It is estimated that this article will move a lot of people's cheese, so after writing it, I have been hesitant to send it out. Later, Lao Hou gritted his teeth and stomped his feet and decided to release it. Anyway, Lao Hou is selfless and wide in his heart, this is my point of view, not for anyone, not for any brand, just on the matter. Maybe my views are biased and not necessarily absolutely correct, but this is my true expression. If you have a different view, please feel free to discuss it in the comment area or private message. However, refuse to personally attack and slander and insult, and all those who have this behavior will be reported + blocked by Lao Hou.
A few days ago I wrote an article "Popular Science: How Does Carbon Deposit trap the piston and cause the engine to burn oil?" It says that ordinary no-use cleaning methods cannot clean the carbon deposits on the piston rings. After the article was sent, some people approved and some people opposed. I can't fully express my views in the comment area, so I simply write another article to express my understanding of engine carbon deposits and my understanding of various carbon deposit cleaning methods. First of all, the conclusion: most of the engine carbon deposition does not need to be cleaned, and when it is necessary to clean the carbon deposit, the non-demolition cleaning can no longer be solved.
The word engine carbon deposition the majority of car owners and friends have heard the ears out of the cocoon, as long as your car has cold start difficulties, engine shaking, lack of power and other phenomena, go to the repair shop, 4s shop, etc., the first step is to remove the carbon deposit for you. Washing throttle valves, washing intake ducts, washing valves, washing combustion chambers, washing ternary, washing oil injectors, etc., and even washing superchargers; playing hanging bottles, walnut sand, dry ice, cleaning agents, adding diesel to the oil, etc., all kinds of soil methods, foreign methods are used for you. A "big wash" came down, and thousands of ocean flowers went out.
Does it work? Definitely! The engine may no longer shake, and the power of the car has recovered.
Is it the credit for cleaning the carbon deposits? Not all! Not all carbon deposits will affect the performance of the engine, only a few parts of the carbon deposit will have an impact on the engine, as long as these positions are finally cleaned, the carbon deposition is removed, the effect is natural. It's like a few years ago media reported that a certain fuse of the car was broken, resulting in the engine can not start, the repairman knows where the fault point is, but still did a large inspection, changed several parts, and finally replaced the fuse. The fault is indeed ruled out and the engine can start, but can you say that the credit for replacing these parts is credited?
The so-called engine carbon deposition refers to the engine in the process of work, the oil and fuel in the unsaturated olefins and colloids, etc., in the high temperature state after a series of physical and chemical changes, the final coking, curing, and then deposited in the engine internal positions, such as throttle, intake manifold, injector nozzle, inlet, exhaust valve back, combustion chamber wall, piston, three-way catalyst, etc., after a period of time, the formation of a black scorched substance, people called "carbon deposition".
It should be noted that carbon deposition is not the pure "carbon" in chemical elements, but a compound, generally spongy, with certain oil absorption characteristics. The black powdery substance we feel in the exhaust pipe is the real "carbon", which is generated because the fuel is not completely burned. When we open the valve chamber cover, the oil pan, and the yellow-brown gelatinous substances seen on the engine cylinder block wall and on the cylinder head and camshaft, they are not carbon deposits, but sludge, which are formed by the gel deposition in the oil.
There is also the fact that no matter what type of internal combustion engine, as long as it uses fossil fuels, carbon deposits will be generated, which is an inherent property of the internal combustion engine, and no technology can completely prevent the formation of carbon deposits. So we don't have to see carbon deposits as a flood of beasts, we have to go and go quickly. Generally, mild carbon deposition does not affect the normal use of the car, and only when there is serious carbon deposition will it affect the performance of the engine.
Let's analyze the formation mechanism of carbon deposits in specific parts and the impact on the engine, and then analyze whether various non-demolition carbon cleaning methods can clean these carbon deposits. Here we do not discuss whether various cleaning agents are effective for carbon deposits, but only whether they are physically accessible.
1. Throttle carbon deposition
Throttles are engine intake channels, and throttle carbon deposits are deposited from residual fuel vapor and oil vapor in the intake pipe. It is deposited on the inner wall of the throttle and on the throttle flap, which will lead to a decrease in the amount of air intake in the engine, which in turn will lead to engine idle jitter, low speed weakness, slow acceleration and so on. This part of the carbon deposit is serious, generally the oil or fuel quality is not good, or the air quality is poor, the dust is larger, or the air filter quality is poor, and the dust in the air is not well filtered out.
