LUBRICATING OIL: What no one is talking about.


Lubricating oil used in engines must act as lubricants, coolants, and a vehicle for removal of impurities.  

It withstands high temperatures, does not break down, and has a long life.  

Engine development trends for higher operating temperatures, faster & tighter tolerances are rapidly increasing.  

All of these require improved oils compared to those just used years ago.  

Of course, the technology of the oil industry must continue with technological growth in engines and fuels. 

Early engines and other mechanical systems are often designed for the use of lubricating oil.  

There is a need for a continuous supply of fresh oil.  

Used oil was burned in the combustion chamber or dropped to the ground.  

Only a few decades ago there was a tolerance between the piston and the cylinder wall as the engine burns the oil that has penetrated from the crankcase over the pistons.  

This required regular oil refills and frequent oil changes with blow by contamination of the remaining oil.  

The HC value in the exhaust gas was high due to the oil in the combustion chamber. 

The rule of the 1950s and 1960s was to use oil in your car after every 1000 km.  

Lubricating oil

Modern engines run at higher temperatures, tighter tolerances to keep oil consumption low, and smaller oil pans to save space.  

They generate more performance on smaller engines by running faster and with higher compression ratios. 

This means a higher force and a greater need for good lubrication.  

At the same time many manufacturers now offer to change the oil every 6000 miles. 

Not only the oil will last longer in very harsh conditions, but no new oil will be added between oil changes.  

Engines of the past that consumed some oil required periodic makeup oil to be added.  

This make-up oil is mixed with the rest of the used oil and improved the overall lubrication characteristics of the engine.  

Modern engine oils need to work in extreme temperature ranges.  

Must rise from cold engine starting temperature beyond the extreme steady-state temperatures that occur in engine cylinders.  
Oil should adhere to the surface as they always lubricate and provide protection against corrosion.  

This is often referred to as oiliness.  

Oils must have high film strength to ensure metal-to-metal contact under extreme loads.  

The oil must be non-toxic and non-explosive.  


The use of lubricating oil is as follows: 

1. It should reduce friction and wear. Improves engine efficiency by reducing frictional forces between moving parts.  

2. Coolant. 

3. Removal of impurities.  

4. Improved ring seal and reduced blow-by.  

5. Slow corrosion. 

6. Stability over a wide temperature range.  

7. Long life.  

8. Inexpensive. 

The basic component of most lubricants is the hydrocarbon component from crude oil. 

These are high molecular weight chemical species obtained from the distillation process.  

Various other components are added to create a lubricant that allows for maximum engine performance and longevity. 


These additives include:  

1. Antifoam agents 

These reduce foaming that occurs on crankshafts and the components rotate at high speed in the crankcase oil sump.  

2. Oxidation inhibitors 

When bubbles are formed, oxygen is trapped in the oil and can oxidize engine components. 

One such additive is zinc dithiophosphate.  

3. Pour-point depressant. 

4. Antirust agent. 

5. Cleaning agent. 

These are made from organic and metallic salts.  

They help to keep debris floating and prevent reactions that form varnish and surface deposits.  

They help neutralize the acid formed from the sulfur in the fuel.  

6. Anti wear agents. 

7. Friction reducers agent. 

8. Viscosity index improvers. 

Lubricants are generally evaluated on the Viscosity Scale of the Automotive Engineering Association (SAE).  


Dynamic viscosity is defined by the following equation: 

Ts = /-t (dUjdy)  

 Where, Ts = shear force per unit area. 

/-t = dynamic viscosity. 

(dUjdy) = velocity gradient. 

The higher the viscosity value, the greater is the force needed to move adjacent surfaces or pump oil through the passage.  

Viscosity is highly temperature dependent and increases as the temperature drops.  

In the temperature range of engine operation, the dynamic viscosity of the oil can vary by more than an order of magnitude.  

The viscosity of oil also changes with shear and dUjdy, decreases with increasing shear.  

Shear velocities in the engine range from very low to very high values in the bearings and between the piston and cylinder walls.  

The change in viscosity due to these extremes can be several orders of magnitude.  

The common viscosity grades used in engines are:  


SAE 10  

SAE 20  

SAE 30  

Oil with a small number has a low viscosity and is used in the cold season operation.  

The larger the number, the higher the viscosity, and it is used in modern times.  

High temperature, high speed precision tolerance motor.  

If the oil is too viscous, more work will be required for pumping and shearing between moving parts.  

As a result, friction work has increased and braking work has decreased.  

And power output fuel consumption can increase by up to 15%. Start-up cold engines lubricated with high viscosity oil are very difficult (e.g.) 20 °C or 100e lawn mower). 

Multigrade oil was developed to have a more constant viscosity over operating temperature range of the engine. 

When a specific polymer is added to oil the temperature dependence of oil and oil viscosity decreases.  

These oils have low viscosity values and increase in viscosity when cold. 

Values like SAE LOW 30 are oil characteristics of 10 viscosities in cold weather (W = winter) and 30 viscosities in cold weather hot.  

This makes the viscosity more constant over the operating temperature range.  

This is very important when starting a cold engine if the oil is cold, the viscosity should be low enough to start the engine without much difficult.  

Oil flows with less resistance and the engine spins for proper lubrication.   

It is very difficult to start a cold engine with high viscosity oil as the oil resists the rotation of the engine and is poorly lubricated.  

This is because it is difficult to pump up the oil.  

On the other hand, in case of the engine oils with high viscosity are desirable up to the operating temperature.  

High temperature reduces viscosity, low viscosity oil does not reduce viscosity provides proper lubrication.  

