SH/T 0788-2006 Evaluation method for high-temperature oxidation and bearing corrosion of internal combustion engine oils (Procedure VII method)

AI-translated method card — human verification pending. This is not an official translation of the standard. Unclear source values remain unverified; check the original standard and product certificate before use.

Card type: Test method

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

• Standard number: SH/T 0788—2006
• Chinese name: Evaluation method for high-temperature oxidation and bearing corrosion of internal combustion engine oils (Procedure VII method)
• English name: Standard test method for evaluation of automotive engine oils in the sequence VII spark-ignition engine (CLR oil test engine)
• Replacement relationship: not provided in the available source (the foreword does not list the replaced standard number)
• Adoption relationship: modified adoption of ASTM D6709-04 "Standard test method for evaluating internal combustion engine oils using a CLR spark-ignition test engine—Procedure VII method"
• Publication/implementation: published by 2006-05-12, implemented by 2006-11-01
• Issuing body: National Development and Reform Commission of the People's Republic of China

2. Scope of application and non-applicability

• 1.1 specifies a method for evaluating the high-temperature oxidation and bearing corrosion performance of internal combustion engine oils. Using a CLR oil test machine, with unleaded gasoline as fuel, it evaluates the high-temperature oxidation and bearing corrosion performance of internal combustion engine oils (viscosity grades include 5W, 10W, 20, 30, 40, 50 and multigrade oils) as well as the viscosity change of multigrade oils.
• The correlation between the test results of 1.2 and the results of use in automobile engines has not been established; the results obtained by this test cannot fully represent the results of all spark-ignition or compression-ignition engines under conditions different from this test method, but the oil test has good discrimination.
• 1.3 uses only [SI] units as standard units.
• 1.4 involves certain hazardous materials, operations and equipment, but does not address all safety issues related to them; users should establish appropriate safety systems and protective measures before use.

3. Method principle

• Before the 4.1 test, thoroughly clean the engine and its components and measure the main parts. Each test requires a new piston or a clean used piston, a set of new piston rings, a pair of new connecting rod bearings, and other components that need to be replaced.
• The 4.2 test is equipped with a complete auxiliary system and uses unleaded gasoline as fuel.
• The 4.3 test initially has a 4h break-in, and the operating conditions are shown in Table 1 (see 11.1).
• The 4.4 formal test is run for 40h under the conditions shown in Table 2; during the test, oil samples are taken every 10h and a corresponding amount of new oil is added.
• In the first 10h of the 4.5 test, an oil sample is taken for viscosity analysis; if the test oil sample is a multigrade oil, the viscosity of the 10h oil sample must be measured for SIG capability.
• After the 4.6 test is completed, the engine is disassembled to measure the connecting rod bearing weight loss.

Table 1 Engine break-in operating conditions

Table 2 Test operating conditions

4. Reagents and materials (purity / preparation)

• 7.1 Cleaning materials
  • 7.1.1 400, 600, 800 sandpaper.
  • 7.1.2 Emery cloth.
  • 7.1.3 Polyester tape.
  • 7.1.4 Rubber.
  • 7.1.5 Petroleum ether, meeting the GB/T 15890 specification.
  • 7.1.6 Tap water of 82℃.
• 7.2 Sealing materials
  • 7.2.1 Rubber and various gasket sealants.
  • 7.2.2 Oil-resistant silicone sealant.
  • 7.2.3 Polytetrafluoroethylene sealing tape.
• 7.3 Assembly oil: specific specification not provided in the available source
• 7.4 Reference oil: used for test bench calibration (specific grade not listed in the source text)
• 7.5 Coolant: the coolant is soft water (the source wording requires confirmation against the source standard (source-text extraction))
• 7.6 Fuel: special unleaded gasoline, technical requirements see Appendix D

Appendix D Technical requirements for test fuel (Table D1.1)

