The piston is connected to the connecting rod through the piston pin. When the piston moves downward under gas pressure, it transfers the force to the connecting rod. The connecting rod then transmits the force to the crankshaft, causing the crankshaft to rotate. The rotational motion of the crankshaft is the key to the engine’s power output. The reciprocating motion of the piston and the connecting rod and crankshaft work together like a delicate mechanical transmission system to convert the linear power generated by combustion into rotary power to drive the vehicle forward or drive other equipment.

The bottom of the piston the piston ring and the cylinder wall closely match and play the role of sealing the combustion chamber. The piston ring has a gas ring and an oil ring. The gas ring is mainly used to seal the high-temperature and high-pressure gas in the combustion chamber to prevent gas leakage into the crankcase. The main role of the oil ring is to scrape the excess oil on the cylinder wall, but also to assist the gas ring in sealing.

As mentioned earlier, the oil ring can scrape off the excess oil on the cylinder wall during the working process of the piston and make it flow back to the oil sump. This can effectively control the consumption of oil to ensure that the engine works within the normal range of oil.