Smoke temperature of corn oil. Smoke point of oils. What oils to use. How to store oils. What does high oil temperature mean?

The traditional and most common term for the changes in olive oil under the influence of temperature is: oil burning temperature. There are also concepts:

Boiling point of oil
Oil fuming temperature
And additionally the freezing point of the oil

With the boiling point of oil, everything is more or less clear, or rather, relatively unimportant. Now the oil has warmed up, now it has boiled, the process has begun. An important parameter is the one at which, under the influence of temperature, carcinogens began to form. This is where disagreement comes in. Some traditionally call the moment of the onset of the formation of carcinogens the combustion temperature, others insist that this is the smoke point. Although the contradictions here are more far-fetched. What's smoking? Natural olive oil contains small particles of olives. It is they who, when heated, begin to burn, forming smoke. If you continue to heat the oil, then it can not only smoke, but also catch fire. Technically from contact with oxygen in the air.

Opponents of the traditional name tend to define this very moment as the temperature of burning oil. But in domestic conditions, when cooking, it rarely comes to this. Those. of course, you can accidentally splash oil on an open fire, but to bring the temperature of the bottom of the pan to the point where the oil flashes ...

Because of this, speaking about the burning temperature of olive oil (relative to the cooking process and the beginning of the formation of combustion products), you just need to make an allowance for the fact that the very suspension of olive particles starts to burn. Of course, visually it manifests itself as the appearance of smoke and pedants tend to insist on the term "smoke point".

Burning temperature table of various olive oils

You can give the following table, which indicates the combustion (fuming) temperature for different olive oils:

Extra virgin olive oil - 160 С
Extra Virgin olive oil with low acidity - 207 С
Refined Pomace olive oil (pomace) - 238 С

There is still refined Extra Virgin, but in practice this is rare. Painfully valuable and useful product to spoil it with additional cleaning. Just for reference, the combustion temperature of such oil ranges from 200 to 240 C ..

Just for general development. Highest combustion temperature available vegetable oils have an avocado. It is 270 C.

As you can see, you can clearly trace the increase in the burning temperature of olive oil, depending on the depth of processing. The more refined the oil, the higher the combustion temperature.

Additional parameters affecting the combustion temperature

Incidentally, combustion temperature is not the only factor that can describe the effect of high temperatures on oil. Thus, studies have been carried out that have shown that different vegetable oils perceive an increase in temperature differently. So some begin to release carcinogens almost immediately upon reaching the critical (for a particular oil) temperature. With regard to olive oil, it has been observed that it has a certain "margin of safety". Those. when the critical temperature is reached, it seems to resist for some time (from 7 to 10 minutes). It almost does not emit carcinogens and does not smoke.

It is worth paying attention to the acidity. An interesting fact it turned out that the smaller it is, the higher the burning temperature of the oil (with the same presence of cake suspension).

Now a few words about how the heating time affects. The longer the oil is exposed to critical temperatures, the more free fatty acids are formed in it. The more free fatty acids in the oil, the more it smokes. Accordingly, the more carcinogens are released.

It is this fact that lovers will not be superfluous to know to buy fried potatoes or a deep-fried pie wherever in fast food outlets. The benefits of such products are highly questionable, and the water damage is obvious.

Other cooking oils

In domestic conditions, sunflower oil, butter and margarine are most widely used. You can see what the situation is with them. The combustion temperature of these products is as follows:

Refined sunflower oil - 227 С
Butter- 150 C
Margarine - 182 С

Especially for those who like to fry potatoes in lard, we will inform you that the burning temperature of this product is 190 C.

As you can see from the above data, the worst situation is with butter. Its burning temperature is lower than all others. But here's what's interesting. The burning temperature of ghee is already much higher - 252 C.

Since the topic of the fact that many products are prepared with the use of palm oil is being discussed in the press, we will not bypass it either. The parameter of interest to us is - 235 C. In rapeseed - 204 C.

Today we will talk about carcinogens in fried foods.

Carcinogens- chemicals, the impact of which on the human or animal organism increases the likelihood of malignant neoplasms (tumors) or leads to them.

Toxic, carcinogenic and simply harmful substances in oils are formed in two cases:

When heating oils to smoke temperature and higher;
When oils go rancid.

