How to classify the level of engine oil?

Distinguish between oil grades:

The engine oil industry is divided by quality grade and viscosity grade, and the quality grade adopts the grade classification standard formulated by API. Viscosity grades are based on the grades established by SAE. Take Bangneng SN0W-40 fully synthetic engine oil as an example to analyze the engine oil grade.

First, viscosity index.

According to the SAE method, there are 6 types of oil for winter, 5 types of oil for summer, and 16 types of oil for both winter and summer.

1. Winter oil grades: OW, 5W, 10W, 15W, 20W, 25W. The symbol W represents winter, the smaller the number before W, the smaller its low temperature viscosity, the better the low temperature fluidity, and the lower the applicable minimum temperature.

2. Summer oil grade, 60. The higher the number, the greater its viscosity and the higher the applicable maximum temperature. Winter and summer general oil grade: 5w w w w w

The smaller the number for the winter portion and the larger the number for the summer portion, the larger the applicable temperature range.

Second, quality indicators.

According to the API quality classification, engine oil is divided into gasoline engine oil series (i.e., S series) and diesel engine oil system (i.e., C series), and the oil products of each series are arranged in alphabetical order (A, B, C, D, E, F), and are divided into several grades, and the lower the letter ranking, the higher the grade.

The oil grade is divided according to the quality grade and viscosity grade, the oil used in gasoline engines is usually indicated by the letter S, and the oil used in diesel engines is usually represented by the letter C. The composition of the engine oil is composed of base oil and additives, of which the base oil is the main component of the lubricant and determines the basic properties, and the additives can improve the deficiency of the base oil.

Engine oil can lubricate and reduce wear, assist cooling and cooling, seal leakage, rust and corrosion, shock absorption and cushioning of the engine. It is known as the "blood" of automobiles.

The oil label consists of two parts: grading and viscosity specification. The oil designation usually indicates viscosity and quality. The specific interpretation is as follows: the viscosity of lubricating oil is mostly marked by SAE and other grades, and SAE is the abbreviation of the English "Society of Automotive Engineers".

w stands for winter (winter), the more ** the number in front of it, the better the low temperature fluidity of the engine oil, the lower the ambient temperature available for use, and the better the protection ability of the engine during cold start; The number after the "W" (after a horizontal line) is an indicator of the high temperature resistance of the engine oil, and the higher the value, the better the protection performance of the engine oil at high temperatures.

The label after the classification of the engine oil indicates its viscosity specifications, for example, in "15w w-40", "w" means winter (winter), the more ** the number in front of it, the better the low temperature fluidity of the engine oil, the lower the ambient temperature available for use, and the better the protection ability of the engine during cold start, such as 5w represents the external low temperature resistance -30 °C, and the 20w low temperature resistance is -15 °, and the number behind the 20w low temperature resistance is -15 ° represents the kinematic viscosity of the oil at 100, the higher the value, the higher the viscosity. 40 represents 100 degrees Celsius, and the kinematic viscosity standard is between to, which is definitely not what some people say can be used below 40.

The oil classification is indicated using a two-letter combination. The series starting with "S" represents gasoline engine oil, the general specifications are from SA to SN (in alphabetical order, but there is no SI in it), each letter increment, the performance of the oil will be better than the previous one, and there will be more additives in the oil to protect the engine; The lower the letter, the higher the quality grade, and most of the oil grades in international brands are above the SF grade. The series starting with "C" represents diesel engine oils.

If the letters "S" and "C" are present at the same time, it means that the oil is a general purpose type of gasoline and diesel.

The viscosity and grade of lubricating oil products are confirmed internationally by the American Society of Automotive Engineers (SAE) oil viscosity classification (SAE) and the American Petroleum Institute's quality grade standard (API).

The American Petroleum Institute classifies motor oils into different grades according to their oil quality grades, and the standard is written in letters"s"It represents gasoline motor oil, and then the different grades of engine oil are listed in alphabetical order"s"After that, such as: se, sf, sg, sh, sj. And in the letters"s"The letters after that, in alphabetical order, indicate the higher the oil grade, e.g

The SH level is better than the SG level, and the SJ level is better than the SH level.

The Society of Automotive Engineers classifies the quality of engine oil according to the oil viscosity grade classification, the first type is single-grade viscosity type, and it is divided into high-temperature environment type and low-temperature environment type. The number marked after SAE indicates the viscosity of the oil at 100 degrees Celsius, and the larger the number, the greater the viscosity of the oil.

Because the viscosity of this oil is relatively large, it is more suitable for use in high temperatures in summer, and the higher the temperature, you should choose products with larger numbers. The grades of engine oil for low temperature environment are: SAE0W, SAE15W, SAE20W, the W after SAE indicates winter, and the number also indicates viscosity, the smaller the number means the smaller the viscosity.

Since this type of oil is used for low temperatures in winter and has a low viscosity, the lower the temperature, the lower the number of the oil. The lower the viscosity of the oil, the greater the starting speed of the engine; At the same time, the lower the pour point of the oil, the easier it is for the oil to be pumped, which can reach the lubrication part more quickly, and shorten the time for the engine to withstand dry friction. The second type is the all-weather type of multi-level viscosity

The oil grades are: SAE5W 30, SAE15W 40, SAE20W 50. The first half of the bars indicates the winter low-temperature viscosity properties that the marking oil complies with, and the second half of the bars indicates the summer high-temperature viscosity properties.

The lower the number before w, the better the fluidity of the lubricant at low temperatures and the easier it is to start the car. The larger the number after W, the better the viscosity of the oil in the high temperature environment, the stronger the oil film is generated, and this oil can basically be used for all seasons.

Usually, the grade of automobile engine oil is divided into ordinary engine oil, synthetic engine oil, semi-synthetic engine oil, and fully synthetic engine oil.