What Causes Gas to Escape When Opening the Fuel Tank Cap?

[LaMason]

It is normal for gas to escape when opening the fuel tank cap. Gasoline is a volatile liquid, and there is always some gasoline vapor inside the fuel tank. Here is some relevant information: 1. Since gasoline is a volatile liquid, designing the fuel tank to be completely sealed is unsafe. However, directly releasing gasoline vapor from the tank into the atmosphere would cause environmental pollution. 2. The carbon canister system is specifically designed to absorb gasoline vapor from the fuel tank. When the engine is not running, the carbon canister can absorb the gasoline vapor inside the tank. Once the engine starts, the carbon canister solenoid valve opens, allowing the absorbed gasoline vapor to enter the combustion chamber through the intake manifold and participate in combustion. This method prevents fuel waste and environmental pollution.