Trucks on a low-calorie diet
Miracles do not happen
The ideal future would look like this: throw a few logs into the car's firebox and drive hundreds of kilometers. Theoretically, this is only possible with a fantastic efficiency of 95–99%. In practice, humanity has long relied on fossil and non-renewable fuels. Nevertheless, there were times when cars were actually fueled by wood, coal, and even peat. These were attempts to switch vehicles to a low-calorie diet. The results were far from ideal, but for their time, such vehicles were quite functional.
History The development of solid-fuel vehicles began long before the advent of gas generators. In 1801, French engineer Philippe Le Bon patented a design for an engine powered by wood gas, and in 1823, British engineer Samuel Brown built one of the first practical gas engines suitable for running on wood gas. These experiments were largely laboratory experiments, but they laid the foundation for further development of the technology.
It is important to clarify here the difference between a steam engine and a gas generator engine.
Steam engine
A steam engine is a power plant in which water is heated in a boiler to steam, which is then forced under pressure into cylinders to perform mechanical work. The first full-scale steam engine on wheels was a French cart. artillery officer Nicolas-Joseph Cugnot - Fardier de Cugnot, built in 1770. Eighteen years later, James Watt created a double-acting steam engine.
A gas generator is designed differently. It's not an engine per se, but an auxiliary device that produces combustible gas through the incomplete combustion of solid fuel in a limited oxygen supply. This gas is then fed into a conventional carbureted internal combustion engine.
Fardier de Cugnot
A steam engine completely replaces an internal combustion engine, while a gas generator merely adapts an existing engine to alternative fuels. A steam engine delivers tremendous torque at low speeds, requires no traditional gearbox, and can start under load. A gas generator, by contrast, consumes up to a third of the engine's power and requires a standard transmission. A steam boiler requires 30–40 minutes to reach operating temperature, while a gas generator requires 15–20 minutes to ignite.
A steam engine consumes water, while a gas generator does not. A steam engine can run on large logs without careful fuel preparation, while a gas generator requires small logs or charcoal. Furthermore, a steam power plant is significantly heavier and significantly reduces its load-bearing capacity. Gas generators are cheaper, easier to manufacture, and can be installed on standard chassis without major modifications. However, both required constant attention: steam engines suffered from scale buildup and seal wear, while gas generators suffered from resinous deposits and clogged filters.
The full history of gas-powered vehicles begins in 1901, when French engineer Georges Imbert demonstrated the first functional gas-powered vehicle. His unit, mounted in the rear of the chassis, converted wood logs into combustible gas through incomplete combustion. The resulting mixture of carbon monoxide, hydrogen, methane, and nitrogen, with a calorific value of approximately 5 MJ/m3, was fed into the carburetor of a conventional engine.
In the 1920s, Imbert refined the design and created the compact Imbert Generator System, suitable for installation in virtually any vehicle. By 1930, more than 50 companies in 17 countries had acquired licenses for it. France became one of the first centers of mass adoption. Peugeot produced a producer gas version of the 202 model, and Panhard-Levassor created the three-axle Panhard K110 truck, capable of running on charcoal and anthracite. By 1940, there were more than 40 producer gas vehicles in France, and by 1944, amid strict gasoline rationing, their number had reached 120. Vehicles on Berliet GDR and Renault AGK chassis were particularly popular, used for urban transportation, where low speed was not a critical factor.
In the face of an oil shortage, the Germans placed particular hopes on gas generators
Germany, aware of its dependence on oil imports, pursued a targeted policy of replacing liquid fuels with producer gas as early as the 1930s. The Reichskraftwirtschaftsgesetz (Reichskraftwirtschaftsgesetz), adopted in 1930, provided incentives for owners of such vehicles and subsidies for manufacturers. As a result, by the start of World War II, more than 300 producer gas vehicles were in operation in Germany.
Körting AG developed the Körting Kraftgas Generator series of units for medium-duty trucks, while Ernst-Werke produced systems for light trucks and passenger cars. Mercedes-Benz equipped the L 3500 model with a gas generator, while Opel equipped the Blitz 3,6-36. During the war, such vehicles were used in rear and support services, saving gasoline for combat units. Projects were even developed to install gas generators on Tanks The Pz.Kpfw. IV was designed for rear-line use, but it never went into production. The Austrian company Saurer produced the Saurer 5 GF truck, which ran on coal and anthracite, and was in demand in mountainous regions.