5. Instruments and equipment

• 6.1 Test engine: provided by the test engineering company (TEI), accompanied by the "CLR Test Engine Disassembly, Assembly and Maintenance Manual".
  • 6.1.1 Engine composition: a four-stroke single-cylinder gasoline engine with bore 96.5mm, stroke 95.2mm, displacement 0.696L + auxiliary equipment box (Figure 1).
  • 6.1.2 Test bearing: alloy bearing with part number SAE H-24 provided by the ASTM Procedure VII test monitoring group, TEI part number NO.100034-1.
  • 6.1.3 Crankshaft: crankshaft of the CLR test machine with TEI number 100039-1; it can be repaired and reused.
    • 6.1.3.1 The main shaft oil seal sealing area and the main journal area can be welded and then reground for reuse; after repair, the dimensions and surface roughness must meet the specification requirements.
    • 6.1.3.2 The main shaft oil seal sealing area, connecting rod journal area and main bearing journal area can be repaired by chrome plating; if a repaired crankshaft is used, a chrome-plated crankshaft must be used.
    • 6.1.3.3 Crankshaft identification: S standard crankshaft; C chrome-plated crankshaft; R repaired and ground crankshaft.
  • 6.1.4 Piston: piston of the CLR test machine with TEI number NO.2405; it can be reused when its dimensions meet the piston-to-cylinder liner clearance requirements. Pistons that have been used in the L-38 test or other leaded fuel tests cannot be used in the Procedure VII test.
    • 6.1.4.1 Clean carbon deposits on the piston top with solvent naphtha and fine sandpaper.
    • 6.1.4.2 Rinse the piston with petroleum ether.
  • 6.1.5 Piston ring assembly: install using the special piston ring removal and installation tool with number NO.4127.
• 6.2 Preparation before the test
  • 6.2.1 Typical Procedure VII engine test bench (Figure 2).
  • 6.2.2 Crankcase ventilation control system: measures and controls the crankcase ventilation rate, maintaining the specified crankcase pressure and scavenging rate.
    • 6.2.2.1 Crankcase scavenging control system, see Appendix A.
    • 6.2.2.2 Rocker cover intake flow control system, see Appendix B.
    • 6.2.2.3 Adjustable crankcase ventilation device, see Appendix C.
    • 6.2.2.4 Rocker cover intake line connection: 6.35mm stainless steel pipe (Figure 3).
    • 6.2.2.5 Crankcase breather pipe diameter 40mm, installed on the engine oil gallery side cover plate, threaded portion coated with sealant (Figure 4).
    • 6.2.2.6 Install a clean rocker cover intake surge tank (volume 3.8L–5.7L) and exhaust gas condensation tank (volume 38L–45L), the tanks are made of rust-proof material.
    • 6.2.2.7 Rocker cover air flow: measured with a 0–20L/min flow meter; adjusted with a 0–1420L/h rotameter; line inner diameter 9.5mm brass line.
  • 6.2.3 Oil filter: model LFS-62 Racor, connected with suitable hoses and fittings (Figure 6).
  • 6.2.4 Oil drain valve: install the oil drain valve at a height not exceeding the bottom of the oil pan or at the bottom of the oil heater.
  • 6.2.5 Oil heater: connected with suitable hoses and fittings (Figure 7).
  • 6.2.6 Cooling system: composed of heat exchanger, water pump, liquid regulating valve, water tank, etc. (Figure 8).
    • 6.2.6.1 Use heat exchanger number No.YR-CO-C87492.
    • 6.2.6.2 Install a regulating valve at the coolant outlet to control the temperature difference between coolant inlet and outlet; fittings made of 40mm refractory material, threaded portion coated with sealant.
    • 6.2.6.3 Select coolant water pump number No.5768.
    • 6.2.6.4 Manufacture the cooling water tank with fireproof material of diameter 150mm, height 200mm, capacity 3.5L, with an easily openable top cover on top, installed level, and a transparent tube for easily observing the coolant level must be installed.
  • 6.2.7 Exhaust system: the exhaust pipe is water-cooled.
  • 6.2.8 Engine ignition control system: adopts a mechanical ignition control system.
• 6.3 Instruments, Equipment and Control System
  • 6.3.1 Dynamometer: speed accuracy ±0.5%, load accuracy 2%.
  • 6.3.2 Fuel flow meter: volumetric flow meter, flow 0~4.5kg/h, minimum control accuracy ±1%, reproducibility within 0.5%.
  • 6.3.3 Air-fuel ratio measurement: converted from intake pressure difference and fuel flow.
  • 6.3.4 Pressure measurement system
    • 6.3.4.1 Crankcase vacuum: measurement interface point at the lower left of the oil gallery side cover plate (Figure 5).
    • 6.3.4.2 Exhaust back pressure: measurement point connected within 100mm at the cylinder head exhaust pipe flange; sensor accuracy ±10%, division value 2.5mmHg, pressure gauge range 340Pa.
    • 6.3.4.3 Intake manifold vacuum: at the bend of the intake manifold, pressure sensor with accuracy ±1%, measurement value 680Pa.
    • 6.3.4.4 Oil pressure: pressure sensor with accuracy ±2%, resolution 7kPa, measurement point as shown in Figure 5.
  • 6.3.5 Temperature measurement system
    • 6.3.5.1 Select type J thermocouple.
    • 6.3.5.2 Thermocouple diameter 3.2mm, exposed portion must not exceed 50mm.
    • 6.3.5.3 Thermocouple calibration result must be within the range of ±0.56℃.
    • 6.3.5.4 The top of the thermocouple must be placed at the center of the medium being measured; crankcase oil temperature measurement point as shown in Figure 4.
    • 6.3.5.5 Coolant inlet and outlet thermocouples are installed at 100mm outside the cylinder block coolant inlet and outlet.
    • 6.3.5.6 Intake air temperature thermocouple is installed at 38mm above the carburetor bell mouth.
    • 6.3.5.7 Main oil gallery temperature: measured before the main bearing oil gallery, the length of the thermocouple immersed in the oil gallery must not exceed 35mm.

