JPH0329839B2 - - Google Patents

Abstract

PURPOSE:To provide the titled lubricating oil compsn. which does not require renewal for a long period and has an extended service life, prepared by adding calcium phenate, manganese sulfonate and alkylsuccinimide to a base lubricating oil. CONSTITUTION:The lubricating oil compsn. is prepd. by adding 1-7wt% calcium phenate with a basicity value of 60-300, 0.1-5wt% magnesium sulfonate with a basicity value of 100-450 and 1-5wt% alkylsuccinimide (e.g. polybutenylsuccinimide of tetraethylpentamine) to a base lubricating oil comprising of a mineral oil and/or synthetic oil having a kinematic viscosity of 3-30cSt at 100 deg.C. EFFECT:Impurities can be filtered out readily and wear of lubrication or valve system is reduced to a marked extent, for fine solid impurities formed in a combustion chamber are aggregated into large-sized particles.

Description

[Detailed description of the invention]

The present invention relates to a lubricating oil composition for diesel engines, and more specifically, it is capable of agglomerating solid impurities such as soot, which are inevitably generated during engine operation, into a particle size that can be removed by a filter or other filtration means. Furthermore, the present invention relates to a lubricating oil composition for a diesel engine that can agglomerate solid impurities, which significantly suppresses wear in a valve train system due to solid impurities, and therefore has a long oil change period and extended service life. Compared to gasoline engines, diesel engines have higher combustion pressure and higher temperatures in the combustion chamber, and due to their combustion mechanism, incomplete combustion is more likely to occur.As a result, diesel engines produce combustion residues or soot caused by oxidative decomposition of lubricating oil, which is insoluble in the oil. A large amount of solid impurities (about 0.2 μm in size) are generated, which inevitably leads to a situation where these contaminate the lubricating oil or lubricating system. If the amount of this mixture increases, first of all, the wear of the valve train such as the Rocker arm and cam becomes severe, and furthermore, the viscosity of the lubricating oil itself increases, resulting in an increase in power loss and a decrease in the cooling ability between the piston and liner. , a clogging phenomenon occurs in the lubrication system, which impedes smooth lubrication management of the diesel engine. In order to solve such problems, traditionally,
In order to prevent oxidative decomposition of lubricating oil, for example, zinc dithiophosphate and the solid impurities mentioned above are dispersed in the oil as fine particles, and in order to prevent them from agglomerating into deposits, so-called cleaning agents are used. Various compounds called dispersants are added to the lubricating oil itself to improve its cleanliness (Japan Lubrication Society, ``Lubrication Handbook'', ed.
(See expanded 6th edition, pp. 310-315, 1982). However, even in this case, there is a limit to the ability to eliminate the negative effects of solid impurities such as soot, and the current situation is that the lubricating oil is changed after a relatively short period of time (usually 5,000 to 10,000 km). In particular, in the case of diesel engines equipped with EGR (exhaust gas recirculation) devices, which have been introduced in recent years as an exhaust gas countermeasure, the amount of soot generated is even greater, so it is difficult to deal with it using the methods described above. It has become virtually impossible to manage lubrication. Therefore, there is a strong desire to develop a lubricating oil that can further improve cleanliness and further suppress wear in valve train systems. While conducting extensive research to achieve the above objective, the present inventors discovered a technical idea that is completely opposite to the conventional technical idea of dispersing solid impurities in oil. Based on this idea, he came up with the idea that if solid impurities were aggregated into coarse particles and captured and removed by a bypass filter installed in the circulation system, the lubricating oil could be circulated in a clean state at all times. When we searched for compounds that would be effective, we were surprised to find that even calcium phenate and magnesium sulfonate, which are already known as detergent and dispersants in commonly used base oils, have base numbers within a specific range. A lubricating oil made by blending a predetermined amount of
We discovered that the lubricating oil composition of the present invention can be aggregated to a size of 1 μm, and developed the lubricating oil composition of the present invention. That is, the solid impurity agglomerating diesel engine lubricating oil composition of the present invention contains 1 to 7% by weight of calcium phenate with a base number of 60 or more and magnesium with a base number of 100 or more in a base oil consisting of mineral oil and/or synthetic oil. The composition is characterized by the addition of 0.1 to 5% by weight of sulfonate and 1 to 5% by weight of alkenylsuccinimide. In the lubricating oil composition of the present invention, the base oil used is not particularly limited, and any mineral oil, synthetic oil, or a mixture of both in an appropriate ratio that is commonly used as a base oil for lubricating oils may be used. good. in this case,
