Development of Elemental Technologies for Hydrogen Engines

Yasuyuki Murata･Hiroki Nagashima･Naoyoshi Nishigata･Ryo Iwashita･Saki Shiratori･Takeru Tagawa･Masato Watanabe (SUBARU)

As the realization of a carbon-neutral society becomes increasingly important, hydrogen fuel is gaining attention as a viable energy source. This study focuses on adapting an existing horizontally opposed engine for hydrogen combustion with minimal hardware modifications. Engine bench testing was conducted to evaluate its performance and durability under hydrogen-fueled conditions. This presentation reports on the reliability challenges identified through the validation process and discusses key considerations for future development of hydrogen engine hardware.

Changes in water content and elements in lubricant due to differences in operating conditions and cylinder wall temperature of a hydrogen engine and their effects on friction and seizure characteristics of engine bearings

Dengda Zhu･Yasuyuki Miyajima･Shinnosuke Higashino (Tokyo City University)･Takumi Iwata (MOTORA, Inc.)･Masakuni Oikawa (Tokyo City University)･Yusuke Iizuka･Rikuto Saito･Ko Onodera (ENEOS Corporation)･Yuji Mihara (Tokyo City University)

Water vapor generated by hydrogen combustion tends to condense on engine walls at low temperatures, leading to the emulsification of lubricant and the degradation of its lubrication performance. In this study, a single-cylinder hydrogen engine was operated for 33 hours to evaluate the lubricant’s emulsification behavior. Furthermore, the scuffing characteristics of fresh, emulsified, and dehydrated lubricants were compared using a bearing test rig, with a focus on the effects of lubricant additives.

Effects of changes in water content of lubricant oil due to combustion in hydrogen engines on friction characteristics of piston systems.

Shinnosuke Higashino･Yasuyuki Miyajima･Dengda Zhu (Tokyo City University)･Takumi Iwata (MOTORA, Inc.)･Masakuni Oikawa (Tokyo City University)･Yusuke Iizuka･Rikuto Saito･Ko Onodera (ENEOS Corporation)･Yuji Mihara (Tokyo City University)

In hydrogen internal combustion engines, the mixing and emulsification of water produced by hydrogen combustion into the lubricant is an issue.
In this study, therefore, we used a floating liner engine to evaluate the physical properties of lubricant oils containing a specific percentage of water , and also measured and evaluated the friction characteristics of these lubricants under fixed conditions. We also performed an evaluation using lubricant after evaporating the mixed water.