6. Recommended Operating Conditions

• Break-in operating conditions: see Table 1 (4h break-in).
• Formal test operating conditions: see Table 2 (40h).
• Warm-up steps: see Table 3.

Table 3 Warm-up steps

• 11.3 Air-fuel ratio and ignition advance angle: adjusted as needed at 10h, 20h and 30h.
• 11.4 Measurement of rocker cover intake, extraction and blow-by gas volumes
  • 11.4.1 Adjust the rocker cover intake valve so that the extraction volume reaches 850L/h±28L/h, observe and record the rocker cover intake volume, and calculate the standard extraction volume according to formula (1):
    • SLH = ALH × [((BARO + GAS)/101.32kPa) × (294.26K/TEMP)]
    • Where: SLH— standard extraction volume, L/h; ALH— measured extraction volume, L/h; BARO— barometer reading, kPa; GAS— extraction pressure, kPa; TEMP— extraction temperature, K.
  • 11.4.2 Measure the difference between the extraction volume and the intake volume.

7. Sampling and Sample Preparation

• 8 Test oil sample
  • 8.1 Selection: use uncontaminated upper (original text unclear in the source text (source-text extraction))
  • 8.2 Testing: the testing criteria for new oil are detailed in 12.1.1.
  • 8.3 Amount: approximately 8L test oil is required for each test (original text unclear in the source text (source-text extraction)).
• 11.6 Oil sample extraction and addition: extract and add oil samples after 10h, 20h, 30h of the test.
  • 11.6.1 Open the sampling valve and drain 60mL dead volume test oil into a measuring cup.
  • 11.6.2 Drain another 180mL oil sample at the same position.
  • 11.6.3 not provided in the available source (source-text extraction missing)
• 12.1 Oil sample analysis
  • 12.1.1 Determine the kinematic viscosity at 40℃, 100℃ of new oil and 10h oil samples.
  • 12.1.2 For multi-grade oils, determine the SIG capability at test 10h, specific analysis method see Appendix N.

