Evaporative Emissions System: Operation
Fuel vapors are conveyed through the system to charcoal canister, where they are absorbed by activated charcoal. During engine operation the vapors are drawn from canister to carburetor and into engine.
The three-way valve is used to slightly pressurize the tank, provide an air inlet to the tank, preventing any possible vacuum. The valve also acts as a safety exhaust to prevent tank overpressure.
The two-way valve provides an air inlet to the fuel tank and acts as a safety valve to prevent tank overpressure. The one-way valves control the direction of fuel flow. The check valves are in the system to prevent fuel leakage in the event of an accident.