The carbon deposits in this part can only be removed by manual dismantling and washing, and other cleaning agents, walnut sand, dry ice, hanging bottles and other methods cannot physically touch this position. The cleaning method is very simple, we can operate it ourselves, remove the intake pipe, expose the throttle valve, and then use the throttle cleaner to erase the carbon deposit on the inner wall and flap. It is not necessary to remove the entire throttle or spray heavily with detergent. The only thing that affects the performance of the engine is the carbon deposit on the inner wall of the throttle and the edge of the flap, and the carbon deposit in other parts has no effect on the engine.
In addition, the cleaning principle of throttle carbon deposition is "no fault and no cleaning", which is a maintenance project rather than a maintenance project, if the engine does not have a failure such as idle jitter, it does not need to be cleaned. Do not wash the throttle frequently, otherwise it will damage the special coating on the inner wall of the throttle, resulting in more and more serious carbon deposition of the throttle, and will also lead to throttle shaft jamming, which will eventually lead to throttle damage.
2. Carbon deposition in the intake tract
Inlet carbon deposition is also deposited by residual fuel vapor and engine oil vapor in the intake pipe, but the temperature of this part is relatively low, so carbon deposition is generally not very serious. For manifold injection engines, due to the cleaning effect of fuel, the intake tract rarely has serious carbon deposition; for the engine with direct injection in the cylinder, there will be a very small number of models with serious intake tract carbon deposition. Severe inlet carbon deposits can hinder the flow of air, narrow the intake passage, absorb fuel, and reduce engine dynamics.
If it is a slight inlet carbon deposit, we don't have to pay any attention to it, it will not affect any performance of the engine. If it is a serious inlet tract carbon deposition, it can only be completed by disassembling and cleaning methods, and other cleaning agents, walnut sand, dry ice and other methods cannot physically touch this position; the hanging bottle can fill the intake tract with cleaning agent, but the carbon deposit that can be cleaned down is minimal.
In addition, if there is a serious carbon deposit in the intake tract, there must be a problem with the quality of the fuel or oil, and the colloidal content of the two is too high; or there is a problem with the forced ventilation system of the crankcase, resulting in a large amount of oil entering the intake tract. Therefore, at this time, cleaning the airway is a symptom rather than a cure, and finding the root cause of the fault can completely solve the problem.
3. Carbon deposition in the intake valve
The intake valve carbon deposit is also deposited by residual fuel vapor and engine oil vapor in the intake pipe. The temperature of this part is relatively high, and the carbon deposit formed is relatively strong and stubborn, and the carbon deposition of some models is serious. For manifold injection engines, due to the cleaning effect of fuel, the intake valve rarely has serious carbon deposition; for the engine of direct injection in the cylinder, there is no fuel cleaning at the intake valve, and most of them will have inlet valve carbon deposition, but the severity is different. So now some models use double injection, using manifold injection at low speed, and direct injection in the cylinder at high speed, which can effectively remove carbon deposits and avoid carbon deposits.
Inlet carbon deposition has a certain impact on engine performance, it will shrink the intake channel, hinder the intake air flow speed, absorb the fuel injected during cold start, resulting in engine cold start difficulties, power drop, idle jitter, etc., tiny carbon particles will also scratch the valve duct, so the carbon deposit in this part needs to be removed in time. The general method of dismantling and removal, commonly known as "coal mining". It can also be washed with walnut sand or dry ice, which can be washed more thoroughly. As for other methods, they are basically ineffective, playing hanging bottles and adding cleaning agents to the fuel tank can only soften part of the carbon deposit, basically can not be removed.
The inlet valve carbon deposits are serious, all of which are direct injection engines in the cylinder, and these carbon deposits are formed by oil vapors. Therefore, the quality of the oil, the gum content, the crankcase ventilation system, etc. will affect the amount of carbon deposit and the formation speed of the intake valve.
4. Carbon deposition in the combustion chamber
I believe that many car owners are frightened by the carbon deposit in the combustion chamber: the repairman removes the spark plug, and then puts the endoscope in, and then lets you look at the screen: Look, this is the black carbon deposit, look at how serious the carbon deposition is, too much, these carbon deposits will hold the piston ring, stuck piston, causing the cylinder, burning oil, carbon deposition is not removed, the engine life is dead!
Many car owners and friends were immediately frightened and trembling, seeing that the car was about to finish playing, and they did not hurry to rescue it? Immediately promised: hurry up, hurry up, wash the carbon deposit for me clean, the cleaner, the more thorough the better, money is not a problem, as long as the engine is good.
Many car owners and friends have paid the IQ tax in this way. In fact, all engines have combustion chamber carbon deposits, and mild combustion chamber carbon deposits have a negligible impact on engine performance. If there is a very serious combustion chamber carbon deposit, it must be a serious oil burning failure of the engine. Here please clarify this logical relationship: it is a serious oil failure that causes serious carbon deposition in the combustion chamber, not the burning oil caused by carbon deposition in the combustion chamber! Many repair shops deliberately reverse this logical relationship to fool the owner!
