Turbocharger with progressively variable A/R ratio

Abstract

An improvement to a turbocharger having a housing (10) with a slot (25) located along a mid-line of the housing (10) above the turbine wheel (29) and a tongue (15) defining the end of an initial inlet throat area (11) of the housing (10), the slot (25) permitting inlet exhaust gas which flows past the tongue (15) to flow into the turbine wheel (29), the improvement being a pivoting vane (50) aligned with the slot (25) and having an upstream end (55) located at a downstream end (57) of the tongue (15). When the vane (50) is in its fully closed position (60), the inlet exhaust gas is prevented from flowing into the slot (25) and, therefore, the turbine wheel (29), until the inlet exhaust gas passes the downstream end (57) of the vane (50). The vane (50) effectively extends the tongue (15) to define a revised inlet throat area (12). The A/R ratio of the housing (10) progressively varies as the vane (50) pivots between the fully opened (70) and fully closed (60) positions.

Claims

1. A turbocharger comprising: a housing (10) defining a volute slot (25) located along a midline of an inner periphery of the housing (10) above a turbine wheel (29); a tongue (15) including a downstream end (17) defining an end of an initial inlet throat area (11/21) of the housing (10); a vane (50) located above and co-aligned with the volute slot (25) and including an upstream end (55) located at a downstream end (17) of the tongue (15); means for pivoting (41) the vane (50) between a fully closed (60), a neutral (65), and a fully opened position (70), the pivot means (41) arranged at the downstream end (17) of the tongue (15) and the upstream end (55) of the vane (50); a downstream end (57) of the vane (50) defining a second inlet throat area (23) having a same cross-sectional area as the initial inlet throat area (11/21) when the vane (50) is in the fully opened position and a reduced cross-sectional area when the vane (50) is in the fully closed position; wherein when the vane (50) is in the fully opened position (70), the downstream end (57) of the vane (50) is adjacent an outer wall (27) of the housing (10) and the volute slot (25) is unobstructed by the vane (50) and inlet exhaust gas which flows into the initial inlet throat area (11/21) first enters the volute slot (25) at the downstream end (17) of the tongue (15); and wherein when the vane (50) is in the fully closed position (60), the downstream end (57) of the vane is adjacent the turbine wheel (29) and the volute slot (25) is blocked by the vane (50) up to the downstream end (57) and the inlet exhaust gas which flows into the initial inlet throat area (11/21) and the second inlet throat area (23) first enters the volute slot at the downstream end (57) of the vane (50).

2. A turbocharger according to claim 1 wherein the area/radius ratio of the housing (10) progressively varies as the vane (50) pivots between the fully opened (70) and fully closed positions (60).

3. A turbocharger according to claim 1 wherein in the fully opened position (70) the flow of the inlet exhaust gas is unevenly distributed above and below the vane (50).

4. A turbocharger according to claim 1 wherein the overall length of the vane 50 is sized to provide a predetermined area/radius ratio of the turbocharger when the vane (50) is in the fully closed position (60) yet still clear the turbine wheel (29) when moving into the fully opened position (70).

5. A turbocharger according to claim 1 wherein when the vane (50) is in the fully closed position (60) the downstream end (57) of the vane (50) extends to 180 of the volute slot (25).

6. A turbocharger according to claim 1 wherein the vane (50) is wider than the volute slot (25).

7. A turbocharger according to claim 1 wherein the upstream end (55) of the vane (50) is at a different height relative to the slot (25) than is the downstream end (57) of the vane (50).

8. A turbocharger according to claim 1 further comprising a vertical divider wall (40) located above and attached to the vane (50).

9. A turbocharger according to claim 8 wherein when the vane (50) is in the fully closed position (60), the vertical divider wall (40) defines a first and a second volute (13) of the housing (10).

10. A turbocharger according to claim 1 further comprising a vertical divider wall (40) located in the initial inlet throat area (11) of the housing (10), upstream of an upstream end (55) of the vane (50).

11. A turbocharger according to claim 1 wherein the pivot means (41) does not obstruct the flow of inlet exhaust gas flowing through the initial inlet throat area (11) of the housing (10).

