SH/T 0645-1997 Determination of detergency of diesel engine oils (heat tube oxidation method)

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Card type: Test method

1. Method number / full name / English name / replacement relationship

• Standard number: SH/T 0645-1997
• Chinese name: Determination of detergency of diesel engine oils (heat tube oxidation method)
• English name (original text layer, source-text extraction has much noise): Lubricant test method for determination of detergence of diesel engine — Hot tube method (requires confirmation against the source standard (source-text extraction))
• Replacement relationship: not provided in the available source

2. Scope of application and non-applicability

• This standard specifies a test method for simulated evaluation of the detergency of diesel engine oils.
• It is applicable to simulated evaluation of the detergency of diesel engine oils.
• It specifies the equipment, gas flow rate, sample flow rate, reaction conditions, and rating of levels for simulated evaluation of the detergency of diesel engine oils.
• It proposes the test temperature and time for simulated evaluation of the detergency of CC and CD grade diesel engine oils.
• It is not applicable to simulated evaluation of the detergency of lubricating oils in which the phenolic additive content in diesel engine oil is greater than 2%.

3. Method principle

The test sample (diesel engine oil), after being mixed with oxygen in a controlled high-temperature oxidizing environment, circulates and refluxes in a glass tube subjected to high temperature. After the set temperature and time, deposits will form on the inner wall of the heated glass tube. The shade of color and amount of the deposits have a certain correlation with the detergency of the sample. On this basis, the detergency of diesel engine oils is evaluated by simulation.

4. Reagents and materials (purity / preparation)

• 5.6 Ethanol: 95%, chemically pure.
• 5.7 n-Heptane: chemically pure.
• 5.8 Distilled water: meets grade three of the GB/T 6682 laboratory water specifications.
• 5.10 Standard color tubes: composed of 11 reaction tubes of different deposit levels, with a period of validity of three years; for the level standards, see Appendix A (appendix to the standard).
• 5.11 Standard test oils: composed of six kinds of oil products; uniformly prepared and provided by the Petrochemical Research Institute of Lanzhou Refining and Chemical General Factory according to the standard requirements; for the levels, see Appendix B (appendix to the standard).
• 5.13 Aviation washing gasoline: meets SH 0114.
• 5.14 Oxygen purity 98% or above.
• 5.15 Absorbent cotton.
• 5.17 Sandpaper: particle size 180.
• 5.18 Chromic acid cleaning solution: place 20 g potassium dichromate in a 1 L beaker, add a small amount of water to dissolve, then slowly add 400 mL concentrated sulfuric acid while stirring; the prepared cleaning solution should be dark red.
• 5.1 Graduated cylinder: 5 mL, 4 pieces.
• 5.2 Stopwatch: graduation 0.1 s (source-text extraction displays "OAS", requires confirmation against the source standard (source-text extraction)), one piece.
• 5.3 Platform balance: maximum weighing 200 g, sensitivity 0.2 g.
• 5.4 Beaker: 1000 mL one piece; 100 or 200 mL one piece.
• 5.5 Dropper with nipple: one piece.
• 5.9 Soap film flowmeter: 5 mL, scale division value 0.1 mL.
• 5.12 Glassware for test oil circulation: for the schematic diagram, see Figure 5; before use, the reaction tube should first be soaked in chromic acid cleaning solution, washed clean, and dried for later use.
• 5.16 Oil storage cup: dimensions as in Figure 5, material is ordinary hard glass.

