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Considerable amount of research work on hydrogen fueled engines has been conducted for 17 years in Musashi Institute of Technology. The primary purpose of the research has been to develop a hydrogen powered autmobile, and in order to realized it, various innovations have been applied and tested. The newest outcome of this 17 years research was Musashi-7 Track, which demonstrated its performance in Innovation vehicle Design Competition held in Vancouver in July 1986. Musashi-7 Track was a modified medium duty truck, which was originally made by Hino Motors, and had a hydrogen powered engine. The track was equipped with 150 ℓ liquid hydrogen (LH2) tank and 8 MPa high pressure LH2 pump. The pump delivered 8 MPa high pressure hydrogen gas to the engine and the fuel was injected to a hot surface igniter in DI combustion chamber. This type of hydrogen enigne has following advantages. Firstly, fuel corrier weight and volume can be much smaller than those of metal-hydrides (MH).

A hydrogen powered vehicle system consisted of LH2 tank high pressure LH2 -pump, a device to inject hydrogen onto the hot surface, and ignitor in turbo-engine of CR 12:1 had been developed by Musashi Institute of Technology- Recently the authors applied this system to a medium duty truck produced by Hino Motors Ltd. Then following improvement were required. (1) Gas tightness and endurance of hydrogen injector were improved by the selection of material, size, finishing and by suppling a small amount of lubricating oil. (2) Mixture formation of the injected hydrogen with the compressed air was improved by tuning up the size and number of the nozzle holes and injection timing with the hydraulic pump and valve. (3) A small amount of hydrogen was supplied into the intake manifold. It reduced the combustion noise and also it recovered the evaporation loss in the LH2 -tank.

Oil film thicknesses of the piston top ring and the second ring of a truck diesel engine have been measured simultaneously by embedding capacitance type clearance sensors in the ring sliding surfaces. Owing to the above, several phenomena such as the variation in oil film thickness of each ring in one cycle, correlation between the rings, difference in oil film thickness between the thrust and counter thrust-sides, effects of engine operating conditions on oil film thickness, etc. have been determined. Efforts have been also made to analyze the causes of such phenomena according to the measured results of piston slap motion and ring motions, and the calculated results of oil film thickness.