Diesel Catalytic Converter

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moose60
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Diesel Catalytic Converter

#1

Post by moose60 » 13 years ago

My understanding is that catalytic converters used on diesels must not get much sulfur. Or am I confusing cats and PM traps? With our recently 15ppm max sulfur diesel (or BD) this should not be a problem for either. Is this correct?
I'm wondering about the sulfur content of Canadian and Mexican diesel. I'm guessing that Mexican diesel is still high sulfur.

-later-


from- http://www.dieselnet.com
Mexico has two grades of automotive diesel fuel:

* Low sulfur grade (Diesel Sin) of 0.05% = 500 ppm sulfur content, and
* Standard grade of 0.5% sulfur content.

The “Diesel Sin” grade (0.05% S) was first introduced in Mexico City and then in selected other urban areas including Guadalajara and Monterrey. It gradually replaces the standard 0.5% diesel nationwide.


From- http://www.howeslube.com
We would like to inform you about some differences between U.S. and Canadian ULSD requirements. As of June 1, 2006, all production in Canada of diesel fuel must be less or equal to 15 ppm (ULSD). By September 1, 2007, only ULSD fuel is allowed to be sold at the retail level. There was an amendment proposed to follow the margin of error allowance amendment enacted in the EPA version, up to 22 ppm diesel, from September 1st to October 15th, but as of this writing it has not been enacted in Canada.



So, Mexico still sells what we used to have, and Canada has the same sulfur concentrations as the US.
Byron

82 Datsun 720 KC SD22

MPG Machine

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asavage
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Re: Diesel Catalytic Converter

#2

Post by asavage » 13 years ago

moose60 wrote:My understanding is that catalytic converters used on diesels must not get much sulfur. With our recently 15ppm max sulfur diesel (or BD) this should not be a problem for either. Is this correct?
Yup :D

My understanding is the the NOx conversion efficiency may not be as effective if there is a lot of excess oxygen -- though I might have that wrong. NOx conversion definitely needs to operating in a reducing environment.

That may have NOx conversion efficiency implications for my turbo LD28 project. But I'm still going to add one.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

glenlloyd
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Re: Diesel Catalytic Converter

#3

Post by glenlloyd » 13 years ago

moose60 wrote:My understanding is that catalytic converters used on diesels must not get much sulfur. Or am I confusing cats and PM traps? With our recently 15ppm max sulfur diesel (or BD) this should not be a problem for either. Is this correct?
I'm wondering about the sulfur content of Canadian and Mexican diesel. I'm guessing that Mexican diesel is still high sulfur.

-later-


from- http://www.dieselnet.com
Mexico has two grades of automotive diesel fuel:

* Low sulfur grade (Diesel Sin) of 0.05% = 500 ppm sulfur content, and
* Standard grade of 0.5% sulfur content.

The “Diesel Sin” grade (0.05% S) was first introduced in Mexico City and then in selected other urban areas including Guadalajara and Monterrey. It gradually replaces the standard 0.5% diesel nationwide.


From- http://www.howeslube.com
We would like to inform you about some differences between U.S. and Canadian ULSD requirements. As of June 1, 2006, all production in Canada of diesel fuel must be less or equal to 15 ppm (ULSD). By September 1, 2007, only ULSD fuel is allowed to be sold at the retail level. There was an amendment proposed to follow the margin of error allowance amendment enacted in the EPA version, up to 22 ppm diesel, from September 1st to October 15th, but as of this writing it has not been enacted in Canada.
Is agricultural use considered retail? I haven't done much digging but the language suggests that non-road diesel is not held to the same standard. Does anyone know if this is the case? Does anyone know what percentage of total diesel used in the US is considered non-road?

thx
steve a
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!

moose60
Posts: 168
Joined: 14 years ago
Location: Seattle WA

#4

Post by moose60 » 13 years ago

Al,
My understanding is that Cat efficiency re: NOX really dives with O2 above 0.5%, and the cat will stop working around 1.0% O2 in the exhaust. Wikipedia has a decent section on cats. I think that this is why NOX reductions have been tough on diesels (ie: unthrottled intakes).

The link to "Discount Converters" that you posted earlier (in the generator thread) shows information that their cats can provide dramatic reductions in NOX on diesels. I called them this morning, and the man on the phone said that stationary engines had been used for the testing. I said, "So, they basically tuned the crap out of the test engines in order to get the most dramatic reductions for their test results?" He said, "Yep, pretty much. They don't test 'em on road-going vehicles, and they run at a constant RPM."

Hmm...

Steve,

I believe that Ag diesel, or off road (dyed) diesel is much higher sulfur than what we see at the pump. I looked into this a year or two ago, so I don't remember specifics.
Byron

82 Datsun 720 KC SD22

MPG Machine

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asavage
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#5

Post by asavage » 13 years ago

I've read several people who've typed that Ag diesel is exempt from ULSD (as well as road taxes, of course).

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asavage
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#6

Post by asavage » 13 years ago

moose60 wrote:My understanding is that Cat efficiency re: NOX really dives with O2 above 0.5%, and the cat will stop working around 1.0% O2 in the exhaust. Wikipedia has a decent section on cats. I think that this is why NOX reductions have been tough on diesels (ie: unthrottled intakes).
Still, light-duty diesel pickups in the US have been running cats for several years, and I kind of doubt it's to clean up HC/CO emissions, but I admit that's only a guess.
Regards,
Al S.

1982 Maxima diesel wagon, 2nd & 4th owner, 165k miles, rusty & burgundy/grey. Purchased 1996, SOLD 16Feb10
1983 Maxima diesel wagon, 199k miles, rusty, light yellow/light brown. SOLD 14Jul07
1981 720 SD22 (scrapped 04Sep07)
1983 Sentra CD17, 255k, bought 06Jul08, gave it away 22Jun10.

glenlloyd
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Location: Des Moines, Iowa
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#7

Post by glenlloyd » 13 years ago

asavage wrote:Still, light-duty diesel pickups in the US have been running cats for several years, and I kind of doubt it's to clean up HC/CO emissions, but I admit that's only a guess.
I have wondered about this, many dealers here in the mid-west were making a big deal out of the remaining '06 non-cat diesel trucks they had in stock when the early '07's were coming out. Perhaps these weren't considered light duty.

steve a
97 Jetta TDI, 86 VW Golf D
89 VW Fox diesel, 92 MB 300SD W140

gir - won't the sploding hurt?
zim - silence!

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asavage
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#8

Post by asavage » 13 years ago

The issue with big trucks is EGR (NOx reducing) in combination with PM oxidizers and traps. This is going to be hard on the lube oil: EGR = increased lube oil soot.

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