Woke up this morning to 22°F weather and a little bit concerned that my VW Passat might not start. We’ve tested down to 28°F, but haven’t been this low running B100 on any vehicle yet.
So I unlocked the doors, which were a bit sticky from the cold weather, and looked at the 1L control group bottle of B100 laying in a box in the back seat. It was almost solid. Uh oh. The fuel gauge showed the tank was only 1/4 full, so I wasn’t sure if there was enough mass to have kept it liquid overnight. Certainly 1L didn’t seem to be enough to stay fluid in the cold.
I sat down in the driver’s seat, turned the key to get the glow plugs going, after 5 seconds, I turned the ignition. It started! I shut the door and drove off into work. So far, so good.
We’re running B100 in all of our company fleet trucks and personal diesel vehicles, in an attempt to remove some of the doubts cast by problems with animal fat biodiesel that was used in the Carolinas last winter, causing many fuel gelling problems. Based upon the control group biodiesel sample this morning, I think we may be at the bottom of the temperature scale without adding anti-gel compounds or blending with petro-diesel, but I was happy to see that I could get into work this morning running B100 in 22°F degree winter weather.
UPDATE (Jan 18, 2009): Okay, so I woke up yesterday morning and it was 9°F. I knew from the previous day that 100% biodiesel was going to be risky at these low temperatures, so I’d blended in about 20% petroleum diesel (B80). Call me chicken, but I wanted to be able to start my car in the morning and get into work. It started and ran just fine in my finicky VW Passat TDI. That’s good news, since that’s about as cold as it gets here in central North Carolina.
We’ve been doing some extensive cold weather biodiesel additive testing recently, and have found that our current addative, Stantadyne Winter 1000, works pretty well, but there are some better alternatives that can reduce the gel point even further. I’ll post more information about it in another article once we have more data.