World War II has always fascinated me. I spend a great deal of time reading and researching a wide array of books, articles and Internet sites about this period. To the conquered peoples of Europe and Asia, it must certainly must have seemed like the end of the world as they knew it.
One of the most fascinating aspects of my studies is discovering how individuals and groups in Axis-held countries survived behind enemy lines. Valuable lessons can be gleaned by looking at the tactics and techniques of underground and partisan groups in France, the Philippines, Yugoslavia, China, Norway, Belgium and many other invaded lands.
Recently, I read a book written by Lt. Colonel Will Irwin, US Army, retired. His book The Jedburghs: The Secret History of the Allied Special Forces, France 1944. Irwin’s research is excellent; it is a riveting chronicle of secret teams that were dropped deep into Nazi occupied France. Working with local partisans known as “maquis”, the teams conducted a roaming guerrilla war against German forces.
The book revealed that French resistance forces had little or no access to gasoline during this period. The Germans needed every gallon for their own military needs, so many French improvised a technology that — in today’s übermodern high-tech society — has long overlooked. This technology, gasogene-powered internal combustion engines, became a popular method of fueling cars, trucks, and even buses during late World War II.
Simply defined, standard gasoline-fueled vehicle engines were converted with a wood- or charcoal-burning unit. The unit did not generate steam for power, but instead it created a combustible gas to run the engine. Such knowledge had been around since the late 1800s.
The gasogene device is known as a wood gas generator or gasifier by engineers. This gasification process has all but disappeared in vehicle propulsion in the 21st Century. Gasogene devices create a mixture of nitrogen, hydrogen, methane, carbon monoxide and other, combustible gases. When these are cooled and filtered they can be introduced into an internal combustion engine as an efficient fuel.
In a TEOTWAWKI environment, one quickly realizes that wood, charcoal and other natural items (even coconut husks) would be plentiful and easily acquired. Having a gasogene powered car, tractor or generator would be a huge advantage in surviving a post-apocalyptic world.
In a FEMA document on powering vehicles through gasification it was noted that “a catastrophic event could disrupt the supply of petroleum in this country so severely that this wood gas generation might be critical in meeting the energy needs of some essential economic activities, such as the production and distribution of food. In occupied Denmark during World War II, 95% of all mobile farm machinery, tractors, trucks, stationary engines, and fishing and ferry boats were powered by wood gas generator units. Even in neutral Sweden, 40% of all motor traffic operated on gas derived from wood or charcoal. All over Europe, Asia, and Australia, millions of gas generators were in operation between 1940 and 1946.”
HOW A GASOGENE UNIT WORKS
Internal combustion engines use gasoline. What many do not realize is that the liquid that we know as gasoline is turned into a vapor and burned as a gas. The technology under the hood converts the liquid form into the gas form. The vapor is injected into the engine and is explosively burned (combustion). The same is true for wood gas. Burning wood in a controlled gasifier creates a combustible vapor that will fire in the engine.
The gasogene creates a chemical process where the superheated vapors evolve into gases that the engine then burns. This is also known as a stratified, downdraft gasifier as the vapors go through four zones within the device and into the engine.
The first zone is at the highest point of the machine. Because the vapors are drawn down and into the second zone (the downdraft), the first zone is a 20 to 30 gallon metal container positioned atop the second zone, a smaller 10 to 15 gallon container.
The first container might be a small metal trash can or other type of metal box than can hold wood fuel. This upper container draws in air to aid in the combustion of the wood. A fire box connects the upper container with the lower metal container. The fire box is surrounded by open air in the lower container and a metal grate or screen is at the bottom of the fire box. Burnt wood char and ash fall from this grate into the bottom of the second container. This container has to be cleaned of all spent ash to keep the process efficient. This first container stacked above the second container (zones one and two) are the gasification segment.
From the second container a pipe runs to a third container, known as the filter unit. This enclosed container is filled with clean wood chips that act as filter medium to draw off particulates that are moving with the hot vapors in the smoke. The wood chips draw off these contaminates and a clean stream of hot vapors moves through to the final process. A blower is located above the third container to maintain air flow.
