A Body GM Car Evap System 76 El Camino
Introduction
The Evaporative Emission Control (EVAP) system is designed to prevent fuel vapors from escaping into the atmosphere. The system consists of a number of components, including a fuel tank, a fuel cap, a purge valve, a charcoal canister, and a vent valve.
Fuel Tank
The fuel tank is the primary storage container for the vehicle’s fuel. The tank is sealed to prevent fuel vapors from escaping.
Fuel Cap
The fuel cap is designed to seal the fuel tank and prevent fuel vapors from escaping. The cap is typically made of plastic or metal and has a rubber gasket to create a seal.
Purge Valve
The purge valve is a solenoid-operated valve that controls the flow of fuel vapors from the fuel tank to the charcoal canister. The valve is normally closed, but it opens when the engine is running to allow fuel vapors to be purged from the tank.
Charcoal Canister
The charcoal canister is a cylindrical container filled with activated carbon. The activated carbon adsorbs fuel vapors, preventing them from escaping into the atmosphere.
Vent Valve
The vent valve is a solenoid-operated valve that controls the flow of air into the charcoal canister. The valve is normally open, but it closes when the engine is running to prevent air from entering the canister and desorbing the fuel vapors.
Operation
The EVAP system operates as follows:
1. When the engine is off, the fuel tank is sealed and the purge valve is closed. Fuel vapors are trapped in the tank and the charcoal canister.
2. When the engine is started, the purge valve opens and allows fuel vapors to flow from the fuel tank to the charcoal canister.
3. The activated carbon in the canister adsorbs the fuel vapors.
4. When the engine is running, the vent valve closes and prevents air from entering the canister. This keeps the fuel vapors adsorbed on the activated carbon.
5. When the engine is turned off, the purge valve closes and the vent valve opens. This allows air to enter the canister and desorb the fuel vapors.
6. The desorbed fuel vapors are then drawn into the engine and burned.
Troubleshooting
If the EVAP system is not functioning properly, it can cause a number of problems, including:
* Increased fuel consumption
* Poor engine performance
* Emissions failures
If you suspect that the EVAP system is not functioning properly, you should have it inspected by a qualified mechanic.
Conclusion
The EVAP system is an important part of the vehicle’s emissions control system. It helps to prevent fuel vapors from escaping into the atmosphere and contributing to air pollution. If the EVAP system is not functioning properly, it can cause a number of problems, so it is important to have it inspected and repaired if necessary.
