CN102477340B - Lubricant composition for internal combustion engines - Google Patents

Abstract

A lubricating oil composition for an internal combustion engine, comprising a lubricating oil base oil and a sulfonate detergent, wherein the content of the sulfonate detergent is 0.8 to 1.5% by mass based on the composition, and the sulfonate detergent includes Ultra-high base value calcium sulfonate with a base value of more than 400mgKOH/g, high base value calcium sulfonate with a base value of 300-350mgKOH/g and lithium sulfonate with a base value of less than 150mgKOH/g. The lubricating oil composition has low sulfur, phosphorus and sulfate ash content, and the additives used are relatively low in cost, easy to obtain, and have good economical efficiency. While satisfying the normal operation of the engine, it can also meet the exhaust gas recirculation requirements of the vehicle. (EGR) system works normally.

Description

A kind of internal combustion engine lubricating oil composition

technical field

The present invention is an internal combustion engine lubricating oil composition, specifically, a lubricating oil composition for gasoline and diesel engines.

Background technique

With the increase of the number of automobiles in our country, automobile exhaust emission has become the main factor of polluting the environment. The exhaust gas contains substances that seriously pollute the air such as carbon monoxide, hydrocarbons and nitrogen oxides. Therefore, it is very necessary to filter and absorb vehicle exhaust. The current method of treating automobile exhaust is to install an exhaust converter, and the three-way catalyst in the converter oxidizes carbon monoxide and hydrocarbons in the exhaust to carbon dioxide and water, and nitrogen oxides are reduced to nitrogen and oxygen.

Three-way catalysts are very sensitive to sulfur, phosphorus and ash in engine lubricating oil. Excessive sulfur content will lead to an increase in acidic substances in the engine, and excessive sulfate ash will form particles that are adsorbed on the particulate filter and further aggregated to increase the back pressure of the particulate filter, resulting in exhaust gas recirculation in the engine and fuel Consumption intensifies. Excessive phosphorus content will poison and deactivate the three-way catalyst in the particulate filter. Therefore, reducing the sulfur, phosphorus and ash content in engine oil is one of the future development directions.

The currently developed low-sulfur, low-phosphorus and low-ash automobile engine lubricating oil compositions mainly contain sulfur-free additives such as alkyl salicylates. Because alkyl salicylates have excellent high-temperature detergency, they can be Meet various performance requirements with less dosage.

CN1493671A discloses a diesel engine oil lubricating oil composition for fuel with a sulfur content of less than 50 ppm, wherein at least one metal detergent is used, and the total amount of ash produced by the metal detergent is less than 1.0 wt%. The detergent contains at least one alkyl salicylate. MackT-10 test shows that its lead corrosion results are good.

CN1746279A discloses a lubricating oil composition, wherein the sulfur content is less than 0.3wt%, the phosphorus content is less than 0.08wt%, the ash content is less than 0.8wt%, and the formula contains a salicylate fatty acid additive.

CN1746280A discloses a low-sulfur, low-phosphorus and low-ash lubricating oil composition, wherein the sulfur content is less than 0.3wt%, the phosphorus content is less than 0.08wt%, and the ash content is less than 0.8wt%. Boron-containing additives and total Alkyl salicylate with a base value of 200-400 mgKOH/g, wherein the mass ratio of nitrogen and boron in the ashless dispersant is 3-5:1. The composition has the functions of reducing the viscosity of lubricating oil and improving the cleaning performance of pistons.

The base value of the lubricating oil composition disclosed by CN1754950A is 8-9mgKOH/g, the sulfur content is less than 0.3wt%, the phosphorus content is less than 0.08wt%, the ash content is less than 0.8wt%, and contains a high-alkaline magnesium salt detergent and 2.5-4% nitrogen-containing dispersant.

CN1782047A discloses a kind of lubricating oil composition that sulfate ash content is less than 1%, comprises lubricating oil base oil, alkyl salicylate calcium detergent, the magnesium salt of at least 200ppm and the ashless dispersant of low molecular weight, and this composition can Reduced wear on engine piston top rings in MackT-10.

