Author Topic: Activated charcoal as an exhaust filter ?  (Read 11629 times)

jens

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Activated charcoal as an exhaust filter ?
« on: September 13, 2008, 04:35:01 AM »
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« Last Edit: December 26, 2009, 09:37:48 AM by jens »

mobile_bob

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Re: Activated charcoal as an exhaust filter ?
« Reply #1 on: September 13, 2008, 05:38:56 AM »
Jens
i don't know of anyone that has successfully got it to work, seems i read somewhere the activated charcoal rapidly plugs its pores
with particulate and starts to restrict to the point of be non effective.

i think this was an early attempt to meet tier whatever by the major's, that didn't show promise

but it might in a listeroid, if you have enough of it and are up to frequent changes?

i think one might be better off burying the exhaust and planting vegetation over it, let the plants and microbes deal with the exhaust components.

bob g
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cujet

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Re: Activated charcoal as an exhaust filter ?
« Reply #2 on: September 14, 2008, 02:07:19 AM »
Each granule of carbon contains microscopic pores that absorb contaminates. Coconut shell carbon is among the best, by the way. Those microscopic pores would clog in a nanosecond with Listeroid exhaust. Even though the bed of carbon is not clogged.

I suggest a catalytic converter for diesel engines. It will change the exhaust smell to something much more pleasant. Plus, a up side is that it will convert CO, and HC to CO2, which we all know is great for global temperatures:) Seriously, it will help.

Chris
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oliver90owner

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Re: Activated charcoal as an exhaust filter ?
« Reply #3 on: September 14, 2008, 09:10:29 AM »
I suggest a catalytic converter for diesel engines

As long as you plumb it on the hot side of any heat recovery or loss from thesystem.  they are not good if too cold :)

Raegards, RAB

cujet

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Re: Activated charcoal as an exhaust filter ?
« Reply #4 on: September 15, 2008, 05:36:40 PM »
Yes it is true, the cat will likely take a while to light off, even if positioned quite close to the exhaust port. However, once lit, it will remain so. My diesel Jetta has a cat downstream of the turbo and it lights off nearly right away and exhaust smells clean quickly. There is no funny business causing the cat to light off, such as a rich mix or late injection. It simply works. A listeroid under load produces enough exhaust heat.
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M61hops

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Re: Activated charcoal as an exhaust filter ?
« Reply #5 on: September 15, 2008, 10:29:03 PM »
Does anybody think that a used cat from a gasoline pasanger car would work if mounted to the exaust port of a 6/1?  I'd like to scrounge a low milage cat and try this as heat is the main thing I'm trying to harvest from my genset.  I wonder what the effect of burning WMO or WVO would be on a catalytic converter?  I'd guess if that if the converter was lit when you switched to the heavier fuel that the cat would digest the exaust OK?  I wonder if the cat would clog up if you hit it with exaust of WMO or WVO before it was up to temp or if the cat would light off and clean itself up OK?  Does anybody know if this is a workable thing for a 6/1?  It seems like a good idea to me but it will take me a while to scrounge up a good cat as it is aginst the law in California for junkyards to sell used catalytic converters.  Unless I hear that this won't work from someone who has tried it I'll ad this to my list of things to try and I'll report my results to the group.  ;)               Leland
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SteveU.

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Re: Activated charcoal as an exhaust filter ?
« Reply #6 on: September 16, 2008, 12:07:56 AM »
Oh boy. When will I ever learn to keep my mouth shut.
Too many questions on this thread to address with any accuracy. I'll try. Lord knows I'll try.

NO a cat off of a gasoline automobile will not work.
1) It will be too big to heat up and light off and then stay hot enough to do anything.
2) They are designed with a heat absorbing reduction section first to strip the Ox molocules off the NOx and then use the now freed up O2 (with sometimes additional air injection) to oxidize convert(heat producing) the HC's and CO to CO2 and H2O. The active catalysts are wrong for diesel cumbustion gases. The soot will coat and deactivate them. Just like the lead that use to a gasoline additive.

