SH/T 0757-2005 Evaluation Method for Fuel Economy Performance of Internal Combustion Engine Oils (Procedure VI 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.

Incomplete source card: Sections 9, 10, 11, 12, 13, 14 are absent from the available source. Only available content is translated; source completion is pending.

Card type: Test method

1. Method Number / Full Title / English Name / Supersession Relationship

• Standard number: SH/T 0757-2005
• Chinese title: Evaluation Method for Fuel Economy Performance of Internal Combustion Engine Oils (Procedure VI Method)
• English title: Standard dynamometer test method for measuring the energy conserving quality of engine oils
• Supersession relationship: not provided in the available source (the foreword only states modified adoption of the ASTM working group document, and does not mention superseding an old standard number)
• Adoption relationship: modified adoption of the American Society for Testing and Materials ASTM working group document "Evaluation Method for Fuel Economy Performance of Internal Combustion Engine Oils (Procedure VI Method)"
• Publication/implementation: published on 2005-04-11, implemented on 2005-09-01
• Issuing authority: National Development and Reform Commission of the People's Republic of China
• Technical committee: Sinopec Research Institute of Petroleum Processing
• Drafting organization: Sinopec Research Institute of Petroleum Processing
• Main drafters: Wang Qingxin, Yang Benfeng, Liu Shuntao, Wang Dianfu, Lu Wentong
• Appendix attributes: Appendix A and Appendix C are normative appendices, Appendix B is an informative appendix

2. Scope of Application and Non-Applicability

• 1.1 This standard specifies a method for evaluating the effect of internal combustion engine oils on the fuel economy of passenger cars and light trucks.
• 1.2 This standard is applicable to evaluating the energy-saving performance of internal combustion engine oils (for example: ILSAC GF-1).
• Non-applicability: no explicit non-applicability clause is provided in the available source.

3. Method Principle

• Chapter 4 Method summary: A 3.8L Buick V-6 dual-chamber carburetor engine produced in 1982, 1986, or 1987 is used for the test. During the test, the engine is operated under three specified conditions, and the technique of changing the internal combustion engine oil without stopping the engine is used to determine the fuel consumption rate under each condition. The fuel consumption rate of the test oil is directly compared with the fuel consumption rate of the 20W/30 SE grade reference oil (HR oil) specified in ASTM. The test results are expressed as the percentage change in brake-specific fuel consumption (BSFC) relative to the reference oil.
• 5.1 Function: The data obtained from this method are comparative data on the fuel-saving capability of internal combustion engine oils under repeated laboratory test conditions. This method has higher resolution and precision than the ASTM "five-car test" method it replaces. HR oil provides the comparison baseline for all tests; HR oil is a fully formulated SAE 20W/30 oil that meets the SE grade gasoline engine oil specification; its fuel economy performance is close to the intermediate value between 10W/30 SE grade and 10W/40 SE grade commercial oils produced in 1978.
• 5.2 Correlation with the "five-car test": When this test method was developed, its correlation with the ASTM "five-car test" was specifically studied; the relationship between the two is shown in Figure 1 (original Figure 1).
• 5.3 Validity of the test: It depends on the degree of compliance with all requirements of this test method; during the test, recorded data must be checked periodically to promptly discover and correctly handle instrument and meter faults. Parameters that have a relatively large impact on test results: stability of test conditions; stability of air-fuel ratio; stability of fuel flow; intake manifold vacuum. Only tests conducted on a bench that has been calibrated and qualified with calibration oils can possibly be valid tests.
• 5.4 Use: It can be used for product specifications of internal combustion engine oils; in research work on energy-saving formulations of internal combustion engine oils, it can also be used to evaluate and compare energy-saving levels.

4. Reagents and Materials (Purity / Preparation)

7.1 Test Fuel

The fuel used must meet the technical requirements in Table 1.

