Madeni Yağlar - Giriş

Kapsam Yağlamanın Prensipleri Motor Teknolojisi Motor Yağlaması Motor Yağı Formülasyonu Madeni Yağ Özellikleri You’ll get multiple choice questions throughout the presentation. The first one that comes up with the right answer will get a nice Valvoline gift!

1. Madeni Yağ Prensipleri

Sürtünme İki yüzeyin, birbirleri ile temas halinde iken hareket etmesi ile ortaya çıkan güce sürtünme denir. Bu iki yüzey her ne kadar çıplak gözle pürüzsüz gibi görünse de, mikroskop altında,asperit adı verilen girintili-çıkıntılı ve pürüzler vardır. Sürtünme hareket eyleminin ‘düşman’ıdır. Hangi yöne doğru bir hareket varsa, sürtünme hareketi aksi yöne çeker. Simply stated, friction is reduced by maintaining a film of lubricant between surfaces that are moving with respect to each other, thereby preventing the surfaces from coming into contact and subsequently causing surface damage. Friction is a common element in daily life. One can walk up a steep ramp without slipping back because of high friction between shoe soles and the ramp surface. One can slide down a ski run because friction between packed snow and skis is low. Both cases illustrate friction between ordinary surfaces. The amount of frictional resistance to motion can be expressed in terms of the coefficient of friction: Friction force opposing motion Friction Coefficient  = ----------------------------------------- Load @ right angles to surfaces

Sürtünmeyi Azaltma Birbirine aksi yönde hareket eden yüzeyler arasında madeni yağ, film tabakası oluşturmak suretiyle iki yüzeyin birbirine temas etmesini engeller.Oluşan film tabakası sürtünmeyi azaltarak yüzeyde meydana gelebilecek zararları ve şekil bozukluklarını engeller.Kolay hareket kabiliyeti sağlar. The coefficient is roughly constant for any pair of surfaces. For non-lubricated metal of ordinary surface finish and cleanliness, exposed to the atmosphere, the value may be about 1. For the same metal contaminated by handling, the value will drop to about 0.3 to 0.1. For well-designed and well-lubricated systems, the coefficient may be as low as 0.005. Under very special conditions, values as low as 0.000005 have been attained. By contrast, the coefficient for clean metal surfaces in a vacuum may be as high as 100 to 200 or more, and cold welding due to adhesion can occur. Lubrication is of two general types based on the operating environment; that is, load and speed of the equipment and viscosity of the lubricant. Smooth surfaces separated by a layer of lubricant do not come into contact and, hence, do not contribute to frictional forces. This condition is called hydrodynamic lubrication. Boundary lubrication, on the other hand, arises when there is intermittent contact between surfaces, resulting in significant frictional forces.

Neden Madeni Yağlara İhtiyaç Duyarız? Sürtünme sonucu oluşan aşırı ısınmayı kontrol ederek hareketli parçaların birbirine kaynamasını engeller Aşınma ve yıpranmayı engeller Dayanıklılık ve mukavemeti arttırır Isı transferi sağlar Yüzeyleri ve yağ kanallarını açık ve temiz tutar Paslanma ve Çürümeye (Korozyona) karşı korur Değişken ve uç sıcaklıklarda çalışma imkanı sağlar Sürtünmeyi azaltır – ısıyı taşır – pislikleri bünyesine alır

Isıyı Taşıma Bir soğutucu gibi hareket edip sürtünme ya da yanma veya yüksek sıcaklığa sahip maddelerle temas sonucu oluşan ısıyı taşımak suretiyle uzaklaştırır. Oluşan yüksek ısıyı kendi bünyesinde absorbe ederek yüzeylerin korunmasını sağlar. Heat Removal Another important function of a lubricant is to act as a coolant, removing heat generated by either friction or other sources such as combustion or contact with high-temperature substances. In performing this function, the lubricant must remain relatively unchanged. Changes in thermal and oxidative stability will materially decrease a lubricant's efficiency in this regard. Additives are generally employed to solve such problems.

