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-   -   Charcoal Canister (http://www.hotrodders.com/forum/charcoal-canister-121688.html)

bentwings 08-07-2007 08:12 AM

Charcoal Canister
 
This is maybe a strange request. I want to install a charcoal canister on my fuel tank in my 41 Willys to prevent fuel vapor getting in the car.

These seem to be a dealer item as the local auto parts stores don't have them.

I can get one at the junk yard but I want a new one. I need one that is basic..IE simple two lines, one in and one out. I know they eventually hook to the air cleaner but I can get around that

The question is; What is a reasonable size and what car does it come on so I can get a new one. I prefer a GM.

ChevelleSS_LS6 08-08-2007 11:19 PM

the one on my 1996 Jeep Cherokee is pretty simple... one vac line in, one vac line out, not much to them, looks like a flat black coffee can, and they probably last forever as well? If it were me, I'd try a boneyard part for a mockup and see how well it fits and also how well the idea works, then get a new part if you want.

Don't forget to grab the bracket at the pull-n-pay, you could modify that to fit the 'mockup' before modifying new parts... I don't want you wasting money on new stuff to adapt and mess it up, it'd be better to mess up a used junkyard part if you see my logic...

bentwings 08-09-2007 12:55 AM

Hey thanks for the info. I'm going to go look for one maybe this week end. Good idea to try the junker stuff first.

ernkazern 08-09-2007 09:43 AM

charcoal canister
 
Look at the hoses on the ones in the junk yard carefully. If the hose to the intake runs to the air filter then you would have to have some way of closing off the air filter housing until the engine starts. Otherwise the vapors just end up in the atmosphere anyway. On the older systems you'd have the hose from the gas tank to the canister. The other hose would go to a manifold vacuum source, for example the PCV hose, so the vapors were sucked into the engine when it was running. There's a ported vacuum controlled valve in the manifold vacuum hose that doesn't allow manifold vacuum to the canister unless you're off idle.

ernkazern 08-11-2007 09:30 AM

charcoal canister
 
I've been looking through some old emissions hose schematics and I think the rubber hose(s) you see going to an air filter housing is/are from the AIR pump divertor valve. Either that or the temp sensors or vacuum bypass for the vacuum operated trap doors in the air cleaner snorkel. Neither are directly connected to the charcoal canister.

ChevelleSS_LS6 08-12-2007 11:54 PM

couldn't a one-way valve (pcv valve?) be used to keep vapors in the charcoal canister/lines? Just a thought.

ernkazern 08-13-2007 04:56 AM

charcoal canister
 
The problem there is that the PCV valve is connected to manifold vacuum which means eventually the vapors would leak out where the throttle plate is. That's never a tight seal. The other thing is that the systems are designed so the fuel vapors don't get drawn into the engine until you're cruising down the road. There are so many variables with the amount of vapors that you'd have problems maintaining a consistant idle speed and quality start up after start up.

bentwings 08-13-2007 06:38 AM

Do these really need to be purged? Since I'm planning to use this on the vent line of the tank, air will come in thru the canister as well as trap fumes while the car is not running. This line will just have a air cleaner of its own attached to it....lawn mower type. The other line will go to the tank. Maybe I should use 2 vents on the tank. One would be used as described, the other would be a one way such as a check valve on a power brake unit. The check valve line would provide extra flow during high fuel useage..ie full throttle. Under normal cruise the air coming into the tank would come in thru the canister. If it needs a little more, the air can come in thru the check valve. All venting going out of the tank however will go thru the canister. The check valve could also be an inverted tip over valve,..ball bearing type.

This isn't an emmission application except to prevent fumes from entering the car.

ernkazern 08-13-2007 10:14 AM

Charcoal Canister
 
The reason the canister has to be purged is that after a while it will fill with vapors and will smell of gas. It's not a big deal to install one, you just buy a canister and a canister control valve and hook it all up. I'm having a difficult time picturing the rest of your set up and how it would work properly. There is a filter on the bottom of the charcoal canisters I'm familiar with. I'm not sure what you mean by running to it's own air filter. What happens is that when the purge valve opens fresh air is drawn into the canister through the bottom through the filter. That air mixes with the fuel vapors as they go into the engine. A check valve in the vapor vent line prevents pulling a vacuum in the fuel tank. The only problem I see is that the system I'm describing is an older GM one and you may not be able to get parts for it anymore. The newer ones are controlled by electric solinoids activated by the ECM. In any case I'm no instructor and sometimes don't explain things very well. I think the first thing you have to do is have a complete understanding about how the systems work then I'm sure you can design one easily enough.

bentwings 08-13-2007 10:49 AM

Hey thanks for the info. I'm going to do a layout of the system and make a Solidworks drawing. I can maybe post it so that it will be more clear.

