Multifuel

Multi-fuel engine is a collective term for internal combustion engines, which can be operated with more than one type of fuel.

History

Multi-fuel engines go back to the beginnings of engine construction. Already In 1903, the German engineer Joseph Vollmer before the first truck of the NOS ( the automotive division of AEG ), which was driven by an early multi-fuel engine. The gasoline engine with 50 hp worked with magneto ignition and a carburetor, which was designed for both gasoline and alcohol.

Since specialized fuels were not easily available in the early days of automotive history, attacked relatively many manufacturers back to multi-fuel engines. As the filling station network was expanded, lost these constructions in importance. Today, multi-fuel engines are particularly common in the military sector, where often the greatest possible independence is sought by the station network.

Engine variants

Multi-fuel engines are generally self-ignition reciprocating engines that are operated on the diesel principle. In addition, some versions have a positive ignition engine, as not all fuels properly without this light. The plurality of fuels (gasoline, kerosene, kerosene, vegetable oil, fuel, ethanol, wood gas, heavy oil ) performs a function of their properties ( cetane number, octane number, viscosity) to different structures, see the internal combustion engine and an overview of the injection.

Although multi-fuel engines are usually based on the diesel principle, they differ in their construction of clean diesel engines, which are only designed for diesel fuel. Firstly, technical solutions must be provided in order to increase the temperature of the mixture so that all fuels used ignite within the allowable ignition delay by itself. This can be done by increasing the compression or preheating the intake air. An intake air preheating in turn can be achieved by charging no intercooler, exhaust gas recirculation or electric heater in the intake tract. Supporting is also a spark plug or a glow plug used in the combustion chamber.

On the other hand, the injection pump must be connected to the lubricating oil circuit as some of the fuels used have no lubricating effect. The Lohmann engine does not need injector and without carburetor.

Finally, all the seals are designed so that they are not attacked by the fuels.

Known multi-fuel engines are:

  • Mid spherical motor
  • Elsbett engine
  • Lohmann engine
  • Hot bulb engine ( Lanz Bulldog)
  • Gas engine

Overview of the fuel

It can both fossil and renewable fuels are used:

  • LPG, also known as petroleum gas ( LPG = Liquefied Petroleum / Propane gas, even low pressure gas) known
  • Natural gas (CNG = Compressed Natural Gas or LNG = Liquefied Natural Gas)
  • Gasoline fuels such as gasoline or alcohols
  • Light oils such as diesel fuel and biodiesel
  • Heavy oils
  • Coal dust

Applications

Vehicles with multi-fuel engines are now effectively limited to military vehicles, where the greatest possible independence is sought in the fuel supply. One example is the Leopard 2 battle tank of the German Army.

In the public and private use multi-fuel engines are used for example for Supplying electricity to outlying farms, cogeneration power they supply energy and heat.

Multi-fuel -grade semi-diesel engines found in ancient tractors and marine diesel engines. The heavy fuel oil Two-stroke diesel commonly used on ships can be viewed as a technical variant of the multi-fuel engines, even if they are for economic reasons (low fuel costs ) are already mostly limited to heavy oil.

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