Pisliklerin Erimeksizin Yağ İçinde Asılı Kalması Su Yağ karterinde biriken nem Asidik yanma ürünleri Üflenen püskürtülen gazlar Partiküller Aşınmadan dolayı oluşan metal partiküller Suspension of Contaminants The ability of a lubricant to remain effective in the presence of outside contaminants is quite important. Among these contaminants are water, acidic combustion products, and particulate matter. Additives are generally the answer in minimizing the adverse effects of contaminants. Deposit Formation The two main sources of lubricant contamination are blow-by from the combustion chamber, and gases and volatiles from the crankcase that are vented into the intake manifold as an antipollution measure. The various gases interact with one another and the lubricant to form soot, carbon, lacquer, varnish, and sludge. Soot particles are hydrocarbon fragments partially stripped of hydrogen atoms. They also contain an appreciable amount of oxygen and sulfur. Soot particles are strongly attracted to one another and to polar compounds in the oil. Soot tends to form aggregates, which have a soft and flaky texture, and is commonly found in the combustion chamber. Carbon deposits are hard and result from the carbonization of the liquid lubricating oil and fuel on hot surfaces. These deposits have a lower carbon content than soot and usually contain oily material and ash. They are commonly found on the piston top lands and crowns, in piston ring grooves, and on valve stems. Lacquer and varnish form when oxygenated products in the lubricant are exposed to high temperatures. Lacquer is often derived from the lubricant and is generally water soluble. It is commonly found on pistons and cylinder walls and in the combustion chamber. Varnish, on the other hand, is fuel related and is acetone soluble. It is commonly found on valve lifters, piston rings, and positive crankcase ventilation valves. Sludge is caused by lubricant oxidation, oxidation and combustion products in the blow-by gas, and the accumulation of combustion water and dirt. It can vary in consistency from that of mayonnaise to a baked deposit. Low-temperature sludge, most prevalent in gasoline engines, is watery in appearance and forms below 95°C. High-temperature sludge is more common in diesel engines and forms above 120°C.

Madeni Yağ Kullanımı All applications do need different lubricants During the training it will become clear that ‘an oil is not an oil is not an oil’

2. Motor Teknolojisi

Bir motorda neler oluyor?

Buji (kıvılcım) Enjektör Egzost Valfi Emme Sübabı Yanma Odası Piston

İçten Yanmalı Motor Tipleri Rotari Motor 2-Zamanlı Motor 4-Zamanlı Motor

3. Motor Yağlaması

Hangi motor parçaları yağlanıyor? Parçalar / Bölümler Şaft Yatağı Dişliler Silindirler Hareketler Dönme Kayma Yaklaşma ve uzaklaşma Bu hareketlerin kombinasyonu

Yüzeyler Bütünüyle Yağ Filmi ile Ayrılmış Hidrodinamik Yağlama Yüzeyler Bütünüyle Yağ Filmi ile Ayrılmış

Motor Yağlaması (II) Hidrodinamik Yağlama oluşturmak için ihtiyacımız olan şeyler: Yeterli miktarda yağ (pompalama) Yüzeyler arasındaki boşluk toleransı ( 0,01mm / 30mm) Doğru viskozite (iç sürtünme) Yeterli hız (basınç) Yeterli tolerans Doğru yatak boyutu Bunlardan birisinin eksik olması durumunda karşılaşacağımız şey: SINIR YÜZEY YAĞLAMASI

Sınır (Yüzey) Yağlaması Yüzey teması ile yük taşınır – Performans Temel olarak Sınır Film Tabakasına bağlıdır

Motor Yağlamasında Kritik Noktalar Silindirler / pistonlar Sübaplar / Krank Mili Hidrolik Kaldırıcılar Aşınma Önleyici Katık Gerekli Cylinders / Pistons No Constant Speed High Pressure on Cylinder Wall High Temperatures ( 3000 C) Low viscosity Valvetrain / Camshaft Camshaft runs at 50% RPM of the engine RPM Small contact area between cams and lifters High pressure by valve springs High viscosity oil required (impossible) Hydraulic Lifters Need a low viscosity oil for quick functioning after cold start

