.
1 Engine Cooling
Introduction:
The cooling system is a function of the heated part of the heat absorbed distribute out parts, keep the engine at the optimum working temperature state. Engine cooling system are air and water points. With air as a cooling medium is called air-based cooling system; cooling fluid is referred to as a water cooling system cooling medium.
cycles:
In the cooling system, in fact, there are two cooling loops: a main loop for cooling the engine, and the other is the vehicle heating cycle. Both are in the engine cycle as the center, using the same cooling liquid.
First, the main engine cooling loop
Two main loop comprising duty cycle, i.e. ldquo; cold cycle rdquo; and ldquo; normal cycle rdquo ;. After cooling the car the car, gradually warming the engine, the temperature of the coolant system can not open the thermostat, the cooling liquid through the pump is only performed in the engine ldquo; rdquo ;, Cold object cycle of the engine as quickly as possible reach normal operating temperature. As the temperature of the engine coolant temperature is raised to the thermostat opening temperature (typically 80 deg.] C, after which the temperature), the cooling cycle begins ldquo; normal circulation rdquo ;. Coolant from the engine out of this time, after the front end of the car radiator, cooling, and then into the engine water pump.
Second, the interior heating cycle
This is a heating cycle, but for the engine, which is also a cooling circuit of the engine. After cooling liquid vehicle heating apparatus, the heat of the coolant into the vehicle, and then back to the engine. One thing is different: the cycle of uncontrolled heating thermostat, simply open heating, this cycle will begin, regardless of the coolant is cold or hot. Cooling system
automotive engine forced circulation water cooling system, i.e.,Using a pump to increase the pressure of the coolant, the coolant forced flow in the engine cycle. Cooling mainly by the water pump, a radiator, a cooling fan, the compensation tank, thermostat, an engine block and a cylinder head water jacket and ancillary devices and other components.
Analysis of the system components:
during the entire cooling system, the cooling medium is a cooling fluid, the main components include a thermostat, water pump, water pump belt, radiator, cooling fan, temperature sensor, the accumulator, the heating apparatus (similar to the heat sink).
1) Coolant: Coolant also known as antifreeze, liquid is produced water corrosion additives and additives and to prevent frost from metal. 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.
2) Thermostat: Introducing the cooling cycle, it can be seen thermostat is decided to go ldquo; rdquo ;, or cold cycle ldquo; normal cycle & rdquo;. Thermostat at 80 deg.] C after opening, the opening degree of maximum 95 ℃. The thermostat can not be closed, will cycle from the beginning to enter ldquo; normal cycle rdquo ;, 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: effect of the coolant pump is pressurized to ensure its circulation in the cooling system. 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) radiator: when the engine is operating, coolant flow in the radiator core, through the air outside the radiator core, hot coolant and heat due to the air cooling. Another important part of the small radiator, radiator cap is, this small parts can easily be overlooked. Varies with temperature, coolant can ldquo; rdquo ;, expansion and contraction due to the expansion of the heat sink device and the coolant pressure increases, to a certain internal pressure, the radiator cover is opened, the coolant flow to the reservoir tank;When the temperature decreases, the coolant flows back to the radiator. If the coolant in the reservoir tank unabated, there radiator level decreases, then there is no work radiator cap!
5) Fan: normal driving, the high-speed air stream has sufficient heat, the fan is generally not work at this time; however, slow in operation and in situ, the rotation of the fan may help to radiator cooling. Fan start control by the water temperature sensor.
6) temperature sensors: a temperature sensor is actually 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 turn, temperature sensors and fans need to check themselves.
7) the reservoir tank: a reservoir tank that is complementary to the coolant and the buffer ldquo; thermal expansion and contraction rdquo; changes, 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 system: heating means in the car, it is generally not a problem. 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, up the heat maximum, to cool the engine would certainly help.