Low ash non-road compression ignition engine lubricating oil and additive concentrate and method of making

Abstract

The application provides a low-ash non-road compression ignition engine lubricating oil and an additive mother liquor and a preparation method thereof, and relates to the technical field of lubricating oil. The mother liquor comprises a polyisobutylene succinimide ashless dispersant, a metal detergent composed of low-sulfur high-alkali overbased magnesium salicylate and low-sulfur high-alkali overbased calcium salicylate, a friction modifier system containing organic molybdenum, an organic borate ester friction modifier and a polar ester film forming agent, a rust inhibitor and corrosion inhibitor composed of succinic acid half ester rust inhibitor and benzotriazole corrosion inhibitor, a modified polyether demulsifier, a zinc-containing and phosphorus-containing anti-wear agent of zinc dialkyldithiophosphate, a phosphoric acid ester ashless anti-wear agent and an antioxidant. The mother liquor is used for preparing a low-ash compression ignition engine lubricating oil under the constraint of low-SAPS, and is beneficial to the combination of soot dispersion, friction and wear resistance, oil-water separation, rust and corrosion prevention and post-processing compatibility.

Description

Technical Field

[0001] This invention relates to the field of lubricating oil technology, and in particular to a low-ash off-road compression ignition engine lubricating oil, its additive mother liquor, and its preparation method. Background Technology

[0002] Compression-ignition internal combustion engines for non-road applications are widely used in agricultural machinery, construction machinery, non-road mobile machinery, forestry machinery, and mining machinery. These engines typically operate under complex conditions, harsh environments, high loads, and frequent hot and cold cycles, placing high demands on the overall performance of the lubricating oils used.

[0003] Specifically, non-road compression-ignition internal combustion engines present the following typical usage characteristics and technical challenges: (a) High smoke and soot, high load and long cycle operation.

[0004] The equipment often operates under low speed, high torque, and long-term continuous conditions, resulting in incomplete combustion and high soot production. If the lubricating oil's dispersing and cleaning abilities are insufficient, it can easily cause problems such as abnormally high oil viscosity, carbon buildup in piston ring grooves, increased deposits in the combustion chamber, and filter clogging.

[0005] (ii) Exhaust gas aftertreatment device and low-SAPS constraint.

[0006] With the upgrading of emission regulations, some new non-road engines have been equipped with or have been designed with exhaust aftertreatment systems such as particulate filters and selective catalytic reduction devices, imposing strict limits on the sulfate ash, phosphorus, and sulfur content in lubricating oils. The traditional approach of improving extreme pressure anti-wear performance and detergent neutralization capacity by increasing the amount of zinc- and phosphorus-containing anti-wear agents and high-metal detergents is incompatible with the compatibility of aftertreatment systems; however, simply reducing the amount of metal detergents and zinc- and phosphorus-containing anti-wear agents can easily lead to a decrease in total base number retention, poor soot dispersion stability, and insufficient boundary lubrication protection.

[0007] (iii) High humidity, water content and intermittent parking conditions.

[0008] Agricultural machinery, paddy field machinery, and some construction machinery often operate in high-humidity, high-dust environments, making it easy for lubricating oil to become contaminated with moisture and impurities. Additionally, some equipment exhibits significant seasonal or intermittent usage characteristics. Conventional high-dispersion, high-surface-activity systems often weaken demulsification performance, forming a stable emulsion layer that can induce corrosion, filter blockage, and lubrication failure. If rust prevention and corrosion inhibition systems are insufficient, critical metal components such as cylinder liners, bearings, tappets, and valve mechanisms are more prone to rust and pitting during periods of inactivity.

[0009] (iv) High-sulfur fuel scenario for existing equipment.

[0010] A small number of existing equipment may still use fuels with a high sulfur content, and the acidic substances produced after combustion will accelerate the consumption of total base number (TBN). If the detergent and ashless dispersant are not properly matched, it will lead to insufficient neutralization capacity, causing corrosion and wear of metal parts and sludge deposition. This scenario mainly corresponds to existing equipment without aftertreatment or with low aftertreatment sensitivity, and is not considered a preferred implementation direction of this application.

[0011] Currently, most low-ash diesel engine oils focus on meeting aftertreatment compatibility requirements by reducing the amount of metal detergents and zinc- and phosphorus-containing anti-wear agents, or emphasize conventional friction reduction, anti-wear, and detergency and dispersancy properties. However, under low-SAPS constraints, it is often difficult to simultaneously achieve soot dispersion, adequate total base number reserve, demulsification, rust prevention and corrosion inhibition, and boundary lubrication protection. Especially under high humidity, water content, and intermittent parking conditions, conventional high-dispersion or high-surface-activity systems are prone to forming stable emulsion layers and inducing corrosion, while simply reducing metal and phosphorus content weakens the oil's detergency retention and anti-wear properties.

[0012] Therefore, there is an urgent need to develop a low-ash non-road compression ignition engine lubricant additive masterbatch, so that the lubricant formulated from it can meet the compatibility requirements of exhaust aftertreatment systems while also possessing good soot dispersion ability, moderate total base number reserve, friction reduction and anti-wear properties, oil-water separation performance, and rust and corrosion prevention properties. It should be suitable for forming low-ash lubricants with viscosity grades such as SAE 15W-40, 10W-40, 5W-40, 10W-30, and 5W-30, preferably formulated to meet the performance grade requirements of API CK-4, thus making it suitable for non-road compression ignition internal combustion engines equipped with or designed with exhaust aftertreatment devices.

[0013] In view of this, the present invention is hereby proposed. Summary of the Invention

[0014] The primary objective of this invention is to provide a low-ash non-road compression ignition engine lubricating oil additive mother liquor. The mother liquor has a stable structure and good compatibility, and can simultaneously achieve soot dispersion, moderate total base number reserve, friction reduction and wear resistance, oil-water separation, and rust and corrosion prevention performance under the constraints of low sulfate ash, low phosphorus, and low sulfur.

