Car engines must withstand high mechanical thermal loads, so high requirements are placed on the quality of the lubricant. Motor oils have characteristics and many indicators.
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Operating temperature range
Viscosity of motor oils
The lubricant is used to prevent dry friction of the internal parts of the engine. The engine fluid must ensure the separation of friction surfaces, effectively pumping through the oil channels. The temperature (hereinafter temp.) of a flash of a motor lubricant is a parameter that characterizes its volatility.
Characteristics of engine oil - viscosity and dependence on temp. over a wide range.
When creating a car engine, manufacturers, first of all, must calculate the viscosity of the motor oil, which can change with temperature.
Pace. flashes are determined by heating the working fluid in an open or closed crucible, a device where it is poured and heated. To fix the pace. the state of the working fluid should be carried out over the crucible with a lit wick.
Working temp. engine oils should not rise by more than 2 degrees within 1 minute. The lubricant should not only flash, but also burn. Low temp. engine oils increases the viscosity of the fluid, and vice versa.
The viscosity of engine oils, which is indicated in the instruction manual, must be optimal.
The flash point of motor oils characterizes the presence of low-boiling fractions in it. It is associated with such an indicator as the volatility of the oil product during operation. Good working substances have a temp. flash rates over 225°C.
Fractions with a low viscosity, which are available only for low-quality oils, burn out and evaporate very quickly. As a result, the lubricant product is also rapidly consumed. In addition, its thermal properties deteriorate.
35°С - 180°С - these are the operating temperature limits for oils. The temperature state of the working fluid depends on the design of the internal combustion engine and the temp. air. In order to obtain good viscosity-temperature characteristics, oil products are thickened with special additives that allow them to "thin" less when high temperatures are reached. and become thicker at low.
Classification
The operating temperature of a conventional water-cooled engine should be between 80°C and 90°C. Based on this, the working temp. the state of the lubricant should be 10°C - 15°C higher than the temperature state of the cooler, but not reach 105°C.
The operating viscosity may drop below 10 mm2/s. As a result, the oil film will be too thin to be a quality lubricant for all parts in the engine.
It is worth knowing the temperature range for the use of some petroleum products.
The name of winter working fluids contains the letter "W": 4OW, 5W, 10W, 15W, 20W, 25W.
Summer ones are indicated by numbers - 20, 30, 40, 50, 60. Viscosity is higher if the number is higher.
All-weather lubricants have a double designation: SAE 15W-40.
There is a table of values \u200b\u200band characteristics of the viscosity of the lubricant product according to SAE:
The lubricant product is gasoline, diesel and universal, as well as all-weather, summer and winter. The characteristics of the lubricant depend on the base substance, which is the basis and by which mineral, semi-synthetic and synthetic lubricant products are distinguished.
If the temperature range that provides the desired viscosity of the liquid is wide, then its index is also higher, which means that such a product can be called high-quality. The working substance can have both low temp. the state that brings it to solidification, and high, that is, the boiling point. About freezing a little later.
Low temperature
Low temperature parameters
It is important to remember not only the temperature outside, but also the working temp. in the engine, as it is affected by vehicle mileage and loads.
In the engine of each car, two modes of lubricant supply are usually applicable:
- boundary, in which lubrication around the pistons is carried out without pressure;
- hydrodynamic, when the crankshaft is lubricated under pressure.
There are low temperature lubrication parameters. These include:
- crankability, indicating the dynamic viscosity of engine oils and the temperature regime that makes the product liquid, such that it is possible to start the engine;
- pumpability - a condition that allows the oil to pump through the lubrication system.
It should be noted that the operating temperature of pumpability is 5 degrees lower than the temperature state of crankability.
There is a table of temperature states of the oil product.
For all-weather and winter motor oils, a low temperature is important. solidification.
When starting a cold engine or while driving with a low temperature indicator, the slurry enters the most remote places.
The pour point, which affects the flow of the working fluid to the rubbing parts, should be lower than the temp. environment. Pace. solidification of the motor oil product should be 5-10°C lower than the engine start temperature.
