Effect of Extreme Temperatures on Coated Piston Crown for CNGDI Engine

摘要

Due to high temperature and less proper heat transfer, the material of piston crown in an engine of compressed natural gas with a direct injection system (CNGDI) may lead to high thermal stresses and fails to withstand high temperature and operate effectively. By insulating with thermal barrier coating (TBC) such as ceramic-based yttria partially stabilised zirconia (YPSZ), heat transfer to the piston might be reduced and lead to improvement of piston durability. Hence, in this research, YPSZ coating was utilised to differentiate with the uncoated piston crowns in terms of the ability to reduce thermal penetration to the piston. A detailed finite element analysis (FEA) was carried out to determine the location of hotspots via profiles distribution of thermal. In short, it was observed that hotspots were mainly concentrated at the piston bowl's rim. The heat flux for the YPSZ/NiCrAl-coated from FEA exhibited about 98% reduction compared to the uncoated piston crown.