4. Motor Yağı Formulasyonu

Motor Yağları Performans, aşağıdaki hususları yapabilme yetileri ile değerlendirilir: Sürtünmeyi azaltma, Oksidasyona Mukavemet, Minimize edilmiş kirlilik oluşumu, Aşınma ve Paslanma Önleme. Tipik Motor Yağı Formülasyonu Baz Yağlar %70 - 95 Performans Paketi %5 - 20 Viskozite Düzenleyici %0 - 20 Diğer Muhtelif Katıklar %0 - 2

Baz Yağlar Mineral Baz Yağlar, bir hampetrol fraksiyonudur ve hampetrolün diğer fraksiyonlardan distilasyon (damıtma) ile ayrılır. Petroleum was formed many millions of years ago. It is believed to originate from the remains of tiny aquatic animals and plants that settled with mud and silt to the bottoms of ancient seas. As successive layers built up, the deposits were subjected to high pressures and temperatures and, as a result, underwent chemical transformations, leading to the formation of the hydrocarbons and other constituents of crude oil. In many areas, the crude oil migrated and accumulated in porous rocks overlaid by impervious rock that prevented further movement. Usually, a layer of concentrated salt water underlies the oil pool. Crude oil is recovered by drilling holes as deep as five miles into the earth's crust. The crude oil frequently comes to the surface under great pressure and in combination with large volumes of gas. The gas is separated from the oil and processed to remove liquids of high volatility, which constitute "natural gasoline." The dry gas is sold as fuel or recycled back to the underground formations to maintain pressure in the oil pool and, thus, increase crude oil recovery. Crude oils are found in a variety of types, ranging from light-colored oils (consisting mainly of gasoline) to black, nearly solid asphalts. These crudes are highly complex mixtures containing many hydrocarbons, ranging from methane — the main constituent of natural gas with one carbon atom — to compounds containing fifty or more carbon atoms. Crude oils also contain varying amounts of compounds of sulfur, nitrogen, and oxygen; metals such as vanadium and nickel; water; and salts. All of these materials can cause problems in refining or subsequent product applications. Their reduction or removal increases refining cost appreciably. Petroleum lubricating oils are made from the higher boiling portion of the crude oil that remains after removal of the lighter fractions. They are prepared from crude oils obtained from most parts of the world. These crude oils differ widely in properties. An example of the complexity of the lubricating oil refining problem is the variation that can exist in a single hydrocarbon molecule with a specific number of carbon atoms. A paraffinic molecule with 25 carbon atoms, representing a compound falling well within the normal lubricating oil range, would have 52 hydrogen atoms and could have about 37 million different molecular arrangements.

Baz Yağların Madeni Yağa Etkisi Temel Yağ Filmi Kalınlığını Belirler / viskozite Düşük sıcaklık akışkanlığı ve pompalanabilme Yüksek sıcaklıkta tortu oluşumu ve buharlaşma Sızdırmazlık elemanları ile uyumluluk Mineral Bazyağlar Refining processes Solvent Extraction - separates the naturally occurring saturated and unsaturated hydrocarbons. Hydrofinishing - removes some of the nitrogen and sulphur compounds, improves colour, oxidation and thermal stability of base stock. Hydrotreating - converts some of the unsaturated hydrocarbons to saturated hydrocarbons to help improve yield prior to solvent extraction. This process also helps remove of large portion of sulphur and some nitrogen compounds. Hydrocracking - a sophisticated process in which molecules in the base stock fraction are rearranged into the desirable saturated hydrocarbon molecules. The yield of saturated molecules is much greater than that achieved with hydrotreating and solvent extraction. Hydroisomerization - when used along with hydrocracking, can transform the molecules of the base stock fraction into the most stable form possible. Thick base oil  Thick oil film  High internal resistance  Reduces Fuel Efficiency Thin base oil  easy pumpability @ low temperatures  reaches critical engine parts earlier  less engine wear Low quality base stock  more deposits  oil thickening  Reduces Fuel Efficiency  can lead to engine break down Synthetic Base Oils might result in seal swell in older engines leading to engine break down Sentetik Bazyağlar

