[Fwd: RE: Propane/water/alcohol injection and O2 sensors]

Phil Lamovie phil at injec.com
Wed Apr 10 15:02:36 GMT 2002



Bill wrote

> Now I am confused.

> In a brief literature search, which left be a little
>  bewildered the following patterns emerged.

> 1. Vapour phase mixing uses reduces HP by 5% beacause 
> of loss of air volume

True and unavoidable

> 2. Liquid injection offers higher HP than vapour phase 
> (figures of 20% more than petrol have been quoted, 
> 60% in one case!)BUT little/no data on how the 
> injection is carried out.

There is indeed more or less power to be made depending on
where the energy for expansion is taken from. If it is all 
from the air as in the intercooler scenario you have a big 
gain. If you spray it on the inlet manifold walls then 
that's where the energy will come from. It's an air thing.

3. Propane has a RON of 112 so needs advanced timing not retarded

Timing is a function of mass fraction burned. We advance until we 
get the pressure rise at the best crank degrees.

 Ron and his mate MON (motor octane number)
are all about pre ignition and how hard you can squeeze before
you get self ignition. Think opposite to diesel.

> But it would appear that propane systems are still a bit 
> basic in 97% of cases.

99% of all propane systems use a "vaporizer" to exchange hot water
energy with the liquid LPG that's expanding. This is not just basic
it's awful. (but cheap)

> What you are saying about expansion makes sense. I need
> to do much more research.


The reason you don't see much OE with LPG injection 
is all down to the politics and economics. It cost more 
to do a better job i.e. Injection but the countries that 
have good LPG distribution are using LPG as a "poor man's
fuel". If the emission regulations get tight enough you will
see a sudden upsurge in applications.

phil
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