Catalytic converter, revisited

[cujet]

No, I've not installed a catalytic converter on my Listeroid. However, I am again considering the possibility.

VW jokes aside, smelling diesel exhaust all day while working in the yard, running off grid is simply nasty. My engine simply has mufflers attached to the exhaust ports. They stick out horizontally. This leads to exhaust fumes hovering at ground level and accumulating on my property. It also leads me to believe that the exhaust fumes are truly nasty. I hate diesel exhaust smell.

I'm considering mounting a set of high flow catalytic converters (one per cylinder) close to the head, in an attempt at reducing the pollution. My home typically does not draw all that much current, so the engine has long period of modest load. Even so, I believe there is enough heat to light off the cats.

Any thoughts? Any suggestions as to which one to purchase? Possibly VW will have a slew of less than effective exhaust treatment devices in the dumpster soon?

[mike90045]

Diesel's don't produce the type of gunk that a gasoline fuel cat can do anything with.   All the carbon dust will quickly gunk up the cat, and either plug it, or if it got hot enough somehow, start burning the carbon.

At least thats my thought on the subject.

[Thob]

In case you don't already know it - make sure you get a cat designed for diesel use - known as a diesel oxidation catalyst (DOC).  I think if I was to do this I would "Y" the two exhausts together into a single cat.

But my first thought would be to create a tall stack so the exhaust would exit high above ground level, along with one of those flap caps so it could exhaust straight up without letting rain in.  The higher temperature of the exhaust (compared to air temp) should carry most of the gunk up and away.  Plus a higher exit has a better chance of being mixed with the slightest of breeze.

Don't forget that in either case, you will have nasty stuff exitting the crankcase vent.  Which may actually smell worse than the exhaust.  You may find that you need to vent the crankcase into the intake manifold (PCV) - which carries it's own risks.

[Tom]

Or burn biodiesel, I like the smell of it. Although it will mess up that nice paint job.

[cujet]

I have a port on my intake manifold for a crankcase vent. So, I can run a PCV type system if I'd like.

There are Magnaflow brand "diesel" catalysts available on Ebay for 75 bucks each.

I could use a single, larger cat, with a properly fabricated Y manifold. However I was thinking the individual cats could be placed closer to the exhaust port for faster light off.

[EdDee]

Hi Chris,

I had a similar problem initially when I was setting up my toy... walls on 2 1/2 sides with exhaust coming out horizontally at waiste level... Smelt terrible and unless there was a real stiff breeze, the fumes hung around... I pushed the stack up to about 3 m and made the exit at 45 degrees upward towards the lesser walled area... solved most of the problems, noise too... In your case, I would think that joining the 2 pipes with a 2 into one manifold and through a single large upward pipe would allow best bang for buck effect... Cat could come later if you found it was still unpleasant... minimal changes etc at a later stage.. also, if things work OK on the single updraft, water heat exchanger would be an easy fit in place of or after the cat if u needed to later...

Just a thought...

Regds
Ed

[dieselgman]

Oh the smell of diesel in the morning! 

With all of the problems attendant to emissions controls on diesels, it would seem that a plain catalyst might not do any good. The "Regeneration cycle" for routine burnoff either involves an additional fuel injector at the filter, or excess fuel delivery in the engine during the exhaust stroke, or a DEF type reactor - mostly good for nitrous oxides. All requiring additional complications as well as quite high exhaust temps. I would certainly have my doubts.

+1 for a stack high and away from people.

dieselgman

[cujet]

Oh the smell of diesel in the morning! 

With all of the problems attendant to emissions controls on diesels, it would seem that a plain catalyst might not do any good. The "Regeneration cycle" for routine burnoff either involves an additional fuel injector at the filter, or excess fuel delivery in the engine during the exhaust stroke, or a DEF type reactor - mostly good for nitrous oxides. All requiring additional complications as well as quite high exhaust temps. I would certainly have my doubts.

+1 for a stack high and away from people.

dieselgman

Yes, a tall stack would be in order! But that's in the future when I have a shed for my Listeroid. Right now it's under a tent.

I was simply looking on Ebay at the first generation diesel cat's. The kind where no additional management was applied, as a first step in reducing haze and odor. I'm not at all sure it would work, as the low EGT's on the Listeroid may prevent light off. However, they are not expensive and it might be worth a try.

[LowGear]

Gorgeous system.

But I'm in the tall stack camp as well.  

Just the two exhaust pipes pointed upwards in a 6 inch stove pipe with an open bottom would solve your problems.  Thermopressure encouraged by the exhaust pressure would wisk all of your problems over to your neighbors.  Like those contraptions some use in lieu of a fan for their radiators.   And it would be light enough to lay down hide when not in use.

Casey

[BruceM]

How about a septic leach field type earth muffler to to clean it up a bit?

[Hugh Conway]

How about a septic leach field type earth muffler to to clean it up a bit?

That method does work.
I am using a similar "pit of doom" baffled underground muffler with a bout 12 feet of 4" plastic sewer pipe rising up behind my shop.
Cheap and easy to make......shovel and a few concrete blocks does it.
See this link http://www.navitron.org.uk/forum/index.php?PHPSESSID=ofaq86sbsefnaj6pskvbagr1e4&/topic,9775.0.html
None of the photos are of my set-up, but similar to the first construction.......As I recall, I may have copied it!

Not very portable though.
cheers,
Hugh

[dieselgman]

I know from experience that the in-ground silencer works great for noise... but what about the diesel fuel smell and such? That seems to be the issue for the catalyst providing an after-burn.

dieselgman

[vdubnut62]

My 97 Dodge came from the factory with a catalyst, it's a 12 valve mechanical pump engine. So yes under the correct circumstances it'll work without regen and DEF and the like.
My kick would be that a catalyst treated diesel exhaust simply smells awful, 'way worse than raw diesel exhaust. Burns my eyes and throat.  I have actually pulled off the road to wait for a diesel with catalyst to get way ahead of me. Put me down for a high stack too.
Ron.

[buickanddeere]

What the engine needs is to operate hard and hot enough to cleanly burn the fuel. Puttering at 20-30% load is going to burn too cool. Coolant temps of 210F would also be a benefit. Advancing the injection event  will increase combustion temperature . Unless the engine has been "blue printed". It could be operating with retarded timing at the moment . As previously stated a tall stack reduces noise and odor.

[LowGear]

BruceM,

You've tapped one of my buttons.  

How about a septic leach field type earth muffler to to clean it up a bit?

 
These systems are not leach fields unless they've been wrongly designed.  They are aerobic cleaning systems and I'd be reluctant to pump poisonous "stuff" down them.

Onward gentlemen.

FWIW:  buickanddeere post makes sense to me as well
.
Casey