If you place normal wood, or even charred wood as should be plentiful in the Aftertime, inside an air-tight container that includes one outlet and then heat the container very hot, as putting it in a bed of coals, the wood inside will be converted to charcoal. During this process and after the water vapor in the wood is driven off (and out the outlet), many hydrocarbon gases including hydrogen, methane, and then propane and butane will also be driven out the outlet. Should this outlet be connected to something like a propane carburetor (used by many farmers for the last 30 years), the gas produced by heating wood in the absence of oxygen will easily run the engine.
The carburetor replacements can be easily obtained and are much simpler than a gasoline carburetor. With such a setup one could easily run a good size generator with all the charred wood laying around after the firestorms, or dead trees because of the lack of sufficient sunlight. Also, you end up with plenty of charcoal that can be used for cooking, heating, and firing the wood gas maker. Definitely something to follow up.
Offered by Ron.
Woodgas information is available from many web sites: http://www2.whidbey.net/lighthook/woodgas.htm