JPH01126398A - Lubricating oil composition for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide the titled composition stably functioning without deteriorating even in an atmosphere of NOX gas, by comprising as main components a base oil, having a specific viscosity and containing a slight amount of sulfur and a small amount of aromatic compounds and a benzylamine compound. CONSTITUTION:The objective composition comprises as main components (A) a basic oil (e.g. distilled oil, debitumenized oil or dewaxed oil) having a viscosity of 2-50cSt (preferably 3-20cSt) at 100 deg.C, a viscosity index of >=80 (particularly preferably >=100), a sulfur content of <=30ppm (particularly preferably <=10ppm) and an aromatic compound content of <=3% (preferably <=1%) and (B) a benzylamine compound of formula I-III (R<1>, R<5>, R<7> and R<9> are alkyl or alkenyl having a mol. wt. of 300-3,000; R<2>, R<6> and R<8> are 2-4C alkylene; R<3> and R<4> are H or 1-4C alkyl; m and n are 1-6), etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a lubricating oil composition for internal combustion engines, and more specifically to a lubricating oil composition for internal combustion engines that does not deteriorate and functions stably even in a nitrogen oxide (NO) gas atmosphere. Relating to oil compositions.

[Prior Art and Problems to be Solved by the Invention] In general, combustion gas in an internal combustion engine leaks into the crankcase as blow-by gas from between the piston and the cylinder. This combustion gas contains NO and gas at a fairly high concentration, which poses a problem in that it deteriorates the crankcase oil (internal combustion engine oil).

Incidentally, recently, an increasing number of automobiles are equipped with reduction catalysts such as three-way catalysts in order to comply with exhaust gas regulations, and it has become permissible to operate internal combustion engines more harshly (high speed, high output).

Furthermore, with the aim of improving fuel efficiency from the perspective of energy conservation, the weight of automobile bodies is being promoted, and crankcases are also becoming smaller, and the amount of crankcase oil (internal combustion engine oil) is also decreasing accordingly. . As a result, the concentration of NO and gas per unit amount of oil in the combustion gas leaking into the crankcase tends to increase significantly.

On the other hand, the above-mentioned N08 gas has a strong ability to degrade crankcase oil (internal combustion engine oil), and the higher the concentration of No3 gas per unit amount of oil, the greater its influence. Abnormal deterioration occurs frequently with oil,
It is becoming almost impossible to deal with this problem.

[Means for solving problems]

Therefore, the inventors of the present invention have conducted intensive research in order to solve the problems of conventional internal combustion engine oils as described above and to develop an internal combustion engine oil that is stable against NOx gas. In the research process,
It was discovered that benzylamine compounds have a significant effect on stability against NOx gas, and further research revealed that a composition that combines a specific highly purified base oil and benzylamine compounds could be used for the intended purpose. We found that it is possible to achieve this. The present invention was completed based on this knowledge.

That is, the present invention has (A) a kinematic viscosity of 2 at 100°C.
~50 cSt, viscosity index 80 or more, sulfur content 30
The present invention provides a lubricating oil composition for an internal combustion engine, the main components of which are a base oil having an aromatic content of 3% or less and (B) a benzylamine compound.

The base oil which is component (A) of the composition of the present invention is first
Kinematic viscosity at 00°C is 2 to 5 QcSt, preferably 3
~20 cSt. Here, if the kinematic viscosity is less than 2 cSt, there is a disadvantage that the evaporation loss is large;
If it exceeds 0 cSt, the power loss due to viscous resistance will be too large, so it is not preferable.

This base oil also has a viscosity index of 80 or more, preferably 90.
or more, more preferably 100 or more. Oils with a viscosity index of less than 80 are unsuitable as internal combustion engine oils because their viscosity changes significantly due to temperature changes. Note that when the viscosity index is 120 or more, the stability against noxious gases is further improved.

Further, the base oil has a sulfur content of 30 ppm or less, particularly preferably 10 ppm or less.

Here, if the sulfur content exceeds 30 ppm, the stability against NO and gas is insufficient, and the lubricating oil deteriorates significantly.

