Lubricating oil compositions

Abstract

A lubricating oil composition which comprises a base oil, (A) a specific alkali metal salicylate derivative, a specific alkaline earth metal salicylate derivative and / or their (per)basic salt in an amount of 0.005 to 5 mass % in terms of the amount of the metal element (B) a phosphorus-containing wear inhibitor in an amount of 0.005 to 0.2 mass % in terms of the amount of phosphorus and (C) 0.01 to 1 mass % of an amide compound, and has a total sulfur content of 0.3 mass % or less, all the percentages being relative to the total amount of the composition. The lubricating oil composition is a low sulfur lubricating oil which is extremely excellent in wear inhibiting property and also excellent in long drain property and the like, and thus can be suitably used in particular for an internal combustion engine.

Description

technical field [0001] The present invention relates to a low-sulfur lubricating oil composition, more particularly to a lubricating oil composition suitable for internal combustion engines with excellent anti-wear properties and long-drain performance. Background technique [0002] Sulfur- and phosphorus-containing additives having excellent antiwear and oxidation properties, such as zinc dialkyldithiophosphates, have been used as essentially essential additives in general-purpose lubricating oils, especially those for internal combustion engines. However, lubricating oils containing less sulfur, phosphorus, and ash have been strongly requested now because it is necessary to reduce the impact on exhaust gas purification catalysts such as three-way catalysts, oxidation catalysts, and NOx adsorbents, or on internal combustion engines in accordance with recent environmental concerns. Harmful effects of exhaust gas aftertreatment devices such as Diesel particulate filters (DPF)...

AI Technical Summary

Problems solved by technology

However, it has been found that when reducing the levels of sulfur and phosphorus antiwear agents such as zinc dithiophosphate or using phosphorus-containing antiwear agents free of sulfur in order to reduce the sulfur content, the resulting compositions will not show a significant impact on internal combustion engine valves. Sufficient anti-wear properties of the system, such as anti-wear properties for rocker paddles and anti-wear properties for cams

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