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One of the most promising applications for the use of hydrogen in vehicles is in the combustion engine. According to the legislation proposal being considered by European Union, hydrogen internal combustion engines (H2ICE) are zero emissions solution. Among the existing solutions, H2ICE is becoming the preferred one on long haul trucks and offroad applications. This is due to the high durability of the powertrain, the lower initial investment when compared to other alternatives, and the possibility of using low purity hydrogen. However, despite the high potential use of hydrogen, because of it is the smallest known chemical element, its use can result in the penetration of hydrogen into metallic materials, with the undesirable effect of embrittlement. This effect occurs mainly when the material surface is exposed to high temperatures and pressures, or under corrosion.

In the last years, sophisticated analyses and control of topography parameters have been introduced to study engine bore cylinders. Such surface characteristics have impact on friction and wear of the engine, with effects on fuel consumption and durability. Among such characteristics, folded metal blocking the honing grooves has received much attention, but its quantification and actual impact on engine performance is still under discussion, both in the academia and in the industry. In this work, a methodology was developed to mathematically quantify the folded metal present in engine bores. The method is compared to others described in the literature and in use by some European automotive manufacturers. The quantification method, based on topography measurements, was also compared with other analyses, such as optical and scanning electron microscopy. The necessary resolution of the topography measurement and some recommendations for the analysis are given.