No a cat out of a wood stove will not work.
Again requires too high a volume of gas flow to heat up to the minimun 800-1200 degree F. to become active. Although it May have useable catalytic coatings and a physical stucture able to handle the soot. But then what about the sulfer? That's why they are refining it out you know. Coat deactivates the catalytic elements just like the lead did.

A small automotive diesel cat??? I don't think so, but I don't know. A 1.8L Lister/iod at 650-1000RPM probably pumps less than 1/4 the gases volumn out the exhaust as a 1.8L 2200-2800RPM auto diesel engine. Idle speed cat cooling off is an Emissions Techs big buggaboo.
Mount the smallest diesel cat on the exhaust flange. Insulate it to keep it hot. Adjust your injection timing and close the exhaust valve later to get the exhaust temperature up and so to have enough fuel and oxegen left for catalyst oxidization. . . well maybe, just maybe.
Or add a turbo like Cujet has to push extra O2 through the engine out the cat. . .or add a belt driven air pump (Air Injection Reaction) like some of the vehicles used to have. Yoiu WILL need more O2 to the cat for it to light off and get hot enough to function.

Hey Jens, I thought Vegioil exhaust was suppose to smell good. . .  like fries/chips cooking?

All my own opinions,
SteveU.  
 
« Last Edit: September 16, 2008, 02:27:12 AM by SteveU. »
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M61hops

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Re: Activated charcoal as an exhaust filter ?
« Reply #7 on: September 16, 2008, 05:39:58 AM »
Yes Jens, the used cat law seems stupid and I forget the excuse that was used when it was instituted.  Thanks for the info SteveU!  This might not be a workable idea, I'll have to read up on catalytic converters for diesels to aquaint myself with the issiues.  :P      Leland
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mobile_bob

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Re: Activated charcoal as an exhaust filter ?
« Reply #8 on: September 16, 2008, 06:21:16 AM »
at have given some thought to the use of a cat on a changfa, not to clean the exhaust but to improve the heat coming off the exhaust.
with some research i found a canadian manfacture that makes small units for small displacment diesels some time ago, and would have to dig
in my notes to find them again.
they were on the expensive side iirc something around 3-400bucks, (probably why i don't have their details at my fingertips)

after then i found a seller on ebay that sells new cats , again small but made for gas engines and they used to be quite reasonably priced
at around 40bucks for a weld up unit, but i checked again recently and their is a 80 plus dollar core charge because of the platinum content
which they recover for resale i guess.

i agree with steveu, in that i would have to put a smog pump on the engine as well to get added air and also the engine would have to burn
desulferized fuel, and run at near peak loading i suspect to keep enough heat up to support lighting it up.

when the cats were 40 bucks i thought it might be worth some testing, but not sure i would want to go upwards of 150bucks plus other bits w/labor
to try and get increased exhaust heat.

although some day i might give it a try.

then there is this,
the typical ceramic cats don't hold up well with a diesel engine, evidenty according to the canadian manufacture the diesel vibration will break up the
ceramic core and the diesel units use something other than ceramic to hande this vibration.

anybody get one to work on their engine reliably and reasonably priced i know i wanna hear about it :)

bob g
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rpg52

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Re: Activated charcoal as an exhaust filter ?
« Reply #9 on: September 16, 2008, 05:14:15 PM »


". . . it is against the law in California for junkyards to sell used catalytic converters"  I may be wrong, but I think the rational is to prevent (or reduce) the theft of catalytic converters from off of cars parked on the street.  It is still occurring anyway, but by limiting the resale, it theoretically reduces the incentive to steal them.   :( 
Also, the cats in Calif. are different than in other states - not sure how they are different (more platinum?, no idea), but if you buy one to replace the one for your car, it has to meet different standards to pass the smog tests.
Ray
PS Listeroid 6/1, 5 kW ST, Detroit Diesel 3-71, Belsaw sawmill, 12 kW ST head, '71 GMC 3/4 T, '79 GMC 1T, '59 IH T-340

cujet

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Re: Activated charcoal as an exhaust filter ?
« Reply #10 on: September 18, 2008, 09:19:42 PM »
Don't forget that on a single cylinder exhaust, it is easy to add additional air with a reed valve. Air will enter during the low pressure time of the cycle. No pump needed.

