GB/T 9933-1988 Performance evaluation of internal combustion engine oils (Caterpillar 1G2 method)

Summary page. This page is a compiled excerpt/summary of the standard — it is not the full standard text and does not replace it. Verify every value against the official standard and the product certificate before use.

GB/T 9933-1988 specifies the Caterpillar 1G2 method for evaluating the detergency and antiwear performance of internal combustion engine oils, including the test engine and bench configuration, fuel specification, break-in and operating conditions, piston deposit rating and precision.

Evidence note: the content of this page was compiled from the original text of this standard held in the Origin Standard library (points marked "[to be verified]" are "[source unclear]" in the original); for individual values and current status, refer to the original pages of the standard and the product certificate.

Scope: This standard specifies the Caterpillar 1G2 method for evaluating the detergency and antiwear performance of internal combustion engine oils. It applies to the performance evaluation of diesel engine oils (CD grade), and also to the performance evaluation of oils for both gasoline and diesel engines, oils for diesel locomotives, and similar oils. Not applicable: not provided in the available material. Validity statement: only tests carried out strictly in accordance with this method are valid.

Principle: Before each test, the power-producing parts of the engine shall be completely disassembled, cleaned with solvent, measured, and reassembled strictly in accordance with the technical requirements. New pistons, piston rings and cylinder liners shall be installed for each test. The engine crankcase is cleaned with solvent, and worn and damaged parts are replaced. The test bench shall have auxiliary equipment for controlling speed, load and the various test conditions, and must be equipped with an engine intake air boosting system capable of heating the air. The test uses the test oil as lubricant. After a 1 h break-in run, the supercharged single-cylinder engine is run for 480 h at the specified speed and fuel consumption rate. One intermediate inspection may be carried out between 96 h and 384 h of testing. For tests with the reference oil, an intermediate inspection must be carried out at 120 h. After the test, the engine is inspected and the nature and quantity of piston deposits, the condition of piston ring sticking, and the extent of wear of piston rings and cylinder liners are determined.

Apparatus: Test engine and auxiliary equipment (4.1): a special supercharged single-cylinder diesel engine, cylinder bore 130.2 mm, piston stroke 165 mm. 4.1.1 Circulating cooling system with a centrifugal water pump driven by the test engine. 4.1.2 Suitable fuel supply system. 4.1.3 Intake air boosting system with a surge tank, intake air heating and intake air humidity control. 4.1.4 Exhaust system with a surge tank and silencer. 4.1.5 Suitable dynamometer to be selected. 4.1.6 Starting motor: torque 372 N·m at 400 r/min, automatically disengaging when the torque increases to 420 N·m. 4.1.7 Crankcase blow-by meter. 4.1.8 Thermocouples for measuring temperatures at the various points. Cooling system (4.2): the coolant circulating flow shall be adjusted to 58±3.8 L/min (15.3±1.0 US gal/min); the flowmeter shall be calibrated on the bench; the coolant is distilled or softened water with a rust inhibitor added. Fuel system (4.3): the length of the line from the fuel filter to the injection pump is 1073±13 mm (42.25±0.5 in), to ensure that the pressure in the fuel line is within the range 137.9±13.8 kPa (20±2 lbf/in²); the measuring accuracy of the fuel consumption meter is within ±3%. Intake system (4.4): fitted with a dry air filter; intake surge tank volume 0.198–0.227 m³ (7–8 ft³), internal diameter 487–584 mm (19–23 in); the length of the line from the outlet flange face of the surge tank to the intake port face of the cylinder head is 794±13 mm (31.25±0.50 in), with only one bend of not less than 90° permitted; the surge tank and electric heater are inspected once a year; the intake air humidity is controlled at 181.7 g of water per kilogram of dry air (125±12 gr/lb), and the humidity measuring system is calibrated every six months. Exhaust system (4.5): the diameter and length of the exhaust pipe downstream of the exhaust manifold elbow are selected so as to obtain an air-fuel ratio of 23.5:1; fitted with an exhaust surge tank and silencer; exhaust back pressure 1.2–3.0 kPa (5–12 inH₂O); 90° elbows should be avoided, and the distance between two elbows should be greater than 305 mm (12 in). Blow-by meter (4.6): a volumetric gas flowmeter fitted with an oil-gas separator and surge tank, connected by hose to the crankcase breather outlet during measurement. Thermocouples (4.7): the temperature at each point is measured with a thermocouple of suitable temperature range. Instrument calibration (6.2.3): thermocouples, pressure gauges, fuel consumption meters, coolant flow, etc. shall be calibrated at least twice a year; secondary instruments shall be checked at least twice a year; the fuel consumption meter shall be calibrated as a whole on the bench.

