1) density
Density is the physical properties of petroleum and its products, the most simple, the most commonly used, it refers to the prescribed temperature unit material contained in volume in the quality, unit: kg/m3
Because of the different temperatures, variations in density, high temperature measured density than low temperature measured density of small. For comparison, the general density is used to the prescribed temperature density representation. China's GB regulations, at standard temperature (20 ℃) under the density as the standard, the density of g/cm3. Density is important in the production and transportation, are used in the product design process measurement, refinery. To some extent, can determine the general quality of oil, density are also used in the measurement conversion quantity, delivery acceptance. Simple judgement oil property, according to the density estimated crude oil types, such as paraffin containing more often than the density of crude oil containing naphthenic hydrocarbon and aromatic hydrocarbon of crude oil with low density. Sulfur, oxygen, nitrogen and more and more colloid and asphalt oil density is higher.
The density of oil varieties: gasoline P = 0.7-0.76g/cm3 0.77-0.84g/ kerosene oil cm3 0.87-0.89g/cm3
Density can be approximated estimation of oil quality and chemical composition changes, especially in the process of storage and transportation, such as found in some oil density increased or reduced, can determine whether the mixed heavy oil or light oil.
2) viscosity
Important physical and chemical index of lubricating oil viscosity is, of all kinds of lubricating oil classification, quality identification, identify crucial design purposes, is indispensable in the process of physical constants calculation. Liquid, semi fluid state material in the action of external force, while the flow when the internal friction between molecules or internal resistance.
We and the international practice, using the kinematic viscosity of m2/s, mm2/s in the actual production of the relationship between the two is 1m2/S=106mm2/S (crude oil)
Lubricating oil viscosity changes with temperature, as the viscosity temperature, average temperature, reduce viscosity, temperature, the viscosity increases, the viscosity ratio refers to oil in two prescribed temperature measured by the low temperature viscosity and high temperature viscosity ratio value of China. And the international ISO standards, using 40 and 100 ℃, viscosity index refers to the characteristics of oil viscosity with temperature changes in a prescribed value, higher viscosity index, oil change little with temperature, the table can be found. Then what is the significance of viscosity of oil production and use?
(1) increase in viscosity of engine, will affect the power, the viscosity is too low will cause difficulty in starting, supporting capacity of oil film to reduce.
(2) the majority of lubricating oil are divided according to the viscosity of lubricating oil is used a basis.
(3) the viscosity cooling effect is poor. Because of the circulation speed is slow, the filter is less, washing effect is poor.
(4) the viscosity of the oil, the oil film rupture.
(5) the sealing effect is not good.
(6) increase the consumption of lubricating oil.
3) oil
Oily oil grease friction reducing properties of adsorption on the surface of metal, improve the fuel performance, security and wear and friction coefficient of the lowest minimum. These additives are generally polar molecules, can be directed to adsorb on the metal surface, forming a strong oil film, can bear high strength. But not as extreme pressure effect. Extreme pressure lubrication is generally high temperatures, will reduce the adsorption of polar molecule force. Oily agent is usually associated with other additives such as antioxidant, anti rust composite for spindle oil, hydraulic oil, rail oil, so the general low load adding oiliness agent, to ensure adequate lubrication agent effective, high temperature, high load of oily agent almost no what effect, and the anti-wear and extreme pressure agent in low temperature, low load instead. Wear increased.