API Special | API Oil Standard Interpretation


API oil is mainly divided into three categories: starting with "S" to represent gasoline engine oil; Start with "C" for diesel oil; When "S" and "C" exist at the same time, it means that the oil is a general purpose both for diesel and gasoline engines.


API is the oil quality standard issued by the American Petroleum Institute, and is also one of the most widely used oil standards in the world. API oil is mainly divided into three categories: starting with "S" to represent gasoline engine oil; Start with "C" for diesel oil; When "S" and "C" exist at the same time, it means that the oil is a general purpose for diesel and gasoline engines.

API level details

About turbine oil grade classification:

Our country is classified according to API standards - SA < SB... < SP, (Begins with an S, followed by the letters A, B, C... The later the order, the higher the quality grade, the better the performance) At present, SP is the highest grade of gasoline engine oil.


About diesel oil grade classification:

Our country is classified according to API standards - CA < CB... < CK, (Begins with C, followed by the letters A, B, C... The further back the order, the higher the oil grade, the higher the various technical indicators, and the better the performance) CK-4 is currently the highest level of diesel oil. And -4 means suitable for four-stroke engines.

API SP与API CK-4


1, API engine oil

API SN Plus and API SP are new standards developed to solve the problem of low-speed early ignition, and the requirement of low ash effectively reduces the occurrence of low-speed early ignition of turbocharged gasoline direct injection engines.

Compared with the API SN Plus standard, API SP upgrades key performance such as energy saving, oil sludge protection, piston cleanliness, oxidation control, and so on, aiming to give the engine better performance protection. At the same time, the wear test of the timing chain is increased, and higher requirements are put forward for the certified oil.

2, API diesel oil

The 2016 CK-4 standard is based on the 2006 CJ-4 standard

1, improve oxidation stability.

2, improve the inflation capacity.

3, improve wear protection.

4, improve the shear stability.

5. Improved fuel economy.

6, the minimum HTHS viscosity of the oil is 3.5cP. (Better oil film strength)

7, the oil is compatible with existing and new diesel engines.

8, CK-4 provides lower viscosity oil. (5W, 10W)





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