In which vehicle is solid fuel used?

A fuel, often too fuel called, is a chemical substance, the energy content of which is usually made usable through combustion or other forms of energy conversion for generating power or generating a drive in technical systems. Fuels are often used in means of transport (vehicle, aircraft, ship, rocket). Since they each have to be transported, substances with a high energy density are usually used.

Oxygen from the air is usually used as the oxidizer during combustion, sometimes, especially in rockets, but also a separate oxidizer such as liquefied oxygen, nitrous oxide or nitric acid.

Fuels are fed directly to machines that generate power, for example engines or gas turbines. In contrast to this is the term fuel, which indicates its use for pure heat generation. This definition of the terms is independent of the chemical composition. So is diesel one fuel, which is chemically almost unchanged under the name "Heizöl EL" as fuel is used. The water that drives the turbine of a hydropower plant is not referred to as fuel because it does not use any chemical energy content.

Types of fuels

Solid fuels

  • Nuclear fuel (uranium, plutonium) in connection with steam engines
  • Coal in connection with steam engines (coal-fired power station)
  • Solid fuels (e.g. for propulsion systems for solid rocket rockets)
  • Biomass (wood, straw ... for firing steam engines or use in wood gasifiers)
  • Coal dust can be blown into the combustion chamber using compressed air according to the diesel principle and ignites itself (coal dust explosion).

Liquid fuels

Gaseous fuels

Process for the production or extraction of fuels

Comparison of fuels

The physical comparison of the calorific values ​​(kWh per m³) shows that the advantages of certain fuels in terms of fuel consumption when stated in l per 100 km are based on their higher density and the correspondingly higher weight per liter and not on their energy content per kg:

  • Methanol: density 787 kg / m³ liquid, calorific value 6.49 kWh / kg = 5.1 kWh / l
  • Ethanol: density 789 kg / m³ liquid, calorific value 7.44 kWh / kg = 5.9 kWh / l
  • Autogas (LPG / GPL): density 540 kg / m³ liquid, calorific value 12.8 kWh / kg = 6.9 kWh / l
  • Super gasoline: density 740 kg / m³ liquid, calorific value 12.0 kWh / kg = 8.9 kWh / l
  • Vegetable oil: density 920 kg / m³ liquid, calorific value 10.0 kWh / kg = 9.2 kWh / l [1]
  • Natural gas L-gas (CNG / GNV): density 0.82 kg / m³ (standard cubic meter) gaseous, calorific value 11.3 kWh / kg = 9.3 kWh / m³
  • Gasoline-benzene mixture (Bibo): density 796 kg / m³ liquid, calorific value 11.6 kWh / kg = 9.3 kWh / l
  • Benzene: density 879 kg / m³ liquid, calorific value 11.1 kWh / kg = 9.76 kWh / l
  • Diesel: density 830 kg / m³ liquid, calorific value 11.8 kWh / kg = 9.8 kWh / l
  • Natural gas H-Gas (CNG / GNV): density 0.81 kg / m³ (standard cubic meter) gaseous, calorific value 13.0 kWh / kg = 10.5 kWh / m³

The possibility of using a fuel in an engine depends not only on the combustion properties, but also on the design of the engine and its fuel supply for the respective chemical properties of the fuel and the additives added to it. For example, valves and valve seats that have only been designed for the additives of gasoline can wear out more quickly when operated with natural gas or LPG (no admixture of additives).

In addition, a distinction must be made according to the ignition principle, i.e. whether compression ignition (diesel engine) or external ignition (gasoline engine) is used.

Alternative fuels

As alternative fuels are fuels that can replace conventional fuels made from mineral oil.

