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

[Bruce Plecan]

> > > But you excluded it in your first statement.
> > > I implied it. The AFR is supposed to be maintained, some way or
another,
> > > with or without water.
> > No you specificly said just timing
> Re-read it. I never excluded anything. I just didn't mention it because it
> is totally obvious, at least to me, that with more boost goes more fuel.
As
> I also said, it's an ECU job and it's been mapped for this.

Bzzt, now your just playing word games.

> > Now,  would you use such an ECU to run a highly tuned race engine, if
> regulation  allows you to use a more sophisticated unit?
> > Lots of other details involved other then the ge wow factor. There are
> > applications were brutialy simple out weights, risking sensor failures.
> (ie experimential aviation, and yes they use fiinely tuned race engines)
> Things tends to get more sophisticated, nowadays, but we jump from cars to
> tractors to airplanes here.

You asked for an example, I gave you one.

 I confess I don't know what kind of combustion
> control (or whatever) is used on rocket engines, nor do I care.

Then why mention it?.

 Now can you
> please mention the name and type of one or more electronic engine
management
> systems likely to be found in a modern turbocharged car, that don't use
ACT
> as an input parameter?

If by ACT, you mean intake air temp in the "plenum",  Buick Gns

> > > No? Are you saying that injecting water in the air charge at some
point
> in
> > > the intake system, after the turbo, will cause the turbine wheel to
> > > accelerate? Please explain.
> > The intake chage by being cooler will have less pressure, in most high
> > performance turbo applications there, is a limiting factor based on
boost.
> > So yes the turbo will be spinning faster.
> So evaporating water will not cause an _increase_ of pressure instead?
> Actually, you just added something (steam) that takes 100% of the room
made
> up by the temperature decrease (like the "pushing a rock uphill"
metaphor),
> and displaced oxygen in the process (the original point of this
discussion).
> So no, the turbo will not be spinning any faster.

To have the same boost, yes it will.

> And, by the way, what is the "limiting factor based on boost"? air speed
at
> the turbo intake? compressor wheel speed? losses in the induction system?
> engine's VE, fuel available? detonation?, exhaust back pressure? turbine
> housing flow?

Depends on engineering, tuning, like you mention can be numerous items.

> > > a dedicated sequential ECU [for WI]
> > ME, overkill, IMHO.
> > Get so clever and precise, anything slightly wrong and total system shut
> > down.  Nope.

> Different point of views.

Nope, again I'm right.  You just fail to see the other view.

> I've read Mr. Harris and Summer's messages with great interest, and also
Mr.
> Colon's answer. I stand corrected, water is not inert and does participate
> in accelerating the combustion process, enabling more energy to be release
> in the short timeframe encountered at high engine speed. It show I'm not
up
> to speed with the thermochemistry of the combustion process, and I learned
> something. Now, what's the engine speed where water start to do something
> mesurably useful?

as you approach max torgue, and continues to max HP

 Does this speed fall in the diesel engines operating
> range? Below that speed, what the water is useful for, beside as an
> in-cylinder coolant and detonation retardant?

Define diesel's operating range..
Grumpy


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