Sentetikler ve Mineral Daha iyi ilk soğuk çalışma Yağlama Sistemi son noktalarına daha süratli ulaşma Gelişmiş Oksidasyon İstikrarı Gelişmiş akma özelliği Gelişmiş verimlilik – viskozite Daha soğukta çalışma performansı - viskozite Gelişmiş yakıt tasarrufu (%2-3) What is the difference between synthetic and mineral oil? Synthetic lubricants are made up of molecules that have been modified under complex chemical processes and allow for enhanced performance under extreme conditions of temperature, pressure and forces. Mineral lubricants are composed of molecules present in crude oil that are separated in the distillation process at a refinery. Types of Synthetic Base Oils Esthers - avionics oils (temp. resistant -400C to +500C) - synthetics hydraulic oils Glycols - industrial oils (biodegradable hydraulic oils) - not recommended for the systems which were using mineral oils - destroys paint, paper filters, rises viscosity Alkilbenzens - refrigerant oils Poly Alfa olefins (PAO) - motor and industrial oils Phosphat esters - industrial use (fireproof liquids) Silicone liquids - industrial use (heat transfer oils) -DoT5 Advantages of PAO’s (Poly Alfa Olefins): Low Volatility Excellent Miscibility with Mineral Oil Excellent Miscibility with additives Excellent Tolerance for seals Good Air Release properties Good Water separation properties Better Low temperature characteristics - fluidity Excellent Oxidation Stability Good Viscosity/Temperature behavior

Performans paketi formülasyonu Deterjan (Temizleyici) %15 – 20 Dispersant (Ayırıcı / Dağıtıcı) %40 - 50 Diluent oil (Eritici) %10 - 20 Aşınma Önleyici %8 - 12 Antioxidant %5 - 15 Sürtünme Düzenleyici %1 - 2 What are additives and why are they used? Additives are chemical compounds which, when added to base oils, improve the performance of the lubricants; protecting them from aging and allowing them to respond to all the demands of the modern engine. The blend of various additives is what sets a quality lubricant, such as Valvoline SynPower, apart from the competition. Base oil alone is not enough to properly protect your engine. Motor oil needs to perform a wide variety of functions under a wide range of engine operating conditions. Therefore several additives are incorporated into the formulation: Detergent/dispersant additives - used to maintain engine cleanliness, keeping the various contaminants in a fine suspension and preventing them from settling out on vital engine components Rust and corrosion inhibitors - added to protect the engine from water and acids formed as combustion by-products. Antioxidants - added to inhibit the oxidation process, which can result in oil thickening and sludge formation. Anti-wear additives - form a film on metal surfaces to help prevent metal-to-metal contact. Viscosity modifiers and pour point depressants - help improve the flow characteristics of motor oil.

Deterjan (temizleyici) ve dispersanlar (ayırıcılar) Dispersan & Deterjanlar motor parçalarını temiz tutar. Piston Karter Dispersants & Detergents keep pistons clean Major oil contaminants Unburnt fuel (easily degraded) Partially burned fuel Inorganic acids (H2SO4, HNO3) Polar organic compounds Oil and fuel degradation products Wear debris Contaminants in lubricants lead to: Varnish Carbon deposits Sludge - blockage Oil thickening (viscosity increase) Lacquer Rust Bearing corrosion Primary functions of Dispersants in engine oils Maintain cleanliness by keeping ‘dirt’ precursors in solution Soot modification - minimise viscosity increase due to soot build-up in the engine Dispersants should be thermally stable so as not to contribute to ‘dirt’ formation Kabul Edilemez Uygun Kabul Edilemez Uygun

