mother earth news ran a lot about wood gas in the 70's and 80's overall not too impressive. 1)you need a truck with a bed to somewhat safely carry around the generator so you end up using a truck for a small cars job 2) and it still burns a lot of wood for not great power
rereading this I will retreat somewhat IMO -for transport woodgass is a horrid tech; heavy bulky generator with heavy bulky feul -but for stationary applications, especially when the waste-heat can be used for home heating or other processes it has potential.
I'd like to second Brice Moss's comment, and add that there are potentially better ways for wood to fuel an engine.
Pyrolysis can produce methanol and/or acetic acid, both of which can produce esters that are good as motor fuel. Methanol is a feedstock for biodiesel, and ethyl acetate is potentially better than ethanol in several ways, including energy density and hygroscopicity (bonding to acetate makes it easier for ethanol to give up its hold on water). Methyl acetate is also usable, but is a little more toxic.
"the qualities of these bacteria, like the heat of the sun, electricity, or the qualities of metals, are part of the storehouse of knowledge of all men. They are manifestations of the laws of nature, free to all men and reserved exclusively to none." SCOTUS, Funk Bros. Seed Co. v. Kale Inoculant Co.
i have been very, very interested in syngas recently. it seems to me that it is a very useful tool for electricity generation and for other local jobs.
if i had the resources (sustainable wood), i'd definitely hook up a syngas system on a tractor or farm truck. most farmers have a diesel tank in their trucks anyways for refilling tractors and such, right? why not replace that with a syngas system?
before i got interested in permaculture, i had a lot of time spent worrying about collapse and had anxious daydreams all the time about what i would do if XYZ happened. i had thought a subaru baja would be the perfect get away vehicle. a syngas system in the bed with racks for lashing supplies, etc. the awd and the potential to beef up the suspension with rally-grade equipment and a slide plate under the drive train would make it a pretty much unstoppable vehicle.