Schulfahrzeug on the Pz.Kpfw.I Ausf.A chassis with gas generator equipment
The British took a different approach, relying on steam-powered vehicles. One of the most successful vehicles was the Sentinel S4 dump truck, produced since 1933. It ran on coal and carried up to 6 tons of cargo. The more powerful Sentinel DG6, designed for 10 tons, was used in mines and construction sites. Foden Trucks produced steam trucks, including the C-type, which was used in rural areas where gasoline remained expensive. In the 1930s, there were approximately 50 steam trucks in Britain.
The British steamboat Sentinel S4. There's no mention of gas generation here. But what thrust!
In Italy, which relied on expensive imported fuel, gas generators became widespread between 1940 and 1945. Fiat produced a version of the 626GL truck powered by wood and coal, while Lancia offered the 3Ro, which ran on coke and anthracite.
In Japan, which faced a catastrophic oil shortage after 1943, gas generators became virtually the only way to maintain road transport. Toyota created a gas generator version of the GB truck, powered by charcoal and rice husk briquettes. Nissan and Isuzu produced similar vehicles. In the Philippines, Burma, and Malaya, the Japanese army even installed field gas generators on captured Ford, Chevrolet, and Bedford chassis. These improvised solutions were unreliable, but with gasoline completely absent, there was no other option. By 1945, the total number of gas generator vehicles worldwide was estimated at over a million, making this technology one of the most widely used alternatives in the history of motor transport.
At the same time, solid-fuel steam vehicles were also developing abroad. In France, the Serpollet company was producing steam vehicles as early as the early 20th century, in Germany, Hanomag steam trucks operated in the Ruhr mines until the mid-1930s, and in the United States, there were truck versions of the Stanley Steamer and White Steamer. However, by the 1920s, steam vehicles had almost disappeared in the United States, giving way to vehicles powered by internal combustion engines, while in Great Britain, the Sentinel and Foden continued to be produced until the early 1950s.
Decisions of the Soviet Union
In the USSR, work on gas-powered vehicles began in 1928, when, at the request of NATI, engineer B.S. Stechkin began creating the first domestic unit. It could run on wood logs 10–12 cm long and 3–8 cm in diameter. The first prototype was mounted on an AMO-F-15 chassis and tested in 1930. The vehicle reached a speed of 25 km/h and consumed approximately 1,8 kg of wood per kilometer. Following the testing, it was decided to produce a production vehicle.
ZIS-13
In 1935, the Stalin Plant began producing the ZIS-13, a gas generator version of the ZIS-5. The NAMI-G13 unit, developed under the supervision of engineer L.N. Gakkel, was mounted to the right of the cab and could hold up to 100 kg of wood logs. When switching to generator gas, engine power dropped from 73 to 46 hp, and the maximum speed dropped from 60 to 40 km/h. The cruising range on a single load was approximately 40 km, after which additional loading and filter cleaning were required. Despite its shortcomings, the ZIS-13 was used in the forestry industry and on rural routes.
In 1939, it was replaced by the ZIS-21, featuring the more advanced NAMI-G21 gasifier. Thanks to an improved gasification process, power increased to 52 hp, top speed to 45 km/h, fuel consumption decreased to 1,5 kg of wood per kilometer, and range on a single load increased to 80 km. The vehicle could run not only on logs but also on charcoal, peat briquettes, and brown coal, although coal required additional gas purification. A total of approximately 8000 ZIS-21s were produced, making it one of the most widely produced generator-gas trucks in history.
In 1938, the GAZ-42, a light gas generator truck based on the GAZ-AA, was introduced. Its NAMI-G42 unit was more compact and ran on wood logs and coal. The GAZ-MM engine's power was reduced from 50 to 35 hp, and its payload capacity was reduced from 1500 to 1000 kg. Its key feature was its dual fuel system: in addition to the gas generator, the truck retained a 40-liter gas tank and could switch between the two fuel types. This made it particularly suitable for areas with unstable supply chains. A total of approximately 5000 vehicles were produced, and a small series of the GAZ-42T, a modification for peat operation, was manufactured for peat-producing regions.
There were also experimental gas generator versions of the GAZ-03-30 bus and an ambulance based on the GAZ-M1, but they never went into production. In 1944, the experimental GAZ-44 was created based on the new GAZ-51, but it never reached mass production.
