MIXED FLOW TWIN SCROLL TURBOCHARGER WITH SINGLE VALVE

• US 20150315961A1
• Filed: 12/02/2013
• Published: 11/05/2015
• Est. Priority Date: 12/21/2012
• Status: Active Grant

• Current Assignee: BorgWarner Incorporated
• Original Assignee: BorgWarner Incorporated
• Inventors: Uhlenhake, Gregory D.
• Granted Patent: US 10,006,345 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: F02B 2037/122 Control of rotational speed of the pump
• CPC Class Codes: F02B 37/12 Control of the pumps
• CPC Class Codes: F02B 37/183 Arrangements of bypass valves or actuators therefor
• CPC Class Codes: F02B 39/08 Non-mechanical drives, e.g. fluid drives having variable gear ratio
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

A turbocharger (100) has an asymmetric, twin scroll volute design, having a first volute (101) and a larger second volute (102). The larger second volute (102) eliminates the need for a wastegate and its associated actuator. The smaller first volute (101) is sized for rapid transients and rated torque, while the second volute (102) is sized such that the turbine inlet pressure is satisfactory for rated power. Furthermore, the turbocharger (100) preferably incorporates a mixed flow turbine wheel (108) rather than a radial wheel, which allows for a larger wheel size to be used while still maintaining inertia. The turbine housing (103) is improved wherein the first and second volutes (101) and (102) are asymmetric with respect to each other and preferably, are leaned toward the bearing housing to match the axial component of the mixed flow turbine wheel inducer (112).

Claims

1. A turbocharger (100) comprising:

a turbine housing (103) and a turbine wheel (108) rotatably disposed therein, said turbine housing (103) defining a smaller sized first volute (101) and a larger second volute (102) which are separated from each other by a volute wall (107) in a twin scroll configuration, said first and second volutes (101) and (102) each discharging into said turbine housing (103) toward said turbine wheel (108), and a volute valve (104) being provided in said volute wall (107) wherein said first and second volutes (101) and (102) are supplied with exhaust gas through a turbine inlet (106) wherein substantially all of said exhaust gas received in said turbine inlet (106) is directed to said first and second volutes (101) and (102), said second volute (102) being selectively closed and opened by said volute valve (104) wherein all of said exhaust gas initially flows exclusively into said first volute (101) when said volute valve (104) is closed and subsequently a portion of said exhaust gas flows into said second volute (102) when said volute valve (104) is opened, said turbine housing (103) having an asymmetric shape defined by the smaller and larger sizes of said first and second volutes (101) and (102) which are angled toward said turbine wheel (108), said turbine wheel (108) being formed as a mixed flow turbine wheel wherein said first and second volutes (101) and (102) are asymmetric in size and orientation relative to said mixed flow wheel (108) such that said larger second volute (102) accommodates rated power and greater exhaust gas flows in comparison to said first volute (101) such that said turbocharger (100) is free of wastegate flow.

2. The turbocharger according to claim 1, wherein said first volute (101) is sized for rated torque, while said second volute (102) is sized such that a turbine inlet pressure is satisfactory for rated power while accommodating a lack of wastegate flow.

3. The turbocharger according to claim 1, wherein said turbocharger (100) has a first operative condition wherein said valve (104) is closed so that exhaust flow is limited to said first volute (101) and a second operative condition wherein said valve (104) is open so that both of said first and second volutes (101) and (102) receive exhaust gas flow.

4. The turbocharger according to claim 3, wherein an angle of discharge of said first and second volutes (101) and (102) which angles away from a bearing housing side of said turbine housing (103) and extends into a throat (109) which opens toward said turbine wheel (108), said first and second volutes (101) and (102) discharging through said throat (109) toward said turbine wheel (108) with both a radially inwardly directed component and an axially directed component.

5. The turbocharger according to claim 4, wherein

said first and second volutes (101) and (102) are leaned closer to said bearing housing side to match an axial component of said mixed flow turbine wheel (108).

