CN1523088A - low ash gas engine lubricating oil composition - Google Patents

Abstract

The low-ash gas engine lubricating oil composition comprises base oil, a pour point depressant, a viscosity index improver, an anti-foaming agent, a metal detergent composition, a polyolefin succinimide ashless dispersant, an oxidation and corrosion inhibitor and an antiwear agent, wherein the metal detergent composition is a mixture of a high-base-number metal salt and a medium-base-number metal salt or a low-base-number metal salt. The lubricating oil composition has excellent lubricating performance, cleaning performance, dispersing performance, anti-nitration performance, anti-oxidation and anti-corrosion performance and antiwear performance, and low ash content (0.1-0.6 wt% of sulfated ash content), and can prevent the pre-ignition of gas engine.

Description

Low ash gas engine lubricating oil composition

(1) Technical field

The invention relates to a lubricating oil composition, especially a low ash gas engine lubricating oil composition with excellent lubricating performance, cleaning performance, dispersing performance, anti-nitrification performance, anti-oxidation and anti-corrosion performance and anti-wear performance.

(2) Background technology

In recent years, with the attention to environmental protection, gas engine vehicles fueled by liquefied petroleum gas LPG and compressed natural gas CNG have developed rapidly. A notable feature of gaseous fuel is high combustion temperature, which accelerates the formation of _NOx , and _NOx enters the crankcase with the blow-by gas in the engine cylinder, making the lubricating oil in the crankcase more likely to be nitrated, thereby shortening the service life of the lubricating oil. In addition, lubricating oil is easy to form deposits in gaseous fuel engines, but gaseous fuels have insufficient cleaning ability for engine deposits. When the ash content of lubricating oil is too high, the tendency to form deposits is more obvious. A large amount of deposits can cause The pre-ignition of the gas engine causes the engine to work disorderly. Therefore, lubricating oils suitable for gas engines should have good detergency and dispersion properties, anti-oxidation properties, anti-nitrification properties and anti-wear properties, and at the same time, the sulfate ash content of oil products should be controlled. A classification of gas engine oils based on the sulfated ash content of the oil is widely accepted by lubricant researchers and manufacturers and marketers, and is listed in Table 1.

Table 1 Gas engine oil classification type Sulfated Ash Content, %, Weight Ratio Ashless type Low ash type Medium ash type High ash type <0.10.1-0.60.6-1.5>1.5

The selection of a gas engine is mainly determined according to the cleanliness of the fuel gas, road conditions, engine workload and other factors. It is suitable to use ash-free or low-ash type oil for clean fuel gas engine vehicles driving in the city.

U.S. Patent No. 6,001,780 has introduced a kind of polyolefin or polyolefin succinimide dispersant, boronated polyolefin or boronated polyolefin succinimide dispersant and a small amount of antioxidant, antiwear agent Ashless (less than 0.1% sulfated ash by weight) lubricating oil formulation for natural gas engines.

U.S. Patent No. 5,726,133 has introduced a kind of low ash type natural gas engine oil and its additive system that adopts the sulfate ash of specific detergent component to be divided into 0.1%-0.6% (weight ratio), and its additive system contains a An alkali metal salt with a base number not higher than 250 mgKOH/g and an alkali metal salt with a lower base number in a ratio of 1.2:1 to 2.3:1.

U.S. Patent US6,191,081 introduces a long-life medium-ash and high-ash gas engine oil with enhanced anti-nitrification performance. The formula contains high alkali value, medium alkali value and low alkali value (or neutral salt) cleaning The detergent component is composed of an agent complex and at least one of the medium base number or low base number detergent is a metal salicylate.

Among Chinese patents, there is currently no patent related to gas engine lubricating oil.

(3) Contents of the invention

The object of the present invention is aimed at the characteristics of the gas engine itself and the characteristics of the gaseous fuel combustion product, and proposes a low ash (sulfate ash content of 0.1%-0.6 %, weight ratio) gas engine special lubricating oil composition.

