Abstract
Over the past decade, there has been a large push for the miniaturization of internal combustion engines. This is largely due to the relatively high energy density of hydrocarbons, which tend to be the preferred energy source of these engine types. This paper covers the multitude of scaling issues that remain prevalent in micro engine development, specifically focusing on engine displacements in the order of one cubic centimeter. The paper reviews obstacles caused by the disproportionate increase in the ratio of surface area to volume, including excess heat transfer as well as tribological factors. Issues caused by increased operational speeds are also addressed with special consideration given to residence and reaction time inequities. The fabrication limitations of these engines are also considered. Possible solutions to these scaling issues as well as promising applications are briefly discussed.