Lubricants are divided into industrial lubricants and automobile lubricants. Among them, vehicle lubricating oil includes engine oil, water tank and cooling system oil, automatic transmission oil, gear oil (for manual transmission), brake and clutch system oil, grease, etc.
Composition of lubricating oil and concepts of synthetic oil and mineral oil.
Lubricating oil consists of base oil and additives. For engine oil, base oil usually accounts for about 90%, and the rest is additives. The quality of base oil is very important to the performance of lubricating oil, which provides the most basic lubrication, cooling, oxidation resistance and corrosion resistance of lubricating oil. However, in order to improve the performance of lubricating oil, lubricating oil also contains additives to improve its comprehensive performance. The additives of engine oil mainly include: anti-oxidation additives, anti-rust additives, anti-corrosion additives, anti-foaming additives, viscosity index improvers, pour point depressants, cleaning additives, dispersants, anti-wear additives and so on. The above additives are not enough, and many properties need to be balanced comprehensively. Therefore, it is necessary to carry out bench test of lubricating oil to determine or evaluate the performance of the formula through its comprehensive performance in the engine.
Because the content accounts for the vast majority, the performance of base oil is very important to the performance of finished lubricating oil. Traditionally, the base oil extracted from petroleum by physical distillation is called mineral oil (some non-deeply hydrogenated base oils are also called mineral oil), and synthetic oil, as its name implies, is the base oil obtained by chemical synthesis (most of its components do not exist directly in petroleum). Synthetic oil and mineral oil have no exact definition, which is commonly known as saying. API (api gravity) classifies base oils into five categories, and the third and fourth types of base oils are usually called synthetic oils.
Common synthetic oils are: PAO, XHVI and esters. In addition, the performance of VHVI base oil is between synthetic oil and mineral oil. Although some people call it synthetic oil, its properties (such as viscosity-temperature characteristics, oxidation resistance, etc.) are far from those of PAO, XHVI and esters. PAO and XHVI are the most widely used engine oil base oils, of which XHVI is a synthetic base oil with patented technology of Shell, synthetic engine oil of Mobil mainly uses PAO as raw material, and the synthetic oil of Castrol mostly uses esters as base oil. The performance of XHVI and PAO is similar, but the antioxidant performance of ester engine lubricating oil is different from the former two.
At present, China's industry keeps up with western new technologies and uses many products from the United States, Japan and Europe. Therefore, the standards of these countries (such as American SAE, Japanese JIS, European CCMC, German DIN, etc. ) has been gradually cited, and the current lubricating oil standards in China (SY, SH, GB) are gradually approaching these standards, especially referring to American SAE standards. Global economic integration is an inevitable trend, and the standards adopted by lubricating oil industries in various countries are gradually consistent or equivalent to each other, and China is no exception. 1. Classification is consistent with ISO (National Organization for Standardization): * * * Thirteen categories. The main categories of internal combustion engine oil, gear oil, hydraulic oil and other oil products are classified according to the latest national standards, and the Chinese standards are synchronized with the national standards.
However, in practical application, there is an obvious gap between China's lubricants and developed countries. For the internal combustion engine oil with the largest consumption, we generally use SD and se grades, while developed countries have used SG and SH grades, with a difference of 2 or 3 grades (in alphabetical order). China can now produce SE, SF and even SH grade internal combustion engine oils, but the key raw materials: composite additives for internal combustion engines still basically rely on imports; This is the actual gap between China and the international advanced level. First of all, help you understand oil drums.
Whether it is Shell Heineken or other brands of engine oil, there are many English and numbers on its oil drums, which are often confused by novices. Although recommended by maintenance workers, the average car owner still doesn't order it. In fact, as long as you understand the simple rules, you can understand the signs on the oil drums and easily choose the right lubricating oil for your car.
SAE is the abbreviation of American Society of Automotive Engineers, and SAE grade represents the viscosity grade of engine oil. SAE30 and SAE40 are single-stage oils, and SAE 10W-30 and SAE 15W-40 are multi-stage oils. Among them, the smaller the number before "w", the lower the low-temperature viscosity, and the better the protection ability of the engine during cold start; The number after "W" is the index of high temperature resistance of oil. Taking Shell Super Heineken Engine Oil as an example, the most typical data is SAE 10W-40.