8. Analysis Procedure

• 11.1 Break-in and cleaning: the test has 4h break-in and 0.5h cleaning steps.
  • 11.1.1 Install an oil filter in the oil heater bypass (Figure 6); each break-in requires a new oil filter element with filtration accuracy 28μm.
  • 11.1.2 Add 2840mL test oil before the test, perform engine pre-lubrication (Appendix L).
  • 11.1.3 Perform 4h break-in according to the conditions in Table 1; main oil gallery temperature ≤107.0℃, oil pressure 280kPa±10kPa, coolant outlet temperature ≤93.5℃; record according to the format in Appendix M.
  • 11.1.4 After break-in is completed, stop the engine, immediately move the piston to top dead center (TDC), drain oil 10min; keep the crankcase breather open to the atmosphere.
  • 11.1.5 Connect the oil heater (Figure 7), perform the oil circulation cleaning step.
  • 11.1.6 Add 1660mL test oil for 0.5h cleaning, perform pre-lubrication beforehand.
  • 11.1.7 Cleaning step conditions: speed 3150r/min±25r/min; load 3.73kW±0.15kW; ignition advance angle (BTDC) 35°±1°; main oil gallery temperature ≤107.0℃; coolant outlet temperature ≤93.5℃; oil pressure 280kPa±10kPa; turn off the oil heater switch; record according to Appendix M.
    • 11.1.7.1 The shutdown time between break-in and cleaning conditions must not exceed 4h, emergency shutdowns must not exceed 1 times, total shutdowns must not exceed 2 times.
    • 11.1.7.2 Within the total shutdown time 4h, the time interval must not exceed 85min.
    • 11.1.7.3 After the cleaning step is completed, the shutdown time must not exceed 145min.
  • 11.1.8 Immediately after shutdown, move the piston to TDC, drain oil 10min.
• 11.2 Test operating conditions: operate according to the provisions of Table 2.
  • 11.2.1 Shutdown time during the formal test: within the initial 10h, only 1 shutdowns or 1 emergency shutdowns are allowed, total shutdown time must not exceed 2h; during the 40h formal test, shutdown time must not exceed 6h, emergency shutdowns must not exceed 2 times, total shutdowns must not exceed 4 times.
  • 11.2.2 Warm-up steps: add 1660mL new test oil, pre-lubricate, warm up, adjust speed to 3150r/min; when the main oil gallery temperature is 123.9℃, adjust the heater power to 1900W or set the oil temperature set point to 132.2℃, this step 10min; see Table 3 for details.
• 11.5 Abnormal shutdown
  • 11.5.1 Turn off the oil heater, run the engine under the condition of 1500r/min for 10min; allow the rocker cover to continue venting, turn off the ignition switch to stop the engine; the engine can also be stopped by cutting off the fuel supply, after shutdown move the piston to TDC.
• 11.7 Periodic data recording
  • 11.7.1 Record hourly: engine speed, load, fuel flow, main oil gallery temperature, oil heater regulated power, coolant inlet temperature, coolant outlet temperature, oil pressure, crankcase vacuum, exhaust back pressure, intake air temperature, intake manifold vacuum, crankcase extraction volume, rocker cover air flow, blow-by gas volume (see Appendix M).
  • 11.7.2 Record at 1h, 10h, 20h, 30h: air-fuel ratio, ignition advance angle (BTDC).
• 11.8 Oil draining and oil consumption calculation after the test: after completing the 40h test, turn off the ignition switch to stop the engine, immediately move the piston to TDC to drain oil, ensure the test oil is completely drained; the maximum oil consumption required by the test is 778mL.
• 11.9 Effective operation: ensure the validity of each test operation; operation deviations must meet the specific requirements of 11.1; the bench, test operation, and test unit assembly must be based on the latest available standards.
  • 11.9.1 The percentage deviation is calculated according to formula (2): DP = [(M/0.5R) × (Ti/D) × 100] (the original formula source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction))
    • Where: DP— percentage deviation; M— the deviation value of the parameter from the standard specified value occurring during the test; R— the range value of the test parameter; Ti— the time during which the test parameter deviates from the standard required specified value during the test; D— the test or test stage duration.
  • 11.9.1.1 If the parameter percentage deviation exceeds the following specified values, the test is considered invalid:
    • (a) Main test parameters (2.5%): (1) fuel flow rate; (2) crankcase blow-by rate; (3) main oil gallery temperature; (4) coolant outlet temperature; (5) coolant inlet-outlet temperature difference; (6) oil pressure.
    • (b) Auxiliary test parameters (5.0%): (7) rotational speed; (8) air-fuel ratio; (9) ignition advance angle; (10) exhaust back pressure; (11) crankcase vacuum.
• 11.10 Test end: 40h After the test is completed, confirm the test end within 25min.
• 12.2 Bearing shell weighing: disassemble the engine within 4h after the test ends, weigh the upper and lower bearing shells, in units of mg; if it exceeds 4h, the test is considered invalid. Clean according to the specified method before weighing; the difference in bearing shell weight before and after the test is the test bearing shell weight loss, weighed to an accuracy of 0.1mg.

