CNG/LNG

[robert dingli]

> 
> natural gas is a great fuel for  standby generators 
> 

While on the topic of CNG/LPG...

There is a fleet of port injected CNG taxis running around in Brisbane, 
Australia as well as some in New Zealand.  For our single fuel application, 
the compression ratio was raised from about 9:1 to well over 15:1, and the 
resulting peak efficiency increased from about 30% to over 40%.  Natural gas 
in Melbourne is relatively consistent (but not available in CNG form) with 
a RON of 140-142.  In Brisbane and NZ the methane ratio can be as low as 90% 
lowering the RON to about 130.

To test various methane / propane ratios, we recently installed a second set
of gas injectors with an adjustable pulsewidth proportional to the base 
injector pulse from the Ford EECV ECU.  Could this be the ultimate dual fuel
combination?

The project was set back a little last week when the dyno drive shaft flex
coupling decided to let go and hurl itself through the bell housing and
steel safety cover, across the lab, through a window and into the car park
onto an unoccupied Nissan.  Luckily no one was hurt, but the mechanical
casaulties include the drive shaft, engine crankshaft, dyno shaft,
bell housing (now lots of little pieces of aluminium) and safety cover.

LPG in Australia can have as much as 50% butane which lowers the octane rating
to just under 100.  Unfortunately this is little better than the leaded fuel
that about half the cars on our roads still use.

rambling on...
Robert

-- 
    Robert Dingli   r.dingli at ee.mu.oz.au
Power and Control Systems    (+613) 9344 7966
Thermodynamics Research Labs (+613) 9344 7712
     University of Melbourne, AUSTRALIA 
**  he who dies with the most toys, wins  **