API engine oil is divided into two categories: "S" series stands for gasoline engine oil; "C" series stands for diesel engine oil; When the letters "S" and "C" exist at the same time, it means that the oil is commonly used in gasoline and diesel. If "S" is in the front, it is mainly used for gasoline engines. On the contrary, it is mainly used in diesel engines.
Second, the engine oil brand recognition
Normally, oil is classified by viscosity and quality. SAE (Society of Automotive Engineers) classification and API (api gravity Gravity) classification, which are widely used in the world, are typical representatives of the two classifications.
According to SAE method, there are 6 kinds of oils used in winter, 4 kinds of oils used in summer and 0/6 kinds of general oils used in winter and summer. The brands of oil used in winter are: 0W, 5W, 10W, 15W, 20W and 25W respectively. The symbol w stands for winter. The smaller the number before W, the smaller the low-temperature viscosity, the better the low-temperature fluidity and the lower the applicable minimum temperature. The brands of oil used in summer are: 20, 30, 40 and 50 respectively. The larger the number, the greater the viscosity and the higher the applicable maximum temperature. The brands of general oil in winter and summer are: 5w/20, 5W/30, 5w/40, 5w/50, 10w/20, 10w/30, 10w/40, 10w/50, and. 20W/30, 20W/40, 20W/50, the smaller the number representing the winter part, the larger the number representing the summer part, the higher the viscosity, and the wider the applicable temperature range.
According to API quality classification, engine oil is divided into gasoline engine oil series (S series) and diesel engine oil system (C series). The series of oil products are arranged in alphabetical order and divided into several grades.
The marks on the oil packages imported from abroad and Hong Kong consist of SAE viscosity classification grade and API quality classification grade. Usually begins with SAE, followed by viscosity code; However, the oil label classified by API quality generally omits API and directly marks the quality grade code. For example, the label is SAEl0WSD, which means winter gasoline engine oil with viscosity classification of SAEl0W and quality star rating of API SD; The label is SAE30SD, indicating that the viscosity is classified as SAE30. Summer gasoline engine oil with quality grade of APISD; The label is SAEl0W-30SD (or SAEl0W/30SD), which indicates that the viscosity classification is general gasoline engine oil that meets both SAEl0W and SAE30 in winter and summer, and the quality grade is API SD.
Before 1980s, there were few specifications and monotonous varieties of engine oil in China. Although there are traditional classification norms, there is no unified national standard. At present, the new national standard classification methods of automobile engine oil formulated in China include GB763 1.3-89-89 domestic internal combustion engine oil quality classification and GAEJ300APR84 oil viscosity classification with the same effect. Gasoline engine oil is divided into five grades: EQB, EQC, EQD, EQE and EQF. The characteristics and applications of these five kinds of gasoline engine oils are as follows:
EQB grade-gasoline engine used for trucks, buses and other vehicles working under mild conditions, with certain detergency, dispersity and corrosion resistance to hydrogenation;
EQC grade-used for gasoline engines such as trucks and buses working under medium working conditions, and can also be used for gasoline engines that require SC grade oil abroad, with good detergency, dispersibility, oxidation resistance, corrosion resistance and permeability resistance;
EQD grade-gasoline engines for trucks or buses and some cars working in harsh conditions, which can meet the requirements of gasoline engines equipped with crankcase forced ventilation devices, as well as gasoline engines that require SD and SC engine oils abroad, and
EQC grade oil has better performance;
EQE gasoline engine is suitable for cars and some trucks working in bad conditions. It can meet the requirements of gasoline engines equipped with tail gas conversion devices, and the performance of similar gasoline engines with SD grade oil abroad is better than EQD.
EQF gasoline engine is used in cars and some trucks working in worse conditions, and can also be used in foreign gasoline engines that need SF, SE, SD and SC oils, and its performance is better than EQE gasoline.
The new domestic oil viscosity classification method is equivalent to adopting the international SAE viscosity classification.
Three, the classification and different characteristics of engine oil
When choosing engine oil, friends often only consider the price and ignore its performance, thinking that the quality of engine oil is similar. The reason for this misunderstanding is that people don't know much about the classification of engine oils and the different characteristics of various types of engine oils.
