What is the function of automobile carbon canister?

The carbon canister is actually a part of the gasoline evaporation control system (EVAP), which is introduced to prevent fuel vapor from escaping into the atmosphere after the engine stops running. After the engine is turned off, gasoline vapor and fresh air are mixed in the fuel tank and stored in the activated carbon fuel tank. When the engine is started, the solenoid valve installed between the activated carbon canister and the intake manifold is opened, and the gasoline vapor in the activated carbon canister is brought into the cylinder by clean air to participate in combustion under the vacuum degree of the intake pipe. This not only reduces emissions, but also reduces fuel consumption.

1. Carbon canister is a part of gasoline evaporation control system (EVAP), which is usually installed between the fuel tank and the engine. The system is introduced to prevent fuel vapor from escaping into the atmosphere after the engine stops running. Because gasoline is a volatile liquid, the fuel tank is often filled with steam at room temperature. The function of fuel evaporative emission control system is to introduce steam into combustion and prevent it from evaporating into the atmosphere. The storage device of activated carbon tank plays an important role in this process.

2. Working principle

Because of the adsorption function of activated carbon, when the car is running or turning off, gasoline vapor in the fuel tank enters the upper part of the activated carbon tank through the pipeline, and fresh air enters the activated carbon tank from the lower part. After the engine is turned off, gasoline vapor and fresh air are mixed in the fuel tank and stored in the activated carbon fuel tank. When the engine is started, the electromagnetic valve of the fuel evaporation purification device installed between the activated carbon canister and the intake manifold is opened, and the gasoline vapor in the activated carbon canister is sucked into the intake manifold to participate in combustion.

Gasoline is a volatile fuel, and the fuel in the fuel tank volatilizes quickly, which will increase the pressure in the fuel tank. When the pressure reaches a certain value, it will cause certain danger, so people try to balance the pressure. At first, the tank cover was made into a pressure limiting valve. When the pressure is higher than a certain value, the pressure limiting valve is opened and the gasoline vapor is sent to the atmosphere. Later, from the perspective of saving fuel and protecting the environment, people set up a carbon canister, which was filled with activated carbon with high water absorption. Activated carbon absorbs fuel vapor. When the car starts, the solenoid valve of the activated carbon tank is opened in time to pour the absorbed fuel vapor back into the intake manifold, which is fuel-efficient and environmentally friendly.