In the cylinder block of a car engine, there are multiple water channels for the circulation of cooling water, which are connected to the radiator (commonly known as the water tank) placed at the front of the car through water pipes to form a large water circulation system. The water outlet on the engine is installed. There is a water pump, driven by the fan belt, to pump out the hot water in the engine block waterway and pump in the cold water. There is a thermostat next to the water pump. When the car is just started (cold car), it is not turned on, so that the cooling water does not pass through the water tank, but only circulates in the engine (commonly known as the small cycle), until the temperature of the engine reaches 95 degrees or more When it is turned on, the hot water in the engine is pumped into the water tank, and the cold wind when the car is moving forward blows through the water tank, taking away the heat.

structure
Centrifugal water pumps are widely used in automobile engines. Its basic structure is composed of water pump housing, connecting plate or pulley, water pump shaft and bearing or shaft bearing, water pump impeller and water seal device and other parts, which are the main components of the automobile.

Automobile micro water pump

working principle
The engine drives the water pump bearing and impeller to rotate through the pulley, and the coolant in the water pump is driven by the impeller to rotate together, and is thrown under the action of centrifugal force.

Automobile antifreeze circulating water pump

To the edge of the water pump housing, a certain pressure is generated at the same time, and then it flows out from the water outlet or water pipe. The pressure at the center of the impeller is reduced due to the cooling liquid being thrown out. The cooling liquid in the water tank is sucked into the impeller through the water pipe under the action of the pressure difference between the inlet of the water pump and the center of the impeller to realize the reciprocating circulation of the cooling liquid.

The bearing supporting the water pump shaft is lubricated with grease, so it is necessary to prevent the coolant from leaking into the grease to cause the grease to emulsify, and at the same time to prevent the leakage of the grease. The sealing measures of the water pump to prevent leakage include water seal and gasket. The water seal dynamic seal ring and the shaft are installed between the impeller and the bearing through an interference fit, and the water seal static seal seat is tightly press-fitted on the housing of the water pump to achieve the purpose of sealing the coolant.

The water pump housing is connected to the engine through a gasket and supports moving parts such as bearings. There is also a drain hole on the water pump housing, located between the water seal and the bearing. Once the coolant leaks through the water seal, it can be drained from the drain hole to prevent the coolant from entering the bearing cavity to damage the bearing lubrication and cause the parts to rust. If the coolant still leaks after the engine is stopped, it indicates that the water seal has been damaged.

Water pump drive
It is generally driven by the crankshaft of the engine through a V belt. The drive belt is looped between the crankshaft pulley and the water pump pulley. The water pump shaft rotates as soon as the crankshaft rotates, and the water pump shaft drives the impeller to rotate, thereby realizing the conversion of mechanical energy into hydraulic energy.

The impeller is the core of the pump. The movement of the impeller itself is very simple, just rotating with the shaft. However, due to the action of the blades, the movement of the liquid in the impeller is very complicated; on the one hand, it makes implicated motion with the rotation of the impeller, and on the other hand, it is continuously thrown out from the rotating impeller under the drive of the blade, that is, it moves relative to the impeller. Therefore, the outer diameter of the impeller, the height and angle of the impeller blades, and the gap with the water pump casing directly affect the performance of the water pump.