Chris
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SHIPCHIEF

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Re: Activated charcoal as an exhaust filter ? How 'bout something different?
« Reply #11 on: September 19, 2008, 03:46:58 AM »
I once took a tour of the Northern-Lights factory in Ballard WA where they make generator sets for boats etc.
They were just marketing a catalytic converter for diesel engines, and they gave me the sales pitch and a brochure.
Basically, the exhaust temp is too low to start the reaction, so a 2Kw electric heater is required to start and thermostaically maintain the temp.
That doesn't work well for us, and I just checked their site, it looks like they don't offer it now. Instead they offer an exhaust water filtration system for the cooling/exhaust water discharge.
I wonder if an Electrostatic Precipitator would work? My Mom's home heating furnace has two elements that get washed in the dish washer once a year. They trap household dust, and do a good job of it.
Scott E
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cujet

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Re: Activated charcoal as an exhaust filter ?
« Reply #12 on: September 19, 2008, 03:36:13 PM »
Hey Scott,

I am glad you brought that up. My 06 Jetta has a heated O2 sensor just upstream of the cat. It must "light off" the cat. Because my car exhaust smells ultra clean almost right away. I had not considered that the O2 sensor was lighting it off. Last year at 40,000 miles, the O2 sensor heater failed (under warr). I noticed that the car smelled just as clean. But I did not notice if it was as clean right after startup.

I can't imagine that the 2000W heater is needed for long. Also, the way some of us run our listers (very hard) I would expect an auto light off with the right setup. Once lit, I would expect catalytic function would continue until engine shutdown.

By the way, the lister is oxygen rich under low loads. So, no additional ari would be required at moderate loads.

I am interested in trying this

Chris
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Tom

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Re: Activated charcoal as an exhaust filter ?
« Reply #13 on: September 19, 2008, 05:51:37 PM »
Just running a 2 kw heater with a 6/1 would bring up the exhaust temp pretty quick, even without the heater being in the exhaust. I've worked around a duramax diesel while it was working hard and the smell was similar to a propane fueled engine.
Tom
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SteveU.

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Re: Activated charcoal as an exhaust filter ?
« Reply #14 on: September 19, 2008, 09:42:11 PM »
Hey this cat talk is starting to get interesting.

Cujet I DID forget about exhaust asperation (gulp) valves. They worked great on up through 4 clylinder engines. Good idea. Can be found on some carburated Chrysler and Honda cars.

Any one trying a cat should try and use the smallest pellet /pebble bed GM style you can source. The loose round beads will not break up with viberation and MAY even rub them selves clean of soot.

Yes the big manufacturers VW, MB, FORD, and IZUZU/GM are making various cat exhaust systems work sucsessfully now. But realize: only with ultra low sulpher fuel, on engines with at least four times the exhaust gas flow rate as any CS Lister, and with high speed/ultra high pressure fully electronically controlled fuel injection systems.
They are controlling and changing the injectors timing and duration to acheive what they determind their cat needs for oxegen, fuel and temperature inputs in the exhaust stream.
The upsteam and down stream oxegen sensors are information feedback sensors to the computor to tell it how good of job its doing and to monitor catalytic efficiency. They are heated with only a couple hundred watts to come up quickly and maintain their minimum operating temperature of 500-800 degrees F.  Look at the small heater wire size. Any 12volt electrical circut capable of 2000watts in going to at least #8,#4, or even #2 guage wire size.
So no; commonly the cat has to get hot enough th light it self off.

Diesel designed O2 exhaust sensors along with exhaust and cat temperature sensors would be ideal for monitoring your engine need for modification to fuel, timings and any needed extra exhaust air injection.
Sounds like VW would be the source for some soot resitient sensors.

All my own opinions
SteveU.
Use it up. Wear it out. Make Do, or Do Without.
 Electrodyne 12vdc. AC MeccAlte 8.5kw
John Deere 950 w/Yammar 3cyl IDI; Peterson 21" sawmill w/20hp Kohler v-twin; four Stilh chainsaws,  Stilh weedeaters; various Kohler, Onan, Honda, Briggs, Tecumseh singles.