What Should You Put in Your Engine
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While fuel plays a significant role in making your car move as fast as it does, it is the engine oil that allows your engine to utilize those fuels.
Engine oils are used in most motor vehicles and appliances to reduce friction, disperse the internal heat, and prevent corrosion. When you buy a car or a motorcycle, the manufacturer fills it up with ample engine oil before delivery. This oil can get thicker with use and you would need to change it regularly.
However, selecting engine oil is hardly straightforward. Engine oils come in a variety of types, grades, properties, and prices. As an owner, you will need to choose the right engine oil, which meets your engine’s needs. While engine oils have evolved over time, the core components that make up engine oil remain the same.
Materials Used in Engine Oil
Engine oils are essentially made from base oil, with viscosity enhancement additives, among other chemicals that are blended to enhance and add to the functionality.
- Base Oil
Base oil or base stock is a mix of several different types and grades of oils. The mixture ensures that engine oils have the required viscosity while enhancing and increasing their properties. They are transparent, comprising 90% of the final engine oil. Base oil, by itself, provides the minimum essential level of lubrication. Additives are added to enhance this further. Base oils are grouped into five types based on the refinement level, with Group 1 being the least refined and containing maximum sulfur, and Group 4 being the most refined and stable. Group 5 comprises other oils including bio and ester-based oils.
- Viscosity
It is the thickness of oil. In order for your engine to function effectively, the engine oil needs to be thick enough to remain on the surface of the engine to lubricate it. Viscosity determines the grading of the oil as well as its uses. Additives like viscosity index improvers and viscosity modifiers allow the oil to flow through smoothly during peak summers and winters.
- Additives
They help to improve the performance and functionality of engine oils and comprise 10% of the resultant oil. They give engine oil its distinct dark yellow, amber color. Additives are segregated into four categories depending on the role they perform.
Enhancement agents improve the oil’s performance and comprise lubricity modifiers, pour point depressants, viscosity modifiers, and viscosity index improvers. Some agents increase the functionality of oil, such as the detergents, dispersants, and anti-wear agents. Preventative agents reduce the effects of the harmful components of the oil. They include oxidation inhibitors, anti-foam, anti-mist, and corrosion inhibitors, among others.
Process of Manufacturing Engine oil
Base oil refinement process
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All base oils start as a form of crude oil or petroleum. These need to be processed and distilled through several stages to convert them into engine oil for sale. Each step of production cleanses and distills the base oil to reach the specific viscosity and purity of lubrication oil. The industrial process can be broken down into the following procedures.
- Deasphalting
This process is also called sedimentation. It uses propane as a medium to separate distilled oil into two products. Tar and similar compounds with high boiling points settle at the base as residue and deasphalted oil.
- Removal of aromatics
This process is also called ‘solvent extraction.’ The method uses liquid-based solvents to separate impurities and aromatic components of the oil. The resultant product is called neutral oils. After this stage, oils become denser and chemically stable.
- Dewaxing
This process separates the wax component in oil. The oil obtained, after that, is more resilient to lower temperatures. For most engine oils, the stock oil so obtained, is used as the base oil.
- Finishing
It is the last step in refining base oils and is also called “Hydro-finishing” as the process involves Hydrogen. In this process, extreme temperature and pressure conditions are used to change the base oil’s polar compounds. The process makes the resultant product lighter and more stable. Hydro-finishing plays a significant role in determining the quality of the finished base oil.
- Blending
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The Process of Oil blending
The process of blending oil is a crucial and simple one.
A limited quantity of base oil is poured in a blending vessel and heated.
The heated oil allows additives to mix faster, while ensuring a more chemically stable product. After that, additives are added in pre-determined quantities in a specific order. The mixture is mechanically stirred for an even consistency.
Since certain additives can be immiscible, high-shear and low-shear blending is utilized. Shear blending uses a high-speed rotator and a stationary tank to allow substances to mix. High-speed shears create tension and break difficult substances to power the procedure.
In contrast, low shear blending is more suitable for delicate additives that tend to break down due to high pressure. It uses uniform pressure and flows to blend in fluid additives.
- Inspection and packaging
A small sample of the produced engine oil is sent to a testing lab. The oil gets assessed to ensure that all necessary properties like viscosity, fluidity, flash point are as per the pre-determined terms.
Finally, the approved oil batches make it out and find themselves at an automated unit for packaging. Nowadays, polyethylene jugs are used though many manufacturers are exploring the possibilities of flexible packaging like pouches.
With decades of research and technological advancements, performance additives have become an integral component of engine oils.
Chemical Additives in oil
Depending on their properties, here are some of the most frequently used additives:
- Pour Point Depressants
In colder areas, the engine oil can start to thicken due to wax particles, requiring more energy to keep it flowing smoothly through the engine. It adds to the engine’s stress and decreases its efficiency dramatically. The pour point depressants are additives, which help reduce the wax’s freezing temperature, allowing the oil to flow easily at lower temperatures.
- Viscosity Modifiers
These are polymer-based additives, and though we have discussed them earlier, let us further dig into their composition. Due to their large chemical structures, they keep the oil sufficiently thick at higher temperatures. This thickness allows them to remain stuck on the engine’s surfaces, which helps lubricating around instead of flowing down. They are also temperature-sensitive to maintain flow at high as well as low temperatures.