Smoke temperature of vegetable fats and oils

"Smoke temperature"- this is the temperature at which the oil begins to smoke in the pan, from that moment on, reactions are started in it for the formation of toxic and carcinogenic substances. Each type of oil has its own smoke point. In general, all oils are subdivided into oils with high smoke point and with low smoke point.

Oils with a high smoke point are recommended for frying and deep-fat frying. The refining process raises the smoke point. It is strongly not recommended to use oils with a low smoke point for frying. Let me give you the smoking temperatures of some oils.

Oils with a high smoke point:

Peanut - 230 ° C
Grape seed - 216 ° C
Mustard - 254 ° C
Corn refined- 232 ° C
Sesame - 230 ° C
Olive extra virgin-191 ° C
Olive - up to 190 ° C
Palm - 232 ° C
Sunflower refined- 232 ° C
Refined rapeseed - 240 ° C
Rice - 220 ° C
Soybean refined- 232 ° C
Hazelnut oil - 221 ° C

Low smoke point oils and fats:

Walnut oil - 150 ° C
Linseed - 107 ° C
Sunflower unrefined- 107 ° C
Pork fat - 180 ° C
Creamy - 160 ° C

Standard electric stoves usually give a heating temperature of no more than 300 ° C, gas stoves - much higher. There is evidence that a cast iron pan can heat up to 600 ° C on gas stoves! Now it becomes clear why it is so easy to exceed the smoke point of oil.

Toxic substances from heating or rancid oils and how to avoid them

Let's take a closer look at the substances that are formed when oils are very hot or rancid.

Acrolein- acrylic acid aldehyde, which belongs to the group of lacrimal poisonous substances. Due to its high reactivity, acrolein is a toxic compound that is highly irritating to the mucous membranes of the eyes and respiratory tract. Acrolein is one of the products of thermal decomposition of glycerin and fat-glycerides. The process of formation of acrolein begins immediately when the oil reaches its smoking temperature, that is, at the beginning of oil combustion. I think everyone's eyes were pinching when the oil burned, they also say about such cases "there is a scum in the kitchen" - this is acrolein. Therefore, NEVER heat oils to a smoking state!

Acrylamide-acrylic acid amide. Toxic, affects the nervous system, liver and kidneys, irritates mucous membranes. In fried or baked foods and baked goods, acrylamide can form in the reaction between asparagine and sugars (fructose, glucose, etc.) at temperatures above 120 ° C. Simply put, acrylamide is formed in the fried crust of starchy foods, such as potatoes, donuts, pies, that have been fried for a long time or at high temperatures in vegetable oil. Acrylamide is formed especially actively when deep-fried for a long time. Some unscrupulous manufacturers of fried foods, in order to save money, use the same oil several times, continuing to fry more and more portions of products on it. In this case, the poison is formed inevitably. Therefore, I strongly recommend not to fry at high temperatures for a long time and refuse deep-frying.

Free radicals and polymers of fatty acids and heterocyclic amines- are actively formed in fume and combustion products. Amines are highly toxic substances. It is dangerous to both inhale their vapors and contact with the skin.

Polycyclic substances with a high carbon content(coronene, chrysene, benzpyrene, etc.) - are strong chemical carcinogens and are also formed in fumes and combustion products. For example, benzpyrene is a chemical carcinogen of the first hazard class. It is formed when products are burnt: cereals, fats, is found in smoked products, products "with a smoke", is present in smoke, substances obtained by burning tar. The EU Commission Regulation No. 1881/2006 of 19.12.06 determines that vegetable oils and fats must contain less than 2 μg of benzpyrene per 1 kg; in smoked products up to 5 μg / kg; in cereals, including baby food, up to 1 μg / kg. Attention! In some cases, for example, in overcooked barbecued meat, it can contain up to 62.6 μg / kg of benzpyrene !!!

When oils go rancid, predominantly aldehydes, epoxides and ketones are formed.... Interacting with oxygen in the air when exposed to light and heat, the oil changes its taste qualities and odor. For fats in which saturated fatty acids predominate, the formation of ketones is characteristic (ketone rancidity), for fats with a high content of unsaturated acids, aldehyde rancidity is characteristic.

Ketones- toxic. They have an irritating and local effect and penetrate the body through the skin. Certain substances have a carcinogenic and mutagenic effect.