Heat
Validity range
What can happen if the engine has warmed up to operating temperatures, however, the viscosity of the lubricant has not decreased to the desired level? Nothing bad will happen under load. The temperature indicators of the motor will slightly increase, and the viscosity will decrease to normal.
The operating temperature indicators of the motor will not exceed the norm for this load and will fall within the tolerance range. But the motor can work for a sufficiently long period of time at high thermometer readings, which will not lead to an increase in its motor resource.
Adding new oil to the engine Boiling temperature
Too much heat in the motor is more dangerous than too little. Increasing the temperature condition can bring the grease to a boil. If it is heated to the boiling stage, you can see how it bubbles and smokes. The grease comes to a boil at 250-260 degrees.
With an elevated temperature state, the viscosity of the lubricant decreases, due to which it will not be able to lubricate the parts with high quality. In addition, reducing the gaps can lead to damage to the mechanism. If the temperature of the lubricant has risen to 125 degrees, then it will burn with the fuel after it bypasses the piston rings.
At the same time, the concentration of lubricant in the fuel will be low, so it will not be noticeable during the exhaust. The liquid will be used up quickly. Therefore, frequent filling with a new one will be required. If the unit requires adding lubrication, then pay attention to this.
Why can't a lubricant be brought to a boil?
An unbearable load on the engine and insufficient care for it bring the liquid to a boiling state, in which it loses viscosity and other necessary qualities.
Flashes and solidification of engine oil
Flashes
The state in which a flash appears on the surface of the lubricant, if a gas flame is presented to it, is called the flash point. When the lubricant is heated, oil vapors are concentrated, which contribute to ignition.
There are differences in the temperature states of flash and ignition, which are associated with the method of testing and with the apparatus itself. The temperature state of flash and ignition are indicators of the volatility of the working substance, which determine its type, as well as the degree of its purification.
But the temperature states of ignition and flash cannot characterize the operation of the lubricant in the engine and its quality.
solidification
If the substance ceases to be viscous and mobile, then this is called the pour point. A sharp increase in viscosity and the process of paraffin crystallization is what characterizes solidification. A lubricant product that is under low temperature conditions becomes immobile and viscous. It gets a firmer consistency and plasticity due to the release of hydrocarbon components.
The pour point is equivalent to the limiting minimum temp. fluid circulation and motor lubrication system.
- A lubricant product that has a high high temperature viscosity is used for sports cars.
- But you should not use a product with such an indicator in a regular car. When choosing a lubricant, you need to focus on the operating instructions for the car.
- Do not use a product with a high level of performance that is higher than that specified by the vehicle manufacturer.
- You do not need to pay special attention to the color of the lubricant, as the additives it contains make it dark.
- Change the lubricant within the time frame indicated by the manufacturer of your car.
- If the car often drives off-road, then such conditions require lubrication changes 1.5-2 times more often than it should be in the instructions.
- Oxoli replacement should be done more often if the car has a significant mileage.
- If the color of the oxol has changed, then this does not mean at all that its operational properties have been lost. Grease washes away deposits in the motor.
- It is best not to mix mineral and synthetic petroleum products.
- Top up with the same grade that is already in the engine.
- You can not flush the engine if the fluid was replaced on time.
Flash point video
Watch a video about the effect of temperature on petroleum products.
May 15, 2015There are a number of requirements for lubricants used in a car and for engine oil in particular, which are associated not only with the features of the physico-chemical processes that occur during engine operation, but also with operating conditions.
In order to have an idea of what factors affect ICE lubricants, one should consider the basic concepts that describe temperature-dependent properties:
- Flash point (t°);
- boiling point;
- Operating t°.
Temperature regime
Lubricants are used to prevent dry contact between the moving parts of internal combustion engines. They are designed to create a sliding boundary and separate rubbing parts. The flash point is related to a parameter such as volatility.
Motor grease has a number of characteristics, including viscosity. Viscosity is directly dependent on temperature. The operating temperature range of internal combustion engines forces manufacturers to take into account the change in viscosity from the moment the engine is started until reaching the optimum mode.
