Shaping the surface layer of an internal combustion engine piston skirt using ablative laser micromachining

This paper presents the concept and technology for shaping the surface layer of an internal combustion engine piston skirt using ablative laser micromachining. In order to reduce the friction work of the piston skirt against the cylinder liner bore, hemispherical oil micro-reservoirs were created through laser texturing. Measurements of the oil reservoir geometry and surface topography were performed. It was found that the adopted assumptions show promise for improving the performance of the piston skirt-cylinder liner bore interface.The piston consists of the following structural elements: the crown, the ring belt, the skirt, and two bosses serving as the bearing for the piston pin [1-2].
The piston performs many critical tasks in an engine. Its crown constitutes the moving part of the combustion chamber and is therefore exposed to high pressure and high temperatures.
Pressures reach 7-15 MPa, while temperatures are approximately 250-500°C. The piston design must ensure heat dissipation from the crown and allow for the seating and guidance of the piston rings that seal the combustion chamber. In addition to these tasks, the piston must also meet further requirements. (…)

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