Performans paketi formülasyonu Deterjan Temizleyiciler Yüksek sıcaklık altında çalışan yağlarda motorda yanma olayı sonucu oluşan çeşitli kirleticilerin yüzeylere tutunmasını önleyen katık çeşididir.  Yüksek Sıcaklıkta Tortu Oluşumu Kontrolü Yoğun maddelerin birbirine bulaşmaması kontrolü Asitlerin Nötralizasyonu Paslanmayı Önleme Özelliği Detergents Materials of this type are generally molecules having a large hydrocarbon "tail" and a polar head group. The tail section, an oleophilic group, serves as a solubilizer in the base fluid, while the polar group is attracted to contaminants in the lubricant. Although these compounds are commonly called detergents, their function appears to be the dispersing of particulate matter rather than cleaning up existing dirt and debris. Therefore, it is more appropriate to categorize them as dispersants. The molecular structure and a brief outline of the preparation methods for some representative types of metallic dispersants are discussed below. Dispersants A major development in the additive field was the discovery and use of ashless dispersants. These materials may be categorized into two broad types: high-molecular weight polymeric dispersants used to formulate multigrade oils and lower molecular weight additives for use where viscosity modification is not necessary. These additives are much more effective than the metallic types in controlling sludge and varnish deposits that result from intermittent and low-temperature gasoline engine operation. Compounds useful for this purpose are again characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain. The polar group generally contains one or more of the elements nitrogen, oxygen and phosphorus. The solubilizing chains are generally higher in molecular weight than those in detergents; however, they may be quite similar in some instances. Yağ ile karışabilme fonksiyonu ‘Çengel’ Tamamen farklı bir oluşum

Dispersan Dağıtıcılar Motor yağlarında kullanılan ve yağdaki yabancı partikülleri süspansiyon halinde tutan katık. Bu katık yardımı ile kirler birikerek yağlama kanallarını tıkaması engellenir. Katığın işlev görmemesi halinde yağlama kanalları tıkanır ve yağın yağlama ve soğutma işlevi azalır, buna bağlı olarak yağda lakımsı çamurumsu atıklar oluşur. Katı partiküllerin biraraya gelmemesini sağlar Yağ kalınlaşmasını engeller Motor birikintilerini ve cilalanmayı kontrol eder Viskozite indeksini yapılandırır

Oksidasyon mukavemeti: Havadaki oksijenin yüksek sıcaklık ve kirlilik gibi bazı olumsuz etkilerin yardımıyla yağın  yapısını bozmasıdır. Yağın viskozitesi artar, rengi koyulaşır, asidik tortular oluşur. Kaliteli baz yağ ve oksidasyon engelleyici katıklarla yağa uzun servis ömrü sağlanır. Antioksidant: Yağın okside olmasını engeller Asid oluşumu Çamur ve cilalanma oluşumu Yağ kalınlaşması Yağ ayrışması ve çürümesi Birikinti oluşumu

Aşınma Önleyici Metal yüzeylerde film tabakası oluşturarak metalin metale temasnı engellemeye yardımcı olur. ZDDP tasarruf sağlar Termal kararlılıkla ilgili dengeleme işlevini yerine getirir Fosfor seviyesi spesifikasyonlarla belirlenir Antiwear Additives Wear is the loss of metal with subsequent change in clearance between surfaces moving relative to each other. If continued, it will result in equipment malfunction. Among the principal factors causing wear are metal-to-metal contact, presence of abrasive particulate matter, and attack of corrosive acids. Metal-to-metal contact can be prevented by adding film-forming compounds that protect the surface either by physical absorption or chemical reaction. The zinc dithiophosphates are widely used for this purpose and are particularly effective in reducing wear in valvetrain mechanisms. These compounds are described under oxidation and bearing corrosion inhibitors. Other effective additives contain phosphorus, sulfur, or combinations of these elements. Abrasive wear can be prevented by effective removal of particulate matter by filtration of both the air entering the engine and the lubricant during engine operation. Corrosive wear is largely the result of acidic blowby products formed during fuel combustion. This type of wear can be controlled by using alkaline additives such as basic phenates and sulfonates. Anti Oxidants The corrosion of bearing metal is generally considered to be due largely to reaction of the acid with the oxides of the bearing metal. In engine operation, these acids either originate from products of incomplete fuel combustion that find their way into the lubricant as blowby gases or are produced from lubricant oxidation. Oxidation inhibitors can significantly reduce this tendency. Detergents can reduce bearing corrosion by neutralizing the corrosive acids. Other inhibitors such as zinc dithiophosphates and phosphosulfurized olefins not only inhibit oxidation but also form a protective film on the bearing surface, making it impervious to acid attack.

