Patent ID: 8176901

Claim:
A supercharger for boosting intake manifold pressure in an internal combustion engine and producing electrical energy, said supercharger comprising: an input shaft; an electric machine including a stator and a rotor; a compressor including an impeller; a planetary transmission coupling the input shaft, the rotor of the electric machine, and the impeller of the compressor, such that the input shaft can drive both the impeller and the rotor, or the rotor and input shaft can drive the impeller; wherein the planetary transmission includes an outer ring operatively coupled to the input shaft, a sun member operatively coupled to the impeller, planetary clusters located between the outer ring and sun member, and a carrier operatively coupled to the planet clusters and the rotor; wherein said planetary clusters each comprise an inner roller and an outer roller in frictional engagement with each other, said inner roller further in frictional engagement with said sun member, and said outer roller further in frictional engagement with said outer ring; wherein a base speed ratio (K) of the planetary transmission equals φ 1 φ 2 K 0 , wherein, φ 1 is the ratio of the outer diameter of the large cylindrical surface to the small cylindrical surface of the inner planet roller; φ 2 is the ratio of the outer diameter of large cylindrical surface to the small cylindrical surface of the outer planet roller; and K 0 is the ratio of the diameter of the inner cylindrical surface of the outer ring to the diameter of the outer cylindrical surface of sun shaft.