First, several technological problems pertaining to the recycle and closed-cycle diesel engines, but different from the problems of general air environment operation engines, were extracted and the expected engine cycle was discussed from a thermo-dynamic viewpoint.
Then, land-based testing equipment for the recycle engine was manufactured for a trial, with intention to develop an underwater power source. With the equipment, experiments were carried out to look into the working and the performance of the engine. Furthermore, the equipment was modified and made into a closed-cycle diesel engine for a trial and experiments were conducted. The test results were compared with the results of the thermodynamic analysis, and the suitability of the analysis method was evaluated.
Subsequently on the basis of these data, we succeeded in developing under-water practical power source “HIRUP”.