Causes of piston ring fracture, usually the following points. (1) The opening clearance of the piston ring is too small. In the replacement of the piston ring, if the ring is mistaken for the inspection of the open clearance in the upper part where the cylinder wear is the largest, or simply does not boring according to the specified opening clearance value, when the piston ring descends to the smallest part of the wear of the lower part of the cylinder sleeve ( Or due to thermal expansion), the open gap disappears and swells, causing the ring to press against the inner wall of the cylinder liner, resulting in breakage. (2) The clearance between the piston ring and ring groove is too large. After the gap is increased, the piston ring flutters in the groove, which is not conducive to airtightness, and may not cause the inner sea to break due to vibration. The reason why the edge clearance is free from illness is mainly due to the fact that after the cylinder liner wears, the cylinder bore has an unequal internal diameter. In addition to the reciprocating movement of the piston, the piston ring itself performs a one-on-one movement in the ring groove, so that the ring and ring groove Wear on the upper and lower planes worsens. Practice has proved that the wear of the first two grooves on the piston is much faster than that of other grooves. (3) Severe carbon deposits in the ring groove. The coke will cause the groove to be uneven, which will cause the piston ring to undergo alternating bending during operation and will be easily broken. (4) The carbon deposits in the upper part of the cylinder wall form a ring or a step due to wear. In this case, when the piston reaches the top dead center position, the first lane of the fifth stage confuses the impact of this step and causes breakage. Two reasons for the addition are as follows. (1) Coking adhesion. The piston rings are coke-bonded in the ring grooves, and the piston rings are impacted and broken during movement. This is a common cause. (2) The connecting rod is twisted. After replacing the piston ring with a single-cylinder diesel engine, sometimes the diesel engine starts running and several rings are broken. This is mainly due to the twists and turns caused by Xuan Xuan. When the piston goes up, the twisted chain causes the piston ring to be completely broken by a twisting force. After finding this phenomenon, check the rod and correct it. Based on experience and some analysis, I think the main reasons for the piston ring break are the following. (1) The piston ring is divided into two types, the gas ring and the oil ring. The first gas ring is broken. Although the first gas ring is chrome-plated, it is still worn more seriously than other rings because it is in a worse working environment than other environments. This is one of the reasons why the first gas ring is easily broken. (2) Piston ring opening clearance, edge clearance, or backlash is too small. When the ring expands, it is easily broken due to card issuing. (3) The oil supply time is too early, the diesel engine knocks, the temperature of the engine increases, and the amount of coke increases, causing premature wear and breakage of the piston ring. (4) When the connecting rod is bent or distorted, and the connecting rod small head copper bushing is improperly assembled or milled, the piston connecting rod group may unevenly wear or even break the piston ring due to uneven force during movement. (5) If the engine temperature is too high, the piston ring may stick or stick to the cylinder. When operating, the piston ring may be easily broken. (6) Piston rings are generally cast from grey cast iron and alloys. Casting defects can also easily cause breakage of the piston rings. From the current actual situation, the common causes of piston ring breakage are as follows. (1) The piston ring is of poor quality. (2) The piston ring opening clearance is too small. (3) After the old cylinder is replaced with a new ring, the first air ring hits the cylinder sleeve shoulder. (4) The ring opening of the piston expands too much during assembly. (5) Severe carbon deposit in the cylinder. Two examples of piston ring breaking are given below. (1) An S195 diesel engine was overheated due to lack of water during operation, and the engine was immediately shut down and extinguished. The standby temperature was lowered and cooling water was added. The crankshaft was shaken, and the first piston ring was dismantled. Broken. This is because when the engine is overheated, the flameout is too rapid and the piston ring sticks. The correct approach should be to make the engine idling for a while, turning off the standby temperature and then turning off. Shake the crankshaft immediately after the flame is turned off until the machine temperature is reduced again. (2) A S195 diesel engine was difficult to start due to excessive wear of the piston ring, and started smoothly after replacing the new ring. However, after working for a period of time, the engine was automatically shut off and the piston ring was broken. The last finding was that the gap in the opening of the piston ring was too small and it was stuck after thermal expansion.
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