Table 1 Technical Requirements for Test Fuel

7.2 Reference Oils

• 7.2.1 Baseline reference oil (HR): a SE grade oil specially for 20W/30 testing; it is the main reference oil for evaluating test oils and is also used to determine stability during engine break-in. Approximately 38L is required per test.
• 7.2.2 High-viscosity reference oil (LR): viscosity grade SAE 50, with the same additives as HR oil. During the calibration stage of the test, LR oil is used to compare with HR oil to determine the change in fuel consumption rate of the test engine when the oil viscosity changes. Approximately 19L is required per test.
• 7.2.3 Friction-modifier reference oil (FM): prepared by blending HR oil with a molybdenum-amine type friction modifier; this friction modifier acts relatively quickly but has a relatively short duration. This oil is used to calibrate the sensitivity of the test engine to friction modifiers, and approximately 19L is required per test.
• 7.2.4 Flush oil (FO): prepared by blending HR oil with a high-concentration detergent. When the engine is to be changed from FM oil or test oil after testing, the engine must be flushed with FO oil to remove the effects of FM oil or test oil. Approximately 38L flush oil is required per test.

7.3 Engine Coolant

Prepared by blending antifreeze and water in a ratio of 1:1 (volume fraction); the water used must be deionized water or distilled water.

7.4 Cleaning Materials

• 7.4.1 Carburetor cleaner: commercially available carburetor cleaner.
• 7.4.2 Engine cooling system cleaner: Dupont heavy-duty vehicle cooling system cleaner or equivalent product, which includes components such as oxalic acid, petroleum dispersant 425# (Petro Dispersant Number 425 Powder), and sodium carbonate.

7.5 Engine Fill Oil

HR oil or EF-411 oil (EF-411 oil is a base oil containing no additives).

8 Test Oil

At least 19L is required per test, but generally 38L test oil should be provided. The kinematic viscosity at 40℃ and 100℃ of the new oil must be determined.

5. Instruments and Equipment

6.1 Laboratory Environmental Conditions

• 6.1.1 Engine operating room: dirt, dust, and other contaminants in the laboratory atmosphere should be minimized. The air supply system should avoid blowing directly on the test engine.
• 6.1.2 Assembly room and measurement room: It is recommended that the air in the assembly room and measurement room be filtered and maintained at uniform temperature and humidity to prevent dust from accumulating on parts or causing parts to rust.
• 6.1.3 Parts cleaning room: Because solvents are used when cleaning parts, the cleaning room must be ventilated.

