ELECTRIC WATER PUMP

■   Automobile electric water pump is a kind of water pump used on automobiles and equipped with electronic control drive unit, and is primarily composed of overcurrent unit, motor unit, and electronic control unit.
■   As a brand new water pump, electric water pump takes piezoelectric material as the power unit and achieves electronization from control to drive thoroughly, and its electronic integrated system controls the liquid transfer fully to realize adjustable and precise liquid transfer.
■   Electric water pump primarily comprises pump casing, impeller, seal ring, engine casing, electrical plug, motor assembly, bearing, rotor, controller, controller base, back cover, and fixed bolt.

■   Automobile electric water pump pressurizes liquid coolant, which thus flows circularly in the cooling system and passes through various components of radiator and engine cylinder to take away heat and prevent engine overheating.

■   Inside the engine block, there is a water jacket for coolant circulation, which is connected to the radiator (commonly known as the water tank) located at the front of the vehicle through hoses, forming a coolant circulation system. A water pump is installed at the engine outlet and driven by the fan belt. It pumps the hot coolant out of the engine block water jacket and circulates the cold coolant into the engine.
■   A thermostat is set beside the water pump. When the automobile starts (cold status), the thermostat would not be turned on, so cooling water would not go through the water tank, but only circulate inside the engine (called “small circulation”). After the engine temperature rises above 80℃, the thermostat would be turned on, so hot water from the engine would be pumped into the water tank. When the automobile drives forward, cold air blows over the water tank and takes away heat. Only when coolant circulates can the temperature of the engine get down.

■   PPS is the commonly used material for the components of electric water pumps. It is resistant to high temperature and corrosion, flame-retardant, etc. As the special engineering material that is most cost-effective, it is mainly characterized by high temperature resistance, dimensional stability and resistance to deformation, excellent electrical properties, resistance to chemical corrosion, UL94V-O flame retarding, good electrical insulation property and hydrolysis resistance; furthermore, modified PPS has multiple characteristics, including high liquidity, high toughness, high wearing performance, high strength, coolant resistance, high CTI, and low dielectric properties, ensuring the working reliability of electric water pump. 
■   Strong bonding strength of water pump casing and metals, high weld wire strength (avoid product cracking in storage), hydrolysis resistance; PPS used can meet material requirements; integrative injection moulding, easy to process, strong structural stability, not easy to deform.
■   Impeller is injection moulded with PPS. It is mainly characterized by high strength, flame and high temperature resistance, high toughness, dimensional stability, and long service life. The water pump rotor is injection moulded with PPS and has high wear resistance, high strength, and other features.

■   Adopting brushless DC motor; compact in structure, small in volume and lightweight. 
■   Resistant to extremely cold and hot environment temperatures, convenient to use, impact resistant, and highly resistant to shock. 
■   Durable permanent magnet rotor and high-precision ceramic bearing, powerful, flexible to control, safe and reliable. 
■   Advanced magnetic drive technology, static seal, no leakage, strong electromagnetic compatibility, low noise, good performance, stable operation. 
■   Polarity protection, overload protection, locked-rotor protection, low energy consumption, high efficiency. Professional automobile waterproof terminal, waterproof grade IP67. 
■   Specially designed rubber mounting bracket can be well used under automobile’s vibration operation conditions. 
■   Specially designed electronic components are suitable for auto power supply’s peak voltage or unstable voltage in its power supply mode. 
■   Accurately conveying liquid, ideal for fields requiring quantitative conveyance and quantitative control of liquid; liquid conveying is speed-governed. 
■   Good corrosion resistance: PPS GF is normally used; long service life and continuous working for over 20,000 hours. 
■   Wide operating voltage, usually from 9V to 33V; resistant to high temperature, available for working under -40℃-120℃ normally. 
■   Having passed parking heating test, automobile coolant circulation test, engine cooling system test, automobile thermal cycle test, electronic automobile water cycle test, automobile engine cooling system test, normal hot water cycle test. 
■   Electric water pump has the self-priming function. Self-priming function: When water pump’s suction pipe is fully charged with air, water pump’s working would form negative pressure (vacuum); water below the suction inlet is lifted by atmospheric pressure, and water would be discharged out of the drain end of water pump. There is no need to add “leading water” before this process. The micro water pump with this self-suction capacity is called “micro self-priming pump”.

 Working Principle

■   Under motor’s circular motion, mechanical device enables the diaphragm inside water pump to make reciprocating motions and compress and stretch the air inside pump chamber (fixed volume). 
■   Under the action of check valve, positive voltage would be formed at the outlet. 
■   Vacuum would be formed at the pump outlet, resulting in pressure difference with the outside atmospheric pressure. Due to this pressure difference, water is pressed into water inlet and discharged out of water outlet. 
■   Motor transfers kinetic energy; water is sucked and discharged constantly to form steady flow. 

 Maintenance Tips

■   Check ball bearing. For example, if its inner or outer bush is worn, loose, or the ball is worn or there are spots on the surface, it’s necessary to replace. If such a situation occurs, but the corresponding component can be used, please clean the bearing with gasoline or kerosene first and then spread butter on it and store the bearing. 
■   Check impeller for any crack or pore, or looseness of its fixing nut. If any damage is observed, the impeller shall be repaired or replaced. Check the clearance around the impeller’s wearing ring. If the clearance exceeds the specified value, the impeller shall be repaired or replaced. 

■   Try to control the water pump’s flow and head within the stated scope whenever possible to enable the water pump to work at the maximum efficiency point and obtain the energy-saving effect.
■   During working, water pump’s maximum temperature shall not exceed 80℃.
■   Lubrication of the mechanical seal shall ensure that it is free from solid particles, and it’s strictly forbidden for the mechanical seal to work under dry grinding.