The Purpose of Piston Rings In Engines

What are piston rings

The piston rings are embedded in the piston groove and is a key component of the fuel engine. It can ensure the sealing effect of the engine and prevent fuel gas leakage, which has a great impact on engine performance.

Piston rings are divided into two types: gas rings and oil rings. The role of the gas ring is to ensure the seal between the piston and the cylinder, and is used to seal the compressed air in the combustion chamber; the oil ring is used to scrape excess oil on the cylinder to prevent oil from escaping. into the cylinder for combustion.

Therefore, although piston rings are small, they play an important role in ensuring the normal operation of the engine.

The purpose of piston rings in engines

1. Sealing: refers to sealing the gas to prevent the gas in the combustion chamber from leaking into the crankcase, minimizing gas leakage and improving thermal efficiency. Air leakage will not only reduce the power of the engine, but also cause the engine oil to deteriorate.

2. Oil adjustment (oil control): Scrape off excess lubricating oil on the cylinder wall, and at the same time create a thin oil film on the cylinder wall to ensure normal lubrication of the cylinder, piston and piston rings. In modern high-speed engines, special attention is paid to the role of piston rings in controlling the oil film.

3. Heat conduction: The piston rings conducts the heat of the piston to the cylinder liner, which plays a cooling role. 70~80% of the heat received by the top of the uncooled piston is transferred to the cylinder wall through the piston rings, and 30~40% of the heat received by the cooled piston is transferred to the cylinder wall through the piston rings.

4. Support: The piston ring keeps the piston in the cylinder, prevents the piston from directly contacting the cylinder wall, ensures smooth piston movement, reduces frictional resistance, and prevents the piston from knocking on the cylinder. Generally, the piston of a gasoline engine uses two gas rings and one oil ring, while a diesel engine usually uses two gas rings and one oil ring.

Functions of gas ring and oil ring

The piston ring is a component of the piston connecting rod group of the crank connecting rod mechanism of the automobile engine. It is divided into two types: gas ring and oil ring. Generally, each cylinder has two gas rings and one oil ring. Some engines have three gas rings, an oil ring.

1. The main function of the gas ring is sealing and heat transfer:
Sealing refers to ensuring a good seal between the piston and the cylinder wall, preventing the combustible mixture and high-temperature gas in the cylinder from leaking into the crankcase, ensuring that the combustible mixture entering the engine is sufficiently compressed, and reducing pressure leakage during the power stroke.

Heat transfer mainly refers to transferring the heat received by the top of the piston to the cylinder wall to prevent the piston from overheating. Generally speaking, 70%-80% of the heat at the top of the piston is conducted to the cylinder wall through the gas ring.

2. The main function of the oil ring is to scrape off the excess oil splashed on the cylinder wall when going down to prevent excess oil from entering the combustion chamber and participating in combustion; when going up, it spreads a uniform oil film on the cylinder wall to prevent it from entering the combustion chamber. Reduces wear on pistons, piston rings and cylinders.

Conclusion

Piston rings are widely used in various power machinery, such as steam engines, diesel engines, gasoline engines, compressors, hydraulic presses, etc. Generally, the piston ring is installed in the ring groove of the piston and is the core component inside the fuel engine. It completes the sealing of fuel gas together with the cylinder, piston, cylinder wall and other components.