From the filter unit a longer pipe takes the vapors downstream to the engine manifold. An air intake valve pulls additional cooler outdoor air to “sweeten” the combustible gases just before entering the engine. A modifier connection attaches the gasifier pipe to the engine. A throttle valve is also mounted just before the pipe enters the engine so the flow of fuel can be controlled and help regulate vehicle speed.
Described by a layman, imagine a small metal garbage can mounted above a metal canister about the size of a five-gallon paint bucket. A short pipe connects to a third canister (also the size of a five-gallon bucket. A longer pipe, with throttle and air valve, connects to the engine manifold.
Hundreds of thousands of gasogene engines built during World War II demonstrated that innovation in use of cans, buckets and piping had little or no effect on performance. Clever mechanics used all types of scavenged and jury-rigged components.
Three things are critical to overall success and performance of the gasogene:
A. The most critical element is that the fire tube’s (running into the manifold) inside diameter and length must be carefully matched to the rated horsepower of the engine.
B. The gas generator units and all piping must be totally airtight at all times.
C. Friction must be eliminated in all air and gas passages. This is done by avoiding
sharp bends in the pipe and by employing pipe sizes which are not too small.
SKILLS NEEDED TO CONSTRUCT THE GASOGENE MACHINE
One primary skill will be creating metal connections. Cutting metal using snips is important. Bending and brazing pipe is about the most difficult of the work. It is much a combination of plumbing skills and metalworking — but it is well within the skill set of most people who are moderately familiar with tools.
Having someone with plumbing skills assist makes construction of the device much easier, but not essential. Many in World War II constructed these fuel generators with basic hand tools, components found in junk yards and assembled in extreme conditions.
OPERATIONAL AND SAFETY CONSIDERATIONS
The Gasogene unit burns wood and this means that frequent cleaning of the wood container and fire box. Ash and char will fill the lower container under the fire box very quickly. Starting the wood fuel will take some practice. Depending upon the engine itself, most units will be able to power an average sized automobile about 15 to 20 miles at regular road speeds. Shutting down the unit requires a cooling down period.
There are safety considerations that require attention. The gases produced from the unit are toxic and attention must be paid to ventilation. Enclosed cars, garages and such must be adequately vented to prevent dangerous build up of toxic gases. However, the same could be said for traditional gas fueled engines.
Having a container filled with burning wood on a moving vehicle is always a major consideration. Under normal operating conditions, this is not much of an issue. But, in the event of an accident it is very important to remember that fire risks are increased.
TAKING THE NEXT STEP
If gasogene is of interest to your future plans for self-sufficiency, it is important to be proactive now. The good news is there are plenty of resources to give you the exact plans and specifications needed to create an efficient operating gasogene engine. Kits are available to accelerate the build, but are absolutely unnecessary.
CONSTRUCTION OF A SIMPLIFIED WOOD GAS GENERATOR
for Fueling Internal Combustion Engines in a Petroleum Emergency
The absolute best reference was published by FEMA. It not only covers all of the conceptual aspects of a gasogene-powered engine as well as a complete set of technical plans with parts list. It is a single-source document that is free and available online as a PDF document. This should be a part of any document package being assembled for future times.
WOOD GAS AS ENGINE FUEL
Food and Agriculture Organization of the United Nations
FAO Forestry Paper 72
This UN document contains 139 pages of technical charts and graphs, scientific analysis and economic data on the potential and reality of wood gas fuels. It is free as an online PDF. Interesting for those seeking greater rationale on why wood gas can be an efficient alternative to petroleum in an emergency.
‘Coast to Coast on Homemade Fuel,’ Mother Earth News (#73) pp, 178-179. Jan/Feb 1982.
‘Wood Gas Update,’ Mother Earth News (#71) pp. 164-165. Sep/Oct 1981.
‘Mother’s Woodburning Truck,’ Mother Earth News (#69) pp. 126-129. May/Jun 1981
Some Useful Web Sites