Author Topic: Catalytic converter to reduce exhaust odor  (Read 1079 times)

cujet

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Catalytic converter to reduce exhaust odor
« on: February 27, 2020, 02:29:20 PM »
I have 2 Listeroids, a 6/1 that's cranked up to a 7.5/1 by raising the RPM and a 20/2 that's slowed down a bit. Both engines have automotive mufflers and are quiet enough for my location. However, I absolutely despise the smell of diesel exhaust and while both engines have clear exhaust when operating, they do have enough odor to be bothersome.

Years ago, I remember some effort was being made to develop an emissions compliant Listeroid. That's not my goal here.

What I've been thinking about is purchasing a diesel specific catalytic converter and mounting it as close to the head as possible. I have TIG welding equipment and it would be quite easy to weld a flange that installs it directly on the head. Yes, I know most diesel owners desire to "delete" the emissions equipment. However, I have sufficient power, and I'm sure any HP loss would be minimal with a low restriction catalyst.

What I'm not sure about is whether it would help, and whether or not it would actually "light off" and function.

Has anyone done such a thing?
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veggie

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Re: Catalytic converter to reduce exhaust odor
« Reply #1 on: February 27, 2020, 09:39:13 PM »

cujet,   long time !  :)

To my knowledge a Cat Converter only works on gasoline emissions.
Diesels must use a Diesel Particulate Filter (DPF) which also reduces odour considerably.
New diesels have a fuel re-burn system which introduces fuel into the hot exhaust stream just downstream from the engine to create additional combustion in the DPF. This helps to burn the particulates and partially clean the DPF. Eventually they do clog.
In the case of my diesel the "regen" burn cycle lasts approx 10 minutes every 7 hours of driving.

I heard somewhere that in Europe they have a fuel additive which changes the diesel exhaust odour to something less offensive.
I have not researched to see if anyone here carries it in North America.

cheers,
veggie
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AdeV

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Re: Catalytic converter to reduce exhaust odor
« Reply #2 on: February 27, 2020, 09:53:46 PM »

I heard somewhere that in Europe they have a fuel additive which changes the diesel exhaust odour to something less offensive.
I have not researched to see if anyone here carries it in North America.


Sort of - it's not a fuel additive, it's an exhaust catalyzer, called AdBlue. It's purpose is to reduce NOx emissions to something sensible. I couldn't tell you if it affects the exhaust smell at all, it's currently mainly used in large commercial vehicles, although some passenger vehicles now run it as well.

Adblue is a urea based chemical. I'm not sure exactly how it's applied, except it's a liquid that's injected into the exhaust stream somewhere. Some googling might come up with enough info to allow you to experiment & see if it does reduce the odour at all. I suspect your only other option would be to filter it to an insane degree.

An EGR (Exhaust Gas Recirculation) system might help too - it's just a small pipe joining the exhaust to the inlet, and allows some of the exhaust gas back in with a fresh intake charge. Most diesel cars have an EGR valve somewhere which inevitably - and expensively - goes wrong. I'm not sure what it's purpose is, maybe they don't run well on exhaust gas when cold or something?
Cheers!
Ade.
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saba

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Re: Catalytic converter to reduce exhaust odor
« Reply #3 on: February 28, 2020, 01:43:39 AM »
Its like adev says, it's urea (cow piss} just started working with it so it's still sort of new to me. Big cat 3516 I think ? then up in the exhaust there is a nozzle which blows in the urea with air, behind that there is something that looks like a catalizer box. units with honeybee grid from keramics, further up the funnel we have the soot filter with a burner stove underneath. Every 4 hours or so it's burning the filters clean. doesn't look like something  that would work on a lister.

I just moved here so not so much hands on experience yet. Didn't go up the funnel to check for the smell but I can tell you it's really clean what comes out. Under full load there is no sign of exhaust

For smell try vegetable oil
Or add natural gas or propane to your intake, you can run it 90% gas just use the diesel to ignite.

Bernhard

 

glort

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Re: Catalytic converter to reduce exhaust odor
« Reply #4 on: February 28, 2020, 05:50:08 AM »

Diesel and Petrol "cats" work Differently.

