Exam Question
Enumerate the causes of Piston Crown burning and subsequent deterioration in engines using Heavy Fuel Oil. Also mention the possible reasons and steps to be taken to correct the situation of complete burn out of the Piston crown.
Class 2 (2nd Engineer)
MEKM
📅 Apr 2019
Reference Answer
Causes of Piston Crown Burning and Deterioration
Stresses on the Piston Due to Gas Pressure: During firing, the piston crown is subjected to both compressive and tensile stresses. The top portion of the crown experiences compressive stress, whereas the bottom surface of the crown is subjected to tensile forces.
Due to Inertia Forces: At Top Dead Centre (TDC), inertia forces tend to cause tensile stresses on the piston surface. At Bottom Dead Centre (BDC), inertia forces combined with the acceleration of the piston subject the surface to compressive stresses.
Thermal Stresses: During combustion, the piston crown is suddenly and cyclically exposed to very high temperatures, resulting in severe thermal stresses.
Stresses on the Piston Due to Gas Pressure: During firing, the piston crown is subjected to both compressive and tensile stresses. The top portion of the crown experiences compressive stress, whereas the bottom surface of the crown is subjected to tensile forces.
Due to Inertia Forces: At Top Dead Centre (TDC), inertia forces tend to cause tensile stresses on the piston surface. At Bottom Dead Centre (BDC), inertia forces combined with the acceleration of the piston subject the surface to compressive stresses.
Thermal Stresses: During combustion, the piston crown is suddenly and cyclically exposed to very high temperatures, resulting in severe thermal stresses.
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