Abstract This study was focused on determining of the effect of insulation level on performance and emission parameters of a turbocharged LHR diesel engine. As first insulation level cylinder head and valves were coated with plasma sprayed yttria stabilized zirconia (Y2O3ZrO2) with a thickness of 0.35mm over a 0.15mm thickness of NiCrAl bond coat (LHR1 engine). At last stage pistons have been coated with the same material and procedure (LHR 2 engine). As the insulation level was increased change in the measured parameter was increased. The results have shown that engine power was increased by 6.6-9.6%, engine torque was increased by 6.9-10%, bsfc was decreased by 4-7.8%, EGT was increased by 13-22%, excess air ratio was decreased by 3-4%, smoke emission was decreased by 10-18% and CO2 emission was increased by 3-6.5%.

Bu çaly?mada motorun yalytym seviyesinin a?yry doldurmaly DIK bir dizel motorunun performans ve emisyonlaryna olan etkilerinin belirlenmesi üzerinde durulmu?tur. Ylk yalytym seviyesi olarak silindir kapa?y ve supaplar plazma sprey yöntemi ile 0,15 mm NiCrAl ba?layycy tabaka üzerine 0,35 mm kalynly?ynda yitriya stabilize zirkonya kaplanmy?tyr (DIK1 motor). Son a?amada ise bunlara ilaveten ayny malzeme ve yöntem ile pistonlar da kaplanmy?tyr (DIK2 motor). Yalytym seviyesi arttykça ölçülen parametrelerdeki de?i?im miktary da artmy?tyr. Sonuç olarak motor gücünün % 6,6-9,6 artty?y, motor torkunun % 6,9-10 artty?y, fren özgül yakyt tüketiminin % 4-7,8 azaldy?y, egzoz gazy sycakly?ynyn % 13-22 artty?y, hava fazlalyk katsayysynyn % 3-4 azaldy?y, duman emisyonunun % 10-18 azaldy?y ve CO2 emisyonunun % 3-6,5 azaldy?y görülmü?tür.