What is the function of a thermostat? How does it work?

The thermostat, also known as the "water bladder", is used to open or close the valves of the large and small circulation channels according to the water temperature, and control the engine coolant to flow according to the large or small circulation. When the engine is cold, the water tank is turned off, and the water tank water circulates in the engine waterway (i.e., "small circulation"), which is not cooled by the water tank, so the water temperature can quickly rise to the normal working temperature of the engine. When the temperature continues to rise, the water tank is turned on, and the tank water can flow into the tank, thus controlling the temperature from rising.

BMW's water tanks are divided into two types, one is mechanical and the other is electronic. Nowadays, the common models are basically electronic. During the maintenance inspection, if it is found that the electronic water tank has a fault memory and currently exists, it is generally recommended that the guest replace it!

The following legend shows an electronic water ursule. The picture above shows that when the car is cold, the water tank is turned off and the water tank water is circulated in the engine waterway.

The thermostat, also known as the thermostat, is to automatically adjust the amount of water entering the radiator according to the temperature of the cooling water, change the circulation range of the water, adjust the heat dissipation capacity of the cooling system, and ensure that the engine works within the appropriate temperature range. The thermostat must be kept in good technical condition, otherwise it will seriously affect the normal operation of the engine. If the main valve of the thermostat is opened too late, it will cause the engine to overheat; If the main valve is opened too early, the engine warm-up time will be prolonged, and the engine temperature will be too low.

At this time, it can be judged whether the working condition of the thermostat is good, when the engine starts to run cold, if there is still cooling water flowing out at the water inlet pipe of the water chamber of the water tank, it means that the main valve of the thermostat can not be closed; When the engine cooling water temperature exceeds 70 degrees Celsius, and there is no cooling water flowing out of the inlet pipe of the water tank upper water chamber, it means that the main valve of the thermostat cannot be opened normally, and it needs to be repaired. The thermostat inspection can be carried out on the car in the following ways:

Check after the engine starts: open the radiator water nozzle cover, if the cooling level in the radiator is quiet, it means that the thermostat is working normally, otherwise, it means that the thermostat is working abnormally. This is because, when the water temperature is lower than 70, the thermostat expansion cylinder is in a contracted state and the main valve is closed; When the water temperature is higher than 80, the expansion cylinder expands, the main valve gradually opens, and the circulating water in the radiator begins to flow.

When the water temperature gauge indicates below 70, if there is water flowing at the radiator inlet pipe and the water temperature is warm, the main valve of the thermostat is not closed tightly, so that the cooling water is prematurely circulated.

Check after the water temperature rises: at the beginning of engine operation, the water temperature is thousands and fast; When the water temperature gauge indicates 80, the heating rate slows down, indicating that the thermostat is working normally. On the contrary, if the water temperature has been rising rapidly, when the internal pressure reaches a certain level, the boiling water suddenly overflows, indicating that the main valve is stuck and suddenly opened.

When the water temperature meter indicates 70 -80, open the radiator cover and the radiator water discharge switch, feel the water temperature with your hand, if it is hot, the thermostat is working normally; If the water temperature at the radiator inlet is low, and there is no water outflow or little water at the inlet pipe of the radiator upper water chamber, it means that the main valve of the thermostat cannot be opened.

Thermostats that are stuck or not tightly closed should be removed for cleaning or repair, and should not be used immediately.

A thermostat is a valve that controls the flow path of the coolant. It is an automatic temperature control device, usually containing a temperature sensing component, which turns on and off the flow of air, gas, or liquid by means of thermal expansion or cold contraction.

The function of the thermostat is to adjust the engine to be cooled through the heat dissipation tank. When the outlet water temperature, especially during the start of the vehicle reaches 83°3°, the thermostat valve is completely neutral, it can make the engine temperature rise rapidly, open and close the bypass. All the water outlet is temperature reduced to reduce the wear of the cylinder.

The working principle of the valve is discharged or flowed through the heat dissipation water tank: when the cooling water is at a low temperature, the thermostat is cooled.

