QC/T 288.2-2001Test methods for automotive engine coolant pumps (English PDF)

4.1 Exit-factory inspection

Exit-factory inspection items are as follows. Sealing test.

4.2 Type inspection

Type test items include.

a) Cavitation test;

b) Reliability test;

c) Sealing test; d) Performance test.

5.1 Test media

5.2 Test medium temperature

a) Performance test and cavitation test. Water temperature 80°C ± 2°C;

b) Reliability test. The maximum temperature of cooling liquid when engine works continuously (90°C ± 2°C when the maximum temperature is unknown);

c) Sealing test. Air temperature is ambient temperature.

a) Performance test and cavitation test. Clear water;

b) Reliability test. Cooling liquid that is used by the installed engine;

c) Sealing test. Air.

5.3 Test bench

a) Performance test may be carried out on open or closed test bench, as shown in Figure 1 and Figure 2;

6.1 Performance test

6.1.1 TEST the water pump flow, shaft power of water pump at different revolving speeds and shaft power; DRAW the graph of relation among its lift, shaft power, pump efficiency and flow.

6.1.2 For rated revolving speed of which the range of speed is about 40%~120%, select 4 or more different revolving speeds with the same intervals for test; or select revolving speeds according to typical working conditions of engine.

6.1.3 Select at least 8 flow points at the same internals from maximum flow value to minimum stabilization measured value, under each kind of test revolving speed for test.

6.1.4 During data measurement, all instruments shall be read at the same time.

6.2 Cavitation test

Measure the relation among flow, lift and NPSH, within water pump working range; draw corresponding curve chart.

6.2.1 Test the calibrated flow point or required flow points at rated revolving speed for test. Measure revolving speed, flow, lift, inlet pressure and water temperature.

6.2.2 During cavitation test, the changes of lift are divided into two stages.

a) The phase that lift H does not change with net positive suction head (NPSH);

b) The phase that lift H dramatically changes with net positive suction head (NPSH), i.e. fracture stage.

6.2.3 During test for each flow, select at least 10 different net positive suction head (NPSH) to draw cavitation performance curve. Net positive suction head (NPSH) interval shall be liquid; its calculation formula is as follows. Where, Pu - Output power of water pump, kW; Q - Flow, L/min.

7.5.2 Calculation formula of water pump efficiency eta

7.6 Determination of NPSH

7.6.2 Critical net positive suction head (NPSH) c refers to the NPSH when lift H decreases by 2% on the performance curve of lift and NPSH.

7.6.1 Calculation formula of NPSH

Where, (NPSH) - Net positive suction head, m; H1 - Inlet gross head, m; P0 - Atmospheric pressure during test, kPa;

Pv - Vapor pressure of water at test temperature, kPa, see Annex A1. When inlet pressure is measured through pressure sensor.

Where, Z1 - Vertical distance from pressure sensor to water pump center, m. When pressure sensor is higher than pump center, Z1 is a positive value; on the contrary, Z1 is a negative value;

P1 - Inlet pressure reading, kPa. P1 is a positive value when P1 >P0; P1 is a negative value when P1< P0.