SH/T 0667-1998 Air-cooled two-stroke gasoline engine oil detergency evaluation method

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Card type: Test method

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

• Standard number: SH/T 0667-1998
• Chinese name: Air-cooled two-stroke gasoline engine oil detergency evaluation method
• English name: Detergency test procedure for evaluating air-cooled two-stroke gasoline engine oils
• Replacement relationship: not provided in the available source
• Adoption relationship: This standard equivalently adopts the Japanese Automobile Standards Organization JASO M341-92 "Test Procedure for Evaluating Detergency of Two-Stroke Gasoline Engine Oils"
• Approval/implementation: approved by China Petrochemical Corporation 1998-09-24, implemented on 1999-04-01
• Responsible organization: Sinopec Research Institute of Petroleum Processing
• Drafting organizations: Tianjin Internal Combustion Engine Research Institute, Maoming Petrochemical Company Research Institute
• Drafters: Xie Shiwen, Wu Weida, Gong Yuying, Liang Gaosheng, Liu Chengke, Lin Yuesheng

2. Scope of application and non-applicability

• This standard specifies a test method for evaluating the detergency of air-cooled two-stroke gasoline engine oils (abbreviated as two-stroke oils), namely the tendency of piston rings to stick at high temperatures and the degree of cleanliness of engine pistons, cylinder heads, spark plugs, exhaust ports, etc.
• This standard applies to evaluating two-stroke oils used in two-stroke gasoline engines such as motorcycle engines, general-purpose gasoline engines, and snowmobile power units.
• Not applicable: not provided in the available source.

3. Method principle

This standard uses a single-cylinder, air-cooled two-stroke gasoline engine with a displacement of 49.4 cm³ to conduct the detergency test. After the engine is operated under specified conditions, the degree of piston ring sticking and the formation of deposits on the piston and cylinder head caused by the lubricating oil are evaluated.

The engine is operated at 6000 r/min, low load for 10 min, and then at wide-open throttle, full load (carbon monoxide concentration in exhaust 6.0%±0.5%(V/V)) for 60 min.

Using JATRE-1 reference oil, the test oil and reference oil are tested in the specified order on the same day, with a fuel oil/lubricating oil volume mixing ratio of 100:1.

4. Reagents and materials (purity / preparation)

4.1 Fuel oil

Use test fuel oil having the properties shown in Table 2. For the same series of evaluation tests, the same batch of fuel oil must be used.

Table 2 Test fuel oil properties

Other measured items comply with SH 0041 standard.

4.2 Standard reference oil and calibration oil

• JATRE-1 is the standard reference oil for evaluating detergency.
• JATRE-1, JATRE-3 are calibration oils.
• Their performance is shown in Appendix A.

Table A1 Standard reference oil and calibration oil

Table A2 Main properties of standard reference oil and calibration oil

4.3 Preparation of mixed fuel oil

• Both the standard reference oil and the test oil are mixed with fuel oil at a ratio of 1:100(V/V), with each used in an amount of 4 L.
• The mixed fuel oil used for break-in has a mixing ratio of 50:1(V/V), and the lubricating oil is JATRE-1 standard reference oil.
• When the mixed fuel oil shows stratification, the test must be terminated and noted in the report.

5. Instruments and equipment

5.1 Test engine

The engine used for the evaluation test is a HONDA AF27 type motorcycle SK50MM type engine, with an aluminum cylinder block and cast iron cylinder liner. The main technical parameters are shown in Table 1.

Table 1 Main technical parameters of the engine

5.2 Engine modification

• 5.2.1 Remove the power transmission components from the crankshaft to the rear axle, and output power directly from the crankshaft.
• 5.2.2 Modify the air guide shroud so that the cold air after cooling the cylinder block does not blow toward the carburetor (see Figure 1). Remove the cold air deflector in the shaded area and block the air outlet on the carburetor side.
  • 5.2.2.1 Seal the air outlet facing the carburetor side so that the cold air flows directly to the tail end.
  • 5.2.2.2 Remove the deflector facing the carburetor so that the cold air flows evenly to the tail end.
• 5.2.3 Oil pump: The premixed fuel oil does not use the oil pump; the oil pump inlet and outlet must be short-circuited, the carburetor oil supply hole must be blocked, and the oil pump must be filled with two-stroke oil to prevent the plunger from seizing.
• 5.2.4 The test does not use a fuel oil pump; the oil pump suction pipe installed on the crankcase must be blocked.
• 5.2.5 Use aluminum, steel, or fiberglass-reinforced plastic and other materials to make a heat shield, installed between the air filter and the muffler, to minimize the influence of the exhaust pipe and cooling fan on the intake air temperature (see Figure 2).