Reagents and reference materials: Fuel: about 4548 L (1200 US gal) is required per test, specification requirements see Annex A (supplementary); the heat input shall be converted to fuel consumption on the basis of the lower calorific value of the fuel. Test oil: about 76–95 L (20–25 US gal) is required per test. Engine coolant: 1.5% (by volume) RB emulsifying rust-preventive oil added to softened water; fresh coolant must be used for each test. Cleaning agents: Engine cleaning agent: NY-190 solvent naphtha conforming to GB 1922; the cleaning dispersant is petroleum calcium sulfonate (T101). Cooling system cleaning agent: an appropriate amount of industrial sodium sulfate (Na₂SO₄) and industrial sodium phosphate (Na₃PO₄) added to softened water. Annex A Fuel specification (supplementary): | Property | Limit | Test method | |---|---|---| | Flash point, °C, min. | 38 | GB 261 | | Pour point, °C, max. | −7 | GB 3535 | | Cloud point, °C | Report | SY 2204 | | Water and sediment, % (V/V), max. | 0.05 | GB 6533 | | Carbon residue in 10% residue, % (m/m), max. | 0.20 | ZB E 30001 | | Ash, %, max. | 0.01 | GB 508 | | Distillation, °C: initial boiling point | Report | GB 6536 | | Distillation, °C: 10% evaporated temperature | Report | GB 6536 | | Distillation, °C: 50% evaporated temperature | 260–277 | GB 6536 | | Distillation, °C: 90% evaporated temperature | 304–327 | GB 6536 | | Distillation, °C: final boiling point | 343–366 | GB 6536 | | Kinematic viscosity (40 °C), mm²/s | 3.0–4.0 | GB 265 | | Sulfur content, % (m/m) (natural sulfur required) | 0.37–0.43 | GB 380 | | Copper strip corrosion, grade, max. | 2 | GB 5096 | | Neutralization value, mgKOH/g, max. | 0.15 | GB 4945 | | Cetane number | 45–51 | GB 386 | | Density (20 °C), kg/m³ | 846–862 | GB 1884 or GB 1885 | | Cracked material | None | — | Note: some of the above values were [source unclear] in the original (such as "10% residual crab", "natural bowl", "sixteen burn value") and have been corrected according to the context, [to be verified] ([source unclear]).

