Method for testing lubricating performance of M100 methanol fuel

Abstract

The invention discloses a method for testing lubricating performance of M100 methanol fuel, which comprises the following steps of: clamping three steel balls with the diameter of 12.7 mm in an oil box, immersing the steel balls in test oil, placing another steel ball with the same diameter at the top of the three balls, applying specified load, and forming three-point contact with three lower steel balls in the oil box under the action of test force, so as to test the lubricating performance of the M100 methanol fuel. When the test oil reaches the specified test temperature, the top ball rotates for a certain time according to the specified rotating speed, and after the test is finished, the wear scar diameters of the three lower steel balls are measured to evaluate the lubricating performance of the oil product. The method has the characteristics of simplicity in operation and high detection speed, the repeatability and discrimination of the detection result are excellent, the lubricating performance of the M100 methanol fuel and the lubricating performance of the M100 methanol fuel added with the lubricating additive can be effectively distinguished, and the test correlation is high.

Description

Technical Field

[0001] The invention relates to a method for testing the lubricity of M100 methanol fuel. Background Art

[0002] Engine fuel must not only have good combustion performance, but also have a certain lubricity to prevent serious wear and failure of the oil pump, fuel control system and nozzle in the fuel supply system. As for gasoline, due to the relatively mild lubrication conditions and insufficient refining depth, although there were signs of gasoline wear in the mid-1990s, large-scale oil pump failures have not yet occurred. In recent years, due to the strict restrictions on the components and production processes of gasoline by new emission regulations, the effective lubricating components in gasoline have been greatly reduced, thereby affecting the lubricity of gasoline and causing increased wear between fuel pump parts. Methanol has a lower viscosity and its lubricity is milder than gasoline, and the wear on the fuel pump is more obvious. The inventor has conducted relevant research on the lubricity of M100 methanol fuel.

[0003] The existing methods for measuring lubrication performance mainly include the four-ball friction and wear tester method and the high-frequency reciprocating tester method. Among them, the four-ball friction and wear tester method is easy to operate, low in cost and reliable in measurement results, and is the most commonly used lubricity evaluation method in laboratories. Summary of the invention

[0004] The invention provides a method for testing the lubricity of M100 methanol fuel, so as to provide an effective means for evaluating the lubricity of M100 methanol fuel.

[0005] To achieve the above object, the present invention provides the following technical solution: a method for testing the lubricity of M100 methanol fuel, comprising the following steps in sequence:

[0006] S1: First use solvent oil, then use petroleum ether to carefully clean the four test balls, the ball clamp, the oil box and all parts in contact with the test oil, and wipe them with wiping supplies;

[0007] S2: Clamp the three cleaned test balls in an oil box and immerse them in the test oil. Place another steel ball of the same diameter on top of the three balls.

[0008] S3: Place the oil box on the oil box seat and slowly apply the test load to the load required by the test conditions;

[0009] S4: Heat the test oil to the test temperature ±2°C, start the motor, make the spindle speed reach the speed specified by the set test conditions, and start the test timing;

[0010] S5: After the test time is reached, stop heating and turn off the motor, remove the load, take out the oil box, and pour out the test oil;

[0011] S6: The lubrication performance of the oil is evaluated by measuring the wear spot diameters of the three lower steel balls using a measuring tool.

[0012] The test conditions for measuring the lubricity of M100 methanol fuel using the four-ball friction and wear tester method are as follows: test oil temperature: 30°C; rotation speed: 1200 rpm; load: 130-150 N; time: 10-20 min.

[0013] Three steel balls with a diameter of 12.7mm are clamped in an oil box and immersed in the test oil. Another steel ball with the same diameter is placed on the top of the three balls and a specified load is applied. Under the action of the test force, a "three-point contact" is formed with the three lower steel balls in the oil box. When the test oil reaches the specified test temperature, the top ball rotates at the specified speed for a certain period of time. After the test, the wear spot diameters of the three lower steel balls are measured to evaluate the lubrication performance of the oil.

[0014] Preferably, the test conditions for measuring the lubricity of M100 methanol fuel using a four-ball friction and wear tester method are: test oil temperature: 30° C.; rotation speed: 1200 rpm; load: 140 N; time: 15 min.

[0015] Preferably, the measuring tool is a microscope, and the resolution of the microscope is 0.01 mm.

[0016] Preferably, the wiping article can be a clean silk cloth or an unused absorbent cotton ball.

[0017] Preferably, the test ball is a steel ball with a diameter of 12.7 mm.

[0018] Beneficial effects of the present invention:

[0019] The method for measuring the lubricity of M100 methanol fuel by using a four-ball friction and wear tester provided by the present invention has the characteristics of simple operation and fast detection speed, excellent repeatability and differentiation of detection results, and can effectively distinguish the lubricity of M100 methanol fuel and M100 methanol fuel with added lubricity additives, and has high test correlation. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The test instruments, materials, reagents, test procedures, precision and result calculation used in this invention are all based on NB / SH / T 0189-2017.

