The meaning of viscosity and oil viscosity

Document Type:Research Paper

Subject Area:Engineering

Document 1

The meaning of viscosity and oil viscosity? To understand viscosity you should imagine how different liquid flow in the pipe. For example, honey flows faster than water in a pipe. Which mean water has low viscosity but honey has high viscosity. Viscosity is the physical property of the liquid. By that viscosity is a measure of a fluid resistance to flow and shear. It describes the internal friction of a moving fluid. Viscosity is important to the engine life because it determines how easily the oil is pumped to the working components, how easily it will pass through the filter, and how quickly it will drain back to the engine. The oil’s viscosity is defined in the main by the size of the molecules.   The larger the molecule structures, the thicker, or higher, or heavier the viscosity. The size and structure of mineral oil molecules vary, so the average molecule size dictates the viscosity, whereas the synthetic oil manufacturing process results in consistently sized molecules of an identical structure. What are the differences in oil engine? When it comes to engines then there are very many types giving the implication that for each and every engine there is a type of oil engine. The three major types of engine oils are:- • Synthetic oils • Synthetic blends • High mileage • Conventional oil The molecules of synthetic motor oil usually have a shape that is more uniform in shape and that has very fewer impurities and the type of properties it has are usually very good and better as compared to conventional oil molecules.

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In terms of performance of the temperature, synthetic oil usually has a more and higher performance as compared to the other types of oils. This is because synthetic oil usually has a higher formula with perfuming additives, (Scherer 94) Synthetic blend motor oil is a type of motor that in action actually uses a mixture of synthetic and conventional base oils and this helps in the addition of resistance to oxidation. When it comes to low-temperature provision then the synthetic oil is the best. Late model vehicles usually have a preference for the high-mileage oil as it is formulated to that kind of vehicles. The high mileage motor oil usually has some unique additives of the used formula that usually aids in the burn–off of oil, and also helps in the prevention of leaks that may occur in the engines that are older, (Nesbit 54).

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There are a number of viscosity grades and the conventional motor oils can also be formulated into this, and the quality levels are usually very different. The drivers with simple car engines are usually advised to use conventional motor oil more often. What is the number 5W-30 mean in oil engine container? Looking at 5W-30, we got two sets of numbers 5W and 30. The reason behind the oil is tested at 100C because that considered a working temperature for the average engine. Which is the best grade oil for use in my motor? Put that question to a group of “knowledgeable” motorheads and the fur will fly. Pronouncements of doom and direct consequences will abound, usually supported by half-truths, urban myths, and anecdotal experiences giving rise to a general atmosphere of fear, uncertainty, and doubt (FUD).

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A good understanding of the information presented above will help dispel much of that FUD and aid you in making a well-informed choice. In general, you are best served to simply follow the recommendations of the engine manufacturer, (Farndon 32). For more detailed data on a specific oil, you need the oil manufacturer’s data sheets, (Farndon 32). These data sheets are readily available from most manufacturer’s websites and contain some of the actual SAE test results for that specific product. Let’s consider a common situation as an example and see how it might be analyzed. What do the SAE numbers on a container of motor oil mean? SAE J300 Motor Oil Specification (ca. SAE Grade Flow Rate @100° C 10 <= 14 seconds 20 15 to 24 seconds 30 25 to 34 seconds 40 35 to 44 seconds 50 >= 45 seconds To properly answer that question a bit of history is required.

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A major change was made in 1952 when the original set of grade designations was augmented with the addition of a set of winter (“W”) grade designations (10W, 15W, 20W, 25W, 30W) which were specified by viscosity measured at 0° F. This change was instituted to address problems with cold weather oil performance. Engineers and consumers alike had come to realize that the existing grade specification did not adequately describe the cold weather nature of existing motor oils. At freezing temperatures, an oil meeting specification SAE 20 refined from aromatic black Gulf crude was much thicker than an SAE 20 refined from light amber Pennsylvania crude. Engineers began to measure this difference in behavior with a viscosity ratio metric called the Viscosity Index (VI).  Oil.

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