In the combustion chamber of the engine, the energy of rapidly expanding gases is transferred to the piston, then the crankshaft is actuated through the connecting rods. This element of CNG is constantly affected by mechanical, temperature and other loads. The piston feels the force of gas pressure, significantly warms up from contact with fuel combustion products, feels heated as a result of friction against the walls of the cylinders.
We also recommend reading the article about it, what is the piston of an internal combustion engine and how it is arranged. In this article you will learn about the design features of the piston.
Being one of the most loaded elements of the engine, as well as taking into account working conditions, pistons during operation of the internal combustion engine are gradually covered with soot. Accelerated carbon monoxide may occur in this case, if there is any engine malfunction, which leads to violations of the combustion process of the fuel-air mixture in the cylinders. Next we'll talk about that, which may be the cause of soot on the pistons, as well as how to remove soot from the pistons and how to do it.
Where does it come from and what is the scale on the engine piston
If you look inside the engine, can be seen, that over time, many of its details accumulate various deposits. Such deposits are conventionally divided into lacquer formations, soot, sludge. One of the main reasons for the appearance of such deposits is the breakdown of engine oil in the engine. The point is, that the oil has the property of aging, oxidize and decompose. As a result, the decomposition products settle on the parts, forming a layer of sediments.
As for the pistons, soot on them appears as a result, that the fuel in the cylinders does not always burn properly, as well as the fuel contains a large number of additives and impurities. As a result of contact of fuel with the heated piston, cylinder walls, valves and other elements on their surface gradually accumulates a layer of sediment. The intake valve is usually covered with soot, piston crown, combustion chamber walls.
Soot is a deposit, consisting of a zone, and also contain carbon compounds. In other words, inorganic residues, which remain in the cylinder after fuel combustion, various unburned fuel additives, as well as engine oil particles, stable deposits penetrating into the combustion chamber during the operation of the internal combustion engine. This scale in the combustion chamber is also called coke, and its accumulation is called zakokosovkoyu engine. The intensity of coking is affected by the quality of oil and fuel used in the engine, features of operation and serviceability of the motor.
If the quality of oil and fuel is clear, then the oil change intervals have a strong effect on the degree of coking. The better and purer the oil, the less the engine is coked. As for fuel quality, resins are more or less present in it. It should also be considered, that any engine problems, which affect the completeness and efficiency of combustion of the mixture, play a huge role. Example, contaminated injectors affect the quality of fuel spray in the combustion chamber on direct injection engines, wear of piston rings leads to low compression and excess oil into the combustion chamber, non-functioning or defective spark plugs cause ignition failures, Leaking oil as a result of faulty valve seals also allows excess oil to get into the cylinder, etc..
Side surfaces of pistons, grooves for installation of piston rings and walls of cylinders are in addition subject to formation of varnishes on them. Experts note, that soot and varnish, appearing on the upper edge of the piston, contribute to the accelerated wear of the cylinder walls. If the deposits are clogged in the gap, which is between the piston groove and the piston ring, then the latter simply expands.
In this case, a strong pressure is created on the walls of the cylinder, as a result the wall wears out, hon disappears, the cylinder liner is produced, the rings themselves quickly become unusable. In some cases, the walls of the cylinders from Raspertov from the soot rings appeared burrs, it happened and so, that the rings broke, causing damage to cylinder walls and other CNG elements. We will note still, that even if the ring does not burst, deposits still reduce mobility or lead to complete occurrence of the piston rings, that is, these rings are coked. As a result, after loss of mobility compression on cylinders decreases, the engine starts to run intermittently, it starts badly, will overconsume fuel and become covered with soot even more. Excess engine oil begins to enter the combustion chamber, overconsumption of oil begins, remnants of unburned oil heavily contaminate the piston, rings, combustion chamber walls, etc.. It turns out, the problem is only getting worse, and motor coking progresses.
Soot can also be a cause, on which jam the valve in directing plugs, the through-section of inlet and outlet valves is greatly reduced. Sometimes the well-known black scale on the piston can lead to such unpleasant consequences, such as engine detonation or drip ignition, which actually destroys the CHP, leads to local overheating, etc.. Example, the smoldering of the soot in the combustion chamber causes uncontrolled ignition of the fuel (drip ignition), the temperature regime is violated, the petrol power unit may not shut down after the ignition is switched off (diesel). With such an abnormal combustion, the fuel load on the engine increases, which significantly reduces the life of its nodes.
Cleaning of pistons from a deposit without dismantling of the internal combustion engine
Let's start with that, that qualitatively and as much as possible effectively a deposit from the piston and other elements can be removed only by means of manual mechanical cleaning. That means just that, that the power unit needs to be disassembled. Quite obviously, that this method, for all its advantages, is time consuming, costly and quite complex, since not all drivers will immediately agree to disassemble the engine. This is especially true in that case, if the engine is running relatively normally, that is, its repair is not expected in the near future. Also, some owners are trying to remove the scale not as a result of problems, and for prevention.
For this reason, motorists are interested, how to clean the pistons from soot without disassembling the power unit. Note, that such a method exists and is well known. We are talking about decoking the engine and piston rings. The main feature of decoking is the ability to dissolve soot on the pistons. Means for removing scale from the pistons are available, in fact, active solvents, which are filled into the engine through the lubrication system or directly through the spark plugs.
