An overview of the working principle of automotive electronic water pumps

- Dec 17, 2020-

An overview of the working principle of automotive electronic water pumps


The main function of the working principle of the electronic water pump is to forcibly cool the oil at the turbine shaft after flameout. Turbine lubrication and cooling system. The outside of the turbine shaft is covered by oil. Because the oil inlet is much larger than the oil outlet, an oil film will be established between the turbine shaft and the housing under the action of the oil pressure to lubricate the turbine. Shaft, and take away a part of the heat of the turbine (the heat taken away by the oil is finally dissipated through the oil pan and the oil cooler); the outside of the turbine housing that is in contact with the oil is wrapped by cooling water, also due to the intake The water outlet is much larger than the water outlet, and the cooling water between the shells here will also have a certain pressure, but the pressure is mainly to ensure that the cooling water maintains good contact with the shell and ensures sufficient cooling effect. Why cool the vortex: Because the rotation of the turbine blades is produced by the impact of exhaust gas after the engine is working, in addition to the heat of the exhaust gas, part of the kinetic energy of the exhaust gas will also be converted into heat during the process of impacting the turbine blades, so the turbine will become very hot (In extreme cases, it can exceed 700°C. At this time, the entire turbine body is red, just like burning red briquettes.

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Under normal circumstances, if you have just finished running at a high speed, immediately park the car in a dark place, you can see that the turbine is reddish. ), if the turbine shaft cannot be cooled in time, the oil will become extremely thin due to high temperature, and a sufficient oil film cannot be established to ensure the lubrication of the turbine shaft. Moreover, due to the high temperature, the oil is easily oxidized and deteriorated (severely deteriorated Engine oil is like chocolate melted in the hand), which will eventually cause the vicious consequences of the engine's entire lubrication system failure. Therefore, forced cooling of the turbine shaft is necessary. When the vehicle is in motion, the water pump of the engine will provide sufficient cooling water circulation. Once the vehicle is turned off, because the turbine blades will continue to rotate due to inertia, a small amount of oil must be stored in the bearing area of the turbine shaft to avoid the wear of the journal, so the electronic water pump will work for a while to provide sufficient cooling water It is used to cool the oil at the turbine shaft to avoid deterioration of the oil here due to overheating of the turbine and damage to the engine. ) The engines are all arranged horizontally, and their turbines are located between the engine and the rear bulkhead of the engine compartment. Compared with other longitudinally arranged models, the flowing air has a poorer heat dissipation effect on them. Therefore, the electronic water pump is used as a heat sink for the engine. The extra protection is also very beneficial.


So theoretically speaking, the vehicle does not need to idle a little to help the turbine cool down before stalling, but the running time of the electronic water pump is not fixed, and its control strategy is very complicated: the ECU will be based on the water temperature, the ambient temperature, the load of the engine before the stall, etc. A variety of factors calculate a suitable time to control its reasonable operation. The result not only reduces the impact of high temperature on the oil, but also is very beneficial to prolong the life of the battery. The above is the analysis of the principle of the water pump.