Nippon Oil Corporation

Nippon Mitsubishi Oil Corporation

Japan Petroleum Energy Center

Isao Kurihara

Kazuhiro Yagishita

Kiyoshi Inoue

Jinichi Igarashi

Mineo Kagaya

Shouzaburou Konishi

The invention provides lubricant compositions for diesel engines having a regenerative DPF, which prolong life of the DPF by inhibiting accumulation of components depositable on DPF inner walls, diesel engine systems having a regenerative DPF with prolonged life, and a method for inhibiting accumulation of components depositing on the DPF in the system. The present composition is for diesel engines having a regenerative DPF and running on diesel fuel with &#x3c;10 mass ppm sulfur, contains a base oil and additives including (A) metal detergent, (B) ashless dispersant, and (C) phosphorus-based anti-wear agent, and satisfies the conditions of a sulfated ash content of 0.4-2 mass %, an atomic ratio of metal from component (A) to the total phosphorus of 0.2-3, an atomic ratio of the total boron to metal from component (A) of 0.2-2, and an atomic ratio of the total sulfur to metal from component (A) of 0-4.

Lubricating oil composition for diesel engine

Low sulfur lubricating oil compositions are provided which are extremely excellent in anti-wear properties for the valve train system of an internal combustion engine and are also excellent in long-drain properties, and thus is suitable for used in an internal combustion engine. The lubricating oil compositions comprises a lubricating base oil, (A) a specific alkali metal or alkaline earth metal salicylate and/or an overbased or basic salt of the salicylate, (B) a phosphorus-containing anti-wear agent, (C) an ashless dispersant, and (D) an ashless anti-oxidant, as the essential components, and contains boron in an amount of 0.01 to 0.15 percent by mass and sulfur in a total amount of 0.3 percent by mass or less, based on the total mass of the composition.

Lubricating oil composition

Engine oil compositions are provided containing (A) a lubricating base oil having a kinematic viscosity at 100&deg; C. of 3 to 6 mm /S, a viscosity index of 120 or more, and a total aromatic content of 5 percent by mass or less and (B) a polymethacrylate-based viscosity index improver, preferably having a weight average molecular weight of 180,000 or more, (A) and (B) being blended in such an amount that the composition has a kinematic viscosity at 100&deg; C. of 4.0 to 9.3 mm /s. The engine oil compositions may also contain a molybdenumdithiocarbamate, as well as one or more other engine oil additives. The engine oil compositions preferably have a high-temperature, high shear viscosity at 150&deg; C. of 2.4 to 2.7 mPa&middot;s, a NOACK evaporation loss of 16 percent by mass or less, and a CCS viscosity at &minus;25&deg; C. of 3500 mPa&middot;s or less.

Engine oil compositions

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Yokohama, Japan

Isao Kurihara