- Oxidation inhibitors
They help increase the life of the oil. Oxidation is the main reason oils can break down and become less effective over time. Additionally, these oxidized oil stick to the engine’s surfaces, forming sludge and slowing it down. These additives reduce the sludge formation and keep your engine in good health, letting the oil stay active for a longer duration.
- Detergents and dispersants
Sludge particles comprising dust, metal pieces, and oxidized components of oil can start to build up over time, which reduces speed. Detergents help clean those layers of micro-particles and waste deposits as the oil flows by.
- Corrosion Inhibitors
Since corrosion occurs due to high levels of acidity in the oil, these additives are alkali-based and keep the pH high, which helps restrain rust.
- Anti-wear
These agents contain solid oil particles. When an engine starts, they form a layer on the moving parts to decrease friction, allowing smooth movement. They are primarily used in mineral-based oils.
- Anti-freeze
Instead of thickening, these additives decrease the heating temperature of the oil. The change allows oil to retain its fluidity and flow easily at lower temperatures.
Despite the overwhelming benefits additives provide, it is the source and kind of base oils that helps determine the type and price of different engine oils.
Types of Engine oil
Engine oils are classified based on the composition of base oil. These are the four categories of engine oils:
- Mineral/ Conventional Oil
They are made of petroleum-derived base oils. They were the first engine oils produced. Despite significant advancements and improvements over time, they continue providing essential lubrication and protection against wear. They are not so heavy on the pocket too, especially if you compare them with regular modern engine oil. However, they are not suitable for very high-temperature conditions and need to be replaced very often.
- Synthetic Engine Oil
It is the latest and the best variety of engine oil in the market. Synthetic oils are created in labs using special processes to retain only the best molecules. The blends, therefore, are purer and highly controlled for the most efficiency. They may or may not be derived from mineral oils. The refining process for synthetic oils is also complicated. It involves selective modification of molecular structures of the hydrocarbons that make up oil. The changes allow the oil to remain consistently fluid and active despite temperature changes. They are less resilient to break down and remain in use for a long time. They are also the most expensive variety of oil.
- Semi-Synthetic Engine Oil
They are a blend of mineral and synthetic oils. However, the composition of the final product can have vastly different amounts of both. Engine oil with merely 1% synthetic blend is also called semi-synthetic oil. They are cheaper than synthetic oils and offer many of their features, like fluidity at cold temperatures and more protection against wear. They are also more stable than mineral oils and need to be changed less often.
- Bio Oils
Bio engine oils
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These are natural oils derived from plant and animal sources. They were in daily use prior to the discovery of petroleum-based lubricants. However, with the push for more sustainable living, the interest in bio-based oil has been growing.
Since 1996, canola-based oils, alongside other plant and animal-based oils, have been produced and tested. They are not only biodegradable, non-toxic, and do not accumulate in marine organisms, but they happen to be just as powerful as conventional oils.
Several companies like Green Earth Technologies sell bio-oils for engines.
Now that we have already seen the general composition and types of engine oil, we will now see the quality and grading of engine oil which determines its use.
Quality and Grading of Engine oil
When sold, the grading of the oil depends on its viscosity. Society of Automotive Engineers (SAE) established the grading system, which is still being followed by oil manufacturers. The digits and letters you see on oil jugs are these grades, classifying engine oil for specific uses.
These are two methods of classification used by the SAE
- Single grade
Also called ‘straight weight oils,’ they are oils without viscosity index improvers or viscosity modifier additives. SAE’s system establishes 11 grades of oils in this category. Of these, six are suitable for use in winter and cold areas. They are marked ‘W.’ The flow of winter oil is measured at different temperatures using two methods to find the coldest possible temperature oil can flow at. This temperature defines the grade of the oil, with lower grades showing high tolerance for cold climates.
For non-winter oils, the flow is measured at the standard temperature of 100 °C. The resulting rate of flow defines the SAE grade. Here, higher grades reflect a higher viscosity.
- Multigrade Oil
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They make use of viscosity-improving additives. Such additives allow them to remain fluid at a wide range of temperatures. They are also called ‘all-season oil’ since their wide operating range allows the engine to function effectively in the lower temperatures of winter just the same as they would in the higher temperatures of summer. These oils, likewise, have two grades. With ‘W’ at the end, the first grade marks the viscosity at lower temperatures while the second grade reflects the consistency at 100 °C. There is a danger of these oils breaking down in motorcycles. Hence, motorcycle-specific oils are recommended.
Conclusion: The Future of Engine Oil
Having seen all the factors that go into the making of commercially available oils, it becomes easier to estimate what kind of oil will allow your car to run smoothly. Engine oil, at present, is a vital purchase for all car owners who want to extend the life of their cars.
There has been speculation that the electric vehicle industry may be forcing engine oils into redundancy. With electric transport offering more sustainable systems and cheaper repair and maintenance, the demand for engine oil is showing signs of slowing down. However, like all changes, this process is slow as well.
Another change that is steadily gaining traction is more research into engine oils. Sustainability-minded leaders and corporations are coming together and working to make plastic-based engine oil a reality. The idea is to break down the contents of disposed plastics to convert them into this wax-like lubricant. Further, researchers are working on bio-oils to reduce lead burn and make engine oils nature-friendly.