[0015] The term "low-SAPS constraint" as used herein refers to the restrictions imposed on the sulfate ash, phosphorus, and sulfur content of lubricating oil to ensure compatibility with exhaust aftertreatment systems. Unless otherwise stated, in this application, the low-SAPS constraint specifically refers to a finished lubricating oil with a sulfate ash content not exceeding 1.0% by mass, a phosphorus content not exceeding 0.08% by mass, and a sulfur content not exceeding 0.4% by mass. Preferably, the lubricating oil is used in non-road compression-ignition internal combustion engines equipped with or pre-installed with diesel particulate filters (DPF), selective catalytic reduction (SCR) devices, or other exhaust aftertreatment devices. It should be noted that different standard systems may classify this term differently; in this application, the numerical values ​​defined above shall prevail.

[0016] The second objective of this invention is to provide a low-ash off-road compression ignition engine lubricating oil formulated using the above-mentioned additive mother liquor.

[0017] A third objective of this invention is to provide a method for preparing the aforementioned lubricating oil.

[0018] It should be noted that the low-ash non-road compression ignition engine lubricating oil additive mother liquor provided by the present invention contains compression ignition internal combustion engine lubricating oil whose performance status can be monitored during use using the three-channel fluorescence diagnostic enhancer disclosed in application number: 202610570553.3.

[0019] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a low-ash off-road compression ignition engine lubricating oil additive mother liquor, which, based on the total mass of the mother liquor, comprises: 13.0–15.5 wt% of polyisobutylene succinimide type ashless dispersant; The metal cleaning agent is 6.0-8.0 wt%, which is composed of low-sulfur, high-alkalinity, superalkaline magnesium salicylate and low-sulfur, high-alkalinity, superalkaline calcium salicylate. The friction modifier system comprises 4.2–5.0 wt%, wherein the friction modifier system consists of an organomolybdenum friction modifier, an organoborolate friction modifier, and a polar ester film-forming agent; The rust and corrosion inhibitor is 1.1 to 1.5 wt%, which is composed of succinic acid half-ester rust inhibitor and benzotriazole corrosion inhibitor; Modified polyether demulsifier 0.25–0.45 wt%; Zinc- and phosphorus-containing dialkyl dithiophosphate anti-wear agents, 0.50–0.85 wt%; Phosphate ester-based ashless anti-wear agent 0.80–1.10 wt%; Antioxidant 0.90–1.30 wt%, wherein the antioxidant is composed of aromatic amine antioxidants and hindered phenolic antioxidants; And carrier oil, with the balance replenished to 100 wt%.

[0020] Furthermore, the mass ratio of the ashless dispersant to the metal detergent is (1.9–2.3):1.

[0021] Furthermore, the mass ratio of the low-sulfur, high-alkalinity superalkaline magnesium salicylate to the low-sulfur, high-alkalinity superalkaline calcium salicylate is (3.3-3.7):1, preferably 3.5:1.

[0022] Furthermore, the organic molybdenum friction modifier is molybdenum dialkyl dithiophosphate; The organoboroester friction modifier is an alkylboronate; The polar ester film-forming agent is a dialkyl sebacate; The mass ratio of the organic molybdenum friction modifier, the organic borate ester friction modifier, and the polar ester film-forming agent is 1:(0.95-1.05):(0.80-0.95), and the mass percentages of the three in the mother liquor are 1.45-1.75 wt%, 1.45-1.75 wt%, and 1.25-1.55 wt%, respectively.

[0023] Furthermore, the mass ratio of the succinic acid half-ester rust inhibitor to the benzotriazole corrosion inhibitor is (3.8-4.2):1, and the content of the modified polyether demulsifier is 0.30-0.40 wt%.

[0024] Furthermore, the content of the zinc- and phosphorus-containing dialkyl dithiophosphate zinc anti-wear agent is 0.60–0.80 wt%; The content of the phosphate ester-based ashless anti-wear agent is 0.90–1.05 wt%; The antioxidant content is 1.00-1.15 wt%, and the mass ratio of the aromatic amine antioxidant to the hindered phenolic antioxidant is 3:2.

[0025] Furthermore, the mother liquor also contains 18.5–20.0 wt% of a shear stability ethylene-propylene copolymer viscosity index improver, 0.40–0.60 wt% of a polymethacrylate pour point improver, and 0.01–0.03 wt% of a polydimethylsiloxane defoamer, and the carrier oil comprises any combination of the following: (a) A combination of Group III base oils, alkyl naphthalenes, and synthetic esters; (b) A combination of PAO synthetic base oil, alkyl naphthalene and synthetic ester.

[0026] The present invention provides a low-ash off-road compression ignition engine lubricating oil, the lubricating oil comprising a base oil and the above-mentioned lubricating oil additive mother liquor; The amount of mother liquor added is 13% to 15% of the total mass of the lubricating oil, and the lubricating oil has the following properties: sulfate ash content ≤1.0 wt%, phosphorus content ≤0.08 wt%, sulfur content ≤0.4 wt%, total base value 7.5 to 10.5 mgKOH / g, kinematic viscosity at 100℃ 9.3 to 16.3 mm² / s, and high-temperature high-shear viscosity ≥3.5 mPa·s.

[0027] Furthermore, the base oil includes Group II base oil, or a combination of Group I and Group II base oil, or a combination of Group II and Group III base oil, and the viscosity grade of the lubricating oil is SAE 15W-40, 10W-40, 5W-40, 10W-30 or 5W-30.

[0028] Furthermore, the lubricating oil is preferably formulated for API CK-4 application scenarios, and apart from the lubricating oil additive mother liquor, no additional compound additive package is added to provide detergency, anti-wear, anti-oxidation, demulsification or rust prevention functions.

[0029] The present invention provides a method for preparing the above-mentioned lubricating oil, the method comprising: adding the lubricating oil additive mother liquor to base oil at an amount of 13% to 15% of the total mass of the lubricating oil, stirring at 200 to 800 r / min at 60 to 80°C, and performing shear homogenization treatment for 20 to 40 min, preferably with a shear linear velocity ≥ 5 m / s, to obtain the lubricating oil.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: The low-ash off-road compression ignition engine lubricating oil additive mother liquor provided by this invention has the following technical effects: (i) By increasing the relative proportion of ashless dispersant in the mother liquor and controlling its mass ratio with metal detergent, the present invention enables the low-ash lubricating oil to maintain good soot dispersion ability and moderate total base number reserve while reducing sulfate ash, phosphorus and sulfur content.