12. A turbocharger according to claim 1 wherein the vane (50) is a fixed length.

13. A turbocharger according to claim 1 wherein the vane (50) is a rigid vane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cross section of a preferred embodiment of a turbocharger with progressively varying A/R ratio made according to this invention. The housing includes two dividers, one fixed, the other moveable. The fixed divider (or flow splitter) is located entirely within the inlet or throat section of the housing. The moveable (or pivoting) divider, which is shown in its fully open position, begins at the end of the fixed throat divider and then extends past the end of the tongue. The moveable divider includes pivot means for allowing it to move between the fully open and fully closed position and includes a volute slot blocker or vane attached to its lower end (and outside of the original inlet or throat section of the housing). A secondary housing (not shown) and covers the divider and prevents exhaust gas from escaping the turbocharger housing.

(2) FIG. 2 is a cross-section of the turbocharger of FIG. 1 with the moveable divider shown in the fully closed position. In the fully closed position, the upstream end of the volute slot blocker or vane meets up with the tongue end of the housing, thereby altering the A/R ratio by extending the tongue to the downstream end of the vane.

(3) FIG. 3 is an end view of the throat or inlet section to the turbocharger fitted with the volute slot blocker or vane of FIG. 4. The pivot means are located at the horizontal centerline of the inlet above the tongue end.

(4) FIG. 4 is an isometric view of an alternate embodiment of the volute slot blocker or vane. The moveable divider wall of FIG. 1 has been eliminated along with the fixed divider.

(5) FIG. 5 is a view of the vane of FIG. 4 in its closed position. The vane preferably blocks the first 180 degrees of the volute slot. The vane could extend past 180 but anything more than 185 would require additional means to pivot the vane away when moving toward the open position and still clear the turbine wheel housing.

(6) FIG. 6 is a top view of the vane of FIG. 4 with a portion of the housing cut away to show the vane.

(7) FIG. 7 is a cross section of another preferred embodiment of a turbocharger with progressively varying A/R ratio made according to this invention. A volute slot blocker, shown in its open position here and arranged at the downstream end of the tongue, pivots downward toward the turbine wheel and effectively moves the end of the tongue (and, therefore, the inlet or throat section) further downstream to a place of reduced cross sectional area, thereby resulting in a reduced A/R ratio.

(8) FIG. 8 is a cross section of the turbocharger of FIG. 6, with the volute slot blocker in its fully closed position.

(9) FIG. 9 is an end view of the throat or inlet section to the turbocharger taken along section line 9-9 of FIG. 8. The pivot means are located at the downstream end of the tongue, thereby not obstructing the original throat or inlet section area (compare FIG. 3).

(10) FIG. 10 is a graph comparing the boost gain of a turbocharger fitted with the embodiment of FIGS. 6-8. with and without the volute slot blocker.

(11) FIG. 11 is a graph comparing a dynamometer run of the same turbocharger with and without the volute slot blocker of FIGS. 6-8. The turbocharger with the volute slot blocker makes more power and achieves peak power about 2 seconds faster.

(12) FIG. 12A is an animation illustrating exhaust air flow as it flows from the exhaust air inlet to the wheel with the vane closed and the pivot point of the vane not obstructing the initial inlet throat area.

(13) FIG. 12B is an animation illustrating the exhaust air flow when the pivot point of the vane is arranged at the centerline of the initial throat area.

(14) FIG. 13A is an animation illustrating the vane arrangement of FIG. 12A when the vane is opened at about 40 (as measured from the 180 point of the volute slot).

(15) FIG. 13B is an animation illustrating the vane arrangement of FIG. 12B when the vane is opened at about 25.

ELEMENT NUMBER AND ELEMENTS USED IN THE DRAWINGS

(16) 10 Housing 11 Inlet passageway or throat section 12 Extended inlet passageway or throat section 13 Volute 15 Tongue 17 Tongue tip or end 19 Exhaust gas inlet side 21 Cross section of 11 23 Reduced cross section downstream of 11 25 Volute slot above turbine inducer or wheel 27 Wall 29 Turbine inducer or wheel area 30 Fixed divider or vertical wall (flow splitter) 31 Downstream end of 30 40 Moveable divider or vertical wall 41 Pivot shaft 45 Upstream end of 40 47 Lower end of 40 50 Volute slot blocker or vane 53 Pivot arm 55 Upstream end of 50 57 Downstream end of 50 60 Fully closed position 65 Neutral position 70 Fully opened position

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(17) Referring to the drawings, and first to FIGS. 1 and 2, a preferred embodiment of a turbocharger with an adjustable or progressively variable A/R ratio made according to this invention includes a housing 10 having two vertical walls or dividers of fixed length, one non-moveable or fixed 30, the other moveable 40. The fixed divider or flow splitter 30 is located entirely within the inlet or throat section 11 of the housing 10 and preferably has an arcuate (concave-shaped) downstream end 31 or, alternatively, a straight end (not shown). The moveable (or pivoting) divider 40, which is shown in its fully opened position in FIG. 1, begins at the downstream end 31 of the fixed divider 30 and then extends past the end 17 of the tongue 15.

