Honing

Abstract: In a hard roller burnishing operation, a hydrostatically borne ceramic ball rolls over the component surface under high pressures The roughness peaks are flattened and the quality of the workpiece surface is improved When combined with hard turning, this process provides a manufacturing alternative to grinding and honing operations The studies determined optimum working parameter ranges Parameter settings were shown to be non-critical in this process, since constant surface qualities were attainable over wide setting ranges A second phase of the studies examined the improvements obtained for various original roughnesses Reductions of 30 to 50 % in mean peak-to-valley height Rz are, for example, achievable, depending on the original roughness Structure analyses and residual stress measurements were used to examine the effects of the process on the workpiece surface zone Hard roller burnishing transforms tensile residual stresses present in the surface zone after hard turning into compressive residual stresses Hard roller burnishing has no effect on the formation of white layers in the surface zone

Abstract: A cylinder liner possesses fairly intricate surface requirements due to its complicated functions. It needs to provide adequate surface roughness to resist wear as well as to store and retain lubricants during high temperatures. The liner surface texture is anisotropic, produced by the honing process, with resultant deep visible scratches left on it [1] . The prominence of the honing grooves observed suggests that surface texture significantly affects ring-pack performance, although this effect is not clearly understood. In this paper, a numerical model was developed to investigate the effects of groove characteristics on the lubrication condition and friction at the interface between the piston ring and cylinder liner. This model aims to solve the average Reynolds equation, which depends on the real surface topographies of the cylinder liner, and describes the influence of surface irregularities on the lubricant flow under hydrodynamic lubrication conditions, considering lubricant film rupture and cavitations. Numerical results help to determine the optimum lateral groove characteristics to reduce friction and then noxious emissions.

Abstract: In this paper, a review of engineering coating for engine application is presented. Issues relating to dimensional stability, tribological properties, lubrication, coefficient of friction, hot hardness, amenability for honing, surface roughness and topography, residual stress, adherence, damage tolerance and resistance, pores density and conditions and cost performance are discussed. There exist advantages and limitations of conventional materials systems and techniques such as chemical-vapor-deposited diamond-like carbon (DLC) coating, plasma sprayed metal matrix composite coating, tribologically functional ceramic coatings, etc. Nano-grains of a crystalline phase hold promise to solve several such problems present in conventional coatings. In addition, surface-related problems are addressed for high performance engines and hydrogen powered automotive engines.

Abstract: The plateau honing operation is being widely used for finishing of cylinder liners for internal combustion engines Plateau honing has been shown to significantly reduce the costly running-in period due to the fact that very little further modification of the texture is required once the liner is put into operation In order to better understand, control, and ultimately “engineer” plateau honed surfaces, a comprehensive means of characterizing this texture is required In this paper the techniques currently used are briefly reviewed and an alternate approach is proposed The proposed approach is based on analyzing the cumulative distribution plot on a normal probability graph