• Increased biodiesel blends, such as B30 and B40, result in decreased engine performance (BTE) and higher smoke, HC and NOx emissions. • The B20 blend is an appealing alternative because it enhances engine performance while lowering emissions. • The country’s economy benefits from the substitution of fossil fuels for indigenous renewable and alternative fuels. • This alternative is more realistic because there are abundant resources of non-edible oil seeds for biodiesel preparation and biodiesel production costs are becoming more affordable. Growing attention in studying renewable and alternate fuels for internal combustion (IC) engines has been increased by concerns about improving engine performance while reducing emissions to satisfy EURO standards and to fulfil increasing energy demands for a growing population. Biodiesels are a possible replacement to diesel fuel since, they are renewable and have qualities similar to fossil diesel. For diesel engines, biodiesel generated from Karanja oil is a better diesel substitute. The use of alternative fuels in a CI (Compression ignition) engine reduces performance while also increasing hydrocarbon (HC) and carbon monoxide (CO) pollutants. However, making the engine entirely adiabatic by combining biodiesel with diesel and applying thermal barrier coatings (TBC) to the piston, cylinder wall, and inlet and outlet valves will improve overall engine performance. In light of this, TBC diesel engine components coated with partly stabilized zirconia (PSZ) and aluminium oxide (Al 2 O 3 ) ceramics were tested in a diesel engine using Karanja oil methyl ester (KOME) and its mixtures. Both diesel and KOME and its blends had their brake thermal efficiency (BTE) emissions measured before and after coating, and the obtained results were matched. Engine performance is nearly comparable with acceptable emission requirements while using B20 powered biodiesel and a PSZ coated engine. Among the biodiesels tested, the maximum BTE was recorded with diesel which was 2.79%, 5.89%, 7.75%, 9.64% and 14.03% greater than B10, B20, B30, B40 and B100 fuel blends. From various fuels tested, the minimum smoke emissions were recorded with diesel which was 6.06%, 12.9%, 20.68%, 29.62% and 39.88% lower than B10, B20, B30, B40 and B100 fuel blends.