Water Injection for power?

[Thor Johnson]

On Tue, 10 Sep 1996, Robert J. Harris wrote:

> > From: Thor Johnson <johnsont at falcon.mercer.peachnet.edu>
> > To: DIY EFI Maillist <diy_efi at coulomb.eng.ohio-state.edu>
> > Subject: Water Injection for power?
> > Date: Sunday, September 08, 1996 4:31 PM
> > 
> > 
> > I just looked at the current issue of "Midnight Engineering," and saw an 
> > article that may be of interest.  The author suggested that, instead of 
> > the usual fan/radiator/et al, the cylinders be cooled by injecting water 
> > (diesel style) during the latter part of the power stroke.  The H2O would
> 
> > flash into steam, thereby changing the heat (normally exhasted) into 
> > mechanical power.
> > 
> Why bother?  The British in their pre-war experiments with water injection
> directly injected the water in a fine mist into the inlet of the mechanical
> supercharger of the Rolls Royce engine powering the spitfire.  At any 
> reasonable injection rate  engine thermal loss's went down as the per cent
> rate of water to fuel went up.  If memory serves me correctly at about 30
> percent the engines water cooling was no longer a factor.  Methyl Alcohol
> was added in a small percentage as an antifreeze - tis no such thing as a
> warm day at 30,000+ feet altitude.

> I Remember two relevant curves - holding fuel constant, power went up 
> linearly with water on a percent by percent basis.  100% fuel 10% water, 
> + 10% power etc. until a practical limit of about 50% was reached.

  So I could inject water at the intake manifold without losing power 
while maintiang the cooling effect?  Good to know, cuz I don't want to 
actually pull the engine to pieces.  Slightly unrelated question: does 
anyone know how this would affect *heated* O2 sensors?

Thanks!
                Thor Johnson
       johnsont at falcon.mercer.peachnet.edu
   http://falcon.mercer.peachnet.edu/~johnsont
                                                    
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