SH/T 0669-1998 Air-cooled two-stroke gasoline engine oil exhaust system blockage evaluation method

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Card type: Test method

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

• Method number: SH/T 0669-1998
• Chinese full name: Air-cooled two-stroke gasoline engine oil exhaust system blockage evaluation method
• English name: Exhaust system blocking test procedure for evaluating air-cooled two-stroke gasoline engine oils
• Replacement relationship: not provided in the available source (the foreword only states equivalent adoption of JASO M343—92, and does not list replaced standards)
• Adoption relationship: equivalent adoption of Japan Automobile Standards Organization JASO M343—92 "Test Procedure for Evaluating Exhaust System Blocking of Two-Stroke Gasoline Engine Oils"
• Approval/implementation: approved by China Petrochemical Corporation 1998-09-24, implemented on 1999-04-01
• Responsible organization: Sinopec Group Petroleum Processing Research Institute
• Drafting organizations: Tianjin Internal Combustion Engine Research Institute, Maoming Petrochemical Company Research Institute
• Main drafters: Gong Yuying, Wu Dawei, Xie Shiwen, Lin Yuesheng, Lan Jun, Liang Qirui

2. Scope of application and non-applicability

• Scope of application: specifies a test method for evaluating the tendency of air-cooled two-stroke gasoline engine oils (abbreviated as two-stroke oils) to prevent engine exhaust system blockage; applicable to evaluating two-stroke oils used in two-stroke gasoline engines such as motorcycle engines, general-purpose gasoline engines, and snowmobile power units.
• Non-applicability: no explicit non-applicability clause is provided in the available source.
• Special circumstances: if the two-stroke oil and standard fuel oil separate into layers after mixing, the test shall no longer be conducted, and this shall be noted as a special circumstance in the report (see 7.2).

3. Method principle

This test uses a SX-800R generator equipped with a single-cylinder, forced air-cooled two-stroke engine with a displacement of 69cm³. Due to blockage of the exhaust system by carbon deposits, the engine output power decreases. This test evaluates the tendency of the two-stroke oil to prevent exhaust system blockage by comparing the duration of continuous operation until the engine intake negative pressure reaches a specified value.

This test uses two mixed fuel oils separately mixed with standard reference oil and sample oil, with a mixing ratio (standard fuel oil/two-stroke oil) of 5:1. Two test engines use different mixed fuel oils and operate continuously simultaneously according to the operating mode shown in Figure 10. After completing the test, the mixed fuel oils of the two engines are exchanged, and then a second test is conducted under the same conditions as the first, thereby obtaining two test results each for the sample oil and the standard reference oil. Evaluation is performed by calculating the blockage index.

4. Reagents and materials (purity / preparation)

• Standard fuel oil: use standard fuel oil having the characteristics in Table 2; the same batch of standard fuel oil must be used for the test of the same sample oil (because a relative comparison is made between the sample oil and the standard reference oil). Other measurement items comply with SH 0041 standard.
• Standard reference oil: this standard uses JASO JATRE-1 two-stroke oil (performance see Appendix A).
• Calibration oil: this standard uses JASO JATRE-1 and JATRE-3 two-stroke oils (performance see Appendix A).
• Mixed fuel oil preparation: standard fuel oil is mixed with standard reference oil and sample oil respectively at 5:1 (V/V) (see 7.2).
• Break-in oil: a two-stroke oil equivalent to the standard reference oil, mixing ratio 50:1 (V/V) (see Table 3).

