Methanol engine lubricating oil matching evaluation method

Abstract

The invention discloses a methanol engine lubricating oil matching evaluation method and belongs to the technical field of engine detection. The method comprises the following steps: taking an A group and a B group of same engine parts; preparing a lubricating oil mixed solution containing a compound as a simulated pollutant; performing a soaking test on the group A engine parts by using the simulated pollutants; carrying out physical and chemical property detection on the soaked group A engine parts and formulating an acceptance criterion; selecting the same engine parts from the group B of engine parts for the group A of engine parts meeting the acceptance criterion, and then mounting the selected engine parts on the methanol engine; carrying out a complete machine rack endurance test on the methanol engine and collecting a lubricating oil sample after the test; and detecting the contents of copper element, water, methanol and formic acid in the lubricating oil sample, and formulating acceptance criteria. According to the method, the design failure prevention period is advanced, the fault probability of abrasion, corrosion and leakage of the engine is reduced, and quantitative evaluation of the emulsification tendency of the lubricating oil, the additive stability and the corrosion resistance of parts is achieved.

Description

Technical Field

[0001] The invention relates to a method for evaluating the matching performance of a methanol engine lubricating oil, and belongs to the technical field of engine detection. Background Art

[0002] Traditional gasoline engine lubricant inspection or assessment methods primarily focus on used oil samples obtained during bench durability testing, with test indicators including pH, metal content (such as iron and aluminum), and viscosity. However, in methanol-fueled engines, methanol combustion produces acidic substances such as formic acid and intermediates, and the combustion produces far more water than gasoline, which can easily lead to oil emulsification. These substances, when dissolved in the lubricant, alter its composition and exacerbate damage to engine hardware, such as metal corrosion, friction pair wear, coating shedding, and rubber component degeneration and failure.

[0003] Because traditional methods do not include components such as methanol and formic acid that seriously affect lubricant performance and corrode engine hardware into the assessment indicators, it is impossible to evaluate the lubricant's tolerance to the specific pollutants of methanol engines.

[0004] In addition, traditional testing relies heavily on whole-machine bench durability testing and does not conduct individual performance assessments of engine parts (such as sealing rings, rubber parts, and metal parts). This makes it difficult to discover compatibility issues between materials and contaminated lubricants in advance during the development stage, resulting in loopholes in the development process and possible design failures. Summary of the Invention

[0005] In order to solve the problems existing in the background technology, the present invention provides a method for evaluating the compatibility of methanol engine lubricating oil.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for evaluating the compatibility of a methanol engine lubricating oil, the method comprising the following steps:

[0007] S1: Take two sets of identical engine parts and define them as Group A and Group B respectively;

[0008] S2: preparing a mixed solution of lubricating oil containing compounds as simulated pollutants;

[0009] The compound S2 is one of the following four compounds: 5% methanol, 10% methanol, 100% methanol, or a mixture of 12 PPM formate ions and 1.5% methanol.

[0010] S3: Immerse Group A engine parts in simulated contaminants;

[0011] The conditions of the immersion test in S3 are: temperature of 80°C ± 5°C, time of 72h ± 2h, keeping the solution sealed during the immersion process and not applying external force.

[0012] S4: Perform physical and chemical performance tests on all engine parts in Group A after immersion and establish acceptance criteria;

[0013] The physical and chemical property testing described in S4 includes but is not limited to one or more of a tensile test, a hardness test, and a volume change rate test.

[0014] The acceptance criteria in S4 are set based on the rate of change of the physical and chemical properties of the parts before and after immersion. When the rate of change exceeds a predetermined threshold, it is determined to be mismatched.

[0015] S5: For Group A engine parts that meet the acceptance criteria, select the same engine parts from Group B engine parts and install them on the methanol engine;

[0016] S6: Conduct a bench endurance test on the methanol engine and collect lubricating oil samples after the test;

[0017] S7: Test the lubricating oil samples for copper, water, methanol, and formic acid and establish acceptance criteria.

