To understand lubricating oils, you need to understand their two fundamental components –base oils and additives. Join us in the first part of a three-part introductory primer on engine lubricants, as we take a closer look at their base oil component – the different base oil types, their manufacturing processes, and their impact on the final lubricant properties.
Engines drive activity. To keep this “heart” of activity running smoothly and efficiently, the engine requires the right lubrication and protection, under various and all types of conditions. Lubricants have five main functions:
Regardless if you’re a seasoned pro in the industry or a new aspiring talent, below is a quick refresher on the basics of base oils – their different types, manufacturing processes – to help explain their importance in determining the final lubricant properties.
Key Lubricant Performance Characteristics
Engine oils are slightly different from the broader category of industrial oils due to their characteristics. Here’s a quick table to break them down:
Low temperature rheology
Protection against wear
Protection against corrosion
Inhibition against rust
Reduce deposit formation
What is a Lubricating Oil?
Engine/lubricating oils are made of selected base oils combined with performance-enhancing additives.
In today’s lubricant landscape, the base oil / basestocks used in engine oils are usually divided into two general categories – mineral or synthetic.
Mineral base oils are distilled from crude oil in a conventional refinery, resulting in oil molecules of non-uniform sizes.
Synthetic base oils, on the other hand, are chemically engineered from pure petroleum gases in a chemical plant, or converted from crude oil via severe catalytic hydroprocessing.
These two base oils are subsequently divided into 4 major classifications below. Base oil composition has a significant effect on the overall performance of engine oil. A blend of base oil types is often used to balance performance vs costs.
· API Group I
· API Group II
Highly refined mineral oil
· API Group III
Very highly refined mineral oil (commonly referred to as Synthetic)
· API Group IV
Chemically built, i.e. synthesized
PAO = PolyAlphaOlefin
Composition Differences between Basestocks
2,000 – 7,000
10 – 300
1 – 5
15 – 30
1 – 10
95 – 119
120 – 130
120 – 200+
How Basestocks are Manufactured
Properties of a PAO in an Engine Oil
What this means?
High viscosity index (VI)
Requires less VI improver, thus less deposits
Reduces ring stick and bore polish
Engine oil is more likely to stay in grade
Lower oil consumption and emissions
Lower fire hazard
Low pour point
Better low temperature fluidity (pour point -57⁰C)
Better starting performance, which reduces wear
Longer drain intervals
Lower levels of sludge, deposit, and varnish
Costs approx. 4 times more than mineral base oils
Additives need to be specially selected
Oil is prone to attack seal materials
Overall, synthetic lubricants typically provide more robust performance, especially in terms of low temperature pumpability. high temperature stability, and protection against deposits. These attributes can help towards reduced engine wear, fuel economy potential and long engine life.
Synthetic lubricants can also significantly improve fuel economy, working much more quickly than mineral engine oils, so the engine reaches peak operating efficiency that much sooner.
Especially in this day and age, importantly, another advantage of synthetics is that they’re cleaner and environmentally friendlier – helping to cut engine emissions when compared to conventional mineral engine oils. Conventional mineral engine oils also contain greater amounts of impurities, such as sulfur, reactive and unstable hydrocarbons, and other undesirable contaminants that cannot be completely removed by conventional refining of crude oil.
To maximize the benefits of the engine oil and minimize any issues, we strongly recommend businesses to speak with their lube distributor and expert to evaluate and identify the best engine oil most appropriate for their use, as well as the optimum practices to extend its longevity.
In the second part of our primer on engine oils, we’ll talk about what are the different types of additives, why they’re important, and why we need to balance the amount of additives in lubricant formulation.
Do you have any questions about the role of base oils in engine oil? Share them with us in the comments below, or hit “Like” on the toolbar on the right if you found this refresher useful!
Thank you for this. This helps me understand more about base oils.
Very useful information! Basic oil plays an important role!
It is the basics of lubrication. Basic is very important for us. Superb .
The Mobil product and the Third party product is same group II mineral oil, Please tell me that How do I know the Mobil product is better?
This is very useful! thank you!
Very complete and very well explained.
Sir what will be the % of reducing friction when we have to go from Mineral Base oil to synthetic base oil in Engine.
Alkylated naphthalenes are a very interesting topic. I can try translating materials from ExxonMobil Chemicals. I can’t promise when, but I’ll try to prepare something.
Good article, concise and helpful. I would like to know more about the various types of synthetics (PAO, esters, alkyl naphthalenes, etc.) manufactured by ExxonMobil. What their advantages, features, disadvantages are compared to base oils from other manufacturers. And what the volumes of their production are and their share in the world is.