Toyota Jidosha Kabushiki Kaisha

Idemitsu Kosan Company, Limited

Nippon Oil Corporation

Tonengeneral Sekiyu Kabushiki Kaisha

Kazuo Yamamori

Masato Takahashi

Shigeki Matsui

Akihiko Ichikawa

Narihiko Yoshimura

Kenji Sunahara

Osamu Kurosawa

Toyoharu Kaneko

Tomohiro Kato

Yoshikazu Yamamoto

Hiroyuki Arai

Kosuke Fujimoto

Koji Saito

Toru Matsuoka

Tetsuzo Yoneda

Tetuzo Yoneda

Koji c/o Tonengeneral Sekiyu KK Saito

Tooru Matsuoka

Provided are a lubricating oil composition used in a diesel engine equipped with a forced-induction compressor, containing a base oil (A) containing a poly-&#x3b1;-olefin (A1), and a viscosity index improver (B) having an SSI (shear stability index) of 20 or less, having a distillation amount of a light fraction of 496&#xb0; C. or less in a gas chromatography distillation test of less than 80% by volume, having a high retention of the effect of suppressing the formation of deposits that may occur inside the compressor, and being capable of retaining a high efficiency of the compressor for a long period of time, in the use thereof in a diesel engine equipped with a forced-induction compressor having an outlet temperature of the compressor becoming a high temperature reaching 190&#xb0; C. or more, and a method for using the lubricating oil composition.

Lubricating oil composition and use method therefor

The present invention relates to a lubricating oil composition containing a base oil (A), a molybdenum dithiocarbamate (B), an ester-based ashless friction modifier (C), and a metal salicylate (D), wherein the content of a molybdenum atom derived from the molybdenum dithiocarbamate (B) is 650 ppm by mass or more on the basis of the whole amount of the lubricating oil composition; a content ratio [C/B] of the ester-based ashless friction modifier (C) to a molybdenum atom derived from the molybdenum dithiocarbamate (B) is 5.0 to 10 in terms of a mass ratio; the content of a salicylate soap group derived from the metal salicylate (D) is 0.50% by mass or more on the basis of the whole amount of the lubricating oil composition; and a kinematic viscosity at 100&#xb0; C. is 4.0 mm/s or more and less than 9.3 mm/s, and a high-temperature high-shear viscosity at 150&#xb0; C. is 1.7 mPa&#xb7;s or more and less than 2.9 mPa&#xb7;s. In accordance with the present invention, a viscosity-reduced lubricating oil composition in which nonetheless a molybdenum dithiocarbamate and an ashless friction modifier are jointly used, not only friction can be reduced early after commencement of lubrication, but also such a state can be maintained, is provided.

Lubricating oil composition

Provided is a lubricating oil composition for manual transmissions which has anti-seizure properties for shift forks and can provide manual transmissions with excellent shifting characteristics though it has a low viscosity and can save fuel to be used in automobiles. The lubricating oil composition for manual transmissions comprises a lubricating base oil with a kinematic viscosity at 100&#xb0; C. of 4 to 6 mm/s, on the basis of the total mass of the composition, (A) 0.14 to 0.20 percent by mass in terms of magnesium of magnesium sulfonate, (B) 0.14 to 0.18 percent by mass in terms of zinc of a specific zinc dithiophosphate, (C) 0.3 to 0.5 percent by mass in terms of sulfur of a sulfur-containing extreme pressure additive other than zinc dithiophosphate, and (D) 0.02 to 0.05 percent by mass in terms of phosphorus of an alkyl phosphite, and having a kinematic viscosity at 40&#xb0; C. of 25 to 30 mm/s.

Lubricating oil composition for manual transmission

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Nagoya, Japan

Kazuo Yamamori