What are the important functions of the piston ring of the diesel generator set?

The piston ring is a metal elastic ring with a large outward expansion deformation. It is widely used in various power machinery and is the core component of the diesel generator set. It is assembled into the cross-section and its corresponding annular groove. It can be divided into gas ring and oil ring. The four important functions of piston ring include heat transfer, oil control, support, and air tightness.

Diesel generator set piston ring

 

       The piston ring is a metal elastic ring with a large outward expansion deformation. It is widely used in various power machinery and is the core component of the diesel generator set. It is assembled into the cross-section and its corresponding annular groove. It can be divided into gas ring and oil ring. The four important functions of piston ring include heat transfer, oil control, support, and air tightness.

 

       1. Heat transfer

       The piston of an internal combustion engine works under the action of high temperature and high pressure gas in each burst. Therefore, if the heat from the top of the piston is not dissipated and cooled in time, the top of the piston will overheat severely. As a result, scratches due to abnormal expansion of the piston, early wear of the piston due to reduced hardness, sticking rings due to oil deterioration, damage due to reduced strength at the piston crown and piston pin seat, etc. These all bring fatal danger to the normal operation of the engine. It can be seen that the function of the piston ring includes transferring the high temperature of the piston caused by the combustion gas to the cylinder, that is, cooling the piston. According to relevant information, 70%-80% of the heat in the atmosphere at the top of the piston is dissipated through the piston to the cylinder wall.

       2. Control oil

       The piston ring slides back and forth along the cylinder wall under high load and high temperature atmosphere. In order to play its function better, it is necessary to have a small amount of oil to lubricate the cylinder and piston, and must properly scrape off the excess oil attached to the cylinder wall to prevent it from running up to keep the oil consumption moderate. In order to control the oil running up, the outer circle of the second air ring on the piston is generally made into a conical surface. The conical ring can not only lay an oil film on the sliding surface of the piston when the piston goes up, but also effectively scrape off the excess oil at the lower end of the cylinder wall when the piston ring goes down, which really kills two birds with one stone. The characteristic of this kind of ring is only that its contact pressure is high, and because the upper and lower scrapers can act separately, it has good adaptability even for cylinders with poor roundness. More importantly, each scraper not only maintains a seal with the sliding position between the cylinders, but also maintains an airtight effect on the oil between the upper and lower ends of the ring groove, so the oil sealing effect is excellent.

       3. Supporting role

       The piston reciprocates due to gas pressure, and this reciprocating motion is transformed into rotational motion through the crankshaft, so the piston ring bears the side thrust component. Therefore, the piston ring fills the gap between the piston and the cylinder, and often makes sliding movement in contact with the cylinder wall. Not only does it prevent blow-by and control the oil, but it also prevents strong contact between the piston and the cylinder wall. The high pressure gas also reaches the back gap of the ring, and its pressure presses the outer circle of the piston ring against the inner wall of the cylinder, so that the piston keeps the floating state. It can be considered that at this time, the piston ring and the ring groove must have suitable backlash and backlash. In general, the backlash has two functions: the first is to prevent the ring from sticking in the groove due to the expansion of the piston ring and the piston; the second is to increase the contact pressure of the sliding surface of the piston ring. It plays a role in preventing the strong contact between the piston and the cylinder wall.

       Fourth, maintain air tightness

       An important role of the piston ring is to maintain the seal between the piston and the cylinder wall and to control the leakage to a minimum. This role is mainly undertaken by the gas ring, that is, under any operating conditions of the engine, the leakage of compressed air and gas should be controlled to a minimum to improve thermal efficiency; to prevent the leakage between the cylinder and the piston or between the cylinder and the ring. Seize; prevent failure caused by deterioration of lubricating oil, etc.

 

       The above is the introduction of the function of the piston ring of the diesel generator set. It is worth noting that the piston ring of the diesel generator set loses its sealing function faster than the cylinder liner wears to the limit value due to wear. Therefore, the user is operating the diesel generator set. When it happens, always pay attention to the state of the piston ring and deal with it in time.