[Diy_efi] Re: (Was) Is E85 worth it? - Biodiesel etc

[WSCowell at aol.com]

In a message dated 02/09/2006 22:02:28 GMT Standard Time,  
torbjorn.forsman at gengas.nu writes:

There  are a lot of different fluids that are called biodiesel today. 
Some of  them, those produced in a Fischer-Tropsch process, are almost 
100 %  equivalent to ordinary petroleum-based diesel fuel. Such biodiesel 
can be  used in any diesel engine without modifications or  problems.





Thanks for your contributions here Torbjorn, you always have useful things  
to say, your experience is very wide.  I haven't heard of this process in  any 
of my reading so far, I'm sure you are right.
 
   Another flavor is the RME and similar fuels. This is vegetable  oils 
which have been chemically modified "estherized". Top  quality RME works 
perfectly in most diesel engines but is said  that it might cause higher 
NOx emissions than petroleum based  diesel, at least in modern engines 
that are optimized for low  emissions
 
The process is "transesterification".  The oil molecules are converted  from 
glycerides (glycerine molecule on the end of the chain) to esters by  
replacing the glycerine part with alcohol in the presence of a catalyst -  usually 
sodium or potassium hydroxide.  Methanol is the preferred alcohol  apparently.
 
As for NOx emissions, every research paper I have read draws slightly  
different conclusions.  Some say it is increased slightly, some say it is  reduced 
slightly.  All agree that the situation is essentially unchanged,  whereas CO, 
HC, smoke and toxins are greatly reduced in a correctly installed  setup.
 
Yes, old cars using conventional rubber fuel hoses show problems with  
deterioration of the hoses if high concentrations f biodiesel are used.   Most 
diesels from about 1997 on have Viton fuel lines, these are not  attacked.  Viton 
hose is available to replace rubber for any car.
 
Yes, fuel quality is always an issue and the assumption that it has been  
made and stored properly is a "given".  There isn't much information out  there 
yet regarding SVO/WVO in the newer "TDI" direct injection and common rail  
engines.  The alternative fuels community is "working on it"! :-)
 
 
As for SVO, there are too many engines out there running over 200,000 km  
without a hitch for me to believe that it's not a mature technology  already.  
Injector coking of any significance appears to happen only in  engines which are 
fed oil of poor quality or not at the correct  temperature.
 
Looks like this one will run and run..... Thanks Torbjorn!
 
Will