QC/T 29061-2013Technical specifications for wax thermostats of automotive engines (English PDF)

3.1 Start to open temperature

During the temperature rise of the medium, the temperature of the medium when the open stroke of the main valve of the thermostat reaches A (see Table 1 and Figure 1).

Main valve form Main valve open stroke A Metal main valve 0.10 mm Rubber main valve 0.35 mm Unless otherwise specified, the hysteresis is not more than 2.5 °C. The determination point is 50% of the minimum value of the full open stroke.

4.8 Opening sensitivity

The opening sensitivity is not more than 20 s unless otherwise specified.

4.9 Fully opened sensitivity

The fully opened sensitivity is no more than 90 s unless otherwise specified.

4.10 Cleanliness

The mass of the impurities is not more than 60 mg unless otherwise specified.

4.11 Closing jiggle valve pressure

The closing jiggle valve pressure is as specified in the drawings and technical documents.

4.12 Air flow of jiggle valve

The air flow of jiggle valve is as specified in the drawings and technical documents.

4.13 Difference of pressure to open valve

The difference of pressure to open valve is as specified in the drawings and technical documents.

4.14 Low temperature resistance

The thermostat shall be able to withstand a low temperature test of (-40 ± 2) °C for 24 h, the start to open temperature change before and after the test is not more than 1 °C.

4.15 High temperature resistance

The thermostat shall be able to withstand the high temperature test of (135 ± 2) °C for 1 h. The start to open temperature change before and after the test is not more than 2.5 °C, the full open stroke change rate is not more than 12%.

4.16 Durability

After 3.0 x 10^4 full opening and closing, the start to open temperature change before and after the test is not more than 3 °C, the full open stroke change rate is not more than 15%, the leakage after the test is increased by 12% within the initial specification value.

4.17 Vibration resistance

The thermostat is oscillated by adding 30 g in each of the specified X-X and Y- Y directions, at the vibration frequency of 300 Hz, to perform the vibration resistance test, and the running time is 24 hours. Before and after the test, the start to open temperature change is not more than 3 °C, the full open stroke change rate is not more than 15%, the leakage change is not more than 12% of the maximum value specified in the drawing.

4.18 Damage strength

The thermostat bracket and the valve seat disintegrate or the damage strength is not less than 900 N.

4.19 Salt spray resistance

The thermostat is tested in accordance with the neutral salt spray test (NSS test) as specified in GB/T 10125. The judgment criteria of the test results is determined by both parties through negotiation.

5.1 Test equipment

- Constant temperature test chamber (the temperature inside the chamber shall be above 135 °C);

- Salt spray test chamber;

- Low temperature test chamber (the temperature inside the chamber shall be below -40 °C);

- Cleanliness test bench;

- Vibration test bench;

- Jiggle valve characteristic test bench;

- Strength test bench;

- Difference of pressure to open valve test bench.

5.2 Test equipment

- Mercury thermometer (accuracy 0.1 °C);

- Flow meter or measuring cup (accuracy 1%);

a) Product of trial production and first batch production.

b) Products that have undergone major changes in structure, materials, and processes after formal production.

c) The production is discontinued for more than one year and then restored.

d) The product proposed by the customer for type inspection.

e) During normal production, a type inspection is carried out once a year, where durability test is carried out once every two years.