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Vapor Lock Properties

Condition wherein the fuel boils in the fuel system forming bubbles that retard or stop the flow of fuel to the engine.

Vapor Pressure Parameters

The measure of a liquids volatility. The higher the pressure at a standard test temperature, the more volatile the sample, and the more readily it will evaporate.

Varnish Chemicals

A deposit resulting from oxidation and polymerization of fuels and lubricants. Similar to but softer than lacquer.

VI Parameters

Viscosity Index

VII Chemicals

Viscosity Index Improver

Viscosity Parameters

Measure of a fluid's resistance to flow. It is ordinarily expressed in terms of the time required for a standard quantity of the fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid. Since vis

Viscosity Index (VI) Parameters

The measure of the rate of change of viscosity with temperature. Heating tends to make lubricants thinner, cooling makes them thicker. The higher the viscosity index is on a particular fluid, the less of a change in viscosity there will be over a given te

Viscosity Index Improver (VII) Chemicals

Additive to improve or increase the viscosity index. A VI improver increases an oils resistance to thinning as it is heated. It is commonly used in multi-viscosity or multigrade oils. Since a VI improver increases the viscosity as well as the viscosity in

Viscosity Modifier Chemicals

See V.I.I. Additive, usually a high molecular weight polymer that reduces the tendency of an oils viscosity to change with temperature.

VLS Industry Associations

Verification of Lubrication Specifications is an independent trade organisation providing a credible and trusted means to verify lubricant specifications. VLS aim to bring transparency to the lubricant market place and protect and educate end users.

Volatility Properties

That property of a liquid that defines its evaporation characteristics. Of two liquids, the more volatile will boil at a lower temperature, and it will evaporate faster when both liquids are at the same temperature. The volatility of petroleum products ca

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