[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

> > The ECU will see a lower air temp and add more fuel,
> > So all ecu / ecm do this?, hmm wrong.
> OK, maybe some ECUs don't take the air charge temperature, the most
> important correction beside the base fuelling parameters, into account.
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)

> > > oxygen (your turbo is not going to swallow any more air because you
> inject
> > > some water after it, right?)
> > No
> 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.

> > > However, in both types of engines, there is a lot to be gained if a
normal
> > > combustion can be maintained with more boost or compression ratio.
> > If the timing and fuel are correctly adjusted.  (Timing as used here is
for
> > ignition (SI)or fuel injection timing on a diesel)

> Thank you. However, under some circumstances, detonation starts _before_
you
> have a chance to advance the (SI engine's) spark to the point where that
> engine is the most efficient. You just can't reach maximum brake torque.

There's only dozens of reasons for that, I miss your point here.

> This is obvious on the dyno when you _feel_ there is more (and you
actually
> gain something by advancing the spark a bit more) but you start hearing
some
> random detonation, for example one erratic 'shot' every two-three seconds.
> You add one more degree, you watch the torque output raise a few Nm's, and
> the engine starts detonate more frequently, say one shot every 0.5 - 0.8
sec
> or so (it's very erratic, anyway). You can't get to the maximum torque and
> you even back off two or three degrees for safety. A little water helps a
> lot here. How much water? Just what's needed to allow you to reach MBT
> without suffering detonation at that specific load/speed point.

That has nothing to do with when the water is added to the system, cause
your looking in the chamber for the net results.

> > As soon
> > > as you get end gases detonation or, worse, runaway detonation (also
> > referred
> > > to as preignition) the game is over.

> > Runaway?, how about uncontrolled?.  Since a diesel engine uses a form or
> > controlled detonation.

> Heywood describes it as runaway detonation (see, I can read :) Definitely
> uncontrolled indeed.

How can it runaway?.  Extremely poor terminology if he used that.

> > Also, you suggested cooling the IC with NOS, a substance definitely not
> allowed in FIA rallying, water however, is allowed there.
 > They let them drop water on the street, yet gaseous cooling is illegal?.
> > Some set of rules, IMHO.

> As you wrote, they make the rules. That said, the water is sprayed toward
> the IC using several nozzles, in a fine mist. The spray bar is activated
> only a second or two at a time, only when the ECU decides it's too hot
> (there is various schemes). Rally cars tend to have some protection under
> the engine, front drivetrain, intercooler and radiators thus very little
> water, if any, will ever reach the ground. Also, 2/3 of the championship
(or
> so) are made on gravel or snow.

Was wondering when you get around to that.

> >> It is reasonable to think that if you inject close to the valve, less
water
> >> will evaporate outside of the engine, thus less oxygen will be displace
d.
>>> In contrast, injecting before the IC obviously gives much more time for
the
> >> water to turn to vapor and thus displace more oxygen.
> > But, you said **any** Oxygen displacement was bad.
> I feel like you want me to say there will always be some evaporation
outside
> the engine. Sure, there will and it is bad. Thus the attempt to minimize
the
> 'damages' by injecting water as late as practically possible. IMHO, the
best
> thing would be to use a detonation-resistant fuel, raise boost up to the
> point of diminishing returns and get rid of WI altogether.
> In the future, I'm thinking to experiment further with water injection
using
> a dedicated sequential ECU, in phase with the engine cycles, using regular
> injectors mounted close to the port instead of a modulated but continuous
> flow with nozzles in the intake pipes. This will hopefully allow me to
> precisely meter the flow and inject at the right time in the intake cycle,
> inlet valve open (unlike the fuel, but this is another topic).

ME, overkill, IMHO.
Get so clever and precise, anything slightly wrong and total system shut
down.  Nope.
Grumpy
>
> Axel
>
>
>
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