6.2 Test Bench and Laboratory Equipment

• 6.2.1 Test bench: The carburetor mounting flange of the engine intake manifold should be horizontal. Select a suitable engine mount so that vibration is minimized when operating at 1500r/min.
• 6.2.2 Engine speed and load control system: It should be able to meet the test conditions specified in this standard; within the measurement interval from 100s to 120s, the control accuracy of the average speed is ±2r/min, and the control accuracy of the average load is ±0.07N·m. In all cases, the measurement and calculation of brake-specific fuel consumption must be coordinated with the measurement of each parameter; in particular, the displayed values of speed, load, fuel flow, and CO content in the exhaust are average values during the measurement period from 100s to 120s, so it is necessary to ensure that measurement lag factors are minimized.
• 6.2.3 Carburetor air supply system: The air supply flow rate is approximately 63.8L/s; the air temperature, pressure, and humidity to the carburetor must meet the test conditions.
• 6.2.4 Exhaust system
  • 6.2.4.1 Exhaust manifold: A dedicated water-cooled exhaust manifold must be used.
  • 6.2.4.2 Exhaust surge tank: Use the exhaust surge tank dedicated to the Procedure VI test; the distance from the exhaust manifold outlet flange to the exhaust surge tank inlet flange is 203mm±101mm.
  • 6.2.4.3 Exhaust back pressure sensor: installed at the middle of the side wall of the exhaust surge tank.
  • 6.2.4.4 Exhaust analysis: The CO content in the exhaust must be accurately determined. It is recommended to use a non-dispersive infrared spectrometer to determine the CO content and a polarograph to determine the O₂ content; the analytical instruments must have the capability for continuous measurement of 30min. An excessively long line between the exhaust sampling port and the analyzer will increase potential errors; therefore, the sampling line should be as short as possible.
• 6.2.5 Fuel supply system
  • 6.2.5.1 Fuel supply pressure: The fuel supply pressure must be stable and controlled within the range required by this standard; the stability of the fuel supply is critical to test precision. It is recommended to adjust the pressure in two stages. Assume the fuel pressure in the main fuel supply line is 138kPa–207kPa(20psi–30psi); the first-stage pressure can be adjusted to about 89.6kPa(13psi), and then the pressure of the second-stage pressure regulator installed in the 3m before the carburetor fuel inlet must be adjusted to within the range of 41.4kPa–62.1kPa(6psi–9psi) (test phase). During the cyclic phase of engine break-in, the fuel pressure must be adjusted to 27.6kPa(4.0psi).
  • 6.2.5.2 Fuel flow measurement: The accuracy of fuel flow measurement is critical; therefore, a fuel consumption measuring device with an accuracy of ±0.20% must be selected.
  • 6.2.5.3 Fuel temperature control system: A suitable system must be used to control the fuel temperature within the range required by this standard.
• 6.2.6 Engine cooling system: As shown in Figure 2. This system has the following features:
  • a) Closed cooling system; the cooling tank is equipped with a cap capable of releasing a pressure of 34.5kPa~69.0kPa.
  • b) The coolant pump flow rate can reach 1.89L/s±0.06L/s.
  • c) There is a device for controlling and measuring the coolant pump flow rate; the minimum accuracy of the flow meter is ±1%.
  • d) Before new coolant is added, it must be possible to drain all flushing water (that is, a low-point drain valve is provided).
  • e) There is a sight glass near the engine coolant outlet to check for bubbles in the liquid flow.
• 6.2.7 External oil circulation system: As shown in Figure 3. This system consists of two parts: one is a flushing system for changing oil without stopping the engine, and the other is an oil temperature control system.
• 6.2.8 Installation positions of thermocouples
  • 6.2.8.1 Engine coolant inlet: The distance from the temperature measuring point to the inlet flange is not greater than 76mm, and the temperature measuring point is inserted at the center of the liquid flow.
  • 6.2.8.2 Engine coolant outlet: The distance from the temperature measuring point to the outlet flange is not greater than 76mm, and the temperature measuring point is inserted at the center of the liquid flow.
  • 6.2.8.3 Engine main oil gallery: The thermocouple is installed at the oil gallery hole at the right front of the engine and inserted into the engine block.
  • 6.2.8.4 Oil pan: The thermocouple is installed in the external oil circulation system, and the distance from the oil pan is kept within 51mm.
  • 6.2.8.5 Fuel temperature: The thermocouple is installed at a distance of 152mm from the carburetor inlet.
• 6.2.9 Pressure measuring equipment
  • 6.2.9.1 Intake manifold vacuum (absolute pressure): Use a sensor with an accuracy of 1% and a resolution of 0.68kPa, installed behind the carburetor.
  • 6.2.9.2 Oil pressure: Use a sensor with an accuracy of 1% and a resolution of 6.9kPa, installed on the main oil gallery.
  • 6.2.9.3 Carburetor fuel pressure: Use a sensor with an accuracy of 3.5kPa, installed at the carburetor fuel inlet.
  • 6.2.9.4 Carburetor intake pressure: Use a sensor with an accuracy of 2% and a resolution of 49.8Pa, installed at the carburetor intake port.
  • 6.2.9.5 Crankcase pressure: Use a sensor with an accuracy of 2% and a resolution of 49.8Pa, installed at the original fuel pump mounting plate of the crankcase.
  • 6.2.9.6 Exhaust back pressure: Install a specially made sampling tube in the middle of the exhaust pressure stabilizing tank; the sensor used has an accuracy of 2% and a resolution of 24.9Pa. A suitable condensate collector is installed between the sensor and the sampling tube to collect condensed water in the exhaust gas.
• 6.2.10 Crankcase ventilation system: At the connection where the PCV valve was originally installed on the intake manifold, it directly opens to the atmosphere. The rocker arm cover is not ventilated.
• 6.2.11 Oil flushing system: During engine operation, the oil flushing system should be able to change the oil as required. It generally includes an external oil tank, a solenoid valve, and an oil change amount measuring device. A schematic diagram of its components and flow is shown in Figure 3.