Aldehydes- toxic. They are able to accumulate in the body. In addition to the general toxic, they have an irritating and neurotoxic effect. Some are carcinogenic.

Therefore, friends, if you can't completely eliminate fried food from the diet, please, fry correctly, based on this article and follow the simple tips below:

Do not bring the oil to smoke point;
Avoid prolonged frying in oil such as deep fat. If you do fry, do not use the same serving of oil several times;
Do not overcook food. Remember that burnt food contains toxic substances and carcinogens;
For frying, choose only refined oils and fats with a high smoke point;
Store oils according to the instructions on the label and do not use rancid oils.

Smoke temperature tables for oils and fats

The sign "*" near the temperature marks those oils / fats for which the English-language Wikipedia does not yet know reliable sources. Nevertheless, in principle, you can be guided by these values - I think this information is still more reliable than the one that can be found on the Russian-language Internet.

If you are browsing the site on a smartphone, and the table does not fit on the screen, and even the screen rotation does not help, well, or just if it is more convenient for you, then here is a table in the form of a picture.

Fuming temperature of vegetable oils

Avocado		270 ° C
Peanut	unrefined	160 ° C *
Peanut	refined	232 ° C
Grape seed		216 ° C *
Mustard		254 ° C *
Walnut	unrefined	160 ° C *
Walnut	semi-refined	204 ° C *
Camellias		252 ° C *
Castor	refined	200 ° C
Coconut		177 ° C
Coconut		204 ° C
Hemp		165 ° C *
Corn	unrefined	178 ° C
Corn	refined	232 ° C
Sesame	unrefined	177 ° C
Sesame	semi-refined	232 ° C
Linseed	unrefined	107 ° C
Macadamia		210 ° C *
Margarine		182 ° C *
Almond		216 ° C *
Olive	extra virgin	160 ° C
	extra virgin, low acidity	207 ° C
	virgin	210 ° C
	refined or tasteless	199 ° -243 ° C
	pomace (obtained from pomace)	238 ° C
Palm	diffracted	235 ° C
Sunflower	unrefined	107 ° C *
	semi-refined	232 ° C *
	refined	227 ° C
	high oleic, neraf.	160 ° C *
Rapeseed (canola)	unrefined	107 ° C
	refined	204 ° C
	wrung out on the expeller	190 ° -232 ° C
	high oleic	246 ° C *
Rice		254 ° C *
Safflower	unrefined	107 ° C *
	semi-refined	160 ° C *
	refined	266 ° C
Soybean	unrefined	160 ° C *
	semi-refined	177 ° C *
	refined	238 ° C
Hazelnut		221 ° C *
Cotton		216 ° C

Smoke temperature of animal fats

Most of the types of oils listed above (as well as those not mentioned), often with an organic certificate, you can buy at (with a quick and free delivery to Russia, Kazakhstan, Ukraine and other countries from $ 40). There are also very rare oils such as avocado, macadamia, pistachio and others, as well as real organic ghee from free-grazing cows. And all products are guaranteed quality, no fakes. In general, I recommend - I buy there myself, black cumin, ghee, and more. I take olive, linseed, sesame seeds from us, because there is no worse quality and cheaper. You will find instructions for buying on iHerb.

Of the animal fats, the most easily digestible is the fat of the piglet temp. melting 32 degrees C, horse meat fat 35 degrees C, fat of a young lamb, that is, lamb, temp. melting 38 degrees C, therefore they are the the best choice from animal fats. In turn, beef and lamb fat is the worst choice:

If the pan is not overheated higher 160 deg C , then you can fry in all vegetable oils:
sunflower, corn, soybean, peanut, olive, flaxseed, hemp, cottonseed, except rapeseed and mustard (meaning unrefined oils).
On a palm kernel, palm tree, coconut, despite their high smoking temperature, it is better not to fry, as at a temp. 150-160 degrees C they break down medium-chain triglycerides (MCTs), and the natural structure of these oils is destroyed:

Table 1 (properties of unrefined oils)

In this lower table, we are talking about the preparation of ghee butter (ghee made from butter, by the method of prolonged saponification and subsequent removal of protein and carbohydrate residues:

This lower table shows that at 230 degrees With the use of refined oils of corn, sunflower the crust of bread becomes harmful when baking, and when used olive unrefined - already at 177 degrees C.