As a result, the pistons are cleaned without the need to disassemble the unit, as it is enough to pour in special means through an oil filler neck or to unscrew spark plugs on the petrol internal combustion engine (spark plugs on diesel). To wash the pistons from soot, you can use two available decoking options. You can clean the engine of coke as quickly and gently as possible (it is enough to buy ready cleaner-decoking for piston rings), and to carry out deep decoking of the motor, which will remove scale not only from the rings, but also from pistons. Similar solutions are available, are products of well-known companies and small manufacturers of car care products. Each of the methods of cleaning one or another composition has its pros and cons, about which we will talk in more detail. We will also answer the questions below, than to clean a deposit on pistons and valves, and in which cases to use different compositions for decoking.
The method of "soft" cleaning of the engine rings
so, the first method of so-called "soft" cleaning should include flushing the engine lubrication system with the effect of decoking piston rings. The products are represented by Liqui Moly brands, Hado and others. This composition is poured directly into the engine oil a couple of hundred kilometers before its replacement. The unit must not be loaded while using the tool, that is, there are some limitations. It is forbidden to spin the engine above average speeds, rides in tension, tow the trailer, to transport goods, etc.. These recommendations are due to, that the additive cleaner affects the properties of the oil, as well as warehouse manufacturers are insured against it, so that the softened deposits from the channels of the lubrication system do not clog the system under high pressure under loads on the internal combustion engine.
As for the composition itself, means for decoking piston rings, usually, wash only oil piston rings. These rings are at the bottom and occur most often. The advantages include the availability of a solution, absence of any additional manipulations, gentle effect on the internal components of the engine, etc.. The disadvantage of this method is that, that it does not allow the removal of soot from the combustion chamber, from the surface of the piston and valves.
For this reason, the decision can be considered purely preventive, as strongly coked motor it will not help any more. In such cases, you can use another method, which is called "hard" decoking of the engine and piston rings.
Removal of soot from the piston and combustion chamber
As you already are, definitely, guessed, this method involves pouring the solvent cleaner directly into the combustion chamber. This method allows you to loosen the soot, after which the deposits burn out during engine operation. Chemicals for such decoking are used more aggressively, and the procedure itself will require some time and a number of specific actions. The most popular remedy today is Lavr cleaner. There is also a group of analogues on the market.
- At the beginning, you need to warm up the engine to operating temperature, on the warmed up engine to unscrew spark plugs or tempering spark plugs (depending on the type of engine).
- Next, the pistons must be set in the engine so, so that they occupy the middle position. To do this, the car must be lifted on a jack (the rear wheel of a rear-wheel drive car rises, on the front-wheel drive car the front wheel rises).
- Then turn on 4 or 5 broadcast, then the engine scrolls by turning the jacked wheel. You can determine the position of the pistons in different ways. The simplest way is to check the location of the pistons with a screwdriver, which is inserted into the combustion chamber through the hole of the spark plug.
- Then through the spark plugs a special composition for decoking is poured into each of the cylinders, then the car can be left, in the middle, on 30 minutes. During this period, the scale begins to soften.
- At the end of the specified period of time should return to the jacked wheel and slightly shake it back and forth (by a few degrees). This is necessary for that, so that the cleaner can leak to the rings to decok them. You can also use the wheel to move the pistons during that, while the soot only softens. Everyone should do this 5-10 wrinkle.
- Now you can move on to the final stage. The task comes down to that, to scroll the engine starter with the spark plugs unscrewed. It is necessary to do it close 15 seconds with transmission on. This operation allows you to remove residual fluid from the cylinders through the spark plugs. If you don't, then at the moment of turning of the engine with the twisted spark plugs the hydraulic shock is possible.
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After the procedure, the candles can be screwed in place and try to start the power unit. You have to be prepared for that, that the motor will not start immediately, as the cleaner will wash away an oil film from walls of cylinders. After starting from the exhaust system may go black thick smoke with a pungent odor, then the motor should be allowed to idle close 15 minutes. Then the car should drive a few kilometers, until the intensity of smoke from the exhaust system decreases.
Then you should either immediately replace the engine oil with fresh, or drive closer 150 km in gentle mode, then the lubricant and oil filter are replaced. It is also advisable to measure the compression before decoking, to then compare the current results. Note, that in some cases the rings after decoking become mobile not immediately, and after 100-200 km.
As a result
To ensure that soot on the pistons and rings does not become a problem, preventive cleaning of the internal combustion engine should be carried out periodically. To do this, you can use the method of "soft" cleaning, which some owners regularly perform before each oil change.
Another effective method of prevention is the accelerated replacement of lubricants, example, each 7-8 thousand. Mileage, and not through the regulatory segment in 15 thousand. It is highly desirable to use high-quality original oils from well-known manufacturers.
Also a sure sign of the formation of a strong deposit on the pistons is the case, when the engine starts to use oil. In this case, the occurrence of piston rings is possible, failure of oil caps, problems with valves, wear of piston rings, etc.. Such problems are factors in themselves, which lead to increased soot formation and coking of the engine. For this reason, experienced motorists are advised not to procrastinate with the diagnosis and repair in that case, if the engine began to consume oil.
Finally, let's add, although it is almost impossible to completely prevent the formation of soot on the pistons, at the same time it is quite possible not to allow that, so that coking and soot lead to engine failure. In other words, the main thing is not to allow a large number of deposits in the combustion chamber, on the piston, valves and other parts. If it happened, use decoking or do mechanical removal of dirt after disassembly of the engine.