TBN değeri (Alkalinite): Motor yağının, çalışma sırasında motorda oluşan asidik maddeleri etkisiz hale getiren bazik özelliğidir. Motor parçalarını aside karşı korumada uygun TBN değeri alkaliniteyi artıran katıklarla sağlanır. Dizel motor yağlarının TBN değeri; motorin kükürt içerdiği için önemlidir

Viskozite Düzenleyiciler Viscosity Modifiers provide: Thickening at high temperatures Minimum thickening at low temperatures This allows the formulation of multigrade oils Adequate viscosity at high temperatures for engine protection Low viscosity for easy cold starts Artan Sıcaklık Viscosity Modifiers Viscosity modifiers, or viscosity index improvers as they were formerly known, comprise a class of materials that improves the viscosity/temperature characteristics of the lubricant. This modification of rheological properties results in increased viscosity at all temperatures. The viscosity increase is more pronounced at high temperatures which significantly improves the viscosity index of the lubricant. This is manifested by a decrease in the slope of the viscosity/temperature line plotted on ASTM log paper. Viscosity modifiers are generally oil-soluble organic polymers with molecular weights ranging from about 10,000 to 1 million. The polymer molecule in solution is swollen by the lubricant, and the volume of the swollen entity determines the degree to which the polymer increases viscosity. The higher the temperature, the larger the volume and the greater the "thickening" effect of the polymer. Hence, the oil tends to "thin" less due to increased temperature. In addition to viscosity improvement, the performance of these polymers also depends on shear stability or resistance to mechanical shear and on their chemical and thermal stability. With a given polymer system, shear stability decreases with an increase in molecular weight. The loss due to shear is reflected in a loss in lubricant viscosity. On the other hand, the "thickening power" of the viscosity modifier increases with an increase in molecular weight for a given polymer type. A performance balance must then be established which takes into consideration shear stability and viscosity needs as well as thermal and oxidative stability in actual engine operation. What is a multigrade oil? Lubricants that are able to maintain their performance in high and low temperatures are called multigrade. They are defined by two numbers. The first (followed by a W) indicates the lubricant’s viscosity under lower temperatures. The second and higher number indicates the lubricant's viscosity under greater temperatures. A multigrade lubricant minimises viscosity differences under temperature variations. Major VM TechnologiesType Application Comments Olefin copolymer (OCP) Engine oils Mainline. Cost effective, High volume Styrene butadiene (SBR) Engine oils High performance, Premium products Styrene isoprene (SIP) Engine oils Good performance, Controlled by SICC Radial Isoprene Engine Oils Mainline. Cost effective. Polyisobutylene (PIB) Gear oils Very shear stable Styrene esters (MSC) Driveline oils/hydraulic oils/PPD Cost effective use in ATF Polymethacrylate (PMA) Driveline oils/hydraulic oils/ Versatile technology engine oils/PPD Good low temperature performance

VİSKOZİTE İNDEKSİ: Yağın sıcaklık değişimlerine karşı viskozitelerini koruyabilme özelliğidir. Yüksek viskozite indeksine sahip motor yağları soğukta ince ve akıcı, sıcakta ise kalındır. İndeks numarası yükseldikçe yağın viskozitesinin sıcaklık değişiminden etkilenmesi azalır. Bu özellik madeni yağlarda katıklarla geliştirilir,  Viskozite seçiminde dikkat edilmesi gereken üç özellik: - Hız - Yük  - Sıcaklık Hızın viskozite seçimine etkisi: Düşük hız-yüksek viskozite Yüksek hız-düşük viskozite Yükün viskozite seçimine etkisi: Düşük yük-düşük viskozite Yüksek yük-yüksek viskozite Sıcaklığın viskozite seçimine etkisi: Yüksek sıcaklık-yüksek viskozite Düşük sıcaklık-düşük viskozite

