How Does a Vehicle Charcoal Canister Purge Solenoid Valve Work?

[JuniperRose]

The working principle of a vehicle's charcoal canister purge solenoid valve involves controlling the purging effect of the charcoal canister through the modulation of electrical pulse width. The ECU (Engine Control Unit) adjusts the grounding circuit of the solenoid valve to connect or disconnect at a specific frequency based on different engine operating conditions. By manipulating a normally closed solenoid valve, the ECU controls the vacuum that purges the charcoal canister. When the engine is turned off, the sealed fuel tank creates a negative pressure inside due to fuel consumption. Under this negative pressure, gasoline vaporizes more easily than under normal atmospheric pressure, eventually balancing with the atmospheric pressure. The activated charcoal canister storage device plays a crucial role in this process.