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Just curious, does anyone know if VW vehicles running biodiesel pollute just as badly as conventional diesel? If biodiesel is chemically identical to regular d

Just curious, does anyone know if VW vehicles running biodiesel pollute just as badly as conventional diesel? If biodiesel is chemically identical to regular diesel, than I'd guess it would have identical NOx emissions, but I'm not sure if this is the case

bigethan 11y ago
I drove a 2001 TDI Golf for 12 years and used mostly Biodiesel. Not a chemist. The fuels pollute differently, as they aren't chemically identical. Bio creates more soot when it burns as it's not as efficient of a burn. But the main charm is that no/minimal greenhouse gasses are produced by the burning (it's corn oil, not dinosaur oil). But. The new Clean Diesel's aren't very Biodiesel friendly due to the cleaning process requiring a fuel that burns a little better than Biodiesel does. So it is a hassle if you wanted to try Biodiesel in your Clean Diesel. Not many people were trying it according to the folks at Dogpatch BioFuels, enough so that they looking to find new buyers for their fuel. I don't know what matters most to the EPA, and what VW was cheating at, to know if the defeat device in a Bio car does worse things to the environment.
- TheCondor 11y ago
  Pretty sure biodiesel emits carbon when it burns, the charm is that it's renewable, so long as we can farm vegetables. It's not carbon that was sequestered in the earth but it's still carbon
  - bigethan 11y ago
    Yep that's the soot part I mentioned.
- jhayward 11y ago
  > The new Clean Diesel's aren't very Biodiesel friendly due to .. The only biodiesel restriction I'm aware of in larger (e.g., 3/4 to 1 ton pickups) is related to the amount of water bound to glycerin in the fuel. Common-rail injection systems are very finicky and any above-design-limit water can cause corrosion which damages the injectors or fuel pump. My truck is certified for only 5% (B5), newer ones are B20 certified. The only difference is the fuel system. I've not heard of any emissions impacts.
ptaipale 11y ago
I expect biodiesel fuels pollute more when they are burned (and they have some downsides in the production side as well). (Someone around here was driving his old Mercedes using leftover fries cooking oil from a local McDonald's. He had to stop it, but not due to pollution, but for tax reasons. The government really hates losing that revenue.)
fnordfnordfnord 11y ago
IIRC Biodiesel has higher NOx emissions but lower particulates. Here is a ppt which I haven't even read yet. http://www.nrel.gov/docs/fy05osti/38296.pdf http://www.nrel.gov/docs/fy05osti/38296.pdf
selimthegrim 11y ago
It dilutes the crankcase oil on the new TDIs due to the difference in boiling point, and it gums up the DPFs, voiding the emissions warranty.

bigethan 11y ago

I drove a 2001 TDI Golf for 12 years and used mostly Biodiesel. Not a chemist. The fuels pollute differently, as they aren't chemically identical. Bio creates more soot when it burns as it's not as efficient of a burn. But the main charm is that no/minimal greenhouse gasses are produced by the burning (it's corn oil, not dinosaur oil). But. The new Clean Diesel's aren't very Biodiesel friendly due to the cleaning process requiring a fuel that burns a little better than Biodiesel does. So it is a hassle if you wanted to try Biodiesel in your Clean Diesel. Not many people were trying it according to the folks at Dogpatch BioFuels, enough so that they looking to find new buyers for their fuel. I don't know what matters most to the EPA, and what VW was cheating at, to know if the defeat device in a Bio car does worse things to the environment.

TheCondor 11y ago
Pretty sure biodiesel emits carbon when it burns, the charm is that it's renewable, so long as we can farm vegetables. It's not carbon that was sequestered in the earth but it's still carbon
- bigethan 11y ago
  Yep that's the soot part I mentioned.
jhayward 11y ago
> The new Clean Diesel's aren't very Biodiesel friendly due to .. The only biodiesel restriction I'm aware of in larger (e.g., 3/4 to 1 ton pickups) is related to the amount of water bound to glycerin in the fuel. Common-rail injection systems are very finicky and any above-design-limit water can cause corrosion which damages the injectors or fuel pump. My truck is certified for only 5% (B5), newer ones are B20 certified. The only difference is the fuel system. I've not heard of any emissions impacts.

ptaipale 11y ago

I expect biodiesel fuels pollute more when they are burned (and they have some downsides in the production side as well). (Someone around here was driving his old Mercedes using leftover fries cooking oil from a local McDonald's. He had to stop it, but not due to pollution, but for tax reasons. The government really hates losing that revenue.)

fnordfnordfnord 11y ago

IIRC Biodiesel has higher NOx emissions but lower particulates. Here is a ppt which I haven't even read yet. http://www.nrel.gov/docs/fy05osti/38296.pdf http://www.nrel.gov/docs/fy05osti/38296.pdf

selimthegrim 11y ago

It dilutes the crankcase oil on the new TDIs due to the difference in boiling point, and it gums up the DPFs, voiding the emissions warranty.