6.3 Test engine

Use a 3.8L Buick V-6 two-barrel carburetor engine produced in 1982, 1986, or 1987. The engine must be assembled in accordance with this standard (see clause 9.2). During assembly, it is recommended to use an old cylinder block. If a new cylinder block is used, it must be run for at least 8h under light load conditions, then disassembled and reassembled; this makes the dimensions of the cylinder block more stable. This standard requires two types of carburetors, namely a break-in carburetor and a test carburetor. These two carburetors, as well as the intake bellmouth, oil pan, rocker arm cover, distributor, and intake manifold, etc., all need to be modified.

6.4 Special measuring and assembly equipment

• 6.4.1 Cylinder block pre-stress plates: Two special honing pre-stress plates are required. During cylinder honing, the pre-stress plates are fastened to the cylinder block with special bolts and shims.
• 6.4.2 Cylinder honing equipment: Use a Sunnen CK-10 or equivalent honing machine.
• 6.4.3 Cylinder surface roughness measuring instrument: After cylinder honing, a surface measuring instrument must be used to measure its roughness; the acceptable range is 0.31μm~0.41μm.
• 6.4.4 Engine pre-lubrication equipment: Before starting the engine, the oil pump must be turned with a hand drill for 1min~2min to fill the oil galleries, cooler, and other oil system components with oil.

6. Recommended operating conditions

Table 7 Test conditions

Note: Parameters marked with "*" in Table 7 should be controlled as close as possible to the middle value of the specified range. The specific parameter values for the 135 condition and the 65.6 condition in Table 7 cannot be fully identified due to source-text extraction noise and require confirmation against the source standard (source-text extraction).

Table 5 New engine cyclic break-in operating conditions

Table 4 Engine idle operating conditions

7. Sampling and specimen preparation

• Chapter 8 Test oil: Each test requires at least 19L, but generally 38L of test oil should be provided. The kinematic viscosity of the new oil at 40℃ and 100℃ must be measured.
• 9.1 Preparation of the test bench
  • 9.1.1 Cleaning of the external oil system: A newly assembled engine must be thoroughly cleaned of the external oil system with solvent naphtha.
  • 9.1.2 Replacement of the exhaust sampling tube: Before testing, check whether the sampling tube is normal and whether the gas holes are blocked. When the sampling tube is found to be broken or deformed, it must be replaced.
  • 9.1.3 Replacement of hoses: Check all coolant connection hoses; if damaged or if the inner wall hinders liquid flow, they should be replaced.
• 9.2 Engine assembly: Since this test requires an engine with very stable operation, special care and attention to every assembly detail are required when assembling the engine. It is recommended to use an old cylinder block because an old cylinder block is more dimensionally stable than a new one. It is best to use a cylinder block that has previously been used for a Procedure IIE test. If a new engine is used, it should be run under light load for at least 8h, then disassembled, and the engine reassembled as required by this method.
  • 9.2.1 Cleaning of parts
    • 9.2.1.1 Disassemble the engine: Completely disassemble the engine, including all machining plugs and main oil gallery plugs.
    • 9.2.1.2 Soaking: Soak all parts and the cylinder block in a degreasing solvent until clean; during the first cleaning, solvent is allowed to enter the cylinder block cooling jacket.
    • 9.2.1.3 Cleaning: Thoroughly clean the part surfaces with hot water and flush the cylinder block oil galleries and water passages.
    • 9.2.1.4 Protection: After hot water cleaning, thoroughly spray-wash all parts with a Stoddard solvent (or 149℃~204℃ solvent naphtha) containing 10% (volume fraction) HR oil, being careful not to spray solvent into the cooling jacket.
    • 9.2.1.5 Treatment of cylinder block and cylinder liners: After cylinder honing, measurement, and piston ring end gap machining are completed, scrub the cylinder walls with a brush and hot detergent water. Then spray-wash the cylinder block with cleaning solvent, blow dry all oil galleries with compressed air, and finally wipe the cylinder walls with a soft cloth and HR oil.
  • 9.2.2 Engine assembly instructions: According to the production year of the cylinder block used (1982, 1986, or 1987), assemble strictly in accordance with the Buick engine service manual for the corresponding year and the detailed engine assembly instructions of the "Test Method for Evaluating High-Temperature Oxidation and Anti-Wear Performance of Internal Combustion Engine Oils (Procedure IIIE Method)"; if this method provides additional detailed instructions, follow the instructions of this method. During engine assembly, coat part surfaces with HR oil or EF411 oil.
    • 9.2.2.1 Special parts: The intake manifold, distributor, fuel pump mounting plate, oil pump cover, rocker arm cover, oil pan, carburetor, and carburetor air horn, etc., must all use modified special parts. Except for the above parts, other parts must use new parts consistent with the production year of the cylinder block.
    • 9.2.2.2 Installation dimensions: See Table 2.