(18) Housing 10 is a radial inflow housing, meaning that the housing 10 has a volute 13 that continuously decreases in area and cross section to help maintain even pressure all the way around the turbine inducer or wheel area 29. The inlet or throat section 11 of the housing 10 begins at the exhaust inlet side 19 and extends to the end 17 of the tongue 15. This invention effectively extends that original throat section 11 further downstream in the volute 13 to an area of reduced cross section 23 relative to that of the original or unaltered throat cross section 21 (see FIG. 7 showing cross section 21 being defined by a cutting plane line that passes through the inlet passageway or throat section 11 at the tip or end 17 of the tongue 15 to the opposing wall 27 of the inlet passageway 11 and cross section 23 being farther downstream defining an extended throat section 12).

(19) The moveable divider 40 includes pivot means for allowing it to move between the fully open and fully closed positions 70, 60 (see e.g. FIG. 7). The pivot means is preferably a shaft 41 in communication with electrical or pneumatic control means of a kind known in the art (see e.g., U.S. Pat. No. 7,481,056 to Blaylock, the contents of which is hereby incorporated by reference). The control means is sized to withstand and overcome any backpressure exerted by the divider 40 and vane volute slot blocker or vane 50 (discussed below) when moving between the closed and open positions 60, 70.

(20) The shaft 41 is not in contact with the upper wall 27 of the housing 10 but rather is arranged at the horizontal center line of the throat section 11. The upstream end 45 of the divider 40 preferably has an arcuate (convex) forward end or straight end complementary in shape to the fixed splitter's downstream end 31.

(21) The moveable divider 40 also includes a rigid (non-flexible), volute slot blocker or vane 50 attached to the lower end 47 of the divider 40. The upstream end 55 of the vane 50 begins at the end 17 of the tongue 15.

(22) When the moveable divider 40 is in the fully open position, the A/R ratio of the housing 10 remains unchanged. The divider 40 opens up the volute 13 and provides a single volute design to the housing 10, with exhaust gas flow flowing between the end 17 of the tongue 15 and the upstream end 55 of the vane 50 (and therefore under and over the vane 50) until it eventually flows into the turbine inducer or wheel area 29.

(23) When the moveable divider 40 is in the fully closed position, the upstream end 55 of the volute slot blocker or vane 50 meets up with the end 17 of the tongue 15, and the moveable divider 40 provides a dual volute 13 housing 10. The A/R ratio is altered because the tongue end 17 (and therefore the inlet passageway or throat section 11) has been extended by the vane 50 toward the downstream end 57 of the vane 50.

(24) This extension effectively brings the tongue end 17 to a place of reduced cross sectional area 23 relative to the original inlet or throat cross sectional area 21, thereby resulting in a reduced A/R ratio. For example, when in the closed position, the vane 50 turns a 0.88 A/R turbine housing (i.e., a housing with the vane 50 in a fully retracted position or a housing without the vane 50) into a 0.40 A/R turbine housing.

(25) As the moveable divider 40 and volute slot blocker or vane 50 move to intermediate positions (e.g. 65) between the fully opened and fully closed positions 60, 70, the A/R ratio is progressively varied. Using the above example, the A/R ratio can progressively vary between 0.88 and 0.40. However, the length of the vane 50 can be any length that provides a desired A/R ratio when the vane 50 is in the fully closed position 60 yet still clear the turbine inducer or wheel area 29 when moving into the fully opened position 70, with shorter lengths being less effective than longer lengths.

(26) When the movable divider 40 is in its fully open position, the divider 40 extends beyond the original housing 10. A secondary housing (not shown) is needed to cover the divider 30 and prevent exhaust gas from escaping the housing 10.

