[Vwdiesel] Diesel working on liquid propane

[Roger Brown]

On 10/12/2010 3:32 PM, Roger Brown wrote:
> On 10/12/2010 2:09 PM, Tad wrote:
>>>  From what I recall reading on the TDIClub forums several years back, propane
>> on a diesel tends to have a similar effect as nitrous oxide on a gasser.
>>    Obviously not the same in that there's no O2 in propane, but it tends to
>> accelerate the progress of the slow-burning diesel flame front, increasing
>> efficiency in the process.
>
> I think the main thing is that it is a cleaner burning fuel than diesel.  W/ diesel only,
> you can never really get to the stoich. air/fuel ratio as the burning diesel will start to
> make too much soot (like heavy black smoke).  So the idea is adding a small amount of
> cleaner burning fuel to the intake to take advantage of that excess oxygen you have gone
> to the trouble of sucking into the engine and compressing to make a little extra power
> with.  The trick is to keep the propane percentage well below the flammability limit which
> is about 10% (10:1 air/fuel ratio) to keep it from detonating during the compression stroke.

Correction, misread the chart, the flammable range for propane is 2.1% - 10.1%, so you 
need to stay below lower limit AFAIK.
	http://www.engineeringtoolbox.com/explosive-concentration-limits-d_423.html
And liquid propane in a tank is under almost 200psi at around 100F:
	http://www.engineeringtoolbox.com/propane-vapor-pressure-d_1020.html

-- 

   Roger