5.3 Dynamometer

The selected dynamometer should have characteristics satisfying absorption power 2.0 kW at 4000 r/min, and absorption power 4.0 kW at 6000 r/min. It is best to connect it directly to the engine crankshaft, or it may be connected to the engine through a reduction device, but transmission efficiency compensation must be performed. The dynamometer should preferably have a reverse drive function, or a starting motor may be installed for ease of operation.

5.4 Cooling system

Remove the engine's own cooling fan and use an external air source for cooling. It is recommended to use a 4 centrifugal blower driven by a 5.5 kW motor, with the air volume controlled by a damper in the pipeline. The cooling air outlet size is diameter 180 mm. The air speed should be adjusted so that during engine break-in the spark plug gasket thermocouple temperature tₛ is not higher than 180℃, and the rated condition temperature tₛ is not higher than 240℃. If conditions do not permit, the original engine cooling system may also be used.

5.5 Exhaust system

The engine exhaust pipe is placed in an exhaust extraction system. It is recommended that this system be equipped with a 4 axial exhaust fan driven by a 0.6 kW explosion-proof motor. Use a pipe of length 150 mm and diameter 8 mm, install a K type thermocouple to measure exhaust temperature (tₑ), and install the thermocouple at a distance of 50 mm from the exhaust pipe inlet according to conventional requirements.

5.6 Spark plug gasket thermocouple

Install a K type thermocouple in the spark plug gasket (see Figure 3, Figure 4), and control the engine thermal load by controlling the gasket temperature (tₛ).

5.7 Carbon monoxide concentration and intake air temperature measurement

To control the operating state of the engine, in addition to measuring tₛ and tₑ, it is also necessary to measure the intake air temperature of the air cleaner (t₀) and the carbon monoxide concentration in the exhaust; the measurement locations are shown in Figure 5 and Figure 6.

5.8 Fuel oil supply system

The fuel oil tank capacity is 4 L, higher than the float chamber liquid level by 500 mm; fuel oil is supplied by pressure head rather than by a fuel oil pump. The pressure loss of the oil pipe should be minimized as much as possible, and its routing should avoid the occurrence of pipeline vapor lock (see Figure 7).

5.9 Instruments and meters for testing

• 5.9.1 The torque measurement range of the dynamometer is 0 N·m~10 N·m, and the measurement accuracy is ±0.05 N·m.
• 5.9.2 The rotational speed measurement accuracy of the tachometer is ±10 r/min.
• 5.9.3 The measurement ranges of the thermometer for various temperatures are respectively: cylinder head 0–400℃ (the cylinder-head temperature measurement range is garbled in the source transcription and requires verification); exhaust 0–800℃; intake 0–100℃; the accuracy is ±1℃ for all. The measurement range of the wet-and-dry bulb thermometer is -55–+55℃, and the accuracy is ±1℃.
• 5.9.4 The recorder can continuously record exhaust, intake, and cylinder head temperatures; if continuous recording cannot be achieved, data must still be collected once every 10 min.
• 5.9.5 Fuel oil flow meter: measurement range is 0~3.0 L/h, measurement accuracy is ±0.05 L/h.
• 5.9.6 Carbon monoxide concentration measuring instrument: range is 0~10%(V/V), measurement accuracy is ±0.1%(V/V).
• 5.9.7 Barometer: measurement range is 31~110 kPa, measurement accuracy is ±0.1 kPa.

6. Recommended operating conditions

6.1 Break-in operating conditions (Table 3)

In the second stage of break-in, the throttle is fully open, the exhaust carbon monoxide concentration should reach 6.0%±0.5%(V/V), and the minimum output torque is 4.25 N·m. If it is not within this range, the carburetor main nozzle and needle position should be adjusted; it is generally recommended to use the No.78 main nozzle and to place the needle lock ring at the third position from the top downward.

6.2 Pre-operation conditions (Table 4)

The content of Table 4 in the source text is source-text extraction missing, not provided in the available source.