Key conditions: Break-in schedule (Table 1): add 5.7 L of test oil, run for 1 h according to the steps listed in Table 1, stop the engine and drain the test oil; measure and record the crankcase blow-by during the last 15 min of step 5. Table 1 Engine break-in schedule ([source unclear] table, some values [to be verified]): | Step | Speed, r/min | Load, kW | Heat input | Oil temperature | Coolant outlet temperature | Intake air temperature | Intake air pressure (absolute) | Time, min | |---|---|---|---|---|---|---|---|---| | 1 | 1000±10 | 0 | — | 71.1±2.8 °C (160±5 °F) | 158.6 °F (23 °C) | Ambient | 118.1±1.7 kPa (35±0.5 inHg) | 5 | | 2 | 1000±10 | 7.5 | 56.1±0.9 kW (3192±47 Btu/min) | 71.1±2.8 °C (160±5 °F) | 158.6 °F (23 °C) | Ambient | 118.1±1.7 kPa (35±0.5 inHg) | 5 | | 3 | 1600±10 | 17.1 | — | 71.1±2.8 °C (160±5 °F) | 158.6 °F (23 °C) | Ambient | 135.0±1.7 kPa (40±0.5 inHg) | 10 | | 4 | 1800±10 | 24.6 | 81.7±0.9 kW (4647±47 Btu/min) | 82.2±2.8 °C (180±5 °F) | 98.1±2.8 °C (205±5 °F); piston cooling oil pressure 165.5 kPa (24 lbf/in²) | 76.7±2.8 °C (170±5 °F) | 135.0±1.7 kPa (40±0.5 inHg) | 20 | | 5 | 1800±10 | 31.3 | 96.5±0.9 kW (5491±47 Btu/min) | 96.5±0.9 °C (205±5 °F) | 87.8±2.8 °C (190±5 °F); piston cooling oil pressure 165.5 kPa (24 lbf/in²) | 123.9±2.8 °C (255±5 °F) | 178.9±1.7 kPa (53±0.5 inHg) | According to the cool-down step in 8.6 | Note: some temperature/pressure values in Table 1 are [source unclear] with misalignment and noise, [to be verified] ([source unclear]). Formal test conditions (Table 2): | Parameter | Value | |---|---| | Speed | 1800±10 r/min | | Heat input | 96.5±0.9 kW (5490±47 Btu/min) (engine output power approximately 31.3±1.5 kW at this fuel consumption rate) | | Coolant outlet temperature | 87.8±2.8 °C (190±5 °F) | | Coolant flow | 58.0±3.8 L/min (15.3±1.0 US gal/min) | | Oil temperature | 96.1±2.8 °C (205±5 °F) | | Intake air temperature | 123.9±2.8 °C (255±5 °F) | | Exhaust temperature | 593±28 °C (1100±50 °F) | | Fuel pressure | 137.9±13.8 kPa (20±2 lbf/in²) | | Exhaust back pressure | 1.24–2.99 kPa (5–12 inH₂O) | | Piston cooling oil pressure | 165.5±13.8 kPa (24±2 lbf/in²) | | Oil pressure (maximum) | 220.6 kPa (32 lbf/in²) | | Intake air pressure (absolute) | 178.9±1.0 kPa (53±0.3 inHg) | | Crankcase vacuum | 0.25±0.18 kPa (1.0±0.5 inH₂O) | | Intake air humidity | 18.0±1.7 g/kg (125±12 gr/lb) | Cool-down step (Table 3): the total cool-down time shall be 15–20 min. | Step | Speed, r/min | Load, kW | Intake air pressure (absolute) | Time, min | |---|---|---|---|---| | 1 | 1600 | 17.2 | 135.0±1.7 kPa | 5 | | 2 | 1000 | 7.5 | 118.2±1.7 kPa | 5 | | 3 | 1000 | 0 | 118.2±1.7 kPa | 5 | Warm-up step (Table 4): the total warm-up time shall be at least 30 min. | Step | Speed, r/min | Load, kW | Intake air pressure | Time, min | |---|---|---|---|---| | 1 | 1000 | 7.5 | 118.2±1.7 kPa | 5 | | 2 | 1000 | 17.2 | 118.2±1.7 kPa | 10 | | 3 | 1600 | — | 135.0±1.7 kPa | 15 | Air-fuel ratio: measured every 120 h, must be (23.5±1.0):1; it may be calculated by measuring the intake air flow with an orifice plate flowmeter, or derived from the exhaust gas analysis method in Table 5; the exhaust gas shall be sampled from the sampling tube on the exhaust pipe. Periodic measurements (8.12): record the test parameters once every hour (engine speed, fuel consumption rate, engine load, coolant outlet temperature, coolant inlet temperature, oil temperature, intake air temperature, exhaust temperature, oil cooler inlet temperature, oil pressure, piston cooling oil pressure, intake air pressure (absolute), exhaust back pressure, fuel pressure at the injection pump inlet, intake air humidity and crankcase vacuum); record the engine coolant flow every 12 h; record the crankcase blow-by every 12 h (10 min per measurement, two consecutive measurements averaged); calculate the test fuel consumption rate (mL/kW·h, based on a brake power of 31.3 kW) each time the test oil is changed every 120 h.

