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Development of the Nitrogen Fixation System which is one of the subsystem of Closed Ecological Life Support System(CELSS) is necessary for the purpose of synthesizing nitrogen fertilizer, ammonia and ammonium nitrate, for plant cultivation in the closed system. Up to now, nitrogen fixation process has been established as ammonia synthesis using nitrogen and hydrogen in the industrial field, and ammonia is further oxidized to obtain the nitrate to be used for plant cultivation. The nitrogen fixation process consists of the subsystems for ammonia synthesis, ammonia separation, and nitric acid synthesis. Nowadays, this nitrogen fixation system has been put to practical use in the large commercial plant, however the system for CELSS is still developing technology. Considering such particular condition as for CELSS, it is needed for the total system to satisfy some important requirements such as safety, energy saving, compactness, maintainability and so on.

In order to improve the drawbacks of current schnürle-type two-stroke gasoline engine, a reverse uniflow-type two-stroke direct injection engine was designed and developed. The scavenging port and piston geometry combined with a direct injection system were designed to realize both stratified charge combustion in light to medium load and higher power output in high load range. In-cylinder gas motion and spray behavior were analyzed and optimized by numerical simulation. The experimental result shows high BMEP in WOT operation achieved by a high delivery ratio, high trapping efficiency and good scavenging. In light to medium load a stable combustion was achieved by good stratified combustion utilizing a spray and wall guided mixture preparation.