This table showswhat to unrefined oilsrapeseed and mustard (according to table No. 1 ) it is worth adding unrefinedlinseed oil and oil walnut not worth frying on ... On all other types of refined and unrefined vegetable oils, you can fry,if you do not overheat the pan higher 160 degrees C:

table 2

(The data of the two tables differ, in particular for linseed oil, so we take a lower value for the smoke point of linseed oil (110 degrees C))

Properties of refined vegetable oils and animal fats:

**************************************

Edible fats

The article outlines the generally accepted view on the use of fats, I highlighted in lilac colorinformation that is related to the harm of fats, but this is not generally accepted ( unhealthy fats- hydrogenated) in all three parts of the post.

Fats are the main source of thermal energy necessary for the vital activity of the human body. Just like proteins and carbohydrates, they are involved in the construction of body tissues and are one of the essential elements his food.

Fats are organic compounds of a complex chemical composition mined from milk or fatty tissue animals (animal fats) or from oil plants (vegetable fats or oils). Everything fats are composed of glycerin and a variety of fatty acids... Depending on the composition and properties of the fatty acids, fats can be solid or liquid at room temperature.

In terms of their caloric content, fats are almost 2.5 times higher than carbohydrates.

Fats should be used in quantities that are most conducive to replenishing energy costs. It has been established that the daily need of an adult healthy person for fat is satisfied by 75-110 grams. It should be noted, however, that the amount of fat in the diet is determined by various circumstances, which include the intensity of labor, climatic characteristics, and the person's age. A person engaged in intensive physical labor needs more high-calorie food, therefore, more fat.... The climatic conditions of the north, requiring a large expenditure of thermal energy, also cause an increase in the need for fats. The more energy is consumed by the body, the more fat is needed to replenish it.

But we must not forget that an excess amount of fat, even in the diet of a healthy person, is harmful. Fats do not dissolve in water or digestive juices. In the body, they are broken down and emulsified with the assistance of bile. Excessive fat does not have time to emulsify, disrupts digestive processes and causes an unpleasant sensation of heartburn. An excess amount of fat in food reduces its digestibility, especially the most important part of food - proteins.

The nutritional value of different fats is not the same and largely depends on the absorption of fat by the body. The digestibility of fat, in turn, depends on its melting point. So, fats with a low melting point, not exceeding 37 °(i.e., the temperature of the human body), have the ability to most fully and quickly emulsify in the body and, therefore, the most fully and easily assimilated.

Low melting fats include butter, lard, goose lard, all types of margarines, as well as liquid fats.

Fats with a high melting point are much less digestible. While butter is absorbed by the body up to 98.5%, mutton fat is absorbed only by 80-90%, beef fat, depending on its melting point, by 80-94%.

The importance of fats in cooking is extremely high. One of the main culinary processes - frying - is usually carried out with the help of fats, since, due to the poor thermal conductivity of the fat, it makes it possible to heat the product to high temperatures without burning or igniting. By forming a thin layer between the bottom of the pan and the food to be fried, the fat helps to heat more evenly. Due to its ability to dissolve some coloring and aromatic substances extracted from vegetables, fat is also used to improve the appearance and smell of food. It is well known to improve the taste and nutritional value of food as a result of the addition of various fats to it.

When choosing fat for cooking a particular dish, the chef must take into account not only its digestibility by the body, which is especially important in the preparation of dietary and baby food, but also how this fat reacts to strong heating. Not all fats can be heated to high temperatures without decomposition, which is detected by the appearance of smoke. The smoke production temperature is different.

Butter, for example, can only be heated up to 208 ° (or even 177?). When the temperature rises, it decomposes and imparts an unpleasant bitterness to the fried product. Pork lard can be heated up to 221 ° without decomposition(or is it 182?), but kitchen margarine - up to 230 °... Kitchen margarines, in addition, contain a small amount of moisture, which makes them very convenient for frying various products ( it does not compensate for their harm).

Ghee also does not withstand high temperatures.... You can use it for frying only when you do not need to heat the product very much and when the frying process is fast.

The choice of fat also depends on how it tastes like the culinary product.

All chefs are well aware that the taste of food is determined not only by the main product, but also by the fat used to prepare it. Fat that does not taste good for a given dish can degrade it. For example, you cannot cook sweet pancakes with jam on beef or lard, and if there were no other fats suitable for these pancakes, then it was impossible to cook and include them in the menu.