6.3 Evaluation test operating conditions (Table 5)

Note: Parameters in parentheses are reference values.

7. Sampling and test sample preparation

7.1 Preparation of the engine

• 7.1.1 Engine assembly: For each cleanliness test of the reference oil and the sample oil, new parts shall be installed in accordance with the requirements of Appendix B; the assembly procedure shall be carried out in accordance with the manufacturer's maintenance manual; during assembly, a thin layer of sample oil shall be applied to the surfaces of the parts.
• 7.1.2 Break-in: For a new engine or an engine in which cylinder and crankshaft system parts have been replaced, break-in must be carried out according to the operating conditions in Table 3.
• 7.1.3 Engine adjustment and repair: When the engine speed is 6000 r/min and the decrease in full-load output power exceeds 10%, engine adjustment and repair are required; if necessary, replace the engine with a new one, or adjust and replace parts in accordance with the manufacturer's maintenance manual.

7.2 Preparation of mixed fuel oil for evaluation testing

Both the standard reference oil and the sample oil are mixed with fuel oil in the ratio 1:100(V/V), with each used in an amount of 4 L. If stratification occurs in the mixed fuel oil, the test must be terminated and noted in the report.

7.3 Preparation of the fuel oil supply system

When changing the sample oil, drain the mixed fuel oil from the fuel oil tank, fuel oil pipe, flow meter, and carburetor, and rinse the fuel oil tank with the sample oil. When new mixed fuel oil is poured into the fuel oil tank, the drain screw of the carburetor float chamber should be loosened to discharge about 100 mL of mixed fuel oil.

7.4 Pre-operation

After completing the break-in operation, before the formal evaluation test, the engine shall be pre-operated according to Table 4 (the content of Table 4 is not provided in the available source).

8. Analytical procedure

• 8.1 After pre-operation, continue to open the throttle further until fully open, and conduct the test according to the operating conditions in Table 5. The tests of the standard reference oil and the sample oil are conducted on the same day to eliminate the influence of changes in environmental conditions. During the test, at least once every 10 min, measure the engine speed n, output torque Mq, spark plug gasket temperature tₛ, exhaust temperature tₑ, intake temperature t₀, fuel oil consumption, and exhaust carbon monoxide concentration, for a total of 7 parameters. At the beginning and end of the evaluation test, record the dry-bulb temperature, wet-bulb temperature, laboratory ambient temperature, and atmospheric pressure, for a total of 4 parameters, as shown in Table 6.
• The main factor affecting the evaluation test is the carbon monoxide concentration. When the concentration value is not within the range specified in Table 5, the engine must be readjusted, and the test must be restarted from the second stage of break-in.
• 8.2 After operating for 1 h under the conditions in Table 5, stop the engine, and the test ends. After natural cooling for 30 min, disassemble the engine. Remove the piston from the engine, first evaluate the sticking condition of the piston rings, then gently clean the piston for several seconds with solvent naphtha No. NY-190 among GB 1922.

9. Qualitative and quantitative evaluation and calculation formulas

9.1 Scoring

The cleanliness scoring of parts shall be carried out according to the method specified in Appendix C.

9.1.1 Parts to be scored

a) Piston rings (sticking condition of the top ring and second ring); b) Piston ring lands (top ring land and second ring land); c) Piston ring grooves (top ring groove and second ring groove); d) Piston skirt; e) Piston top inner cavity; f) Piston crown; g) Cylinder head.

Note: When evaluating the ring groove surfaces that contact the expansion ring, it is assumed that the deposits on the two contacting side surfaces are continuous, and deposits scraped off at the boundaries of the contact surfaces due to the movement of the expansion ring are ignored.

9.1.2 Weighted scoring

The cleanliness correction coefficients (weighting coefficients) are used to correct the score of each part; the weighted score is calculated according to formula (1); the cleanliness weighting coefficients are given in Appendix C, C6.

Weighted score = merit score × weighting coefficient ………………(1)

9.1.3 Commentary

a) Spark plug damage condition; b) Blockage condition of the exhaust port; c) Damage and wear condition of the piston pin and connecting rod small end bearing; d) Wear of the crankshaft main bearings and connecting rod big end bearings, etc.