5. Instruments and equipment

• 4 Use a RGY-911 type heat tube oxidation tester; other heat tube oxidation testers having the same function as 4.1 may also be used.
• 4.1 For the instrument flow diagram, see Figure 1 (the original text "Figure to" is source-text extraction noise, requires confirmation against the source standard (source-text extraction)). The instrument is provided with four channels and can simultaneously determine 4 oil samples. The temperature control is adjustable between 200—500 ℃, with an accuracy of 0.2 ℃. The oxidation pressure is 0.005—0.15 MPa, and the flow rate is adjustable between 0.05—10.0 mL/min, with an accuracy of 0.02 mL/min; the maximum difference among channels is not greater than 2% of the average value. The test oil flow rate is adjustable between 0.05—200 mL/min, with an accuracy of 5% of the average value.
• 4.2 Temperature controller: use a fully integrated advanced intelligent temperature controller, equipped with a EU2 type sheathed thermocouple (Φ4 mm × 800 mm); the temperature display accuracy is 0.2 ℃.
• 4.3 Heating furnace: vertical tubular resistance furnace (Φ50 mm × 260 mm), power 1.3 kW, with a copper sleeve and an aluminum (or copper) furnace core installed in the furnace chamber, as shown in Figure 2.
• 4.4 Gas flow control system: the connecting pipeline is a stainless steel tube with outer diameter Φ1 mm±0.3 mm and inner diameter Φ2 mm±0.3 mm (source-text extraction numerical doubt, requires confirmation against the source standard (source-text extraction)); the dryer is a metal cylinder of Φ30 mm × 250 mm, containing color-changing silica gel; when more than one half of the color-changing silica gel has changed color, it must be replaced immediately. See Figure 3.
• 4.5 Test oil delivery control system: first, a silicone rubber tube connects the reflux tube, and then it is connected to the side tube of the oil/oxygen mixer through the electronic peristaltic pump pressure groove. The silicone rubber tube has outer diameter Φ1.0 mm±0.3 mm, inner diameter Φ1.3 mm±0.2 mm, and each tube is 600—630 mm long (source-text extraction displays "601) one 630mm", requires confirmation against the source standard (source-text extraction)).
• 4.5.1 Electronic peristaltic pump: LDB-AB combined type, mixing two groups of six channels, the rotation speed and rotation speed synchronism of the left and right pump heads are adjustable, speed control dial code 0—99, liquid pumping flow rate is adjustable between 0.05—200 mL/min.
• 4.5.2 Mixer: see Figure 4; material is 1Cr18Ni9Ti.

