The piston in the cylinder of the cylinder block moves reciprocally by the pressure received when the air-fuel mixture combusts.
The piston ring consists of the compression ring (top ring, second ring) and the oil ring, and has the following functions.
The compression ring prevents leakage of pressure in the cylinder from the piston circumference.
The oil ring clears off extra engine oil adhered to the cylinder wall.
The piston ring transmits piston heat to the cylinder wall to cool the piston.
The reciprocating movement of the piston is transmitted to the connecting rod by the connection of the piston pin to connecting rod.
The high-temperature strength piston is made of aluminum alloy with excellent thermal conductivity.
The piston has a cavity on the top surface. As a result, the initial combustion flame is prevented from hitting the top surface of the piston to reduce cooling loss.
The sliding resistance has been reduced by optimizing the piston skirt shape.
A weight reduction is realized by optimizing the piston shape.
With the adoption of the offset piston, piston slap is suppressed.
A barrel-face ring for the top ring and a taper under cut ring for the second ring have been adopted.
A three-piece oil ring consisting of a side rail and spacer have been adopted for the oil ring.
Tracking capability to the cylinder wall has been improved by thinning down the piston ring. As a result, a low-tension piston ring has been implemented without increasing the engine oil consumption, and the sliding resistance has been reduced during reciprocating movement.
The piston is a full-floating type.