Engine lubrication system
Lubrication of the rubbing parts of the internal combustion engine is carried out continuously during its operation. The simplest system consists of an oil pump that circulates, a filter and channels in the head and cylinder block, crankshaft, etc., through which the lubricant is supplied to the points of contact. As a rule, the lubrication system has several sensors that control the most important parameters of the system:
- Level sensor - notifies the driver that the level has decreased and replenishment or replacement is required;
- Temperature sensor - mainly found on sports cars, the engines of which are constantly under enormous stress;
- Pressure sensor - warns of a drop in pressure in the lubrication system. The cause may be a clogged or defective filter or a clogged oil line.
Determination of volatility
To determine the temperature at which the flash of light hydrocarbon vapors contained in engine oil occurs, it is heated in a special crucible until the vapors begin to flash from an open flame. There is no flash in a running motor, but the lubricant can evaporate and so-called waste occurs. This is a slow and imperceptible process, and the oil level sensor in the end only states the fact. The method for determining the flash temperature is regulated by GOST 6356.
A motor lubricant has two interdependent characteristics - this is viscosity and temperature conditions. With increasing t ° viscosity decreases and vice versa, at low temperatures it becomes more viscous. In the description of the lubricant in the performance data, both parameters are always indicated.
Flashes of volatile hydrocarbons occur when a certain temperature mark is reached, beyond which the process of their boiling and evaporation begins. A flash point of 225°C and above is considered a good indicator; for comparison, diesel fuel vapors flare at +55°. Low-quality oil products with low viscosity contain a large percentage of light fractions that burn out and, as a result, the volume of lubricating fluid decreases, as indicated by the sensor.
The flash point is a characteristic that is more of a laboratory and industrial circulation, and which the vast majority of car owners do not pay attention to. Manufacturers also do not focus consumers' attention on the t ° of the flash, without indicating it on the packaging of motor oils.
terms of Use
The operating temperature range of engine oil lies in the range from -40 to +180 degrees. The industry produces motor lubricants with various viscosity-temperature characteristics corresponding to the required parameters, which in turn are dictated by the characteristics of the power plant and climate. So, in a diesel internal combustion engine, there are different conditions, higher temperatures and fuel composition, which require motor oils of a special formulation. The characteristics of a motor lubricator may vary depending on the structure of its base and a set of modifying additive components that do not allow the oil to become more or less viscous under various temperature conditions, while maintaining lubricating properties. Parameters such as crankability and pumpability depend on environmental conditions.
Low temperature oils
The properties of low-temperature motor lubricants allow the vehicle to be operated in cold climatic conditions, while maintaining all the optimal operating parameters - viscosity, fluidity and adhesion to metal surfaces. 
It is known that the engine lubrication system operates in two modes simultaneously, lubricating moving parts under pressure and without pressure. The pressure is provided by a rotary gear or other type pump.
Under pressure, the surfaces of the crankshaft and camshafts and other motor components are usually lubricated, drip lubrication of the pistons occurs due to oil splashing by moving parts. At low temperatures, it becomes thicker and the effort on the starter increases to turn the crankshaft, the engine starts with difficulty and the “oil pressure” sensor lights up. The grease hardens due to the hydrocarbons of paraffinic origin with a high boiling point that it contains, which tend to crystallize at low temperatures. Low-temperature greases contain a small amount of paraffinic hydrocarbons and special additives that do not allow the grease to thicken in the cold. For heating engine oil, some brands of cars have a forced crankcase heating function that facilitates cold starts.
Influence of high temperatures
The transition of a substance from a liquid state to a gaseous state can be expressed by simple evaporation or occur in the liquid boiling phase. The boiling range of most motor lubricants lies outside the normal operating parameters of an internal combustion engine.
High temperatures in the combustion chamber decompose the lubricant particles that have got there into the simplest compounds in the form of soot, some of which is carried out by the exhaust gases, and some settles in the form of soot on the rings and piston. High-temperature oxidation processes of motor oils contribute to the formation of varnish deposits on the internal surfaces of the engine. The lower the quality of the engine oil, the lower its boiling point.
