BMW N52, N54, N20 and other engines all use electronic water pumps , instead of mechanical water pumps, the water pump is driven by electricity, and the speed of the water pump is no longer directly affected by the engine speed.

Taking the BMW N52 engine as an example, the electronic water pump is mainly composed of a centrifugal impeller, a three-phase brushless DC motor and an electronic module. The engine control unit determines the required cooling power according to the engine load, temperature sensor data and temperature operating mode, and then sends the relevant information to the electronic module in the electronic water pump through the serial data interface (BSD) to adjust the three-phase brushless DC motor的rpm。 N52 engine has 4 temperature operating modes: in economy mode, the engine coolant temperature is set to 112°C; in normal mode, the engine coolant temperature is set to 105°C; in high power mode, the engine coolant temperature is set to 95°C; high In power + characteristic curve thermostat (KFT) mode, the engine coolant temperature is set to 80°C. Increasing the engine coolant temperature can help reduce fuel consumption under low load conditions. Lowering the engine coolant temperature can increase the volumetric efficiency of the engine, thereby increasing the engine torque.

BMW engine electronic water pump wire connector terminal 1 is the 15th power supply terminal, which supplies power to the electronic module; terminal 2 is the BSD communication terminal; terminal 3 is the No. 30 power supply terminal, which supplies power to the three-phase brushless DC motor; terminal 4 is the ground terminal .

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(1) The coolant continuous pump (V51) mentioned in the introduction of Volkswagen's third-generation EA888 engine water pump is an electric auxiliary water pump. Its function is to assist the heat dissipation of the cylinder head and turbocharger. There are also The electric auxiliary water pump used for the heat dissipation of the heating system and the battery coolant system, but the core coolant circulation power source of this type of engine is still a mechanical water pump, and the BMW engine electronic water pump is the engine's core coolant circulation power source. Its structure and The control logic is far more complicated than the electric auxiliary pump.

(2) Common faults of BMW engine electronic water pump include long running, no running, insufficient speed, etc., and related fault codes will be stored in the engine control unit, such as the fault code "20A701 Engine Cooling System: Coolant pump speed is out of tolerance" Etc., the cause of failure is mostly the damage of the electronic module inside the electronic water pump. The electronic water pump needs to be replaced during maintenance, and the air in the cooling system should be exhausted according to specific steps: add coolant from the replenishment tank and fill it to the lower edge of the replenishment tank; turn on the ignition switch, set the air conditioner temperature to the highest, and set the blower Set to the lowest gear; depress the accelerator pedal to the end and keep it for at least 10 seconds, and do not start the engine. At this time, the electronic water pump starts to run, and the air in the cooling system is discharged from the replenishing tank.