Performance Characteristics of a Low Heat Rejection Direct-Injection Military Diesel Engine Retrofitted With Thermal Barrier Coated Pistons

Abstract

A special two-cylinder military specific power plant was employed to evaluate the effect of thermal barrier coated pistons on overall engine performance at simulated low heat rejection-type operating conditions. This study focused on three combustion systems including a noncoated baseline ductile iron piston along with zirconia and chrome-oxide sealed zirconia coated analogs. For the test matrix encompassing ten full and half-load operating conditions, both coated piston combustion systems yielded a detrimental effect on fuel economy in comparison to the baseline combustion system at constant fueling and air consumption rates. These performance differences were attributed to a combination of combustion phasing modulations, injection timing discrepancies, and sluggish combustion associated with the zirconia coated piston configurations.