6. A turbocharger (100) comprising:

a turbine stage (105) having a turbine housing (103) and a turbine wheel (108) rotatably disposed therein, said turbine housing (103) defining a smaller sized first volute (101) and a larger second volute (102) which are separated from each other by a volute wall (107) in a twin scroll configuration, said first and second volutes (101) and (102) each discharging into said turbine housing (103) toward said turbine wheel (108), and a volute valve (104) being provided in said volute wall (107) wherein said first and second volutes (101) and (102) are supplied with exhaust gas through a turbine inlet (106) wherein substantially all of said exhaust gas received in said turbine inlet (106) is directed to said first and second volutes (101) and (102), said turbine housing (103) having an asymmetric shape defined by the smaller and larger sizes of said first and second volutes (101) and (102) which are angled toward said turbine wheel (108), wherein said first and second volutes (101) and (102) are asymmetric in size and orientation relative to said turbine wheel (108) such that said larger second volute (102) accommodates rated power and increased exhaust gas flows in comparison to said first volute (101), said first volute (101) being sized for rated torque, while said second volute (102) is sized such that a turbine inlet pressure is satisfactory for rated power while accommodating a lack of wastegate flow.

7. The turbocharger according to claim 6, wherein said turbocharger (100) has a first operative condition wherein said valve (104) is closed so that exhaust flow is limited to said first volute (101) and a second operative condition wherein said valve (104) is open so that both of said first and second volutes (101) and (102) receive exhaust gas flow.

8. The turbocharger according to claim 7, wherein said valve (104) is openable incrementally to control starting and increases in exhaust flow into said second volute (102).

9. The turbocharger according to claim 8, wherein said valve (104) is pivotable between closed and opened positions.

10. The turbocharger according to claim 9, wherein said volute (102) is sized substantially larger than said volute (101) to handle any exhaust flow not routed through said first volute (101) so that all exhaust flow is directed to said turbine wheel (108).

11. The turbocharger according to claim 10, wherein said turbine wheel (108) is formed as a mixed flow turbine wheel capable of handling said exhaust flow from said first and second volutes (101) and (102), said first and second volutes (101) and (102) discharging toward said turbine wheel (108) with both a radially inwardly directed component and an axially directed component wherein said axially directed component corresponds to an axial flow component of said mixed flow turbine wheel (108).

12. The turbocharger according to claim 11, wherein the angle of discharge of the volutes (101) and (102) angles away from a bearing housing end of said turbine housing (103).

13. A turbocharger (100) comprising:

a turbine housing (103) and a turbine wheel (108) rotatably disposed therein, said turbine housing (103) defining a smaller sized first volute (101) and a larger second volute (102) which are separated from each other by a volute wall (107) in a twin scroll configuration, said first and second volutes (101) and (102) each discharging into said turbine housing (103) toward said turbine wheel (108), and a volute valve (104) being provided in said volute wall (107) wherein said first and second volutes (101) and (102) are supplied with exhaust gas through a turbine inlet (106) wherein substantially all of said exhaust gas received in said turbine inlet (106) is directed to said first and second volutes (101) and (102), said second volute (102) being selectively closed and opened by said volute valve (104) wherein all of said exhaust gas initially flows exclusively into said first volute (101) and subsequently a portion of said exhaust gas flows into said second volute (102), said turbine housing (103) having an asymmetric shape defined by the smaller and larger sizes of said first and second volutes (101) and (102) which are angled toward said turbine wheel (108), said turbine wheel (108) being formed as a mixed flow turbine wheel (108) wherein said first and second volutes (101) and (102) are asymmetric in size and orientation relative to said mixed flow wheel (108) such that said larger second volute (102) accommodates rated power and greater exhaust gas flows in comparison to said first volute (101) such that said turbocharger (100) is free of wastegate flow, said volutes (101) and (102) being asymmetrically leaned toward a bearing housing side of said turbine housing (103) so as to have an asymmetric shape defined by the smaller and larger sizes of the volutes (101) and (102), and said first and second volutes (101) and (102) discharging toward said turbine wheel (108) with both a radially inwardly directed component and an axially directed component wherein said axially directed component corresponds to an axial flow component of said mixed flow turbine wheel (108).

14. The turbocharger according to claim 13, wherein the angle of discharge of the volutes (101) and (102) angles away from said bearing housing side of said turbine housing (103).

15. The turbocharger according to claim 14, wherein said turbocharger (100) has a first operative condition wherein said valve (104) is closed so that exhaust flow is limited to said first volute (101) and a second operative condition wherein said valve (104) is open so that both of said first and second volutes (101) and (102) receive exhaust gas flow.