Petrol cats get hot from the exhaust temp itself  and burn pretty quick and are more of a constant operation.  Diesel cats Catch the particles and then use extra fuel injected into the exhaust to heat them up and burn off.

There is no way a petrol cat is going to work with a diesel and especially something like a Lister.  No where near enough heat to get the catalyst glowing to burn anything off. They also have an operating range. too cold they don't work, Too hot they melt down.

If the smell is worrying you ( love the smell of Diesel in the morning...)  Why not just extend the exhaust so it is directed out your shed or High up so it is away from your olfactory senses? Bit of pipe will be the cheapest, simplest and most simple solution of all I think.

You could also run Veg oil as suggested but you will have to run at least 50% to hide the diesel smell.
I have tried many other oils and most of them you can't smell at all even when run at 100%.  Mate and I tried Coconut oil many years back when we got on to a load of the food grade stuff that had gone out of date. We were quite excited about it because the stuff smelled unreal and we thought would would be filling the neighborhood with the sweet aroma.

Nothing. Not so much as a whiff did it produce when burned.  Dissapointed we made Bio diesel with it and not a hint with that either.
Duck fat was the same. Lard/ tallow is a bit stronger smell when burned but summer fuel only as it sets solid below about 30o C.
 Given that's a cool summers day here, I used to save up a fair bit of it for summer use and it was really good.

I don't know if Adblue would do much for the aroma.  It's mainly to reduce Oxides of Nitrogen I believe.  Mate had a truck that was euro 2 emissions compliant years ago that ran it.  He bought industrial Urea and would dissolve it in a drum of water. The water would  initially freeze the condensation on the outside and remain cold enough to have heavy condensation for a week.

As I remember there was still a feint diesel smell. Those things run so relatively lean and have so many emissions controls it's hard to say if the adblue made any difference to the smell but I would guess not.

EGR I don't believe would do much either. That is to introduce inert gas into the combustion chamber to cool it to prevent oxides of nitrogen again which are formed at high combustion temps and are a big concern with emissions. They use that on diesels as EGR isn't particularly successful as it clags the intakes as VW and toyota engines have suffered from badly in the past.

I believe your best bets are to run Veg oil or bio Diesel, Extend the exhaust pip or get a fan and have it blowing the exhaust gas away from you.  :0)


cujet

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Re: Catalytic converter to reduce exhaust odor
« Reply #5 on: February 28, 2020, 11:20:13 PM »
Thanks all. I work in the aviation industry, so I have quite a supply of Jet-A. Currently about 500 gallons.
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AdeV

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Re: Catalytic converter to reduce exhaust odor
« Reply #6 on: February 28, 2020, 11:27:57 PM »
Thanks all. I work in the aviation industry, so I have quite a supply of Jet-A. Currently about 500 gallons.

Jet-A is basically fancy Kerosene isn't it? All I'd say is - does it have enough lubricity (unlike Kero) to prevent your fuel pump from seizing? Also - from what I recall of flying - burning Jet-A smells a lot like a diesel...
Cheers!
Ade.
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cujet

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Re: Catalytic converter to reduce exhaust odor
« Reply #7 on: February 28, 2020, 11:43:56 PM »
I am going to give it a try. There are diesel specific catalysts that light off at 200 deg C. It should work. Maybe I can find one from a VW.
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mike90045

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Re: Catalytic converter to reduce exhaust odor
« Reply #8 on: February 29, 2020, 01:12:50 AM »
My 6/1 under load, gets the exhaust pipe all the way up to about 330F ( 165C ) and I suppose the gas is a little bit hotter than that, but I don't have much hope that it will fire off a 200C cat.  But try it if you got the parts

glort

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Re: Catalytic converter to reduce exhaust odor
« Reply #9 on: February 29, 2020, 11:27:54 AM »

All I'd say is - does it have enough lubricity (unlike Kero) to prevent your fuel pump from seizing?

IP may not seize ( or it might) but it WILL wear excessively. Won't do the injector a lot of good either.

I would be adding a generous amount of 2 Stroke, Biodiesel or Veg oil to the jet A. A good mate of mine works on Navy choppers and gets all the ( rare marinised ) turbine fuel he wants.  He mixes it with about 25% used veg oil and has tuned his engine in his Isuzu truck to it and the thing goes like a stung cat. Been in the thing a few times and it is literally scary fast and unbelievable for a stock Diesel 3L.