9.1.4 Form filling and photography

Fill the evaluation results and test measurement parameters into Table 7 and Table 8. Take color photographs of the evaluated parts at the following locations: cylinder head combustion chamber surface, piston crown surface, piston inner cavity, exhaust-side piston surface, intake-side piston surface, piston surface in the direction of the right piston pin hole, piston surface in the direction of the left piston pin hole, and spark plug electrode and gap, for a total of 8 photographs, and indicate the test number, sample oil, test date, and cleanliness index.

9.2 Cleanliness index DIX

The cleanliness index is calculated according to formula (2) and recorded in Table 8.

DIX = sum of weighted scores of each part for the sample oil / JATRE-1 sum of weighted scores of each part for the standard reference oil × 100 ………………(2)

9.3 Piston skirt lacquer film index VIX

The piston skirt lacquer film index is calculated according to formula (3) and recorded in Table 8.

VIX = sum of weighted scores of each side of the piston skirt for the sample oil / JATRE-1 sum of weighted scores of each side of the piston skirt for the standard reference oil × 100 ………………(3)

Note: The cleanliness index shall be reported as an integer after rounding.

Appendix C Cleanliness scoring method

C1 Piston ring sticking scoring (Table C1)

C2 Scoring of lacquer film and deposits on piston ring grooves, ring lands, skirt, and piston top inner cavity

Deposits with a thickness less than 0.1 mm are scored for lacquer film according to color grade; based on the SH/T 0510 color grades, determine the color scoring weighting coefficient and area percentage for each part.

For the piston skirt, the scoring area is limited to the contact surface, excluding the area around the piston pin, that is, the part not in contact with the cylinder liner.

For the scoring area of the piston top inner cavity, it refers to the area from the top of the piston inner cavity to above the lowest piston ring groove. For irregular shapes, determine the area of each component separately. Use formula (C1) to calculate the total merit score.

Total merit score = Σ( color rating weighting coefficient × area, %)/100 ………………(C1)

C3 Piston top and cylinder head deposit rating

Using the deposit rating weighting coefficients given in Table C2 and calculation formula (C2), calculate the total deposit merit score.

Total merit score = Σ( deposit rating weighting coefficient × area, %)/100 ………………(C2)

C4 Exhaust port blockage rating

Refers to the percentage of the exhaust port area blocked by deposits; calculate the merit score according to formula (C3).

Merit score = 10 - (blocked area, %/100) ………………(C3)

C5 Spark plug condition

Describe the spark plug condition visually, using the expressions provided below:

• Normal deposits
• Center electrode bridging
• Gap bridging
• Pre-ignition
• Other

C6 Cleanliness weighted rating (Table C3)

10. Precision

not provided in the available source.

11. Report

• Fill the evaluation results and test measurement parameters into Table 7 and Table 8.
• Take color photographs of the evaluated parts, 8 photographs in total, and indicate the test number, sample oil, test date, and cleanliness index.
• Report the cleanliness index as an integer after rounding.
• When stratification occurs in the mixed fuel oil, the test must be terminated and noted in the report.
• The specific formats of Table 7 and Table 8 are source-text extraction severely missing in the original text; not provided in the available source.

12. Referenced documents

• 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
• GB/T 1995 Petroleum products—Calculation of viscosity index
• GB/T 2433 Determination of sulfate ash in additives and additive-containing lubricating oils
• GB/T 5363 Test method for engine bench testing of motorcycles and mopeds
• GB/T 5487 Determination of gasoline octane number (research method)
• GB/T 6536 Petroleum products—Determination of distillation
• GB/T 7304 Determination method for neutralization value of petroleum products and lubricants (potentiometric titration method)
• GB/T 8017 Petroleum products—Determination of vapor pressure (Reid method)
• GB/T 8019 Determination of existent gum in automotive gasoline and aviation fuels (jet evaporation method)
• GB/T 8020 Determination of lead content in gasoline (atomic absorption spectrometry)
• GB/T 11132 Determination of hydrocarbon types in liquid petroleum products (fluorescent indicator adsorption method)
• SH 0041 Unleaded automotive gasoline
• SH/T 0510 Rating method for engine tests of gasoline engine oils

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

• Original standard number GB/T 7304-87 → current standard number GB/T 7304, current standard name: Determination method for neutralization value of petroleum products and lubricants (potentiometric titration method)
• Original standard number SH 0041 → current standard number SH 0041-93, current standard name: Unleaded automotive 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.

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