[Gasification] Prime Mover Knock

[Arnt Karlsen]

On Tue, 16 May 2006 13:38:52 +0100, AJH wrote in message 
<5qhj621rvmkr0ievcunt7oq2eim8nkn9q8 at 4ax.com>:

> On Tue, 16 May 2006 01:37:45 -0400, Jeff Davis wrote:
> 
> >Early diesels used fuel injection by high pressure air. This atomized
> >spray,  into the cylinder, made a soft combustion hense slower rate
> >of pressure rise  after injection started. No diesel knock was heard.
> 
> Jeff, this was about the biggest mistake Rudolph Diesel made, it was
> not rectified until a brit introduced fuel injection. I have seen one
> of his early Sulzer's running at "internal fire museum" in Wales.
> 
> If you think about it using a compresses air blast is about the worst
> think to do, in effect you are expanding an ambient temperature gas

..if you cool it far enough down, yup.  Is why you'll need some start up
system for the cold engine.

> into the hot post compression gas in the cylinder, this expanding
> blast robs heat from the combustion chamber and slows combustion. This
> produced the soft effect you describe but a high efficiency cost.
> 
> Also consider that there was a big power cost in adiabatic compressing
> gas for the reservoir and then cooling it to maintain capacity, all
> this power was just converted back to heat which was lost.
> 
> Similarly the indirect ignition diesels sacrificed efficiency for
> smoothness in passenger vehicles but big engines always seem to have
> favoured direct injection.
> 
> It's the move to common rail and high pressure injection systems with
> electronic control that has enabled direct injection diesels to become
> refined without sacrificing efficiency.

..aye, but can these handle wood powder as neatly as Jan Åbom's air
blast wood powder diesel?  

-- 
..med vennlig hilsen = with Kind Regards from Arnt... ;o)
...with a number of polar bear hunters in his ancestry...
  Scenarios always come in sets of three: 
  best case, worst case, and just in case.