Table 2 Properties of standard fuel oil (quality indicators / test methods):

Appendix A Table A1 Standard reference oil and calibration oil:

Appendix A Table A2 Main properties of standard reference oil and calibration oil:

5. Instruments and equipment

5.1 Test engine: SUZUKI generator SX-800R; single-cylinder, forced air-cooled; bore × stroke 46.0×42.0 mm; displacement 69.8 cm³; compression ratio 5.6 (see Table 1). 5.1.1 Engine modification

• 5.1.1.1 Muffler: do not use the original standard muffler; purchase a muffler equipped with a screen according to Table 4, and modify it with reference to Figure 1:
  • a) For internal modification of the muffler, refer to Figure 2, drill holes at the 6 weld points on the muffler box, cut off the pressed edges around the perimeter, open the box, remove the internal ducts, partitions, and glass wool, then join the box, weld the perimeter, and weld shut the holes at the weld points to restore the muffler, and confirm there is no air leakage.
  • b) Remove the heat insulation plate; with reference to Figure 3, drill holes at the 4 weld points, remove the heat insulation plate, and then weld shut these holes.
  • c) With reference to the standard muffler and Figure 1, prepare a cover plate as shown in Figure 4, welded together with the exhaust sampling tube and exhaust pressure measurement tube, to measure the carbon monoxide concentration in the exhaust and the exhaust pressure.
  • d) To insulate the muffler, cover the muffler with 500mm×300mm, thickness 200mm glass wool, as shown in Figure 5.
  • e) Modification of the muffler shield, as shown in Figure 6, modify the muffler shield, and install a thermal insulator at the removed portion.
  • f) Change the position of the muffler support point, as shown in Figure 7.
• 5.1.1.2 Intake pipe: install an intake pipe on the reed valve body to measure engine intake negative pressure, as shown in Figure 8. 5.2 Load absorption system: select a resistive load absorption system that meets the test requirements to control the electrical load, see Figure 9 (load resistance 50Ω/1kW 2×2-2/50 type; voltage regulator 3kVA TDGC-3 type; ammeter 10A 6LZ). 5.3 Control system: the control equipment is required to meet the operating conditions of Figure 10, and to automatically connect and disconnect the 60Hz, 750W±15W electrical loads at the specified exhaust temperature. See Figure 14, equipped with the following equipment.
• 5.3.1 Temperature controller: temperature control range 0~600℃.
• 5.3.2 Relay: commercially available explosion-proof electronic relays may be used. 5.4 Measurement equipment: equipped with the following measurement equipment and connected to a recorder, see Figure 14.
• 5.4.1 Thermometer: accuracy 1℃, with an output terminal for connection to a measurement recorder.
• 5.4.2 Exhaust pressure gauge: range 0~20kPa, with an output terminal for connection to a measurement recorder.
• 5.4.3 Intake pressure gauge: range 0~10kPa, with an output terminal for connection to a measurement recorder.
• 5.4.4 Recorder: a pen-type recorder capable of continuous measurement should be selected.
• 5.4.5 Counter: an instrument capable of recording the number of on-off transitions should be selected.
• 5.4.6 Carbon monoxide concentration measuring instrument: measurement concentration range 0~10% (V/V), accuracy 0.1% (V/V).
• 5.4.7 Dry and wet bulb thermometer: measurement accuracy ±1℃.
• 5.4.8 Barometer: measurement accuracy ±0.1kPa.
• 5.4.9 Tachometer: measurement accuracy ±10r/min, can be connected to a recorder. 5.5 Temperature measurement positions
• 5.5.1 Exhaust temperature: refer to Figure 11 to prepare an exhaust temperature sensor, install it at the bolt indicated in Figure 2, so that its tip is at the center of the exhaust pipe.
• 5.5.2 Spark plug gasket temperature: an example of a spark plug gasket thermocouple is shown in Figure 12, and its installation position is shown in Figure 13. 5.6 Fixing of the test engine: Fix the test engine on a support through four rubber vibration-damping pads, then fix the support on the test bench, see Figure 15. It is recommended to place the two engines separately so that they are not subject to thermal interference from each other and to maintain air circulation. If this cannot be achieved, install a heat shield between the two engines. 5.7 Exhaust extraction system: Discharge the exhaust gas from the engine directly outdoors. It is recommended to select an axial fan of No. 4 driven by an explosion-proof motor 0.6kW, and connect the exhaust duct to the engine muffler. 5.8 Fuel oil supply system: Figure 16 gives an example of a fuel oil supply system.
• 5.8.1 Fuel oil supply: By gravity head pressure. To ensure constant pressure, it is best to provide a fuel pressure regulator, which can be modified from a carburetor, as shown in Figure 17, installed close to the engine.
• 5.8.2 Fuel oil pipe: The fuel pipe structure used should minimize the fuel oil head pressure loss, and there must be no air bubbles in the pipeline.
• 5.8.3 Fuel oil tank: A fuel oil tank with a volume of about 10L needs to be prepared.

