Fig. 7- 1 is a schematic diagram of the forced circulating water cooling system. It has perfect cooling regulation and control functions. When the engine is cold started, the working temperature is low, the main valve of thermostat 4 is closed and the auxiliary valve is opened. The cooling water enters the water branch pipe 7 from the water pump 8, flows directly to the water pump through the water jacket 6 (without radiator 12) and the auxiliary valve of the thermostat, and enters the water branch pipe after being boosted by the water pump. This is the so-called small circulation water cooling system. The temperature of the engine will rise rapidly, when the water temperature rises to 353K(80 degrees); At this time, the main valve of the thermostat is opened and the auxiliary valve is closed. The cooling water in the water jacket flows from the upper water outlet into the upper water storage tank 1 through the thermostat main valve, and after being cooled by the radiator 12, it enters the lower water storage tank 10, and is sucked into the water pump from the sewer pipe for pressurization, and then pumped into the branch pipe 7. This is called the great cycle of the cooling system. The cooling system also uses the strong suction of the fan 3 to make the air pass through the radiator at high speed from front to back, such as the heat dissipation capacity of fast water.
Schematic diagram of forced circulating water cooling system/autoepic/autoepic _ text.asp? id= 1 144
In order to improve the cooling intensity of water and overcome the overflow and evaporation in the cooling process, a closed pump circulating water cooling system has been adopted in automobiles at present.
Fig. 7-2 is a schematic diagram of the circulation route of Shanghai Santana engine cooling system. When the engine is cold or the temperature is low, the path through which the coolant flows is a small cycle. In this way, the coolant will not flow through the radiator. Only when the temperature of the coolant reaches a certain value, the coolant enters a large cycle. This can reduce the heating time of the engine and effectively reduce the energy loss and parts wear. The cooling circulation path is controlled by a thermostat located at the lower part of the water pump. When the temperature of the coolant reaches -358K(85 degrees), the thermostat valve opens, and the coolant begins to flow through the radiator and enter a large cycle. When the temperature of the coolant reaches 378K( 105℃), all valves of the thermostat are opened, which enhances the circulating cooling capacity of the coolant and controls the temperature rise of the coolant.
The picture shows the circulation route of Shanghai Santana engine cooling system. id= 1 144
Advantages of water-cooled engine! (Take motorcycles as an example)
Spring breeze water-cooled motorcycle has high power and low fuel consumption.
The air-cooled engine is limited by its structure, so it is difficult to get uniform and effective cooling in the combustion chamber with the most serious thermal load, and only low compression ratio can be used to limit the maximum power it can emit. However, the spring breeze water-cooled engine is equipped with cooling channels around the combustion chamber to ensure that the wall temperature of the combustion chamber is uniform and appropriate, and even if a high compression ratio is adopted, knocking will not occur. Therefore, the water-cooled engine can achieve high combustion efficiency, high engine power and low fuel consumption. Take spring breeze water-cooled 152MI engine and air-cooled GY6 engine as examples. The cylinder diameter and working volume of the two engines are the same, and the compression ratios are 10.3: 1 and 9.2: 1 respectively. The maximum power spring breeze water-cooled 152MI engine is larger than GY6 engine 1kW, and the fuel consumption is lower 1KW.
Spring breeze water-cooled motorcycle has low noise.
The cooling around the cylinder of air-cooled motorcycle engine is uneven, with low temperature on the windward side and high temperature on the other side. In order to prevent the engine from pulling in the running process, it is necessary to adopt a larger cylinder gap between the cylinder and the piston, which will increase the mechanical noise, and the noise of the cooling fan and the cowl will inevitably increase. The cylinder of spring breeze water-cooled engine cools evenly, so a smaller cylinder gap can be used. The combustion chamber and cylinder are surrounded by coolant, and the cooling water jacket can absorb and block engine combustion noise and mechanical noise. Therefore, we say that the spring breeze water-cooled motorcycle is a low-noise motorcycle.
Spring breeze water-cooled motorcycle has low emission and environmental protection.
In recent years, the European Union, the United States and China have successively promulgated more and more stringent motorcycle emission standards. Whether it can meet the emission regulations has become a key factor for motorcycles to enter the domestic and foreign markets. By optimizing combustion chamber design, selecting compression ratio, matching fuel supply system, secondary air intake and three-way catalysis, Feng Chunshu's cold motorcycle can reduce the emission of various harmful components. At present, all types of Feng Chunshu cold motorcycles can meet the requirements of Euro II emission regulations, and research work is being carried out to meet the requirements of Euro III emission regulations in the near future.
Spring breeze water-cooled motorcycle has good reliability and long service life.
When the motorcycle engine burns the mixture, it will generate a lot of heat, and the highest temperature of the gas in the combustion chamber can reach above 2000℃. It is necessary to reduce the working temperature of parts through the cooling system to ensure the reliability and durability of the engine. The heat dissipation of air-cooled engine is directly transferred from metal to air, and its heat transfer coefficient is much smaller than that of metal to water, so the cooling effect of air-cooled engine is worse than that of water-cooled engine, and the cooling is uneven. When the air-cooled motorcycle works under heavy load for a long time, especially when climbing a long slope at a low speed, it should not cause excessive temperature of engine parts and oil, poor lubrication, and serious accidents such as piston ring jamming, failure, piston cylinder pulling and cylinder head cracking will occur. Compared with air-cooled motorcycles, spring breeze water-cooled motorcycles have the advantages of good cooling effect and uniform cooling. Under various use conditions, the piston, piston ring, cylinder, cylinder head and the existing temperature can be guaranteed to be within the allowable range of normal operation, and all components can work in a good lubrication state and temperature, thus ensuring the reliability of the engine and prolonging the service life of the engine.