The GAZ-42 could run on anthracite.
Gas generator trucks played a special role in Leningrad during the siege. According to the historian's memoirs, by 1943–1944, up to 80 percent of Leningrad's urban transportation was powered by gas generators, and these "gas generators" were used even during the most difficult days of the siege. It was thanks to these gas generator trucks that Leningrad's transportation system continued to function even during the fatal conditions of the siege. Drivers operating these trucks spent 12 hours at the wheel in the bitter cold, making five to seven trips a day across the icy Lake Ladoga to the famous Road of Life. Moreover, these gas generator drivers received the same meager rations as ordinary siege survivors, meaning they worked in conditions of hunger and cold, risking their lives to save the lives of others.
Drivers on the Road of Life became true heroes, and history has preserved the names of some of them. Soviet driver Maxim Tverdokhleb accomplished his feat just before New Year's: on December 31, 1941, for the sake of hungry Leningrad children, he performed a true New Year's miracle by transporting a whole truckload of tangerines along the Road of Life. This event demonstrates that drivers weren't simply following orders from their superiors, but imbued their work with personal meaning and compassion.
Among the drivers working on the Road of Life was Ivan Nikonovich Pozdeev, driving his GAZ-44 with a gas generator. The job of a gas generator driver was truly hellish. Drivers complained that the gas generator-powered vehicles smoked and puffed, required constant monitoring, and often broke down due to various malfunctions. Documents from that period indicate that as early as October 1942, 25 gas generator vehicles required repairs, but only 10 were completed, indicating a severe shortage of qualified repairmen and spare parts.
After the war, attempts were made to create gas-powered trucks on heavier chassis. The UralZIS-352, developed in 1949 on the UralZIS-5 timber truck, was equipped with a NAMI-G5 unit and could run on wood, charcoal, and brown coal from the Kansk-Achinsk basin. When running on generator gas, the engine produced 75 hp, compared to 95 hp on gasoline. The payload capacity was reduced from 3500 to 2500 kg, and the speed from 55 to 35 km/h.
Among the unusual projects, the ZIS-16G bus, developed in 1940 on the basis of the ZIS-16 city bus, is worth noting. Its power unit was mounted on the rear overhang of the vehicle and ran on charcoal, but due to a loss of power, the bus could not cope with inclines and was deemed unsuitable for regular service. Another experimental vehicle was the Ya-11 tractor on the YaG-6 chassis, developed in 1942 for towing heavy artillery. However, due to insufficient reliability, it also did not enter production. In the post-war period, gas generator versions of the GAZ-63 and ZIS-150 were considered, but as fuel shortages eased, these efforts were abandoned.
NAMI-012
One of the most ambitious and technically innovative Soviet projects was the NAMI-012 steam truck, whose development began in 1947 at the request of the USSR Ministry of Internal Affairs. The project was initiated by the Main Directorate of Camps, which needed transport for logging in remote areas of Siberia and the Far North, where the delivery of liquid fuel was extremely difficult. Unlike gas generators, which required small fuel and frequent cleaning, the steam truck could operate on large logs up to 50 cm long and up to 20 cm in diameter, cut directly on site.
NAMI-012 and YaAZ-200
The British Sentinel S4 steam dump truck, purchased in the USSR for testing, served as the basis, but the Soviet vehicle differed significantly from the prototype. The chassis was borrowed from the YaAZ-200 timber truck, and the layout was modified: a three-seat cabin replaced the diesel engine, followed by a medium-pressure water-tube boiler, a wood bin, a steam engine, and a water tank.
The boiler was designed for a pressure of 14 atmospheres and steam superheating to 350°C. The time it took to reach operating pressure was 30–35 minutes, which was considered good. The vertical, three-cylinder, double-acting steam engine produced 90 hp at 300 rpm and 2100 Nm of torque at low speeds—approximately five times more than the YaAZ-204 diesel engine of a similar class. It was this enormous torque that defined the NAMI-012's main advantage: the vehicle could start in any gear, confidently climb hills without shifting, and navigate off-road terrain with minimal slippage.
The NAMI-012's gearbox featured direct and downshifting gears, and the clutch design allowed for downshifting without coming to a complete stop—a highly advanced solution for its time. The gearbox function was partially replaced by a steam valve timing system: the driver could select four levels of cylinder filling with steam when driving forward and one level when driving in reverse.
