Contrary to expectations, lubricants showed no significant signs of degradation in two heavy-duty hydrogen-fueled internal combustion engines, finds newly published research by Southwest Research Institute.
Development of hydrogen ICEs is gathering momentum, and many jurisdictions around the world are promoting hydrogen ICEs as key to decarbonizing transport. According to the U.S. Department of Energy, 130 original equipment manufacturers around the world have an interest in hydrogen ICE research and development. And unlike hydrogen fuel cell vehicles, conventional ICEs can be converted to hydrogen.
There have been concerns about how lubricants will perform in an engine where water is a combustion product. For example, excessive water could lead to creation of acids in the lubricant. SWRI set up a hydrogen ICE joint industry program “to develop and demonstrate the feasibility of hydrogen-powered engines for heavy-duty applications” and to investigate the major issues with lubricant performance in hydrogen ICEs.
The institute tested Cummins X15N and Daimler DD15 engines that were converted to run on hydrogen. The results found that there was very low water accumulation in the lubricants and that lubricant performance remained stable, with minimal changes in viscosity, total acid number and total base number. There were also near-zero greenhouse gas and ultra-low nitrogen oxides and particulate matter.
SWRI cautioned that while they found the lubricants in two heavy-duty hydrogen ICEs performed well in steady-state, warm conditions, they may or may not be as stable at low temperatures and in cold-start scenarios.