[0031] (ii) This invention combines organic molybdenum friction modifier, organic borate ester friction modifier and polar ester film-forming agent, and synergistically compensates with ashless anti-wear agent under low ZDDP conditions, which can maintain good boundary lubrication and anti-wear performance.

[0032] (III) By controlling the type and dosage window of the rust inhibitor and demulsifier, the present invention enables the obtained oil to still have good oil-water separation performance and rust and corrosion prevention capabilities under water content and storage conditions.

[0033] (iv) This invention does not simply reduce ash and phosphorus and sulfur content, but rather takes into account soot dispersion, friction reduction and wear resistance, demulsification (oil-water separation), rust prevention and corrosion inhibition and after-treatment compatibility under low-SAPS constraints. It is more suitable for non-road compression ignition internal combustion engines equipped with or with exhaust after-treatment devices, and is suitable for forming low-ash lubricating oils with viscosity grades such as SAE 15W-40, 10W-40, 5W-40, 10W-30 and 5W-30. The formulation is preferably designed to meet the performance grade requirements of API CK-4. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] According to one aspect of the present invention, a low-ash off-road compression ignition engine lubricating oil additive mother liquor, based on the total mass of the mother liquor, the mother liquor comprises: 13.0–15.5 wt% of polyisobutylene succinimide type ashless dispersant; The metal cleaning agent is 6.0-8.0 wt%, which is composed of low-sulfur, high-alkalinity, superalkaline magnesium salicylate and low-sulfur, high-alkalinity, superalkaline calcium salicylate. The friction modifier system comprises 4.2–5.0 wt%, wherein the friction modifier system consists of an organomolybdenum friction modifier, an organoborolate friction modifier, and a polar ester film-forming agent; The rust and corrosion inhibitor is 1.1 to 1.5 wt%, which is composed of succinic acid half-ester rust inhibitor and benzotriazole corrosion inhibitor; Modified polyether demulsifier 0.25–0.45 wt%; Zinc- and phosphorus-containing dialkyl dithiophosphate anti-wear agents, 0.50–0.85 wt%; Phosphate ester-based ashless anti-wear agent 0.80–1.10 wt%; Antioxidant 0.90–1.30 wt%, wherein the antioxidant is composed of aromatic amine antioxidants and hindered phenolic antioxidants; And carrier oil, with the balance replenished to 100 wt%.

[0036] This invention provides a low-ash non-road compression ignition engine lubricating oil additive mother liquor. By integrating ashless dispersants, metal detergents, friction modifiers, rust inhibitors, demulsifiers, and other functional additives in a specific ratio into the same mother liquor system, the lubricating oil formulated from this mother liquor still has good soot dispersion ability, moderate total base number reserve, friction reduction and anti-wear performance, oil-water separation performance, and rust and corrosion inhibition ability under the constraints of low sulfate ash, low phosphorus, and low sulfur, and maintains good compatibility with exhaust gas aftertreatment systems.

[0037] It should be noted that the low-ash non-road compression ignition engine lubricant additive mother liquor and the low-ash non-road compression ignition engine lubricant containing the additive mother liquor described in this application are suitable for non-road compression ignition internal combustion engines equipped with or with exhaust aftertreatment devices.

[0038] It should be noted that the main technical concept of this application is: under low-SAPS constraints, by linking and controlling the relative proportions and mother liquor compatibility of the ashless dispersant / metal detergent, the zinc dithiophosphate (ZDDP) / ashless anti-wear agent compensation system, and the rust inhibitor / demulsifier, while taking into account soot dispersion, boundary lubrication, oil-water separation, rust prevention and corrosion inhibition, and post-treatment compatibility.

[0039] Preferably, based on the total mass of the mother liquor, the mother liquor includes: a polyisobutylene succinimide type ashless dispersant, the content of which is 13.0 to 15.5 wt%, for example, it can be 13.0%, 13.5%, 14.0%, 14.5%, 15.0%, 15.5%, or any value between 13.0 and 15.5 wt%. The metal cleaning agent has a content of 6.0 to 8.0 wt%, for example, it can be 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, or any value between 6.0 and 8.0 wt%. The metal cleaning agent is composed of low-sulfur, high-alkalinity, superalkaline magnesium salicylate and low-sulfur, high-alkalinity, superalkaline calcium salicylate. The friction modifier system has a content of 4.2 to 5.0 wt%, for example, it can be 4.2%, 4.4%, 4.6%, 4.8%, 5.0%, or any value between 4.2 and 5.0 wt%. The friction modifier system is composed of an organomolybdenum friction modifier, an organoborolate friction modifier, and a polar ester film-forming agent. The rust and corrosion inhibitor has a content of 1.1 to 1.5 wt%, for example, it can be 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, or any value between 1.1 and 1.5 wt%. The rust and corrosion inhibitor is composed of succinic acid half ester rust inhibitor and benzotriazole corrosion inhibitor. Modified polyether demulsifier, the content of which is 0.25 to 0.45 wt%, for example, can be 0.25%, 0.30%, 0.35%, 0.40%, 0.45%, or any value between 0.25 and 0.45 wt%; The zinc- and phosphorus-containing anti-wear agents, which are zinc dialkyl dithiophosphates, have a content of 0.50 to 0.85 wt%, for example, 0.50%, 0.60%, 0.70%, 0.80%, 0.85%, or any value between 0.50 and 0.85 wt%. Phosphate ester-based ashless anti-wear agents, with a content of 0.80 to 1.10 wt%, for example, can be 0.80%, 0.90%, 1.00%, 1.10%, or any value between 0.80 and 1.10 wt%. The antioxidant has a content of 0.90 to 1.30 wt%, for example, it can be 0.90%, 1.00%, 1.10%, 1.20%, 1.30%, or any value between 0.90 and 1.30 wt%, and the antioxidant is composed of aromatic amine antioxidants and hindered phenolic antioxidants.

[0040] The content of the polyisobutylene succinimide type ashless dispersant is 13.0 to 15.5 wt%, for example, it can be 13.0%, 13.5%, 14.0%, 14.5%, 15.0%, 15.5%, or any value between 13.0 and 15.5 wt%. In a preferred embodiment of the present invention, the metal cleaning agent is composed of low-sulfur, high-alkalinity, superalkaline magnesium salicylate and low-sulfur, high-alkalinity, superalkaline calcium salicylate. Preferably, the low-sulfur, high-alkalinity superalkaline magnesium salicylate and the low-sulfur, high-alkalinity superalkaline calcium salicylate are compounded at a mass ratio of (3.3-3.7):1.

