LPG O2 sensors

[Angus Mackinnon]

> 
> > > It appears that the liquid fuel from the tank goes to (probably via a
> > > pressure regulator) into a box that contains a standard EFI fuel system
> > > (pump/regulator etc). IE it's operation pumps the LPG around as a
> > > Liquid.
> > 
> > You don't need to "pump" LPG.  The vapor pressure should be adequate.
> > 
> 
> True, however this system is treating the LPG as a liquid fuel in the
> same sense as conventional petrol/gasoline.

 Craig, I  assume you are talking about the Australian company
 LiquidPhase ( I think) based in Adelaide that is developing a liquid
injection gas system. I can't remember the exact reasons but the LPG is
pumped at high pressure (> 100psi seems to ring a bell, though this
does seem extreme). The use of an aftermarket fuel injection computer
is necessary as the injector pulse width is radically different to that
for the OEM gasoline system I think that seperate injectors were used
for the gas but I'm not sure, I'll have to chase up the article I read
on it.

> 
> I was wondering if a standard LPG regulator would provide a constant
> pressure output, in the same manner as the fuel pressure regulator in a
> conventional gasoline EFI system. This would greatly simplify the
> installation, no pumps required.
> 


The standard LPG system uses a converter to allow the liquid to expand
to gas. The rate at which this happens is controlled by a diaphragm . So
I don't think that it works quite the way you are thinking of.


Regarding the O2 sensor, LPG systems fitted to cars after 1985 require
that the O2 sensor be connected to provide closed loop control of the
mixture to meet emission requirements for Victoria, Australia. ( I
don't know what it is like in the USA. ) OEM LPG vehicles in Australia use
LPG carbs as far as I know, I think the EFI is retained for dual fuel. 


Angus Mackinnon

angus at rdt.monash.edu.au