JB/T 11880.2-2014Diesel Engines - Selective Catalytic Reduction (SCR) Systems - Part 2: Urea Solution Tanks (English PDF)

5.1 General technical requirements

5.1.1 Working temperature

The operating temperature range of the urea solution tank is -40 °C ~ 85 °C.

5.1.2 Materials

Selection of materials for the urea solution tank and its accessories shall meet the relevant requirements of the storage quality requirements of urea solution.

Please refer to Table A.1 and Table A.2 for material selection. All materials that cannot be determined whether they are compatible with the urea solution need to be tested, to evaluate the material's possible impact on the quality of the urea solution product.

5.1.3 Structure

5.1.3.1 If the urea solution tank is formed by processing the plastic materials, the tank can be divided into natural color black color. If there are special requirements, it shall be negotiated and determined by the supplier and the buyer.

5.1.3.2 The design of the filling port of the urea solution shall meet the requirements of Appendix B.

5.1.3.3 In order to meet the requirements of the urea solution tank level and temperature sensor to test the urea consumption, the parameters of the urea level sensor shall have a corresponding relationship with the actual volume.

Code of urea solution tank level and temperature sensor Rated volume Code of urea solution tank Carry out the test according to 6.6, the requirements are as follows:

a) Leakage and cracking are not allowed, but permanent deformation is possible.

b) At room temperature, the dimensional change rate of resistance to negative pressure is not more than 1%; at 50 °C, the dimensional change rate of resistance to negative pressure is not more than 3%.

5.2 Performance requirements

5.2.4 Low-temperature shock resistance of plastic urea solution tanks

After the test specified in 6.7, the urea solution tank is not allowed to leak.

5.2.5 Heat resistance of plastic urea solution tank

Carry out the test according to 6.8, and the requirements are as follows:

a) When filling liquid, the urea solution tank is not allowed to leak;

b) When there is no liquid, there is no abnormal phenomenon such as deformation or discoloration by visual inspection.

5.2.6 Weather resistance of plastic urea solution tank

After the test specified in 6.9, the comparison grade of the gray scale for discoloration of the plastic urea solution tank is grade 4 ~ grade 5.

5.2.7 Environmental stress cracking resistance of plastic urea solution

tanks The environmental stress cracking time of the urea solution tank material is not less than 200 h.

5.2.8 Chemical resistance

The urea solution tank has no abnormal phenomena such as dissolution, swelling, discoloration, or cracks.

5.2.9 Internal cleanliness

The total amount of impurities in the urea solution tank assembly is less than 100 mg.

5.2.10 Ventilation

Minimum ventilation of the air vent is not less than 2 L/min.

6.6 Pressure resistance test

The urea solution tank is fixed on the test device in the simulated loading form.

Keep the ambient temperature of 50 °C ± 2 °C. Fill the urea solution tank with water of rated volume at a temperature of 50 °C ± 2°C. Close the lid. Seal all inlets and outlets. Apply a pressure of 30 kPa to the tank. Hold the pressure for 5 hours.

6.7 Low-temperature shock resistance test of plastic urea

solution tank It is performed according to the requirements of GB 18296.

6.8 Heat resistance test of plastic urea solution tank

According to the provisions of GB 18296, the urea solution tank is fixed on the test device in the form of simulated loading. Add 2/3 of the rated volume of water to the tank at room temperature. Place it at an ambient temperature of 85 °C ± 2 °C (such as placing it in 85 °C ± 2 °C water vapor medium) for 1 h.

If not filled with liquid, place it at 85 °C ± 2 °C ambient temperature for 200 h. Observe the appearance change after taking it out.

7.2 Exit-factory inspection

Before the product leaves the factory, it needs to be inspected by the company's quality inspection department in accordance with the provisions of this part.

After passing the inspection, the product can be delivered only after the product inspection certificate is issued. The inspection items, requirements and test methods of the exit-factory inspection shall be implemented in accordance with Table 2.

7.3 Sampling inspection

The sampling plan and the acceptance quality level AQL of the sampling inspection of the urea solution tank shall be implemented by the quality inspection department of the manufacturer in accordance with the relevant provisions of GB/T 2828.1. The inspection items, requirements and test methods of the sampling inspection shall be implemented in accordance with the provisions of Table 2.

7.4 Type inspection

7.4.1 Type inspection shall be carried out if one of the following situations occurs:

a) Trial type approval of new products or old products after trans-plant production;

b) There are major changes in structure, materials, and processes that may affect product performance;

c) Production restoration after one year of suspension;

d) The results of the exit-factory inspection are quite different from the results of the last type inspection;

e) During normal production, once a year;

f) The national quality supervision agency puts forward the requirements for type inspection.

7.4.2 The inspection items, technical requirements and test methods of type inspection shall be implemented in accordance with Table 2.

B.1 Scope

Appendix B specifies the most basic functional requirements and geometric dimensions of the filling port of the urea solution tank as well as the compatibility conditions with the external filling system.

B.2 Terms and definitions

B.2.1 Filling port of urea solution tank

Refers to the necessary device for filling the urea solution on the urea solution tank assembly, usually including a filler neck, an inlet adapter, a filler cap.

B.2.2 Filler neck

Refers to the connecting part of the urea solution tank where the solution is filled, the opening of which is the inlet adapter.

B.2.3 Inlet adapter

Refers to the part where the filler neck is connected to the external filling system.

It has a specified geometric size interface and integrates a magnetic ring. This magnetic ring can prevent the urea solution from being added to the fuel tank by mistake.

B.2.4 Filler cap

Refers to the parts installed on the filler neck to prevent the urea solution from overflowing and prevent contamination. It can be temporarily opened or removed during filling.

B.2.5 Open filling system

Refers to an ordinary filling system that does not require air-tightness between the filling nozzle and the filler neck, such as using a small volume container to inject urea solution into the open filling system.

B.2.6 Sealed filling system

Refers to a special filling system that requires air tightness between the filling nozzle and the filler neck. system to establish the liquid pressure required for normal operation.

C.2.2 Technical requirements

C.2.2.1 Appearance

The shape, size and tolerance of the sensor shall meet the requirements of the drawing.

The plating and coating on the surface of the sensor shall be free of defects such as peeling, spots, blistering, cracks. The fasteners shall not be loose or damaged. The sign (or lettering) shall be clear and fastened firmly.

C.2.2.2 Tightness (liquid heating only)

After the test specified in C.3.2, no air bubbles are generated at each connection of the sensor.

C.2.2.3 Insulation resistance

After the test specified in C.3.3, the insulation resistance between any lead wire of the sensor and the housing shall be greater than 20 Mohm.

C.2.2.4 Pressure resistance

Carry out the test according to the provisions of C.3.4; the burst pressure of the pipeline where the sensor is subjected to positive pressure shall not be less than 3 MPa, so as to ensure that the sensor can work normally under a pressure of not more than 1 MPa.

C.2.2.5 Output signal

Measure the output signal of the sensor according to the provisions of C.3.5; the value shall meet the requirements of the drawing; the deviation of the resistance value is within ± 1%.

C.2.2.6 Temperature resistance

Perform the test according to the method specified in C.3.5; the performance of the sensor meets the requirements of C.2.2.3 and C.2.2.5.

C.2.2.7 Internal cleanliness

The internal impurity content of the urea inlet and outlet pipes of the sensor is less than 100 mg […]

C.3 Test method

C.3.1 Appearance inspection