Study on the tribological behaviors of the cylinder liner-piston ring in the ammonia-fueled engine

As a hydrogen-rich carbon-free fuel, ammonia fuel has recently attracted considerable attention in the engine field. However, few studies on the tribological properties of ammonia-fueled engines have been reported, which limits the development of ammonia-fueled engines. In this study, the tribological behaviors of the cylinder liner‒piston ring (CLPR) were studied under dry friction, water, and ammonia solution media. The results indicated that both the water medium and the ammonia solution medium have a certain lubricating effect. The main wear mechanism of CLPR in dry friction is abrasive wear. In both the water medium and the ammonia solution medium, the surface damage to the CLPR was dominated by tribocorrosion, but their action mechanisms were completely different. The presence of ammonia causes the microelectrolytic reaction of the CLPR and changes the tribological behavior of the CLPR.