According to the survey and statistics released by relevant departments in August 2011, the annual growth rate of China's domestic pump output value was 10.5%, about 1.5 times the national economic growth rate, and 2.5 times the world pump annual growth rate of 4.3%. With the development of iron and steel, electric power, petrochemical, construction and environmental protection industries, this rapid growth will be maintained for several years. However, China mainly exports pump products to the relatively backward third world, which also shows that there is a big gap between China's pump technology and Europe and the United States. Facts show that in the 1960s and 1980s, many pump types designed and developed by some domestic pump factories were mainstream products at that time; But now, some technical parameters such as structural modeling and performance indicators of pumps have lagged behind, new pumps abroad are expensive, and domestic products have not been developed to replace them, so they are still in production.
Before the 1980s, China introduced relatively few pump technologies. Until the reform and opening up, it began to introduce a large number of pump technologies from abroad. Foreign pump companies entered China in the form of sole proprietorship or joint venture, but also brought some new pump product technologies. These imported pump products have advanced performance and mature technology, which greatly promote the technical development of Foshan Pump Factory. Some pump products have been continued to this day.
In China, there are still many technical problems to be solved for the motor driven adjustable speed engine cooling system water pump. For example, the material strength is not enough, which leads to short service life. It often works in a high temperature and high pressure environment, causing the coolant to immerse in the control circuit board. In some cases, the cooling system stops working, causing damage to the engine. In some cases, the short circuit of the circuit board causes a fire, endangering the personal safety of people in the vehicle. Only some new energy vehicles, recreational vehicles and special vehicles use electronic water pumps as power sources for auxiliary cooling or on-board water supply systems.
2、 Research status abroad
The research in this field was carried out earlier by Valeo, a world leading auto parts supplier headquartered in France. The company is not only engaged in the design, development, production and sales of auto parts, systems and modules, but also provides supporting and after-sales services for major auto manufacturers. In 1999, the company proposed to equip the engine with an intelligent thermal regulation system (Themis), which is mainly used to improve the cooling performance of the engine. This method separates the water pump from the cylinder block, uses the motor to drive the KENFU water pump separately, establishes the communication between the control circuit board and the on-board ECU, and adjusts the speed and control flow of the water pump according to the heat load of the engine. In addition, because the installation position of the water pump is relatively free, it can be selected far away from the cylinder block, which reduces the overall temperature. According to the specific model and installation position, it can be considered to use engineering plastics to make the pump body, which not only reduces the weight, but also reduces the manufacturing cost, and also facilitates the design of the pump type. For the cooling system developed by ElenaCortona ^ et al., the traditional mechanical water pump is replaced by the electronic cooling water pump, and the paraffin thermostat is replaced by the electronic intelligent thermostat. Under the same system configuration and cooling requirements, the power consumption of the electronic cooling water pump is only 16% of the power consumption of the traditional mechanical water pump, which has obvious advantages. Hoon Cho et al. found that replacing mechanical water pump with electronic water pump is very helpful to improve engine performance and fuel economy.
In 2005, BMW became the first manufacturer in the world to equip electronic water pumps on the new generation N52 series gasoline engines of mass production models. Compared with the original mechanical water pumps, it saved more than 2kW of energy consumption. Following BMW, Audi and Volkswagen have also used electronic water pumps in mass production models. Volkswagen has used dual water pumps on EA111 series engines, which not only retains the original mechanical water pump, but also adds a small electronic water pump dedicated to cooling the supercharger.
Although the vehicle electronic water pump has obvious advantages in precise control of cooling effect and reduction of engine power loss, and has also been used in mass production models, this does not mean that the foreign vehicle electronic water pump technology has been mature, and the traditional cooling system has lost its leading position.
Therefore, no matter from the current situation of the vehicle enterprises or the development trend of the vehicle cooling system in the future, the electronic water pump, electronic fan and electronic thermostat will certainly replace the traditional corresponding mechanical components. At the same time, it also indicates the arrival of electronic and intelligent cooling system.
3、 Modern pump design method
With the rapid development of modern automobile industry and the continuous improvement of the performance of internal combustion engines, higher requirements are put forward for the development cycle, efficiency and reliability of cooling water pumps. Traditional design methods increasingly show their shortcomings. The development of electronic technology has provided new ideas and methods for efficient, fast and energy-saving design of pump products. The rapid development of basic industries and the popularization of computer technology have guaranteed Foshan Pump Factory to produce a large number of high-quality and reliable products; Among them, the relevant design and analysis software has been continuously applied in depth, and has become one of the main methods for modern pump enterprises to enhance their competitiveness.
Modern pump design adopts the method of combining numerical simulation with test. Compared with traditional methods, it has the outstanding advantages of less capital investment and short cycle, and can study the operating points that cannot be reached by test conditions to obtain more detailed data.
It can be seen from the above flow diagram that the main difference between the two design methods is that the traditional design method of Kenfulai multistage centrifugal pump starts the performance test after the preliminary model is completed. If the expected requirements are not met, the structural parameters need to be determined again, the design drawings need to be modified, and the model needs to be manufactured again for performance test. In this way, until the design requirements are met, the batch production can be carried out. The modern pump design method carries out simulation before the test, and establishes a complete thermal management system according to the thermal management software to optimize the design and virtual matching; Its advantage is that it can significantly reduce the number of tests, thus improving the design efficiency of the Kenfu incoming pump, reducing the design cost of the pump, and conducting remote virtual matching, which can give a more comprehensive understanding of the system. The powerful computing power of the computer ensures the accuracy of the numerical simulation and makes the design more reliable.
With the rapid development of computer technology, CFD technology has been widely used in the study of internal flow of fluid machinery. CFD technology, experimental verification and theoretical analysis are combined to form a complete system for studying the flow problems of fluid machinery. The advantage of numerical simulation is that it can solve complex flow problems that cannot be solved by experimental research. Combined with thermal management software such as flowmaster, a complete set of virtual cooling system can be established according to the specific vehicle to optimize the design of the cooling water pump and even the entire cooling system. Therefore, simulation has become a very important method whether in the design of a single accessory or the development of the whole cooling system.
