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In Internal Combustion (I.C.) engines, seat inserts and valves are the major components responsible for performance, emissions and reliability. Failure of these components can cause performance deterioration. In case of compressed natural gas (CNG) engines, impact on life of seat inserts and valves are adversely affected due to its dry combustion environment and high operating temperatures. Greaves cotton has developed a single cylinder, water cooled, dedicated CNG engine with port injection from the base diesel engine. Major challenges were encountered during the CNG engine development with respect to seat inserts and valves wear. The design was modified considering the different design parameters to arrest failure modes as given below: 1 Seat insert material compatibility 2 Seat angle 3 Seat width 4 Valve head stiffness 5 Alignment of seat inserts and valves 6 Valves closing velocities.

High vibration stimulus is a characteristic of single cylinder diesel engines. The load carrier segment driven by single cylinder diesel engine operates on low running speeds and heavy load. This operating condition pushes the vibrations generated in the engine to extreme level making it challenging to design peripheral components. More-over, simulation of components involving welded joints becomes further more challenging as virtual representation of welded joint and prediction of its behaviour under high vibrations is difficult to model. Also, the behaviour of over-all design changes drastically when the position and orientation of welding seam is altered. Different weld seam positions under high vibration input may lead to varied mechanisms of weld seam opening and it changes the stress distribution on the mating component leading to different mechanics of failure.