Twin scroll turbocharger device with bypass

Abstract

A twin scroll turbocharger device for an internal combustion engine includes a turbine and a compressor, wherein the turbine comprises a first turbine scroll and a second turbine scroll, and wherein at least the first turbine scroll is provided with a turbine scroll inlet valve such that the exhaust gas flow through the first turbine scroll is controllable. The twin scroll turbocharger device is further characterized in that a bypass conduit is provided between a compressor and at least the first turbine scroll. The bypass conduit is provided with a bypass conduit valve such that a flow through the bypass conduit is controllable.

Claims

1. A twin scroll turbocharger device for an internal combustion engine, the twin scroll turbocharger device comprising: a turbine with a turbine wheel configured to be driven by exhaust gas guided from the internal combustion engine, the turbine further comprising a first turbine scroll and a second turbine scroll, wherein the first turbine scroll is provided with a first turbine scroll inlet valve at a first turbine scroll inlet to control the exhaust gas flow through the first turbine scroll inlet of the first turbine scroll; and wherein the second turbine scroll is provided with a second turbine scroll inlet valve at a second turbine scroll inlet to control the exhaust gas flow through the second turbine scroll inlet of the second turbine scroll; a compressor with a compressor wheel connected to and configured to be driven by the turbine wheel to pump compressor gas to the internal combustion engine; a turbocharger housing enclosing the turbine and the compressor; and a bypass conduit that connects a pressurized portion of the compressor with the first and second turbine scrolls at a respective portion of each turbine scroll provided downstream, in relation to the exhaust gas flow, of a respective turbine scroll inlet valve, wherein the bypass conduit is configured to allow fluid communication between the compressor and the first and second turbine scrolls; and wherein the bypass conduit is provided with a bypass conduit valve that is configured to control fluid flow from the pressurized portion of the compressor through the bypass conduit if the compressor is in fluid communication with the first turbine scroll and/or the second turbine scroll.

2. The twin scroll turbocharger device according to claim 1, wherein the first and second turbine scrolls are arranged side by side with reference to a rotational direction of the turbine wheel.

3. The twin scroll turbocharger device according to claim 1, wherein the first turbine scroll is arranged outwardly in a radial direction with reference to the turbine wheel of the second turbine scroll.

4. The twin scroll turbocharger device according to claim 1, wherein the first and second turbine scrolls have equal cross sectional flow areas.

5. The twin scroll turbocharger device according to claim 1, wherein the first turbine scroll has a larger cross sectional flow area than the second turbine scroll.

6. The twin scroll turbocharger device according to claim 1, wherein the second turbine scroll has a larger cross sectional flow area than the first turbine scroll.

7. A method of controlling a twin scroll turbocharger device for an internal combustion engine, wherein the twin scroll turbocharger device comprises: a turbine with a turbine wheel driven by exhaust gas guided from the internal combustion engine, wherein the turbine further comprises a first turbine scroll and a second turbine scroll; wherein the first turbine scroll is provided with a first turbine scroll inlet valve at a first turbine scroll inlet, and the first turbine scroll inlet valve is controllable to be between an open position and a closed position to control the exhaust gas flow through the first turbine scroll; and wherein the second turbine scroll is provided with a second turbine scroll inlet valve at a second turbine scroll inlet to control the exhaust gas flow through the second turbine scroll inlet of the second turbine scroll; a compressor with a compressor wheel connected to and driven by the turbine wheel to pump compressor gas to the internal combustion engine; a turbocharger housing enclosing the turbine and the compressor; and a bypass conduit provided between a pressurized portion of the compressor and each of a portion of the first turbine scroll provided downstream, in relation to the exhaust gas flow, of the first turbine scroll inlet valve, and a portion of the second turbine scroll provided downstream, in relation to the exhaust gas flow, of the second turbine scroll inlet valve, the bypass conduit allowing fluid communication between the compressor and at least one of the first turbine scroll and the second turbine scroll, wherein the bypass conduit is provided with a controllable bypass conduit valve that is controllable to be in a closed position or in a position open to at least one of the first scroll inlet valve and the second scroll inlet valve to control the exhaust gas flow through the bypass conduit; the method comprising: when an exhaust gas flow from the internal combustion engine is equal to or less than a predetermined low flow, via an engine control unit, closing the first turbine scroll inlet valve; and opening the bypass conduit valve such that fluid flows from the pressurized portion of the compressor to the first turbine scroll, while the exhaust gas flow flows through the second turbine scroll.