[0041] In a preferred embodiment of the present invention, the friction modifier system simultaneously comprises an organomolybdenum friction modifier, an organoborolate friction modifier, and a polar ester film-forming agent; Preferably, the organic molybdenum friction modifier is dialkyl dithiophosphate molybdenum, the organic borate ester friction modifier is alkyl borate ester, and the polar ester film-forming agent is dialkyl sebacate ester; the mass ratio of the three is 1:(0.95~1.05):(0.80~0.95), and the mass percentages of the three in the mother liquor are 1.45~1.75 wt%, 1.45~1.75 wt%, and 1.25~1.55 wt%, respectively.

[0042] In a preferred embodiment of the present invention, the rust inhibitor is composed of a succinic acid half-ester rust inhibitor and a benzotriazole corrosion inhibitor; Preferably, the mass ratio of the succinic acid half-ester rust inhibitor to the benzotriazole corrosion inhibitor is (3.8-4.2):1; In a preferred embodiment of the present invention, the demulsifier is a modified polyether demulsifier, and its content in the mother liquor is 0.30-0.40 wt%.

[0043] In a preferred embodiment of the present invention, the mother liquor further comprises a zinc- and phosphorus-containing anti-wear agent, an ashless anti-wear agent, an antioxidant, a viscosity index improver, a pour point improver, and an antifoaming agent; wherein the zinc- and phosphorus-containing anti-wear agent is a zinc dialkyl dithiophosphate compound, and its content is 0.60–0.80 wt%; the ashless anti-wear agent is a phosphate ester-based ashless anti-wear agent, and its content is 0.90–1.05 wt%. In a preferred embodiment of the present invention, the antioxidant is a combination of aromatic amine antioxidants and hindered phenolic antioxidants, with a total content of 1.00-1.15 wt%, and the mass ratio of the aromatic amine antioxidant to the hindered phenolic antioxidant is 3:2. In a preferred embodiment of the present invention, the viscosity index improver is a shear stability ethylene-propylene copolymer; In a preferred embodiment of the present invention, the pour point improver is a polymethacrylate pour point improver; In a preferred embodiment of the present invention, the defoamer is a polydimethylsiloxane defoamer.

[0044] Preferably, the mother liquor further comprises a carrier oil, which is preferably a combination of Group III base oil, alkyl naphthalene and synthetic ester, or a combination of PAO synthetic base oil, alkyl naphthalene and synthetic ester.

[0045] According to one aspect of the present invention, the present invention provides a low-ash off-road compression ignition engine lubricating oil suitable for use with or with exhaust aftertreatment devices, the lubricating oil being formulated from the aforementioned low-ash lubricating oil additive mother liquor and base oil, and without the addition of any additional composite additive package for providing detergency, dispersion, anti-wear, anti-oxidation, demulsification or rust prevention functions other than the mother liquor.

[0046] The low-ash off-road compression ignition engine lubricating oil provided by this invention possesses excellent soot dispersion ability and moderate total base number reserve under the constraints of low sulfate ash, low phosphorus, and low sulfur content, effectively inhibiting viscosity growth and deposit formation. It also exhibits excellent demulsification performance, enabling rapid oil-water separation under water-containing conditions, and provides reliable rust and corrosion protection for key components such as cylinder liners, bearings, tappets, and valve mechanisms. Furthermore, under boundary lubrication conditions, it helps reduce the coefficient of friction, improves friction reduction and anti-wear performance, and maintains good compatibility with exhaust gas aftertreatment systems such as DPF and SCR.

[0047] In a preferred embodiment of the present invention, the amount of mother liquor added is 13% to 15% of the mass of the non-road compression ignition internal combustion engine lubricating oil; and the lubricating oil has the following characteristics: sulfate ash content ≤1.0 wt%, phosphorus content ≤0.08 wt%, sulfur content ≤0.4 wt%, total base value 7.5 to 10.5 mgKOH / g, kinematic viscosity at 100℃ 9.3 to 16.3 mm² / s, and high-temperature high-shear viscosity ≥3.5 mPa•s.

[0048] Preferably, the base oil includes one of Group II base oil, or a combination of Group I and Group II base oil, or a combination of Group II and Group III base oil, and the viscosity grade of the lubricating oil is SAE 15W-40, 10W-40, 5W-40, 10W-30 or 5W-30.

[0049] Preferably, the lubricating oil is formulated to meet API CK-4 performance level requirements, and no additional compound additive packages for providing detergency, anti-wear, anti-oxidation, demulsification, or rust prevention functions are added, except for the lubricating oil additive mother liquor.

[0050] According to one aspect of the present invention, a method for preparing the above-mentioned low-ash off-road compression ignition engine lubricating oil is provided, the method comprising: adding the mother liquor to a base oil, mixing uniformly under stirring and shearing conditions to obtain the finished low-ash off-road compression ignition engine lubricating oil.

[0051] In a preferred embodiment of the present invention, the stirring speed is 200-800 r / min and the stirring is carried out at 60-80°C; the shearing is a high-shear homogenization process with a linear velocity of not less than 5 m / s; preferably, the total time for stirring and shearing is 20-40 min.

[0052] It should be further noted that the carrier oil of the mother liquor in this application may be different from the base oil of the finished oil; the former is mainly used to improve the solubility, compatibility and storage stability of the mother liquor system, while the latter is mainly used to meet the target viscosity grade, low temperature fluidity and finished oil usage requirements.

[0053] The technical solution of the present invention will be further described below with reference to the embodiments.

