Performance characteristics of a low heat rejection direct-injection military diesel engine retrofitted with thermal barrier coated pistons

A special two-cylinder. military specific power plant was employed to evalu ate the effect of thermal barrier coated pistons on overall engine performa nce at simulated low heat rejection-type operating conditions. This study f ocused on three combustion systems including a noncoated baseline ductile i i-an piston along with zirconia and chrome-oxide sealed zirconia coated ana logs. For the test matrix encompassing ten full and half-load operating con ditions, both coated piston combustion systems yielded a detrimental effect on fuel economy in comparison to the baseline combustion system at constan t fueling and air consumption rates. These performance differences were att ributed to a combination of combustion phasing modulations, injection timin g discrepancies, and sluggish combustion associated with the zirconia coate d piston configurations.