http://www.burnveg.com/forum/about266.html
SunWizard states:
"This is another reason why RUG blending isn't as good as using Kerosene or Diesel.
Lower auto-ignition temps than 410F fuels advance the timing, higher ones retard the timing. Chart here:
http://www.engineeringtoolbox.com/fuels ... d_171.html "
I'm trying to argue against his statement even though i don't know what I'm talking about. I am trying to learn so bare with me.
SunWizard wrote:roverhybrids wrote:Flash point is the "point" based on temp where a gas can be ignited. Ignition can come from a spark or flame as well as a high heat source(which in our application is hot air from compression)
Flash point is based off of vaporization, which RUG does at much lower temps than diesel.
So as my brain is trying to logicise, the low flash point of RUG allows it to further vaporize reaching the point of AIT sooner than diesel, even given diesels lower AIT??
No, study flash point further, even stated at the link I gave above. It requires a flame or spark to ignite. Hot air won't do it. This is why there are different figures for flash point and AIT. If what you are saying is true, then the AIT would always equal the flash point (if the flash point were lower.)
All of the fuels vaporize long before they auto-ignite. AIT is igniting vapors always.
RUG causes knocking but only because it explodes rather than the slower, more powerful burn you get from WVO or Diesel. But the explosion and knocking from RUG which can damage your engine occurs later (more retarded) than the same amount of Diesel in a blend.
But this is not the main point of this thread, which is that WVO retards your timing, making a quieter engine. Adding RUG causes a whole different knock, so the sound is no longer an indicator of whether your timing is retarded.
Some of my reasoning for discussing this is that I know on my vehicle(04 Dodge commonrail) that is will not cold start on P100 or anything close to that. Blends with diesel in the 50% range had hard start with lots of smoke. I know people that are using blends in this vehicle that include 5% RUG (amoung other things) and they are at least having success in the short term all stating it runs better than on diesel. So the RUG is definately helping it start, perhaps even burn better, if so why?