8. The method according to claim 7, wherein the bypass conduit is provided between the pressurized portion of the compressor and each of the portion of the first turbine scroll provided downstream, in relation to the exhaust gas flow, of the first turbine scroll inlet valve and a portion of the second turbine scroll provided downstream, in relation to the exhaust gas flow, of a second turbine scroll inlet valve, wherein the bypass conduit allows fluid communication between the compressor and the first and second turbine scrolls; and wherein the bypass conduit valve is configured to control fluid flow from the pressurized portion of the compressor through the bypass conduit if the compressor is in fluid communication with at least one of the first turbine scroll and the second turbine scroll; wherein the second turbine scroll is provided with the second turbine scroll inlet valve at a second turbine scroll inlet; wherein the second turbine scroll inlet valve is controllable to be between an open position and a closed position to control the exhaust gas flow through the second turbine scroll; and wherein the method further comprises: when the exhaust gas flow from the internal combustion engine increases to be higher than the predetermined low flow but lower than a predetermined high flow, via the engine control unit, opening the first turbine scroll inlet valve; closing the second turbine scroll inlet valve; and opening the bypass conduit valve such that fluid flows from the pressurized portion of the compressor through the bypass conduit to the second turbine scroll, while the exhaust gas flow flows through the first turbine scroll.

9. The method according to claim 8 further comprising: when the exhaust gas flow from the internal combustion engine is equal to or exceeds the predetermined high flow, via the engine control unit, opening all turbine scroll inlet valves, and closing the bypass conduit valve, while the exhaust gas flow flows through the first and second turbine scrolls.

10. The method according to claim 7, wherein the bypass conduit is provided between the pressurized portion of the compressor and each of the portion of the first turbine scroll provided downstream, in relation to the exhaust gas flow, of the first turbine scroll inlet valve and a portion of the second turbine scroll provided downstream, in relation to the exhaust gas flow, of a second turbine scroll inlet valve; wherein the bypass conduit valve is configured to control a flow through the bypass conduit and to control if the compressor is in fluid communication with the at least one of the first turbine scroll and the second turbine scroll; wherein the second turbine scroll is provided with the second turbine scroll inlet valve at a second turbine scroll inlet, wherein the second turbine scroll inlet valve is controllable to be between an open position and a closed position to control the exhaust gas flow through the second turbine scroll; and wherein the method further comprises: when the exhaust gas flow from the internal combustion engine decreases to be lower than a predetermined high flow but higher than the predetermined low flow, via the engine control unit, closing the second turbine scroll inlet valve; and opening the bypass conduit valve such that fluid flows from the pressurized portion of the compressor through the bypass conduit to the second turbine scroll, while the exhaust gas flow flows through the first turbine scroll.

11. The method according to claim 7, wherein the bypass conduit is provided between the pressurized portion of the compressor and each of the portion of the first turbine scroll provided downstream, in relation to the exhaust gas flow, of the first turbine scroll inlet valve and a portion of the second turbine scroll provided downstream, in relation to the exhaust gas flow, of a second turbine scroll inlet valve; wherein the bypass conduit valve is configured to control a flow through the bypass conduit and to control if the compressor is in fluid communication with the at least one of the first turbine scroll and the second turbine scroll; wherein the second turbine scroll is provided with the second turbine scroll inlet valve at a second turbine scroll inlet; wherein the second turbine scroll inlet valve is controllable to be between an open position and a closed position to control the exhaust gas flow through the second turbine scroll; and wherein the method further comprises: when the exhaust gas flow from the internal combustion engine decreases to be equal to or lower than the predetermined low flow, via the engine control unit, closing the first turbine scroll inlet valve; opening the second turbine scroll inlet valve; and opening the bypass conduit valve such that fluid flows from the pressurized portion of the compressor through the bypass conduit to the first turbine scroll, while the exhaust gas flow flows through the second turbine scroll.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) With reference to the appended drawings, below follows a more detailed description of embodiments according to the disclosure cited as examples.

(2) FIG. 1 discloses a schematic view of an Internal Combustion Engine (ICE) provided with an example of a twin scroll turbocharger device according to the present disclosure;

(3) FIG. 2A discloses a preferred embodiment of a twin scroll turbocharger device according to the present disclosure;

(4) FIG. 2B discloses another preferred embodiment of a twin scroll turbocharger device according to the present disclosure;

(5) FIG. 3 discloses yet another preferred embodiment of a twin scroll turbocharger device according to the present disclosure; and

(6) FIG. 4 schematically discloses three examples of operating modes of a twin scroll turbocharger device according to the present disclosure.

DETAILED DESCRIPTION

(7) As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary and that various and alternative forms may be employed. The figures are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art.

(8) FIG. 1 discloses a schematic engine arrangement 1 comprising an ICE 3 provided with an example of a twin scroll turbocharger device 2 according to the present disclosure. The ICE 3 comprises an exhaust manifold 4 and an intake manifold 5, wherein exhaust gas from the ICE 3 are discharged from the exhaust manifold into a turbine inlet 6 via one or more conduits 6a. The exhaust gas drives a turbine wheel 7a of a turbine 7 of the twin scroll turbocharger device 2 and is subsequently discharged through a turbine outlet 8. The turbine wheel 7a is connected to a compressor wheel 9a of a compressor 9 by an axis 19. The twin scroll turbocharger device 2 is enclosed by a turbocharger housing 18.

