Throttle body with fluid flow control

1. A throttle body, comprising:

a body having a main bore from which a fuel and air mixture is discharged for use by an engine;

a throttle valve shaft carried by the body for rotation relative to the body,

a throttle valve head carried by the throttle valve shaft and moveable between an idle position and an open position to control at least some fluid flow through the main bore; and

a boost venturi open to the main bore;

wherein the throttle valve head includes a non-planar portion that defines a flow directing feature to alter at least one of the velocity or direction of at least a portion of the fluid that flows in the main bore and relative to the boost venturi, wherein the main bore has an axis, and the boost venturi has an axis that is radially offset from the axis of the main bore, wherein the flow directing feature is oriented to increase air flow through the boost venturi when the throttle valve head is in the open position, wherein the boost venturi includes a projection that extends upstream of an inlet of the boost venturi and wherein the projection is arranged to direct air into the inlet of the boost venturi.

2. The throttle body of claim 1 wherein the flow directing feature includes a portion of the throttle valve head that is angled relative to an adjacent portion of the throttle valve head.

3. The throttle body of claim 2 wherein the portion of the throttle valve head that is angled relative to an adjacent portion of the throttle valve head is provided at an upstream portion of the throttle valve head relative to the orientation of the throttle valve head in the open position.

4. The throttle body of claim 2 wherein the portion of the throttle valve head that is angled relative to an adjacent portion of the throttle valve head is provided at a downstream portion of the throttle valve head relative to the orientation of the throttle valve head in the open position.

5. The throttle body of claim 1 wherein the flow directing feature is defined by one or more projections extending from the throttle valve head.

6. The throttle body of claim 5 wherein the projections define a channel through which air flows, and the channel is arranged to alter the velocity of air flowing therein.

7. The throttle body of claim 6 wherein the channel is centered about a plane that includes the axis of the boost venturi.

8. The throttle body of claim 1 wherein two flow directing features are provided on the throttle valve head with a channel defined between the flow directing features and wherein the channel is aligned with the boost venturi.

9. The throttle body of claim 1 which also includes a main fuel outlet through which fuel is discharged into the main bore and wherein the main fuel outlet opens into the boost venturi.

10. The throttle body of claim 1 which also includes a main fuel outlet through which fuel is discharged into the main bore and wherein the flow directing feature directs a portion of the air flowing in the main bore at the main fuel outlet.

11. The throttle body of claim 1 wherein the throttle valve shaft does not intersect the axis of the main bore, and wherein the throttle valve head divides the portion of the main bore in which the throttle valve head is received into a first section and a second section, the axis of the boost venturi extends through the first section and the flow directing feature directs air away from the second section and toward the first section.

12. The throttle body of claim 11 wherein the first section is larger than the second section.

13. The throttle body of claim 1 wherein the projection is received against a surface that defines the main bore, and wherein the projection is inclined from an upstream end that is adjacent to said surface to a downstream end adjacent to the inlet of the boost venturi.

14. A throttle body, comprising:

a body having a main bore from which a fuel and air mixture is discharged for use by an engine and a fuel passage leading to the main bore to provide fuel into the main bore;

a throttle valve head carried by the body and moveable between an idle position and a wide open position to control at least some fluid flow through the main bore;

a boost venturi supported in the main bore at least in part by a flange of the boost venturi that is engaged with the body, the boost venturi having an inlet open to the main bore at a location downstream of the throttle valve head, an outlet open to the main bore and a passage extending between the inlet and the outlet; and

a flow directing feature associated with the throttle valve head to alter at least one of the velocity or direction of at least a portion of the fluid that flows in the main bore and relative to the inlet of the boost venturi, and the fuel passage opens into the passage of the boost venturi so that fuel from the fuel passage is mixed with air flowing through the passage of the boost venturi and then discharged from the outlet into the main bore for mixing with air in the main bore, wherein the fuel passage is defined partially by a rod extending between the body and the boost venturi, and the rod is separate from the flange and also supports the boost venturi within the main bore, wherein the boost venturi directly engages a surface of the body that defines the main bore.

15. The throttle body of claim 14 wherein a main fuel outlet is defined in the boost venturi.

16. The throttle body of claim 14 wherein the flow directing feature includes a portion of the throttle valve head that is angled relative to an adjacent portion of the throttle valve head.

17. The throttle body of claim 14 wherein the flow directing feature is defined by one or more projections extending from the throttle valve head.

18. The throttle body of claim 17 wherein the projections define a channel through which air flows, and the channel is arranged to alter the velocity of air flowing therein.