Characteristics and differences of engine oil
Api gravity (APT) quality classification system is the most widely used engine oil classification system at present. It describes engine oil with simple codes according to its working ability. Where "S" is used for gasoline engines. From "SA" to "SH", with each additional letter, the performance of engine oil will be much better than the previous one, and there will be more additives in engine oil to protect the engine.
Among the characteristics of engine oil, the most important point is its viscosity. For those oils with low viscosity at low temperature and high viscosity at high temperature, which can ensure the normal lubrication of the engine at any temperature, we define them as multi-grade oils. At present, the engine oil on the market is divided into mineral oil and synthetic oil, and the highest grade oil belongs to synthetic oil.
Generally, high-end cars choose synthetic engine oil. The viscosity index of synthetic oil is higher than that of ordinary mineral oil, and the viscosity changes little with temperature, so it can still maintain appropriate viscosity and provide appropriate protection under high temperature and cold conditions. In addition, synthetic oil is not easy to produce acid and sludge due to oxidation, and can provide proper lubrication and effective protection for the engine under various harsh working conditions, so the service life is longer.
The selection and use of engine oil can be based on the following aspects.
Distinguish by quality
Engine oil can be divided into mineral oil and synthetic oil according to different base oils (vegetable oil is not counted because of its scarce output). The biggest difference between them is that synthetic oil has a wider service temperature, longer service life and higher cost; For the same oil film requirement, synthetic oil can be achieved with lower viscosity, while mineral oil needs higher viscosity than synthetic oil to achieve this requirement. In the same working environment, the service life of synthetic oil is much longer than that of mineral oil, so the cost is higher, but compared with the number of oil changes, it is not much higher than that of mineral oil.
(Semi-synthetic engine oil is not involved in this paper) It is distinguished by viscosity.
Viscosity refers to the internal friction when fluids (including gas and liquid) flow, that is, the flow stagnation resistance. Generally, lubricating oil will provide viscosity at 40 degrees Fahrenheit and 100 degrees Fahrenheit, 40 degrees is relative to the condition when the car is cold, and 100 degrees is the condition when the car is driving at high speed or in traffic jam. If the viscosity is too thick, the resistance will increase relatively, so the following unfavorable factors will appear: First, it will affect the start of the engine when the car is cold, which will be more obvious at low temperature. For example, when you go to the snow-capped mountains to enjoy the snow in winter, 20W/50 is not as good as 5W/40. Second, increasing fuel consumption The oil with high viscosity has great resistance, which will cause greater friction resistance when the internal parts of the engine are running, thus increasing fuel consumption; Third, increase the wear and tear when the engine starts. When the engine is not started for a period of time, the oil originally attached to the upper part will flow back to the oil pan, and the upper part lacks enough oil to protect the engine in the starting state. If the viscosity of the oil is thicker, the flow will be slower, so the probability of wear will increase; 4. If the viscosity of the oil is too thick, the internal resistance will be large, and the resistance will be converted into heat energy, which will increase the temperature of the parts during operation.
4. What kind of engine oil is used for EFI vehicles?
Nowadays, the proportion of EFI vehicles is increasing, and many car owners are proud of owning EFI vehicles. Indeed, the EFI vehicle has many advantages, for example, its engine power is higher than that of carburetor engine 15%-20% on average. However, its requirements for engine oil, especially technical indicators such as high oxidation resistance, are becoming more and more demanding.
The EFI engine equipped with three-way catalytic converter device has stricter requirements for engine oil. The installation of three-way catalytic converter must meet two conditions. First, unleaded gasoline must be implemented, because lead in gasoline will poison the catalyst and make it ineffective; two
However, the EFI truck equipped with three-way catalyst must use engine oil with phosphorus content below 0. 12%. If the phosphorus content in engine oil is too high, it will lead to catalyst failure, shorten the life of three-way catalytic converter, and the exhaust gas cannot be minimized. Only when the phosphorus content in engine oil is lower than 0. 12%, the three-way catalytic converter can work normally. The engine oil with phosphorus content below 0. 12% is APISH and above. Therefore, if your car is an EFI vehicle and a three-way catalytic converter is installed, you should use SH or above engine oil when adding engine oil, so as to ensure the smooth and safe driving of your car.