CN1782048A discloses a lubricating oil composition with a sulfated ash content of less than 1%, which includes a lubricating oil base oil, a calcium alkyl salicylate detergent, an overbased magnesium detergent of at least 200 ppm and an oil-soluble molybdenum of at least 20 ppm Sulfur-containing molybdenum compounds, at least 0.09% nitrogen nitrogen-containing dispersants for lubricating oils, the composition can reduce engine piston top ring wear in internal combustion engines.

USP6569818 discloses a lubricating oil composition, the composition contains 0.01-0.3% sulfur, 0.01-0.1% phosphorus, 0.1-1% sulfate ash, 0.2-7% metal salt, wherein the sulfur content of the base oil Less than 0.1%, 0.01-0.3% ashless dispersant (in terms of nitrogen atom content), the metal detergent is selected from non-sulfurized alkali metal or alkaline earth metal alkyl salicylate with a base value of 10-350mgKOH/g, Or non-sulfurized alkali metal or alkaline earth metal salts of alkylphenol derivatives with Mannich (Mannich) base structure, 0.01 to 0.1% of dialkylzinc disulfide, 0.01 to 5% of zinc disulfides selected from the group consisting of amines and Antioxidant of phenolic compounds.

The lubricating oil composition disclosed in USP7563752 mainly includes: 0.005-0.2% alkali metal or alkaline earth metal alkyl salicylate, 0.005-0.2% phosphorus-containing anti-wear agent, 0.01-1% amide compound, in the composition The total sulfur content is 0.3%.

The study found that the combination of alkyl salicylate, perbasic sulfonate and phenate in the formulation, and then compounded with other additives, can improve the high-temperature detergency of the lubricating oil composition while ensuring that other requirements are met .

CN101108995A discloses a lubricating oil composition with a phosphorus content of less than 0.12%, a sulfur content of less than 0.4%, and a sulfated ash content of less than 1.0%, with a total base number of about 7 to 15, including a major amount of base oil and a minor amount of overbased magnesium Detergent and at least 0.5% by weight of an ashless antioxidant selected from the group consisting of sulfur-free phenolic antioxidants, amine-containing antioxidants and mixtures thereof, the overbased magnesium detergent contributing more than 60 to the total base number of the lubricating oil %. The composition has good oxidation resistance and wear resistance.

CN1183237C discloses a heavy-duty diesel engine lubricating oil composition with a phosphorus content of less than 0.1%, which includes ashless dispersant, neutral calcium phenate, oil-soluble overbased calcium sulfonate and overbased magnesium sulfonate mixture, dioxane Based on zinc dithiophosphate and ashless antioxidant, the composition has good high-temperature detergency, anti-wear and anti-oxidation stability.

USP6730638 discloses a low-ash, low-phosphorus, low-sulfur internal combustion engine engine oil lubricating oil, composed of a base oil with a sulfur content of 300ppm as the main amount, 0.5-10% boron-containing ashless dispersant, and 0.05-1.5% molybdenum-containing friction improvement agent, 0.05-5.0% of at least one metal detergent selected from sulfonate, alkylphenol or salicylate, 0.1-0.75% of zinc thiophosphate, wherein the detergent is preferably a detergent containing alkaline earth metals.

USP5958848 discloses a low-chlorine, low-ash crankcase lubricating oil composition containing at least 1.5% chlorine-containing ashless dispersant and a detergent system, the detergent system comprising sulfonates and selected from alkylphenols, sulfurized alkylphenols and a phenate of alkyl salicylic acid, said phenate providing at least 0.0025 g of phenolic hydroxyl groups, wherein the sulfonate or metal salt is an overbasic salt, including not more than 0.008 g of carbonate, phenolic hydroxyl groups The gram equivalent ratio of the salt to the sulfonate is 1.4:1, the ratio of the total organometallic salt to the carbonate is 0.5:1, the chlorine content of the lubricating oil composition is 50ppm, the sulfate ash content is 1.2%, and the metal detergent includes at least An oil-soluble magnesium salt.

