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--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 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 C. or more, and a method for using the lubricating oil composition.

The present invention relates to a lubricating oil composition containing: (A) a poly--olefin base oil obtained by using a metallocene catalyst; (B) a mineral oil-based base oil exhibiting a distillation curve with a temperature gradient |Dt| of distillation temperature between two points 2.0 vol % and 5.0 vol % of distillation amount being 6.8 C./vol % or less; and (C) an ester-based base oil in an amount of 6% by mass or more based on a total amount of the composition.

Provided is a lubricating oil composition containing a mineral base oil (A) having a temperature gradient |Dt| of a distillation temperature between two points of a distillation amount of 2.0% by volume and a distillation amount of 5.0% by volume in a distillation curve of 6.8 C./% by volume or less, and an antioxidant (B) containing an amine-based antioxidant (B1), a phenol-based antioxidant (B2), and a phosphorus-based antioxidant (B3), wherein the content of the component (B3) is 0.06 to 1.0% by mass based on the total amount of the lubricating oil composition. The lubricating oil composition is a long-life lubricating oil composition that maintains excellent oxidation stability even for long-term use in a high-temperature environment, and has a high effect of suppressing the generation of sludge for a long period of time.

A refrigerating machine oil having a kinematic viscosity at 100 C. of 0.5 mm.sup.2/s or more and 2.5 mm.sup.2/s or less, a distillation end point in gas chromatography distillation of 380 C. or more and 450 C. or less, and a sulfur content of 0.001 mass % or more and 0.2 mass % or less.

A method for producing hydrocarbon solvents having a sulfur content of less than 10 ppm, aromatic hydrocarbon content of less than 500 ppm, an initial boiling point higher than or equal to 300 C. and final boiling point lower than or equal to 500 C., for a fraction interval of a maximum of 100 C., and pour point lower than 25 C. according to the standard ASTM D5950, comprising of the following steps of: dewaxing of a hydrocarbon fraction having initial boiling point higher than 300 C. derived from the distillation of a gas oil fraction, hydrodearomatisation of all or part of the dewaxed effluent, in the presence of a catalyst comprising nickel on an alumina base, at a pressure ranging from 60 to 200 bar and a temperature ranging from 80 C. to 250 C., recovery of the dewaxed and dearomatised fraction, distillation in fractions of the dewaxed and dearomatised fraction, recovery of at least one 300 C.+ fraction having pour point lower than 25 C., this fraction having a distillation interval lower than 100 C.

Base stocks having Group III/III+ characteristics are prepared from certain advantageous crude oils via simplified process configurations and/or under less severe process conditions. Crude oils comprising a vacuum gas oil (VGO) fraction having a ratio of a sum of paraffin content plus 1-Ring species content to multi-ring species content that is greater than or equal to about 1.5 are advantageous in this context. Other parameters such as API gravity and crude compositional ranges may also be considered for identifying advantageous crudes. In some instances, advantageous crudes are processed into Group III base stocks via a process configuration in which the crude oil is directly supplied to a hydroprocessing unit.

A refrigerating oil comprising a lubricating base oil, a first extreme pressure agent containing sulfur and phosphorus as constituent elements and a second extreme pressure agent containing phosphorus but not containing sulfur as constituent elements, and having a kinematic viscosity at 100 C. of 0.5 mm.sup.2/s or more and 2.5 mm.sup.2/s or less.

The disclosure relates to an electrocrushing drilling fluid with an electrocrushing drilling base fluid including a non-polar oil, water, and glycerin. The base fluid may further include a polar oil and an alkylene carbonate. The electrocrushing drilling fluid may further contain at least one additive. The electrocrushing drilling fluid may have a dielectric constant or dielectric strength of at least a set amount, an electric conductivity less than a set amount, or a combination of these properties. The disclosure further relates to an electrocrushing drilling system containing the electrocrushing drilling fluid and an electrocrushing drill bit.

Disclosed is a mineral base oil including 85 to 92 wt % of a paraffinic hydrocarbon and 8 to 15 wt % of a naphthenic hydrocarbon and having a Noack volatility of 10 to 12 wt % and a viscosity index of 132 to 142.

A hydrocarbon fluid is disclosed that has a pour point of at most 30 C., as measured by ASTM D5950, and that comprises at least 99 wt % of naphthenes and paraffins, based on the total weight of the hydrocarbon fluid, wherein the weight ratio of naphthenes to paraffins is at least 1, as measured by GC-MS, and wherein the paraffins consist essentially of isoparaffins, as determined by GC-FID. In addition, preferred uses of said hydrocarbon fluid are disclosed.