Oil additives are chemicals added to lubricants to enhance their performance, protect machinery, and prolong the life of the oil itself. These additives provide various benefits, such as improving lubrication, reducing wear and tear, preventing oxidation, and maintaining cleanliness within engines and other mechanical systems. Here are some common types of oil additives and their
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When oil is squeezed between surfaces, like a bearing and a journal, VII polymers can align and stretch, causing a temporary drop in viscosity. Once past the bearing, the polymers return to their original shape, restoring viscosity. This temporary shear-thinning happens as the oil film thickness reduces temporarily under pressure but recovers once the stress
High stresses in engine areas such as the oil pump, camshaft, and piston rings can severely affect an oil’s viscosity, causing it to thin out and lose its load-carrying ability under high temperatures and shear forces, leading to engine wear. As shear rate increases, oil viscosity decreases. Multi-grade oils contain VII, which are large, flexible
VII come in various shapes, sizes, and quality levels, with larger molecules generally being better thickeners but more prone to breaking, affecting shear stability. Thickening Efficiency (TE) measures the increase in kinematic viscosity at 100°C after adding a specific amount of polymer. Higher TE indicates more effective thickening, influenced by polymer chemistry and molecular weight.
Oil companies developed multi-grade oils in the 1940s. These oils, like SAE 10W-30, meet both low- and high-temperature grade specifications. By adding Viscosity Index Improvers (VII), which are large oil-soluble polymers, the oils resist thinning as they heat up. For instance, a 10W oil thins to about 5 cSt at operating temperature, but with VII,
Oil Viscosity Grade Numbers (e.g., the 10W and 30 in 10W-30 oil) represent the oil’s viscosity range and limits, not its actual viscosity. Since viscosity varies with temperature, the temperature must be specified for accurate readings. For example, a 30 grade oil has a kinematic viscosity of about 10 cSt at 100°C, ideal for most
The SAE J300 Engine Oil Viscosity Classification provides a standardized way to categorize oils based on their viscosity at different temperatures, helping consumers and manufacturers choose the right oil for specific applications and climates. In 1911, the Society of Automotive Engineers (SAE) introduced the SAE J300 Engine Oil Viscosity Classification, a numerical code system designed
American engineers noticed that oil from Texas Gulf crude was much thicker at sub-zero temperatures compared to oil from Pennsylvania crude during World War II. This observation came to light when the U.S. military required large quantities of oil for use in various theaters of the war, including cold environments. Engineers and researchers discovered that
Dynamic viscosity measures a fluid’s resistance to deformation by shear or tensile stress, usually in centipoise (cP) or millipascal-second (mPa·s). It describes the internal friction in a fluid layer between moving plates, where higher friction requires more force to maintain movement. Dynamic viscosity varies with temperature, so measurements must include the temperature. Tools like the
Viscosity measures a fluid’s resistance to flow, reflecting its internal friction. High viscosity means the oil is “thicker” or “heavier,” while low viscosity means it’s “thinner” or “lighter.” For example, honey is thicker (higher viscosity) than water. Viscosity inversely relates to fluidity and changes with temperature. Hotter oil becomes thinner, reducing engine protection, while colder