In other words, mild combustion chamber carbon deposits do not need to be washed at all, and serious combustion chamber carbon deposits are useless when washed, and will be generated quickly. Therefore, no matter which kind of combustion chamber carbon deposit cleaning method, it is useless. Now the most popular dry ice cleaning combustion chamber carbon deposition, it is true that the combustion chamber wall can be cleaned as shiny as new, but it does not make any sense, and dry ice cleaning carbon deposition also has the risk of pulling the cylinder, which is very undesirable. As for other cleaning methods, such as adding carbon remover to the fuel tank, playing hanging bottles, etc., they can only soften the carbon deposit to a certain extent, and basically cannot be removed.
5. Piston and piston ring carbon deposits
In my previous article "Popular Science: How Does Carbon Deposit Trap the Piston Ring and Cause the Engine to Burn Oil?" ", has been the piston, piston ring carbon deposition has been explained in great detail, interested can read it by themselves, here only say the conclusion: the piston head, the top bank, the carbon deposit in the air ring groove, has no impact on the performance of the engine; there can be no carbon deposition on the gas ring; the oil ring is the most likely to be stuck by the carbon deposit, and the oil ring jam will cause the engine to burn the oil seriously.
Carbon deposits on the oil rings are caused by oil coking. This part can only be exposed to the oil, so it is impossible to touch the hanging bottle, add carbon remover to the tank, dry ice, walnut sand and other physical and chemical methods to remove carbon deposits. Therefore, the oil ring carbon deposit can only be removed by dismantling and washing or adding cleaning agent to the oil, and other methods are ineffective.
6. Carbon deposition of spark plugs
The spark plug is the flame center of the engine, the temperature is very high, and there is generally no carbon deposition. If there is a serious carbon deposition on it, one reason is that the mixture is too concentrated, the fuel is not burned clean, and carbon particles are deposited on it; another reason is that the engine burns the oil badly, and the oil adheres to the spark plug electrode to form carbon deposit. The carbon deposition of the spark plug will cause the spark plug to be unable to jump off the fire or occasionally break the fire, which still has a great impact on the performance of the engine.
The carbon deposit on the spark plug can only be removed and washed, and other methods are ineffective.
7. Carbon deposition in the injector
The injector has two types: manifold injection and direct injection in the cylinder. Their heads come into direct contact with fuel and oil, forming carbon deposits on the injector head at high temperatures. However, due to the small aperture and high pressure of the injector, the carbon deposit generally does not block the injector, and can only affect the injection angle of the injector. There is also the gum contained in gasoline, etc., which will adhere to the fuel injection plunger, causing the injector to drip oil. Therefore, the injector accumulates carbon, and adding a decarburant to the tank has a certain effect. Some models also stipulate that fuel additives are added regularly in order to clean the injectors and keep the oil circuit clean.
To summarize the above analysis: the carbon deposits that have an impact on engine performance are throttle carbon deposits, intake valve carbon deposits, piston ring oil ring carbon deposits, spark plug carbon deposits, of which the biggest impact is oil ring carbon deposits, which will cause the engine to seriously burn oil, and serious burning oil will lead to serious carbon deposits in the combustion chamber, forming a vicious circle; the impact is very small or no impact is the intake tract carbon deposition, combustion chamber carbon deposits, injector carbon deposits. The various cleaning methods used in the repair shop are most commonly used to remove the useless combustion chamber carbon deposits, and the oil ring carbon deposits that have the greatest impact on the engine are almost no way. So I said: engine carbon deposits do not take apart cleaning, the place to wash can not be washed, washed off are useless flashy!
In fact, from the above analysis, you can also see that the two materials that cause the engine to carbonize are two kinds: fuel and oil, and inferior fuel and oil will definitely cause serious carbon deposition of the engine. Therefore, we must use qualified fuel and suitable oil for our car. Some people are distressed when they refuel and maintain the car, refueling often go to small gas stations, a liter can be cheaper than one yuan, octagonal, but this fuel quality is not guaranteed, if the gum content is too much, it is easy to lead to engine carbon deposition; for maintenance, many people are keen to find what "99 yuan full synthetic package" and other maintenance packages, in fact, you simply think about it, this is simply impossible, inferior oil will directly damage your engine, resulting in engine carbon deposition, burning oil and other failures. Therefore, we must follow the items specified in the instruction manual, use qualified fuel and oil, and maintain it regularly, instead of doing those meaningless maintenance items.