  • Natural gas (CNG) has been available in Germany since the 1990s. Millions of automobiles are already driving it in Argentina, Brazil and Italy.
  • Ethanol fuel (bio-ethanol) is obtained from sugar beet or wheat. Since 2005 it has been mixed with normal petrol in small quantities in Germany. Many automobiles already use it in Brazil, see Flexible Fuel Vehicle. Processes for the production of cellulosic ethanol from plant biomass are under development.
  • Biodiesel is made from vegetable oils esterified with methanol. The basis of the vegetable oils is, among other things, the seeds of the rapeseed plant. It is also added to mineral diesel for climate protection reasons. Since the properties of biodiesel are very similar to those of mineral diesel in many respects, diesel engines that have not been converted can also be operated with this fuel. Since biodiesel behaves like a light solvent, seals and hoses in the fuel system may be attacked if they are not resistant to biodiesel. The disadvantage is the high cost of production and the low degree of decentralization of the biodiesel plants operated in Germany. In addition, biodiesel can hold a large amount of water, which can lead to corrosion problems on the injection equipment.
  • Biogas is mainly used for stationary engines and for heating purposes in the vicinity of the generating plants.
  • BtL fuel (Biomass to Liquid) is also available under the brand name SunDiesel expelled. It is made from biomass, such as. B. won wood or straw. BtL is still in the testing phase and still has a great need for research. With him all components of the plant can be used and he has a high energy density. Conventional diesel vehicles can also drive with it. An overall energy balance for the BTL processes is not yet available.
  • Pure vegetable oils e.g. B. from camelina, rapeseed or sunflower, also called "Pöl" or natural diesel, can be used as fuel in diesel engines. In particular, the higher viscosity compared to diesel fuel means that an adaptation of the fuel and injection system is necessary for the permanent operation of diesel engines with vegetable oil. In addition to the CO2-Neutrality, the possibility of decentralized production, the high energy density, the low risk potential for people and the environment (not hazardous to water, not dangerous goods, non-toxic, high flash point).
  • Hydrogen can be obtained from renewable electricity by means of electrolysis. However, it is cheaper to obtain it by direct chemical conversion of biomass at high temperatures (steam reforming). Hydrogen can be used with internal combustion engines or fuel cells.
  • Wood gas was a common alternative in the 1940s under the pressure of acute fuel shortages. Vehicles with self-made wood gasifiers can still be found in Finland today. In the process, normal wood, often wood waste, carbonizes in the absence of air in a pressure vessel or decomposes with insufficient air combustion. The resulting flammable gases (mainly methane when there is no air, mainly carbon monoxide, hydrogen and methane when there is insufficient air decomposition) are fed to an engine after cooling and cleaning. Stationary wood gas systems are used for heating purposes and in combined heat and power systems.

Fuel price development


Price development for lead-free 95 in a European comparison (As of July 7, 2006 in euros)[2]

country SFr.
Norway 1,53 2.40
Netherlands 1,51 2.37
Belgium 1,43 2.25
Denmark 1,42 2.23
Germany 1,37 2.14
Italy 1,35 2.12
France 1,29 2.02
Luxembourg 1,18 1.85
Hungary 1,15 1.81
Austria 1,13 1.78
Switzerland 1,11 1.75
Poland 1,09 1.71
Czech Republic 1,07 1.68
Slovenia 1,04 1.63
Spain 1,03 1.61
Slovakia 1,00 1.57
Samnaun1 0,93 1.47
Canary Islands1 0,78 1.23
Ukraine 0,67 1.05
Russia 0,53 0.83

1 Duty free

Fuel prices worldwide (selection) in Euro 2006

country 1 l Super (98) in euros 1 liter of diesel in euros 1 kg CNG natural gas in euros
Argentina 1,44 1,12 0,53
Bolivia 0,50 0,38 0,17
Brazil 0,92 0,61 0,37
Chile 0,54 0,33 0,21
Germany 1,40 1,14 0,89
France 1,21 1,03 n / a
Italy 1,30 1,14 n / a
Canada 0,38 0,29 0,19
Colombia 0,50 0,25 0,21
Mexico 0,46 0,33 0,19
Netherlands 1,42 1,03 n / a
Austria 1,11 0,94 0,89
Portugal 1,28 1,00 n / a
Spain 1,06 0,90 n / a
United States 0,57 0,58 0,43
Venezuela 0,09 0,05 0,002

1 kg of natural gas corresponds to approx. 1.5 liters of super, approx. 1.3 liters of diesel

Source: (data status: March 2007), (CNG prices, data status December 2006), exchange rate from US dollars to euros on March 8, 2007

See also


  1. EE-Saarland "Pre-standard DIN 51605 - Rapeseed oil fuel"
  2. Touring Club Switzerland

Category: Biomass