In automotive internal combustion engines, cooling is usually liquid. The temperature sensor on most cars is triggered when a threshold value of 85-90 degrees is reached, including forced cooling of the engine. The engine cooling system is structurally adjacent to the lubrication system, so for the engine oil to boil, it will be necessary to warm up the engine to a temperature at which the coolant begins to evaporate earlier. For reference, the average boiling point of antifreeze based on ethylene glycol is 120-125 Celsius.
Decrease in engine oil temperature
In sports cars with forced gasoline engines, the t ° of engine oil should not go beyond operating temperatures. To avoid overheating of the oil, a cooling system is installed on the power unit, consisting of an oil cooler, pipelines and a special adapter for an oil filter. A temperature sensor is often installed in the same circuit if the machine is not equipped with it from the factory. This additional cooling function contributes to better heat dissipation of the motor operating under heavy load.
Understanding terms such as flash point, viscosity, thermal conditions, and operating temperature range is just the minimum knowledge of motor lubricant that a motorist needs. If we consider each parameter in more depth, we can find out that the flash point of, say, synthetic oils is on average lower than that of natural oils. Behind the physical processes are chemical transformations of complex substances that a temperature sensor or an oil pressure sensor will not tell about - developers spend huge amounts of money on creating new chemical additive compounds that improve the properties of lubricants.
Conclusion
The vehicle owner's manual will usually list the types of fluids used, including engine lubricants. Deviation from the recommended parameters can lead to overheating and premature wear of the mechanisms.
In Maxime there is a product 3-4 euro (the motor is drawn on it) you spray it on the motor for 10 minutes and then wash it off with a trickle of small water (but it’s better to leave it to dry for 6-10 hours ....) So I did and was satisfied !! !
There is a very wide choice and a huge range of prices for Tvayka behind Aldaris.
synthetics
The motivation is simple - engine oil contains a rich package of additives for various purposes, differs from weapons in a higher workmanship
Therefore, my IMHO, it is necessary to stop collective farming and lubricate with what is intended for weapons. In this case, the weapon will serve faithfully.
You can probably clean a lot of things, but lubricating a weapon with automobile oil is not right, to put it mildly. any auto oil is too thick for this and in the cold there can be unpleasant consequences for the USM in particular.
In addition, automotive, it is also engine oil, does NOT imply that there will be earth and sand on the parts, for example, the part in the engine oil perfectly retains both. Weapons is more liquid and sticks to it less and less. In other words, maybe the local gurus think otherwise, but gun oil was invented in such a way as to best meet all the needs of a weapon and not a motor, and motor oil, on the contrary.
I don't know, I saw a boar. which the peasant lubricated, because of the gun lubricated with a motorka, in the cold it is very interesting - it quietly rattled the bolt frame and non-reloading occurred. He swears that he worked normally on the same cartridges before lubrication. The T-10 may have problems pricking the capsule if the preservation grease is not removed from the firing pin channel.
there are different oils. for example, 0W30,5w30,10w30 and their boiling point is different
about 40g=40ml
It would be possible to estimate, but no, pickup from D-pils will be more expensive))
Can. Mineral water with synthetics is undesirable - it will clog the ducts.
Automotive engines must be able to handle high thermal loads in all operating conditions. It is for this reason that high demands are made on the characteristics of engine oil. Lubrication is used to prevent friction between contacting parts of the power unit. Motor oil separates these parts, quickly passes through all oil channels. The flash point is an indicator that indicates the conditions under which the evaporation of the oily liquid begins.
Whether there is a h Dependence of oil viscosity on temperature? Of course. When manufacturing a machine engine, automakers must determine the viscosity of the oil, which can increase / decrease with temperature changes.
The boiling point is determined as follows. Car oil is heated in a special container. Then the temperature begins to gradually increase (by two degrees per minute). The increase continues until the boiling and burning of the lubricant begins.
The auto-ignition temperature indicates the presence of low-boiling elements in the composition of the oily liquid. This parameter is related to the volatility of the product. High-quality petroleum products can tolerate extremely high temperatures (above two hundred and twenty-five degrees Celsius). Low-viscosity motor oils evaporate at high speed. Because of this, they need to be changed frequently.
