Ceramic Material for Thermal Barrier Coatings in Compression Ignition Engine for its Performance Evaluation with Biodiesel

Abstract

In the present investigation, a Dongfeng compression ignition (CI) engine powered by biodiesel and diesel fuel, and analysed to gauge performance when coupled with a Thermal Barrier Coating (TBC) coated combustion chamber. TBC in CI engine improves its thermal retention and enhances biodiesel usability, which has a higher flashpoint than diesel. Biodiesel extracted from non-edible Pongamia Pinnata seeds is blended with diesel in various ratios to prepare 20BD (20%Pongamia Biodiesel + 80%diesel), 50BD and 100BD blends for the experiment. The properties of these fuel blends were tested by following American Standard for Testing and Materials (ASTM) approved testing methods to check their suitability as fuel for the CI engine. The piston crown, cylinder liner, inlet, and exhaust valves surface coated with TBC. The TBC is composed of a bond coat applied on the substrate which needs to be thermally insulated and a topcoat of ceramic material over bond coat. The bond coat of NiCrAl (Nickel-Chromium-Aluminium) of thickness 1 mm and a 4 mm topcoat of Titanium dioxide (TiO2) coated using the plasma spray coating method. A comparative study between a coated and uncoated engine component with diesel and biodiesel blends to study performance effects. The results show that the CI engine with 20BD, consumed 10.6% lower fuel when used in a coated engine than in an uncoated engine. Brake thermal and mechanical efficiency with 20BD were increased by 4.7%, and 2.6% respectively in TBC sprayed CI engine at part load. The lower the heat loss to coolant from the engine, the lower the consumption of fuel. An increase in heat retention in the coated combustion chamber leads to a boost in fuel vaporisation and a shortening of physical ignition delay. Hence, the CI engine's modification to accommodate biodiesel with TBC has a net positive impact on fuel consumption and engine efficiency.