[0054] Examples 1-3 The preparation method of the low-ash non-road compression ignition engine lubricant additive mother liquor NT-50LA includes: Under nitrogen protection, a compound carrier oil, consisting of Group III base oil, alkyl naphthalene, and synthetic ester, was added as a dispersion medium to a 50 L reactor equipped with a stirrer, heating device, and circulating shearing device. The compound carrier oil was prepared by blending these components in a 3:1:1 mass ratio. Subsequently, at 65°C, a shear stability ethylene-propylene copolymer viscosity index improver was first added and allowed to fully dissolve. Then, an ashless dispersant, metal detergent, antioxidant, zinc- and phosphorus-containing anti-wear agent, ashless anti-wear agent, friction modifier system, rust and corrosion inhibitor, demulsifier, pour point improver, and defoamer were added sequentially, with continuous stirring and circulating shearing to ensure a homogeneous system without localized precipitation, resulting in a low-ash non-road compression ignition engine lubricant additive mother liquor.

[0055] The components and dosages of the low-ash lubricating oil additive mother liquor prepared in this embodiment are shown in Tables 1-3.

[0056] Table 1. Composition of the mother liquor for the low-ash non-road compression ignition engine lubricating oil additive in Example 1 of the present invention:

[0057] Table 2. Composition of the mother liquor for the low-ash non-road compression ignition engine lubricating oil additive in Example 2 of the present invention:

[0058] Table 3. Composition of the mother liquor for the low-ash non-road compression ignition engine lubricating oil additive in Example 3 of the present invention:

[0059] It should be noted that the content of each component in Tables 1-3 is based on the total mass of the mother liquor, and the unit is mass percentage (wt%). The values ​​listed in the columns for "Friction Modifier System," "Rust Inhibitor," and "Antioxidant" are the total content of the corresponding compound system in the mother liquor. Each compound system was pre-mixed according to the mass ratios listed in Tables 1-3 before being added to the mother liquor system. Among them: In the friction modifier system, the mass ratio of dialkyl dithiophosphate molybdenum, alkyl borate, and dialkyl sebacate is 1:1:0.875. Based on the total mass of the mother liquor, in Example 1, the three components are 1.60 wt%, 1.60 wt%, and 1.40 wt%, respectively; in Example 2, the three components are 1.46 wt%, 1.46 wt%, and 1.28 wt%, respectively; and in Example 3, the three components are 1.74 wt%, 1.74 wt%, and 1.52 wt%, respectively.

[0060] The mass ratio of succinic acid half-ester rust inhibitor to benzotriazole corrosion inhibitor in the rust and corrosion inhibitor is 4:1; based on the total mass of the mother liquor, the two are 1.04 wt% and 0.26 wt% respectively in Example 1, 0.88 wt% and 0.22 wt% respectively in Example 2, and 1.20 wt% and 0.30 wt% respectively in Example 3.

[0061] The mass ratio of aromatic amine antioxidants to hindered phenolic antioxidants in the antioxidants is 3:2; based on the total mass of the mother liquor, the two are 0.66 wt% and 0.44 wt% respectively in Example 1, 0.54 wt% and 0.36 wt% respectively in Example 2, and 0.78 wt% and 0.52 wt% respectively in Example 3.

[0062] In Tables 1-3, the carrier oil was pre-blended with Group III base oil 4 cSt, alkyl naphthalene AN 23, and synthetic ester BC-108A in a mass ratio of 3:1:1, and the amount added was to make up the total mass of the mother liquor to 100 wt%. After conversion, the total amount of carrier oil in Example 1 was 50.23 wt%, of which Group III base oil 4 cSt, alkyl naphthalene AN 23, and synthetic ester BC-108A were approximately 30.14 wt%, 10.05 wt%, and 10.05 wt%, respectively; the total amount of carrier oil in Example 2 was 54.34 wt%, of which the three components were approximately 32.60 wt%, 10.87 wt%, and 10.87 wt%, respectively; and the total amount of carrier oil in Example 3 was 45.67 wt%, of which the three components were approximately 27.40 wt%, 9.13 wt%, and 9.13 wt%, respectively.

[0063] The raw materials represented by trade names or models in Tables 1-3 are all commercially available raw materials whose sources, trade names / models, and key quality indicators are verified by the supplier's technical data or quality certification documents to ensure that those skilled in the art can obtain and repeat the application.

[0064] Example 4: Low-ash compression ignition internal combustion engine lubricant for API CK-4 applications equipped with or with exhaust aftertreatment devices: Use Group II base oils, or a combination of Group I and Group II base oils, or a combination of Group II and Group III base oils, to formulate a base oil system with a viscosity grade of SAE 15W-40, 10W-40, 5W-40, 10W-30, or 5W-30; this example uses SAE 10W-30 as a representative for illustration.

[0065] The low-ash lubricant additive mother liquor NT-50LA described in Example 1 was added to the base oil at an amount of 14% of the finished oil mass. The mixture was stirred at 400 r / min at 60°C and homogenized by cyclic shear mixing with a shear velocity of not less than 5 m / s for a total processing time of 30 min, ensuring thorough dissolution and dispersion of the additives to obtain a low-ash off-road compression ignition engine lubricant.

[0066] The tested finished oil contained 0.92% sulfate ash, 0.076% phosphorus, 0.31% sulfur, 8.9 mgKOH / g total base, 11.6 mm² / s kinematic viscosity at 100℃, and 3.62 mPa·s high-temperature high-shear viscosity.

[0067] Laboratory simulations of oxidation / deposition, friction and wear, and simulated water-containing conditions have verified that this oil has a low viscosity growth rate after oxidation, good boundary lubrication protection and oil-water separation performance, and good compatibility with DPF (diesel particulate filter) / SCR (selective catalytic reduction) systems.

[0068] Using the same low-ash lubricant additive masterbatch NT-50LA, the formulation is preferably designed to meet the performance requirements of API CK-4. By adjusting the viscosity ratio of the base oil, it can also be formulated into low-ash off-road compression ignition lubricants with viscosity grades of SAE 15W-40, 10W-40, 5W-40, 10W-30 and 5W-30.

[0069] Unless otherwise stated, Comparative Examples 1 to 4 below were all formulated based on the low-ash lubricant additive mother liquor NT-50LA described in Example 4 and the same viscosity grade (SAE 10W-30) base oil system. The amount of finished oil added was 14% in each example. By fine-tuning the ashless dispersant, ashless anti-wear agent and carrier oil, the sulfate ash, phosphorus and sulfur contents of each comparative example were kept on the same order of magnitude as in Example 4.