From the viewpoint of maintaining and improving lubricity, reducing power loss, and preventing excessive oil consumption, it is preferable to adjust the kinematic viscosity of the base oil at 100° C. to a range of 3 to 30 centistokes (cSt). The lubricating oil composition of the present invention is constructed by adding calcium phenate, magnesium sulfonate, and alkenyl succinimide, which will be described later, to the base oil described above. First, the base number of the calcium phenate used in the present invention is set in a range of 60 or more.
The upper limit of the base number is not particularly limited, but those with a base value of 300 or less are easily available and convenient. Preferably
It is 100-250. In addition, the base number as used in the present invention is a measure of the amount of basic components, and is expressed in mg of potassium hydroxide equivalent to 1 g of basic components.
Its unit is mgKOH/g. If the base number is less than 60, the neutralizing effect on sulfuric acid in the combustion products will not be sufficiently exerted, and as a result, the function to prevent corrosion or wear of the valve train will be reduced, or solid impurities will be present. This can cause problems such as agglomeration and large amounts of deposits inside the engine. Such calcium phenotes are prepared by conventional known methods, such as by carbonating calcium salts of various alkylphenols or sulfurized alkylphenols. At this time, the overall base number is set within the above range by appropriately adjusting the type of raw materials used (for example, the type of alkyl group), the quantitative ratio, the degree of carbonation, etc. The amount of calcium phenate added is set at 1 to 7% by weight based on the total weight of the lubricating oil to be prepared.
Preferably it is 3 to 6% by weight. If the amount added is less than 1% by weight, no effect will be obtained, and if it exceeds 7% by weight, disadvantages such as accelerated wear of the valve train will occur. Next, the magnesium sulfonate used in the present invention is set to have a base value of 100 or more, and an addition amount of 0.1 to 5% by weight. The upper limit of the base number is not particularly limited, but those with a base value of 450 or less are easily available. Preferably 200-450, 0.5, respectively
~4% by weight. When the base number is less than 100, the aggregation effect is reduced and solid impurities are finely dispersed, resulting in an inconvenient situation in which the wear-inhibiting effect on the valve train is reduced. In addition, the amount added is less than 0.1% by weight or 5% by weight
If it exceeds this amount, the above-mentioned aggregation effect will not be exhibited. Such magnesium sulfonates can be prepared by carbonating magnesium salts of various aliphatic sulfonic acids or aromatic sulfonic acids, and in this case, the same steps as in the case of calcium phenate preparation are made. In this embodiment, it is necessary to adjust the base number to the above-mentioned range of 100 or more. Alkenyl succinimide, which is the third component of the additive according to the present invention, is added mainly to prevent low-temperature sludge during engine operation and to adjust the cohesive force of solid impurities together with the calcium phenate and magnesium sulfonate. . The amount added is set at 1 to 5% by weight based on the total weight of the lubricating oil composition. Preferably it is 2 to 4% by weight. If the amount added is less than 1% by weight, the effect of the addition will not be exhibited, and if it exceeds 5% by weight, an inconvenient situation will occur in which the effect of aggregating solid impurities is hindered. Examples of alkenyl succinimide include:
A polyolefin having a molecular weight of 300 to 5,000 is reacted with maleic anhydride to form monoalkenyl succinic anhydride, which is then further reacted with a polyamine such as tetraethylenepentamine to be imidized. Also, special public service 1977-8013, special public service 1977-8013,
Boron compound derivatives of alkenylsuccinimides such as those described in JP-A No. 8014, JP-A No. 51-52381, JP-A No. 51-130408, and JP-A No. 54-87705 can also be used. In the present invention, polyptenyl succinimide of tetraethylpentamine is preferred. The lubricating oil composition of the present invention is basically composed of the above ingredients, but in order to further increase the effect, calcium sulfonate with a base number of 80 or less is added to 20% of the lubricating oil composition.
Adding less than 0.5% by weight, preferably 0.5 to 10% by weight, will further improve the soot in the lubricating oil and the wear condition of the valve train. In addition, commonly used oil-based agents (higher alcohols, etc.), extreme pressure agents (lead soap, etc.), viscosity index improvers (isobutylene polymers, etc.), antifoaming agents (silicone oil, etc.), and antioxidants (zinc dithiophosphate, etc.) It goes without saying that various additives such as the following may be further added here. By using the lubricating oil composition of the present invention, fine solid impurities generated in the combustion chamber can be agglomerated and coarsened, making it easy to remove the impurities through a filter, thereby preventing the impurities from entering the lubricating oil or lubricating system. Since contamination can be prevented, wear in the valve train system can be significantly suppressed, and deterioration of the lubricating oil itself is also suppressed, extending its service life and, therefore, requiring longer oil replacement periods, making it more economical. It is possible to obtain beneficial effects such as , etc., and its industrial value as a lubricating oil for various internal combustion engines, especially diesel engines, is extremely large. The present invention will be explained in more detail below based on examples. Examples Various lubricating oils having the compositions shown in Table 1 were prepared.

