Startup mechanism and power distribution of free piston Stirling engine

Abstract

The startup mechanism and power distribution of free piston Stirling engine (FPSE) are different from the traditional crank connecting Stirling engine. All the time, there is no paper to study the startup mechanism and power distribution of FPSE. In this paper, three necessary conditions of startup of FPSE have been first proposed. Theoretical analysis and numerical simulation have been used to illustrate the α, β and γ types FPSEs whether meet the startup conditions. Related experiments have been done to prove the theoretical analysis and numerical simulation on an α and a β type FPSEs. According to the theoretical analysis, numerical simulation and experiments, some important results have been obtained. If a FPSE works stably, during a complete cycle, not only the total work in compression and expansion space should be positive, but also the work done by gas to both piston and displacer should be positive. To the α type FPSE, over a complete cycle the work done by gas to piston is negative and the work done by gas to displacer is positive. It does not meet the startup conditions. Therefore, the α type FPSE is impossible to startup. To the β and γ type FPSEs, over a complete cycle the work done by gas to displacer is positive. However, over a complete cycle the work done by gas to piston could be positive or negative. So it maybe meet the startup conditions of FPSE or not. So the β and γ type FPSEs could start up or not. Whether the β and γ type FPSEs could start up depends on the engine design and parameters configuration.