Table 2 Engine installation dimensions

- 9.2.2.3 Bolt tightening torque: Before installation, bolts must be cleaned thoroughly and coated with HR oil or EF411 oil; the bolt tightening torques are shown in Table 3.

Table 3 Bolt tightening torque

8. Analysis procedure

10 Break-in of a new engine

• 10.1 Preparation before new engine break-in
  • 10.1.1 Preparation before adding oil: Carefully inspect the equipment to ensure that all lines and fittings are properly installed; remove the oil line connecting the oil pan and the valves (valves N/O and N/C in Figure 3), remove residual oil from it, and then reinstall this section of oil line.
  • 10.1.2 Adding oil: Install a new oil filter and add 5.7L of HR oil to the engine.
  • 10.1.3 Prelubrication: Using a hand electric drill and a distributor connector, rotate the oil pump clockwise at the distributor installation location for 1min~2min.
  • 10.1.4 Install the distributor: After prelubrication is completed, install the modified distributor. Set the ignition timing to approximately 40° before top dead center.
  • 10.1.5 Add cooling system cleaning solution: Close the small valves on both sides of the coolant flowmeter to prevent the cleaning solution from contaminating the flowmeter. Add the cleaning solution prepared in proportion (for each liter of water, add 23g oxalic acid and 1g petroleum dispersant) to the cooling system.
  • 10.1.6 Install the carburetor: Install the modified break-in carburetor.
  • 10.1.7 Adjust fuel pressure: Adjust the fuel pressure to approximately 27.6kPa.
• 10.2 Inspection and adjustment after starting the engine
  • 10.2.1 Adjust ignition timing: Start the engine; when the engine is idling (1000r/min, no load), check for leaks and adjust the ignition timing to 40° before top dead center.
  • 10.2.2 Adjust oil pressure:
    • a) After adjusting the ignition timing, set the engine to the operating conditions shown in Table 4.
    • b) After the engine reaches the above operating conditions, disconnect the oil filter (cut off the bypass valve).
    • c) Operate the engine stably under the 107.2 condition (see Table 7).
    • d) Adjust the engine main oil gallery pressure to 276kPa±3.5kPa.
    • e) Alternately change speed (1500r/min-1600r/min-1500r/min) and load to ensure that the oil pressure can return to 276kPa±3.5kPa.
    • f) After oil pressure adjustment is completed, connect the oil filter into the system (open the bypass valve).
• 10.3 Cooling system flushing
  • a) After the engine has run under the above conditions (Table 7) for 40min, open the small valve on the side of the engine block and the drain valve below the coolant heat exchanger, while adding tap water to the system until the discharged water is clean. Continue adding tap water to the system for 5min, then close the small valve on the side of the block and the heat exchanger drain valve. Then add a pre-prepared sodium carbonate aqueous solution (solution concentration of approximately 3.8g sodium carbonate per liter of hot water).
  • b) After the engine has run for 25min, open the drain valve while adding tap water until the discharged water is clean (the pH values of inlet and outlet water are the same). Close the inlet and drain valves and operate the engine under the conditions specified in Table 4 for 20min.
  • c) Operate the engine at idle; when the main oil gallery oil temperature reaches 49℃, stop the engine using the procedure described in clause 12.2.1. If the carburetor is connected to an intake control system, immediately disconnect the air supply line after shutdown.
  • d) After shutdown, immediately shut off fuel and ignition, drain the fuel from the carburetor, fully open the throttle and remove all spark plugs, and measure the compression pressure of each cylinder one by one. Record the compression pressure of each cylinder when the engine is being cranked at 200r/min±2r/min. The pressure difference among cylinders must not exceed 69kPa. Otherwise, disassemble and reassemble the engine, taking care during this period to protect the valves and piston ring assemblies.