Table 1 Engine specifications:

Table 4 Maintenance and replacement of components (part name / part number / quantity / maintenance and replacement time / remarks):

Table 6 Main jet and auxiliary jet:

6. Recommended operating conditions

Table 5 Conditions for pre-operation and formal test:

Operating mode (Figure 10): 1.5min±0.75min; zero load (370℃); 750W±15W (330℃); 60Hz 750W±15W; 60Hz zero load.

Table 3 Break-in conditions:

7. Sampling and sample preparation

• 7.1 Engine preparation
  • 7.1.1 Break-in: For a new engine or after replacing components (cylinder, piston, piston ring, crankshaft, etc.), break-in must be carried out according to the conditions specified in Table 3 before the formal test. Break-in uses the original engine muffler.
  • 7.1.2 Inspection and maintenance: Replacement and maintenance of components shall be carried out at the times specified in Table 4. Items not listed shall be carried out according to the manufacturer's service manual.
    • 7.1.2.1 Maintenance methods for components:
      • a) Cylinder, cylinder head, piston and piston ring: The carbon deposits on these parts must be cleaned off every test. If the piston ring becomes stuck after the test, the piston and piston ring must be replaced.
      • b) Air filter: Clean the filter element every test, soak it in the mixed fuel oil used for the test after cleaning, then gently squeeze it dry by hand.
      • c) Muffler: After mechanically removing the carbon deposits at the muffler outlet, soak it in carbon removal liquid for about 24h, then rinse with tap water and air dry.
      • d) Screen: Burn the screen in fire until the carbon deposits are burned off, then rinse with tap water and air dry. The screen is installed in the muffler tail pipe, ensuring a certain degree of freedom in the pipe.
      • e) Exhaust temperature sensor: Remove the carbon deposits on it every test.
    • 7.1.2.2 Periodic inspection: After every 10 sets of tests, inspect according to the manufacturer's Service Guide.
  • 7.1.3 Engine assembly: Engines after modification and after component replacement shall be assembled according to the service guide. During installation, apply a small amount of the test two-stroke oil to the surfaces of moving parts.
• 7.2 Preparation of mixed fuel oil: The standard fuel oil is mixed with the standard reference oil and the sample oil respectively at 5:1 (V/V), but if the two-stroke oil and the standard fuel oil separate after mixing, the test shall not be continued and shall be noted in the report as a special case.
• 7.3 Preparation of the fuel supply system: Whenever the test oil is changed, the mixed fuel oil in the fuel oil tank, fuel pipe and carburetor float chamber shall be drained to eliminate the influence of the previous test.
• 7.4 Pre-operation of the engine: Before the formal test, the engine shall be pre-operated according to the conditions specified in Table 5 and the operating mode in Figure 10 to adjust the engine operating condition.
  • 7.4.1 Adjustment of engine operating conditions
    • 7.4.1.1 Engine speed: Adjust the engine speed according to the manufacturer's Service Guide.
    • 7.4.1.2 Carbon monoxide concentration: Adjust the carbon monoxide concentration starting from zero load, by adjusting the carburetor control screw to achieve the requirements of the operating conditions. If this cannot be achieved, the auxiliary jet or main jet may be replaced, preferably replacing the auxiliary jet first and then the main jet (it is recommended to equip main jets and auxiliary jets with reference to Table 6). In addition, when the total engine operating time is relatively short, the carbon monoxide concentration should be adjusted to the lower limit.
    • 7.4.1.3 Cycle time: The cycle time of the operating condition is adjusted by changing the thickness of the muffler's thermal insulation.

