BioDieselNow - Renewable biodiesel fuel

http://biodieselmagazine.com/article.jsp?article_id=2290&q=&page=all 

I assume this is a typo, and they really know what they are talking about...

A New Understanding of Biodiesel’s Dilution Effect
Volkswagen is using post-injection for regeneration and according to Stuart Johnson with the Engineering and Environmental Office of Volkswagen Group of America, the issue of oil dilution from biodiesel is a real concern for the automakers. “We can tolerate up to 50 percent fuel mix in the oil but no more,” he said at the 2008 National Biodiesel Conference.

Volkswagen tests using B5 and post-injection showed 45 percent oil dilution after 10,000 miles, but surprisingly no engine damage was evident upon inspection. “Using B10 at 10,000 miles surpasses that 50 percent threshold—and that is unacceptable,” Johnson said. “We want longer oil change intervals as a car company, so it’s hard for us to talk about this.” The implications are that increased fuel dilution due to biodiesel blends could lead to premature engine wear if oil changes are not done more often.

Senior technical advisor for Cummins Inc., Howard Fang, explains to Biodiesel Magazine exactly how this inordinate accumulation of biodiesel in the crankcase oil takes place.

Cummins has done extensive work to characterize biodiesel’s effects on engines, performance and exhaust. “Biodiesel definitely promotes fuel dilution,” Fang says.

This error is repeated three more times.  And they conclude with this:

Even though for years biodiesel has been heralded as a lubricity additive helping keep fuel system components like the moving parts inside fuel injection systems operating smoothly, the bitter irony here is that, when post-injected, it tends to dilute engine oil and interacts with additives and increases the possibility of engine wear. Much work remains developing viscosity improving, anti-wear, dispersant and detergent additive packages in which adverse reactions with biodiesel are significantly reduced.

Cynic that I often am, the thought of who is funding this young Phd candidates research immediately crossed my mind.  Hmmmm . . . .  - probably nothing, but it wouldn't be the first time a desired result is forecast by the appropriate funding source.

I too would be interested in the same analysis on ULSdinoD.

I think the statement about dilution of the oil applied ot any fuel, not just BD.  it's jsut that due to the properties of BD, more of it gets into the oil.

I'm planning to do some testing on this to determine at what mileage I should change my oil. 

I'm going to collect my ODBII/CAN data over time so I can determine my regens using one of those ODBII/CAN data loggers and then get my oil tested after each regen by Blackstone Labs.

I've already ordered some test kits.  I'll baseline my oil as soon as I get the first kit.  The Jeep only has 350 miles on it right now.

Then I'll test about every 1000 miles. Each test should include at least one regen.  If the use of BD spaces them apart, then I'll have fewer labs to pay for.  I'll make sure they check for oil dilution.  I'll see how long it takes to get to a 30% dilution using normal dino oil.

Then I'll step up to 5% (required in all pumps in Portland, OR).  When I get to 30% dilution I'll go to 20%, etc.

This will be a long term test given we only put about 10k miles a year on a car.  I'll post results as I get them.

magconpres:

I think the statement about dilution of the oil applied ot any fuel, not just BD.  it's jsut that due to the properties of BD, more of it gets into the oil.

I'm planning to do some testing on this to determine at what mileage I should change my oil. 

I'm going to collect my ODBII/CAN data over time so I can determine my regens using one of those ODBII/CAN data loggers and then get my oil tested after each regen by Blackstone Labs.

I've already ordered some test kits.  I'll baseline my oil as soon as I get the first kit.  The Jeep only has 350 miles on it right now.

Then I'll test about every 1000 miles. Each test should include at least one regen.  If the use of BD spaces them apart, then I'll have fewer labs to pay for.  I'll make sure they check for oil dilution.  I'll see how long it takes to get to a 30% dilution using normal dino oil.

Then I'll step up to 5% (required in all pumps in Portland, OR).  When I get to 30% dilution I'll go to 20%, etc.

This will be a long term test given we only put about 10k miles a year on a car.  I'll post results as I get them.

 

You must have missed a couple of things when you read it. 

old300D:

What properties of biodiesel would lead you to conclude it would be more likely to dilute the engine oil more than petroleum diesel?

From the article:

"Because biodiesel has a higher distillation temperature and boiling point, when it’s present in the post-injected fuel it tends to dilute the oil on a level disproportionate to its blend ratio in the fuel."

Using B20: 

"Fang asserts. “The problem is in all IR, GC—any analytical technique really—you assume the concentration is B20 but because ultra-low sulfur diesel (ULSD) is easier to vaporize, the concentration of biodiesel on the cylinder walls is higher than 20 percent, maybe way higher.” In fact, Fang has developed a method to more precisely measure this and found that post-injected B20 can lead to as much as 40 percent methyl ester accumulation on the cylinder walls."

old300D:

The only thing I got from the article was that somehow biodiesel breaks down the engine oil additives more than petroleum diesel, but there were no mechanisms suggested for this effect,

“Look at all of these additives,” Fang says. “They are all bipolar molecules—one side of these molecules is very polar while the other is nonpolar. The nonpolar tail is used to sustain the polar head and make it suspended in the oil, which is largely nonpolar.” So the additives are relatively polar compounds compared with the base oil, and methyl esters are polar as well. Polar molecules are attracted to polar molecules, so biodiesel in the oil is attracted to the likewise polar additives. “We used spectroscopy to quantify this,” Fang says. “The more polar the additives, the more they interact with the biodiesel. And if the biodiesel gets degraded, or experiences thermal or oxidative aging or whatever, the biodiesel will absorb more oxygen and become even more polar, which will generate even more interaction with the additives.”

Sounds like post-injection was a quick fix and a temporary one.

Martin 

 I heard something about vo derived engine oil, anyone else know about this.  I would think that it would mix better.

perotter:

Sounds like post-injection was a quick fix and a temporary one.

Too bad since it won't be temporary for me.  I generaly keep a car for about 10 years.  If I can't run BD in it though, I'll have to trade it for something I can.  Maybe an 09 if they come out with the Cummins and a different regeneration process.

In any case, I'm taking my first oil sample today to use as a baseline.  I had planned to run pure diesel, but thin I'll just start with B5 since it si covered by the warrantee.