Biodiesel and diesel particulate filters

[Suzy Member Find all posts View Profile Close Suzy]

One of the "reasons" not to use biodiesel that's often touted is that it'll clog your diesel particulate filter. The myth goes as follows:

Biodiesel burns at a lower temperature than petrodiesel, so the exhaust temperatures don't get high enough to allow the particulate filter to burn off the accumulated soot. Eventually, the particulate filter fills up, and Peugeot/Mazda/VW charge many thousand dollars to replace it.

This is something that I'm concerned about, as my car (a Pug 307) has a particulate filter (aka FAP) and I'm running it on biodiesel. Up until now, I've reasoned that the lower particulate emissions from biodiesel (approximately 50% according to the EPA) mean that the particulate filter isn't going to be overly taxed, so it probably won't be an issue.

However today I found a reference to a study that found that the soot from biodiesel has a higher oxygen content than that of petrodiesel. This means that the temperature at which biodiesel soot burns is substantially lower than for petrodiesel. They found that the "balance point tempetature" - the temperature at which the filter is able to regenerate passively, is reduced by 112 degrees C compared to petrodiesel.

Neat, huh. That blows the only argument that had any shred of credibility against using biodiesel in my pug away completely.

An article reporting on the study is at: Green Car Congress: Biodiesels Beneficial Effect on Diesel Particulate Filter Performance

[TroyH Senior Member Find all posts View Profile Close TroyH]

Re: Biodiesel and diesel particulate filters

I wonder if it has come from using biodiesel and not setting up the engine to run on it? Just wondering that since a blend of bio and petro gives a reduction in particulate matter, but B100 seems to give an increase.

"Biodiesel fuel may have the potential to reduce our nation's reliance on imported oil and to improve air quality," said Mridul Gautam, Ph.D., a professor in the university's Department of Mechanical and Aerospace Engineering and one of the authors of the study. The scientists studied a blend of 35 percent biodiesel fuel and 65 percent conventional diesel fuel. They found that this emitted significantly less carbon monoxide and moderately less hydrocarbons and particulate matter, compared to 100 percent petroleum diesel.
"The potential of biodiesel to reduce emissions is quite significant," says Gautam. "There is a 25 percent reduction in particulate emissions alone." Emissions of carbon monoxide declined by 12 to 14 percent, and hydrocarbons by 10 percent, he added.
Biodiesel fuel is made by a reaction of vegetable oils with methanol or ethanol. The result is a less viscous, more volatile fuel. The truck engines ran just as efficiently on the biodiesel mix as on conventional diesel fuel (i.e., the average miles per gallon were essentially the same).
The research team found slightly elevated levels of nitrous oxide (NOx) emissions with the biodiesel blend. Changing the ignition timing of the engines reduced NOx emissions.
The reduction in carbon monoxide emissions is probably due to the higher oxygen content of the biodiesel fuel, the researchers say. More oxygen means the fuel is burned more completely. More complete burning also helps reduce hydrocarbon emissions.
The researchers attributed the 25 percent reduction in particulate emissions to the lower aromatic and sulfur content of biodiesel fuel, and its greater oxygen content.

ScienceDaily: "Biodiesel" Fuel Could Reduce Truck Pollution

Table 2.Engine emission results from the University of Idaho. __________________________________________________ ________
Emission 100% Ester Fuel (B100) 20/80 Mix (B20)
__________________________________________________ _______________________
Hydrocarbons - 52.4% -19.0%
Carbon Monoxide - 47.6% -26.1%
Nitrous Oxides - 10.0% -3.7%
Carbon Dioxide + 0.9% +.7%
Particulates + 9.9% -2.8%
__________________________________________________ _______________________

Biodiesel Fuel

[Suzy Member Find all posts View Profile Close Suzy]

Re: Biodiesel and diesel particulate filters

I wonder if it has come from using biodiesel and not setting up the engine to run on it? Just wondering that since a blend of bio and petro gives a reduction in particulate matter, but B100 seems to give an increase.