  • e) Drain the cooling system.
  • f) Add test coolant to the cooling system, consisting of 1:1 (volume fraction) ethylene glycol antifreeze and distilled water. The added coolant may be reused.
• 10.4 New engine break-in
  • 10.4.1 Adding oil: After completing the compression pressure check, remove the old oil filter and install a new oil filter. After draining the oil, add HR of new 5.7L oil to the engine.
  • 10.4.2 Cyclic operation stage of break-in: Break in the new engine for 88h according to the cyclic operating conditions specified in Table 5, record the operating conditions of the A stage and the fuel specific fuel consumption (BSFC) once per hour, and observe the trend of change in BSFC; the calculation of BSFC is given in formula (1).
  • 10.4.3 Stable operation stage of break-in: After the break-in cyclic stage is completed, operate the engine for 12h under the 107.2 condition (see Table 7), and record operating data once every half hour. Before the stable operation stage, the following work must be completed:
    • a) Disconnect the oil filter.
    • b) Remove the break-in carburetor and install the test carburetor.
    • c) Adjust the fuel pressure to 41.4kPa~62.1kPa.
    • d) Confirm that the oil pressure is 276kPa.
  • 10.4.4 Calibration stage after break-in: After the data from the stable stage meet the requirements (see clause 10.4.6.1), the calibration stage of break-in may be carried out (the calibration procedure is shown in the "Calibration stage" in Table 8). If the calibration is not qualified (for qualification criteria see clauses 10.4.6.2, 10.4.6.3, 10.4.6.4, and 10.4.6.5), recalibrate until qualified.
  • 10.4.5 Handling of oil consumption during the break-in stage: The oil level in the oil pan must not be lower than 118.3mL below the "full mark" (the scale on the oil pan sight window may be observed). During the cyclic stage of break-in, HR oil may be added, and the amount added must be recorded; during the stable stage of break-in, oil must not be added.
  • 10.4.6 Criteria for completing break-in: When the following criteria are met, the break-in of the new engine may be ended.
    • 10.4.6.1 BSFC difference rate: The difference rate of all BSFC measured during the 12h stable stage of break-in is not greater than 1%, calculated according to formula (1).
    • 10.4.6.2 Energy-saving rate of the high-viscosity reference oil: In the calibration stage, the energy-saving rate of LR oil compared with HR oil under the 65.6 condition (see Table 7) should be -4.5%~-8.5%, calculated according to formula (2).
    • 10.4.6.3 Energy-saving rate of the friction-reducing reference oil: during the calibration stage, the energy-saving rate of FM oil under 135 operating conditions (see Table 7) compared with HR oil under 65.6 operating conditions should be 8.0%~11.0%, and the energy-saving rate of FM oil under 135 operating conditions compared with HR oil under 135 operating conditions should be 7.0%~11.0%, calculated according to formula (3), formula (4).
    • 10.4.6.4 Effect of oil temperature of HR oil on fuel consumption: report the energy-saving rate of HR oil under 107.2 operating conditions and 135 operating conditions compared with 65.6 operating conditions, with no specified range.
    • 10.4.6.5 Main operating parameters: during the calibration stage, during each set (6 times) of measurements (5min once) of FM135, HR135 and HR65.6 at BSFC, the average values of the 6 data of the corresponding main parameters (speed, load, CO content in exhaust, exhaust back pressure, coolant temperature and main oil gallery temperature) must also meet the requirements of this method, otherwise the test is invalid.
    • 10.4.6.6 Handling when run-in is unqualified: if after run-in it does not meet the requirements of clause 10.4.6, any of the following measures shall be adopted until the run-in meets the requirements.
      • a) Re-run the cyclic stage of run-in.
      • b) Re-run the stabilization stage of run-in.
      • c) Re-run the calibration stage.
      • d) Reassemble the engine.

