Optimized helix angle rotors for roots-style supercharger

1. An internally compressing blower comprising:

a blower housing comprising a plurality of rotor chambers and a plurality of rotors, the plurality of rotors including a twist angle and a helix angle;

wherein the rotors and the blower housing are configured to create internal fluid compression when the rotors are rotating at a first rotational speed and not to create internal fluid compression when the rotors are rotating at a second rotational speed; and

wherein the twist angle includes the angular displacement of lobes of the plurality of rotors between axial ends of the plurality of rotors, the helix angle is a function of the twist angle and a pitch diameter of the plurality of rotors, and the helix angle is at least 24 degrees.

2. The internally compressing blower of claim 1 , including a plurality of cyclically occurring internal backflow passages.

3. The internally compressing blower of claim 2 , wherein the plurality of cyclically occurring internal backflow passages are configured to permit a continuous backflow event.

4. The internally compressing blower of claim 2 , wherein the cyclically occurring internal backflow passages are configured to move linearly in a direction toward an inlet port.

5. The internally compressing blower of claim 1 , wherein the twist angle is at least 150 degrees.

6. The internally compressing blower of claim 1 , wherein the plurality of rotors are substantially identical.

7. The internally compressing blower of claim 1 , wherein the internally compressing blower is a Roots blower.

8. The internally compressing blower of claim 1 , wherein the plurality of rotors and the blower housing are configured to create the internal fluid compression without backflow slots in the blower housing.

9. A blower comprising:

a blower housing; and

a plurality of rotors disposed in the blower housing, the rotors each including a twist angle and a helix angle;

wherein the blower housing and the rotors are configured, independently from any backflow slots, to generate a plurality of cyclically occurring internal backflow passages configured to permit a continuous backflow event;

wherein the twist angle includes the angular displacement of lobes of the plurality of rotors between axial ends of the plurality of rotors, and the helix angle is a function of the twist angle and a pitch diameter of the plurality of rotors.

10. The blower of claim 9 , wherein the rotors and the blower housing are configured to create internal fluid compression when the rotors are at a first rotational speed and not to create internal fluid compression when the rotors are rotating at a second rotational speed, and the first rotational speed is greater than the second rotational speed.

11. The blower of claim 9 , wherein the blower housing includes an axial inlet port and a radial outlet port.

12. The blower of claim 9 , wherein the cyclically occurring internal backflow passages are configured to move linearly in a direction toward an inlet port.

13. The blower of claim 9 , wherein each of the plurality of rotors comprises a plurality of lobes, and

wherein each of the plurality of lobes includes a maximum ideal twist angle that does not open a leak path between inlet and outlet ports of the blower housing.

14. The blower of claim 13 , wherein the maximum ideal twist angle is at least 150 degrees.

15. The blower of claim 13 , wherein the helix angle is at least 24 degrees.