How to identification if a piston ring is of good quality?

The working surface of the Piston Ring shall not have nicks, scratches, peeling, the outer cylinder and the upper and lower end surfaces shall have a fixed finish, the curvature deviation shall not be greater than 0.02-0.04 mm, the standard subsidence of the ring in the groove shall not exceed 0.15-0.25 mm, and the elasticity and clearance of the piston ring meet the requirements. In addition, we should also check the light leakage of the piston ring, that is, the piston ring is flat in the cylinder, put a small lamp under the piston ring, put a light screen above, and then observe the light leakage gap between the piston ring and the cylinder wall, which shows whether the contact between the piston ring and the cylinder wall is good.

Under normal circumstances, the light leak seam of the piston ring measured with a thickness gauge should not exceed 0.03 mm. The length of continuous light leakage seam should not be greater than 1/3 of the cylinder diameter, the length of a number of light leakage gaps should not be greater than 1/3 of the cylinder diameter, and the total length of a number of light leakage should not exceed 1/2 of the cylinder diameter, otherwise, it should be replaced.

The piston ring is a metal sealing ring with certain elasticity, which is assembled in the piston ring groove and seals the cylinder together with the piston.

The piston ring is affected by the high temperature and high pressure gas in the cylinder when working, and the high-speed movement in the cylinder under difficult conditions of lubrication, especially the temperature of the first ring can be as high as 600K, therefore, the piston ring is one of the parts with the worst working environment and the shortest service life in the engine. In order to extend the service life of the piston ring and ensure its reliable work, the material used for manufacturing the piston ring should have good wear resistance, heat resistance and thermal conductivity, while having sufficient strength, elasticity and impact toughness.

The piston ring is the core part of the engine, and there are two kinds of gas ring and oil ring respectively.

The gas ring mainly plays the role of sealing and preventing air leakage of the cylinder, followed by the heat transmitted from the top of the piston to the cylinder liner, and then the heat is taken away by the cooling water. The oil ring itself can store some of the oil, which is used to lubricate the Cylinder Liner, and can also scrape the excess oil from the cylinder liner. If the piston ring is damaged, the power of the engine will decrease, and it will cause oil deterioration. The piston may also be in direct contact with the cylinder wall, causing the cylinder to knock, which shows the importance of the piston ring to the car. Generally, as long as the exhaust gas emitted by the car is blue, it can basically be judged that the piston ring is faulty.

Precautions (should be noted when installing the piston ring)

1) The piston ring is flat into the cylinder liner, and there should be a certain opening gap at the interface.

2) The piston ring should be installed on the piston, and in the ring groove, there should be a certain side gap along the height direction.

3) The chrome ring should be installed in the first line, and the opening should not be in the direction of the vortex pit on the top of the piston.

4) Each piston ring opening staggered 120 ° C, are not allowed to face the piston pin hole.

5) Cone section piston ring, the cone should be upward when installing.

6) When the general torsion ring is installed, the chamfer or groove should be upward; Keep the cone facing upward when the cone reverse torsion ring is installed.

7) When installing the combined ring, the axial lining ring should be installed first, and then the flat ring and the waveform ring. A flat ring is installed on the top and bottom of the waveform ring, and the opening of each ring should be staggered.

The piston ring is a kind of metal elastic ring with large outward expansion deformation, which is assembled in the profile and its corresponding annular groove. Reciprocating and rotating piston rings rely on the pressure difference of gas or liquid to form a seal between the outer circle of the ring and the cylinder and one side of the ring and the ring groove.