[0022] The investigation and determination of the test parameters are described as follows.

[0023] 1. Test equipment and materials

[0024] Four-ball wear tester; microscope: resolution 0.01mm; steel ball: in accordance with GB / T 308.1; petroleum ether: in accordance with GB / T 15894; solvent oil: in accordance with GB1922

[0025] 2. Test steps

[0026] S1: First use solvent oil, then use petroleum ether to carefully clean the four test balls, the ball clamp, the oil box and all parts that come into contact with the test oil. Finally, the test steel balls can be wiped with a clean silk cloth or unused absorbent cotton balls. Do not touch the washed steel balls with your hands, and there should be no solvent residue on the steel balls.

[0027] S2: Install a clean steel ball in the fixture at the lower end of the spindle, install three clean steel balls in the oil box, and tighten. Pour the test oil into the oil box. Since M100 methanol fuel is easy to volatilize, in order to ensure that the steel ball is always immersed in the test oil during the entire experiment, the test oil is required to exceed the top of the steel ball by at least 5mm. And observe the test oil level at intervals, and replenish the test oil in time to ensure that it meets the requirements.

[0028] S3: Place the oil box on the oil box seat and slowly apply the test load to the load required by the test conditions, avoiding impact.

[0029] S4: Heat the test oil to the test temperature ±2°C, start the motor, make the spindle speed reach the speed specified by the set test conditions, and start the test timing.

[0030] S5: When the test time is reached, stop heating and turn off the motor, remove the load, take out the oil box, and pour out the test oil.

[0031] S6: Use a microscope to measure the diameter of the wear spots on the three lower steel balls in the oil box with a measurement accuracy of 0.01mm. Measure the wear spot on each ball twice, once along the center line of the oil box and the other time perpendicular to the first time. Report the arithmetic mean of the wear spot diameters of the three steel balls measured six times in millimeters. If the wear spot is an ellipse, make one measurement along the direction of the wear spot and another measurement perpendicular to the direction of the wear spot. If the average of the two measurements of a lower steel ball deviates from the average of all six measurements by more than 0.04mm, the axial alignment of the upper ball and the oil cup should be checked. Finally, record the average value of the wear spot diameter to evaluate the lubrication performance of M100 methanol fuel.

[0032] 3. Determination of test conditions

[0033] 1. Test temperature

[0034] The test temperature will affect the kinematic viscosity of M100 methanol, and thus its lubrication performance. When the temperature is too low, the viscosity increases, and it is not easy to flow to the friction surface, causing wear of the machine parts; when the temperature is high, the viscosity decreases, and it is not easy to form an oil film of appropriate thickness on the friction surface, which loses the lubrication effect and easily causes scratches on the friction surface. Since M100 methanol fuel is very volatile at high temperatures, it not only affects the test results, but also methanol has a certain toxicity, which will harm the test personnel. Therefore, in order to ensure that the oil film thickness between the friction pairs is appropriate during the entire experiment and the test results are reliable and effective, the oil sample temperature is set to 30°C during the test.

[0035] 2. Spindle speed

[0036] The spindle speed is an important parameter in the test process. The influence of the speed is mainly due to the heat and temperature changes caused by it. If the speed is too high, friction will generate heat, methanol volatilization will be accelerated, and the lubrication between the friction surfaces will be affected; if the speed is too low, the friction frequency of the friction pair will be low and the wear spots will not be obvious. In order to reduce the influence of the speed on the test and ensure the lubrication conditions between the friction surfaces, the speed is set to 1200rpm.

[0037] 3. Test load and time

[0038] The load should remain stable during the test. If the load is too high, the friction pair will bite and the wear will increase sharply. If the load is too low, the wear phenomenon is not obvious and the test data cannot be read.

[0039] The test time also has a certain impact on the results. If the test time is too long, the methanol temperature will rise and evaporate, affecting the oil film thickness between the friction pairs. If the test time is too short, the wear spot will be too small and difficult to observe or measure.

[0040] A selective test on test time and load was conducted for M100 methanol fuel. The test oil temperature was 30°C, the spindle speed was 1200 rpm, the time and load were set according to the data in the table (time unit is min, load unit is N), and the wear spot diameter unit is millimeter (mm). The results are shown in Table 1.

[0041] Table 1 Test load and time results

[0042]

[0043] From the results shown in Table 1, it can be seen that for M100 methanol fuel, the lubricity test can be carried out within the test time range of 10 to 20 minutes and the load range of 120 to 150 N.

[0044] Based on the above experiments, the inventors conducted a selection experiment of specific parameters of test time and load:

[0045] The test oil was M100 methanol fuel, the test temperature was 30°C, the spindle speed was 1200 rpm, and the test plan and results are shown in Tables 2 and 3.

