JB/T 11880.7-2014Diesel engines - Selective catalytic reduction (SCR) systems - Part 7: NOx sensors (English PDF)

3.1 NOx sensor

The sensor that detects nitrogen oxide (NOx) content such as NO, NO2 in engine exhaust. According to the working principle, it can be divided into electrochemical NOx sensor, optical NOx sensor, optical fluorescent NOx sensor and NOx sensor of other principles.

3.2 Electrochemical NOx sensor

The sensor that detects the content of nitrogen oxides in engine exhaust by […]

4.6.1 Low temperature resistance

The sensor control unit (SCU) of the NOx sensor is subjected to a low temperature test at -40°C for 48h (24h low temperature storage, 24h low temperature operation). After the test is completed and cooled to room temperature, the functional state shall comply with level A as specified in Annex C.

4.6.2 High temperature resistance

The sensor control unit (SCU) of the NOx sensor is subjected to a high temperature test at 85°C for 72h (24h high temperature storage test, 48h high temperature operation test). After the test is completed and cooled to room temperature, the functional state shall comply with level A as specified in Annex C.

4.6.3 Resistance to temperature changes

After the NOx sensor has undergone the temperature change test, the functional state shall comply with level A specified in Annex C. The overall appearance of the sensor is free of cracks and other adverse conditions.

4.7 Resistance to temperature/humidity combined cycle change

After the NOx sensor is subjected to the temperature/humidity cycle test, the functional state shall be in accordance with level A specified in Annex C. The overall appearance of the sensor is free of rust and other bad conditions.

4.8 Anti-drop performance

The NOx sensor is subjected to the anti-drop test. After the test, the shell is allowed to be slightly damaged without affecting the performance of the product.

Its functional state shall comply with level A as specified in Annex C.

4.9 Vibration resistance

The NOx sensor is subjected to the vibration resistance test. After the test, there shall be no damage or loose parts. The functional state shall comply with level A as specified in Annex C.

4.10 Salt spray resistance

The NOx sensor is subjected to the salt spray resistance test. After the test, the functional state shall comply with level A specified in Annex C.

4.11 Protection performance

4.11.1 Anti-foreign properties

According to the provisions of GB/T 17619-1998, choose one of the methods for testing, such as strip line method, free field method.

5.5.2 Anti-static discharge interference test

Test according to the provisions of GB/T 19951-2005. The discharge level of contact discharge and air discharge is ±4kV. In the charging mode and non-charging mode, test the accessible surface of the sensor control unit (SCU). Non-charging mode also requires testing each pin of the connector.

5.5.3 Transient immunity test along the power line

In accordance with the provisions of Clause 2 in GB/T 21437.2-2008.

5.5.4 Electromagnetic disturbance test

In accordance with the provisions of GB/T 18655-2010.

5.6 High and low temperature resistance test

5.6.1 Low temperature resistance test

In accordance with the provisions of test Ab in GB/T 2423.1.

5.6.2 High temperature resistance test

In accordance with the provisions of test Bb in GB/T 2423.2.

5.6.3 Temperature change resistance test

According to the method specified in test Na in GB/T 2423.22, the NOx sensor part and the sensor control unit part are tested separately according to the test parameters specified in Figure 2. The high temperature of the sensor part, TB, is 120°C. and the part of the sensor control unit are separately subjected to the frequency sweep vibration test in the X, Y, and Z directions. The severity level of the frequency sweep vibration test of the sensor part shall be in accordance with the provisions of "Product installation locates on engine" in 3.12 of QC/T 413-2002. The severity level of the frequency sweep vibration test of the sensor control unit is in accordance with the provisions of "Product installation locates at other locations" in 3.12 of QC/T 413-2002.

5.10 Salt spray resistance test

According to the provisions of GB/T 2423.17, the NOx sensor is subjected to the salt spray resistance test for 144h.

5.11 Protection performance test

5.11.1 Anti-foreign test

According to the provisions of the IP6X test method in GB 4208, the NOx sensor is tested for foreign matter prevention.

5.11.2 Waterproof test

According to the provisions of the IPX7 test method in GB 4208, perform a short-time immersion test on the NOx sensor and the cable joint part. During the test, the NOx sensor probe is sealed to avoid the sensor chip being immersed in water. Carry out the waterproof test for the NOx sensor control unit (SCU) according to the provisions of the IPX9 test method in GB 4208. Connect the corresponding plug to the connector during the test.

5.12 Industrial solvent resistance test

Carry out the test according to the provisions of test XA in GB/T 2423.30.

Solvents are recommended to use brake fluid, antifreeze, engine oil, engine fuel (diesel or gasoline) and urea and other solvents. The test requirements are as follows:

- Dipping duration: 5 min ± 0.5 min;

- Test temperature: room temperature.

After the sensor is removed from the solvent, it is kept under normal atmospheric conditions for 2h.

5.13 Durability test

According to the durability test method specified in HJ 438-2008, conduct the durability test not less than 1000h on the engine bench for the NOx sensor.

Conduct the durability test not less than 800h at 85°C for the NOx sensor control

a) manufacturer's name or trademark;

b) product model;

c) production date or production batch number;

d) main technical parameters of the product, such as 12V/24V.

According to the specific situation, additional items can be listed according to user requirements.

7.1.2 Packaging marks

The basic content of packaging marks includes:

a) contents of product sign related to delivery: product name and trademark, product model, specifications, customer drawing number;

b) manufacturer name, detailed address, postal code and telephone number, fax;

c) production date or production batch number;

d) graphic mark for packaging, storage and transport: comply with the relevant regulations of GB 191-2008;

e) text of the transport operation: the overall dimensions of the packaging box (length × width × height), the number of products in each box, and the total mass of the products in each box. According to the specific situation, additional items can be listed according to user requirements.

7.2 Packaging

7.2.1 The packaging shall meet the requirements of GB/T 13384-2008. The probe and connector of the sensor shall have protective measures (such as shield, sheath) to prevent the inner cavity from being contaminated.

7.2.2 The packaging box shall be accompanied by product inspection certificate, product manual and relevant exit-factory documents.

7.3 Transport

Ensure that the product is not damaged and damp during transportation.

7.4 Storage

The products shall be stored in a dry, ventilated, non-corrosive warehouse. At the end of the storage period (24 months from the manufacturer's storage), the product shall still meet the relevant regulations of this Part. […]