Developing Custom Engine Test and Solutions for Handling Water in Lubricants for Hydrogen Internal Combustion Engines

Hydrogen internal combustion engines (H₂–ICEs) are being evaluated as a potential pathway for lowering the CO₂ emissions intensity of the transportation and the power generation sectors as well as off-road applications such as agriculture and construction industry. H₂–ICEs offer several advantages to the Original Equipment Manufacturers (OEMs); such as retaining the existing engine architecture and hardware, whilst achieving a lower emissions intensity than diesel engines. Some of the key challenges for the H₂–ICEs operation are managing excessive amounts of water build-up in the oil under certain operating conditions and pre-ignition which have significant impact on the engine life and durability. In the current study, the authors developed a custom test cycle using a 7.4-litre 6-cylinder turbo-charged hydrogen engine designed for combined heat and power applications. The test cycle was created with the purpose of accumulating significant amounts of water (hydration phase) in the oil, allowing the oil-water mixture to remain in the engine for an extended period to initiate and propagate corrosion, and a high load phase to expel most of the water from the oil. During the hydration phase, oil water content exceeded 10%, while in the dehydration phase, the water was completely evaporated out of the lubricant. The engine test successfully validated the bench test findings, identified key engine operating parameters influencing water accumulation in the engine oil, and differentiated two oils based on improved emulsion characteristics and higher corrosion resistance.