[0070] Comparative Example 1 Based on Example 4, only the composition of the metal detergent in the low-ash lubricating oil additive mother liquor NT-50LA described in Example 1 was adjusted. The mass ratio of low-sulfur high-alkalinity magnesium-based detergent (super-alkaline magnesium salicylate) to low-sulfur high-alkalinity calcium-based detergent (super-alkaline calcium salicylate) was adjusted to 1:1, while the amount of other components added remained unchanged.

[0071] Laboratory simulations of oxidation / deposition, friction and wear, and simulated water-containing conditions verified that, compared with Example 4, the total base number retention rate of this oil decreased, the viscosity growth rate at 100°C increased, and the oil-water separation time was prolonged. This indicates that under low ash constraints, when the magnesium / calcium ratio deviates from the optimal window, it is difficult to simultaneously achieve detergency and dispersion, base number retention, and demulsification stability.

[0072] Comparative Example 2 Based on Example 4, only the composition of the metal detergent in the low-ash lubricating oil additive mother liquor NT-50LA described in Example 1 was adjusted so that the metal detergent contained only low-sulfur, high-alkalinity magnesium-based detergent (over-alkaline magnesium salicylate). At the same time, the amount of ashless dispersant and carrier oil was finely adjusted so that the sulfate ash, phosphorus, and sulfur content of the finished oil remained at the same order of magnitude as in Example 4.

[0073] Laboratory simulations of oxidation / deposition, friction and wear, and simulated water-bearing conditions have verified that, compared with Example 4, this oil product has decreased in terms of high-temperature detergency, sediment control, and stability under water-bearing conditions, with an increased tendency for sediment formation and a significantly prolonged oil-water separation time.

[0074] Comparative Example 3 Based on Example 4, only the composition of the friction modifier system in the low-ash lubricating oil additive mother liquor NT-50LA described in Example 1 was adjusted. The friction modifier system in this comparative example does not contain organic molybdenum friction modifier (dialkyl dithiophosphate molybdenum), but is replaced by an equal amount of organic borate friction modifier (alkyl borate). That is, the friction modifier system in this comparative example consists of organic borate friction modifier (alkyl borate) and polar ester film-forming agent (dialkyl sebacate). The remaining components and the amount added to the finished oil remain unchanged.

[0075] Friction and wear tests verified that, compared with Example 4, the average friction coefficient of this oil increased and the wear scar diameter increased, indicating that in the low-ash system with reduced ZDDP content, the organic molybdenum friction modifier makes an important contribution to friction reduction and anti-wear performance.

[0076] Comparative Example 4 Based on Example 4, only the composition of the rust inhibitor system in the low-ash lubricating oil additive mother liquor NT-50LA described in Example 1 was adjusted so that the rust inhibitor system consists only of benzotriazole corrosion inhibitors, while the amount of other components added remains unchanged from that of the finished oil.

[0077] The simulated water-containing storage test verified that, compared with Example 4, the oil's rust and corrosion prevention capabilities decreased under water-containing and storage conditions, the oil-water separation time was prolonged, and the emulsion layer volume increased. This indicates that the composite rust and corrosion prevention system is indispensable for the long-term protection of low-ash non-road compression ignition engine lubricating oil.

[0078] Experimental Example 1 To verify the comprehensive performance of the low-ash off-road compression ignition engine lubricating oil provided by the present invention, the finished oil (SAE 10W-30) prepared in Example 4 and the corresponding samples obtained in Comparative Examples 1 to 4 were subjected to physicochemical property tests, oxidation / deposition evaluation, friction and wear evaluation, and simulated water-containing condition tests.

[0079] (1) The test method is as follows: The total base number of new oil was determined according to ASTM D2896; Kinematic viscosity at 100℃ was determined according to GB / T 265-1988; High-temperature high-shear viscosity was determined according to NB / SH / T 0703-2020; (2) The following laboratory simulation evaluation methods were used to characterize the oxidation, deposition, tribology, demulsification and rust prevention performance: The total base number retention rate was determined by accelerated oxidation treatment according to ASTM D7528 (ROBO) and by measuring the total base number before and after oxidation according to ASTM D2896 / ASTM D4739.

[0080] The viscosity growth rate was calculated by measuring the kinematic viscosity at 100°C according to ASTM D445 after accelerated oxidation using ASTM D7528 (ROBO).

[0081] Deposits were assessed using laboratory simulation methods to characterize the deposit formation tendency of samples under high-temperature oxidation, zonal deposition, and thin-film oxidation conditions. The assessment results are used for relative comparisons between the examples and comparative examples and are not equivalent to piston deposit disassembly and inspection scores after a complete engine bench test. Specific evaluation items include: Simulated annular deposition was determined according to ASTM D6335; High-temperature deposition tendency was determined according to ASTM D7097; The oxidative stability of the thin film was determined according to ASTM D4742; Metal corrosion resistance was determined according to ASTM D6594; The average coefficient of friction was determined according to ASTM D5183; The diameter of the four-ball wear scar was determined according to ASTM D4172; Oil-water separation time and emulsion volume were determined according to GB / T 7305-2003 at 54℃ under the conditions of 40 ml-40 ml-0 ml. The corrosion performance was determined according to GB / T 11143-2008 and recorded as 0 to 3 according to the internal rating standard of this application, where 0 indicates no corrosion, 1 indicates slight pitting corrosion, 2 indicates localized flaking corrosion, and 3 indicates obvious corrosion.

[0082] (3) The test results are shown in Tables 4 and 5.

[0083] Table 4. Performance comparison of Example 4 (SAE 10W-30) with Comparative Examples 1-4 (Part 1):

[0084] Table 5. Performance comparison of Example 4 (SAE 10W-30) with Comparative Examples 1-4 (Part 2):

[0085] Note: In Tables 4 and 5, Example 4 is a benchmark low-ash non-road compression ignition engine lubricating oil sample prepared using the additive mother liquor NT-50LA described in Example 1. Comparative Examples 1 to 4 are all based on Example 4 with adjustments made to single factors or main factors, while maintaining basic consistency in the base oil system, finished oil addition amount, preparation process, and low-SAPS constraint indicators such as sulfate ash, phosphorus, and sulfur, to examine the influence of corresponding key components or component ratios on the overall performance of the oil.

