In 1942, amid World War II’s fuel shortages, Norwegian engineers at Frydenbø began designing the Frydenbø carbide generator—a wood gas system to replace rationed gasoline. Approved by the government in August, it was quickly produced and sold through Ford dealers near Oslo, with sub-agents nationwide. Often called the “knob car” or “wood-burning car” by locals, the generator was mounted on the rear of vehicles like the 1930 Ford, using small wood pieces (“knots”) to produce combustible wood gas. This innovation allowed cars to run on local resources, powering Norway’s wartime mobility.
Wartime Necessity and Design
Gasoline rationing during the Nazi occupation forced innovation. The Frydenbø generator, a gasification unit, burned wood in an oxygen-limited chamber, producing wood gas (a mix of carbon monoxide, hydrogen, and nitrogen). After cooling and filtering, the gas fueled internal combustion engines with minimal modifications. Similar to Imbert generators mass-produced since 1931, it enabled up to 9,000 vehicles in Norway by the war’s end. The system, bulky yet effective, extended vehicle range to 100–200 km per load, a lifeline for civilians and essential services.
How It Worked
Wood knots were loaded into the generator’s firebox, ignited, and partially burned to create producer gas. The gas passed through a filtration system to remove tar and ash, then entered the carburetor. Engines required slight adjustments for the lower energy density, but output was comparable to gasoline. Mounted at the rear for balance, the generator weighed 100–200 kg, making vehicles like the Ford V8 (popular in Norway) ideal. By 1944, Finland had 43,000 “woodmobiles,” and Norway around 12,000, highlighting the technology’s success.
Legacy of Resourcefulness
The Frydenbø generator, like the SR-71’s test flights or the Pantheon’s doors, embodies wartime ingenuity. Sold via Ford in Strømmen, it powered Norway’s resilience, echoing the Jolly Roger’s strategic flags. Today, Frydenbø Group thrives in automotive and maritime industries, a nod to its innovative roots. This “knob car” era reminds us how necessity sparks creativity, turning wood into wheels amid crisis.