Identification of engine oil quality with intransitive verb
The lubrication system of the engine is very similar to the blood circulation system of the human body. Without healthy blood, the human body can't survive. Once blood loss is excessive or blood quality changes, life will be seriously threatened or even lost. The working quality and service life of an engine largely depend on the quantity and quality of engine oil. A healthy human body has hematopoietic function and can replenish fresh blood in time, but the engine can't do this. In addition, the understanding and attention to the role of engine oil will play a decisive role, and the "life" of the engine is in your hands. For example, the domestic EQ 109 1 truck is not overhauled by 600,000 kilometers, but by tens of thousands of kilometers. The difference is huge. Although there are other factors, lubrication is the main reason. The following focuses on the identification and replacement methods of engine oil quality under simple conditions.
Identification and selection of engine oil quality
(1) Identification and selection of new engine oil quality
At present, the engine oil sold in the market is not so "pure", and the phenomenon of shoddy is widespread. When you need to buy engine oil, if you don't have the ability of quality identification and brand identification, you should ask a specialized technician or an experienced mechanic to help you choose.
1. Observe the color of the oil
Domestic genuine bulk engine oil is mostly light blue with bright luster and uniform flow. Anything with uneven color and different lines when flowing is fake or deteriorated engine oil. If this oil is used, it will seriously damage the engine. The color of imported engine oil is golden yellow with slight blue, crystal clear. Oil drums are exquisitely made, and the edges of patterns and codes are clear and neat, without color leakage or overlap, otherwise they are fakes.
2. Identify the brand of engine oil and test the viscosity.
Domestic barrel oil is divided into gasoline engine oil and diesel engine oil. Gasoline engine oil is divided into four grades according to viscosity: HQ-6, HQ-6D, HQ- 10 and HQ- 15. When the temperature is low, the engine oil with small label or "D" should be selected, and when the temperature is high, the engine oil with large label should be selected. Diesel engine oil is divided into three grades according to viscosity: HC-8, HC- 1 1 and HC- 14, and the selection principle is the same as that of gasoline engines. As China's machinery industry is gradually in line with international standards, the brand of engine oil is also gradually in line with international standards. At present, some domestic engine oils have used imported engine oil standard brands, and the specific selection method is the same.
Take Toyota pure brand engine oil as an example: luxury cars should use 5W-40 all-weather engine oil, which can ensure the lubrication effect of luxury cars, although the price is higher; Supercharged diesel engine should use CD-30 engine oil; General vehicles use SG 10W-30 engine oil in winter and SG-30 engine oil in summer.
Smell
Qualified engine oil should have no special smell, only a little smell. Any engine oil that irritates the sense of smell and smells bad is deteriorated or inferior and must not be used.
(2) Identification of engine oil in use
Identifying the quality of the oil in use is the basis for determining whether it is necessary to change the oil.
1. Distortion identification
Take a little oil out of the oil pan and twist it on your finger. When screwing, if there is a sticky feeling and wire drawing, it means that the oil has not deteriorated and can still be used, otherwise it should be replaced.
2. Identification of dipstick
Pull out the oil gauge and observe whether the scale line is clear in a bright place. If you can't see the scale line through the oil on the oil dipstick, it means that the oil is too dirty and needs to be replaced immediately.
3. Dumping identification
Take a small amount of oil from the oil pan and pour it into the container, then slowly pour it out of the container, and observe the gloss and viscosity of the oil flow. If the oil flow can be kept slender and uniform, it means that there is no colloid and impurities in the oil, which can be used for a period of time, otherwise it will be replaced.
4. Oil drop inspection
Drop a drop of oil on the white paper in the oil pan. If the black spot in the center of the oil drop is large, dark brown or even without particles, and there is little yellow infiltration around it, it means that the oil has deteriorated and should be replaced. If the black spot in the center of the oil drop is small, the color is light, and the yellow penetration marks around it are large, it means that the oil can still be used.
The above inspection should be carried out when the oil has not precipitated after the engine is stopped, otherwise the correct conclusion may not be obtained. Because after the oil is precipitated, it is often good oil floating on it, so only the surface phenomenon is checked, and the deteriorated oil or impurities are left at the bottom of the oil pan, which is easy to cause false detection.
What kind of oil should you use?