Diğer Muhtelif Katkılar Akma Noktası Düşürücüler (Pour Point Depressant) Sızdırmazlık Uyumluluğu Köpük Önleyiciler Korozyon (Aşınma ve Paslanma) Önleyiciler Yüksek Basınç Katkıları (EP) Sürtünme Düzenleyiciler Boya, Renklendiriciler Pour Point Depressants: Paraffin Wax crystallize at low temperatures PPD’s prevent the congelation of oil at low temperature Seal Conditioners are e.g. used in MaxLife motor oils to prevent leaks Foam on/in an engine oil results in limited lubrication and engine wear Dye has been introduced in lubricants in the US to determine easily whether the engine or the transmission leaks. Typical colors that are being used are red for ATF’s and blue for 2T oils.

Madeni Yağ İmalatı Katık İmalatçıları component 1 Madeni Yağ İmalatçıları Katık İmalatçıları component 1 component 2 component 3  Performans Paketi component 4 component n Viskozite Düzenleyici Baz Yağı Rafinerileri Baz stok 1 Baz stok 2

5. Madeni Yağ Özellikleri Why should I use Valvoline lubricants? Valvoline lubricants minimise contact between parts-in-motion, protecting them from mechanical wear and so reducing the loss of energy caused by friction. They also prevent the build up of sludge deposits that can interfere with the normal function of mechanical elements. Valvoline Lubricants will also: Protect the engine from internal corrosion Remain viscous under all operating conditions Ease cold starts, avoiding wear and tear Cool all parts-in-motion in the engine Allow for a good seal between piston and cylinder Avoid contamination with combustion gases, especially in modern cars

Viskozite Bir sıvının akmaya karşı mukavemetinin ölçümü, gerekli kopma baskısı oranı olarak tanımlanır. Viskozite, göreceli olarak akışkanın kalınlığının ölçüsüdür. Tek Dereceli (monograde) ve çok dereceli (dört mevsim/multigrade) yağlar Motor Yağları: SAE 10W, SAE 40, SAE 15W-40 Dişli Yağları: SAE 80W, SAE 90, SAE 75W-140 Hidrolik Yağlar: ISO-46, ISO-68 Lubricant Viscosity Viscosity is one of the most important properties of a lubricating oil. It is one factor responsible for the formation of lubricating films under both thick and thin film conditions. Viscosity affects heat generation in bearings, cylinders and gears due to internal fluid friction. It affects the sealing properties of oils and the rate of oil consumption. It determines the ease with which machines can be started at various temperatures, particularly cold temperatures. The satisfactory operation of any given piece of equipment depends on using an oil with the proper viscosity at the expected operating conditions. The viscosity of any fluid changes with temperature, increasing as temperature decreases, and decreasing as temperature rises. Viscosity may also change with a change in shear stress or shear rate. For oils of similar kinematic viscosity, the higher the viscosity index, the smaller the effect of temperature. The benefits of higher VI are: 1. Higher viscosity at high temperature, which results in lower engine oil consumption and less wear. 2. Lower viscosity at low temperature, which for an engine oil may result in better starting capability and lower fuel consumption during warm-up. What is viscosity? A liquid that has a relatively high resistance to flow can be described as viscous. For example, water has a low viscosity compared with honey, so in this case honey has a higher viscosity than water under the same temperature. A good quality lubricant keeps its viscosity steady under different temperature and usage conditions for a longer period of time.