CN101108994A discloses a lubricating oil composition, wherein the phosphorus content is less than 0.9%, the sulfur content is less than 0.3%, the sulfate ash content is less than 1.0%, and the ashless dispersant is made by thermal "ene" reaction, and the overbased calcium sulfonate is used as The only detergent in lubricating oil, olefin copolymer viscosity index improver and other raw materials to prepare lubricating oil composition, the composition has good oxidation resistance, wear resistance and high temperature detergency.

USP5486300 discloses a lubricating oil composition, mainly comprising a lubricating oil base oil, at least one alkali metal salt of a high alkalinity organic acid, mainly a sodium or potassium salt of a high alkalinity sulfonic acid, in an amount of at least Contains 0.005 equivalent of alkali metal salt, wherein the metal ratio of the overbasic salt is 3-40, at least 1.13% of a dispersant, at least one dihydrocarbyl dithiophosphate. The patent does not determine the specific values of sulfur content, phosphorus content and sulfated ash.

USP6596672 discloses a low-ash lubricating oil composition containing multiple high-alkaline detergents and antioxidants, including: lubricating oil base oil, high-alkalinity calcium, magnesium, barium, strontium salts of 0.01-0.79% sulfate ash, 0.01 ~0.79% of high alkalinity magnesium or sodium salt, 0.1-1.5% of alkenyl-coupled shielded phenol antioxidant, 0.1-6% of at least one aromatic amine antioxidant, shielded phenol and aromatic amine content of at least 0.5 %, the sulfated ash content of the lubricating oil composition is 0.1-0.8%.

The prior art shows that the use of alkyl salicylate as a metal detergent can reduce the amount of metal additives in the system on the basis of satisfying various properties, and meet the requirements of low sulfur, low phosphorus and low ash content of oil products. However, the preparation process of alkyl salicylate is complicated and the product cost is high.

Calcium sulfonate and alkyl salicylate are compounded to prepare lubricating oil composition. Although the advantages of the two are combined, the additives are prone to turbidity or precipitation during the storage and use of the oil, which affects its further use.

Generally, a small amount of additives such as overbasic magnesium sulfonate, overbasic sodium sulfonate or overbasic potassium sulfonate will be introduced into compositions using overbasic calcium sulfonate as a metal detergent. The introduction of overbasic magnesium salt It has a certain impact on the high-temperature detergency of the composition, and the introduction of high-basic sodium sulfonate or potassium will reduce the anti-wear performance of the lubricating oil composition. At the same time, due to the high-basicity sodium or potassium salt anti-oxidation properties Due to the limitations of the formulation, more antioxidants need to be introduced, which affects the economy of the formula.

Contents of the invention

The object of the present invention is to provide a kind of lubricating oil composition of internal combustion engine, this lubricating oil composition has lower sulfur, Phosphorus and sulfated ash content.

The internal combustion engine lubricating oil composition provided by the present invention comprises a lubricating oil base oil and a sulfonate detergent, wherein the content of the sulfonate detergent is 0.8 to 1.5% by mass based on the composition, and the sulfonate detergent The additives include ultra-high-basic calcium sulfonate with a base value greater than 400 mgKOH/g, high-basic calcium sulfonate with a base value of 300-350 mgKOH/g and lithium sulfonate with a base value lower than 150 mgKOH/g.

The present invention selects three kinds of sulfonate detergents with different base values to form a sulfonate detergent instead of using alkyl salicylate detergents, in order to further improve the anti-friction and anti-wear properties of lubricating oil compositions , select the friction modifier containing esters to compound with the above-mentioned sulfonate detergent, and then prepare a lubricating oil composition with other additives, such as antioxidants, ashless dispersants, viscosity index improvers and pour point depressants, and base oils, The composition has good high-temperature detergency, anti-oxidation stability, anti-friction and anti-wear properties and alkali value retention, and has low sulfur and phosphorus contents. The additive used in the invention has low cost, is easy to obtain, and has good economy, and the prepared lubricating oil composition can satisfy the normal operation of the vehicle exhaust gas circulation (EGR) system while satisfying the normal operation of the engine.

