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A lubricant is a substance that helps to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.
The Wankel engine is a type of internal combustion engine using an eccentric rotary design to convert pressure into rotating motion.
A viscometer is an instrument used to measure the viscosity of a fluid. For liquids with viscosities which vary with flow conditions, an instrument called a rheometer is used. Thus, a rheometer can be considered as a special type of viscometer. Viscometers only measure under one flow condition.
Castor oil is a vegetable oil pressed from castor beans. It is a colourless or pale yellow liquid with a distinct taste and odor. Its boiling point is 313 °C (595 °F) and its density is 0.961 g/cm3. It includes a mixture of triglycerides in which about 90% of fatty acids are ricinoleates. Oleic acid and linoleic acid are the other significant components.
Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, detergents, dispersants, and, for multi-grade oils, viscosity index improvers.. The main function of motor oil is to reduce friction and wear on moving parts and to clean the engine from sludge and varnish (detergents). It also neutralizes acids that originate from fuel and from oxidation of the lubricant (detergents), improves sealing of piston rings, and cools the engine by carrying heat away from moving parts.
A hydraulic fluid or hydraulic liquid is the medium by which power is transferred in hydraulic machinery. Common hydraulic fluids are based on mineral oil or water. Examples of equipment that might use hydraulic fluids are excavators and backhoes, hydraulic brakes, power steering systems, automatic transmissions, garbage trucks, aircraft flight control systems, lifts, and industrial machinery.
Fuel oil is a fraction obtained from the distillation of petroleum. It includes distillates and residues.
Synthetic oil is a lubricant consisting of chemical compounds that are artificially made. Synthetic lubricants can be manufactured using chemically modified petroleum components rather than whole crude oil, but can also be synthesized from other raw materials. The base material, however, is still overwhelmingly crude oil that is distilled and then modified physically and chemically. The actual synthesis process and composition of additives is generally a commercial trade secret and will vary among producers.
Internal combustion engine cooling uses either air or liquid to remove the waste heat from an internal combustion engine. For small or special purpose engines, cooling using air from the atmosphere makes for a lightweight and relatively simple system. Watercraft can use water directly from the surrounding environment to cool their engines. For water-cooled engines on aircraft and surface vehicles, waste heat is transferred from a closed loop of water pumped through the engine to the surrounding atmosphere by a radiator.
Gear oil is a lubricant made specifically for transmissions, transfer cases, and differentials in automobiles, trucks, and other machinery. It is of a high viscosity and usually contains organosulfur compounds. Some modern automatic transaxles do not use a heavy oil at all but lubricate with the lower viscosity hydraulic fluid, which is available at pressure within the automatic transmission. Gear oils account for about 20% of the lubricant market.
The viscosity index (VI) is an arbitrary, unit-less measure of a fluid's change in viscosity relative to temperature change. It is mostly used to characterize the viscosity-temperature behavior of lubricating oils. The lower the VI, the more the viscosity is affected by changes in temperature. The higher the VI, the more stable the viscosity remains over temperature fluctuations. The VI was originally measured on a scale from 0 to 100; however, advancements in lubrication science have led to the development of oils with much higher VIs.
Grease is a solid or semisolid lubricant formed as a dispersion of thickening agents in a liquid lubricant. Grease generally consists of a soap emulsified with mineral or vegetable oil.
The cold-cranking simulator (CCS) is a device used to determine the low temperature performance of lubricants, when starting a cold engine. In this condition, the only energy available to turn the engine comes from the starter motor and the battery, and it has been widely assumed that the system acts as a constant power viscometer. The use of this device for this purpose is standardized as ASTM D5293.
Oil additives are chemical compounds that improve the lubricant performance of base oil. The manufacturer of many different oils can utilize the same base stock for each formulation and can choose different additives for each specific application. Additives comprise up to 5% by weight of some oils.