(9) The compressor is fed compressor gas, preferably ambient air, from a compressor inlet 10. The compressed gas is compressed in the compressor 9 and subsequently discharged from the compressor 9, through the compressor outlet 11 whereby it is guided to the inlet manifold 5 via one or more conduits 11a. Further, the turbine 7 of the twin scroll turbocharger device 2 comprises a first and a second turbine scroll 12a, 12b and additionally a bypass conduit 13 provided with a bypass conduit valve 14. The bypass conduit 13 connects the compressor 9 with the first turbine scroll 12a of the turbine 7 such that the compressor 9 is in fluid communication with first turbine scroll 12a, whereby bypass between the compressor 9 and the first turbine scroll 12a is enabled. FIG. 1 also discloses a first turbine scroll inlet 15a wherein the first turbine scroll inlet 15a is provided with a first turbine scroll inlet valve 16a.

(10) FIG. 2A discloses the preferred embodiment of a twin scroll turbocharger device 2 as described in relation to FIG. 1 wherein the twin scroll turbocharger device 2 comprises a first and a second turbine scroll 12a, 12b arranged side by side. The embodiment of the twin scroll turbine device 2 of FIG. 2A discloses how improved turbocharger efficiency can be obtained by providing bypass functionality from the compressor 9 to the first turbine scroll 12a of the turbine 7. FIG. 2A discloses the first and a second turbine scroll inlet 15a, 15b, wherein the first turbine scroll inlet 15a is provided with the first turbine scroll inlet valve 16a. The first turbine scroll inlet valve 16a is configured to control the flow through the first scroll 12a. The twin scroll turbocharger device 2 is provided with a bypass conduit 13 comprising a bypass conduit valve 14, wherein the bypass conduit valve 14 is configured to at least control the flow from a compressor 9 through the bypass conduit 13. The embodiment of the twin scroll turbocharger device 2 disclosed in FIG. 2A enables that at low exhaust gas flows from the ICE, such as when operating the ICE at low revolutions, the first turbine scroll inlet valve 16a is set to be closed.

(11) Closing one of the turbine scroll inlets 15a will increase the exhaust gas flow through the remaining, open second turbine scroll inlet 15b, wherein the flow rate of the exhaust gas through the second turbine scroll 12b in fluid communication with the open second turbine scroll inlet 15b is increased. By setting the bypass conduit valve 14 to be open bypass through the bypass conduit 13, from the turbine 7 to the first turbine scroll 12a, is obtained. Providing such bypass functionality has many advantages such as counteracting compressor surge and improving the overall ICE efficiency.

(12) FIG. 2B discloses another preferred embodiment of a twin scroll turbocharger device 2 according to the present disclosure. The embodiment of the twin scroll turbocharger device 2 has the same characteristics as previously described in relation to the embodiment disclosed in FIG. 2A, but according to the embodiment disclosed in FIG. 2B the first turbine scrolls 12a is arranged outwardly in a radial direction of said second turbine scroll 12b with reference to said turbine wheel 7a. In accordance with what was disclosed in relation to FIG. 2A; the first turbine scroll 12a is arranged to be in fluid communication with the first turbine scroll inlet 15a. In order to provide the bypass functionality from the compressor 9 as previously described the first turbine scroll inlet 15a is provided with a first turbine scroll inlet valve 16a and the bypass conduit 13 is connected to be in fluid communication with the first turbine scroll 12a. Providing one turbine scroll 12a outwardly in a radial direction of another turbine scroll 12b has the advantage that the leakage between the turbine scrolls 12a, 12b is minimized due to the smaller separating wall compared to a side by side scroll embodiment.

(13) Referring now to FIG. 3, that figure discloses yet another preferred embodiment of the present disclosure. The embodiment of the twin scroll turbocharger device 2 disclosed in FIG. 3 discloses how the first and second turbine scrolls 12a, 12b may be configured in order to further improve the efficiency of the twin scroll turbocharger device 2. According to the embodiment disclosed in FIG. 3 the twin scroll turbocharger device 2 comprises a first and second turbine scroll 12a, 12b with different cross sectional flow areas, wherein the first turbine scroll 12a has a larger cross sectional flow area than the second turbine scroll 12b. Additionally, the bypass conduit 13 is provided to be connected to the compressor 9 and to both the first and second turbine scrolls 12a, 12b, such that both the first and second turbine scrolls 12a, 12b may be in fluid communication with the compressor 9. Further, according to the embodiment of the twin scroll turbocharger device 2 disclosed in FIG. 3 the bypass conduit 13 is provided with a bypass conduit valve 14. According to a preferred embodiment of the present disclosure the bypass conduit valve 14 has the functionality to:

(14) control the bypass flow through the bypass conduit 13, and

(15) control if the first turbine scroll 12a, the second turbine scroll 12b or both the first and the second turbine scrolls 12a, 12b is/are set to be in fluid communication with the compressor 9 (when the bypass is activated).