Detailed ways

The lubricating oil composition of the present invention comprises lubricating oil base oil and three kinds of sulfonate detergents with different alkali values, and the use of these three sulfonate salts can meet the high temperature detergency and acid neutralization of the lubricating oil composition It meets the requirement of base number retention, and can reduce the usage amount of metal additives, thereby reducing the content of ash, sulfur and phosphorus in the lubricating oil composition. In order to make the composition meet the performance requirements of lubricating oil, it is preferable to add friction modifiers containing esters and other additives.

The three sulfonate detergents with different base values are ultra-high base value calcium sulfonate, high base value calcium sulfonate and low base value lithium sulfonate. The base value of the ultra-high base value calcium sulfonate is preferably 400-500 mgKOH/g, the base value of the over-base value calcium sulfonate is preferably 300-330 mgKOH/g, and the base value of lithium sulfonate is preferably 50-180 mgKOH/g.

The mass ratio of the ultra-high base value calcium sulfonate, overbase value calcium sulfonate and lithium sulfonate is 1:2-3:1-2.

In order to improve the anti-friction and anti-friction properties of the lubricating oil composition, it is preferable to combine the sulfonate detergent of the present invention with a friction modifier containing an ester functional group. Therefore, preferably, in the lubricating oil composition It also includes 0.1-0.4% by mass, preferably 0.15-0.3% by mass, of a friction modifier containing an ester functional group.

The friction modifier containing ester functional group is prepared by esterification reaction of C ₁₀ -C ₄₀ alkyl carboxylic acid or alkenyl carboxylic acid and C ₂ -C ₅ alcohol, and the alcohol can be a monohydric alcohol , diols or triols. The friction modifier is preferably C ₁₆ -C ₂₄ alkyl carboxylated ethylene glycol ester, butyl stearate, diethyl oleate or glycerol oleate.

The sulfonic acid contained in the sulfonate detergent is alkylbenzenesulfonic acid or petroleum sulfonic acid, that is, the sulfonate is synthesized from sulfonic acid. The benzene ring of the alkylbenzene sulfonic acid or petroleum sulfonic acid may have one or more alkyl substituents, the substituents are linear or branched alkyl groups, and the total carbon number of the substituted alkyl groups on the benzene ring is 10- 30, preferably 12-28.

In order to make the lubricating oil composition reach the specified performance index, the composition should also contain an appropriate amount of ashless dispersant, antioxidant, tackifier and pour point depressant. Preferably, the composition also includes 1.0-3.0% by mass of nitrogen-containing ashless dispersant, 0.5-1.5% by mass of antioxidant, 5-10% by mass of viscosity index improver and 0.1-1.0% by mass of pour point depressant .

The nitrogen-containing ashless dispersant is preferably a polyisobutylene succinimide dispersant, and its molecular weight is preferably 1000-3000. The dispersant is prepared by alkylation of polyisobutylene and maleic anhydride, and amination reaction with amine-containing compounds such as polyene polyamines. Dispersants can be mono-, bis- or polysuccinimide ashless dispersants. Ashless dispersant in lubricating oil can effectively shield the colloidal colloids of carbon deposits from aggregating and preventing them from depositing on the metal surface.

The antioxidant is preferably zinc dialkyl dithiophosphate, and its synthesis method is: first react alcohol with P ₂ S ₅ to generate dialkyl dithiophosphoric acid, and then react with zinc oxide to generate dialkyl dithiophosphate. Zinc thiophosphate, the alkyl group can be a straight chain alkyl group of _C4 , a straight chain alkyl group of _C8 , or a heterogeneous alkyl group of _C4 . Zinc salts of different alkyl groups are selected according to the working requirements of the lubricating oil composition. The main function of dialkyl dithiophosphate zinc salt is to decompose the peroxide formed in the reaction and inhibit the oxidation of oil.

The viscosity index improver is preferably an ethylene-propylene copolymer with a number average molecular weight of 50,000-100,000. The ethylene content in the ethylene-propylene copolymer is preferably 40 to 60% by mass, and the propylene content is preferably 60 to 40% by mass. Using a viscosity index improver to adjust the viscosity of lubricating oil can improve the working efficiency of the internal combustion engine and save fuel.