Some studies have shown that polymers added to change viscosity are not very lubricious.  
When using SAE 30 oil, starting a cold engine is very difficult, it is poorly lubricated before the engine warms up and causes very high wear.  


Heavy fuel oil and lubricants are the most common types of petroleum used in the marine industry. 

Modern ship waste fuel is an economically important fuel used worldwide in commercial transportation.  

Modern (since the 1970s) heavy fuel oils, once a simpler fuel consisting primarily of atmospheric residues, heat and catalytically decompose gas oils or other highly refined atmospheric and vacuum residues. 

It is mixed with a purified intermediate (usually of low grade).  

The manufacturing complexity and economics of modern heavy fuel oils have resulted in highly chemically diverse heavy fuel products that could be useful in chemical fingerprinting of oil spills.  

The gas chromatographic “fingerprints” of these fuels are often characteristic, with the major components of the aromatic gas oil range (C10 – C25) and the residual range components of the wide boiling point (C25 – C45 Is mixed.  

It is mainly composed of UCM and various amounts of dissolved paraffin and PAH.  

Thus, heavy fuel oils unique gas chromatography “fingerprint” could be used as a reliable indicator of oil spill research. 

In particular, it can be used in the early stages of oil spills before significant weathering occurs.  

However, the “fingerprint” of heavy fuel oil gas chromatography changes with weathering after the oil spill and ultimately confuses the use of simple qualitative chromatography comparisons in identifying and tracking oil spills.  

Coincidentally, this has shown that the detailed molecular chemistry of heavy fuel oil, including petroleum biomarkers and PAHs, is very diverse.  

That is, use oil spills and source correlation analysis.  

Lubricants are used in the shipping industry (and others) for a variety of purposes, including lubrication of engines and gearboxes.  

To reduce friction on the metal surface of the motor drive shaft and motor.  

It is equipped with hydraulic winches, cranes and other heavy equipment for operation.  

Lubricants are highly refined, high boiling point petroleums with unique and easily identifiable chemical properties.  

One of the most notable chromatographic features is often the mostly Gaussian UCM (unresolved complex mixtures), with few significant separation peaks.  

This characteristic UCM (unresolved complex mixtures) can occur over the entire C15-C45 + carbon range, but the exact range and maximum carbon value will vary from lubricant to lubricant depending on the oil formulation.  

Therefore, the shape of the UCM (symmetry, width, and tip) is an important diagnostic characteristic of various lubricants.  

Lubricants are highly refined and certain hydrocarbon compounds, especially Nalcan and PAH compounds, are rarely found in fresh (unused) oils or have significantly reduced concentrations. 

Traditional PAH fingerprints are useful for investigating spills from used lubricants, as the levels of PAHs in the lubricant can rise dramatically during use. 

In our experience, most of the PAH in spent lubricants from ships and offshore petroleum platforms comes from trace amounts of unburned fuel [for example, most petroleum biomarkers (terpan and sterane)].  

In general, lubricants are clearly due to removal / destruction during base oil refining.  

The biomarker Chemistry, combined with a UCM profile and basic analysis of PAH, provides legal chemists with the best way to identify and track sources of lubricating oil in oil spill studies.  

Combined with the use of appropriate forensic chemistry techniques and knowledge of refined chemistry of HFOs and lubricants and their behavior on water, oil spill investigators can safely identify and track the fate of oil spills in the environment.  


It is very economical. 

Lubricating oil is a long-term protection of equipment. 

It increases mechanical reliability. 

Accurate lubrication. 

It reduces maintenance costs. 

Increased profitability. 


Poor self-healing properties.  

Poor heat dissipation.

Higher coefficient of friction and wear than hydrodynamically lubricated bearings. 

Color associated with solids may be undesirable. 

Difficult if not impossible to feed into a lubrication system. 

Storage or service life is limited. 


Lubricating oil is obtained from crude oil that has been pre-cleaned (precipitated) before being pumped to the fractional distillation tower.  

A typical high-efficiency fractionation tower, 25-35 feet (7.6-10.6 meters) in diameter and 400 feet (122 meters) high, is constructed of high-quality steel to withstand the corrosive compounds present in crude oil.  

It is equipped with an ascending row of condensate collection trays.  

In the tower, thousands of hydrocarbons in crude oil are separated from each other by a process called fractional distillation.  

As the vapor rises through the tower, the various fractions cool, condense, and return to liquid form at different rates determined by their respective boiling points (the lower the boiling point of the distillate, the more it rises before condensation). 

Natural gas reaches its boiling point first, followed by gasoline, kerosene, lubricants and tar.  

1. Sedimentation  

Crude oil is transported from wells to refineries by pipeline or tanker.  

Refineries settle oil to remove solid contaminants such as water, sand and rocks. 

Crude oil is pumped into a large storage tank where water and oil separate and impurities from the oil settle.  

2. Fractionation  

Next, heat the crude oil to about 700 degrees Fahrenheit (371 degrees Celsius).  

At this temperature, it decomposes into a mixture of hot steam and liquid, which is then pumped to the first of the two fractionation towers. 

Hot hydrocarbon vapors are floating here. 

As they cool, they condense and collect in different trays installed at different levels of the tower. 

Normal atmospheric pressure is continuously maintained in this tower, and about 80% of crude oil is vaporized.  

Next, the remaining 20% of the oil is reheated and pumped to the second tower.  

The vacuum pressure lowers the boiling point of the remaining oil, allowing it to vaporize at lower temperatures. 

3. Filtering and solvent extraction. 

4. Additives, inspection, and packaging. 

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