Manufacture of oil > Base oils > Aircraft oils > Engine oils
Modern oil (mineral), synthetic and semi-synthetic motor oil is obtained by mixing base oils with additives of various functional purpose.
As the base oil used frequently (mineral) oils of various viscosity distillate, residual oil and the mixture of distillate and residual components. Also used an oil hydrocracking (HC-synthesis) and synthetic basestocks and mixtures of oil components and synthetic (semisynthetic oils).
To obtain a balanced composition of motor oils that meet the complex requirements, base oils are mixed in certain proportions with antioxidant, detergent-dispersant, protivoiznos-but-extreme pressure, anti-corrosion, depressant, viscosity, foaming and others. Additives. Often use multifunctional additives.
In quantitative terms, motor oils are the largest group produced lubricants (about 40%); their value increased due to increased vehicle fleet. By reducing oil consumption and prolong the change of this growth has not led to an increase in consumption of motor oils. Depending on the application in motor oils contain from 5 to 25% of the additives, except for special highly refined mineral oils (today mainly paraffin).
For special purposes, such as extreme thermal influences, mineral base oils may be partially or completely replaced by synthetic (preferably ethers or olefins oligomers). Oils containing only synthetic base, called "fully synthetic". The fractions obtained by hydrocracking or wax isomerization of individual fractions can be regarded as "semi-synthetic" base oils. They have a particularly favorable viscosity characteristics affecting the properties of their launch and fuel economy, as well as a number of advantages with respect to purity valves, seals and swelling Newtonian viscosity.
At high temperatures, engine oils must retain a sufficiently high viscosity to ensure the proper lubrication and create a tight seal between the piston and the cylinder; at low ambient temperatures, they must allow an easy start of the engine.
Due to the high thermal stresses which are exposed in the engine oil (the temperature range in the area of the top piston rings 200-350 ° C and 100-150 0 C in the crankcase, high demands to the oxidative stability of engine oils. In addition, they prevent sludging and sludge formation and provide a low level of wear and tear even when nebla¬gopriyatnyh operating conditions.
The viscosity of the oil is essential for creating hydrodynamic lubrication regime, such as the connecting rod and crankshaft bearing. To be successful in conditions of boundary lubrication (valves, gas distribution mechanism, the piston) in engine oil antiwear agents administered as well as detergents and dispersants to maintain engine cleanliness.
Recent prevent the formation of carbonaceous and lacquer deposits in the piston-cylinder group. The action of detergents and dispersants is also manifested in the retention of soot and other combustion products in suspension and neutralizing oxidation products and aging.
The oil was presented as a requirement - to prevent low-temperature sludge formation, which occurs when operating in the mode of driving with frequent stops, short run and long-term operation of the engine idling at traffic jams.
Oils for passenger cars must meet the requirements of gasoline and diesel engines and Wankel engines. In light of the ongoing worldwide efforts to protect the environment and fuel economy, diesel engines for passenger cars are becoming increasingly important.
The use of low-viscosity oils helps reduce internal friction, reduced energy losses and fuel consumption. However, the viscosity should be maintained at a certain minimum level to ensure a reliable smazy¬vaniya all pairs of engine friction and low-wear operation even in extreme operating conditions. Fuel savings can also be achieved through optimization of the lubrication by means of so-called friction modifiers.
The oxidative stability of engine oils can be provided using a high quality base oils, antioxidant, detergent, dispersant and anti & wear additives. High oxidation stability is needed to prevent the growth of the oil viscosity during its oxidation and the formation of sludge and varnish; final oxidation products formed from the resins and asphaltenes, which can also cause sticking of piston rings.
Laboratory methods for evaluating the oxidation stability of the duration of which is reduced using high temperatures and contact with air or oxygen, does not give na¬dezhnoy correlation with the oxidation of oils real internal combustion engine. Therefore, the tests used to okisle¬nie in the motor, which resulted in estimated notonly increase in the viscosity of oil, but also the rate of formation of soot, lacquer and resin in the piston area.
Modern motor oils for passenger cars were tested at temperatures in the crankcase oil to 150 ° C, the crankshaft bearing at temperatures up to 180 ° C and in the cylinder-group at an even higher oil temperature. Thermal stability, ability to prevent deposits and wear efficiency at high temperatures are essential svoy¬stvami motor oils.
Motor oil should have good dispersing properties. Low temperature sludge formation due to the oxidation of components of heavy fuel oil in contact with the cylinder walls and then fall into the sump. Acids, metals, salts, sulfur and nitrogen oxides, oxygen and water in crankcase oil prisut¬stvuyuschie contribute to conversion of oil soluble to insoluble products by oxidation and polymerization.
A large amount of sludge may block oil lines and oil filters and cause oil starvation, which may cause neposred¬stvennogo contact metal - metal between the rubbing surfaces and, as a consequence, cause extreme contributions. Therefore, the test engine oils should evaluate their ability to disperse sludge.
The most demanding engine system of the automobile from the viewpoint avto¬mobiley wear considered timing mechanism (cam shaft, push rod, pusher, cam) as the wear of these parts gives adjustment valves. Depreciation timing system depends primarily on the design of the engine and a combination of metals. But is greatly influenced by the composition of the oil. To evaluate the properties of engine oils, other than conventional motor bench test methods have been developed test bench with scrolling engine from the electric motor (without working the engine). On the surface of the cam may occur badass. Due to the rotation of the cam ring risks they leave on the surface of the pusher and chamfer. As a result, metal fatigue occurs as pitting which arises in the center of the end surface of the pusher. On the cam shaft occur scuffing and wear surface. Since all these phenomena belong to the regime of mixed friction, significant improvement can be achieved by the use of anti-wear additives; among them particularly effective dnalkilditiofosfat tsnnka. Improvements can also be achieved using a more viscous oil.
Beginning around 1960, the requirements for engine oils tougher. Power engine doubled (from 25 to 50 liters.), The compression ratio increased from 6.5: 1 to 9: 1. Increased significantly as thermal effects, which are subject to engine components, including engine oil; but the volume of oil has remained virtually the same. Consumption of oil in the engine down, so we can not achieve the "refresh" the oil by topping.
The operating conditions for modern cars are increasingly oscillate between high-speed driving (highway) and slow motion in a column and a short distance (urban conditions).
Terms of oil change, which in 1960 amounted to 3,000 kilometers yes, increased to 10 000 km at present. This was possible due to the continuous improvement of the quality of motor oils, especially in respect of the purity of the piston, preventing low temperature sludge formation, improve the thermal stability and antiwear properties.
With the increasing number of diesel cars should take into account the special requirements for these engines with respect to piston cleanliness and anti-wear
Manufacture of oil > Base oils > Aircraft oils > Engine oils