Segmentation (mechanical)

See also: Segmentation

In Mechanical, the segmentation of an Engine spark-ignition has as a function to ensure the sealing of the Piston in the Cylindre.

They are parts made up of an incomplete elastic steel circle, designed to encase itself in throats of the piston. The diameter external at rest is slightly higher than that of the cylinder.

Generally, 3 segments (split rings) are located in top of the piston:

The segment of fire or firebreak, which is closest to the combustion chamber, makes it possible the explosion of the mixture of fuel to print a maximum push with the piston, it stops as its name indicates it the extreme gases and reduces the temperature of the wall of the piston under him.

The ring seal or compression (that of the medium) ensures the complement of sealing of gases of escape passed through the segment of fire. It has the same aspect as the firebreak.

The oil scraper , low, generally in three elements: two very thin rails in top and bottom of a elastic Expandeur perforated, are used to scrape the Huile present on the cylinder under the piston to prevent that it is burned. This oil is projected permanently on the cylinder by the movement of the Bielle S (splash lubrication), by the return of oil of lubrication of the axis of piston or by special jets projecting oil on the piston to cool it.

These parts are very thin and breakable, they are manufactured starting from an elastic steel spring, cut then out of discs constituting the segments. They are generally asymétriques : it is necessary to pay attention within the meaning of assembly during the assembly of the engine.

Space between the two ends of the segment when it is introduced into the cylinder calls the play with the cut . Its measurement makes it possible to evaluate the wear of the segment.

Lubrication