1980 - Volume #4, Issue #1, Page #01
[ Sample Stories From This Issue | List of All Stories In This Issue | Print this story
| Read this issue]
Tractor Generates Its Own Fuel On The Go
"Most any farmer handy in a farm shop can convert a gas or diesel tractor to wood-gas in two days or less, and for a cost of less than $500," Bohlen told FARM SHOW: "If you don't want to make up a home-built unit yourself, you could possibly buy a factory made import from Japan or Sweden for about $2,500."
Bohlen's experimental wood-gas tractor is wing tested at the Greenpeace Experimental Farm located on Denman Island, 100 miles northwest of the coast of Vancouver Island. Bohlen, director of the Experimental Farm, believes the wood-gas concept offers "great promise" for putting farmers a step closer to energy self reliance. The "stove" which he mounted on the side of the experimental wood-gas tractor is 2 1/2 ft. in dia. and 5 ft. high. It holds about 45 lbs. of fuel (wood chunks, chips or charcoal) and needs to be fed every two hours.
Bohlen believes wood-gas generators, which were popular in Europe during World War II, can be updated and refined to play a key role in beating the high cost of fuel for farm tractors, cars and trucks. In addition to producing if own fuel "on the go" for field work, a wood-gas tractor could also be used for other applications. For example, it could be used to power a generator which, in turn, could produce the farm's electricity, Bohlen points out. Once converted to wood-gas, a gas or diesel tractor (or car or truck) can be returned to normal operation on gas or diesel fuel. Or, it can be equipped to run, as a dual unit, using the wood-gas fuel system after being started on conventional gasoline or diesel fuel. Bohlen notes that his wood-gas tractor is very clean burning. There is no smoke in the exhaust and very little carbon dioxide. It gets the equivalent of 3 gal. of gasoline from each 45 lb. load of wood burned in the stove. "On a gas tractor, there is a reduction in power of about 30%," he points out. "However, this is easily overcome by increasing the tractor's compression ratio, and adjusting the carburetor to provide a 1:1 ratio of air to wood-gas," Bohlen points out.
Here are other modifications he made in rigging up his experimental wood-gas tractor: The tractor's engine was modified by installing a T-shaped pipe on the air intake pipe to the carburetor. One branch of the "T" is the wood-gas input, and the other branch feeds air to the carburetor when the tractor is operating on regular gas. "This is a hybrid gas/wood-gas conversion because we want fast starts with no cold morning hassles," Bohlen explains. "The unit has been so reliable, however, that the regular gas option really hasn't been necessary for coldmorning starting." The idler pipe of the generator leads to a particle separator, or cyclone. Fron there, gas goes to a cooler mounted in front of the tractor radiator. The cooled gas is then sent through a filter to rid it of impurities. Suction from the engine keeps gas flowing out of the generator and into the engine. The system must be kept scrupulously clean or else particle matter will find its way into the engine, causing trouble of all kinds, including premature "seizing" of the pistons. This can be avoided by examining filter components and draining down the accumulation of water in the cyclone and gas cooler.
The system's chemical process is quite simple, says Bohlen: "Combustion of wood-gas yields carbon dioxide (CO2) and water, plus some methane and hydrogen in very small amounts. The CO2 then is drawn through the combustion zone while hot and, in the process, passes through hot charcoal. The passage of the gas produces carbon monoxide (CO) and water. The CO is the produced gas that, after cleaning, powers the engine. The water breaks down into its component parts, with the hydrogen becoming a part of the fuel cycle."
Click here to download page story appeared in.
Click here to read entire issue
To read the rest of this story, download this issue below or click here to register with your account number.