[0086] In Comparative Example 1, the mass ratio of magnesium-based detergent to calcium-based detergent in the metal detergent was adjusted from the preferred ratio in Example 4 to 1:1. This was used to investigate the impact of the magnesium / calcium compound ratio deviating from the preferred window on total base number retention, viscosity growth control, deposit control, and oil-water separation performance. Comparative Example 2 was adjusted to contain only magnesium-based detergent. This was used to investigate the impact of the absence of calcium-based detergent on detergent retention, deposit control, and stability under water-containing conditions. Comparative Example 3 removed the organic molybdenum friction modifier from the friction modifier system and replaced it with an organic borate ester friction modifier. This was used to investigate the contribution of the organic molybdenum friction modifier to friction reduction and wear resistance in low ZDDP, low-ash systems. Comparative Example 4 was adjusted to a single-component benzotriazole corrosion inhibitor system. This was used to investigate the effect of the compounding relationship between succinic acid half-ester rust inhibitor and benzotriazole corrosion inhibitor on rust prevention, corrosion inhibition, demulsification, and stability under water-containing conditions.

[0087] Referring to Tables 4 and 5 above, the "Comprehensive Sediment Tendency Score (Internal 10-point scale)" is an internal comprehensive index calculated based on the results of laboratory-simulated sediment evaluation. It is used to compare the sediment control capabilities of Example 4 and each comparative example under the same evaluation conditions. This score comprehensively considers evaluation results such as simulated zonal deposition, high-temperature deposition tendency, and film oxidation stability. The full score is 10 points, with higher scores indicating lower sediment formation tendency and better sediment control performance. This score is not a direct test value from a single standard method, nor is it equivalent to the piston sediment disassembly and inspection score after a complete engine bench test.

[0088] The "Rust Rating" is an internal record of 0 to 3 levels based on the rust condition of the test specimens after the GB / T 11143-2008 test, where 0 indicates no rust, 1 indicates slight pitting rust, 2 indicates localized flaky rust, and 3 indicates significant rust. This rating is used for relative comparison between the examples and comparative examples. In Table 2, "higher is better" or "lower is better" only indicates the preferred performance direction for the corresponding indicator and does not represent API CK-4 certification limits or the standard for passing full engine bench certification.

[0089] The sulfate ash content, phosphorus content, sulfur content, total base number of new oil, kinematic viscosity at 100°C, and high-temperature high-shear viscosity of Examples 4 and Comparative Examples 1-4 are all at similar levels, indicating that the performance comparison of each sample is based on the same low-SAPS constraints and the same viscosity grade. Therefore, the differences in total base number retention rate, viscosity growth rate, sedimentation tendency comprehensive score, friction and wear, oil-water separation, emulsion volume, and corrosion rating in Table 2 mainly reflect the impact of changes in the corresponding key components or component ratios.

[0090] Compared with Comparative Example 1, Example 4, using a preferred magnesium / calcium detergent blend ratio, showed an increase in total base number retention from 60% to 68%, a decrease in viscosity growth rate at 100°C from 29% to 21%, an increase in the overall sedimentation tendency score from 7.9 to 8.6, a reduction in oil-water separation time from 21 min to 14 min, and a decrease in emulsion volume from 4.2 mL to 2.0 mL. These results indicate that under low-SAPS constraints, magnesium-based and calcium-based detergents are not simply equivalent substitutes; the preferred blend ratio specified in this application is more advantageous in balancing base number retention, viscosity growth control, sedimentation control, and oil-water separation performance.

[0091] Compared to Comparative Example 2, Example 4, by simultaneously using a magnesium-based detergent and a calcium-based detergent in the metal detergent, saw an increase in total base number retention from 58% to 68%, a rise in the overall deposit tendency score from 7.5 to 8.6, a reduction in oil-water separation time from 28 min to 14 min, a decrease in emulsion volume from 6.8 mL to 2.0 mL, and an improvement in the rust rating from level 2 to level 0. These results indicate that while using only a magnesium-based detergent can maintain a certain base number reserve, it is difficult to simultaneously achieve deposit control, demulsification stability, and rust prevention under water-bearing conditions in a low-ash system. The combination of calcium-based and magnesium-based detergents has a positive effect on improving overall balance.

[0092] Compared to Comparative Example 3, Example 4, by retaining the organic molybdenum friction modifier in the friction modifier system, saw a decrease in the average coefficient of friction from 0.109 to 0.083, and a decrease in the diameter of the four-ball wear scar from 0.53 mm to 0.40 mm. Meanwhile, the sulfate ash content, phosphorus content, sulfur content, total base number, and oil-water separation performance remained similar in both examples. These results indicate that in low-ash systems where ZDDP dosage is limited, the combination of organic molybdenum friction modifiers with organic borate ester friction modifiers and polar ester film-forming agents helps improve boundary lubrication and anti-wear protection without significantly increasing ash, phosphorus, and sulfur loads.

[0093] Compared to Comparative Example 4, Example 4, using a composite rust and corrosion inhibitor system composed of succinic acid half-ester rust inhibitor and benzotriazole corrosion inhibitor, reduced the oil-water separation time from 33 min to 14 min, decreased the emulsion volume from 9.2 mL to 2.0 mL, and improved the rust rating from level 3 to level 0. Meanwhile, the friction coefficient, wear scar diameter, and total base number retention rates of the two systems showed little difference. These results indicate that the main performance shortcomings of Comparative Example 4 are concentrated in oil-water separation and rust and corrosion inhibition under water-containing conditions. This suggests that using benzotriazole corrosion inhibitors alone is insufficient to meet the protection requirements of the low-ash non-road compression-ignition internal combustion engine lubricating oil in this application under high humidity, water-containing, and intermittent parking conditions. The combination of succinic acid half-ester rust inhibitor and benzotriazole corrosion inhibitor is more conducive to achieving a balance between demulsification and rust and corrosion inhibition performance.

