Design and Fabrication of a Micro Reciprocating Engine

This paper presents an ongoing project of developing a micro reciprocating internal combustion engine. The engine is designed on the basis of a two stroke piston engine, but heavy modifications have been made to suit the 2D MEMS fabrication. All the engine parts are located in two layers. Piston seals are not used and leakage is prevented by the introduction of microgrooves on the piston, tight tolerance control and an extended contact area between the piston and the cylinder. With the assistance of a film of lubrication oil, these measures prove effective in preventing leakage. A new approach has been developed to fabricate high temperature resistant engine components at low cost. The approach relies on the UltraThick SU-8 Process (UTSP) to make micromoulds; then ceramic and metallic engine components can be produced based on the moulds. The UTSP is a UV lithography process for producing up to 1000 ?m thick SU-8 layers and the quality of the fabrication results can be compared with those made by using X ray exposure process in the same thickness. A complete microengine has been fabricated in SU-8 using the UTSP for test drive. High quality ceramic and metallic components have been produced based on the SU-8 moulds, proving the new approach is feasible for building