Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.
In this paper, we present our experimental research on a power pack based on the linear engine operating conditions and the linear generator structure for generating electric power. The power pack used in the study consisted of a two-stroke freepiston linear engine, linear generators, and air compressors. Each parameter of input caloric value, equivalence ratio, spark timing delay, electrical resistance, and air gap length were settled for identifying the combustion characteristics and for examining the linear engine performance. The linear engine was fueled with propane, and in the course of all its operations, intake air was fed under the wide open throttle condition. The air and fuel mass flow rate were varied by a mass flow controller and premixed by a pre-mixing device. The premixed gas was then directly supplied into each combustion cylinder. The experiments confirmed that power generation was induced differently for each respective operating condition. For the linear engine, piston frequency, velocity, and combustion characteristics were ultimately different for each operating condition. As a result, the piston frequency was 57.2Hz and the maximum generating power was 111.3W, where the operating conditions were as follows: 1.0 of equivalence ratio, 1.5ms of spark timing delay, 30Ω of electric resistance, and 1.0mm of air gap length.