【table】

[Table] For each lubricating oil, the conditions shown in Table 2 were used using a Toyota L-type diesel engine (displacement 2200c.c.) equipped with a bypass filter with a mesh size of 0.8μm in the lubrication system and equipped with EGR. A cycle test was conducted to evaluate the performance.

[Table] After 48 cycles of operation, remove each lubricating oil and
The kinematic viscosity (cSt) at 100℃ is measured using the JISK2283 method, and solid impurities mixed in the lubricating oil are determined.
Weighed according to ASTM D893B method. In addition, the state of damage to the rocker pad after the test was expressed on a demerit rating scale of 0 to 100 (0: best, 100: worst) to evaluate the wear state of the valve train. The above results are collectively shown in Table 1. The test results of the reference examples in Table 1 are data obtained when no bypass filter was provided in the lubrication system. Test Example The following samples were used. (a) Composition of Example 1 (b) Example 6 (c) 88.2% mineral oil, 3.0% calcium sulfonate with base number 330, polybutenyl succinimide of tetraethylenepentamine (molecular weight of polybutenyl group 1000) 3.0 %, zinc dithiophosphate 0.8% and ethylene-propylene copolymer 5.0% (all % by weight) (d) 85.7% mineral oil, 2.5% calcium sulfonate with a base number of 25, 3.0% calcium sulfonate with a base number of 330, Composition of 3.0% polybutenylsuccinimide (polybutenyl group molecular weight 1000) of tetraethylenepentamine, 0.8% zinc dithiophosphate, and 5.0% ethylene-propylene copolymer (all weight %) (E) Composition of Comparative Example 3 99g of sample and standard soot (carbon black HAF,
(manufactured by Asahi Carbon Co., Ltd.) and heated and stirred at 80° C. for 8 hours. Drop this onto the cell, set it on a microscope with a heating mechanism, and increase the magnification while raising the temperature at 10℃/min.
Observed at 200x magnification. The presence or absence of cohesion was determined based on the state of soot dispersion at 100-150°C. Sketches of the microscopic field of view are shown in Figures 1 b to d.
After raising the temperature using each of Sample A and Sample B, which are compositions of Examples, both soots coagulated well. A schematic diagram of the soot at that time is shown in Figure 1d. The soot after heating using Sample C, which is a composition of a comparative example, was insufficiently agglomerated. A schematic diagram of the soot at that time is shown in Figure 1b. After raising the temperature using each of Sample 2 and Sample E, which are compositions of comparative examples, soot hardly aggregated in both samples. A schematic diagram of the soot at that time is shown in Figure 1C. In addition, FIG. 1a shows a schematic diagram of soot before heating using samples I to E. From FIGS. 1a to 1d, it can be seen that Samples A and B, which are the compositions of the present invention, clearly aggregate when the temperature is increased. In contrast, Samples C, D, and E, which are conventional compositions, have low agglomeration, indicating that they function as a dispersant. Evaluation Comparison between the composition of the present invention and a composition that does not contain magnesium sulfonate (Comparative Example 2 and Examples 1 to 12) The valve train wear score (disadvantage score) of Comparative Example 2 that does not contain magnesium sulfonate is 49. , the amount of solid impurities in the lubricating oil is 3.3% by weight.
On the other hand, in Examples 1 to 12, the wear score is 6.0 or less, and the amount of solid impurities is 1.4% by weight or less. In other words, calcium phenate alone does not exhibit a flocculating effect on solid impurities. Comparison between the composition of the present invention and a composition using calcium sulfonate in place of magnesium sulfonate (Comparative Examples 3 and 12 and Example 10) In Comparative Example 12, in which magnesium sulfonate was replaced with calcium sulfonate having a base number of 330,
The wear rating is 48 and the amount of solid impurities is 3.4% by weight. This is clear from the fact that the wear score of Example 10 using magnesium sulfonate was 1.0 and the amount of solid impurities was 1.0% by weight.
