How The Engine Piston Ring The Engine

- Aug 15, 2017 -

How the engine Piston Ring the engine
Piston Ring at work, due to high temperature, poor lubrication conditions, the wear and tear failure is often faster than the cylinder wear limit speed. As the Piston Ring wears, the spring force of the Piston Ring will gradually weaken, the end gap, the backlash increases, will make the sealing performance worse, resulting in high pressure gas channeling and lubricating oil channeling phenomenon, reduce the engine power and Economy.
    Piston Ring in addition to wear failure, there is a common fracture damage. As the Piston Ring brittle, if the installation method inappropriate, or Piston Ring backlash, the end of the slot is too small and the engine burst, heavy load impact will cause the Piston Ring fracture. Therefore, the Piston Ring should be properly selected and installed.
    1. Piston Ring matching
    Piston Ring matching requirements are: with the cylinder, piston repair size consistent with the provisions of the elastic to ensure that the cylinder seal; ring leakage, the end of the gap, backlash, backlash should meet the design requirements.
    (1) OD size
    The Piston Ring has the same size as the cylinder, the piston to increase the size of the repair to meet the needs of the engine repair. Engine cylinder wear is not large, should be selected with the cylinder at the same level of the Piston Ring. When the engine overhaul, should be in accordance with the repair size of the cylinder, with the cylinder, piston with the same repair level Piston Ring.
    (2) elasticity
    Piston Ring elasticity is the establishment of the back pressure of the primary conditions, but also to ensure that the necessary conditions for the sealing of the cylinder. Elasticity of the ring wear more intense; elasticity is too weak, the cylinder seal performance is poor, fuel consumption increases, coke serious.
    (3) Leakage of the new Piston Ring and cylinder wall before running, the outer surface of the ring can not be fully fit with the cylinder wall, not fit with the cylinder wall to form a gap, the gap can be tested by the light, said For the light leakage test.
    Piston Ring leakage photometric test of the general technical requirements are:
    ① the same ring on the light leakage is not greater than two, each missed arc length corresponding to the sum of the central angle of not more than 45 degrees.
    ② the Piston Ring openings at both ends of the 30-degree range is not allowed to leak.
    ③ the maximum gap leakage is not greater than 0.03 mm.
    (4) inspection of end warpage
    The end face of the Piston Ring and the upper and lower end faces of the Piston Ring groove are the second sealing surface of the ring. This sealing surface is not good, will cause leakage. Therefore, the flatness of the Piston Ring end face should be checked. There are two kinds of test methods: a special equipment to test, that is, the use of surface roughness is very small two parallel plate, the distance between the thickness of the ring to be tested plus 0.05 mm to allow warping range, when the detection ring can be unimpeded Pass this interval to indicate qualified. The other is a simple method, the ring freely flat on the plate, observe the contact situation or the plane light leakage, decide whether to adopt.
    (5) Piston Ring clearance check
    The stub is the gap (also known as "open gap") where the Piston Ring is placed in the cylinder and present at the opening of the ring. The end gap prevents the Piston Ring from being thermally expanded and stuck in the cylinder. The size of the end gap and the diameter of the cylinder and the temperature of each ring, generally every 100 mm bore, the highest temperature of the first ring of the end of the gap is 0.25 ~ 0.45 mm, the rest of the ring temperature is low, the end of 0.20 ~ 0.40 mm.
    To check the Piston Ring end clearance, first place the Piston Ring flat in the cylinder to be fitted, push the Piston Ring flat with the piston head (push the unprocessed cylinder to the minimum wear), then insert it with the thickness gauge Piston Ring opening for measurement.
    (6) test of the Piston Ring backlash
    The backlash of the Piston Ring is the clearance between the piston end face and the Piston Ring groove after the plunger is inserted. The backlash is too large, will make the Piston Ring pump oil exacerbated, the ring easy fatigue broken, accelerated ring rupture and lubricating oil consumption increased; backlash is too small, will make the Piston Ring stuck in the ring groove, Weakened, the impact of stress increased, not only to reduce the performance of the cylinder seal, but also easy to ring. The measurement method is to put the ring in the tank, rolling around the slot for a week, should be able to free rolling, neither loose, and can not have a block phenomenon.