[0018] The detection of the lubricating oil sample in S7 also includes the detection of the composition and content of the viscosity index improver.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] By constructing a simulated pollutant system containing methanol and formate ions, the present invention for the first time incorporates the impact of methanol fuel combustion characteristics on lubricant performance and engine hardware into the scope of quantitative assessment, solving the technical problem that traditional detection methods lack evaluation of the special corrosion mechanism of methanol engines; through the dual verification mechanism of parts single immersion test and bench durability test, the compatibility risk of materials and contaminated lubricants can be identified in advance during the development stage, and the failure prevention cycle can be designed in advance, significantly reducing the probability of engine wear, corrosion and leakage failures; by formulating acceptance criteria covering key indicators such as metal corrosion, rubber swelling, and viscosity attenuation, a quantitative evaluation of lubricant emulsification tendency, additive stability and parts corrosion resistance is achieved, while reducing development costs, establishing a matching evaluation standard system for methanol engine-specific lubricants, and providing a scientific verification method for the development of fuel-adaptive engines. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of a rubber part cutting specimen;

[0022] Figure 2 It is a schematic diagram of the rubber tensile test;

[0023] Figure 3 Schematic diagram of preparing a lubricating oil mixed solution containing methanol and formate ion compounds;

[0024] Figure 4 It is a schematic diagram of the rubber part immersion test. DETAILED DESCRIPTION

[0025] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] A method for evaluating the compatibility of a methanol engine lubricant, comprising the following steps:

[0027] S1: Take two sets of identical engine parts and define them as Group A and Group B respectively;

[0028] S2: preparing a mixed solution of lubricating oil containing compounds as simulated pollutants;

[0029] The compound S2 is one of the following four compounds: 5% methanol, 10% methanol, 100% methanol, or a mixture of 12 PPM formate ions and 1.5% methanol.

[0030] S3: Immerse Group A engine parts in simulated contaminants;

[0031] The conditions of the immersion test in S3 are: temperature of 80°C ± 5°C, time of 72h ± 2h, keeping the solution sealed during the immersion process and not applying external force.

[0032] S4: Perform physical and chemical performance tests on all engine parts in Group A after immersion and establish acceptance criteria;

[0033] The physical and chemical performance testing described in S4 includes but is not limited to one or more of a tensile test, a hardness test, and a volume change rate test, and is used to comprehensively evaluate the performance changes of engine parts after immersion.

[0034] The acceptance criteria in S4 are set based on the rate of change of the physical and chemical properties of the parts before and after immersion. When the rate of change exceeds a predetermined threshold, it is determined to be mismatched.

[0035] S5: For Group A engine parts that meet the acceptance criteria, select the same engine parts from Group B engine parts and install them on the methanol engine;

[0036] S6: Conduct a bench endurance test on the methanol engine and collect lubricating oil samples after the test;

[0037] S7: Test the lubricating oil samples for copper, water, methanol, and formic acid and establish acceptance criteria.

[0038] The detection of the lubricating oil sample in S7 also includes the detection of the composition and content of the viscosity index improver, and the preset threshold value thereof is determined according to the operating conditions of the methanol engine.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0040] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for evaluating the compatibility of a methanol engine lubricant, characterized by: The method comprises the following steps: S1: Take two sets of identical engine parts and define them as Group A and Group B respectively; S2: preparing a mixed solution of lubricating oil containing compounds as simulated pollutants; S3: Immerse Group A engine parts in simulated contaminants; S4: Perform physical and chemical performance tests on all engine parts in Group A after immersion and establish acceptance criteria; S5: For Group A engine parts that meet the acceptance criteria, select the same engine parts from Group B engine parts and install them on the methanol engine; S6: Conduct a bench endurance test on the methanol engine and collect lubricating oil samples after the test; S7: Test the lubricating oil samples for copper, water, methanol, and formic acid and establish acceptance criteria.

2. The method for evaluating the compatibility of a methanol engine lubricating oil according to claim 1, wherein: The compound S2 is one of the following four compounds: 5% methanol, 10% methanol, 100% methanol, or a mixture of 12 PPM formate ions and 1.5% methanol.

3. The method for evaluating the compatibility of a methanol engine lubricating oil according to claim 1, wherein: The conditions of the immersion test in S3 are: temperature of 80°C ± 5°C, time of 72h ± 2h, keeping the solution sealed during the immersion process and not applying external force.

4. The method for evaluating the compatibility of a methanol engine lubricating oil according to claim 3, wherein: The physical and chemical property testing described in S4 includes but is not limited to one or more of a tensile test, a hardness test, and a volume change rate test.

5. The method for evaluating the compatibility of a methanol engine lubricating oil according to claim 4, wherein: The acceptance criteria in S4 are set based on the rate of change of the physical and chemical properties of the parts before and after immersion. When the rate of change exceeds a predetermined threshold, it is determined to be mismatched.

6. A methanol engine lubricant oil compatibility evaluation method according to claim 1 or 5, characterized in that: The detection of the lubricating oil sample in S7 also includes the detection of the composition and content of the viscosity index improver.

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