Small components play a big role, and knowledge popularization of thermostats

2023-07-25 09:12:08

Among the components of a diesel engine, there is a relatively small component called a thermostat. I believe many truck drivers do not understand its function or how to maintain it. Today, the truck hodgepodge will bring you knowledge popularization.

The thermostat is an on/off valve in the engine cooling system that controls the flow path. By sensing the temperature of the engine coolant, the flow path to the radiator is opened or closed, achieving dynamic adjustment of the engine temperature and allowing the engine to operate at the optimal temperature.

When the water temperature around the thermostat rises, the temperature is transmitted to the sensing wax through the body. The sensing wax expands when heated.

Due to the sealed space inside, the rubber tube is squeezed, and the rubber tube pushes the push rod. However, due to the fixed position of the push rod on the valve seat, it cannot move. Due to the reaction force, the sensing body is pushed downwards in the opposite direction, and the spring force is overcome to drive the valve away from the valve seat, forming the opening of the thermostat.

The working principle of a thermostat:

(1) At low temperatures, the main valve of the thermostat is closed, and the coolant does not pass through the radiator and circulates inside the engine.

(2) At high temperatures, the main valve of the thermostat opens and closes the small circulation, and all the coolant passes through the radiator for a large circulation.

After understanding the function and working principle of the thermostat, how do you need to maintain it in daily life?

(1) Ensure that the antifreeze is sufficient and regularly check if the antifreeze level is within the required range.

(2) Regularly check the surface of the thermostat for signs of water leakage.

In order for truck drivers to experience abnormal engine high temperatures in their daily work, the following points should be noted:

1.Maintaining cleanliness on the outside and inside of the cooling system (especially the radiator) is an important condition for improving heat dissipation efficiency. Dirt or deformation caused by collision on the outside of the radiator can affect the airflow and cause the coolant temperature to be too high. If necessary, clean or repair it.

2. Use Weichai special antifreeze coolant according to regulations to maintain sufficient coolant.

3. Reasonably operate and use the engine, do not overload the engine, and do not bang the accelerator indiscriminately.

4. The tension of the fan belt should be maintained appropriately to ensure normal operation of the fan. Loose belts affect water circulation and exacerbate wear; Excessive tightness can easily damage the bearings.

5. The thermal switch is well connected, and if it is loose, it will affect the shifting and normal operation of the fan;

6. Prevent the engine from working under heavy load and for a long time to avoid excessive water temperature; Shift gears in a timely manner when going uphill to reduce load. When a car is driven on a slope for a long time, in a low gear position, or in a high ambient temperature, attention should be paid to heat dissipation.

7. For new and overhauled engines, it is necessary to first undergo running-in, that is, under the condition of maintaining good lubrication, following the principle of low to high speed and low to high load, and carefully operating according to the running-in specifications before putting them into formal load operation.

8. According to the requirements of the user manual, correctly select the gap between the piston skirt and the cylinder liner, as well as the opening gap of the piston ring. At the same time, ensure the dimensional accuracy of the cylinder liner.

9. Maintain the normal operating temperature of the cooling water to avoid engine overheating. Before starting the engine in winter, preheating measures should be taken.

10. To maintain the lubrication system well, it is necessary to use Weichai special engine oil to prevent mechanical impurities and carbon deposits from mixing into the oil and exacerbating cylinder wear.