6. Recommended operating conditions

• 6.1 Furnace core temperature calibration: use a UJ-31 type low-resistance potentiometer to calibrate the temperature controller indication and the temperature distribution of the furnace core through-hole; when the control temperature is 300 ℃, the temperature change within the middle part of the through-hole over a length of 8 cm shall not exceed ±1 ℃, and the temperature change within a length of 13 cm shall not exceed ±2 ℃. Calibrate once a year by metrological calibration personnel, and calibrate promptly if there is any abnormality.
• 6.2 Oxygen flow calibration: use the soap film flowmeter calibration method. During calibration, the oxygen cylinder pressure should be greater than 6 MPa, first adjust the pressure reducing valve output pressure to 0.3 MPa±0.05 MPa, then use the pressure stabilizing valve of the 1—4 channel gas circuit of the heat tube instrument control box to accurately adjust the pressure to 0.1 MPa±0.02 MPa, carefully adjust the gas circuit precision fine-tuning needle valve so that the volume of gas flowing out of the soap film flowmeter within 80—85 s is 2 mL; at this time the oxygen flow value is 1.5—1.4 mL/min (the original order is as such, requires confirmation against the source standard (source-text extraction)). Record the number of turns marked on the needle valve handles of the four channels. Calibrate once a month, and calibrate promptly if there is any abnormality.
• 6.3 Test oil flow calibration:
  • 6.3.1 Preliminary calibration with water: take the silicone rubber tube specified in this standard, insert it into the rolling groove of the peristaltic pump and press it tightly; the insertion length should be 98—105 mm; set the peristaltic pump to the "fast" and "forward" positions, use water as the fluid, measure the outflow volume and time, carefully adjust the peristaltic pump dial code number so that the water outflow rate is within the range of 1.05—1.25 mL/min, and record the dial code numbers selected for the left and right pump heads.
  • 6.3.2 Test oil calibration: replace the silicone rubber tube, and install the reaction tube and reflux tube according to Figure 1. Fill the oil storage cup with 5.0 g±0.2 g of test oil (take any test oil, see clause 3.4; the original text "clause 3.4" is doubtful, requires confirmation against the source standard (source-text extraction)), install according to 5.3.1 (the original text is as such, suspected to be 6.3.1, requires confirmation against the source standard (source-text extraction)) and connect the outlet of the silicone rubber tube to the side tube of the mixer; after the furnace temperature is controlled to 300 ℃±0.2 ℃, supply oxygen according to 6.2, start the peristaltic pump, and after 10 min, record the volume of hot oil flowing out within 2 min, which should be within the range of 2.1—2.5 mL; if it exceeds the flow range, it can be adjusted by tightening and loosening the silicone rubber tube to change the insertion length, and record the dial code number and the exact length of the inserted silicone rubber tube. Calibrate once a month, and calibrate promptly if there is any abnormality.
• 6.4 Calibration of the instrument: before testing each batch of samples, according to the test steps in Chapter 7, select two standard oils of different levels for calibration; the determination results should be consistent in order with the grades given for the standard oils, and the grade difference and grade shall not exceed one grade.
• 6.5 Check the heating system: the thermocouple should be inserted into the furnace core probe hole all the way to the bottom, with the cold junction placed in ice water; then set each temperature control parameter.
• 6.6 Check the gas circuit system: the oxygen pressure of the oxygen cylinder should be greater than 6 MPa, adjust the pressure reducing valve output to 0.3 MPa±0.05 MPa, adjust the pressure stabilizing valve to 0.1 MPa±0.02 MPa, and check the number of turns of the fine-tuning valve, which should match the recorded value calibrated in clause 6.2.
• 6.7 Insert the silicone rubber tube into the rolling groove of the peristaltic pump according to the exact length measured in 6.3.2 and press it tightly; set the peristaltic pump to the "fast" and "forward" positions, turn on the switch, and run for about 2 min, observing the operation of the peristaltic pump.
• 6.8 Weigh 5.0 g±0.2 g of test oil and place it on the heating furnace support.
• 6.9 Insert the reflux tube into the fixing hole of the support, with the upper end inserted to the bottom of the oil storage cup, and the lower end connected to the silicone rubber tube; the silicone rubber tube passes through the pump groove and is connected to the side tube of the mixer.
• 6.10 Take four reaction tubes and carefully insert them into the through-holes of the furnace core; the reaction tubes should slide up and down and rotate freely in the holes; insert the lower ends of the reaction tubes into the upper end of the oil/oxygen mixer, tighten the sealing nuts, and at the same time place the upper end outlets of the reaction tubes about 3—5 mm above the center of the oil storage cup.
• 6.11 Add ice cubes to the thermos bottle at the cold junction of the thermocouple to form an ice-water system.
• 7.5 After heating for about 65 min, for CC grade diesel engine oil, when the temperature controller displays a furnace temperature of 300 ℃±0.3 ℃, for CD grade diesel engine oil 320 ℃±0.3 ℃ (or another temperature), turn on the power switches of the left and right pump heads of the peristaltic pump, start oil delivery, start timing, and the test officially begins. Note: For other oils, other test conditions may also be selected.
• 7.6 Within 5 min after the peristaltic pump starts, attention should be paid to observing whether oil leaks at the compression nut of the oil/oxygen mixer and the oil and gas flow state at the bottom of the reaction tube; and record the furnace temperature fluctuation (within 20 min after startup, the displayed furnace temperature is allowed to fluctuate by ±0.6 ℃).
• 7.7 Record the furnace temperature and observed test phenomena once every 20 min (such as the operation of the peristaltic pump, oxygen pressure, oil-gas mixing, and color change of the test oil, etc.).
• 7.8 When oil delivery reaches 4 h (or the set reaction time), stop the test.

