Experimental Investigation On Performance Enhancement Of A 4 Stroke Petrol Engine Test Rig Using Laser Textured And Tin Coated Piston Rings

Frictional losses at the piston ring–cylinder liner interface account for a significant portion of mechanical losses in internal combustion engines, directly affecting fuel efficiency, emissions, and component durability. Surface engineering techniques such as laser surface texturing (LST) and hard coatings have emerged as effective approaches for mitigating these losses. In the present work, an experimental investigation is carried out on a four‑stroke, four‑cylinder petrol engine test rig to evaluate the combined influence of laser‑textured and titanium nitride (TiN) coated piston rings on engine performance. Two configurations are examined: conventional piston rings and laser‑textured piston rings with TiN coating. Engine performance parameters including brake thermal efficiency, brake specific fuel consumption, and mechanical efficiency are measured under varying engine speeds and loads. The results demonstrate that laser texturing enhances lubricant retention and stabilizes the oil film, while TiN coating improves surface hardness and wear resistance. The combined LST + TiN treated piston rings exhibit the most significant performance improvement, showing reduced frictional losses and enhanced thermal efficiency compared to conventional rings. The study confirms the synergistic potential of surface texturing and TiN coating for improving performance characteristics of petrol engines.