Supercharger rotors for increased engine power output

Abstract

An apparatus and methods for a rotor pack are provided for a positive displacement supercharger that produces greater engine power output without loss of best seal between the rotors or between the rotors and an interior surface of an enclosing case. The rotors include relief zones and cupped portions at an intake airflow side of each lobe comprising the rotors. The relief zones allow additional airflow to enter the rotor pack while the cupped portions scoop additional airflow into the rotor pack during operation of the supercharger. Tapered radius portions of an enclosing case allow additional airflow to be dragged into the rotor pack. Pressure relief portions on a rotor bearing plate and angled portions on each lobe extend compression events during operation of the rotor pack. The angled portions reduce a margin of the lobes to sharpened edges without affecting the diameter of the margin.

What is claimed is: 
     
         1 . A rotor pack for a supercharger, the rotor pack comprising:
 a first rotor and a second rotor that include meshed lobes;   a shaft supporting each of the first rotor and the second rotor within an enclosing case; and   a relief zone disposed at an intake airflow side of each lobe.   
     
     
         2 . The rotor pack of  claim 1 , wherein the relief zone is configured to allow additional airflow to enter the rotor pack. 
     
     
         3 . The rotor pack of  claim 1 , wherein the relief zone comprises a curved surface that includes a line of curvature. 
     
     
         4 . The rotor pack of  claim 3 , wherein the line of curvature is tangent to a flat end face of the lobes and is tangent to a trailing surface of the lobe. 
     
     
         5 . The rotor pack of  claim 3 , wherein the relief zone extends from a termination of a radial blend prior to a compression zone to a termination of a radial seal of the lobe. 
     
     
         6 . The rotor pack of  claim 5 , wherein the compression zone comprises a valley that is disposed between adjacent pairs of lobes comprising each of the first rotor and the second rotor. 
     
     
         7 . The rotor pack of  claim 1 , further including a cupped portion comprising an intake side of each of the first rotor and the second rotor. 
     
     
         8 . The rotor pack of  claim 7 , wherein the cupped portion comprises a triangular-shaped region disposed on a leading surface of each lobe. 
     
     
         9 . The rotor pack of  claim 7 , wherein the cupped portion comprises a sharpened leading edge that transitions into flattened region of each lobe. 
     
     
         10 . The rotor pack of  claim 9 , wherein the flattened region extends to a trailing surface of each lobe. 
     
     
         11 . The rotor pack of  claim 9 , wherein the sharped leading edge and the flattened region are configured to scoop additional airflow into a rotor cavity during operation of the first rotor and the second rotor. 
     
     
         12 . The rotor pack of  claim 1 , further including an angled portion disposed on each lobe adjacent to a rotor bearing plate. 
     
     
         13 . The rotor pack of  claim 12 , wherein the angled portion is disposed between a trailing surface and a flat face of the lobe. 
     
     
         14 . The rotor pack of  claim 13 , wherein the angled portion reduces a margin of the lobe to a sharpened edge without affecting the overall diameter of the margin. 
     
     
         15 . The rotor pack of  claim 1 , further including a pressure relief portion comprising a rotor bearing plate and configured to extend a compression event during operation of the rotor pack. 
     
     
         16 . The rotor pack of  claim 15 , wherein the pressure relief portion is configured to direct air out from between the first rotor and the second rotor in an efficient manner that minimizes turbulence. 
     
     
         17 . The rotor pack of  claim 15 , wherein the pressure relief portion is configured to relieve pressure from between the first rotor and the second rotor. 
     
     
         18 . The rotor pack of  claim 15 , wherein the pressure relief portion is configured to improve airflow away from the rotors pack during the compression event. 
     
     
         19 . The rotor pack of  claim 1 , further including tapered radius portions comprising the enclosing case that are configured to allow additional airflow into between first rotor and the second rotor. 
     
     
         20 . The rotor pack of  claim 19 , wherein the tapered radius portion are configured to allow air that is dragged by the first rotor and the second rotor to enter between the first rotor and the second rotor. 
     
     
         21 . A method for a rotor pack of a supercharger, comprising:
 providing a first rotor and a second rotor that include meshed lobes;   supporting each of the first rotor and the second rotor within an enclosing case by way of a shaft;   disposing a relief zone at an intake airflow side of each lobe;   including a cupped portion at an intake side of each of the first rotor and the second rotor;   disposing an angled portion on each lobe adjacent to a rotor bearing plate; and   configuring a pressure relief portion comprising a rotor bearing plate to extend a compression event during operation of the rotor pack.