The automatic fuel feed was particularly innovative: the wood, under its own weight, fell from the hoppers onto the grate as it burned, and the combustion intensity was regulated by air supply from the cabin. The fuel supply was sufficient for 60–80 km, with a fuel consumption of 120–150 kg per 100 km. The main drawback remained the weight of the unit—approximately 3500 kg, of which over 1100 kg was the boiler. This reduced the load-bearing capacity and impaired unladen handling.
The first NAMI-012 prototype, built in 1949, revealed a number of problems during testing: smoke during ignition, boiler vibration on uneven roads, and insufficient steam line seals. After further development, two improved prototypes were built—a flatbed truck and a logging tractor-trailer—which were sent to state testing in the Murmansk region in 1951.
In temperatures down to -40°C, the trucks traveled thousands of kilometers on dirt roads, clearings, and frozen rivers, transporting timber and building materials. The commission noted their excellent off-road performance when loaded, their ability to climb grades of up to 12°C, and their speed of up to 35 km/h on the highway. Acceleration to 20 km/h took 18 seconds, compared to 22 for the diesel YaAZ-204. In logging operations, transportation costs were 40% lower than those of gasoline trucks, thanks to virtually free fuel. However, heating the boiler took at least half an hour, and the weight of the powertrain limited the payload to 4 tons, compared to 6 tons for its diesel counterpart.
Based on the testing results, development of an all-wheel drive version of the NAMI-018 began. The front axle was borrowed from an experimental timber truck, a two-speed transfer case was added to the transmission, and the steam engine's power was increased to 110 hp and torque to 2500 N m. Testing showed that the NAMI-018's off-road capability was comparable to the best diesel timber trucks of its time. However, the all-wheel drive version was even more expensive to produce, and the increased weight further reduced the payload. Attempts were also made to create a version with a fuel oil furnace, but they failed to ensure stable combustion under the vibrations of a vehicle. This version remained at the prototype stage.
By 1953, work on steam-powered trucks was discontinued. The decision was driven not so much by technical shortcomings as by a changing economic situation: the development of new oil fields in Tatarstan and Bashkortostan dramatically increased liquid fuel production and made steam and gas-powered vehicles economically unviable.
The disappearance of solid-fuel vehicles from the market was due to a combination of factors. The primary factor was the sharp decline in the price of liquid fuels in the post-war period. The discovery of gigantic oil fields in Saudi Arabia, Iran, Venezuela, and the USSR led to increased production and lower prices. While global oil production was approximately 360 million tons per year in 1945, by 1960 it exceeded 1 billion tons. Gasoline ceased to be scarce and became a cheap, abundant resource, and with it, the economic basis for the development of solid-fuel vehicles disappeared.
Yet, the accumulated experience was not lost. In developing countries, gas generators were used as early as the 1960s and 1970s. In India, Pakistan, Burma, and Ceylon, converted trucks ran on charcoal and coconut coir until the 1980s. In Cuba, gas generators were used in trucks and buses until the 1970s, until the USSR established petroleum product supplies. In South Africa, such vehicles were used until the early 1970s. In the 1960s and 1970s, China produced gas generators for Dongfeng trucks that ran on charcoal and anthracite, especially in rural areas where gasoline remained scarce for a long time.
Engineering advances from the gasification era have also found application in related fields. Biomass gasification technology formed the basis for industrial plants producing syngas from wood waste. Wood pyrolysis, used in the Imbert and NAMI gasifiers, became the basis for modern biochar production technologies, which are in demand in the metallurgy and energy industries.
The Soviet experience in creating the NAMI-012 steam truck also left its mark. The idea of automatically feeding large logs into the boiler was used in the design of steam plants for river vessels and icebreakers operating in Siberian basins. The shutoff switching system was further developed in industrial steam plants, where smooth power regulation was required. The NAMI-012 design team subsequently contributed to the development of other types of automotive equipment: experience designing high-load steam engines was useful in the development of torque converters and fluid couplings for heavy trucks, and the development of boiler units was used in the creation of heating systems for buses and special vehicles.
Ultimately, despite the dead-end nature of this branch of automotive evolution, steam and gas generator power plants proved to be in demand in their time and left behind a rich technical legacy.
Information