| 總結: | High temperature produced in a compressed natural gas with direct injection system (CNGDI) engine may contribute to high thermal stresses. Without appropriate heat transfer mechanism, the piston crown would operate ineffectively. In this work, bonding layer NiCrAl and ceramic based yttria partially stabilized zirconia (YPSZ) were plasma sprayed onto AC8A aluminum alloy CNGDI piston crowns and normal CamPro piston crowns in order to minimize thermal stresses. Several samples were deposited with NiCrAl bonding layers prior to coating of YPSZ for comparison purpose with the uncoated piston. The performance of the coating against high temperature was tested using a burner rig. The temperatures on the top of piston crown and piston underside were measured. Finally, the heat fluxes of all conditions of piston crown were calculated. In short, the YPSZ/ NiCrAl coated CNGDI piston crown experienced the least heat fluxes than the uncoated piston crowns and the coated CamPro piston crown, giving extra protection during combustion operation. © 2013 The Authors. Published by Elsevier.
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