Experimental Study of Energy Balance in Thermal Barrier Coated Diesel Engine

Energy conservation and efficiency have been the quest of engineers concerned with internal combustion engine. Approximately one-third of total fuel input energy is converted to useful work. Since the working gas in a practical engine cycle is not exhausted at ambient temperature, a major part of the energy is lost with the exhaust gases. In addition, another major part of energy input is rejected in the form of heat via the cooling system. Recently, much attention has been focused on achieving higher efficiency by reducing energy loss to coolant during the power stroke of the cycle. Thermal barrier coatings have a significant effect in the reduction of wear and abrasion failure in reciprocating and rotary engine for power generation and transportation. As operating temperature increases for improving Brake Thermal Efficiency, the wear and abrasion problem increases and becomes more challenging because lubrication in high temperature locations becomes increasingly problematic. In this study, the effect of insulated heat transfer surfaces on diesel engine energy balance system was investigated. The research engine was a four-stroke, twin cylinder vertical water cooled diesel engine. This engine was tested at different speeds and load conditions without coating. Then, combustion chamber surfaces, piston crown faces, valves, top surface of cylinder head and liners were coated with Partially Stabilized Zirconia (PSZ) attaining low heat rejection condition. Ceramic layers were made of ZrO2 and plasma coated onto base of the NiAl bond coat. The ceramic coated research engine was tested at the same operation conditions as the standard engine. The results indicate reduction in fuel consumption and heat loss to engine cooling system of the ceramic coated engine.