Today’s vehicles continue to get more and more sophisticated. They must in order to meet the needs and expectations of customers and to keep pace with government regulations for fuel economy and emission control. Since the demand for horsepower does not diminish, automakers are designing engines that are smaller and lighter weight yet packed with power. Oil manufacturers work hard to produce motor oils capable of keeping up and enhancing your engine’s performance.
What’s the meaning of motor oil?
Motor oil has often been called the “lifeblood” of an engine for without it an engine cannot function. Oil is the lubricant that keeps all of the moving parts inside your engine moving. It works by providing a thin and slick coating between components that rub against one another – like the pistons and the cylinder walls. The oil prevents those parts from actually touching one another, reducing friction, eliminating wear, and helping to cool your engine.
To accommodate all types and sizes of engines, motor oil comes in different grades or viscosities. Viscosity describes the thickness of a liquid, its ability to resist flowing. Honey has a high viscosity, while water has a low viscosity. Oil is somewhere in between.
Oil viscosity is assigned a “grade”, 30 weight, 40 weight, and so on. SAE30 is an example of a straight-weight (or straight-viscosity) oil. Straight-weight oils were used many years ago in most vehicles but are now used rarely in automobiles. Contrast that with multi-weight or multi-grade oils that perform one way when cold and another when warm. The terms 10W30 or 5W20, where the first number represents its cold ability (“W” is for winter) and the second number is its rating at operating temperature, are commonly found on the auto parts store shelf.
The viscosity of oil drops as its temperature rises. It gets thinner as your engine heats up. So oil manufacturers design products that resist that tendency. A low-viscosity oil is infused with additives that essentially raise the viscosity as temperatures go up. But, because the oil wants to thin out, those additives actually serve to keep the oil at a consistent viscosity across a range of temperatures. For instance, 10W30 is a grade 10 when cold. But as it heats up, it acts as a grade 30, which (when warm) should have similar characteristics to the grade 10. The lower grade/viscosity when cold allows your engine to crank and start more easily, and the higher-grade characteristics resist viscosity breakdown when hot.
Conventional versus synthetic motor oil
If you are like many drivers, when you consider motor oil, you are likely thinking about conventional oil that is derived and distilled from crude oil. Conventional oil is widely used and relatively inexpensive. It does the job of coating engine parts to protect against friction and wear. It does, however, have a tendency to break down chemically and to leave dirty deposits in your engine if you are not careful.
Because conventional motor oil is made directly from crude oil pulled from the ground, it contains unwanted compounds that act as impurities. As conventional oil ages with use, its ability to maintain a consistent viscosity diminishes. It begins to sludge up and fails to flow as it should. Manufacturers work to ensure the best possible function of their products, but these impurities can clog up your engine and form coatings on engine parts if you are not religious about oil maintenance.
Synthetic motor oil is an option for some auto owners. It is a necessity for others. But what is synthetic oil? Synthetic oil is created artificially through a complex process to produce consistent molecular size and shape. It begins with highly-refined crude oil (or some other compound) as a base stock to which additives are built-in. This type of oil is manufactured to exact specifications by oil makers who hold the secrets of their formulations close to the vest.
Advantages of synthetic oil
Synthetic motor oil boasts several advantages over conventional oil. Because synthetic oil is made up of molecules of consistent size and shape, it allows for less friction inside your engine. And because it is highly refined, it has fewer impurities that can form engine deposits and sludge. Additives in synthetic oil help to boost engine protection and serve to clean internal engine surfaces.
Synthetics perform better than conventional oils in extreme temperatures, are subject to less viscosity breakdown, and are more stable. They also provide longer engine protection and longer intervals between oil changes – sometimes as long as twenty thousand miles. But even if you change your oil just as frequently with synthetic as you would with conventional (a costly proposition since synthetics are significantly more expensive), your engine receives better potential protection.
So, in a nutshell, what are some benefits of synthetic oil over conventional?
- Minimized friction due to uniform molecular size and shape
- Less engine wear
- Reduced engine deposits because of increased refinement
- Improved protection and cleaning
- Less sludge buildup
- Better performance in the cold and extreme temperatures
- Longer intervals between oil changes possible
But another advantage of synthetic oil, one that makes it not optional but necessary for many engines today, is its ability to be made in lower viscosities than conventional oil.
Conventional motor oil is available in a range of multi-grade options to suit many vehicles on the road today. But because of its makeup, conventional oil cannot be found for really lightweight applications. Modern engines are engineered with ever-tighter tolerances, smaller gaps between their moving parts than those of the past. The tendency has been toward smaller, lighter engines that still produce significant horsepower. Those tighter tolerances and high-performance expectations call for lighter-grade oils.
There was a time when almost every car on the road could be filled with straight and thick thirty-weight oil. Along came multi-grade (multi-viscosity) oils, but still, most cars used 10W30. As engines got smaller, some might call for 5W30, but that was not common for quite a while.
But today? 5W30 is no longer a lightweight oil. Many engines call for 5W20, 0W30, or even 0W20 grades. Extremely lightweight oils can only be made synthetically. So many vehicles have synthetic oil straight from the manufacturer and require that synthetic oil be added with each oil change.
Advances in synthetic oils
As engine technology continues to advance, so does lubrication technology. Oil manufacturers strive to formulate high-performing lighter-weight oils that are vehicle specific. Complex test procedures are designed to validate new formulas. The chemical compound makeup in oil formulas is altered to allow for better stability, resistance to viscosity breakdown, and less oxidation in the oil.
Recent goals of oil makers include ways to help auto manufacturers meet fuel economy and emission control demands. Small yet powerful engines can help by reducing vehicle weight. But, besides the need for lightweight oils to accommodate tight engine tolerances, other problems with small and light engines need to be solved.
For instance, in the competition to build the most fuel-efficient engine, auto manufacturers are designing small direct-injected gas engines. These engines have the power of a larger engine, but are much more compact and lightweight, bringing down the overall vehicle weight and saving on fuel consumption.
But smaller engines are often equipped with turbochargers, variable valve timing, and/or direct injection to accomplish high power and torque along with improved fuel economy. Unfortunately, there is a downside: an undesired tendency toward a phenomenon called low-speed pre-ignition (LSPI). Occurring especially at lower speeds and when high torque is called for, LSPI is spontaneous combustion early in the combustion cycle that leads to engine knock and possible engine damage. The quality of synthetic base oil and the inclusion of the right compounds and detergent additives play important roles in preventing LSPI and are a focus of the oil industry.
Other advances include formulations to further help in reducing engine deposits, reduce greenhouse gasses, and improve fuel economy. Some automakers are even designing engines that can operate on oils with viscosities as low as 0W16. That sure is a far cry from the honey used decades ago.
Columbia Auto Care & Car Wash | Author: Mike Ales | Copyright January 2020
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