GB/T 37322-2026 Gasoline Detergency Evaluation—Simulated Test Method for Intake Valve Deposits of Gasoline Engines

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Card type: Test method

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

• Standard number: GB/T 37322—2026
• Chinese name: Gasoline Detergency Evaluation—Simulated Test Method for Intake Valve Deposits of Gasoline Engines
• English name: Evaluation of gasoline cleanliness—Simulation test method for intake valve deposit (IVD) on gasoline engine
• Replacement relationship: replaces GB/T 37322—2019; this document was first issued in 2019, and this is the first revision
• Publication/implementation: published on 2026-03-31, implemented on 2026-10-01
• Secretariat: National Technical Committee for Standardization of Petroleum Products and Lubricants (SAC/TC280)
• Main technical changes compared with the 2019 edition (as listed in the foreword a)~r)): changed the test ambient temperature and added a relative humidity requirement (see Chapter 5); deleted ferric naphthenate diluent and calibration reference fuel; added washing liquid specifications (see 7.1.1); changed the rubber-forming agent requirements (see 7.2.3); changed the calibration reference detergent requirements (see 7.2.4); changed the test base oil requirements (see 7.2.5); changed the sample preparation requirements (see 8.3); added the fuel injection process temperature requirement (see 9.1.3); changed the deposit collector treatment steps (see 9.2); changed the photography requirements (see 9.3); changed the precision (see Chapter 11); changed the test report content (see Chapter 12); changed the technical requirements for the plate heater, clamping device, test chamber, and axial fan (see A.2.3, A.2.4, A.2.6, A.2.7); added an exhaust gas absorption system (see A.3.3); changed the automatic control system requirements (see A.3.4); changed the component calibration requirements (see A.4); added Annex B (normative) 'Technical Requirements for Test Base Oil'; added Annex C (normative) 'Calibration of Rubber-Forming Agent Dosage'.

2. Scope of application and non-applicability

• This document describes a simulated test method using a port fuel injection gasoline engine for intake valve deposits, to evaluate the tendency of gasoline engines to form intake valve deposits.
• It is applicable to the detergency evaluation of automotive gasoline and automotive gasoline detergents.
• Not applicable: not provided in the available source.

3. Method principle

Under specified test conditions, a quantitative sample is mixed with air through a nozzle and sprayed onto a heated deposit collector to simulate the formation of gasoline engine intake valve deposits. After soaking separately in test base oil and petroleum ether, the mass of the insoluble deposits produced is weighed and photographed. (See Chapter 4)

4. Reagents and materials (purity / preparation)

4.1 Reagents

• Washing liquid: prepared from n-heptane and xylene at a volume ratio of 2:1 (7.1.1).
• Petroleum ether: distillation range 60 ℃~90 ℃, analytical reagent (7.1.2).
• Anhydrous ethanol: purity 99.5% or above (7.1.3).

4.2 Materials

• Scouring pad: grit 240 to 280 (7.2.1).
• Water sandpaper: 62 μm (7.2.2).
• Rubber-forming agent: the main component is dicyclopentadiene, with a mass fraction not less than 90% (7.2.3).
• Calibration reference detergent: meets the requirements of GB 19592 (7.2.4).
• Test base oil: meets the technical index requirements in Table B.1 of Annex B, and meets the other technical index requirements for Stage VI 95 gasoline in GB 17930, contains no gasoline detergent, and after adding a calibrated amount of rubber-forming agent, the measured simulated intake valve deposit mass is 7 mg~9 mg (7.2.5).
• Cleaning agent: commercially available detergent (7.2.6).
• Paper stick: made by rolling filter paper, diameter 1.5 mm (7.2.7).

5. Instruments and equipment

• Gasoline engine intake valve deposit simulation test machine: technical requirements meet the requirements of Annex A (6.1).
• Analytical balance: scale interval 0.1 mg (6.2).
• Desiccator: containing desiccant (6.3).
• Oven: temperature controllable at 20 ℃~200 ℃, precision ±2 ℃ (6.4).
• Microsyringe: 1000 μL (6.5).
• Graduated cylinder: 500 mL (6.6).
• Tweezers: wooden (6.7).
• Gloves: antistatic material (6.8).
• Sample cup: 500 mL, brown glass cup (6.9).
• Digital camera: not less than 1600 megapixels (6.10).

6. Recommended operating conditions

• Ambient temperature 20 ℃~25 ℃, relative humidity not greater than 70% (Chapter 5).
• Test machine parameter settings: test time 85 min; test temperature 175 ℃; temperature control precision ±1 ℃ (8.2.1).
• Air pressure (80±1) kPa, air flow rate (700±20) L/h (8.2.2).
• Gear pump flow rate adjustment: make 300 mL test base oil finish spraying within 73 min~75 min (8.2.7).
• Fuel injection stage: start fuel injection after the test temperature reaches 175 ℃, after 3 min the temperature returns to 175 ℃, and the temperature fluctuation during the fuel injection stage is not greater than ±1 ℃ (9.1.3).