From -35 to +180 degrees - this is the usual minimum and maximum operating temperature limit for consumables. The temperature of the oil in the engine depends on the design features of the engine, as well as on climatic conditions. To obtain good temperature-viscosity indicators, the lubricant is made thicker with the help of special additives that reduce the degree of change in the parameters of the oil product during temperature changes.
Temperature ranges
In an ordinary water-cooled motor, the temperature should be between eighty and ninety degrees. Viscosity can decrease up to 10 mm 2 /s. As a result, the lubricating film becomes too thin. It is unable to adequately protect all motor parts while driving.
It is necessary to know the temperature ranges in which it is possible to use various motor oils. Lubricants for winter contain one number and the letter "w" in the marking. Oils for summer are marked with one number. All-weather oil products that can be poured into the engine at any time of the year are marked with two numbers and the letter "w". A special table has been developed in which there is information about all ranges.
Oils are intended for internal combustion engines on gasoline / diesel. There are also universal motor oils. Oil performance depends on the base fluid and additives. Oils are divided into semi-synthetics, synthetic and mineral products.
The expansion of the temperature range leads to an increase in the quality of the lubricating fluid. There is a direct dependence of the viscosity of motor oils on temperature. The higher the temperature at which the engine operates, the thinner the oil.
Low temperature conditions
Not only the street temperature is important, but also the operating temperature, which depends on the mileage of the car, the load. In an internal combustion engine of any car, there are usually 2 modes of lubrication pumping:
- boundary (piston system is lubricated without compression);
- hydrodynamic (crankshaft lubrication takes place with compression).
The low-temperature indicators of the oil include the following characteristics:
- crankability. Indicates dynamic viscosity, the temperature range in which it is possible to start the power unit;
- pumpability. Shows the speed at which the car oil passes through the lubrication complex.
Change in viscosity with temperature It must be said that the temperature range of crankability is five degrees different from the range of pumpability (upwards).
High temperature conditions
What happens if the running engine has warmed up to the optimum temperature, but the viscosity of the oil has not decreased to the required value? It's OK. You just need to wait until the grease takes on the right consistency.
Too much engine temperature is more dangerous than too little. High temperature conditions can lead to combustion of the oil product. When oil boils, it bubbles and smokes. This occurs at a temperature of two hundred and fifty to two hundred and sixty degrees (the range may expand slightly).
At high temperatures, the density of the oil decreases. Therefore, it protects spare parts worse. Reducing the gaps between different parts leads to the fact that the power unit does not operate at full capacity. If the temperature of the oil has increased to one hundred and twenty-five, it will burn out along with the fuel when it passes through all the pistons. The lubricant content in the fuel will be small, its consumption will increase, you will need to constantly pour a new one.
Flashes and freezing of car oil
Flashes
The state in which oil flares up when a gas flame is brought near it is called the flash point. When the lubricant is heated, special vapors (from evaporated oil) accumulate, which contribute to ignition.
This indicator indicates how volatile the oil is, the level of its purification.
Freezing
The state in which the oil loses its viscosity and mobility is called the freezing point. During hardening, the viscosity increases sharply, the paraffin crystallizes. The lubricant becomes harder, more plastic.
Tips for selecting and replacing lubricant:
- Grease, which has a high viscosity at high temperatures, is used in sports cars.
- It is undesirable to pour it into an ordinary car. When choosing a car oil, it is better to rely on what is written in the operating manual.
- It is better not to fill the engine with oil whose characteristics exceed those recommended by the automaker.
- The shade of the oil product does not matter much. The additives contained in the oil give it a black color.
- It is better to change the car oil at intervals determined by the car manufacturer.
- If the car often drives on off-road terrain, it is necessary to change the oil product a couple of times more often than prescribed in the manual.
- If the shade of the consumable has changed, this does not mean that it has lost its own characteristics. The oil washes away deposits from the internal combustion engine that remain in it.
- It is better not to mix mineral water with synthetics.
- When topping up the motor, use the same lubricant that is already filled.
