Design of a resonant micro reciprocating engine for power generation

Structure and performance of a silicon based micro reciprocating engine have been designed. The Otto cycle with hydrogen fuel has been adopted for the working cycle. The micro reciprocating engine is composed of opposite-pistons supported by an elastic spring. Resonant mode of the elastic spring is excited due to combustion pressure to increase the generated electric power. Theoretical electric power was found to be /spl sim/40 mW under the conditions that the compression ratio is 5, the maximum combustion temperature is 850 K and the first resonant frequency of the elastic spring is 610 Hz. The micro engine can be expected to use as a portable micro power generator with high energy density.