The double thermostat also has a function is energy saving, for the electronic control diesel engine, the water temperature is a very important fuel injection reference signal, the engine itself has a suitable working temperature, too high and too low are not good, the use of double thermostat can achieve more accurate water temperature regulation and control, which helps to save energy and reduce fuel consumption. In addition, some vehicles use a double thermostat, which allows the cylinder block and cylinder head to be controlled separately. If it is helpful to you, I hope you can adopt it, thank you.

The function of the thermostat is to heat up as soon as possible, so that the engine can reach the best working temperature, and at the same time, the heating system will have the working temperature as soon as possible; Secondly, when the engine temperature is too high, it has the function of controlling the size and circulation of the cooling system, which plays the role of heat dissipation and cooling.

1. Automobile thermostat.

The thermostat automatically adjusts the amount of water entering the radiator according to the temperature of the cooling water to ensure that the engine works within the appropriate temperature range, which can play a role in saving energy consumption. Because the engine is very fuel-intensive at low temperatures, and the damage to the car is greater, including easy to produce carbon deposits and bring a series of problems.

2. Explanation of terms.

An automotive thermostat is a valve that controls the flow path of engine coolant.

3. Role. The thermostat must be kept in good working condition, otherwise it will seriously affect the normal operation of the engine. If the thermostat is opened too late or even cannot be opened, it will cause the engine to overheat; If it is turned on too early, the engine warm-up time will be prolonged, and the engine temperature will be too low.

Thermostat is an automatic temperature control device, usually containing a temperature sensing component, which turns on and off the flow of coolant by expansion or cold contraction, that is, automatically adjusts the amount of water entering the radiator according to the temperature of the cooling liquid, and changes the circulation range of the coolant to adjust the heat dissipation capacity of the cooling system.

At present, the thermostat used is mainly a wax thermostat, which is controlled by the paraffin wax inside the coolant circulation mode through the principle of thermal expansion and cold contraction. When the cooling temperature is lower than the specified value, the refined paraffin in the thermostat thermostat is solid, the thermostat valve closes the channel between the engine and the radiator under the action of the spring, and the coolant returns to the engine through the water pump for small circulation in the engine. When the coolant temperature reaches the specified value, the paraffin wax begins to melt and gradually becomes liquid, the volume increases and compresses the rubber tube to make it shrink, and the rubber tube shrinks at the same time to act on the push rod with an upward thrust, and the push rod has a downward reverse thrust to the valve to open the valve.

At this time, the coolant flows back to the engine through the radiator and thermostat valves, and then through the water pump, where it is circulated. Most of the thermostats are arranged in the cylinder head outlet pipeline, which has the advantage of simple structure and easy to discharge air bubbles in the cooling system; The disadvantage is that the thermostat often opens and closes when working, resulting in oscillation.

When the engine working temperature is low (below 70 °C), the thermostat automatically closes the passage to the radiator, and opens the passage to the water pump, the cooling water flowing out of the water jacket directly enters the water pump through the hose, and is sent to the water jacket through the water pump for circulation, because the cooling water does not dissipate heat through the radiator, the engine working temperature can rise rapidly, and this cycle route is called small circulation. When the engine working temperature is high (above 80 °C), the thermostat automatically closes the channel leading to the water pump, and opens the channel leading to the radiator, and the cooling water flowing out of the water jacket is sent to the water jacket by the water pump after heat dissipation by the radiator, which improves the cooling intensity to prevent the engine from overheating. When the engine operating temperature is between 70 and 80 °C, large and small cycles exist at the same time, that is, part of the cooling water is in large circulation, while the other part of the cooling water is in small circulation.

The function of the car thermostat is to be in a closed state before the temperature of the car reaches the normal temperature, and then the coolant of the engine is returned to the engine through the water pump for small circulation in the engine, so that the engine can heat up quickly. When the temperature exceeds normal, it can be turned on, allowing the coolant to circulate through the entire radiator circuit of the tank, so as to dissipate heat quickly.