According to informal statistics, there are dozens of brands of engine oil in domestic automobile products alone. As long as you go to the automobile department store, all the synthetic and semi-synthetic mineral oils, SG, SH, and real eyes are spent. I really don't know how to provoke it. I really don't know which one to use. Moreover, almost all products recommended by merchants are highly profitable. It's not necessarily really easy to use, but it really applies. We sort out some concepts from the requirements of the car factory, the suggestions of the oil factory and the experience of some internationally renowned teams. I hope you can find the basis for choosing your own oil.
Distinguish by quality
Engine oil can be divided into mineral oil and synthetic oil according to different base oils (vegetable oil is not counted because of its scarce output). The biggest difference between them is that synthetic oil has a wider service temperature, longer service life and higher cost; For the same oil film requirement, synthetic oil can be achieved with lower viscosity, while mineral oil needs higher viscosity than synthetic oil to achieve this requirement. In other words, synthetic oil can protect low viscosity engines under the same working environment. Similarly, in the same working environment, the service life of synthetic oil is much longer than that of mineral oil, so although the cost is higher, it is not much higher than that of mineral oil compared with the number of oil changes. (This article first ignores the so-called semi-synthetic engine oil Confucius saying: I hate purple to seize Zhu)
Distinguish by viscosity
Viscosity refers to the internal friction when fluids (including gas and liquid) flow, that is, the flow stagnation resistance. Generally, lubricating oil will provide viscosity at 40 degrees Fahrenheit and 100 degrees Fahrenheit, 40 degrees is relative to the condition when the car is cold, and 100 degrees is the condition when the car is driving at high speed or in traffic jam. If the viscosity is too thick, the resistance is relatively large, so some situations will occur. Such as: First, when the car is cold, it will affect the engine start. This will be more obvious at low temperatures, such as going to Yushan to enjoy the snow in winter, and 20w/50 will be harder to start than 5W/40. Second, increase fuel consumption. The oil with high viscosity has high resistance, which will lead to greater friction resistance when the internal parts of the engine are running, thus increasing fuel consumption. Third, increase the wear and tear when the engine starts. When the engine is not started for a period of time, the oil originally attached to the upper part will flow back to the oil pan, and the upper part lacks enough oil to keep the engine in the starting state. If the viscosity of oil is thicker, the flow will be slower, so the chance of wear will increase. 4. If the viscosity of the oil is too thick, the internal resistance will be large, and the resistance will be converted into heat, which will increase the temperature of the parts during operation.
Depending on the temperature of the environment.
Almost any automobile factory will suggest the most suitable oil viscosity in the user manual. Porsche is the most critical engine in the world, because it is an air-cooled engine, and everything is cooled only by oil. In its internal technical notice, make a conclusion for each engine submitted for inspection (required by the oil manufacturer). But the most basic thing is that the owner needs to decide what kind of oil to use according to the temperature of the environment. As far as Taiwan Province Province is concerned, the minimum temperature is not lower than 5 degrees Celsius and the maximum temperature is not higher than 40 degrees Celsius. Generally speaking, 10W/40 and 10W/30 are not suitable for this range, but synthetic oil needs at least 5W/40. 5W/30 and 10W/30 are not suitable. The above is the common sense you must know when choosing engine oil, so that the viscosity of engine oil should first be determined according to the temperature of the vehicle environment, and then mineral oil or synthetic oil should be considered in the budget.
What oil is used for pure transportation?
If a car is just a means of transportation and you only need it at work, then car enthusiasts really want to persuade you to sell your car and take a bus instead. Why do you want to add a tail to the queue? 15W/40 Ordinary mineral oil is enough for you. If you want to save the cost of gasoline, the fully synthetic 5W/40 can meet your requirements, because it flows quickly and can reduce the engine wear when you start.
What oil should I use if I like to pull the number of revolutions?