7. Sampling and sample preparation

7.1 Sampling

• Take a representative gasoline sample in accordance with GB/T 4756. Samples should avoid exposure to sunlight or ultraviolet light and be stored in light-protected containers, such as dark brown glass bottles, metal cans, etc. (8.3.1).
• For samples stored at low temperature, before testing, they should be restored to room temperature 20 ℃~25 ℃ (8.3.2).

7.2 Sample preparation

• Automotive gasoline sample: use a graduated cylinder to take 300 mL of the gasoline sample to be tested and pour it into the sample cup, use a 1000 μL microsyringe to draw a calibrated amount (according to C.3 of Annex C) of rubber-forming agent, add it to the gasoline sample to be tested and mix evenly, then tighten the cup lid (8.3.3 a)).
• Automotive gasoline detergent sample: sequentially add the nominal dose of the automotive gasoline detergent to be tested, 300 mL test base oil, and a calibrated amount (see C.3) of rubber-forming agent into the sample cup, mix evenly, and tighten the cup lid. If the nominal dose of the detergent product is given as a range, prepare the sample according to the minimum value of the range (8.3.3 b)).
• The same batch of test base oil should be used for calibration of the rubber-forming agent dosage and for diluted detergent samples (8.3.4).

7.3 Preparation of the deposit collector

• Use a scouring pad dipped in water and cleaning agent to grind in a straight line along the length direction of the deposit collector plate surface until the surface is bright and free of contamination; if there is a large amount of residual deposit, first grind with water sandpaper dipped in water, then use a new scouring pad to grind in a single direction in running tap water and clean thoroughly (8.1.1).
• If there is oil contamination at the edges and corners, handle it with reference to 8.1.1 (8.1.2).
• Place in anhydrous ethanol solution and soak for about 5 min, transfer with tweezers to an oven, and bake at 100 ℃ for not less than 2 h (8.1.3).
• Remove and cool to room temperature, insert a paper stick into the thermocouple hole to ensure there is no residual material in the temperature measuring hole, and place in a desiccator for not less than 4 h (8.1.4).
• Remove from the desiccator and weigh, put back into the desiccator, weigh again after an interval of 10 s, and when the difference between consecutive 2 readings is not greater than 0.1 mg, record the pre-test mass m0 (8.1.5).
• If the difference is greater than 0.1 mg, put it back into the desiccator for 30 min and weigh again, until the difference between consecutive 2 readings is not greater than 0.1 mg (8.1.6).
• Note: spare deposit collectors must not be touched directly with bare hands; gloves must be worn when handling them (8.1.6 Note).

7.4 Preparation of test equipment

• Connect the gas source, adjust the air pressure to (80±1) kPa, and the air flow rate to (700±20) L/h (8.2.2).
• Pour 30 mL of washing liquid into the sample cup, cover the cup lid, shake vigorously to clean the inner wall of the sample cup, and pour out the waste liquid (8.2.3).
• Pour 30 mL of washing liquid into the sample cup, cover the cup lid, place the solvent recovery box in front of the nozzle, and close the glass sliding door (8.2.4).
• Turn on the equipment power switch, use the cleaning mode, and make the solution in the sample cup pass quickly through the fuel inlet pipe and nozzle and spray toward the solvent recovery box until spraying is complete (8.2.5).
• Continue blowing air for about 3 min to dry the pipeline, end the cleaning mode, switch to test mode, and take out the solvent recovery box (8.2.6).
• Note: avoid touching the fuel injector when placing and removing the solvent recovery box (8.2.6 Note).

8. Analysis procedure

8.1 Deposit formation

• Place the sample cup containing the sample at the port of the test machine fuel inlet pipe, and insert the fuel inlet pipe to the bottom of the cup (9.1.1).
• Install and clamp the weighed deposit collector, and insert the temperature measuring thermocouple (9.1.2).
• Start the test machine and conduct the test according to the set test conditions. Start fuel injection after the test temperature reaches 175 ℃, monitor the temperature change curve in real time, after 3 min the temperature returns to 175 ℃, and the temperature fluctuation during the fuel injection stage is not greater than ±1 ℃ (9.1.3).
• After fuel injection ends, remove the temperature measuring thermocouple inserted in the deposit collector, and release the deposit collector (9.1.4).

