The top portion of the piston is called as a piston crown.
In an engine, the temperature of the piston will be more at the crown of the piston. The piston crown is subject to the high temperatures in the combustion space and the surface is liable to be eroded/burnt away. For this reason, the material from which the crown is made must be able to maintain its strength and resist corrosion at high temperatures.
33) In an engine, the temperature of the piston will be more at the
crown of the piston
Related Automobile Engineering MCQ with Answers
maintains a seal and prevents escape of burned gases and loss of pressure in the combustion chamber
The function of a first compression ring (top ring) is that it maintains a seal and prevents escape of burned gases and loss of pressure in the combustion chamber.
compression ring and aids the top ring in sealing and cooling
The function of a second ring is that it is a compression ring and aids the top ring in sealing and cooling.
prevents engine oil from going into the combustion chamber and returns excess lubricating oil off the cylinder wall through the return holes in the piston to the oil pan
The function of oil control rings is that it prevents engine oil from going into the combustion chamber and returns excess lubricating oil off the cylinder wall through the return holes in the piston to the oil pan.
cast iron
Piston rings are commonly made from cast iron. Cast iron retains the integrity of its original shape under heat, load, and other dynamic forces. Piston rings seal the combustion chamber, conduct heat from the piston to the cylinder wall, and return oil to the crankcase.