(16) The embodiment of the twin scroll turbocharger device 2 further comprises a first and a second turbine scroll inlet 15a, 15b with a first and second turbine scroll inlet valve 16a, 16b. The first turbine scroll inlet 15a is preferably connected to the first turbine scroll 12a and the second turbine scroll inlet 15b is preferably connected to the second turbine scroll 12b, such that respective turbine scroll inlet 15a, 15b is in fluid communication with respective turbine scroll 12a, 12b. Providing the first and second turbine scroll inlets 15a, 15b with the first and second turbine scroll inlet valves 16a, 16b, and providing the bypass conduit 13 with the bypass conduit valve 14, enables that the twin scroll turbocharger device 2 can be operated in at least three discrete operating modes;

(17) a first operating mode wherein the second turbine scroll inlet valve 16b is open, the first turbine scroll inlet valve 16a is closed and the bypass conduit valve 14 is set such that bypass is provided to the first turbine scroll 12a,

(18) a second operating mode where the first turbine scroll inlet valve 16a is open, the second turbine scroll inlet valve 16b is closed and the bypass conduit valve 14 is set such that bypass is provided to the second turbine scroll 12b, and

(19) a third operating mode where the first and second turbine scroll inlet valves 16a, 16b are open and the bypass conduit valve 14 is set to be closed.

(20) The first operating mode may be preferred when the exhaust gas flow entering the turbine inlet is low, the second operating mode may be preferred when the exhaust gas flow entering the turbine inlet is intermediate and the third operating mode may be preferred when the exhaust gas flow is relatively high. What actual exhaust gas flow respective low, intermediate and high exhaust gas flows represent may e.g., be dependent of turbocharger specific characteristics. This will be further disclosed in relation to FIG. 4 below.

(21) At specific operating conditions it may also be advantageous to set the first and second turbine scroll inlet valves 16a, 16b and the bypass conduit valve 14 to be open. As is apparent for a person skilled in the art the twin scroll turbocharger device 2 may also be operated at operating modes between the first, second and third mode where respective valve is partially closed and/or partially open. This applies to all embodiments disclosed herein.

(22) FIG. 4 refers to the embodiment previously disclosed in relation to 2A but with a bypass conduit valve 14 as disclosed in relation to FIG. 3. Further, FIG. 4 discloses the flow through the first and second scroll 12a, 12b and the bypass conduit 13 in the three operating modes OM1, OM2, OM3 as previously disclosed in relation to FIG. 3. In the embodiment disclosed in FIG. 4 the first and second turbine scrolls 12a, 12b have the same cross sectional flow area, and respective scroll is provided with a first and second turbine scroll inlet 15a, 15b with a respective first and second turbine scroll inlet valve 16a, 16b. The bypass conduit 13 is provided with a bypass valve 14 such that the flow through the bypass conduit 13 and to respective turbine scroll 12a, 12b is controllable.

(23) In the first operating mode OM1 the second turbine scroll inlet valve 16b is open, the first turbine scroll inlet valve 16a is closed and the bypass conduit valve 14 is set such that bypass is provided to the first turbine scroll 12a.

(24) In the second operating mode OM2 the first turbine scroll inlet valve 16a is open, the second turbine scroll inlet valve 16b is closed and the bypass conduit valve 14 is set such that bypass is provided to the second turbine scroll 12b.

(25) In the third operating mode OM3 the first and second turbine scroll inlet valves 16a, 16b are open and the bypass conduit valve 14 is set to be closed.

(26) The operating modes OM1, OM2, OM3 of the present disclosure as disclosed in, and described in relation to, FIGS. 3 and 4 is particularly advantageous if being implemented for a twin scroll turbocharger device 2 as disclosed in FIG. 3, wherein the first and second turbine scrolls 12a, 12b are provided to have different cross sectional flow areas. However, even when the first and second scrolls 12a, 12b have the same cross sectional flow area as is disclosed in FIG. 4 controlling the bypass accordingly may be advantageous since it e.g., enables pulse separation to be utilized in order to improve the twin scroll turbocharger device efficiency.

(27) In the embodiments referred to above; by controlling flow is meant controlling the fluid flow over a cross sectional flow area by setting a valve or like in a position from a closed to an open position, or in any partially closed or partially open position there between.

(28) The foregoing disclosure has been set forth merely to illustrate example embodiments and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the disclosure may occur to persons skilled in the art, the disclosure should be construed to include everything within the scope of the appended claims and equivalents thereof. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.