The higher the engine speed, the higher the relative temperature, so you should use oil with higher viscosity. Such as 5W/50, 10W/50 or 15W/50. However, as mentioned earlier, the higher the viscosity, the greater the relative resistance, and the engine performance will be weakened, so synthetic oil can make up for this shortcoming. Because synthetic oil can meet the working conditions that high viscosity must meet with low viscosity compared with mineral oil. However, at this time, you should consider the engine volume output of the vehicle itself. For example, a four-cylinder car under 2000 will reach the red line as soon as it is pulled. Maybe a little thicker engine oil (such as 10W/40 versus 5W/40) will be more suitable. Because the gap between the cylinder and the piston ring is sealed with engine oil, the sealing effect with high viscosity is of course better. For cars with more than 3000 cylinders and more than 6 cylinders, the engine revolutions of such cars are usually unlikely to reach the red line (of course, there are exceptions), so they don't need much attention. Another way to determine viscosity is to pay attention to the engine valve sound after running for a period of time. If the "da da" sound is obvious, the viscosity should be increased.
What oil should be used for high compression ratio engines?
We tell you subjectively that synthetic oil with high viscosity is the only choice. Such as 5W/50, 10W/50 or 15W/50. If you add that you often pull the number of revolutions to the red line, 10W/60 can be considered.
Eight, how much fuel consumption is appropriate?
First of all, we should establish a correct concept of oil consumption (commonly known as "burning" oil). As long as the engine is running, there will be oil consumption Normal oil consumption is necessary to keep the engine running, so it will not harm the engine. It is a very normal phenomenon for an engine to "burn" engine oil as well as "burn" gasoline, except that the amount of engine oil consumed during normal operation is far lower than that of gasoline (international fuel-oil ratio < 65438+).
During the normal operation of the engine, a small amount of engine oil will enter the cylinder through various channels and be discharged into the atmosphere after combustion. There are three main ways for oil to enter the cylinder. One way is to pass through the gap between the valve stem of the intake valve and the exhaust valve and the valve guide, and a small amount of oil must pass through the valve oil seal to prevent the valve from getting stuck in the valve guide. The other way is the gap between the piston and the cylinder wall, and the piston ring brings the residual lubricating oil film on the cylinder wall into the combustion chamber during the upward movement; Another way is that atomized oil particles enter the combustion chamber through the crankcase forced ventilation pipeline. It can be seen that all the consumed engine oil is finally "burned" in the main combustion chamber and discharged into the atmosphere through the exhaust system. Therefore, people usually refer to the engine oil consumption as "burnt out" engine oil. Although the consumption of this kind of engine oil is not large, it can still be noticed that the amount of engine oil is decreasing after a period of use, so it is necessary to check the amount of engine oil regularly and add an appropriate amount of engine oil as needed.
So, how much oil does it normally consume? This is probably the most concerned issue for most drivers' friends. According to China's international GB3743-84, the fuel consumption rate of engine oil is < 1%. According to this calculation, the displacement of the engine is1.6-2.0l, while the fuel consumption of a vehicle with100km (15 urban circulation) is10l, and its fuel consumption should be
Although all the consumed engine oil is discharged into the atmosphere by the exhaust system after burning in the combustion chamber, if the engine oil consumption does not exceed the standard requirements, it will not affect the emission index of the whole vehicle, nor will it lead to the failure or damage of the catalytic reactor, so users need not worry.
Of course, if the fuel consumption is really too high, the reasons may be as follows: 1. Lubricating system leaks oil; 2. The cylinder wall and piston ring are excessively worn or damaged; 3. The valve oil seal is damaged or hardened and aged; 4. too much oil is added, which exceeds the requirements of the oil meter. In case of the above situation, please go to the designated maintenance service station for maintenance. Of course, drivers and friends should pay attention to regularly checking the oil meter during driving, regularly changing the oil and oil filter according to the requirements of the product instruction manual, adding the oil of the designated brand of the main engine factory and replacing the spare parts of the genuine oil filter.
In short, as long as the automobile engine is running, there will be "burning" engine oil. As long as the "burning" engine oil does not exceed the standard requirements and there is no abnormal phenomenon in the engine operation, it will not affect the vehicle emission index, nor will it lead to the failure of the catalytic reactor, nor will it cause damage to the engine. Users don't have to worry, feel free to drive your car.
