The first thing we need to know is that gasoline is an electrolyte, which is flammable and volatile. The flash point of gasoline is only 50 degrees Celsius, that is, when the temperature reaches 50 degrees Celsius, gasoline will flash.
When refueling, the concentration of oil-gas mixture around the fuel tank will increase accordingly. Because the density of this mixed gas is higher than that of air, it is not easy to diffuse. When the concentration increases to a certain extent, any spark generated when the automobile engine is running may ignite it.
Therefore, when refueling, you should not only turn off the fire, but also make sure that you can't answer the phone, wear chemical fiber clothing (anti-static) and wear nail shoes (to avoid sparks caused by friction).
Danger causes of the additional oil not being closed:
1, the engine has been running at a high speed, without stalling, and the current on the car is also circulating normally. If it leaks electricity at this time, it will be very dangerous
2. When the engine is working, the exhaust port of the car will continuously discharge exhaust gas, often carrying Mars. If gasoline drips into the exhaust port at this time, it is very easy to catch fire.