[Diy_efi] LPG vapor injection with gasoline injectors: calculatingfuel requirements

[Phil Lamovie]

Hi John,

Without specifying the pressure and temperature of the activity
it is impossible to calculate the equivalence in litres of flow per
minute.

You don't say how you intend to produce the vapour. If you are using
a converter with an internal regulator or some other form of pressure
control that will answer some of your question. The temperature of the
vapour will be more difficult to determine.

That said you also need to determine the propane/butane mix so that
you can correct for energy per unit volume.

As a theoretical exercise it's doable but if  you want is to use a petrol
map and a calculator to determine the "corrected" ms pulse width for
LPG you are going to be disappointed. There are many variables such
as injector opening time vs pressure that you are not going to have
data for without doing the tests yourself.

The fastest way to get an answer is to run the engine on an engine dyno
and use a 4 gas and an ignition scope to verify the results. This map will
be empirically derived and thus have all the "corrections" built in.

If some one on the list has any data on the "Boemo" vapour injectors
used on the 6 cylinder 4.0 litre Ford in Australia  that may be a big help.

HTH

Phil