of fuel selection and supply, sealing and friction, cooling, combustion chamber design, etc. First of all, the characteristics of WRE are introduced and a nearly centurial history of WRE is provided to better understand WRE. Secondly, the progress, development and application of WRE are reviewed. Finally, the key issues of the further commercialization and development of WRE are discussed.