The wrong selection of fat for the preparation of this dish is a violation of one of the basic laws of cooking, and only an inexperienced, inept chef uses fats beyond their taste.

The delicate, delicate taste of many dishes corresponds to the pleasant smell and mild taste of butter.

Butter is used mainly for sandwiches, as well as for watering a number ready meals, especially prepared from dietary and gourmet products, as well as for dressing sauces.

You should not use butter for frying, especially since this oil contains up to 16% moisture and therefore splashes heavily. Butter in many cases can be replaced by all types of table margarine ( which will bring additional harm to the body).

Animal fats - beef and lard - are used for hot meat dishes and for frying certain types of flour products.

Lamb fat is successfully used to prepare many dishes of Caucasian and Central Asian cuisine.

Liquid fats - vegetable oils- used in all cases when, according to the recipe, the use of non-solidifying fat is required.

The use of this or that fat for different dishes is often determined by its melting point.

So, in dishes that are served only hot, you can also use refractory fats. For those dishes that are served both hot and cold, refractory fats are not suitable, since they give an unpleasant aftertaste when solidified, as they say, "freeze on the lips." For these dishes, it is advisable to use vegetable and cow oil, margarine, lard. Despite the fact that margarine and lard become dense when they solidify, they quickly melt in the mouth and do not give food a “greasy” taste.

Vegetable fats

Vegetable fats are obtained from oil seeds by pressing or extraction.

The essence of the pressing processes is to squeeze the oil out of the crushed seeds, from which the most of hard shell (peel). Depending on the method of conducting the technological process, cold and hot pressed oil is distinguished. During hot pressing, the crushed seeds are preheated in apparatuses — braziers.

Extraction consists of a number of sequentially carried out operations: cleaning, drying, removing the shell and crushing the seeds, extracting oil from them using special solvents and then removing the solvent from the oil.

Vegetable oil is purified either by filtration or by exposure to alkalis. In the first case, the product is called unrefined, in the second - refined. The oil obtained by extraction is edible only in refined form.

For frying most suitable refined vegetable oil, since the particles of mucous and protein substances remaining in unrefined oil when the fat is heated to a high temperature decompose quickly and can give the fried product a bitter taste and a specific unpleasant ("foul") odor.

Some vegetable oils, in addition to refining with alkali, are subjected to bleaching and deodorization. Deodorization is used to reduce or completely eliminate the specific odor of the oil.

From vegetable oils, the assortment of which is very wide and includes fats differing in their chemical and physical properties, in cooking, sunflower, cottonseed, olive, soybean, peanut oils are most often used, less often linseed, hemp and corn oils are used... In the confectionery industry they use sesame oil, nut oil, and in bakery, mustard oil.

Sunflower oil. Sunflower oil is obtained by pressing or extracting sunflower seeds ().

The oil produced by pressing, especially when hot, has an intense golden yellow color and a pronounced smell of toasted seeds.

Sunflower oil goes on sale refined and unrefined.

Refined and deodorized oil is transparent and almost devoid of specific odor.

According to its commercial qualities unrefined sunflower oil is subdivided into three grades (superior, 1st and 2nd).

Dressings for salads, vinaigrettes, herring are prepared on sunflower oil. It is used in cold snacks, especially in vegetables (squash, eggplant, mushroom caviar, stuffed peppers, tomatoes). The same oil is used for frying fish, vegetables and some dough products.

For salad dressings, as well as for making mayonnaise, refined and deodorized sunflower oil is most suitable.

Olive oil. Olive (Provencal) oil is extracted from the fleshy part of the fruit of the olive tree and from the kernel of its hard bone. The best edible olive oil is cold pressed ().

Olive oil has a delicate, mild taste and pleasant aroma. It is used to prepare dressings, fry some meat, fish and vegetable products.

Cottonseed oil. Cottonseed oil is obtained from the seeds of the cotton plant. For food purposes, this oil must be refined with alkali, since unrefined oil contains a poisonous substance - gossypol(from other inf. sources - it is harmful).

Refined and deodorized cottonseed oil tastes good. The color of this oil is straw yellow.

In cooking, cottonseed oil is used in the same cases and for the same purposes as sunflower oil.

