Final Analysis
I went to San Francisco last weekend for the 2009 Sustainable Biodiesel Summit.
I gave a presentation on my experiences with B100 in my 2009 Jetta TDI (which were also
summarized in biodieselSMARTER magazine).
We also invited Gary Parsons from Chevron to present about the Diesel Particulate Filter technology, which seems to be the problem in 2007.5 and later diesel vehicles. He gave a very deep technical presentation which was very eye opening and very sobering.
The problem with the DPF system is not the DPF itself, but the technology used to implement the regen cycle to clean out the crud. Ironically, the crud builds up only half as fast with B100, but that doesn't solve our problem.
The system employed by Volkswagen, and almost every other OEM today, is called "Late Post-Injection". During the exhaust stroke, some fuel is squirted into the cylinder, which is then vaporized and sent down the exhaust stream. The theory is that it will combust, burning off the crud in the DPF.
The problem is, some of the fuel (ANY fuel) gets down into the crankcase and mixes with the oil. When using regular diesel, this not a big problem because it has a relatively low evaporative point. That means it evaporates out and exits through the positive crankcase ventilation system. It is a known issue that this happens even with diesel, but is not considered a major issue as long as normal oil change intervals are observed.
Furthermore, Gary described in great detail the level of interaction between fuel system, lubrication system, and emissions system that modern vehicles have. He showed charts of permissible emissions and how that "ever-shrinking box" of allowed emissions has increased the level of coordination between the various companies. For example, engine oil manufacturers designing oil for 2007+ vehicles must make their oil withstand the various types of acid that build up in engine oil now that all the sulfur is gone (sulfuric acid used to be the big problem with regular and LSD).
Here comes the problem: with biodiesel having a much higher evaporative point, the amount that gets in the engine oil STAYS there. This has a side effect of making the blend of biodiesel in the engine oil much higher over time - they showed a test where someone fueling with B5 was shown to have B40 in the engine oil. And because biodiesel is even more "polar" than some of the lubricating agents in engine oil, it displaces them, increasing wear over time as the oil breaks down. There has been no long term studies done on this, but if you're expecting the engine to last 500k miles and it only last 300k, that's still a problem.
So, the conclusion: VW has built a system that is simply not compatible with high-blend biodiesel. The engine has no trouble with it, but the emissions system is highly dependent on having the properties of D2 as the DPF regen catalyst.
Where does this leave us? As a group of people wanting to use the highest possible blend of biodiesel - very disappointed. Further testing of real world oil samples may find an optimal blend level, or an acceptable oil change interval. Working around this issue is possible with the effort of many over a long period of time. SOLVING this problem is possible with the OEMs redesigning their systems to not use this technology (which is really no technology at all, but a cheap way out of redesigning the system by just reprogramming the injector system). Caterpillar is already using a different system, which has been shown to work great with biodiesel. The problem is it's prohibitively expensive ($7000 per big truck). It's possible that the engineers at VW can work on a solution that is affordable for smaller passenger vehicles.
Although I'm extremely disappointed in the results, I'm glad to report a lot of lessons learned and other positive outcomes:
I discovered that TDIClub is NOT the place to discuss alternative fuels. I'll be discussing things like this on the Infopop forum in the future, and perhaps posting a link here to there if it's warranted. That may reduce the troll-to-signal ratio.
I learned that the new 2009 engine works just fine with B100, just like all the other VW's out there. Once they re-engineer the emissions system, VW will be back on my radar.
Kumar Plocher, of Yokayo Biofuels, started a letter-writing campaign to the major OEM's urging them to work on an emissions system that is fuel-neutral, or as close as possible.
Shared the stage with a major oil company to discuss the issue in front of my peers and hundreds of interested parties. By raising this issue to a national level, I was able to get people thinking about something that hardly anyone knew about just a few months ago.
Learned a LOT about modern emissions systems and what may be coming down the road in years to come.
Became even more sure that the B100 market will eventually begin to shrink. Companies like mine will have to adapt to this new reality and work to get biodiesel mandates and to integrate low blends into the mainstream. High blends will always be there for the educated and dedicated crowd, but unlikely in the numbers that so many of us had hoped for. I thought we'd have an Accord diesel, Toyota Tundra diesel, Nissan Titan diesel, and a bunch of 1/2 ton diesel pickups in 2009. With none of those materializing yet, we can only hope that their development cycles will be long enough to allow for this emission-system incompatibility issue to be acknowledged and corrected by the OEM's.
For anyone who would like to see the outstanding presentation by Gary Parsons of Chevron, it is posted
here.
The Jetta used in my testing was powered by B100 for about 2500 miles, then it got cold so I dropped down to B50. Once I learned that it would not work with B100 for the long-term, I dropped to B5. Now I'm selling the Jetta (see my ad in the classified section) for $23,000. It is still under full manufacturer's warranty.
Thanks to all that contributed in a positive manner. I'd be happy to answer any additional questions, but please spare us negative comments. I hope that my testing has contributed something to TDIClub, and although I don't see myself using this site much more in the future, perhaps there will be a changing of the guard at some point, less trolling in the alt fuels forums, and more advocacy of non-petroleum fuels.