Piston rings are made with metals and are called split-type rings. They are configured in grooves in the external piston diameter. They provide a good seal for the cylinder wall and piston. Piston rings are made based on their applications and functions. The base of their uses is that there are 3 main types and main operations of pistons: to seal combustion, either for a 2-stroke or 4-stroke engine.
The piston rings are the main components of the piston. They use it for the engine based on type and capacity. In this post we will cover different features and types of piston rings. So let’s get started with an introduction to piston rings.
Composition of Piston Rings Made
- The cast iron is a very commonly used material for the creation of piston rings. With that, some alloys used are nickel, copper, chromium, and molybdenum.
- The main feature of cast iron is self-lubrication, which is due to graphite, so it is used for piston rings.
- For increasing the working life of piston rings, use such rigid materials.
- Pressed steel is also used for making piston rings.
Piston Ring Coating
- Piston rings work in different loading conditions and high temperatures that affect the piston to wear out. To minimize that effect, rings are coated with different coatings.
- Iron oxide, phosphate, and graphite are used for ring coatings since they have a soft nature. With that, they also provide good oil-absorbing features.
- Some other features of these materials are that they avoid ring scuffing, which occurs when a metal-to-metal connection is made for high temperatures.
Functions of the Piston Rings?
The basic working of piston rings is as
Seal for Combustion Gas
- This working function of piston rings provides airtight features in the cylinder, such as between the piston and the cylinder wall. As a result, it saves combustion gas leaking from the piston and cylinder due to the gap resulting from the explosion.
- If there is combustion gas leaking, the engine does not detect complete power and causes the use of high fuel. That affects the environment and increases costs.
Control Lubrication Oil
- This feature is used for keeping fewer lubricating oil layers that avoid burns. The inner side of the engine cylinder, piston rings, faces high-temperature combustion gas that is produced many times in a single minute.
- So the use of piston rings helps the cylinder and piston ring not burn and lubricating oil not go to the inner side of the combustion chamber. So there is a need to keep the lubricating oil layer in the cylinder wall at a low level.
Heat Conduction
- The other function of the piston ring is to remove heat from the piston towards the cylinder. If gas exploded in the combustion chamber, the temperature could be high, about 300 degrees. That high heat causes chances of engine damage. So it releases heat for that purpose, the piston ring used.
Main Types of Piston Rings
Compression Rings
- Normally 2 or 3 compression rings exist on the piston. The use of rings is based on compression. The 2nd and 3rd rings are taper-designed. That helps prevent ring-sticking problems for high-power engines.
- For upper and 2nd compression rings, scrapping rings and counterbores are used. These rings cause twisting at the time of the suction stroke. It occurs as a result of inner forces generated through cutting the corner rings.
- At the time of the compression stroke, the rings move upward when the piston moves in an upward direction. During that process, it causes a stake on oil film in the cylinder wall. That minimizes oil given to the combustion chamber.
- For power stroke pressure applied due to combustion that unwinds rings. That makes a complete connection between cylinder walls and sealing.
Wiper Ring
- The wiper ring, also known as the Napier ring, is connected below the compression ring. Their main work is to clean the liner surface from extra oil and work as a backup support ring for preventing any gas leakage that normally occurs at the upper part of the compression ring.
- Mostly wiper rings come with a taper angle design that is configured toward the lower part for the wiping process when the piston moves toward the crankshaft.
- If the wiper ring is not accurately connected with the tapered angle that is close to the value of the compression ring, it causes high oil use. That is resolved through the wiper ring removing extra oil to the combustion chamber.
Oil Control Rings
- The inner side of the connecting rod spoils oil in engines due to revolution of oil pan. As a result, more oil reaches the cylinder as compared to the required value.
- This extra oil should be off and then turned to the oil pan, and then it will move to the combustion chamber and get burned. It causes high oil combustion, and the engine needs oil filling frequently.
- So the oil-removing process is important for cooling, clearing, and sealing in cylinder walls.
- Oils also come with subtypes that are.
