Volkswagen has just unveiled its cleanest TDI engine ever built. Powering the Jetta, this 2.0-liter common rail diesel mill can reduce nitrogen oxide (NOx) emissions by 90 percent thanks to its reservoir catalytic converter. Production is expected to begin in the United States in 2008. Volkswagen had to significantly raise the bar to comply with California's regulations, which limit NOx emissions to 70 mg per mile. In order to reach this magic mark, the German carmaker developed two systems connected to the oxidation catalytic converter and the particle filter in the exhaust system. The system is regularly and automatically cleaned without the driver noticing. Full Article
<div class='quotetop'>QUOTE(Tideland Prius @ Jan 7 2007, 01:56 PM) [snapback]372141[/snapback]</div> Sadly, 90 percent is still dirtier than SULEV. It is however nice to see that the system must comply with the same 150,000 mile duration requirement as the PZEV certification.
I knew you'd have a say in this lol. It may be dirtier but at least it's still cleaner than we remember.
Let's not forget biodiesel, which if used in the '08 TDI would make the engine at least as clean as the Prius. My partner was asked by a Volkswagen dealer if he'd let them check out the engine in his '02 TDI which has been running on biodiesel for three years. To their amazement, the valves that normally get gummed up at 60k-70k were as clean as new and his car has 80k on it. VW has been ambivalent about the use of biodiesel in its engines, but allows 5% biodiesel with no warranty problem. Ironic, because Rudolph Diesel specifically intended his invention to be run on vegetable oil as a way of bringing power to rural areas. Biodiesel is an exciting alternative fuel that can be made from a wide variety of oil sources, including algae. Bob
I believe the hesitancy from VW on boidiesel is due to the fact that a fair amount of it is homebrewed and thus may not meet standard. The concern of a bad batch aside, the fact that it is a stronger solvent than diesel means it will keep the engine cleaner. Plus, 5% is about as concentrated as you can get without worrying about gelling. That's probably the biggest impediment to the use of it long term. Short term, the porperties that keep the engine clean tend to lead to clogged filters and fuel lines in old engines that have built up a lot of gunk in the tank.
<div class='quotetop'>QUOTE(ShellyT @ Jan 9 2007, 12:11 PM) [snapback]373074[/snapback]</div> I think you're absolutely right. No auto manufacturer in their right mind is going to warantee an engine for use with something as amorphous as 'biodiesel' is today. If it becomes commercially available with standard characteristics maybe it would be possible, but if you're going to be rolling your own I just don't see how any manufacturer would be willing to risk it.
Cleanest or not, I still like Honda's solution better. >>"The central element is an aqueous solution called AdBlue (32.5 percent is comprised of urea)" In Honda's new "clean diesel" approach, there is no "tank of urea" (like MB's and VW's). The amonia is automatically generated (periodically) by the engine ITSELF. That is a creative design! With VW and MB's designs, the tank of urea needs to be filled at oil change (if I remember correctly). That's right. You probably HAVE TO go back to your dealer to perform that 'operation'. BTW, it would be interesting to see whose systems is eventually cleaner, MB, HONDA, or VW?. We shall see. I bet my money on Honda.
Now that the temperature is down to about -24 C, I've been stuck following diesel pickup trucks (Ford SuperDuty, Dodge Cummins, etc) and a few TDI cars. PEEEEEEE-UUUUUUUUUUUU my eyes water, talk about a rank stench they give off when cold. Any worse and I'd shove a football up their exhaust pipe.
There is a standard for biodiesel, The Biodiesel Standard (ASTM D 6751) is for properly de-esterified and filtered fuel. I believe that manufactures should warranty vehicles that use fuel that complies with ASTM D 6751. I ran biodiesel in a 2006 jetta tdi with no ill effects. As long as the proper seals are used biodiesel should not present any problems. Proper biodiesel is very different from vegatable oil and the chemical changes that take place during de-esterification make the fuel much more like petroleum diesel. biodiesel.org/resources/oems/ The same goes for ethanol based fuels for gasoline powered vehicles. If the engine isn't manufactured for use with these highly solvent fuels you will have problems. Cheers Cheryl
There is a standard for biodeisel, but it is easy to homebrew which makes it easier to get fuel that doesn't meet the standard. With that possibility, it is easier and cheaper for the manufacturers to put a low biodeisel limit in place for handling warranty claims.
