Engine carbon deposition is serious, and these driving habits are the main culprit.

Engine carbon deposition is serious, and these driving habits are the main culprit.

First of all, carbon deposition is mainly caused by insufficient internal combustion of the engine.

Yang Qi of Jilin University has a master's thesis, which I want to share with you, "Research on the Control and Evaluation Method of Engine Carbon Deposition", which says so.

The formation of engine carbon deposit is generally due to the insufficient combustion of combustible mixture in the combustion process, so some colloid and residue are formed.

When driving, these behaviors that may lead to insufficient combustion inside the engine are mainly these, and we will talk about them one by one.

I like to warm up my car for a long time.

1, the hot car takes a long time to arrive.

In-situ hot car, the car is idling, the engine intake is quite small, and the combustion conditions are quite poor.

Yao published a paper "Study on Idle Oxygen-enriched Combustion of Gasoline Engine" in Journal of Chongqing Jiaotong University (Natural Science Edition).

This makes sense: the idle speed of gasoline engine is characterized by low speed, fully closed throttle and low fuel supply, but the mixture concentration is high and the atomization is poor.

At this time, it is easy to burn slowly and incompletely, and it is easier to deposit carbon than normal driving at a constant speed.

Is to light the earthen stove, put a lot of firewood in it, and then plug the hole in the stove. It burns very slowly at this time. Maybe some of them are left there in the afternoon and can be used for dinner at night.

In fact, many car owners' manuals also clearly state that there is no need to warm the car in the original place.

For example, the BMW X3 (picture | configuration | inquiry) manual says: Don't warm up when the vehicle is stationary, it's best to start it immediately, and drive at an appropriate speed so that the cooler can reach the working temperature as soon as possible. In other words: heating while walking is actually better than heating the car in situ.

Often drive short distances?

The second type is: often driving for a short time and a short distance.

In this case, it will also lead to insufficient combustion of the engine. Because of this, the fuel injection will be more concentrated during cold start.

Liu Zhiyuan of Northeastern University has a master's thesis to share with you, "Study on Emission and Control Technology of Gasoline Engine in Cold Start", which was mentioned above.

When the room temperature is in the range of-12℃ to 22℃, in order to ensure the normal operation of the engine, it is necessary to enrich the fuel in the combustion chamber during cold start. At this time, the combustion in the engine is not very good. In fact, there is no way for combustible mixtures to burn completely. If the combustion is not clean, carbon deposit will be formed.

Was there a lot of smoke when the earthen stove was first lit? If this kind of cigarette is left there all the time, it will also become carbon and accumulate carbon. On the other hand, when the car is turned off, the fuel injection will not stop immediately, but will be delayed for a few seconds.

Or the previous paper, "Research on Control and Evaluation Method of Engine Carbon Deposition", said so. When the engine is turned off, in order to ensure the necessary fuel pressure of the fuel system, the on-board computer will control the electric fuel pump to work for 2 to 3 seconds to supply fuel. At this time, the engine did not work. In fact, part of the fuel entered the combustion chamber.

That is, the mixture was sprayed in, but it has stopped burning. At this time, it will volatilize, and these waxes and gums will precipitate to form carbon deposits.

Often drive in traffic jams.

The third is: I often drive in traffic jams.

Many car owners and friends usually drive to and from work in the city, right? Is it often a "stop-and-go" working state?

At this time, the engine is in a low load state, which is easy to produce carbon deposition.

Ma Kangkang of Yanshan University has a master's thesis to share with you, "Research on Variable Displacement Control Strategy of Engine Cycle".

As mentioned above, the loading rate of cars that often drive in urban areas is usually only 20% to 50%; When driving at high speed, the load rate of the engine is generally 50% to 90%.

Generally speaking, the lower the engine load rate, the worse the combustion situation.

Wang Zhixin also has a paper in Gansu Science and Technology Vision magazine, in which the harm and prevention of carbon deposition in automobile engines are also mentioned.

When the engine is running at low load, the combustible mixture in the cylinder cannot be completely burned.

The mixture with insufficient combustion and a small amount of engine oil are mixed in the combustion chamber, which is more likely to form carbon deposits in the parts with relatively low engine temperature.

Frequent addition of inferior oil will also lead to more serious carbon deposition.

In addition to those habits when driving, if you are greedy and cheap when refueling, you will really add this 50% discount gasoline, the inferior gasoline of a small workshop ... you don't know, but the price is a little bit, which may really make the carbon deposition more serious.

At present, the quality of domestic gasoline is relatively high, which has caught up with the EU standards, but there is still a gap compared with the United States. At present, taking olefins as an example, the national standard GB 17930-20 16 "Motor Gasoline" stipulates that the olefin content of China 6A gasoline shall not exceed 18%.

The federal standard in the United States is that the olefin content does not exceed 10%. Olefin in gasoline is one of the main reasons for carbon deposition. Zhang Hongzhou and others published a paper "Formation Mechanism and Countermeasures of Carbon Deposition in Turbocharged Direct Injection Engine" in Automotive Technology magazine, which was mentioned above.

Olefins are easily oxidized into colloids at room temperature and in liquid phase. When the temperature exceeds 70℃, the colloid will form a polymer and become a deposit on the metal surface, that is, carbon deposition.

The olefin content of gasoline that meets the domestic standards is already a little high, 18%.

If you go to some unreliable or even black-hearted gas stations and get some unknown or even inferior gasoline, it is not in line with the national standard.

If it is added for a long time, the carbon deposit will become more and more severe, and the money for removing carbon deposit may be more expensive than the oil money saved.

Bad driving habits will make the engine accumulate more carbon?

Generally speaking, some bad habits when driving will really make the engine accumulate more carbon, so driving at ordinary times can be avoided as much as possible.

Aiming at the problem of oil products, it is not completely helpless.

Just add some additives to gasoline that can inhibit the formation of carbon deposits and remove them. This thing is called "fuel treasure" in the local dialect, which is not rigorous, but should be called "Clean fuel treasure".

Because there is fuel treasure with octane number adjustment, I am a 95 car and I can't get it. I can only add 92 and one bottle. It's not clean, but a clean fuel treasure can do it. '