1. The document experimentally investigates the performance and emission characteristics of a diesel engine with mullite ceramic coating. 2. Testing found that the mullite thermal barrier coating improved the engine's brake thermal efficiency by up to 5.78% and reduced specific fuel consumption by 5.46% compared to the uncoated engine. Emissions such as smoke and CO were also reduced. 3. The mullite coating provides thermal insulation which increases in-cylinder temperatures and aids combustion, improving performance and reducing some emissions while increasing NOx emissions by around 4%. The coating demonstrates potential as an alternative to conventional yttria stabilized zirconia thermal barrier coatings.