(27) Referring now to FIGS. 3-6, an alternate preferred embodiment of a turbocharger with an adjustable or progressively variable A/R ratio made according to this invention includes a housing 10 having the volute slot blocker or vane 50 of fixed length without the fixed and moveable dividers 20, 40 of FIGS. 1-3. Similar to that other embodiment, vane 50 preferably blocks the first 180 degrees of the volute slot 25 when the vane 50 is in the fully closed position (see e.g., FIG. 5). The pivot shaft 41 is located at the horizontal centerline of the inlet or throat section 11 above the downstream end 17 of the tongue 15. Preferably, the vane 50 is arranged such that exhaust gas flow passing over the downstream end 57 of the vane 50 is prevented from passing between the vane 50 and where it meets the downstream or tip end 17 of the tongue 15 (see e.g., FIGS. 12A-13B).

(28) Animations show that leaving the inlet 11 unobstructed by the shaft 41 (and arm 53) produces a much smoother flow of exhaust gas in the volute 13, through the slot 25 and into the turbine inducer or wheel area 29 (see FIGS. 12A-13B, the arrows showing the flow, the line weight of the arrows indicating velocity, with the line weight increasing as velocity increases; note the flow exits the turbine wheel but is not illustrated). Also, placing shaft 41 in the center of the inlet creates backpressure, even if knifing means (not shown) are placed upstream of it. Ideally, the backpressure-to-boost ratio is about 1:1.

(29) Therefore, in the embodiment of FIGS. 7-9, the pivot shaft 41 is located below the inlet cross sectional area 21 so that the shaft 41 does not obstruct the inlet cross sectional area 21 at any time. The pivot point or shaft 41 does not contact the upper wall 27. Preferably, only a single pivot shaft 41 is used in this and the other embodiment. Also preferably the vane 50 is arranged such that exhaust gas flow passing over the downstream end 57 of the vane 50 is prevented from passing between the vane 50 and where it meets the downstream or tip end 17 of the tongue 15 (see e.g., FIGS. 12A-13B).

(30) Additionally, the angled pivot arm 53 in the embodiment of FIGS. 3-6 has been eliminated. The upstream end 55 of the vane 50 is attached at the end 17 of the tongue, which permits the vane to close the first 180 of the slot 25 completely (and also makes the vane stronger compared to a design which places the pivot point at a min-point of the vane). Preferably, the upstream end 55 is set lower or deeper relative to the volute slot 25 than is the downstream end 57 of the vane 50. In a preferred embodiment, the upstream end 55 was set about inch (0.317 cm) lower than the downstream end 57.

(31) Vane 50 can be sized such that it can be received by the volute slot 25 yet still block flow into the slot 25 (e.g., inch (1.27 cm)) or can be sized wider than the slot 25. Making vane 50 wider than slot 25 serves to raise the vane 50 higher in the volute 13, thereby decreasing the cross-sectional area above the vane 50. The same holds true for the other preferred embodiments

(32) The fully open position 70 is above the full intermediate or neutral position 65 which, in turn, is above the fully closed position 60 (see FIGS. 7 & 8). The neutral position 65 essentially splits or defines volute 13 into an upper and lower half, with an equal volume of exhaust flowing over and under the vane 50. The vane 50 can pivot from any one of those positions 60 65, 70 to another as well as any position in between each of those. As the volute slot blocker or vane 50 pivots downward from the open position 70 toward the turbine inducer or wheel areaa 29, the vane 50 effectively moves the tongue end 17 (and, therefore, the inlet or throat section 11) further downstream to a place of reduced cross sectional area 23, thereby resulting in a reduced A/R ratio. When in any position other than the fully open position 70, the A/R ratio of the turbocharger is altered.

(33) When vane 50 is in the closed position, tests showed a 3,000 RPM increase in turbine wheel speed at idle. By way of comparison, the Blaylock moveable vane, discussed in the Background section, shows a 500 RPM increase at idle. A reason for this is the Blaylock moveable vane cannot close off flow to the turbine wheel completely. Vane 50 can close off the flow to 180 of the slot 25. Similar to the other preferred embodiments, the length of the vane 50 can be any length that provides a desired A/R ratio when the vane 50 is in the fully closed position 60 yet still clear the turbine wheel when moving into the fully opened position 70, with shorter lengths being less effective than longer lengths.

(34) FIG. 10 shows the boost gain of a turbocharger without a volute slot blocker and the same turbocharger fitted with the embodiment of FIGS. 4-8. FIG. 11 compares a dynamometer run of the same turbocharger with and without the volute slot blocker 50. The turbocharger with the volute slot blocker 50 makes more power and achieves peak power about 2 seconds faster.

(35) While preferred embodiments of the turbocharger have been described, the invention itself is defined by the following claims.