8.2 Treatment of the collector

• Use tweezers to remove the deposit collector, wait until it cools to room temperature, fully immerse it in a container containing test base oil, with the angle between the plate length direction and the container bottom greater than 45°, let it soak statically for 6 min, then remove it (9.2.1).
• Immerse the sediment collector completely in a container filled with petroleum ether, with the angle between the length direction of the plate and the horizontal bottom of the container greater than 45°, let it soak statically for 1 min, then remove it, and use a paper stick to absorb the reagent in the thermocouple hole (9.2.2).
• Place in an oven at 100 ℃ and dry for 15 min, then remove and place in a desiccator, and cool for not less than 1 h (9.2.3).
• Weigh, and the difference between the mass readings obtained from 2 consecutive weighings shall not be greater than 0.1 mg; record the mass after the test m1; if the difference is greater than 0.1 mg, place it back in the desiccator for 30 min and then weigh again, until the difference between readings from 2 consecutive weighings is not greater than 0.1 mg (9.2.4).

8.3 Photograph

• Use a digital camera to photograph the sediment collector after the test (9.3).
• Note: The sediment generated on the sediment collector is generally dumbbell-shaped, with a length of about 0 mm–80 mm and a width of about 0 mm–50 mm (9.3 Note).

9. Qualitative and Quantitative Determination and Calculation Formula

The mass of simulated intake valve deposit of the test sample is calculated according to formula (1), and the result is accurate to 0.1 mg:

m = m1 − m0 …………………………(1)

Where:

• m —— the mass of simulated intake valve deposit generated, in milligrams (mg);
• m1 —— the mass of the sediment collector after the test, in milligrams (mg);
• m0 —— the mass of the sediment collector before the test, in milligrams (mg).

10. Precision

10.1 Overview

The precision of this document was obtained through statistical analysis according to GB/T 6683.1 based on the test results of 6 laboratories on 2 automotive gasoline samples and 5 automotive gasoline detergent additive samples. The reliability of the test results is judged by 11.2 and 11.3 (95% confidence level).

10.2 Repeatability (r)

In the same laboratory, by the same operator, using the same apparatus, the difference between 2 consecutive test results obtained on the same test sample shall not exceed the repeatability in Table 1.

10.3 Reproducibility (R)

In different laboratories, by different operators, using different apparatus, the difference between 2 single, independent test results obtained on the same test sample shall not exceed the reproducibility in Table 1.

Table 1 Repeatability and Reproducibility (in milligrams)

Note: m₁ is the arithmetic mean of 2 test results under repeatability conditions, and m₂ is the arithmetic mean of 2 test results under reproducibility conditions, in milligrams (mg). (Note: In the table, “0.327 m₁ 0.2” and “0.605 m₂ 0.2” are extracted as-is from source-text extraction; the formula layout is suspected to have lost superscripts/subscripts or multiplication signs, and requires confirmation against the source standard (source-text extraction).)

11. Report

The report shall at least include the following contents (Chapter 12):

• a) Sample information, sample type;
• b) Ambient temperature, relative humidity;
• c) The deposit mass of the test sample;
• d) When the sample is an automotive gasoline detergent additive, also report the deposit mass of the test base oil determined according to C.3;
• e) Image of the sediment collector after the test.

12. Normative References

• GB/T 503 Determination of knock characteristics of gasoline—Motor method
• GB/T 1884 Standard test method for density of crude petroleum and liquid petroleum products (Hydrometer method)
• GB/T 1885 Petroleum measurement tables
• GB/T 4756 Standard practice for manual sampling of petroleum liquids
• GB/T 5487 Determination of knock characteristics of gasoline—Research method
• GB/T 6536 Standard test method for distillation of petroleum products at atmospheric pressure
• GB/T 8017 Standard test method for vapor pressure of petroleum products—Reid method
• GB/T 8019 Standard test method for gum content in fuels—Jet evaporation method
• GB/T 11132 Standard test method for hydrocarbon types in liquid petroleum products—Fluorescent indicator adsorption method
• GB 17930 Automotive gasoline
• GB/T 19230.6 Test method for evaluating the effectiveness of gasoline detergent additives—Part 6: Engine bench test method for the effect of gasoline detergent additives on the tendency to form deposits on intake valves and combustion chambers of gasoline engines (M111 method)
• GB 19592 Automotive gasoline detergent additive
• GB/T 28768 Determination of hydrocarbon types and oxygenates in automotive gasoline—Multidimensional gas chromatography
• GB/T 30519 Determination of hydrocarbon group composition and benzene content in light petroleum distillates and products—Multidimensional gas chromatography
• NB/SH/T 0663 Determination of alcohols and ethers in gasoline—Gas chromatography
• SH/T 0604 Standard test method for density of crude petroleum and petroleum products (U-shaped oscillating tube method)
• SH/T 0720 Standard test method for determination of oxygenates in gasoline (Gas chromatography and oxygen-selective flame ionization detector method)
• SH/T 0794 Determination of vapor pressure of petroleum products—Mini method
• Reference: [1] GB/T 6683.1 Petroleum and related products—Determination of precision of measurement methods and results—Part 1: Determination of precision data of test methods

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 for Questions and Answers