Airfoil-based air turbine
View Patent ↗A compact air turbine configured to convert some of the energy from a stream of passing air into electrical energy. The turbine is placed on a moving vehicle in a location where drag is occurring and may in fact be placed in a location where additional drag is desirable. The preferred embodiments incorporate a movable inlet ramp or door to aid in self-starting and increase efficiency.
1. A turbine for extracting energy from air flow moving over a drag-inducing fairing of a moving vehicle, comprising:
(a) a housing;
(b) a rotor mounted within said housing, said rotor having an outer perimeter and an axis of rotation;
(c) a plurality of airfoils attached to said rotor, wherein each airfoil of said plurality of airfoils,
(i) has a chord line running from said outer perimeter to said axis of rotation,
(ii) has a first side that is flat and parallel to said chord line,
(iii) has a second side that is convex, with said convex second side protruding outward in a direction of desired motion for said airfoil;
(d) an inlet ramp configured to bend air flow coming into said turbine so that a majority of said air flow is directed toward airfoils moving away from said inlet ramp;
(e) an electrical generator attached to said rotor; and
(f) said inlet ramp being configured to pivot in order to create a variable ramp angle, with said ramp angle increasing with an increasing speed of said rotor and said ramp angle decreasing with a decreasing speed of said rotor.
2. The turbine for extracting energy from air flow as recited in claim 1 , further comprising an actuator for setting a desired ramp angle of said inlet ramp.
3. The turbine for extracting energy from air flow as recited in claim 1 , further comprising:
(a) an inlet for said turbine on a forward-facing portion of said vehicle;
(b) an outlet for said turbine on a lateral-facing side of said vehicle; and
(c) an outlet duct configured to direct air exiting said rotor to said outlet on said lateral-facing side of said vehicle.
4. The turbine for extracting energy from air flow as recited in claim 1 , further comprising an inlet door configured to selectively admit said air flow to said rotor.
5. The turbine for extracting energy from air flow as recited in claim 4 , wherein said inlet door is smoothly contoured into said fairing.
6. The turbine for extracting energy from air flow as recited in claim 4 , wherein said inlet door acts as said variable inlet ramp.
7. The turbine for extracting energy from air flow as recited in claim 1 , wherein said fairing is part of a wind deflector on the cab of a truck.
8. The turbine for extracting energy from air flow as recited in claim 1 , wherein said fairing is part of a hood on a car.
9. The turbine for extracting energy from air flow as recited in claim 1 , wherein air flow exiting said turbine is directed to an outlet in said vehicle that is remote from said turbine.
10. A turbine for extracting energy from air flow moving over a moving vehicle, comprising:
(a) a housing having an inlet, with said inlet being positioned to receive a portion of said air flow;
(b) a rotor mounted within said housing and configured to receive flow from said inlet, said rotor having an outer perimeter and an axis of rotation;
(c) a plurality of airfoils attached to said rotor, wherein each airfoil of said plurality of airfoils,
(i) has a chord line running from said outer perimeter to said axis of rotation,
(ii) has a first side that is flat and parallel to said chord line,
(iii) has a second side that is convex, with said convex second side protruding outward in a direction of desired motion for said airfoil;
(d) an inlet ramp configured to bend air flow coming through said inlet into said turbine so that a majority of said air flow is directed toward airfoils moving away from said inlet ramp;
(e) an electrical generator attached to said rotor; and
(f) said inlet ramp being configured to pivot in order to create a variable ramp angle, with said ramp angle increasing with an increasing speed of said rotor and said ramp angle decreasing with a decreasing speed of said rotor.
11. The turbine for extracting energy from air flow as recited in claim 10 , further comprising an actuator for setting a desired ramp angle of said inlet ramp.
12. The turbine for extracting energy from air flow as recited in claim 10 , further comprising:
(a) an inlet for said turbine on a forward-facing portion of said vehicle;
(b) an outlet for said turbine on a lateral-facing, side of said vehicle; and
(c) an outlet duct configured to direct air exiting said rotor to said outlet on said lateral-facing side of said vehicle.
13. The turbine for extracting energy from air flow as recited in claim 10 , further comprising an inlet door configured to selectively admit said air flow to said rotor.
14. The turbine for extracting energy from air flow as recited in claim 13 , wherein said inlet door is smoothly contoured into a fairing on said moving vehicle.
15. The turbine for extracting energy from air flow as recited in claim 13 , wherein said inlet door acts as said variable inlet ramp.
16. The turbine for extracting energy from air flow as recited in claim 10 , wherein said fairing is part of a wind deflector on the cab of a truck.
17. The turbine for extracting energy from air flow as recited in claim 10 , wherein said fairing is part of a hood on a car.
18. The turbine for extracting energy from air flow as recited in claim 10 , wherein air flow exiting said turbine is directed to an outlet in said vehicle that is remote from said turbine.