to: fanglers@xephic.dynip.com
subject: alternative fuels II

 Now for another dose of retro-tech - the Packard Fuelizer.

 Back in the 1920s and 1930s "gasoline" was a rather vague term.  It 
was basically anything reasonably liquid that couldn't be sold as 
Diesel fuel.  Primitive gasolines ran around 60 octane, but even that 
wasn't dependable - as there was nothing in the way of quality 
control, it could by anything from straight light-end distillates to 
fuel oil dosed with butane.

 If you were rich enough to buy a luxury car during the Depression 
you certainly didn't want to have to dick around with manual mixture 
controls to keep the thing from pinging.  Most companies just hoped 
their potential buyers would somehow find good fuel when they needed 
it, or reduced compression and hoped for the best.

 Packard did an end-run around the problem.  They used a device 
called a "Fuelizer."  It sat upstream of the carburetor and burned 
about 3% of the total of the fuel used by the engine.  It was 
basically just a little heater, like the oil or kerosene heater you 
might have to warm your house, using intake air flow instead of a 
blower.

 The Fuelizer added heat to the intake charge.  Lots of heat.  Enough 
heat to completely vaporize whatever fuel the poor carburetor was 
attempting to carburet.  This now became "dry" fuel, just like you 
were running propane or CNG.  You got all the advantages of a gaseous 
fuel - almost no cylinder-to-cylinder mixture variation, freedom to 
run your manifolding any way you wanted, no fuel puddling, no 
lean/rich problems in the cylinder, glass-smooth idle, and so forth.

 The penalty was loss of volumetric efficiency.  Preheating the 
intake air to over 300F meant you lost power at wide open throttle.  
But Packard owners seldom used WOT, and at part throttle VE is 
essentially meaningless.  Packard could have run some sort of air 
bypass valve to cut the Fuelizer out of the circuit at WOT, but they 
took the simpler route of just building a honkin' big engine that 
made enough power from sheer displacement.  A big lazy engine was 
also more reliable and longer-lasting than a small, more highly 
loaded engine.

 The Fuelizer produced more than just heat.  Remember about 3% of the 
fuel went through it?  That wasn't just lost to heat - most of it was 
only partially burned.  Since the combustion cycle was high in excess 
air, full burning only occurred in the vicinity of the fuel nozzle.  
A Diesel engine will burn a full fuel charge with excess air, but 
only because the amount of air is limited, and hot.  The Fuelizer 
used a moving air stream, and the constant supply of cold air tended 
to put the fire out not far from the nozzle.  The result was a soup 
of partially burned hydrocarbons, CO, and other stuff - gaseous fuel 
just waiting for the proper conditions to complete its combustion.  
Glassman covers some of the chemical reactions.

 The only problem with using the Fuelizer as a gaseous fuel producer 
(as opposed to simply vaporizing the liquid gasoline) was that you 
were limited by a fixed pilot nozzle, which was sized for idling, and 
controlling the combustion of more than that would have been a 
dauntingly complex task for a simple mechanical device.

 The Fuelizer was a neat trick, almost completely forgotten nowadays.
It would work well even on a port injected vehicle; the principles 
are the same.  Modern closed-loop engine management could even let 
you turn it on and off as desired.  But a port-injected engine with a 
decent combustion chamber does well enough for the benefits of a 
Fuelizer to be small, and addition of EGR does almost the same thing.

 Now for Part III...