All current automobiles feature three
piston rings per piston.
Located in the first ring groove which has the primary function of sealing the combustion gases and transferring heat from the piston to the cylinder wall.
Sometimes called the scraper ring is located in the second ring groove which has dual-purpose of assisting the top ring and also control the amount of oil so that the top ring has enough lubrication.
Can be one-piece or three pieces, the oil rings control the amount of lubricating oil passing up or down the cylinder walls and prevent the oil from passing between the face of the ring and the cylinder through the gap.
