Gasoline was rationed during WWII, so there was a need for running cars, trucks and tractors on local fuel, wood chips. This was done in a wood gasifier, a device that generated a low BTU fuel by partially burning the wood in an oxygen poor atmosphere. The generated gas consisted of hydrogen, carbon monoxide and of course nitrogen.
Wood gasifiers were popular in Germany, Switzerland, Austria, France and Scandinavia. There were many different designs, but the most popular design was the Imbert gasifier.
The gasifiers worked sufficiently to keep the cars moving but there were many issues with them, so that most gasifiers were removed after the war.
Only gasoline engines could be modified for gasifier use. Ignition timing had to be retarded, otherwise the engines were unchanged. Power output was a bit more than half of the gasoline rated power.
The main issue with the gasifiers was tar in the generator gas that tended to build-up in the intake manifold and on valves etc. but also inside the gasifier.
The gasifiers needed a long time to get started and reach sufficient temperature to generate a tar free gas.
Google IMBERT GASIFIER and you will find lots of pictures and diagrams etc.
Many attempts have been made to use modern high temperature gasifiers to power stationary engines with various success. Good results were achieved with large fluidized bed gasifiers.
Your (Click &Clack) hypothesis that they must have been making alcohol is a bit off base in that alcohol is produced from wood by fermentation. However, as many have already mentioned, wood can be partially destructed by heat in a chemically reducing atmosphere (low oxygen), producing hydrocarbon gases. The product composition depends on the conditions in the primary combustor. This concept attracted attention of the DOE a few years ago to investigate using these gases to even fire a gas turbine as part of a bio-fuel power plant. I didn’t hear if it was ever funded.
I must be nearly as old as Hans (and therefore only slightly older than Click & Clack!) and I remember people talking about these vehicles. Many Paris taxis employed similar technology for some years after the end of the War.
This was a hot topic back in the early 80’s in Mother Earth News. They converted a chevy pick-up to run on woodsmoke (installing two units in the truck bed) and drove across the country to prove it was possible. (No word on how many times they were stopped for the cloud of smoke coming from the truck!) They also converterd a Pontiac Tempest motor to power a generator and made a complete power station, producing electricity, compressed air from the crank pulley, and hot water from the cooling system. It was all mounted on a skid and was portable.
Of course you can run a car on wood. You can run an internal combustion engine on practically anything whose gas mixture will burn at a high enough flame rate. In the German truck’s case they had a wood gasifier unit attached. See the enclosed Wikipedia link for a very detailed explanation and history.
In days gone by, afore pipelines brought natural gas or propane or butane or some mixture thereof, to Mom’s stove; the “gas works” smoldered wood or coal in a paucity of air so as to produce fuel of highly variable BTU value. One of the byproducts was sooty black water, with maybe a scent of ammonia; this had to be pumped out of the distribution lines, which became plugged with the stuff.
If you lived in fuel-starved Germany or Japan, you could modify your car with a charcoal burner and limp your way through the war. I can remember a science teacher calling it “destructive distillation”.
Re. your non-cooling fan: How well was it expected to work in the nonexistent air?
Isn’t one of you an MIT guy? Anyway Hans is talking about gasification, a process that turns solids into gas, commonly used with biomass, such as wood chips. The process was widely used in Germany since oil was rapidly being used up by the war machine and funds were running out. When you get close (not too close) and carefully look at a piece of burning wood, you will see that gases come out of the wood and burn. These gases are mostly carbon monoxide, which is combustible. There may also be some hydrogen which always helps to light something up. Your listeners may also be interested to know that by weight, wood has a higher energy content that gasoline or oil. Wood has a much lower density than gas, so more volume is required, hence the two 55 gal drums in the back of the Opel Blitz Hans was talking about. Release of the gases is slow but steady, so you don’t have a lot of “burst” energy for quick acceleration or going up a hill in a high gear and it probably took quite sometime to get the temperature high enough to get a sufficient amount of gas to run the engine - not the perfect getaway car. The Russians must have had something even less effective. Anyhow, it works and a lot of cars and tractors were powered that way. The process has recently had a renaissance in Europe for large stationary generators with lots of R&D being put into it, the key is to produce a minimum amount of creosote and soot and have a minimum amount of ashes left over.
During World War 2 it was fairly common in Europe to convert gazoline engines to run on CO+ H2 resulting from the action of spraying water on burning coal or woodchips. Google " gazogene" and you will see articles about the subject and many pictures of converted cars and their attached appendices. Articles are in french but you get the idea.
The gas-generator setup was very common in at least the Scandinavian countries during WW-II, due to severe gas rationing. My father has told me a lot of stories about these generators, where you burn wood (chopped to kindle size pieces) with oxygen starvation. This would create carbon monoxide, hydrogen, methane (and carbon dioxide, soot, acids…). The gas was then scrubbed via filters, water baths, cooled and fed into the engine (gasoline engines). They had the main burner “tank” on a large bracket on the rear, and you had to feed it with the wood, an often precarious and dangerous task: several eyebrows were lost when the burner would flame up suddenly during a refill and a fresh inflow of air from the filler hole. Roof racks carried sacks of kindle wood for refilling during the day. At first, these generators were crude, and unfiltered gas “ate” the engines, due to all the byproducts that were fed in with the gas (acid, soot particles, etc.), but eventually became quite efficient and “clean”. One of the main draw backs were that you had to stoke and fire the generator before you could drive… another was that you were piping around carbon monoxide, which lead to quite a few poisonings due to leaks in the systems.
Do a Google search on “gasogenes” for the answer. First heard about this in the great CD by radio voice Robert J. Lurtsema, “The Man Who Planted Trees.”
Yes, there were about a half million production vehicles that ran on the wood gasification process. It was an alternative since fossil fuel was rationed during the war. I’ll have to check with my father whether he knew of any. He was 12 years old at the end of the war and evacuating his family from the approaching Russian Front in Silesia.
When I was in Chemistry in High School, my text book showed a picture of car that burned wood, not just wood chips or saw dust, to produce CO gas. The CO gas was produced by restricting the oxygen to the fire which resulted in incomplete combustion of the wood to produce the CO gas. This in turn was fed to the engine for combustion to power the car. If I remember correctly the text eluded to the fact that through out Europe, it was not uncommon to have cars that burned wood to produce CO gas that was burned in the internal combustion engine.
Google wood gas generator. They are a fairly widespread and well understood device, especially among folks who prepare for surviving without the benefit of most of our consumer economy
This is so cool. In my high-school chemistry class, we pyrolyzed wood slivers in a sealed test tube and then separated the mixture of gases that came out into two parts: 1) wood alcohol (methanol) and probably some other hydrocarbons that condensed on the cold condenser coil and 2) a mixture of light gases (including hydrogen gas and carbon monoxide) that didn’t condense. Both parts of the gaseous output burned really well, and so did the remnants in the test tube (charcoal, tar, etc.). Sounds like wood gas is the whole mix of hydrocarbons that comes out of the pyrolysis chamber. I wouldn’t be surprised if the enterprising Nords that were running these vehicles used the tar to treat their wooden cross-country skis, and then used the charcoal for fuel, digestive aids, etc.
Another thing we learned about wood alcohol is that it’s not the kind that you can drink–it’s the kind that makes people blind (or dead) if they drink it in some kind of stupid, cheap hooch.
I’m seconding the following comments that were made earlier here:
DennisAtwell 3:59PM: I remember in high school chemistry class we would distill wood in a test tube and collect the gas in a upside down flask, light a match and the gas would shoot out a blue flame. My teacher at the time said it was hydrogen gas.