- Flushing is not necessary if the replacement intervals have been observed.
What kind of oil to buy to ensure reliable protection of the parts of your own car? Your best bet, of course, is to choose a product that your automaker recommends. Determining the optimal characteristics of an oil product for an engine is a complex process. The manufacturer conducts many different tests to determine which car oil will be the most suitable for which engine.
In real conditions, the range of permissible temperature conditions may expand. This is due to the climate, which is quite harsh in the Russian Federation (especially in winter). Each motorist should be able to select the optimal lubricant based on the recommendations of the manufacturer of his car, as well as on real road conditions. This provides an opportunity to maximize the operational period of any vehicle, whether it is a passenger car, minibus or truck.
All motor oils have difficult performance characteristics, as they are subject to increased requirements, not only for lubrication and engine protection, but also a modern addition, as coolants.
Accordingly, the complex world of motor oils must withstand high temperatures and perform well in the low temperature range.
As the main characteristics for engine oil, one can cite indicators of its pumping, boiling and burning temperatures.
Oil pumping temperature
The oil pumpability temperature is a parameter that is responsible for the access of the lubricant without obstacles in order to prevent the parts of the power unit from rubbing against each other.
Pumpability and crankability are characteristics that relate to low-temperature conditions.
Ideally, for high-quality motor oils, the formula works that the pumping temperature should be 5 degrees below the cranking temperature.
Everything is logical, otherwise the motor will have a dry cold start. Although modern oils have long been able to provide permanent protection to all parts at the first start after replacement, through the formation of a thin but dense protective film. The features of this characteristic also lie in its two parameters, lubrication under pressure of the piston system and without pressure. The threshold of the lower pour point is indicated individually for each product separately. Based on the temperature parameters, all-weather, summer and winter oils are selected.
Boiling temperature
The boiling point of engine oil is an important parameter that is responsible for the amount of heat in the engine. A constant high level of heat is much more dangerous, as it can cause engine lubricant to boil.
In most cases, motor oils begin to boil at around 250 to 260 degrees Celsius, while the liquid begins to bubble, smoke and form a thick layer of soot.
Boiling is already characterized by a temperature of 125 degrees, which also leads to negative consequences and disrupts the structure of the base of the lubricant product, which at the same time loses its protective properties.
combustion temperature
The combustion temperature of engine oil or flash point - is responsible for the volatility of the oily substance. The lower the volatility, the higher the viscosity of the oil. The same parameter is responsible for the number of top-ups that are not required with a low volatility of the product. In addition, the flash point of the oil indicates the degree of its purification, respectively, the higher this threshold, the better the oil lubricating product is purified.
Working temperature
The operating temperature of the oil in an internal combustion engine has its own standards: it should not increase by more than 2 degrees in one minute. In fact, long-term operating high temperatures are quite acceptable and oil manufacturers often use this. Nothing terrible will happen, but the engine life of the power unit will decrease significantly, instead of the promised long work and clean components.
Important features about temperatures
Having considered the main temperature characteristics of most motor oils, we can conclude that temperature plays an important role in the viscosity of the lubricant product.
Low-quality oils, which have a low boiling and solidification threshold, automatically reduce their own viscosity under operating conditions already in the first 3-5 thousand kilometers. Of course, you should not choose such an oil, as it is guaranteed to lead to breakdowns in the car. The state of aggregation of low-quality oils will also change with temperature changes.
For example, already at minus fifteen, the lubricant will begin to thicken and will resemble paraffin. Accordingly, such oil simply cannot be pumped, but this is not bad. The main thing is that already at minus 10, low-quality oils clog thin engine parts, and only special long-acting products can wash them out of there.
Almost the same picture is drawn at high temperatures. Only low-quality oils in this case do not freeze, but begin to burn and boil like water, since their viscous structure is completely broken.
What is the result?
Repair, at best, of important engine components, and at worst, the car is sent for overhaul with the replacement of the engine and related systems. That's why it's important to understand exactly what each engine oil temperature is responsible for, and how to properly use the data on the packaging, choosing only high-quality proven products.