The lubricating oil composition includes base oil with lubricating properties, specific metal detergent components, polyolefin succinimide ashless dispersant, antioxidant and anticorrosion agent, antiwear agent, antifoaming agent, pour point depressant agent, viscosity index improver and other components.

The main component of the low-ash gas engine lubricating oil composition of the present invention is a base oil with lubricating properties, and the base oil may be a solvent refining process base oil, polyalphaolefin synthetic oil or a mixture of the two. For the lubricating oil composition with a viscosity grade of 10W/30, the kinematic viscosity range of the suitable base oil component is 4-10mm ² /s at 100°C; for the lubricating oil composition with a viscosity grade of 15W/40, the suitable base oil component is The kinematic viscosity at 100°C is in the range of 5-15mm ² /S. The content of the base oil component in the lubricating oil composition is at least 70% by weight.

The low ash gas engine lubricating oil composition of the present invention contains a specific metal salt detergent component, which contains: (1) at least one high base number with a total base number (TBN) range of not less than 270mgKOH/g Or a metal salt detergent with an ultra-high base value; (2) at least one metal salt detergent with a total base number ranging from 20-180 mgKOH/g. The above-mentioned metal salt detergent can be an alkyl salicylate, sulfonate, alkyl phenate or sulfurized alkyl phenate of a metal, at least one of which is an alkyl salicylate; and the metal can be sodium, magnesium , calcium, containing at least one overbase or ultra overbase magnesium salt detergent. The content range of the active component of the metal salt detergent in the lubricating oil composition is 0.3%-2.0% (weight ratio).

The low-ash gas engine special lubricating oil composition of the present invention contains polyolefin succinimide ashless dispersant, and the ashless dispersant can be (1) single polyolefin succinimide, (2) double polyolefin butyl Diimide, (3) a mixture of the two. The above-mentioned ashless dispersant can be boronated polyolefin succinimide, or macromolecular polyolefin succinimide, with a molecular weight in the range of 600-3000. The content range of the active component of the ashless dispersant in the lubricating oil composition is 1.0%-4.5% (weight ratio).

The low-ash gas engine lubricating oil composition of the present invention contains a certain antioxidant and anticorrosion agent component, which can be (1) aromatic amine antioxidant, (2) shielding phenolic antioxidant, (3) ) a mixture of the two. The content range of the active component of the antioxidant and anticorrosion agent in the lubricating oil composition is 0.05%-1.5% (weight ratio).

The low ash gas engine lubricating oil composition of the present invention comprises antiwear component, and this component can be the dithiophosphate of metal zinc or molybdenum, such as zinc dialkyl dithiophosphate (ZDDP), also can be A mixture of zinc and molybdenum salts. The content range of the antiwear active component in the lubricating oil composition is 0.3%-2.0% (by weight).

The low-ash gas engine lubricating oil composition of the present invention also includes the following conventional additives:

(a) A carboxylic acid derivative that can be used in a lubricating oil composition and has the effect of lowering the freezing point of the lubricating oil composition, such as polymethacrylate, the content of this component in the lubricating oil composition ranges from 0.1% to 0.7% (weight ratio); (b) a macromolecular polymer that can be used in lubricating oil compositions to improve the viscosity index performance of lubricating oil compositions, such as ethylene-propylene copolymers, polymethacrylates, etc., the group The content range of the component in the lubricating oil composition is 2.5%-11.5% (weight ratio); (c) an antifoaming agent, such as methyl silicone oil, etc., the content range of this component in the lubricating oil composition is 0.001% %-0.05% (by weight).