Crude oil is extracted from the bedrock before being processed in several stages, removing natural contaminants and undesirable hydrocarbons. This separation process produces mineral oil, which can in turn be denoted as paraffinic, naphthenic or aromatic. The differences between these different types of oils are not clear-cut, but mainly depend on the predominant hydrocarbon types in the oil. Paraffinic oil, for example, contains primarily higher alkanes, whereas naphthenic oils have a high share of cyclic alkanes in the mixture.
Crankcase dilution is a phenomenon of internal combustion engines in which unburned diesel or gasoline accumulates in the crankcase. Excessively rich fuel mixture or incomplete combustion allows a certain amount of fuel to pass down between the pistons and cylinder walls and dilute the engine oil. It is more common in situations where fuel is injected at a very high pressure, such as in a direct-injected diesel engine.
Emulsified Fuels are emulsions composed of water and a combustible liquid, either oil or a fuel. Emulsions are a particular example of a dispersion comprising a continuous and a dispersed phase. The most commonly used emulsion fuel is water-in-diesel emulsion. In the case of emulsions, both phases are the immiscible liquids, oil and water. Emulsion fuels can be either a microemulsion or an ordinary emulsion. The essential differences between the two are stability and particle size distribution. Microemulsions are isotropic whereas macroemulsions are prone to settling and changes in particle size over time. Both use surfactants and can be either water-in-oil, or oil-in-water or bicontinuous.
Pour point depressants are used to allow the use of petroleum based mineral oils at lower temperatures. The lowest temperature at which a fuel or oil will pour is called a pour point. Wax crystals, which form at lower temperatures, may interfere with lubrication of mechanical equipment. High-quality pour point depressants can lower a pour point of an oil additive by as much as 40°C.
SAE J300 is a standard that defines the viscometric properties of mono- and multigrade engine oils, maintained by SAE International. Key parameters for engine oil viscometrics are the oil's kinematic viscosity, its high temperature-high shear viscosity measured by the tapered bearing simulator, and low temperature properties measured by the cold-cranking simulator and mini-rotary viscometer. This standard is commonly used throughout the world, and standards organizations that do so include API and ILSAC, and ACEA.
HFRR is a measurement for lubrication of Diesel or heating oil and stands for highfrequencyreciprocatingrig. The value is given in μm, lower is better. The measured value is the diameter of the flattening of the ball after the test.
References
- ↑ H. Shaub; M. F. Smith; C. K. Murphy. STP621-S4 Predicting Low Temperature Engine Oil Pumpability with the Mini-Rotary Viscometer. ASTM International. doi:10.1520/STP27339S.
- ↑ admin (2015-08-08). "How to achieve "real-world" fuel economy gains from your viscosity modifier". F&L Asia. Retrieved 2020-12-03.
- ↑ Stambaugh, R. L. (1984). "Low Temperature Pumpability of Engine Oils". SAE Transactions. 93: 94–101. ISSN 0096-736X. JSTOR 44467123.
- 1 2 Selby, Theodore W.; Miiller, Gregory C. (2008-10-06). "Thermal History of the Engine Oil and Its Effects on Low-Temperature Pumpability and Gelation Formation". SAE Technical Paper Series. Vol. 1. Warrendale, PA. doi:10.4271/2008-01-2481.
- ↑ "YIELD STRESS AND APPARENT VISCOSITY OF USED ENGINE OILS AT LOW TEMPERATURE: ASTM - YONGRUN". www.dgaequipment.com. Retrieved 2020-12-03.
- ↑ https://www.tannasking.com/documents/17/MRV_TP-1_Brochure_2019-01-08.pdf [ bare URL PDF ]
- 1 2 member, Michael J. Covitch STLE (2007-04-01). "Lubricant Additive Effects on Engine Oil Pumpability at Low Temperatures—Detergents and High Ethylene Olefin Copolymer Viscosity Modifiers". Tribology Transactions. 50 (1): 68–73. doi:10.1080/10402000601105540. ISSN 1040-2004. S2CID 219624685.