Tonen Corporation

Tonengeneral Sekiyu K.k.

Katsuya Koganei

Toshiaki Kuribayashi

Hiroyuki Iwasaki

Satoshi Ogano

Hiroshi Nakanishi

Noboru Umemoto

Takeshi Nomura

The present invention provides for a lubricant oil composition for internal combustion engines for automobiles with enhanced friction loss reduction and is especially suitable for a pressure-accumulating (common rail) type diesel engine equipped with an EGR system. The lubricant oil composition contains a base oil composed of a mineral and/or synthetic oil incorporated with at least four additives of (A) at least one type of organomolybdenum compound selected from the group consisting of sulfurized oxymolybdenum dithiocarbamate, sulfurized oxymolybdenum dithiophosphate, molybdenum phosphate and molybdenum-amine complex at 0.01 to 0.20 wt. % as Mo, (B) zinc dialkyl dithiophosphate at 0.01 to 0.50 wt. % as P, (C) one of Ca and Mg salts of alkyl salicylate at 0.05 to 1.0 wt. % as Ca or Mg and (D) Zn salt of alkyl salicylate at 0.005 to 0.2 wt. % as Zn, all percentages being based on the whole composition, especially suitable for a pressure-accumulating (common rail) type diesel engine equipped with an exhaust gas recirculation (EGR) system.

Lubricant oil composition for internal combustion engines

This invention provides a lubricant oil composition for internal combustion engines which shows a sufficiently low volatility at high temperature and good low-temperature viscosity characteristics. The lubricant oil composition for internal combustion engines comprises a base oil which simultaneously satisfies the following relationships (a.sub.1) and (b.sub.1):

The present invention is directed to a zinc-molybdenum-based dithiocarbamate derivative which is a complex salt having the metallic components of zinc and molybdenum in the same molecule. When used as a lubricant additive, it imparts a notable friction-reducing effect to the lubricant composition in which it is incorporated, reducing its friction coefficient and improving its stability of friction coefficient at both low and high temperature, particularly at high temperature. In particular, it improves friction-related characteristics much more notably than a combination of a molybdenum and zinc compound.

Zinc-molybdenum-based dithiocarbamate derivative, method of producing

A lubricating oil composition for two-cycle engines, consisting essentially of, by weight: (1) 30% to 70% of a polyol ester having a kinematic viscosity of 9 to 15 cSt at 100.degree. C., 30% to 70% of a diester having a kinematic viscosity of 2 to 5 cSt at 100.degree. C., 1% to 5% of a polybutene having a molecular weight of 500 to 2,500 and/or 1% to 5% of a polymethacrylate having a molecular weight of 5,000 to 40,000, and 5% to 25% of a dispersant; or (2) 30% to 70% of a polyol ester having a kinematic viscosity of 4 to 15 cSt at 100.degree. C., 0% to 35% of a complex ester having a kinematic viscosity of 10 to 14 cSt at 100.degree. C., 10% to 70% of a diester having a kinematic viscosity of 2 to 5 cSt at 100.degree. C., and. 5% to 25% of a dispersant; or (3) a lubricating oil base, 5% to 25% of a polyamide dispersant, and 0.1% to 5% of a combination of a neutral calcium sulfonate and a neutral calcium salicylate, based on the total weight of the composition. Composition (1) is excellent in biodegradability, miscibility with gasoline, anti-seizure performance and detergency. Composition (2) is excellent in biodegradability. Composition (3) has excellent high-temperature detergency and low viscosity at low temperature and can be also made excellent in biodegradability, miscibility with gasoline and anti-seizure performance when the oil base in composition (1) is used as a lubricating oil base.

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Ohimachi, Japan

Katsuya Koganei