Thermal Protection of Internal Combustion Engines Pistons

摘要

The research aiming to improve the reliability and durability of internal combustion engines (ICE) has traditionally been relevant. Today, the use of ceramic materials and coatings in engine manufacturing is an increasingly frequent research subject. The most promising method to form such coatings on aluminum-alloy pistons is microarc oxidation (MAO). The goal of this research is to study the efficiency of thermal protection provided by a MAO layer on the piston head experimentally. To determine the optimum coating thickness, we have simulated the thermal state of the piston using ANSYS Multiphysics. Then we carried out motor tests of the pistons using the single-cylinder unit of a four-cylinder two-stroke engine. The coating was applied to the surface of the piston head on the combustion chamber side. We tested the pistons with MAO coating thicknesses of 76 and 106 urn. The piston temperature was measured on the piston head surface on the crankcase side using temperature indicators. The tests were carried out under excess air factor α=0.95 at the full-load curve. As a result, we have elicited the positive effect of MAO coating applied to the piston head. Per calculation and test results, such coating reduced the temperature of the piston by 45...78 °C. The thickness of the MAO layer was not found to have any significant impact on the thermal state of the piston. The research results are applicable in engine manufacturing when designing new engines or upgrading the existing engines to make them more reliable.