At 12:52 AM 7/17/2002, Timothy Crooks wrote:
>I many of the VW history books it is noted that some eary K�belwagens and VW
>staff cars were modified with charcoal burners because petrol was very
>short.  I wonder how this was done?  And in the 1940's.  I do not think it

This is done in a "gas producer" (or "gasifier" or "gazogene") in which the
charcoal is burnt with insufficient air.  The result is a gas containing
one-third carbon monoxide and two-thirds (useless) nitrogen, plus small
amounts of  unburned hydrocarbons, CO2 (undesirable) and hydrogen.  Gas
made by this process is called  "producer gas" and particularly in this
case "air gas."

A modified process probably not used with cars (my guess) involves
injecting steam along with the input air.  This results in "semi-water gas"
containing roughly one-third each of CO, H and N2, a distinct improvement
in quality (but still poisonous as heck).

Both processes lose a good deal of energy in the partial burning of the
charcoal, and the resulting gas is not something you'd burn in an auto
engine if you had other choices available.  I suspect you'd get a third or
less of normal power.  Producer gas in industrial quantities made from coke
or coal was used for operating large stationary engines, heating boilers
and other industrial uses, and by adding additional hydrocarbons also for
illumination.

There are currently efforts to build modern gas producers using biomass
such as sugarcane leaves and bagasse as fuel.

A google search on "gazogene" will turn up many references to
gazogene-fueled wartime vehicles.

david

--
David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"