This replacement increased the amount of solid impurities in the lubricating oil, indicating that the wear of the valve train became significant. Comparative Example 3, in which magnesium sulfonate was replaced with calcium sulfonate with a base number of 25, also showed a similar tendency (wear rating: 40, amount of solid impurities).
2.2% by weight). In other words, even when calcium phenate and calcium sulfonate are combined, they do not exhibit a flocculating effect on solid impurities. Comparison between the composition of the present invention and a composition in which the base number of magnesium sulfonate is less than 100 (Comparative Examples 8 and 9 and Examples 1 to 12) The base number of magnesium sulfonate is 50 and 80
The wear ratings of Comparative Examples 8 and 9 were 32 and 45, and the solid impurity amounts were 2.3 and 3.2.
This value is significantly higher than any of Examples 1-12. In other words, even in the case of a combination of calcium phenate and magnesium sulfonate, if the base number of the magnesium sulfonate is less than 100, no flocculating effect is shown on solid impurities. Comparison between the composition of the present invention and a composition using magnesium phenate instead of calcium phenate (Comparative Example 7 and Example 10) In Comparative Example 7 using magnesium phenate, the wear rating was 32, The amount of solid impurities is 2.3% by weight. This is an example using calcium phenate
When compared with 10, the difference in effectiveness is remarkable. In other words, magnesium phenate and base number are
In combination with magnesium sulfonate of 100 or more, it shows no flocculating effect on solid impurities. Comparison between the composition of the present invention and a composition in which calcium phenate has a base number of less than 60 (Comparative Examples 5 and 6 and Examples 1 to 12) Comparative Examples 6 and 5 in which calcium phenate has a base number of 25 and 50 The wear scores of both examples are 36, and the amount of solid impurities is 2.8 and 2.0, which are higher values than any of Examples 1 to 12. In other words, the combination of calcium phenate with a base number of less than 60 and magnesium sulfonate with a base number of 100 or more does not exhibit a flocculating effect on solid impurities. Others Compositions containing less than 1% by weight of calcium phenate (Comparative Examples 10 and 11) and compositions containing no alkenylsuccinimide (Comparative Examples 4 and 5) also exhibit the same tendency as described above. As is clear from the above, the base number is 60
The solid impurity agglomerating diesel engine lubricating oil composition of the present invention is a combination of the above calcium phenate, magnesium sulfonate having a base number of 100 or more, and alkenyl succinimide in specific amounts. By aggregating it well, it can be filtered, and wear of the valve train in diesel engines is greatly suppressed.

[Brief explanation of drawings]

FIGS. 1A to 1D are schematic views (sketches) of a sample obtained by mixing a diesel engine lubricating oil composition and standard soot and heating the mixture and observing it under a microscope. Figure 1a shows the control, and corresponds to the state of each sample in the test example before heating up, Figure 1b corresponds to sample C, Figure 1c corresponds to samples D and H, and Figure 1d corresponds to samples A and B. are doing.

Claims (1)

[Claims] 1. 1 to 7% by weight of calcium phenate having a base value of 60 or more in a base oil consisting of mineral oil or/and synthetic oil;
Magnesium sulfonate with base number 100 or more 0.1~
1. A lubricating oil composition for a diesel engine capable of aggregating solid impurities, characterized in that the composition contains 5% by weight of an alkenylsuccinimide and 1 to 5% by weight of an alkenylsuccinimide. 2. The solid impurity agglomerating diesel engine lubricating oil composition according to claim 1, wherein the base oil has a kinematic viscosity of 3 to 30 centistokes at 100°C.