Rotary Screw-type supercharger
What is a Rotary Screw-type supercharger?
The twin-screw supercharger is quite similar to the Roots-type supercharger but has a few significant differences. The twin-screw supercharger was first patented by Heinrich Krigar in Germany in 1878 when it was developed as an air pumping compressor for industrial use. However, lack of precision engineering prevented the further development of the supercharger. With improvements in engineering precision, a Swedish engineer named Alf Lysholm was able to further developed the twin-screw supercharger in the 1930's for gas and steam turbine use. Lysholm developed the profile of the rotor lobes and testing various rotor lobe combinations and is credited with developing the modern twin-crew supercharger to the extent that the twin-screw supercharger is also referred to as the Lysholm supercharger.
The rotary screw compressor has low leakage levels and low parasitic losses vs. roots-type. The supercharger is typically driven directly from the engine's crankshaft via a belt or gear drive. Unlike the Roots type supercharger, the twin-screw exhibits internal compression which is the ability of the device to compress air within the housing as it is moved through the device instead of relying upon resistance to flow downstream of the discharge to establish an increase of pressure.
The requirement of high-precision computer-controlled manufacturing techniques makes the screw type supercharger a more expensive alternative to other forms of available forced induction. With later technology, manufacturing cost has been lowered while performance increased.
All supercharger types benefit from the use of an intercooler to reduce heat produced during pumping and compression.
A clear example of the technology applied by the twin-screw in companies like Ford, Mazda, Mercedes and Mercury Marine can also demonstrate the effectiveness of the twin screw. While some centrifugal superchargers are consistent and reliable, they typically do not produce full boost until near peak engine rpm, while positive displacement superchargers such as Roots type superchargers and twin-screw types offer more immediate boost.
From Wikipedia,
The rotary screw compressor has low leakage levels and low parasitic losses vs. roots-type. The supercharger is typically driven directly from the engine's crankshaft via a belt or gear drive. Unlike the Roots type supercharger, the twin-screw exhibits internal compression which is the ability of the device to compress air within the housing as it is moved through the device instead of relying upon resistance to flow downstream of the discharge to establish an increase of pressure.
The requirement of high-precision computer-controlled manufacturing techniques makes the screw type supercharger a more expensive alternative to other forms of available forced induction. With later technology, manufacturing cost has been lowered while performance increased.
All supercharger types benefit from the use of an intercooler to reduce heat produced during pumping and compression.
A clear example of the technology applied by the twin-screw in companies like Ford, Mazda, Mercedes and Mercury Marine can also demonstrate the effectiveness of the twin screw. While some centrifugal superchargers are consistent and reliable, they typically do not produce full boost until near peak engine rpm, while positive displacement superchargers such as Roots type superchargers and twin-screw types offer more immediate boost.
From Wikipedia,