Nine, the role and purchase of automobile additives
Generally speaking, there are five kinds of lubricating oil additives, namely detergent, dispersant, viscosity index improver, antiwear agent and antioxidant. In order to further improve the performance of lubricating oil, companies constantly introduce new additives such as antirust agent, metal deactivator, defoamer, emulsifier, demulsifier, adhesive, pour point depressant and synthetic sealing expansion agent. Lubricating oil additive is an indispensable part of modern lubricating oil. Although the addition amount is small, it plays a decisive role in improving lubrication performance and meeting the working requirements under various specific conditions. In practical use, people often want to obtain additives with excellent comprehensive performance, which requires adding a variety of additives, that is, adopting formula technology or compound technology. It is not easy to develop a good additive formula by making a variety of additives into composite additives with excellent comprehensive performance and wide applicability through appropriate preparation technology, because the quantitative relationship between additive addition and performance has not yet been established, and the use of additives mainly depends on the experimental results. There is a synergistic effect between additives, which can be positive or negative, so it is an arduous task to study and develop new composite additives.
At present, there are many kinds of additives on the market with different prices, which often make buyers flinch. In fact, buyers can rest assured that they only need to pay attention to the following matters during the purchase process:
1. Manufacturer's trademark and bar code, to see whether there is certification from authoritative departments, such as ISO-9002 and other international quality standards, to identify the brand of additives purchased.
2. Choose products with moderate prices. The price of additives varies greatly. If the prices of similar additives of two different brands are not much different, the technical content in the products is basically the same, and the only difference is the market positioning. If there is a big gap, it often means that there is a big gap in its internal technical level, and buyers can choose according to their needs.
3. experience. In the history of additives, experience is indeed the most important. If buyers have no experience in using additives, they can consult friends or collect more information to learn, because in any case, it is most important to protect their vehicles.
Discussion on oil change cycle
Generally speaking, the oil change cycle of vehicle oil is 5000 kilometers. Many car owners and friends regard this as a fixed understanding. In fact, due to the difference of engine condition, engine oil used and service environment, the reasonable oil change interval of each vehicle should also be different, and it cannot be generalized.
1. Engine condition
The interior of the new car engine should be clean, with less carbon deposits and other impurities, and the oil change cycle can be appropriately extended. However, it should not exceed 7500 kilometers. No matter how good the engine oil is, it will change its chemical properties after driving for a certain mileage, especially the additive components in it will gradually fail, which will not protect the engine. Old engines, especially those lacking maintenance, contain a lot of carbon glue, and new engine oil is easy to be polluted after being added, causing discoloration and qualitative change, so the oil change cycle should be shortened appropriately. Of course, if conditions permit, it is best to thoroughly clean the inside of the engine.
2. Oil used
There are two criteria for identifying engine oil: quality grade (API) and viscosity (SAE). Quality grades generally range from SC, SD to SJ, and the higher the grade, the better the quality. Modern cars, especially cars, are mostly high-speed engines, which require higher oil products. Generally speaking, engine oils above SF grade have good oxidation resistance, wear resistance, clean dispersion and viscosity stability at high temperature and high shear, which can provide reliable protection for engines and the quality stability will remain unchanged for a long time. Under normal circumstances, it can completely meet the oil change interval of 5000 kilometers. Some car owners, mostly taxi owners, use SD or even SC engine oil to save money, which is not suitable for the oil change requirement of 5,000 kilometers. Because low-grade engine oil has poor stability, rapid deterioration and easy carbon deposition under bad working conditions. From the point of view of caring for vehicles, if this oil is used, the oil change interval should be shortened to 3000 kilometers or even shorter. It is best to use the oil recommended in the vehicle manual, otherwise it may not save money because the oil change interval is shortened.
8. Impact of using environment
The environment also has a certain influence on the engine oil. It is easy to accelerate the deterioration of engine oil in high temperature, extremely cold and dusty environment. The owner should not only choose the appropriate grade and viscosity of engine oil according to the environment, but also shorten the oil change cycle appropriately. The specific requirements depend on the situation, and it is generally appropriate to shorten the period of 1/5- 1/3.
Many car owners have a vague understanding of the use of engine oil, thinking that as long as it is engine oil, it is enough to change it once every 5,000 kilometers. As we all know, improper selection of engine oil type and poor grasp of oil change cycle will have a great impact on vehicles after long-term use. Some of the same models have driven 200,000 to 300,000 kilometers, and the car condition is still very good. In addition to driving methods, the rational use of engine oil is also very important. As long as you can pay attention to summing up experience, carefully compare, scientifically choose engine oil and master the oil change cycle, your car will remain young and enduring forever.