The base oils of the present invention also have an aromatic content of 3% or less (i.e., %
CA should be 3 or less), preferably 1% or less. If the aromatic content (%CA) exceeds 3%, deterioration in NO or gas atmosphere becomes significant, making it impossible to achieve the object of the present invention. Note that this aromatic content (%Ca) is a ring analysis value based on the ndM method.

As the base oil as component (A) of the composition of the present invention, various mineral oils can be used as long as they have the above-mentioned properties, and there are no particular limitations. Specific examples of mineral oils that can be used as base oils include distillate oils, deasphalted oils, and crude waxes obtained by distilling various crude oils (paraffinic base oils and intermediate base crude oils) at atmospheric pressure or under reduced pressure. It is obtained by hydrotreating (hydrocracking under particularly severe conditions), followed by distillation if necessary, and further dewaxing (solvent dewaxing and/or hydrogen dewaxing).

Furthermore, in the lubricating oil composition of the present invention, a base oil having the above-mentioned properties is used as the component (A), but if desired, other base oils may be used as long as the overall properties are maintained within the above-mentioned range. An appropriate amount can also be added to adjust the viscosity. Other base oils that can be used here include various mineral oils and are not particularly limited.

On the other hand, as the benzylamine compound as component (B) of the composition of the present invention, those represented by formulas (I) to (I[I) can be used.

IJ [In the formula, R', R', R), R'' has a molecular weight of 300 to 30
00 alkyl group or alkenyl group, R'', R6
, R- represents an alkylene group having 2 to 4 carbon atoms;
4 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, m,
n represents 1 to 6] Furthermore, the amount of the benzylamine compound in the composition of the present invention varies depending on the type of base oil 9 and the required characteristics for the composition, etc., and cannot be unambiguously determined. The amount is usually 1 to 10 parts by weight, preferably 2 to 6 parts by weight, per 100 parts by weight of the base oil (A).

The lubricating oil composition of the present invention is mainly composed of the above-mentioned base oil as the component (A) and the benzylamine compound as the component (B). It is also possible to add various additives that are included in lubricating oils. Here, a typical example of the additive used is zinc dialkyl or diaryldithiophosphate (ZnDTP), which is added to (A) 0.5 to 2 parts by weight per 100 parts by weight of the base oil; It is preferably blended in a proportion of 0.8 to 2 parts by weight. Furthermore, sulfonate finates and salicylate phosphonates of various metals (Ca, Mg, Ba, etc.).

Metal-based detergent such as naphthinate, (A) base oil 100%
It is also effective to add 1 to 20 parts by weight, and in addition, various antioxidants, viscosity index improvers, pour point depressants, extreme pressure agents, rust preventives, anti-wear agents, etc. agent,
Examples include friction modifiers, and in the present invention, these may be added as appropriate depending on the situation.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Examples 1 to 3 and Comparative Examples 1 to 8 A benzylamine compound (
In formula (n), R% is a polybutenyl group with a molecular weight of 1000 H
b is an ethylene group, m=3) and various additives,
A composition was prepared by blending the ingredients in the proportions shown in Table 2 with respect to 100 parts by weight of oil, and the NO8 deterioration test of the composition was conducted in the following manner. The results are shown in Table 2.

In addition, in the NOx deterioration test, the time until the acid value of the sample oil (composition) increases rapidly is referred to as the NOx deterioration life. In other words, in this NOx deterioration test, nitrogen monoxide (NO) gas with a concentration of 0.8% was added to the sample oil 40 in the presence of iron and copper catalysts (oxidation test JISK-2514 test pieces).
hr and humidified air at a rate of 10ffi/hr, the temperature of the sample oil was maintained at 140°C, and abnormal deterioration (
This was done by measuring the time at which the acid value (sudden increase) begins.

Table 1 (Properties of base oil) (Hereinafter in the margin) [Effects of the invention] As described above, the lubricating oil composition of the present invention is stable against NOx gas, and is therefore suitable for use in internal combustion engines with high NOx gas concentrations. Effectively used as a lubricant.

Patent applicant: Nissan Motor Co., Ltd.

Claims (1)

[Claims] (1) (A) Kinematic viscosity at 100°C is 2 to 50 cSt
A lubricating oil composition for an internal combustion engine, the main components of which are a base oil having a viscosity index of 80 or more, a sulfur content of 30 ppm or less, and an aromatic content of 3% or less, and (B) a benzylamine compound.