WWII French car propulsion question

Despite being a question borne of watching a movie, I think this belongs here in GQ rather than Cafe Society.

I just watched {i]Is Paris Burning?*. and I noticed several civilian automobiles had what appeared to be torpedo shaped high pressure gas tanks mounted on their roofs,

Apparently it was some wartime accomodation to vagaries in fuel supplies. While I’ve read of wood burning busses in Germany, I haven’t run across this before. Anyone care to explain?

They were called gazogène. They were propelled by gases emitted from burning charcoal. It was developed by a Georges Imbert. Sorry, if they’re is not more information, everything I found through Google was in French.

They had these in the UK also. I thought they carried natural gas or something, but you’re right, it’s apparently coal gas. This guy says some busses had trailers where coal was burnt, with pipes to the bags on the roof. Trippy.

The reason they used coal gas was because that this was the type of gas in common use in the country. It wasn’t until the 70’s that natural gas ( from the North Sea and Algeria ) was used in the UK. The coal burning gasworks then all closed down.

Another model

The reason they used coal gas was because that this was the type of gas in common use in the country.

Perfectly true, but not the only reason why it used for automotive fuel. In every set-up I’ve encountered, charcoal, coal or even wood is carried along with the vehicle and partially burnt in an external generator to generate the gas in situ. The generator was either in a trailer or bolted to the front or back of the vehicle, see the pics at:

http://highforest.tripod.com/charcoal/1944.html

More links on the subject at:
http://highforest.tripod.com/woodgas/woodgas.html

And for a fairly technical description and highly cunning design for one of these things, check out:
http://www.hotel.ymex.net/~s-20222/gengas/kg_eng.html
As far as I know, fuel gas simply stored in a high pressure tank was not used, although someone may well know better…