Lubricant Performance and Reliability of Ammonia Fueled Internal Combustion Engines

Abstract

<div class="section abstract"><div class="htmlview paragraph">Using ammonia as a fuel has been experimented since the nineteenth century in different types of ground and air vehicles but it was never able to replace fossil- based hydrocarbon fuels at scale. Nevertheless, this concept has gained a new momentum following recent policies to significantly reduce greenhouse gas emissions in fuel intensive sectors such as power generation and transportation. Following the strategy of the International Maritime Organization (IMO) to reduce the carbon intensity from international shipping by at least 50 percent by 2050, the implementation of zero-carbon fuels on a tank to wake basis, such as ammonia, is being strongly considered by the maritime ecosystem. Additionally, initiatives from other industries have emerged recently, demonstrating a broader interest in ammonia fuel for sustainable operations such as heavy duty and off-road applications. Whereas its toxicity and handling protocols fuel numerous discussions and working groups, ammonia reactivity and possible interactions with the combustion engine also rise concerns. In particular, the adequation between ammonia combustion and engine lubrication system could be of paramount importance to ensure reliable engine operations over the lifetime of the equipment.</div><div class="htmlview paragraph">This study investigates the impact of ammonia combustion on engine lubrication based on specific engine tests and lubricant ageing procedures. A 4 stroke Diesel internal combustion engine was modified to operate in dual-fuel mode with ammonia on steady state operating points. Different engine lubricants were tested, and oil samples were taken over extended periods of time to evaluate engine behavior in combination with final engine inspections. Analytical techniques and laboratory performance tests were performed to study the evolution of lubricant properties under ammonia-powered engine operations. Results provide novel insights on ammonia engine reliability and compatibility of engine oil composition with ammonia.</div></div>