The low-ash gas engine lubricating oil composition of the present invention is used in the vehicle gas engine, and has the following properties: (1) effectively improve the lubrication of the engine, ensure the normal operation of the engine, reduce friction, and reduce frictional power loss; (2) in the engine During operation, especially in stop-start or idling conditions, it can significantly reduce the formation of sludge and the deposition of paint film, keep the lubricating parts of the engine clean, and ensure the normal oil supply of the engine; (3) the low ash feature can significantly reduce The deposition of organometallic compounds at the intake valve of the engine can effectively prevent the gas engine from prematurely igniting; (4) effectively prolong the service life of the engine.

Relevant data show that most provinces in my country are currently committed to promoting alternative fuel vehicles fueled by liquefied petroleum gas and compressed natural gas, especially in large cities such as municipalities directly under the central government and provincial capitals. Gasoline and liquefied petroleum gas or compressed natural gas are fueled dual-fuel vehicles. Therefore, the gas engine lubricating oil product involved in the invention has a good market prospect.

(4) Specific implementation methods

Example 1: Preparation of 10W/30 gas engine lubricating oil, see Table 2 for component contents, and see Table 3 for the data thus obtained.

Table 2 components content,% Base oil component HVI100SNMVI150BS pour point depressant polymethacrylate viscosity index improver ethylene propylene copolymer 81.06.90.36.5 Anti-foaming agent Methyl silicone oil Detergent Ultra-high base value magnesium salicylate detergent Detergent High base value calcium salt salicylate Ashless dispersant Polyolefin monosuccinimide Antioxidant Alkylaniline Anti-wear agent Dialkyl Zinc dithiophosphate 0.0010.90.62.80.50.5

table 3 project tentative indicators measured value experiment method Sulfate ash content, % base number, mgKOH/g100°C kinematic viscosity, ^mm2 /s-20°C dynamic viscosity, mPa·s boundary pumping temperature, °C flash point (opening), °C pour point, °C high temperature high shear viscosity (150°C, 10 ⁶ s ^-1 ) mPa·s foam property (foam tendency/foam stability), mL/mL Sulfur content at 24°C after 93.5°C at 24°C, %(m/m) Phosphorus content, %(m/m ) moisture, %(m/m) sediment, %(m/m) plate coke generator test ¹ , coke weight, mgSDT test ² , mud spot/oil spot, % internal combustion engine oil high temperature oxidation and bearing bush corrosion test ³ bearing bush weight loss , mg piston skirt paint film score, 0.1-0.63.0-6.09.3-<12.5 not more than 3500 not more than -25 not less than 205 not more than -30 not less than 2.9 not more than 25/0 not more than 150/0 not more than 50/0 report report Not greater than traces Not greater than 0.01 Not greater than 40 Not less than 9.0 0.5163.7110.863000 less than -25208 - 303.360/05/00/00.360.051 trace 0.009142.159.027.99.5 GB/T2433SH/T0251GB/T265GB/T6538GB/T9171GB/T3536GB/T3535SH/T0618GB/T12579SH/T0303SH/T0296GB/T260GB/T6531Q/SH018·0235Q/SH018·0194SH/T0265

Note: 1 Expressed by the coke weight on the test plate, the smaller the coke weight, the better the piston cleaning performance of the composition.

2 Expressed by the percentage of diffused mud spots/oil spots, the larger the value, the better the dispersion performance of the composition.

3 This test is an engine test, and the results of this test show that the composition according to this embodiment has good performance on the engine.

Example 2: Prepare 15W/40 gas engine lubricating oil, see Table 4 for the component contents, and see Table 5 for the data thus obtained.

