What is a piston ring
A piston ring is a split ring that fits into a groove on the outer
diameter of a piston in a reciprocating engine such as aninternal
combustion engine or steam engine.
Most automotive pistons have three rings: The top two while also
controlling oil are primarily for compression sealing (compression
rings); the lower ring is for controlling the supply of oil to the
liner which lubricates the piston skirt and the compression rings
(oil control rings). At least two piston rings are found on most
piston and cylinder combination. Typical compression ring designs
will have an essentially rectangular cross section or a keystone
(right angled trapezoidal) cross section. The periphery will then
have either a barrel profile (top compression rings) or a taper
napier form (second compression rings or scraper rings). There are
some taper faced top rings and on some old engines simple plain
faced rings were used.
Lubrication of piston rings is difficult and has been a driving
force to improvements in the quality of motor oil. The oil must
survive high temperatures and harsh conditions with a high-speed
sliding contact. Lubrication is particularly difficult as the rings
have an oscillating motion rather than continuous rotation, as for
a bearing journal. At the limits of piston movement, the ring stops
and reverses direction. This disrupts the normal oil wedge effect
of a hydrodynamic bearing, leading to pronounced wear and the
formation of a 'step' in the cylinder bore around the height of the
upper ring. Noting that some sleeve valve engines suffered far less
from such wear, complex designs such as a rotating cylinder liner
have been considered, just to address this problem.
Piston Rings critical quality
The piston might be a fairly loose fit in the cylinder. If it were
a tight fit, it would expand as it got hot and might stick tight in
the cylinder. If a piston sticks (seizes) it could cause serious
damage to the engine. On the other hand, if there is too much
clearance between the piston and cylinder walls, much of the
pressure from the burning gasoline vapour will leak past the piston
(a condition known as blow-by) and into the crankcase, and the push
on the piston from combustion will be much less effective in
delivering power.
Maojia Industry’s piston rings advantages
1. Years of OEM experience in China and overseas.
2. High quality material and superior steel.
3. Specification perfectly match different engine.
4. Experienced engineers and technical team.
5. Advanced manufacturing equipment, R&D software and test
machine.
6. 100% tested for size and performance before shipment.
7. Global market acceptance.
