Dear Mother: Producer Gas Vehicles

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Dear MOTHER:

In MOTHER No. 25, C. and T. Martin asked about powering cars with gas generated from solid fuel. I have some firsthand experience with this technique and would like to share what I know.

During World War II — when I lived on a farm in Germany — liquid fuel was almost non-existent and many tractors, trucks and autos were converted to wood gas. A tank which looked like a large hot water heater was mounted on the vehicle. You prepared the system for use by filling the container with wood blocks the size of a fist and closing the lid. Then you switched on an electric or hand-cranked blower which applied suction to the bottom of the tank near the grate. Next, you stuck a burning torch through a hole into the lower part of the generator and lit a smoldering fire which was fanned by the stream of air.

To find out if the gas generated by the burning wood was good enough to run the engine, you held a torch to the exhaust of the blower. If the result was a long hot flame, you switched off the fan and turned a valve which piped the gas to the manifold (via a mixing valve that combined the fuel with air). Then you turned on the starter and the engine would catch . . . usually, anyway.

Actually, any combustible material can be turned into a gas by means of a smoldering combustion process similar to that in a burning cigarette. (Even cigarette smoke, for example, will burn if mixed with air in the right proportions.) The gas generator therefore offers an alternative method for powering an auto with pig manure . . . provided the droppings, or whatever you use, are fairly dry. The fuel has to have the right moisture content: Too wet, and it won't burn. Too dry, and it will burn too hot, turning the ashes into slag (which causes stoppage) and perhaps melting the grate too. Also, a certain amount of moisture contributes greatly to power because the water molecules are split into H 2 and 0 by the intense heat.