This was just posted by Doug Williams in response to a question about water injection and Producer gas.
I have just returned from overseas travel, and see your question.
>i don't remember seeing any disucssion here on water/steam injection
> into an ic motor running on wood gas. so far in the books i've not
> come across it either, but it is likely there, as i've yet to finish
> all the books. anyways, water injection would seem to help much with
> several liabilities of woodgas fired ic engines.
All those engines which had water injection, were gasoline fuelled, the
highest form of heating you can get in an engine situation. Producer gas is
one of the lowest heating fuels, and if you put water or steam into this
gas, it will slow the flame speed right down, not crack into hydrogen and
oxygen as normal for the gasoline fuelled engine.
The result is that the gas is still burning as it exits the exhaust causing
burnt valve seats. Catalyitic converters would seem to be nessesary to avoid
CO emissions from most engines using producer gas as fuel. As for servier
liabilities, this only applies to high speed engines, say operating over
1800 rpm, when the high torque capability is lost. Slower speed engines can
do real justice to this very misunderstood gas.
Hope this helps,
Doug Williams,
Fluidyne Gasification.
I have just spent two weeks standing next to a five cylinder 62 litre 600
RPM dual fuel engine running on producer gas. This was the first time that I
have worked with engines of this size, but in the end, all engines work the
same on producer gas. In the past, I have often read that high diesel
replacement of up to 90% has been achieved, but from our own experience,
only managed 82.23% under perfect conditions. It was therefore a surprise to
actually be told by the engine specialist on site, that our big engine was
operating at 94% replacement of diesel, but there is a twist to this
statement.
When originally supplied for it's intended purpose as a base load stand-by
generator, the engine was sized 20% bigger than the actual rated out put of
the generator, effectively setting the engine to be operating at 80% of the
normal rated out put on diesel. At this 80% out put, it is the maximum point
of dual fuell efficiency, so when operating on producer gas, it litterally
just shut down the injector pump, relegating the diesel to fullfil the role
of a spark plug. The sound was like the hit and miss of a faulty spark plug,
and the acceptable way of operating these engines on dual fuel. The actual
diesel fuel flow was less at maximum out put, than required to just idle the
engine on no load.
Without a doubt, the fly wheel is the reason that allows this high
replacement, along with the slow speed, so it should be understood, that the
smaller, higher speed engines, just do not have the innertia to get that
higher replacement %. I should also mention that I had the oppertunity to
confirm the accuracy of the Fluidyne Engine Tables
www.Fluidynenz.250x.com making it easy to see what you can get out of the engine in front of you.
Clearly the slow speed engine with a big fly wheel, has advantages fuelled
on producer gas, and if the load can be kept constant, will do justice to
maximizing diesel replacement. I really admire your tenacity to make those
Listeroids perform as your need dictates.
Doug Williams,
Fluidyne Gasification.
SLOW SPEED, that is the solution to biomass fueling of IC engines. If there was ever a more practical enigine than the DI Lister clone or Petters for producer gas I haven't seen it.
Doug ( not the guy from Auz )
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