7. Sampling and Sample Preparation

• 6.8 Weigh 5.0 g±0.2 g of test oil and place it on the heating furnace support.
• 6.9 Insert the reflux tube into the fixing hole of the support; the upper end should be inserted to the bottom of the oil storage cup, and the lower end should be connected to a silicone rubber tube; the silicone rubber tube passes through the pump groove and is connected to the side tube of the mixer.
• 6.10 Take four reaction tubes and carefully insert them into the through holes of the furnace core; the reaction tubes should slide up and down and rotate freely in the holes; insert the lower ends of the reaction tubes into the upper end of the oil/oxygen mixer, tighten the sealing nuts, and at the same time place the upper outlet of the reaction tubes about 3—5 mm above the center of the oil storage cup.
• Other sampling and sample preparation requirements: not provided in the available source.

8. Analytical Procedure

• 7.1 Turn on the power of the control box. At this time the indicator light is on, and the voltage display is 220 V±10 V.
• 7.2 Turn on the temperature controller; at this time the heating furnace begins programmed heating.
• 7.3 Turn on the power switch of the printer; the power indicator light is on; press the start (set) key, and the printer begins to work.
• 7.4 Press 6.2 to supply oxygen.
• 7.5 After heating for about 65 min, for CC grade diesel engine oil, when the temperature controller displays a furnace temperature of 300 ℃±0.3 ℃, for CD grade diesel engine oil 320 ℃±0.3 ℃ (or another temperature), turn on the power switches of the left and right pump heads of the peristaltic pump, start oil delivery, start timing, and the test officially begins. Note: For other oils, other test conditions may also be selected.
• 7.6 Within 5 min after the peristaltic pump starts, attention should be paid to observing whether oil leaks at the compression nut of the oil/oxygen mixer and the oil and gas flow state at the bottom of the reaction tube; and record the furnace temperature fluctuation (within 20 min after startup, the displayed furnace temperature is allowed to fluctuate by ±0.6 ℃).
• 7.7 Record the furnace temperature and observed test phenomena once every 20 min (such as the operation of the peristaltic pump, oxygen pressure, oil-gas mixing, and color change of the test oil, etc.).
• 7.8 When oil delivery reaches 4 h (or the set reaction time), stop the test.
• 7.9 Turn off the temperature controller and stop heating.
• 7.10 Lift the upper part of the reflux tube out of the oil storage cup and place it on the support aluminum plate.
• 7.11 Move the upper outlet of the reaction tube from above the oil storage cup by a certain angle, use a graduated cylinder to collect the hot oil, measure and record the volume of test oil flowing out within two minutes V (mL). Then move the reaction tube outlet back to its original position and let all the test oil in the tube flow into the oil storage cup. Calculate the test oil flow rate by the following formula: v = V/2 (mL/min) (the formula symbol source-text extraction in the source text is unclear in the source text, requires confirmation against the source standard (source-text extraction)).
• 7.12 Turn off the power to the peristaltic pump to stop its operation.
• 7.13 Loosen the compression nut at the upper end of the oil/oxygen mixer, pull the reaction tube out of the nut, and wipe off a small amount of residual test oil at the lower end with absorbent cotton. Carefully and quickly lift the reaction tube vertically out of the aluminum core, ready for rating after washing.
• 7.14 Close the right-angle valve of the gas cylinder and loosen the pressure reducing valve.
• 7.15 Detach both ends of the silicone rubber tube and remove it from the peristaltic pump roller groove.
• 7.16 Take out the reflux tube and oil storage cup.
• 7.17 Use aviation washing gasoline to drip-wash the silicone rubber tube, reflux tube, and oil storage cup until there is no residual oil, then air-dry for next use. Drip-wash the reaction tube until there is no residual test oil (if there is residual carbon on the outer wall, polish it clean with sandpaper), ready for rating by comparison with standard color tubes.