11 Engine calibration

After completing the run-in of a new engine, or before each test, the engine must be calibrated. The purpose of engine calibration is to verify the sensitivity of the engine to changes in the boundary friction characteristics and viscous resistance of the lubricating oil, and additionally:

• a) Check whether the engine run-in is qualified.

• b) Check whether the engine is suitable for test oil testing.

• 11.1 Reference oils for calibration: a) high-viscosity reference oil (LR); b) friction-reducing reference oil (FM); c) baseline reference oil (HR); d) flush oil (FO). After completing the run-in of a new engine, or after each test is completed, the lubricating oil in the engine should be HR oil, to be ready for the next calibration.

• 11.2 Engine calibration procedure: see "calibration stage" in Table 8.

• 11.3 Engine calibration acceptance criteria: adopt the criteria specified in clauses 10.4.6.2~10.4.6.5.

• 11.4 Measures to be taken when engine calibration is unqualified:

  • a) If the engine run-in is suspected to be unqualified, re-run the run-in.
  • b) If the LR oil or FM oil in the test is suspected of chemical contamination, flush with FO oil or extend the operating time of HR oil and re-calibrate.
  • c) Disassemble the engine and reassemble it.

12 Test procedure

• 12.1 Carburetor: install a modified test carburetor. Under the 107.2 operating condition of the test and during the flush oil change stage (fuel pressure 41.4kPa~62.1kPa), the carburetor must meet the following requirements:
  • a) When the engine is running, observe the venturi with a strobe light; no fuel should flow out.
  • b) When the engine is operated under 2000r/min and 8.1N·m conditions, there must be no misfire or detonation due to lean mixture; otherwise, adjust the idle oil hole adjusting screw (turn counterclockwise to enrich the mixture).
• 12.2 Method for starting and stopping the engine
  • 12.2.1 Normal method for starting and stopping the engine: turn off the electronically controlled air-fuel ratio adjustment device, and the engine can be started by cranking. For normal shutdown, cut off the fuel and let the engine run under 1500r/min or idle conditions until the fuel in the carburetor is exhausted. Whenever the engine is stopped, disconnect the carburetor intake line as soon as possible.
  • 12.2.2 Restart after abnormal shutdown: if an abnormal shutdown occurs, handle it as specified in Table 6.

Table 6 Handling method for restart after abnormal shutdown

• 12.3 Flush oil change procedure using flush oil (FO): when changing from FM oil or test oil to HR oil, use FO oil for intermediate flushing to eliminate the influence of residual FM oil or test oil on the HR oil test results. The steps are as follows:
  • a) Heat the FO oil and HR oil in the external oil tank to 93.3℃~107.2℃.
  • b) Operate the engine under 2000r/min, 8.1N·m and other conditions of 107.2 operating conditions.
  • c)