GB/T 37322-2026Evaluation of gasoline cleanliness - Simulation test method for intake valve deposits in gasoline engines (English PDF)

6.2 Analytical balance. with a readability of

0.1 mg.

6.3 Desiccator. Containing desiccant.

6.4 Drying oven. The temperature is controllable between 20°C and 200°C, with an accuracy of ±2°C.

6.5 Microsyringe. 1 000 µL.

6.6 Graduated cylinder. 500 mL.

6.7 Tweezers. Wooden.

6.8 Gloves. Antistatic material.

6.9 Sample cup. 500 mL, amber glass.

6.10 Digital camera. Resolution of at least 16 megapixels.

7.1.1 Washing solution. Prepared by mixing n-heptane and xylene in a

2.1 volume ratio.

7.1.2 Petroleum ether. Boiling range. 60°C to 90°C, analytical grade.

7.1.3 Anhydrous ethanol. Purity. >99.5%.

7.2 Materials

7.2.1 Scouring pad. Grit size. 240# to 280#.

7.2.2 Wet-or-dry abrasive paper. 62 µm.

7.2.3 Deposit accelerant. The main component is dicyclopentadiene, with a mass fraction of not less than 90%.

7.2.4 Calibration reference detergent. It complies with the requirements of GB 19592.

7.2.5 Test base oil. It complies with the requirements for test indicators in Table B.1 of Appendix B and the requirements for other test indicators of Grade 95 gasoline (Stage VI) in GB 17930; it contains no gasoline detergent, and yields a simulated intake valve deposit mass of 7 mg to 9 mg after the addition of a calibrated amount of deposit accelerant.

7.2.6 Cleaning agent. Commercially available detergent.

8.1 Preparation of the Deposit Collector

8.1.1 Using a scouring pad moistened with water and a cleaning agent, scrub the surface of the deposit collector plate in a straight line along its length until the surface of the deposit collector is shiny and free of stains. For deposit collectors with significant residual deposits, first polish the surface with wet-or-dry abrasive paper moistened with water until it is shiny and free of stains. Then, using a new scouring pad, scrub the surface of the deposit collector plate in a straight, unidirectional motion along its length under running tap water and clean it thoroughly, ensuring a uniform surface finish on the working face of the deposit collector.

8.1.2 If there are oil stains on the corners of the deposit collector, treat them according to the procedures in 8.1.1.

8.1.3 Immerse the deposit collector in an anhydrous ethanol solution for approximately 5 min; using tweezers, transfer the deposit collector to a drying oven and bake it at 100°C for no less than 2 h.

8.1.4 After removing the deposit collector from the drying oven and allowing it to cool to room temperature, insert a prepared paper swab into the thermocouple hole of the deposit collector to ensure that no residual material remains inside; then, place the deposit collector in a desiccator for at least 4 h. NOTE. Place the desiccator and the analytical balance in the same room to ensure that they share the same operating environment.

8.1.5 Remove the deposit collector from the desiccator and weigh it; return it to the desiccator, wait 10 s, and weigh it again. If the difference between two consecutive readings is no greater than

0.1 mg, record the mass of the deposit collector before testing as m0.

8.1.6 If the difference exceeds

0.1 mg, return the deposit collector to the desiccator and reweigh it after 30 min; repeat this process until the difference between two consecutive readings is no greater than

0.1 mg. NOTE. Do not touch the spare deposit collector with bare hands; wear gloves when handling it.

8.2 Preparation of Test Equipment

8.2.1 Parameter settings for the gasoline engine intake valve deposit simulation test apparatus.

--- Test duration. 85 min;

--- Test temperature. 175°C;

--- Temperature control accuracy. ±1°C.

8.2.2 Connect the air supply; adjust the air pressure to (80±1) kPa and the air flow rate to (700±20) L/h.

8.2.3 Pour 30 mL of washing solution into the sample cup, close the lid, shake vigorously to clean the inner walls of the sample cup, and discard the waste liquid.

8.2.4 Pour 30 mL of washing solution into the sample cup, close the lid, place the solvent recovery container in front of the nozzle, and close the sliding glass door.

8.2.5 Turn on the equipment power switch and activate the cleaning mode to rapidly spray the solution from the sample cup through the oil inlet pipe and nozzle into the solvent recovery container until spraying is complete.

8.2.6 Continue blowing air for approximately 3 min to dry the lines; terminate the cleaning mode, switch to the test mode, and remove the solvent recovery container. NOTE. Avoid touching the injection nozzle when inserting or removing the solvent recovery container.

8.2.7 Adjust the gear pump flow rate so that 300 mL of test base oil is sprayed within 73 min to 75 min.

8.3 Sample Preparation

8.3.1 Obtain a representative gasoline sample in accordance with GB/T 4756.Samples should be protected from exposure to sunlight or ultraviolet light and stored in light-resistant containers, such as dark brown glass bottles or metal cans.