By Rob Arndt
In WWII, Europe was in a real fuel shortage. Oil imports were largely blocked, and what oil was available was used for aviation and tank fuel. Germany had a lot of coal, but no oil deposits. To make up for their huge lack of oil, German ingenuity turned to gasification of coal to make synthetic fuel. To run cars without using their precious oil, the German government and many European civilians tried a method of running a car by burning wood, and it apparently worked! Ford, GM, and other car manufacturers made kits, and many cars were converted to run on wood, either using a mass produced conversion kit, or a homemade version. A car using a factory built kit would run for 100,000 miles fairly problem free.
Holzbrenner “Wood burning” Volkswagen car from 1942
Holzbrenner “Wood-burning” Volkswagen Kübelwagen during WW2
The way this worked was that wood was heated until it began to break down chemically. When wood burns in a normal fire, the wood decomposes chemically due to the heat, and some of the gasses produced by the wood are flammable, and they burn as they are released. That is the flame that you see.
With the WWII era wood burning cars, however, wood was heated to a temperature hot enough to decompose the wood, but the gas was not allowed to burn. It was stored in a chamber, and injected into the cylinders of a regular internal combustion car. Some of the German made wood-burning cars were the VW Kdf Wagen (postwar Beetle), and the German Army Kübelwagen.
GERMAN/ALLIED BATTLEFIELD SYNTHETIC FUEL USAGE
During WWII, it was not unusual for some German tanks to be towed to a combat staging area. Once at the battlefront, the tanks would then be converted to burn synthetic fuel in battle. The tide of war had turned against Germany when the synthetic fuel plants were bombed and fuel production stopped. So the SS had developed a series of wood-burning electrical generators, vehicle engine conversion kits, and armored vehicle conversion kits. They were called “Holzbrenners” (Wood burners) and were made primarily by Porsche.
Cut-away illustration of the US Sherman tank
possibly with a synthetic fuel conversion kit
In 1944, US Army General George Patton was speeding across Germany with the objective of being the first Allied force to reach Berlin. His forces outpaced his supply lines and his progress stopped. Patton ordered that synthetic fuel be drained from captured or abandoned German vehicles and some of Patton's Sherman tanks and personnel carries were converted to run on synthetic fuel.
STRANGE VEHICLES OF PRE-WAR GERMANY
THE THIRD REICH