I've seen this type of system so it is not my idea but I did not really paid attention to the details. Not enough disc space in my head. haha Sometimes streetrod stuff is not exactly correct but it works well enough for the limited amount of use we give them.

My thinking is that air will be continuously drawn in through the canister as fuel is used. When the car is shut off and simply waits for me to bring it to life again, the canister gathers fumes as required. Once the motor is started and begins to use fuel, air again comes into the canister, purging it.....hopefully.

I would think any dumping of vapors into the carb air cleaner could cause idle problems. A ported vacuum might work. My system will eventually have a blower and possibly an EFI injector so A/F ratio will be monitored. I would guess that fuel vapors dumped in will be accounted for by the o2 sensors. But I surely don't need random fuel vapors dumped in at idle, it's hard enough to keep a blown motor clean at idle. Consider also that this mess will be run on E-85. ($2.05/ gal today) I can probably tolerate some varance in mixture just as an alcohol motor can.

You know it is funny..in my younger days I would just roll the window down (hand crank not power) and say "gas fumes are just part of hot rodding, like noise, live with it." Today after 55+ years of sniffing gas and all the other hotrod fumes, I really long for a little cleaner air. haha Now if it was diesel fumes, it would be a different story. haha....yeah right a Willys with "stacks" ...I really don't wish to be banned from hotroding. haha

I'm going to the junk yard....back later.

KULTULZ 08-13-2007 12:56 PM

http://smilies.storagebin.us/smilies/confused.gif

I have been watching this thread for a few days and the confusion it is causing me makes me want to ask;

You have a fuel system that is running so rich that fumes are drawn into the passenger compartment? If so, an EVAP (or similiar) system is not going to help much. EVAP is designed to contain fuel vapors while the car is off and then burns the excess fumes while running.

Is the engine carbureted or injected? For a EVAP to work anywheres efficiently, you will need at the least closed air cleaner(s). EVAP also vents the fuel tank and carburetor bowls.

-EVAP OVERVIEW-

It sounds to me that either the fuel mixture needs to be leaned out or the passenger compartment needs to be sealed more tightly (exhaust pipes run to rear bumper?). Is this a steel car or fiberglass?

Now all of this having being said, early cannisters (metal) used a replacement filter and later cannisters are plastic throw away.

bentwings 08-13-2007 02:44 PM

Sorry for the confusion. It's not the exhaust fumes. It's gas fumes from the fuel tank mounted in the trunk area. Even though the trunk area is sealed off, when filling the tank some fumes remain in the trunk. Eventually there will be an external filler. The trunk is well vented. There is an external vent ( outside of the trunk) on the tank too, but if the car just sits on a hot day the fumes will get into the car, this is what I'm really after.

The exhaust is out the rear past the body lip and does not leak.

The focus of the exercise is to vent the tank so fumes don't get into the car by the venting. There is an external vent but by capturing this I hope to clean up the car.

ernkazern 08-13-2007 03:35 PM

Charcoal Canister
 
You're on the right track venting the vapors to a charcoal canister. Is there already some sort of a vent in the tank, or does the system you have now rely on a vented gas cap to relieve pressure in the tank?

bentwings 08-13-2007 09:11 PM

1 Attachment(s)
I have an AN-8 male vent fitting and a screw on cap with no vent (Chassis shop 2"). Also I have a AN-8 male return that is capped.

here is the cad jpeg. It's about 16 gallons. 20 x 15 x 14.5. 14 ga 5052-0 aluminum.

KULTULZ 08-14-2007 01:26 AM

Quote:

Originally Posted by bentwings

It's not the exhaust fumes. It's gas fumes from the fuel tank mounted in the trunk area. Even though the trunk area is sealed off, when filling the tank some fumes remain in the trunk. Eventually there will be an external filler. The trunk is well vented. There is an external vent ( outside of the trunk) on the tank too, but if the car just sits on a hot day the fumes will get into the car, this is what I'm really after.

The focus of the exercise is to vent the tank so fumes don't get into the car by the venting. There is an external vent but by capturing this I hope to clean up the car.

How does the manufacturer of the fuel cell suggest venting? There is usually a vent associated with the filler pipe.

You don't smoke do you? :eek:


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