That contradicts with what the EPA said:

http://www.epa.gov/OMS/models/analys...dsl/p02001.pdf

See page 4 for a summary graph. PM decreases as biodiesel concentration goes up - 12% decrease for B20, 28% for B50, and 48% for B100.

[TroyH Senior Member Find all posts View Profile Close TroyH]

Re: Biodiesel and diesel particulate filters

well there you go!

Just goes to show that different experimental design can give different results. I was actually under the impression that particulates reduced in the trend the EPA report described, and said as much in my post, until I read properly the table in the link I posted (which disagrees), so I went back and changed it!

Don't think I've seen this study before. Will have to go and have a read through it. Thanks!

[Robert Administrator Find all posts View Profile Close Robert]

Re: Biodiesel and diesel particulate filters

I think some of us need to find where our particulate filters live, how they can be removed/inspected/replaced and do some of our own anecdotal research.
I've just bought a Mazda 6 diesel and I'd love to test this out for myself.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Biodiesel and diesel particulate filters

From my reading of how they are supposed to work, I would expect that a particulate filter should be on the exhaust pipe, very close to the manifold.

Hope this helps,
Tony

[zigparacingtadpole Senior Member Find all posts View Profile Close zigparacingtadpole]

Re: Biodiesel and diesel particulate filters

From the outside they look a lot like a cat converter on a petrol vehicle (no not the tyres, thats for converting the other other type of cat). I'm guessing they probably only look alike and are quite different inside.

[Tygar Biofuels Forum Newbie Find all posts View Profile Close Tygar]

Re: Biodiesel and diesel particulate filters

For an excellent explaination of how the filters in Peugeots and Citroens work, see this presenation from PSA.
The important thing about FAPs or DPFs in these cars is that they are Active and require an additive to the fuel to assist in the active regeneration.
I have also seen a report that these additives affect the oxidation of neat biodiesel (B100) in a negative way.
This may not affect B100 or blends that conform to AUS standard but may be an important consideration if you are not using your bio quickly.
Here is the link..
PSA Peugeot Citroen - How things work - The Particulate Filter

cheers Tygar.

[ricracer Biofuels Forum Newbie Find all posts View Profile Close ricracer]

Re: Biodiesel and diesel particulate filters

Bought a 2005 VW Touraeug (dont know how to spell it!) 2.5 tdi to run on B100. Have done about 4000 miles on B100 but it is quite smokey out the side exhaust, I take it is bioideisel burning off. Seems to be really sometimes when stationary. Is it doing any harm or should I move to B50. Any ideas are welcome cheers

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Biodiesel and diesel particulate filters

If you look inthe stickied post http://www.biofuelsforum.com/using_b...eage_time.html there is a member using B50 in a 2.5TDI.
Perhaps you can contact them to see if they went to B100 before making a decision.

[SUZUDDIS Senior Member Find all posts View Profile Close SUZUDDIS]

Re: Biodiesel and diesel particulate filters

Ricracer
I'm interested in the Toureg , was looking at a 2005 5 cyl Diesel. running B100 is of interest to me but I was thinking I may have to heat it before the IP. these cars look fantastic with a nice set of wheels. pimp it.

regarding the DPF and what they look like.
My Suzuki GV DDIS has one. it looks like an ugly buldge in the exhaust just behind the Torbo. it has a fuel line and ignitor plug in the side of it. should also be a sensor in there somewhere. When I run on more than 50% Bio a light comes on the dash. this is something to do with the fact that the car needs to have some highway miles. ??? run it at higher than 80km and it goes away. probably the cleaning cycle.

To remove one of these I think and don't qoute me , but it would be breaking the law.

But I'm told that they can be removed and over ridden. have a look on youtube. seems people are already making kits. something along the lines of 3D movies, just makes things harder to copy. Not that I'd do that

Good Luck

Michael