[0046] Table 2 Test results at different test times

[0047]

[0048] Table 3 Test results of different test loads

[0049]

[0050] From the results in Table 2, it can be seen that the wear spot diameter increases with the increase of test time. After 14 minutes, the wear spot diameter increases rapidly. In the final stage of the test, the friction condition deteriorates and micro-seizure occurs.

[0051] From the results shown in Table 3, it can be seen that the wear spot diameter increases with the increase of the test load, and when the load exceeds 160N, the biting phenomenon occurs.

[0052] Based on the above test analysis results, if the wear spot diameter is too small, the wear spot is not obvious and difficult to observe, and finding the wear spot is time-consuming and laborious; when the wear spot is too large, the friction pairs are very easy to bite. In order to improve the test efficiency, the test time is determined to be 15 minutes and the test load is 140N.

[0053] Example 1

[0054] The test instruments, materials, methods and result measurement methods of this embodiment refer to NB / SH / T0189-2017. The test oil is M100 methanol fuel, the test temperature is 30°C, the spindle speed is 1200rpm, the time is 15min, and the load is 140N. A total of 5 repeated tests were carried out, and the test results are shown in Table 4.

[0055] Table 4 Experimental results of Example 1

[0056] frequency 1 2 3 4 5 Wear spot diameter / mm 0.37 0.40 0.42 0.38 0.39

[0057] The results shown in Table 4 show that the average value of 5 repeated test results is 0.376 mm, and the maximum difference between two results is 0.05 mm. The test results have good repeatability.

[0058] Example 2

[0059] The test oil of this embodiment is M100 methanol fuel, the test temperature is 30°C, the spindle speed is 1200 rpm, the time is 10 min, and the load is 150 N. A total of 5 repeated tests are carried out, and the test results are shown in Table 5.

[0060] Table 5 Experimental results of Example 2

[0061] frequency 1 2 3 4 5 Wear spot diameter / mm 0.45 0.48 0.44 0.43 0.46

[0062] Example 3

[0063] The test oil of this embodiment is M100 methanol fuel, the test temperature is 30°C, the spindle speed is 1200 rpm, the time is 20 min, and the load is 130 N. A total of 5 repeated tests are carried out, and the test results are shown in Table 6.

[0064] Table 6 Experimental results of Example 3

[0065] frequency 1 2 3 4 5 Wear spot diameter / mm 0.37 0.41 0.42 0.39 0.39

[0066] Example 4

[0067] Since the lubrication performance of M100 methanol fuel is poor, an effective anti-wear component needs to be added when used in vehicles. Two M100 methanol fuels containing anti-wear agents were tested 5 times, and the basic M100 methanol fuel was the same as in Example 1. Test temperature: 30°C, spindle speed: 1200rpm, time: 15min, load: 140N, a total of 5 repeated tests were carried out, and the test results are shown in Table 7.

[0068] Table 7 Experimental results of Example 4

[0069]

[0070] The average value of the results of 5 repeated tests shown in Table 7 is 0.32 mm, while the average value of the test results of M100 methanol fuel without anti-wear agent is 0.376. The difference is obvious, and this method has good discrimination.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for testing the lubricity of M100 methanol fuel, characterized in that: The following steps are included in sequence: S1: First use solvent oil, then use petroleum ether to carefully clean the four test balls, the ball clamp, the oil box and all parts in contact with the test oil, and wipe them with wiping supplies; S2: Clamp the three cleaned test balls in an oil box and immerse them in the test oil. Place another steel ball of the same diameter on top of the three balls. S3: Place the oil box on the oil box seat and slowly apply the test load to the load required by the test conditions; S4: Heat the test oil to the test temperature ±2°C, start the motor, make the spindle speed reach the speed specified by the set test conditions, and start the test timing; S5: After the test time is reached, stop heating and turn off the motor, remove the load, take out the oil box, and pour out the test oil; S6: The lubrication performance of the oil is evaluated by measuring the wear spot diameters of the three lower steel balls using a measuring tool; The test conditions for measuring the lubricity of M100 methanol fuel using the four-ball friction and wear tester method are as follows: test oil temperature: 30°C; rotation speed: 1200 rpm; load: 130-150 N; time: 10-20 min.

2. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The test oil temperature was 30°C.

3. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The rotation speed is 1200 rpm.

4. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The applied load is 140N.

5. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The load application time is 15 minutes.

6. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The measuring tool is a microscope, and the resolution of the microscope is 0.01 mm.

7. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The wiping article can be made of clean silk cloth or unused absorbent cotton balls.

8. A method for testing lubricity of M100 methanol fuel according to claim 1, characterized in that: The test ball is a steel ball with a diameter of 12.7 mm.

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