Is it possible to refuel without turning off the engine?

[CharlotteDella]

It is possible to refuel without turning off the engine. Difficulty in dispersing the air-fuel mixture: During refueling, the concentration of the air-fuel mixture around the fuel tank increases correspondingly. Since the density of this mixture is greater than that of air, it is not easy to disperse. When the concentration of fuel vapor increases to a certain level, any spark generated by the running car engine may ignite and explode it. Gasoline foam is prone to spray out: When the car is not turned off, the fuel pump keeps working, generating a lot of foam inside the fuel tank. Under such circumstances, gasoline foam can easily spray out from the fuel tank, and the concentration of the air-fuel mixture outside the tank also increases. At this point, even a small spark may cause combustion or even an explosion.