9. Qualitative and quantitative and calculation formulas

• Standard blow-by rate calculation formula (1): SLH = ALH × [((BARO + GAS)/101.32kPa) × (294.26K/TEMP)]
• Percentage deviation calculation formula (2): DP = [(M/0.5R) × (Ti/D) × 100] (the original formula source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction))
• Bearing shell weight loss: the difference in bearing shell weight before and after the test, accurate to 0.1mg.
• Viscosity grade retention (SIG): according to Appendix N, measure the viscosity of the test oil 100℃ (GB/T 265).

10. Precision

• 14.1 Precision: established from valid test results of reference oils 704-1 and 1006 monitored by ASTM TMC; the measured value is obtained by multiplying the standard deviation by 2.8; the standard deviation is shown in Table 4.
• 14.1.1 Repeatability (IP): for 2 results obtained from the same oil sample in the same laboratory, the difference between 2 repeatability test results may exceed the value in Table 4 only 1 times in 20 tests.
• 14.1.2 Reproducibility (R): for 2 results obtained from the same sample in different laboratories, the difference between 2 test results may exceed the value in Table 4 only 1 times in 20 tests.
• 14.2 Bias: determine the bias by processing reference oil test results with recognized statistical methods; once the valid bias is determined, the severity of non-reference oil test results can be corrected.

Table 4 Reference oil test precision

In the table: SIP— repeatability standard deviation; IP— repeatability; SR— reproducibility standard deviation; R— reproducibility.

11. Report

• 13.1 For reference oil tests, the test results and operating conditions require standard report and record forms.
• Appendix M (normative appendix) Procedure VII test record form: recorded items include time, oil, oil pressure, air-fuel ratio, blow-by rate, etc. (the original table source-text extraction is incomplete, requires confirmation against the source standard (source-text extraction)).

12. Referenced documents

• GB/T 259 Petroleum products — Determination of water-soluble acids and alkalis
• GB/T 265 Petroleum products — Determination of kinematic viscosity and calculation of dynamic viscosity
• GB/T 380 Petroleum products — Determination of sulfur content (lamp method)
• GB/T 1792 Determination of mercaptan sulfur in distillate fuels (potentiometric titration method)
• GB/T 1884 Laboratory determination of density of crude petroleum and liquid petroleum products (hydrometer method) (GB/T 1884-2000, eqv ISO 3675:1998)
• GB/T 1885 Petroleum measurement conversion tables (GB/T 1885—1998, eqv ISO 91-2:1991)
• GB/T 5096 Petroleum products — Copper strip corrosion test
• GB/T 5487 Determination of gasoline octane number (research method)
• GB/T 6536 Petroleum products — Determination of distillation
• GB/T 8017 Petroleum products — Determination of vapor pressure (Reid method)
• GB/T 8018 Determination of oxidation stability of gasoline (induction period method)
• GB/T 8019 Determination of existent gum in automotive gasoline and aviation fuels (jet evaporation method) (GB/T 8019—1987, mod ISO 6246:1981)
• 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)
• GB/T 15890 Petroleum ether
• SH 0004 Solvent naphtha for rubber industry
• SH/T 0174 Qualitative test for mercaptans in aromatic hydrocarbons and light petroleum products (Doctor test method) (SH/T 0174—1992, eqv ISO 5275:1979)
• SH/T 0663 Determination of certain alcohols and ethers in gasoline (gas chromatography)

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