Multi-fuel engine
Multi-fuel engine is a collective term for internal combustion engines that can be operated with more than one type of fuel . Multi-fuel engines go back to the beginnings of engine construction.
history
As early as 1903, the German engineer Joseph Vollmer presented the first truck of NAG , the automotive division of AEG , which was powered by a multi-fuel engine. The gasoline engine with 50 hp worked with magneto ignition and a carburetor that was designed for both gasoline and alcohol .
Since specialized fuels were difficult to obtain in the early days of automobile history, many manufacturers turned to multi-fuel engines. As the filling station network was expanded, these constructions lost their importance. Today, multi-fuel engines are particularly widespread in the military sector, where the greatest possible independence from specific fuel types is sought.
Engine variants
Multi-fuel engines are generally self-igniting reciprocating piston engines that are operated on the diesel principle . In addition, some engine versions have spark ignition , as not all fuels ignite properly without this. The large number of fuels such as gasoline , petroleum , kerosene , vegetable oil fuel , ethanol , wood gas or heavy oil lead to different constructions depending on their properties, for example cetane number , octane number and viscosity (see also combustion engine and overview of injection technology ).
Although multi-fuel engines mostly work according to the diesel principle, they differ in their design from pure diesel engines, which are only designed for diesel fuel . On the one hand, technical solutions have to be provided in order to increase the temperature of the mixture so that all fuels used ignite by themselves within the permissible ignition delay . This can be done by increasing the compression or preheating the intake air. A grid heater in turn can be achieved by charging no intercooler , exhaust gas recirculation in or electric heating intake tract reach. A spark plug or glow plug is also used in the combustion chamber to assist .
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 works without an injection device and without a carburetor.
When designing all seals, it must also be ensured that they are not attacked by the different fuels.
Well-known multi-fuel engines include:
Overview of the fuels
Both fossil and renewable fuels can be used:
- Liquid gas , also known as autogas (LPG = Liquefied Petroleum / Propane Gas, also known as Low Pressure Gas)
- Natural gas (CNG = Compressed Natural Gas or LNG = Liquefied Natural Gas)
- Gasoline fuels such as gasoline or alcohol
- Light oils such as diesel fuel and biodiesel
- Heavy oils
- Coal dust
Applications
The use of multi-fuel engines is now practically limited to military vehicles, especially tanks . One example is the Bundeswehr's Leopard 2 battle tank .
In public and private use, multi-fuel engines are used e.g. B. to supply power to remote courtyards, in block-type thermal power stations they provide electrical energy and heat.
Multi-fuel glow-head engines can be found in ancient tractors and marine diesel engines. The heavy oil two-stroke diesel engines often used on ships can also be viewed as a technical variant of the multi-fuel engines, even if they are mostly limited to heavy oil for economic reasons (low fuel costs).
See also
Individual evidence
- ^ Helmut Hütten: Motors. Technology, practice, history . Motorbuch Verlag, Stuttgart 1982, ISBN 3-87943-326-7 .
- ↑ Institute for Future Energy Systems at the University of Technology and Economics (HTW) Definition: Dust motor / turbine ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Patent DE2938694 : Six-stroke diesel and Otto dust engine.