- The first one is a one-piece slotted cast iron, and this cylinder has slots between the lower and top sides of the cylinder. The expander spring is used to high-pressure the ring on the cylinder wall. It provides a high scrapping effect.
- The other type of one-piece pressed steel rings are used for engine-worn cylinder walls.
- Third type of 3-piece steel with expander, that is sealed from both upward and downward sides. It is an effective seal.
What do piston rings do?
- Stock automotive pistons come with 3 rings. The upper and middle are used for pressing strongly from the cylinder wall and sealing the combustion chamber that retains combustion gas in and oil on the outer side.
- The lower or oil rings scrape oil off the cylinder wall down to the cylinder, back depositing it into the oil sump. Due to the highly thin film of oil lubricating the ring’s wall, it is normal for some oil to burn at the time of combustion.
Signs of Bad Piston Rings
Exhaust Smoke Discoloration
- The bad piston rings are found through color changes of exhaust. The engine of the moving car releases thin, white-colored smoke from the exhaust. But when piston rings wear, the color with the density of exhaust smoke varies. It can be thick with a dark greyish color and produces a burning smell.
- If the partition between oil and fuel mix affects causes piston ring damage. So when engine oil goes to the combustion chamber, it affects the balance of fuel and air. So make an affected combustion process that causes discolored smoke.
High Oil Consumption
- high oil combustion occurs in the engine in result when oil becomes dirty and now needs to be replaced. Simply, there is no oil burning for 5000 to 15000 Km. Damaging piston rings a common cause for high oil use. Check below your car for oil drops. To avoid high oil use do proper inspection of the combustion chamber and piston rings.
Bad engine performance
- Bad piston rings also involved the bad engine working performance. The not working engine is easy to detect at the time of driving or driving also can assess. If the engine is not working well, it causes vehicles to shudder, stutter, and also causes stalls.
Low acceleration
- This sign is part of the engine working performance. The engine causes low acceleration as a result of a shudder. The low acceleration causes the car not to move with speed and uniformly.
- The vehicle with bad acceleration performance faces difficulty pulling up hills. Either it is a bad sign of a piston ring, but not a serious cause that can be easy to managed. If you change the pistons, solve this issue.
Oil in the intake manifold
- In the engine bay, there is a small filter where the intake pulls in air. That air mixture with fuel in the combustion cylinder causes the engine to run. The fuel does not ignite without air, and the engine does not start.
- If combustion occurs, it affects piston rings. It causes oil to go back in the intake manifold. That process is called blow by. The identification of blow-by is made through an oily layer in the intake or oil drops on the air filter.
FAQs
Can we drive with bad piston rings?
- It is not suggested to drive a car with affected piston rings for a longer time. The longer time issue occurrence causes high damage for you. It not only affects the car engine but also increases the chance of an accident.
Is it always necessary to replace piston rings?
- The complete change of piston rings is not always needed if some parts are damaged. Such as there are many engine components that exist that can increase piston ring sealing and minimize oil use. It is short of works but not for a longer time.
Which piston ring controls combustion pressure to apply on the crankcase?
- The piston normally comes with 3 rings: two top compression rings and one oil ring at the lower part. The compression ring controls blow-by, and oil rings stop oil from entering the combustion chamber.
Which piston ring lies in the center of the engine?
- The compression ring exists in the ring groove close to the piston head. The compression ring seals the combustion chamber from leakage at the time of the combustion process.
Which tool is good for measuring piston ring end gap & valve clearance?
- The feeler gauge is best to use for measuring valve clearance and also for ring joint clearance on piston rings.
What happens when piston rings go bad?
- The bad engine affects the engine power. It also reduces compression so the engine faces difficulty moving. If there is throttle used and waiting for a longer time to increase engine speed, it means your piston ring is not working well.
What are the functions of piston rings?
- The main working of piston rings in an engine is to seal the combustion chamber so less gas is lost. It helps to increase heat transfer from the piston to the cylinder wall.
- It also maintains a quantity of oil between the piston and the cylinder wall.
What are the 5 parts of a piston?
- The main parts of the piston are the piston head, skirt, ring grooves, ring lands, piston pin bore, piston pin, and piston rings.
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