Soybean oil. Soybean seeds contain 20 to 25% oil, which is extracted from them by extraction or pressing. Due to its good taste, this oil is widely used. Therefore, every year more and more areas are sown with soybeans. The main areas of growth of soybeans - Far East, Ukraine, North Caucasus(from other inf. sources - it is harmful).

Soybean oil is used only in refined form and for the same purposes as sunflower or cottonseed oil.

Linseed and hemp oil. After refining, linseed and hemp oil can be used for food purposes, but in cooking these fats are rarely resorted to, since they have very limited storage stability, quickly thicken and are unsuitable for frying, since they give the fried product a specific "olive" aftertaste(from other inf. sources - useful linseed oil, hemp - harmful).

Mustard oil. From seeds of white or gray mustard receive oil, which, after thorough CLEANING, has a pleasant, mild taste. The color of refined mustard oil is intense yellow. The specific smell of this oil, especially well suited to some dough products (mustard bread is prepared in mustard oil), does not make it possible to widely use it for other culinary products(from other inf. sources - it is harmful).

Corn oil. To obtain oil, the corn germ is pressed or extracted. Refined corn oil is golden yellow in color; it is used in the manufacture of confectionery(from other inf. sources - it is harmful).

Peanut butter.Walnut kernel contains up to 58% fat... Cold pressed walnut oil has a light yellow color, pleasant taste and smell; it is used in the confectionery industry. ANDs other inf. sources - walnut oil is harmful in general, but there are other, healthy oils, for example, cashews, almonds, hazelnuts, Brazil nuts, coconut, palm kernel, cocoa butter, pistachio nuts, peach kernel.

Peanut butter. This oil is produced from the kernel of peanuts (peanuts). Cold pressed refined oil has a good taste and pleasant smell. It is used as a salad dressing and for frying. Peanut butter is also used in confectionery production(from other inf. sources - it's really useful). here ; about harmful oils. These four materials in a very non-trivial presentation, still little known, very modern, which we also adhere to (irina_co, kulinarium) .

- Coconut and palm oil are the representatives of medium-chain triglycerides in the world of vegetable oils and fats , on the importance of their use in sports and dietary nutrition.

Inside a running engine, increased loads are created - high temperature and powerful pressure. One of the main requirements for any engine oil is its ability to retain its properties when elevated temperatures... There are two indicators by which the quality of the lubricant is determined:

Flash point and pour point.
Viscosity.

The boiling point of the engine oil must be within the specified range. This is possible only if the lubricant product meets the declared characteristics - the oil must be of high quality. An increase in temperature can lead to damage to the internal combustion engine. Grease boiling occurs with improper maintenance of the power unit and creating a load above the permissible level.

What does high oil temperature mean?

When characterizing a lubricant, two important indicators of high temperature are considered:

permissible;
boiling temperature.

The tolerance factor indicates the optimum oil temperature. There are times when the temperature of the oil in the engine has reached the operating state, and the change in viscosity occurs with some delay.

The shorter this time period, the better the lubricant copes with the main function, which consists in thoroughly lubricating the rubbing surfaces of the working engine parts. When this condition is met, the wear of the motor will not increase even when it is very hot.

Excessive boiling point is dangerous for the engine. Boiling, bubbling and smokiness are unacceptable. The ignition temperature of engine oil is 250 ° C. At the same time, the lubricant is diluted, a low viscosity index indicates poor-quality lubrication and damage to the entire mechanical part of the engine.

It is inadmissible to increase the temperature of the lubricant in a running engine by more than two degrees in one minute.

If the lubricant burns at the same time as the fuel, the concentration of the oil decreases, and the exhaust takes on a characteristic color and odor. Grease consumption increases dramatically. The driver has to constantly fill in new portions.

Neglecting the operating temperature is not recommended, since boiling oil leads to increased wear on the power unit.

Oil burst

Flashing of a lubricant occurs when it is mixed with fuel. This effect occurs when a gas flame approaches it. The grease heats up, high concentration vapors appear, this leads to their ignition. Ignition and flash characterize a parameter such as the volatility of a lubricating fluid. It directly depends on the type of lubricant and the degree of its cleaning.

If the flash point has dropped sharply, it means that there is a serious problem with the engine. These include:

malfunctions in the injection system;
violation of the fuel supply;
failure of the carburetor.