Forget about commercial lube additives. I saw a test done some time back and they were all but useless except for making profits for the companies producing them.

2 stroke at 50:1  or veg oil or bio at whatever you like will add a great deal of lubricity to diesel, kero or Turps as I have run as well.... which also smelled like diesel when Burned.

cujet

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Re: Catalytic converter to reduce exhaust odor
« Reply #10 on: March 01, 2020, 01:30:13 PM »
  - [Jet-A] does it have enough lubricity to prevent your fuel pump from seizing? Also burning Jet-A smells a lot like a diesel...

In a past life, my late friend (Rocketboy, Bob Gross) , along with Horsepoor, and I brought home 5500 gallons of Jet-A (along with other fuels and oils) . We purchased diesel vehicles/motorhomes and so on, then ran them on Jet-A only after HFRR (high frequency reciprocating rig) testing the fuel for lubricity. I think I've posted about this in the past. By memory:

Jet-A had an HFRR wear scar of 650 or so,
Adding Stanadyne lubricity additive brought the numbers down some,
A combo of Stanadyne and 200 to 1 TCW-3 two stroke oil lowered the numbers to 255. Well below the 450 requirement for diesel.
Note: lower is better

I also have an Alfa Laval centrifugal filter that cleans the fuel of any moisture and particulates. Fuel comes out crystal clear.

So, on every batch of Jet-A, we add some TCW-3 and Stanadyne lubricity additive. None of us have experienced any problems with the fuel.



Burning Jet-A in a diesel engine smells exactly like burning diesel fuel. A characteristic stench that I find objectionable.
« Last Edit: March 04, 2020, 02:40:11 PM by cujet »
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cujet

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Re: Catalytic converter to reduce exhaust odor
« Reply #11 on: March 01, 2020, 01:37:07 PM »
My 6/1 under load, gets the exhaust pipe all the way up to about 330F ( 165C ) and I suppose the gas is a little bit hotter than that, but I don't have much hope that it will fire off a 200C cat.  But try it if you got the parts

That seems to be on the low side. I recall seeing 450 F with a non contact thermometer. Remember, you must paint the pipe black to get a really accurate reading.

Even so, you may very well be right, the lister exhaust may not have enough temperature to light off a Diesel catalyst when running at lower loads.
« Last Edit: March 01, 2020, 01:38:49 PM by cujet »
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glort

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Re: Catalytic converter to reduce exhaust odor
« Reply #12 on: March 01, 2020, 08:36:18 PM »

Still seems easier, more certain and cheaper just to run a longer pipe to duct the exhaust to where you can't smell it.
Cat is only going to work at higher outputs when the heat is there, You'll still be smelling the strongest exhaust at startup and also at low loads if it's not piped away.

The thing with a Diesel and a cat is a diesel will be blowing an amount of air/oxygen into the cat that wouldn't be there with an SI engine.
May help it burn although they don't need oxygen so that may make it over heat but I really think it will cool the catalyst.

Small petrol engines have exhaust that makes the muffler nearly glow red and sometimes does. Loading up my 6/1  you could hold the exhaust ( just) 4 Ft from the engine. You would definitely want the cat Mounted as close as you could get it to the engine.

I wonder if you could make the timing a bit later if that would increase the exhaust temp without causing too many other problems and loss of power?

If you get this together, please let us know how it goes. Sounds very interesting.

cujet

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Re: Catalytic converter to reduce exhaust odor
« Reply #13 on: March 05, 2020, 02:33:45 AM »
Any thoughts on where I can find a cheap diesel catalyst that is "real". I can't imagine the $90 diesel catalysts on ebay have any precious metals in them.
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snowman18

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Re: Catalytic converter to reduce exhaust odor
« Reply #14 on: March 05, 2020, 02:54:52 AM »
Any thoughts on where I can find a cheap diesel catalyst that is "real". I can't imagine the $90 diesel catalysts on ebay have any precious metals in them.

Are you really sure you want to try this.

Catalyst poisoning refers to the partial or total deactivation of a catalyst by a chemical compound..