Ein Beitrag zur Optimierung des SCREW-Konzeptes
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Date
2006-02-15T13:29:43Z
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Abstract
During the last years the use of mechanical superchargers has gained increasing interest in a bid to combine attractive emission- and fuel consumption values with dynamic driving performance.
Based on an analysis of available supercharging systems the development potential of twin screw superchargers is assessed.
A concept using inlet slide valves is developed which allows at the same time to control the mass flow delivered by the supercharger and achieve an expansion of the transported charge under part load conditions when the delivered pressure is lower than ambient pressure, achieving a reduction in necessary shaft power or even the delivery of shaft power. To distinguish it from conventional superchargers the new device is called 'SCREW' - Screw type machine with Compressor Respectively Expander Working mode.
The effect of several design parameters on the SCREW's performance is evaluated by extensive simulation calculations, showing that a suitable design varies considerable from conventional supercharger designs and that a significant amount of further research, especially covering the development of rotor profiles suited for this specific task, is still needed to fully utilize the concept's potential.
As a proof of concept prototype SCREWs, based on a conventional twin screw supercharger, have been built and tested. The results obtained made clear the general suitability of the concept but also underlined the shortcomings of the prototype as they had already been predicted by the simulations.
The SCREW concept is suitable to control the mass flow delivered by a supercharger in a considerable range and increase the efficiency under part load conditions significantly.
To fully exploit the concept's potential a significant amount of basic optimization and a completely new design, establishing the SCREW as a category of it's own instead of just a modified supercharger, is needed.
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Schraubenlader, Steuerung, Verdichtung, Expansion, SCREW, Aufladung, Verbrennungsmotor