To find out the flash point of a particular lubricant, the working fluid is heated in a special crucible with the lid closed and open. The required indicator is fixed with a lighted wick held over the crucible with hot oil.

When it is heated, the concentration of vapors of the oil product greatly increases. This causes the engine oil to quickly ignite, similar to a fire. Regardless of its type (synthetic or mineral), quality oil not only flashes, it continues to burn.

Pour point of oil

When solidified, the lubricant becomes inactive, its viscosity completely disappears. The lubricant solidifies due to the crystallization of the paraffin. Engine oil changes its properties dramatically at low temperatures. It gains hardness and loses its plasticity.

The lubricant must have optimum temperature indicator, which is in the range between the flash and solidification coefficients.

The values of this parameter with a shift, closer to one or another coefficient, leads to a decrease in lubricating properties and a loss of performance of the internal combustion engine.

Influence of oil viscosity on engine stability

Lubricants are necessary to reduce the frictional forces between the surfaces of working parts and power unit assemblies. When working "on dry" there is a seizure, rapid wear and failure of the entire motor. The main requirements include the following functions:

Elimination of friction between parts.
Free passage of lubricant through all channels of the oil system.

The viscosity index of a lubricant is an important parameter. It is directly related to the temperature of the engine and the environment. The viscosity value may deviate from optimal values due to an increase in temperature inside the motor. To ensure the well-coordinated operation of all systems of the power unit, it is necessary that all work processes take place within the permissible limits.

Determination of viscosity by marking

A branded canister with engine oil of any manufacturer contains detailed information about the viscosity index of the product according to the CAE system. The viscosity designation consists of numerical and alphabetic characters, for example, 5W40.

Here the English letter W speaks about the winter parameter. The numbers to the left and right of it are winter and summer temperature readings, respectively. In this range, stable engine operation is ensured using a specific product.

The influence of low temperatures on the stability of the engine start

Particular attention is paid to the winter indicator. After all, it is at low ambient temperatures that it is difficult to start the engine "cold". The constant number 35 is subtracted from the figure 5. The result obtained (- 30 ° С) is the minimum allowable temperature at which this oil will allow you to quickly start the engine. "35" is a constant for all types of lubricants.

A quick start of a cold internal combustion engine also depends on the following indicators:

engine's type;
technical condition of the engine;
serviceability of the fuel system and battery;
fuel quality.

Why is high temperature in the engine dangerous?

Excessive heating of the engine is much more dangerous than cooling it. The oil boils at 250 - 260 ° C, causing fire, bubbles and smoke. If this situation continues for a long time, the viscosity of the lubricating fluid drops sharply and the parts do not receive high-quality lubrication. In this case, the lubricant product forever loses all its originally useful properties and qualities.

Starting from 125 ° C, the oil evaporates and evaporates with fuel vapors, without getting on the piston rings. The amount of engine oil is sharply reduced, which causes the need for constant topping up.

Causes of excessive heating of engine oil

Aging of the lubricant occurs as a result of oxidative processes occurring in its base. As a result of chemical reactions, negative deposits are released:

Nagar.
Sludge sediments.
Lucky.

These processes are accelerated when exposed to high temperatures.

Carbon deposits are solids that are formed during the oxidation of hydrocarbons. They also include elements of lead, iron and other mechanical particles. Carbon deposits can cause detonation explosions, glow ignition, etc.

Varnishes are oxidized oil films that form a sticky coating on mating surfaces. Under the influence of high degrees, they are baked. They are composed of carbon, hydrogen, ash and oxygen.

Lacquer coating impairs the heat transfer of pistons and cylinders, which can lead to dangerous overheating. Piston grooves and rings, which lie in them due to coking, suffer the most from varnishes. Coking is a harmful mixture of varnish and varnish.

Sludge is a mixture of emulsion contaminants with oxidation products. Their formation is caused by the poor quality of lubricants and a violation of the vehicle's operating mode.

Conclusion

Avoid long journeys at high speed.
Monitor the temperature of the engine oil.
Replace the lubricant at the recommended time.
Use only approved grades of engine oil in strict accordance with the recommendations of the car manufacturer.

The vehicle passport contains detailed information on the brand of engine oil suitable specifically for the specific power unit installed on this machine.