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2025
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Truck Encyclopedia (6): Engine Big Cycle Small Cycle
I'm sure everyone has heard of big cycles and small cycles, but not many people really understand it. This article also explains to cardholders in an easy-to-understand way as much as possible.
▎ The cooling cycle should be fast and stable
为什么要快
Why is the cooling cycle faster? That's because in the early stages of engine starting, the engine must heat up quickly in order to reach the operating temperature faster, reduce fuel consumption and pollutant emissions.
Why steady
When the engine reaches the working temperature, it needs to work stably within the appropriate temperature, and it cannot be high or low. When the temperature is high, the lubricating oil will become thin and deteriorate, and it will not be able to provide a sufficient strength of the oil film; When the temperature is low, the lubricating oil is too thick, and the resistance increases, which affects fuel economy, so the engine needs a stable operating temperature.
▎ Size cycle is indispensable
In order to control the water temperature of the engine quickly and stably, the designer cleverly designed two cooling cycles for the engine cooling system, which are large circulation and small circulation.
The so-called small circulation means that the coolant only circulates in the water channel inside the engine.
The so-called large circulation is that in addition to circulating in the water channel inside the engine, it also passes through the radiator outside the engine, which is commonly known as the water tank.
The two cycle modes are switched by opening and closing the thermostat.
When Wang's car stopped for a night, the engine's thermostat was turned off, and the cooling system entered a small cycle mode as soon as the engine started.
In the small circulation mode, the coolant only circulates in the water channel inside the engine, and there is less coolant involved in the circulation, which serves the purpose of rapid heating up.
When the water temperature gradually rises, under the action of temperature, the thermostat is turned on, and the cooling system enters the large circulation mode. In the large circulation mode, the coolant will flow through the radiator of the tank, and with the help of the cooling fan, the excess heat will be "released" to achieve the effect of stabilizing the water temperature.
▎ Talk about science and turn on the correct way to warm up
Is it necessary to warm up the car in winter?
Need a hot car.
Whether it is a card friend in the south or a card friend in the north, pay attention to it, when your vehicle is parked for a long time, the oil in the engine will flow into the oil pan. Before and during the initial start-up of the engine, the moving parts of the engine are in a state of lack of oil and insufficient lubrication.
According to the statistics of a lubricant brand, more than 90% of engine wear is caused within 3 minutes after cold start. Therefore, it is still very necessary to warm up the car in winter.
How to heat up the car properly?
Start the machine and wait for the air pressure to come up, the oil pressure is stable, you can slow down without abnormality, and you can drive normally after the water temperature is normal.
I believe that most cardholders have the habit of heating up the car before starting in winter, but improper heating will also cause damage to their own car.
If the hot car is too long, it is easy to cause insufficient combustion, resulting in the formation of carbon deposits, and at the same time causing excessive emissions, which not only costs fuel, but also is easy to be troubled by the environmental protection road administration.
Therefore, Truck Home recommends that according to the ambient temperature, wait 30 seconds to 3 minutes after starting the engine, let the engine lubrication system establish sufficient oil pressure, and then the air pressure will also come up, and you can start driving.
But at this time, try to keep slow driving at low speed and low load, after driving 2-3 kilometers, the water temperature gradually rises, and the hot car process is completed, and you can drive normally.
Why is it sometimes difficult to start when the car is cold, and sometimes it takes several times to start successfully?
The most likely is a decrease in battery performance.
If the battery performance is not good, it is a headache for trucks with diesel engines.
1. The temperature is low, the oil fluidity is poor, and the engine running resistance is large.
2. The discharge capacity of the battery will also decrease when the temperature is low.
3. When the discharge performance of the battery decreases, the starter is weak.
4. If the diesel engine oil adopts the heating wire preheater, the preheating effect is not good due to the poor performance of the battery, which will also cause difficulties in starting.
All in all, in order to make the engine more efficient and get into working condition faster, the engineers are heartbroken. The large and small cycles of the cooling system are only one of the ways to improve the efficiency of the engine. There are many similar designs in the engine, and we will continue to educate you about them one by one in the future. Today's veteran driver advanced is here, if you still don't understand anything, or better hot car methods, suggestions, experience, etc., please leave a message in the comment area below.
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