8. Analysis procedure

• 8.1 After completing the pre-operation, install the modified muffler according to the test requirements, and start the formal test on both engines simultaneously. After the engine has run for 10min, observe the operating condition without stopping the machine, and if it is confirmed that the specified operating conditions are met and the control equipment is reliable, continue the test.
• 8.2 If the operating conditions are not met, restart from pre-operation and readjust the engine.
• 8.3 When the intake negative pressure reaches 2kPa, the test ends. If the engine stops running due to spark plug carbon fouling, replace the spark plug, continue the test, and record the operating time before the engine stopped as a special note.
• 8.4 Recording: Record the measurement items in Table 5 in Table 7.
• 8.5 Verification of test validity: Due to certain differences between the two engines, there is a certain error when the engines are running. When the test results of the same test oil satisfy the condition of formula (1), the test is valid. If the test is invalid, the engines should be inspected and adjusted, and the operating conditions reconfirmed or a new engine used to retest.
• 8.6 Blocking index (BIX): Calculated according to formula (2), and the index value is rounded to an integer.
• 8.7 Test result report: Fill the test results into Table 7.

9. Qualitative and quantitative and calculation formulas

• Test validity condition (formula 1): Longer operating time of the same oil / shorter operating time of the same oil ≤ 1.75 (The original formula 1 is expressed as: 1.75 ≥ longer operating time of the same oil / shorter operating time of the same oil)
• Blocking index (formula 2): BIX = total operating time of sample oil / total operating time of standard reference oil Note: Total operating time refers to the sum of the first operating time and the second operating time. The index value is rounded to an integer.

Table 7 Air-cooled two-stroke gasoline engine oil exhaust blocking test report form (record items):

10. Precision

not provided in the available source (this standard does not list a precision clause; test validity is determined by 8.5 formula (1)).

11. Report

Fill the test results into Table 7 (air-cooled two-stroke gasoline engine oil exhaust plugging test report form). The report form includes test method, test number, test date, test engine, test oil name, atmospheric pressure, ambient temperature, humidity, carbon monoxide concentration, spark plug gasket temperature, intake negative pressure, exhaust pressure, number of cycles, operating time, special items, test validity confirmation, plugging index BIX, etc. If the mixed fuel oil shows stratification, note it as a special case in the report (see 7.2).

12. Normative References

The provisions of the following standards, through reference, constitute a part of this standard. Unless otherwise expressly specified in the standard, the following referenced standards shall all be currently valid standards.

• GB/T 265 Petroleum products — Determination of kinematic viscosity and calculation of dynamic viscosity
• GB/T 268 Petroleum products — Determination of carbon residue (Conradson method)
• GB/T 380 Petroleum products — Determination of sulfur content (lamp method)
• GB 1922 Solvent naphtha (original text written as CB 1922, requires confirmation against the source standard (source-text extraction))
• GB/T 1995 Petroleum products — Calculation of viscosity index (original text written as CB/T 1995, requires confirmation against the source standard (source-text extraction))
• GB/T 2433 Determination of sulfated ash from additives and additive-containing lubricating oils
• GB/T 5363 Test methods for engines of motorcycles and mopeds on test beds
• GB/T 5487 Determination of gasoline octane number (research method)
• GB/T 6536 Petroleum products — Determination of distillation
• GB/T 7304 Petroleum products and lubricants — Determination of neutralization value (potentiometric titration method) (original text written as CB/T 7304, requires confirmation against the source standard (source-text extraction))
• GB/T 8017 Petroleum products — Determination of vapor pressure (Reid method) (original text written as CB/T 8017, requires confirmation against the source standard (source-text extraction))
• GB/T 8019 Motor gasoline and aviation fuels — Determination of existent gum (jet evaporation method)
• GB/T 8020 Gasoline — Determination of lead content (atomic absorption spectrometry)
• GB/T 11132 Liquid petroleum products — Determination of hydrocarbon types (fluorescent indicator adsorption method) (original text written as CB/T 11132, requires confirmation against the source standard (source-text extraction))
• SH 0041 Unleaded motor gasoline

Editor's note (original text): The standard numbers and standard names of the referenced standards in this standard have changed as follows:

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.

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