9. Qualitative and Quantitative and Calculation Formulas

• 8 Rating and test result report: After washing the reaction tubes, compare them with standard color tubes; the difference between any two of them shall not exceed one grade. The one with the most severe discoloration is designated as the thermal tube oxidation rating grade for that oil. When it is between two adjacent grades, it can be accurate to 0.5 grade.
• Report the rating grade of the sample, reported to 0.5 grade. At the same time report the test temperature, time, oxygen flow rate, test oil flow rate, etc. during rating.
• 7.11 Test oil flow rate calculation: v = V/2 (mL/min) (the formula symbol source-text extraction in the source text is unclear in the source text, requires confirmation against the source standard (source-text extraction)).
• Appendix A (standard appendix) Standard color tubes:
  • A1 According to the color of the deposited paint film on the glass tube and the length of the deposit, thermal tube deposits are divided into 0—10 grades, a total of 11 grades.
  • A2 The standards for the paint film color and deposit length of the 11 grade glass tubes constitute the standard color comparison box. It is supplied with the RGY-911 type test instrument. The period of validity is three years.
  • A3 Description of thermal tube deposit grades:
    • 0—— The reaction tube is colorless and transparent, or has a white mist-like deposit with a length not greater than 1 cm (observed against light).
    • 1—— The white mist-like deposit in the reaction tube is greater than 1 cm, transparency is reduced, or it has a very light yellow color with very good transparency.
    • 2—— The reaction tube is light yellow with good transparency.
    • 3—— The inner wall of the reaction tube is orange-yellow, length 3—4 cm, with a certain degree of transparency.
    • 4—— The deposit on the inner wall of the reaction tube has about 3—4 cm appearing brown and opaque, total deposit length 12—15 cm.
    • 5—— The deposit on the inner wall of the reaction tube has about 7—8 cm appearing brownish-brown and opaque, total deposit length 15—16 cm.
    • 6—— The deposit on the inner wall of the reaction tube appears obviously dark brown, length 4—6 cm, total deposit length 17—18 cm.
    • 7—— The length of dark brown deposit reaches 4—10 cm, black increases, transparency completely disappears, total deposit length 17—18 cm.
    • 8—— The length of black deposit reaches about 18 cm, and the length of brown deposit at both ends is about 2—3 cm.
    • 9—— The length of black carbon deposit is 20—22 cm, transparency completely disappears, and the length of brown deposit at both ends is about 2—3 cm.
    • 10—— The heated section of the reaction tube (26 cm) is entirely black carbon deposit.
  • A4 Black spots on the thermal tube: Because some lubricating base oils with low viscosity index often have a certain amount of viscosity index improver added to increase the viscosity index. Lubricating oils with viscosity index improver added are prone to decompose into small black spots during thermal tube method simulated evaluation of detergency. This is especially obvious when evaluating CD grade test oil with the temperature set at 320 ℃. At this time, when rating thermal tubes lower than 5 grade, in addition to still determining the grade according to the above deposit description, for thermal tubes with many black spots, add 0.5 grade during rating.
• Appendix B (standard appendix) Standard oil samples:
  • B3 (the numbering in the source text is as such, requires confirmation against the source standard (source-text extraction)) This standard specifies six standard oil samples. Three are used for CC grade rating, and the other three are used for CD grade rating.
  • The standard oil samples for CC grade diesel engine oil are: CC- standard 1 second grade; CC- standard 2 fourth grade; CC- standard 3 sixth grade.
  • The standard oil samples for CD grade diesel engine oil are: CD- standard 1 first grade; CD- standard 2 third grade; CD- standard 3 seventh grade.
  • The period of validity of the standard oil is two years; it should be stored in a brown, sealed bottle, protected from light and kept ventilated.

10. Precision

• 9.1 Repeatability: For the same operator, same equipment, in the same laboratory, the difference between two repeated determination results shall not be greater than one grade.
• 9.2 Reproducibility: For different operators and different laboratories, the difference between two respective determination results shall not be greater than two grades.

11. Report

• Report the rating grade of the sample, reported to 0.5 grade.
• At the same time report the test temperature, time, oxygen flow rate, test oil flow rate, etc. during rating.
• Other reporting requirements: not provided in the available source.

12. Referenced Documents

• GB/T 6682 Water specifications and test methods for analytical laboratory use
• SH 0114 Aviation washing gasoline

13. Source and verification

This page is an AI translation of the available Chinese method card. Human verification is pending. It is not an official translation of the standard. Check the source standard and product certificate before use.

14. Quick Reference Q&A