The pour point depressant is preferably a C ₈ -C ₁₂ alpha olefin polymer, which is obtained by polymerizing a C ₈ -C ₁₂ alpha olefin. The pour point depressant can adsorb on the wax in the oil, destroy the network structure of the wax at low temperature, and ensure the oil can flow at low temperature.

The base oil used in the composition of the present invention is mainly hydrocarbon lubricating oil, which can be type I oil, type II oil, type III oil, or type IV oil, or a mixture of the above types. The base oil mainly meets the lubrication requirements. The viscosity of the oil composition requires that the 100°C viscosity of the lubricating base oil be 3-20 mm ² /s, preferably 9-17 mm ² /s. The choice of base oil should also consider other performance requirements of the composition, such as Nock evaporation loss and viscosity index.

The lubricating oil composition provided by the invention is mainly used for lubricating gasoline engines and diesel engines.

The present invention will be further described in detail below by examples, but the present invention is not limited thereto.

The performance evaluation method of the composition prepared in the example is as follows:

High temperature detergency:

The paint and coke plate experiments were carried out on the L-1 type plate coke generator. Coking: plate temperature/oil temperature=320°C/100°C, time 2 hours, stop/start time=45 seconds/15 seconds. Lacquer finish: board temperature/oil temperature=300°C/150°C, time 2 hours, continuous.

The test was carried out on the L-A type detergency tester to investigate its high temperature detergency. Plate temperature/oil temperature=300°C/100°C, time 1 hour, stop/start time=40 seconds/20 seconds. Oil drop speed 1.0ml/min.

Antioxidant stability:

Measured with TA5000DSC2910 thermal analyzer, and used PDSC (Pressure Differential Scanning Calorimeter pressure differential scanning calorimeter) method to investigate the thermal oxidation stability of the oil.

Oil film rupture load and friction coefficient:

Evaluation of anti-friction and anti-wear properties of GB/T3142-82 lubricants.

Wear spot diameter:

SH/T 0189 Determination of anti-wear performance of lubricating oil (four-ball machine method).

Base value retention:

In a 200ml test tube, when the oil temperature is 150°C, air is introduced at a ventilation rate of 10ml/min, and the change of the base value is measured after 2 hours.

Example 1~3

Compositions of the present invention are formulated.

150SN, 500SN, and 150BS were prepared into base oil at a mass ratio of 14:5:1. The viscosity at 100°C was 14.5mm ² /s, and its performance met the requirements of 15W/40 base oil.

Sulfonate detergents, friction modifiers, antioxidants, ashless dispersants, viscosity index improvers and pour point depressants are added to the prepared base oil to prepare lubricating oil compositions. The names and indicators of the additives used are as follows:

Sulfonate detergents:

Ultra-high base value calcium sulfonate: a base value of 405 mgKOH/g, a calcium content of 14.5% by mass, and a sulfur content of 1.43% by mass.

High base value calcium sulfonate: a base value of 311 mgKOH/g, a calcium content of 10.2% by mass, and a sulfur content of 1.8% by mass.

Low base value lithium sulfonate: a base value of 135 mgKOH/g, a lithium content of 1.91% by mass, and a sulfur content of 2.07% by mass.

Friction modifiers:

Dimer acid ethylene glycol ester, the _C18 alkyl carboxylate ethylene glycol ester that adopts 1014 dimer acid synthesis of Emery company, acid value 26mgKOH/g.

Diethyl oleate, the acid value is 38mgKOH/g.

Antioxidants:

Zinc dialkyldithiophosphate (T202), zinc content 8.2 mass%, sulfur content 15.1 mass%, phosphorus content 8.2 mass%, content in the composition is 0.9 mass%.

Ashless Dispersant:

Monosuccinimide (T151) has a nitrogen content of 2.1% by mass, a base value of 50 mgKOH/g, and a content of 1.5% by mass in the composition.

Viscosity Index Improver (T613):

The ethylene-propylene copolymer has a molecular weight Mn of 85,000, an ethylene content of 51% by mass, a propylene content of 49% by mass, and the content of the ethylene-propylene copolymer in the composition is 7.0% by mass.

Pour point depressant (T803):

The α-olefin polymer has an Mn molecular weight of 2352, and its content in the composition is 0.3% by mass.

