A few indicators you don't know in passenger car engine oils

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A few indicators you don't know in passenger car engine oils

China passenger car engine oil product standards, stipulates the quality specifications and viscosity specifications of gasoline engine oil, and sets the various performance indicators of the oil. The main oil specifications and viscosity, followed by four aspects of the oil's alkali value acid value, fuel dilution, elemental content. Viscosity specifications or follow the American Petroleum Institute API standards, not here in detail, today mainly take a look at the viscosity specifications in addition to the other three standards.

First, the alkali value of acid value

Total alkali value is a characterization of the content of alkaline components in gasoline engine oil, on behalf of the oil and the ability to neutralize acidic substances. Internal combustion engine in operation, the fuel (diesel, gasoline and biomass fuels) in the incomplete combustion process will produce acidic substances, strong polarity will be in the form of sludge, varnish and carbon deposits accumulated and adhered to the engine components. Alkaline substances in engine oil will neutralize these acids and prevent their accumulation and adhesion.

Generally speaking, the higher the quality level of the engine oil, the higher the alkaline content, the greater the total alkaline value, the stronger the cleaning ability; in the process of use, the alkaline value will gradually decline, if the decline is more than 50% of the alkaline value of the new oil, or lower than the corresponding acid value, it would be best to carry out the replacement.

Fuel Dilution

Engine in operation, fuel in the case of incomplete combustion back into the engine oil sump, after high-speed mixing, and engine oil mixing coexistence. Once the fuel dilution occurs, and more than a certain content, it will cause the viscosity of the oil to drop, which in turn affects the anti-wear properties, anti-oxidation properties and cleaning properties, excessive fuel dilution will cause a drop in the flash point of the oil, bringing potential safety hazards. Generally, if serious fuel dilution occurs, the oil sample will have obvious gasoline odor, if the monitoring flash point is reduced to below 150 ° C, or fuel dilution of more than 5.0%, the lubricating oil should be replaced, and check the engine components or carry out in-depth maintenance.

Elemental content

Engine oil contains detergents, dispersants, anti-wear agents and antioxidants and other functional additive components. Generally speaking, a wider range of additives elements for sulfur, phosphorus, calcium, zinc these four, elemental content in the oil stereotypes, will not change with the changes in the operating cycle, basically constant, can be detected through the new oil and in the use of oil in the content of these four elements to determine whether the oil is consistent.

Engine in the operation process, there is a certain degree of wear and tear of components. General engine parts design materials, the usual wear elements for copper, iron, aluminum, lead, through the determination of these four elements in the oil, on the one hand, you can assess whether the engine is running normally, on the other hand, you can assess whether the anti-wear performance of the oil is qualified, the general copper, aluminum and lead more than 30 μg / g, more than 70 μg / g of iron should be a cause for concern, and should be conditioned to replace the lubricant.