By Bob Yu | 25 February 2021 | 0 Comments

Engine cooling water pump structure and supplier

The engine cooling water pump is the heart of the automobile engine cooling system. Its function is to increase the working pressure of the coolant in the circulating system, maintain the coolant circulation between the relevant parts of the engine, and prevent the engine from overheating. According to the different supporting requirements and working conditions, the engine cooling water pump has a centrifugal pump, a vortex pump, a rotary positive displacement pump, etc. Due to the limitation of space size, a single-stage centrifugal pump consisting of a water inlet chamber, an impeller and a water outlet chamber is usually used. The structure has the characteristics of small size, light weight, large water supply, simple structure, etc., and is the most widely used structure type. A typical centrifugal cooling circulating water pump is mainly composed of a pump body, an impeller, a bearing, a water seal and a pulley.
There are many parts around the engine cooling water pump, and its structural design must comply with the overall layout requirements of the engine, so that the direction of the flow path of the water pump, the shape and section of the volute, the layout of the water pump inlet and outlet, the impeller inlet structure and the basic size are determined It is often difficult to meet the normal hydraulic design requirements, which directly affects the improvement of operating performance including efficiency. The water inlet chamber structure of the engine cooling water pump is divided into straight cylinder type or spiral shape, and the water outlet chamber structure is spiral shape and is integrally cast with the engine. The structural geometric parameters of the impeller have a decisive influence on the performance of the water pump. The engine cooling water pump generally adopts a semi-open impeller structure without a front cover.
The performance curve is used to express the pump’s conversion characteristics of water flow energy under different working conditions, and is the external manifestation of the internal flow law of the pump. Like ordinary centrifugal pumps, the constant-speed characteristic curve of the engine cooling water pump is the relationship curve between flow and head, flow and efficiency, and flow and power at a certain speed. It can intuitively describe the operating performance of the engine cooling water pump at a constant speed. However, because the engine cooling water pump rotates continuously when it is working, the speed characteristic curve of the water pump must also be given. The variable speed characteristic curve of the engine cooling water pump mainly maps the flow, head and power curves corresponding to different speeds, reflecting the energy conversion characteristics at different speeds. In order to more intuitively reflect the comprehensive performance of the engine cooling water pump, sometimes it is necessary to draw the two performance curves on the same graph to represent their performance parameters.
Because the engine cooling water pump has the special characteristics of high working water temperature (75~85℃), wide range of rotation speed (2000~5000r/min), and overall limitation of the structure size, compared with ordinary water pumps, the water pump has a complicated design of the inlet and outlet flow passages. The flow direction and cross-sectional shape of the inlet and outlet liquids change drastically, which increases the hydraulic loss and reduces the efficiency. At the same time, engine cooling water pumps are more prone to cavitation under high temperature, high speed, and large flow conditions. At the same time, the series flow of the gap at the top of the semi-open impeller causes the squeezing of the main flow and the increase of the flow velocity in the impeller flow path, which makes the impeller steam Corrosion characteristics worsen, which seriously affects the normal operation of the cooling system and greatly shortens the service life of the cooling water pump. The special working environment and matching conditions determine that the design of the engine cooling water pump is different from the ordinary centrifugal pump.
In summary, a typical engine cooling water pump is a special application of a single-stage centrifugal pump in automobiles, with a simple type and a complex structure. Due to the severe limitation of the space size of the engine cooling water pump and the harsh operating environment, its efficiency is low and severe cavitation damage occurs. Therefore, it is very important to deeply study the relationship between efficiency and the structural parameters of engine cooling water pump, and to discuss the key factors restricting the development of engine cooling water pump.

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