The content of sulfonate detergent and friction modifier used in each example in the composition is shown in Table 1, the sulfur and phosphorus content of the composition, detergency, oxidation resistance, friction reduction and wear resistance and base number retention evaluation results See Table 2.

Comparative example 1-5

The composition is prepared according to the method of example 1, the difference is that the detergent and friction modifier added are different, the content of sulfonate detergent and friction modifier used in each comparative example in the composition is shown in Table 1, the sulfur, the friction modifier of the composition See Table 2 for the evaluation results of phosphorus content, detergency, oxidation resistance, anti-friction and anti-wear properties and base number retention.

The alkali value of the high alkalinity magnesium sulfonate adopted in the comparative example is 402mgKOH/g, the magnesium content is 9.3% by mass, and the sulfur content is 1.42% by mass.

The high base value sodium sulfonate had a base value of 407 mgKOH/g, a sodium content of 17.0% by mass, and a sulfur content of 1.53% by mass.

Table 1

Table 2

It can be seen from the data in Table 2 that the sulfated ash content of the lubricating oil composition prepared by the present invention is less than 0.8% by mass, the content of phosphorus is less than 0.08% by mass, and the content of sulfur is less than 0.2% by mass. Wear resistance and base number retention, wherein the composition formulated in Example 1 without friction modifier has slightly poorer friction reduction and wear resistance. The composition prepared in Comparative Example 1 did not use lithium sulfonate as a detergent, and the high-temperature detergency was poor. The composition prepared in Comparative Example 2 did not use calcium sulfonate with an ultra-high base value, and the alkali value retention decreased rapidly. The composition prepared in Comparative Example 3 has poor detergency at high temperature because only ultra-high base value calcium sulfonate is used. The composition prepared in comparative example 4 uses magnesium sulfonate with high alkalinity instead of lithium sulfonate, and its high-temperature detergency is poor. The composition prepared in comparative example 5 adopts sodium sulfonate with high alkalinity instead of lithium sulfonate. Oxidation stability is poor, and sulfated ash is the largest.

Claims (9)

1. a lubricant composition for internal combustion engines, comprise lubricant base and take the sulfonate detergent that content that composition is benchmark is 0.8～1.5 quality %, 0.15 the friction improver that contains ester group functional group of～0.3 quality %, described sulfonate detergent comprises that base number is greater than the overbased calcium sulphonate of 400mgKOH/g, the calcium sulfonate with high base number that base number is 300～350mgKOH/g and base number are lower than the Sulfonic Lithium of 150mgKOH/g, described overbased calcium sulphonate, the mass ratio of calcium sulfonate with high base number and Sulfonic Lithium is 1: 2～3: 1～2, described friction improver is C ₁₆～C ₂₄alkyl carboxylic acid glycol ester, butyl stearate, oleic acid diethyl alcohol ester or olein.

2. according to composition claimed in claim 1, it is characterized in that sulfonic acid used in sulfonate detergent is alkyl benzene sulphonate (ABS) or mahogany acid.

3. according to composition claimed in claim 2, the total carbon number that it is characterized in that the substituted alkyl on benzene ring of alkyl benzene sulphonate (ABS) is 10～40.

4. according to composition claimed in claim 1, it is characterized in that in composition also comprising the nitrogenous ashless dispersant of 1.0～3.0 quality %, the oxidation inhibitor of 0.5～1.5 quality %, the viscosity index improver of 5～10 quality % and the pour point depressant of 0.1～1.0 quality %.

5. according to composition claimed in claim 4, it is characterized in that described nitrogenous ashless dispersant is polyisobutene succinimide type dispersion agent.

6. according to composition claimed in claim 4, it is characterized in that described oxidation inhibitor is zinc dialkyl dithiophosphate.

7. according to composition claimed in claim 4, it is characterized in that described viscosity index improver is the ethylene-propylene copolymer that number-average molecular weight is 50000～100000.

8. according to composition claimed in claim 4, it is characterized in that described pour point depressant is C ₈～C ₁₂alpha-olefin polymers.

9. according to composition claimed in claim 1, it is characterized in that 100 ℃ of viscosity of lubricant base are 3～20mm ²/ s.