Table 4 components content,% Base Oil Component HVI200SN Pour Point Depressant Viscosity Index Improver Antifoam Agent Metal Detergent Polyisobutylene Succinimide Ashless Dispersant Antioxidant Anticorrosion Agent Antiwear Agent 85.90.48.00.0021.13.30.70.6

table 5 project tentative indicators measured value experiment method Sulfate ash content, % base number, mgKOH/g100°C kinematic viscosity, ^mm2 /s-15°C dynamic viscosity, mPa·s boundary pumping temperature, °C flash point (opening), °C pour point, °C high temperature high shear viscosity (150°C, 10 ⁶ s ^-1 ) mPa·s foam property (foam tendency/foam stability), mL/mL Sulfur content at 24°C after 93.5°C at 24°C, %(m/m) Phosphorus content, %(m/m ) moisture, %(m/m) sediment, %(m/m) plate coke generator test ¹ , coke weight, mgSDT test ² , mud spot/oil spot, % 0.1-0.63.0-6.012.5-<16.3 not more than 3500 not more than -20 not less than 215 not more than -23 not less than 3.7 not more than 25/0 not more than 150/0 not more than 50/0 report report not greater than traces not greater than 0.01 0.4823.5414.863200 less than -20220-254.1610/025/010/00.320.063 trace 0.00597.258.5 GB/T2433SH/T0251GB/T265GB/T6538GB/T9171GB/T3536GB/T3535SH/T0618GB/T12579SH/T0303SH/T0296GB/T260GB/T6531Q/SH018·0235Q/SH018·0194

Note: See Example 1.

Claims (9)

1. A lubricating oil composition for a gas engine with low ash content, characterized in that the composition contains (A) at least 70% (weight) base oil; (B) metal salt detergent mixture, in the lubricating oil composition The content is 0.3%-2.0% (weight); (C) at least one polyolefin succinimide ashless dispersant, the content in the lubricating oil composition is 1.0%-4.5% (weight); (D) At least one antioxidant and anticorrosion agent, the content of which is 0.05%-1.5% (weight) in the lubricating oil composition; (E) anti-wear agent, the content of which is 0.3%-2.0% (weight) in the lubricating oil composition; (F) carboxylic acid derivative pour point depressant, the content in the lubricating oil composition is 0.1%-0.7% (weight); (G) macromolecular polymer viscosity index improver, the content in the lubricating oil composition is 4.0% -10.0%; (H) an antifoaming agent, the content of which is 10-15 μg/g in the lubricating oil composition. 2. The lubricating oil composition for a low-ash gas engine according to claim 1, wherein (A) is a solvent-refined base oil or a polyalphaolefin synthetic oil or a mixture of the two. 3. according to the lubricating oil composition of the described gas engine of low ash content of claim 1, it is characterized in that comprising in the metal salt detergent mixture B: (1) at least one metal salt with high alkali value or super high alkali value Detergent, its total base number range is not less than 270mgKOH/g; (2) at least one medium or low base number metal salt detergent, its total base number range is 20-180mgKOH/g. 4. according to the lubricating oil composition of the described low-ash gas engine of claim 3, it is characterized in that in the metal salt detergent mixture, the metal component of detergent is metal calcium or sodium or magnesium, wherein at least one is peralkali Magnesium salts with high or ultrahigh base numbers. 5. according to the lubricating oil composition of the described gas engine of low ash content of claim 3, it is characterized in that in metal salt detergent mixture, detergent is salicylate, sulfonate or phenate of metal, wherein at least one One is salicylates. 6. according to the lubricating oil composition of the described gas engine of low ash content of claim 1, it is characterized in that ashless dispersant C is single polyolefin succinimide or double polyolefin succinimide or aforementioned two mixture. 7. according to the lubricating oil composition of the described gas engine of low ash content of claim 6, it is characterized in that single, double polyolefin succinimide is the polyolefin succinimide of boronization or molecular weight range is at 600- 3000 polyolefin succinimide. 8. The lubricating oil composition for a low-ash gas engine according to claim 1, wherein the antioxidant and anticorrosion agent D is an aromatic amine antioxidant or a shielded phenolic antioxidant or a mixture of the two. 9. according to the lubricating oil composition of the described low-ash gas engine of claim 1, it is characterized in that antiwear agent E is the dithiophosphate of metal zinc or the dithiophosphate of metal molybdenum or the mixture of the two .