The engine cooling system of the engine is one of the six systems, its function is to absorb part of the heat of the heated part distribute out to ensure that the engine is operating at the optimum temperature state.
1. Composition cooling system
during the entire cooling system, the cooling medium is a cooling fluid, the main components include a thermostat, water pump, water pump belt, radiator, fan, water sensors, the accumulator, the heating apparatus (similar to the heat sink).
1) Coolant
Also known antifreeze coolant, liquid rust preventing from icing additives and metallic additives and water. It needs to have antifreeze, corrosion resistance, thermal conductivity, and without deterioration of performance. Now often used as a main glycol component, plus added corrosion antifreeze and water. Coolant water is preferably soft water to prevent scale generation engine water jacket, the heat transfer resulting blocked, engine overheating. Boiling water was added while increasing the antifreeze coolant, additional effect can serve to prevent premature boiling of the coolant. Further, the cooling liquid also contains a foam inhibitor, can inhibit the air pump impellerFoam under agitation, water walls impede heat.
2) Thermostat
Introducing the cooling cycle, it can be seen thermostat is decided to go “cold cycle”, or “normal cycle” . Thermostat at 80 deg.] C after opening, the opening degree of maximum 95 ℃. The thermostat can not be closed, will cycle from the start into “normal cycle”, thus causing the engine can not reach or can not reach the normal temperature as quickly as possible. Thermostat does not turn on or turn inflexible, unable to make the coolant circulation through the radiator, causing the normal high temperature is too high, or when. If the thermostat does not open due to the overheating caused by temperature and pressure of the upper and lower radiator hose will be different.
3) Pump
Function
is to pump the pressurized coolant, which is circulated in the cooling system to ensure that the. Pump failure typically cause leakage of the damage to the seal, the rotating bearing fault or abnormal sound. In the event of engine overheating, the first should be noted that the water pump belt, check the belt broken or loose.
4) heat sink
to
engine operation, coolant flows in the radiator core, the outside air through the radiator core, due to the heat of the coolant air the heat and cold. Another important part of the small radiator, radiator cap is, this small parts can easily be overlooked. Varies with temperature, coolant can “thermal expansion”, the radiator is expanded due to the increase in coolant pressure and, to a certain internal pressure, the radiator cover is opened, the coolant flow to the reservoir tank; when the temperature reduced, the cooling liquid back into the radiator. If the coolant in the reservoir tank unabated, there radiator level decreases, then there is no work radiator cap! However, when running at the slow and place;
5) cooling fan
In normal driving, the high-speed air stream has sufficient heat, the fan is generally not work at this time , the fan may be rotated co radiator cooling. Fan start control by the water temperature sensor.
6) temperature sensors
In fact, the temperature sensor is a temperature switch, when the engine inlet water temperature exceeds above 90 ℃, the water temperature sensor will turn on the fan circuit . If the normal cycle, and the temperature rises, the fan does not work, the water temperature sensingAnd should you need to check the fan itself.
7) the reservoir tank
The reservoir tank is complementary change “thermal expansion” and the buffer coolant, so do not add liquid overfill. If the reservoir tank is completely empty, it can not only increase the liquid in the tank, the heat sink need to open the cover and add check the fluid coolant, the accumulator otherwise lost function.
8) heating means
In the vehicle heating system, generally less problems. As can be seen from the circulation to reports, this is not circulating thermostat control, so cold car turn up the heat, this cycle is warming the engine will have a slightly delayed impact, but the impact is really small, it does not have to let the engine warm and people chilled. It is because of the characteristics of this cycle occurs in case of emergency overheating engine, open the windows, heating to maximum, to cool the engine would certainly help.
2. The function of the cooling system
to
of the engine, the gas temperature in the cylinder up to 1727 ~ 2527C, if not promptly cooled, high temperature will cause engine components, especially the direct parts in contact with high-temperature gas, due to thermal expansion affecting the normal with the gap, resulting in movement of member hindered even stuck. In addition, the high temperature will result in a decline in the mechanical strength engine parts, such as lubricating oil out of action. The main function of the cooling system is part of the heat absorption part of the heat dissipated in time, to ensure that the engine is operating at the optimum temperature state. Cooling medium can be divided according to different cooling air and water, if the temperature in the hot part of the engineMeans the amount of direct and scattered into the atmosphere for cooling air system is called. And this heat to the cooling water to pass, and then scattered into the atmosphere and cooled with water-based cooling device is called. As the water-cooling system to cool uniform, effective, and less engine noise operation, is currently widely used on automobile engine is water-cooled system.
3. cooling cycle
[123 ] since most vehicles are water-cooled engine, the paper describes a cooling cycle of the main water-cooled engine. In the cooling cycle water-cooled engines can be divided into “small cycles” and “big cycle.” Refers only small circulation of cooling water circulating in the engine, and a cycle of cooling water is circulated between the engine and the heat exchanger (water tank). ? Why should there be a large circulation and small cycles it is mainly because of low temperatures in the cold car engine, this time a small amount of cooling water for the small cycles within the engine, the engine quickly reaches its operating temperature; once the engine reaches operating temperature, control large , the conversion of small cycles the temperature control valve (commonly known as water turtles) will open, so that the cooling water flows within the tank to allow the air to go tropical, the higher the engine temperature, the degree of opening of the greater water turtles, the flow rate of the cooling water is also the larger, well away more heat. Circulation of cooling water by the water pump is driven, the water pump is driven by the operation of the engine, so that the higher the engine speed when the operation efficiency of the water pump is also higher.
The characteristics of the cooling liquid
The coolant is pure water tank with fine modulation by a certain percentage, the tank can be refined to increase the boiling point of the cooling water. A boiling point of pure water at normal temperature and pressure is 100 deg.] C, once the engine temperature is too high, the cooling water boils to become steam, the water in the gaseous state thermal convection coefficient much lower than the liquid, the gas with water vapor hardly take the heat engine, when the engine temperature rises rapidly damage the engine. So raise the boiling point of the cooling water tank fine water to ensure that the coolant at high temperatures is still liquid in order to take away the heat generated by the engine.