Calculation and results: Definition of deposits (9.3.1): Carbon deposits: black, hard and poorly soluble deposits, whose surface has no gloss except for parts that have rubbed against components. Piston ring groove carbon deposits are graded as heavy, medium and light: Heavy carbon: carbon deposit fills the entire space behind the piston ring and ring groove, and also includes parts that, although of smaller thickness, have been polished by excessive carbon behind the ring. Medium carbon: carbon deposit occupies more than 1/4 of the space behind the piston ring and ring groove. Light carbon: carbon deposit occupies less than 1/4 of the space behind the piston ring and ring groove. Piston ring land carbon deposits are graded as heavy and light: Heavy carbon: carbon deposit shows traces of rubbing and polishing. Light carbon: other carbon deposits. Lacquer: a very thin, hard, glossy and poorly soluble deposit, classified by colour into six grades — black, dark brown, brown, light brown, discoloured and clean — distinguished by comparison with a standard colour plate. Rating environment (9.3.2): rating shall be carried out in a standard rating box; to improve rating accuracy, a rating mask is used to divide the piston measurement surface into 20 equal parts, each part accounting for 5% of the total area. Rating (9.3.3): Rating of deposits: align zone No. 1 of the rating mask with the front of the piston, and observe separately the coverage area of each category of deposit in each zone of the piston, accurate to 1%. Coefficients for each deposit category and zone weighting factors: Carbon deposit coefficients: heavy carbon 1.00; medium carbon 0.50; light carbon 0.25. Lacquer deposit coefficients: black 0.100; dark brown 0.075; brown 0.050; light brown 0.025; discoloured 0.010; clean 0.000. Zone weighting factors: first ring groove 35; second ring groove 70; third ring groove 35; fourth ring groove 20; second ring land 3.5; third ring land 10; fourth ring land 3.5 (note: the arrangement of zone weighting factors in the [source unclear] table is misaligned, [to be verified] ([source unclear])). Calculation of the rating: Zone rating = percentage of deposit coverage area × deposit coefficient Zone weighted rating = sum of zone ratings × zone weighting factor Total weighted rating = sum of the zone weighted ratings The percentage of deposit coverage area is expressed as an integer. When calculating the zone weighted rating, only one decimal place is retained; the second decimal place is handled according to the "rules for rounding off numerical values". Reporting of test results (9.4): the test result report includes the bench reference oil test results and the piston rating of the test oil, test conditions, test oil consumption, wear condition, piston photographs, shutdown condition, etc.; the report format is given in Annex C (supplementary). Precision (10): the test precision is given in Annex E (reference). Annex E Test precision (reference): Reference oil REO-203: number of tests 52; arithmetic mean of first ring groove carbon filling rate 69; arithmetic mean of total weighted rating 180, standard deviation 102. Reference oil REO-191: number of tests (not provided in the available material); arithmetic mean of first ring groove carbon filling rate 91; arithmetic mean of total weighted rating 386, standard deviation (not provided in the available material). Note: the table in Annex E is [source unclear] and misaligned; some values [to be verified] ([source unclear]).

Quality control: The test precision is given in Annex E (reference). The Annex E data are given in clause 9. Note: the number of tests and the standard deviation of the total weighted rating for REO-191 in Annex E are not found in the original and are [source unclear], [to be verified] ([source unclear]).

Normative references: GB 261 Petroleum products — Determination of flash point (closed cup method) GB 265 Petroleum products — Determination of kinematic viscosity GB 380 Petroleum products — Determination of sulfur content (lamp method) GB 386 Determination of cetane number of diesel fuels (simultaneous flash method) GB 508 Petroleum products — Determination of ash GB 1884 Petroleum and liquid petroleum products — Determination of density (hydrometer method) GB 1885 Petroleum density metering conversion tables GB 1922 Solvent naphtha GB 3535 Petroleum — Determination of pour point GB 4945 Petroleum products and lubricants — Determination of neutralization value (colour indicator method) GB 5096 Petroleum products — Copper strip corrosion test GB 6533 Crude petroleum — Determination of water and sediment GB 6536 Petroleum products — Determination of distillation ZB E 30001 Petroleum products — Determination of carbon residue (Ramsbottom method) SY 2204 Light petroleum products — Determination of cloud point and crystallization point Note: in clause 2 of the original the title of GB 261 contains a misprinted character, so that it reads as "stone-alone petroleum products" instead of "petroleum products"; it should read "Petroleum products — Determination of flash point", [to be verified] ([source unclear]).

Evidence note: [to be verified] and [source unclear] mark specific points that still require checking against the original text of the standard and do not indicate that they have been verified. Do not use these values or steps directly as a basis for work.

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