[0094] In summary, Tables 4 and 5 not only demonstrate that the individual performance of Example 4 is superior to that of the comparative example, but also further prove that in the low-SAPS system where sulfate ash, phosphorus, and sulfur are all limited, the magnesium / calcium compound ratio of the metal detergent, the composite friction modifier system containing organic molybdenum, and the composite rust and corrosion inhibitor system of succinic acid half-ester rust inhibitor / benzotriazole corrosion inhibitor respectively contribute to the maintenance of alkalinity and deposit control, friction reduction and wear resistance, oil-water separation, and rust and corrosion prevention. The combined effect of the above systems enables Example 4 to achieve a comprehensive balance of detergent retention, friction reduction and wear resistance, demulsification, rust prevention, and post-treatment compatibility under low ash constraints.

[0095] Therefore, this invention does not simply reduce ash and phosphorus and sulfur content, but rather achieves a comprehensive balance of soot dispersion, friction reduction and wear resistance, oil-water separation, rust prevention and protection, and post-treatment compatibility by linking and controlling the structure of the metal detergent, the friction modifier system, and the rust prevention and corrosion inhibition / demulsification system under low-SAPS constraints.

[0096] In summary, the low-ash lubricant additive mother liquor NT-50LA provided by this invention can, under the constraints of low sulfate ash, low phosphorus, and low sulfur, simultaneously achieve soot dispersion, moderate total base number reserve, friction reduction and wear resistance, oil-water separation, rust and corrosion prevention, and after-treatment compatibility. The low-ash off-road compression ignition engine lubricant formulated using this mother liquor is suitable for mainstream applications equipped with or pre-installed with exhaust after-treatment devices, and maintains good comprehensive protective performance even under low ZDDP conditions. Therefore, in addition to its good technical consistency and application value, it also has significant technological advancement significance and broad industrialization prospects.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low-ash non-road compression ignition engine lubricating oil additive mother liquor, characterized in that, Based on the total mass of the mother liquor, the mother liquor comprises: 13.0–15.5 wt% of polyisobutylene succinimide type ashless dispersant; The metal cleaning agent is 6.0-8.0 wt%, which is composed of low-sulfur, high-alkalinity, superalkaline magnesium salicylate and low-sulfur, high-alkalinity, superalkaline calcium salicylate. The friction modifier system comprises 4.2–5.0 wt%, wherein the friction modifier system consists of an organomolybdenum friction modifier, an organoborolate friction modifier, and a polar ester film-forming agent; The rust and corrosion inhibitor is 1.1 to 1.5 wt%, which is composed of succinic acid half-ester rust inhibitor and benzotriazole corrosion inhibitor; Modified polyether demulsifier 0.25–0.45 wt%; Zinc- and phosphorus-containing dialkyl dithiophosphate anti-wear agents, 0.50–0.85 wt%; Phosphate ester-based ashless anti-wear agent 0.80–1.10 wt%; Antioxidant 0.90–1.30 wt%, wherein the antioxidant is composed of aromatic amine antioxidants and hindered phenolic antioxidants; And carrier oil, with the balance replenished to 100 wt%.

2. The additive mother liquor according to claim 1, characterized in that, The mass ratio of the ashless dispersant to the metal detergent is (1.9-2.3):

1.

3. The additive mother liquor according to claim 1 or 2, characterized in that, The mass ratio of the low-sulfur, high-alkalinity superalkaline magnesium salicylate to the low-sulfur, high-alkalinity superalkaline calcium salicylate is (3.3-3.7):1, preferably 3.5:

1.

4. The additive mother liquor according to claim 1 or 2, characterized in that, The organic molybdenum friction modifier in the friction modifier system is dialkyl dithiophosphate molybdenum; The organoboroester friction modifier is an alkylboronate; The polar ester film-forming agent is a dialkyl sebacate; And / or, the mass ratio of the organomolybdenum friction modifier, organoborolate friction modifier and polar ester film-forming agent in the friction modifier system is 1:(0.95-1.05):(0.80-0.95).

5. The additive mother liquor according to claim 1, characterized in that, The mass ratio of succinic acid half-ester rust inhibitor to benzotriazole corrosion inhibitor in the rust inhibitor is (3.8-4.2):1, and the content of the modified polyether demulsifier is 0.30-0.40 wt%.

6. The additive mother liquor according to claim 1, characterized in that, The content of the zinc- and phosphorus-containing dialkyl dithiophosphate zinc anti-wear agent is 0.60–0.80 wt%; The content of the phosphate ester-based ashless anti-wear agent is 0.90–1.05 wt%; The antioxidant content is 1.00-1.15 wt%, and the mass ratio of the aromatic amine antioxidant to the hindered phenolic antioxidant is 3:

2.

7. The additive mother liquor according to claim 1, characterized in that, The mother liquor further comprises 18.5–20.0 wt% of an ethylene-propylene copolymer viscosity index improver, 0.40–0.60 wt% of a polymethyl methacrylate pour point improver, and 0.01–0.03 wt% of a polydimethylsiloxane defoamer, and the carrier oil comprises any combination of the following: (a) A combination of Group III base oils, alkyl naphthalenes, and synthetic esters; (b) A combination of PAO synthetic base oil, alkyl naphthalene and synthetic ester.

8. A low-ash off-road compression ignition engine lubricating oil, characterized in that, The lubricating oil includes a base oil and a lubricating oil additive mother liquor according to any one of claims 1 to 7; The amount of mother liquor added is 13% to 15% of the total mass of the lubricating oil, and the lubricating oil has the following characteristics: sulfate ash content ≤1.0 wt%, phosphorus content ≤0.08 wt%, sulfur content ≤0.4 wt%, total base value 7.5 to 10.5 mgKOH / g, kinematic viscosity at 100℃ 9.3 to 16.3 mm² / s, and high-temperature high-shear viscosity ≥3.5 mPa·s.

9. The low-ash off-road compression ignition engine lubricating oil according to claim 8, characterized in that, The base oil includes Group II base oil, or a combination of Group I and Group II base oil, or a combination of Group II and Group III base oil, and the viscosity grade of the lubricating oil is SAE 15W-40, 10W-40, 5W-40, 10W-30 or 5W-30.

10. A method for preparing a low-ash off-road compression ignition engine lubricating oil according to claim 8 or 9, characterized in that, The preparation method includes: The lubricating oil additive mother liquor is added to the base oil at a dosage of 13% to 15% of the total mass of the lubricating oil, stirred at 200 to 800 r / min at 60 to 80°C, and subjected to shear homogenization treatment for 20 to 40 min to obtain the lubricating oil.

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