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. This work also discusses some limitations of the method, for example, when applied on non-usual bore honing, coated bores or nano-layered bores.