Viskozite İndeksi Deneysel ölçümle, belirli bir sıcaklık değişimiyle beraber, viskozitenin değişim oranının ortaya koyulmasıdır. Yüksek Viskozite İndeksi = Sıcaklık Değişirken Viskozitenin Az Değişimi Düşük Viskozite İndeksi = Sıcaklık Değişirken Viskozitenin Fazla Değişimi

Shear Stability – Kopma Kararlılığı (HT/HS) Viskozitenin belirlenen derecenin sınırları içinde kalması performansını sağlar. Geçici viskozite kayıpları (değişimi) ölçümü içindir Shear Stability depends on the mechanical and chemical stability of the viscosity modifiers: Will the multigrade oil stay a multigrade oil over time? Viscosity modifiers are generally oil-soluble organic polymers with molecular weights ranging from about 10,000 to 1 million. The polymer molecule in solution is swollen by the lubricant, and the volume of the swollen entity determines the degree to which the polymer increases viscosity. The higher the temperature, the larger the volume and the greater the "thickening" effect of the polymer. Hence, the oil tends to "thin" less due to increased temperature. In addition to viscosity improvement, the performance of these polymers also depends on shear stability or resistance to mechanical shear and on their chemical and thermal stability. With a given polymer system, shear stability decreases with an increase in molecular weight. The loss due to shear is reflected in a loss in lubricant viscosity. On the other hand, the "thickening power" of the viscosity modifier increases with an increase in molecular weight for a given polymer type. A performance balance must then be established which takes into consideration shear stability and viscosity needs as well as thermal and oxidative stability in actual engine operation.

TBN (Toplam Baz Numarası) Yağın, asitleri nötralize etme yeteneği ile metal parçaları koruması ölçümüdür. Yağın ömrü ile birlikte azalır ve tükenir. Yüksek TBN, daha fazla asit nötralize etme kapasitesini gösterir. Yağın yüksek TBN’e sahip olması, aracın servis görme periyodunu uzatmak anlamına gelmektedir.

Akma Noktası Ya da pompalanabilme Düşük sıcaklıkta ilk çalışmada yağın, motorun kritik parçalarına ulaşabilme yeteneğinin ölçümüdür. Düşük akma noktası, düşük sıcaklıklarda ilk çalışmanın kolay sağlanması ve marş akabindeki yıpranmanın daha az olacağı anlamına gelmektedir.

Noack Buharlaşması Buharlaşma Yüksek sıcaklıklarda yağ eksilmesinin ölçümüdür. Göreceli olarak, yağ tüketimi göstergesi denebilir. Noack değeri ne kadar düşükse yağ tüketimi (eksilme veya buharlaşması) o kadar azdır.

Sulphated Ash (Sülfatlı Kül) Yağdaki ‘metalik’ katıkların seviyesinin ölçümüdür. Bazı motor tasarımları, yüksek seviyedeki küle karşı hassastır. Bir yağın metal içeriğinin/muhteviyatının ölçümü (genelde çinko - Zn, Kalsiyum - Ca, Magnezyum - Mg) Sulfiric asitin varolduğu ortamda yağın yanmasından arta kalan tortunun ölçümü ile hesaplanır. Farklı metaller, sülfatlı kül içeriğine değişik şekilde katkıda bulunur. Deterjanlar, kül oluşumunu engellemeye en fazla katkıda bulunan katıktır. New Technology EURO-IV lubricants use so-called Low-SAPS additives.

Farklı Uygulamalar için Madeni Yağlar Motor Yağı: İçten Yanmalı Dişli Yağı: Yüksek Basınç Motorsiklet Yağı: Motor + Dişli Yağı Zırai Yağlar: Motor + Dişli + Hidrolik Yağ Dıştan Takmalı : Düşük Sıcaklıklarda Çalışabilme Baz Yağlar Dispersan (Dağıtıcı) & Deterjan (Temizleyiciler) Aşınma Önleyici EP Katıkları (Extreme Pressure) Viskozite Düzenleyiciler

Bir yağ, sadece yağ değildir… Farklı Uygulamalar Uzatılmış Yağ Değiştirme / Yakıt Ekonomisi / Emisyonlar Baz Yağı Çeşitliliği ve İçeriği Yüksek/Düşük Kalite Katık Paketi Katık Paketiyle İşleme ve Birleştirme Oranı Yüksek/Düşük Kalite Viskozite Düzenleyici

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