Water injection (was: Re: fuel cooling intake air)

[Seth]

Bruce

I have been watching this thread. I was wondering if you might be a bit
more specific about your application. I have a feeling that the needs of
a spark ignition engine at high rpm might be different from a highly
boosted diesel. I am wondering if at full boost you manage a
stoichiometric air fuel ratio (or fuel rich?) with the diesel, or are
you still very fuel lean as most normal diesels are. And do you have
control of injection timing with respect to manifold pressure?

 I suspect that cooler combustion temps might be a good thing with a
diesel if it it still fuel lean of stoich, so that you aren't combusting
piston tops as well as diesel fuel. In a mixture that has very little
extra oxygen, such as a spark ignition engine, then the displacement of
oxygen is not such a good thing for making power, as a rule of thumb.
The point of the turbo was to get more oxygen in the engine in the first
place, after all. If you are very fuel lean and oxygen rich, then
perhaps this displacement of oxygen is not such a penalty as in a spark
ignition engine. But one could argue that it serves a similar function
as EGR at that point, by reducing peak combustion temperatures. Which
brings us back to why bother trying to force the air in the engine if
you only want to displace it with an inert gas or water vapor.

 I might also say that the point of spraying the water at the
intercooler probably winds up producing water vapor, not puddles, if
done correctly. The commercially available systems I have seen try to
evaporate the water in the air just ahead of the intercooler. Whatever
is left probably boils off. Not saying that others aren't different,
just what I have have seen.


-Seth

Bruce Plecan wrote:
> 
> >This is as much as I
> > want to disclose here.
> 
> Gee, thanks,
> 
> > That said, this game is not going to lead you nowhere. Turning back
> > questions will not make your point.
> 
> Sure, it did, least you answered a few direct guestions.
> I now also know to expect sand bagged answers, from you.
> You want to just play games, instead of discuss things, or think you got all
> the answers fine, I'll play the game.
> 
> > However, I still stand firmly behind what I said: if you let the water
> > evaporate before it enters the engine, you displace oxygen, and no matter
> > how little, this is a bad thing.
> 
> What is water made of?.
> Ah,
> but you didn't say in a reactable form.
> 
> >Also, water do nothing more than prevent
> > detonation, just turning on the water jets does strictly nothing to your
> > torque output.
> 
> Haven't seen anyone claiming that. (unless the motor already is detonating,
> then there will be gains) (diesel applications, again rears it ugly head,
> and your not addressing those).
> 
>  You can however use more spark advance if required, or more
> > boost, and from that comes the gain.
> 
> Fuel is not an element in this, hmm, odd to my way of thinking
> Advance ignition timing in a diesel, who'd thought
> 
>  If cool air is what you want, you must
> > increase the efficiency of the intercooler, spraying water on it being a
> > popular option.
> 
> AGAIN, THIS IS ILLEGAL in some forms of racing.  They (the rulers makes) in
> some forms of racing consider it dangerous to spread liquids on the
> track!!!.   I just as a matter of common sense don't want to be racing on
> asphalt, will some one spraying water on the track.
> 
> BTW, how do you keep any water from evaporating in your system?.  I mean if
> it's such a bad thing, in your opinion.  Would mean that, the whole system
> would have to be at jus over 32dF, or is there some error in your statement
> "you displace oxygen, and" yada yada, or is a gross over statement of
> fact...
> Grumpy
> 
> > Axel
> 
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