Purging Charcoal Canister by Return Fuel Line

[buffydores]

Hey Folks: Here's a question. I'm running a Ramjet 350 that's not setup for evap provision stuff (as far as I know). I'd like to hook a charcoal canister up to my vent lines coming from my fuel tank to address gas fumes in the garage, but I don't think I want to simply hook the purge line up the air intake or something.

Here is my stab at an ideal. Could I "T" the purge line into the return fuel line with a one way valve that opens at like 5 psi? If there's enough velocity on the return fuel, it should create a pressure differential to suck on it. I'm guessing something like 15in/s or 20in/s speed would create 5+psi.

Tell me why this doesn't work, because I'm not seeing this idea out there.

I assume the purge line acts like a bypass of the charcoal elements, so there would be constant vapors flowing through, but not necessarily going through the charcoal.

[buffydores]

I think I'm already seeing the problem. From all the diagrams out there, it looks like the purge is not a bypass for the vapors. The vapors still appear to go through the charcoal. I'm just not sure why.

[Bigdav160]

There should not be any liquid in the evap system. Fuel vapors from gasoline storage (carb and fuel tank mostly) get stored in the charcoal. The purge line is just a connection to engine vacuum (ported) that pull the vapors from the canister (purge) and burns them. No ported vacuum on your throttle body?

[buffydores]

Probably, but how would you control the purge?

[Bigdav160]

When the engine is running and the throttle is open it will be purging. That's how GM did it on the TBI trucks until '95. In '95 they added a computer controlled solenoid.

[buffydores]

Anybody know if the Ramjet uses a solenoid or is simply hooked to the throttle body. I'd look, but I'm having the transmission rebuilt.

[68c10airstream]

bigdav160 is correct, the vapors are purged out of the canister by pulling air through a filter at the base of the canister on some or a open small port on the top. This has a drying affect so the charcoal can continue to accept more vapors in the future.

[buffydores]

So what happens if I just hook up the vent line and leave the purge and air inlet lines open to ambient. Will you capture fuel vapors in the garage and release them to atmosphere as you drive down the road due to the pressure drop due to the velocity of the vehicle?