| Popis: |
Today, it is possible to operate modern diesel engines on rapeseed oil methylester (RME, biodiesel), fossil diesel fuel (DF), or their blends, without violation of the actually valid exhaust limits. In the future, the engine must be adapted to the fuel in order to fulfil sharper exhaust gas regulations. This adaptation is possible without mechanical measures; the modern electronic engine management unit (EMU) can be used to achieve this. However: in order to switch to the adequate engine management (like amount of injected fuel as well as time and course of the injection), the EMU needs the information which fuel (or blend) is actually used. Sensor concepts which are able to provide this information have been studied in some depth in an actual research project. The real part of the dielectric number ( a') turned out to be an excellent indicator. In fact, a' of biodiesel is more than 50 % higher than a' of DF. The experiments that will be presented were carried out on a broad basis (fuel composition, temperature variation, fuels from different manufacturers, summer and winter qualities, aging, water content, typical contaminations; as well as different sensors operating in frequency domain and time domain). Results from the use of the prototype in a real application (AUDI A4 passenger car) will be reported, too. |
