METHOD FOR CONTROLLING AN ELECTRIFIED TURBOCHARGER OF AN INTERNAL COMBUSTION ENGINE, AND A MOTOR VEHICLE WITH AN INTERNAL COMBUSTION ENGINE

Abstract

A method for controlling an electrical exhaust gas turbocharger of an internal combustion engine includes a measure (a), in accordance with which a load requirement placed on the internal combustion engine is monitored, and a measure (b), in accordance with which a boost mode of the electrical exhaust gas turbocharger is activated if the load requirement monitored in measure (a) exceeds a predetermined threshold value.

Claims

1. A method for controlling an electrified exhaust gas turbocharger of an internal combustion engine, in particular of a motor vehicle, the internal combustion engine including an exhaust gas flow module and an intake air flow module, the electrified exhaust gas turbocharger including an exhaust gas turbine, arranged in the exhaust gas flow module and driven by exhaust gas from the internal combustion engine, which exhaust gas turbine is connected by a drive to an electrical generator, the electrified exhaust gas turbocharger including a compressor for the compression of charge air supplied to the internal combustion engine via the intake air flow module, which compressor can be driven by an electrical motor, which is connected, or can be connected, by a drive to the generator, the electrified exhaust gas turbocharger having a boost pressure control device, in particular a wastegate valve and/or a variable turbine geometry, with which a fluid flow throttling resistance, which is encountered by the flow of the exhaust gas in the course of operation of the internal combustion engine, can be varied, the method comprising: (a) monitoring a load requirement placed on the internal combustion engine; and (b) if the load requirement monitored in measure (a) exceeds a predetermined (first) threshold value: activating a boost mode of the electrified exhaust gas turbocharger, in which the fluid flow throttling resistance is minimized with the boost pressure control device, and the electrical motor is supplied with electrical power and energy such that the compressor generates charge air at a maximum boost pressure.

2. The method according to claim 1, wherein the electrical generator is electrically connected, or can be connected, by a drive to the electrical motor via an interposed, or interposable, and chargeable, electrical energy storage system, such that the energy generated by the generator and stored in the energy storage system is available for driving the motor at a later point in time.

3. The method according to claim 2, wherein in the boost mode, the electrical power and energy for driving the electrical motor is completely drawn by the latter from the electrical energy storage system.

4. The method according to claim 1, further comprising: (c) if the load requirement monitored in measure (a) falls below a predetermined second threshold value, which is less than the first threshold value: activating a brake mode of the electrified exhaust gas turbocharger, in which the fluid flow throttling resistance is maximized with the boost pressure control device.

5. The method according to claim 4, further comprising: (d) if the load requirement monitored in measure (a) is equal to or greater than the second threshold value, and equal to or less than the first threshold value: operating the electrified exhaust gas turbocharger in a normal mode in which the fluid flow throttling resistance is maintained or varied with the controllable boost pressure control device as a function of the load requirement monitored in accordance with measure (a).

6. The method according to claim 1, wherein the activated boost mode is maintained until the load requirement monitored in accordance with measure (a) falls below a third threshold value, which is less than or equal to the first threshold value and is larger than or equal to the second threshold value.

7. The method according to claim 6, wherein if the load requirement monitored in measure (a) falls below the third threshold value, the boost mode of the electrified exhaust gas turbocharger activated in measure (b) is deactivated.

8. The method according to claim 4, wherein the electrified exhaust gas turbocharger is operated in brake mode until the load requirement monitored in accordance with measure (a) exceeds a fourth threshold value, which is larger than or equal to the second threshold value, and less than or equal to the first threshold value.

9. The method according to claim 8, wherein if the load requirement monitored in measure (a) rises above the fourth threshold value, the brake mode of the electrified exhaust gas turbocharger activated in measure (c) is deactivated.

10. The method according to claim 1, wherein in the boost mode, no electrical power and energy is produced by the electrical generator.

11. The method according to claim 4, wherein in the brake mode of the electrified exhaust gas turbocharger, an electrical load on the electrical generator connected by a drive to the exhaust gas turbine is maximized.

12. The method according to claim 1, wherein the load requirement monitored in measure (a) is a torque requirement or an acceleration requirement.

13. The method according to claim 1, wherein: the controllable boost pressure control device is formed by a variable turbine geometry with adjustable guide vanes, wherein the guide vanes can be adjusted such that the fluid flow throttling resistance alters as a function of their position; and/or the controllable boost pressure control device is formed by a wastegate valve, with which a bypass channel can be opened such that in an at least partially opened state of the wastegate valve at least some of the exhaust gas can be led past the exhaust gas turbine via the bypass channel, with a reduction in the fluid flow throttling resistance.

14. The method according to claim 1, wherein in measure (b) the boost mode is not activated in steady full load operation of the internal combustion engine, and in particular is deactivated after a predetermined period of time at the latest.

15. A vehicle comprising: an internal combustion engine, the internal combustion engine comprising: an electrified exhaust gas turbocharger; an exhaust gas flow module; and an intake air flow module, wherein the electrified exhaust gas turbocharger comprises an exhaust gas turbine arranged in the exhaust gas flow module, and driven by exhaust gas from the internal combustion engine, which exhaust gas turbine is connected by a drive to an electric generator, wherein the electrified exhaust gas turbocharger comprises a compressor for purposes of the compression of charge air supplied to the internal combustion engine via the intake air flow module, which compressor can be driven by an electrical motor, which is connected, or can be connected, by a drive to the generator, wherein the electrified exhaust gas turbocharger has a boost pressure control device, in particular a wastegate valve, and/or a variable turbine geometry, with which a fluid flow throttling resistance, which is encountered by the flow of the exhaust gas in the course of operation of the internal combustion engine, can be varied, and wherein the internal combustion engine comprises a control/regulation device (EPU) which is equipped to execute the method according to one of the preceding claims.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The disclosure will now be described with reference to the drawings wherein:

[0033] FIG. 1 shows an exemplary embodiment of a motor vehicle in accordance with the disclosure in a layout schematic,

[0034] FIG. 2 shows another exemplary embodiment of a motor vehicle in accordance with the disclosure in a layout schematic,

[0035] FIG. 3 shows a flow chart of a method in accordance with an exemplary embodiment of the disclosure, and

[0036] FIG. 4 shows a flow chart of a method in accordance with another exemplary embodiment of the disclosure.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0037] Exemplary embodiments of the disclosure are shown in the figures and are explained in more detail in the following detailed description, wherein identical reference symbols refer to identical, or similar, or functionally identical, components.

[0038] FIG. 1 illustrates a layout of a motor vehicle 30 in accordance with an exemplary embodiment of the disclosure. The motor vehicle 30 has an internal combustion engine 3 with an electrified exhaust gas turbocharger 2. The internal combustion engine 3 also comprises an exhaust gas flow module 4 and an intake air flow module 5. Exhaust gas 6 from the internal combustion engine 3 can flow through the exhaust gas flow module 4. Expediently, charge air 10 can flow through the intake air path 5, which charge air can be supplied to the internal combustion engine 3. The electrified exhaust gas turbocharger 2 has an exhaust gas turbine 7, which is arranged in the exhaust gas flow module 4 of the internal combustion engine 3. In the course of operation of the internal combustion engine 3 the exhaust gas turbine 7 is driven by exhaust gas 6 from the internal combustion engine 3. The electrified exhaust gas turbocharger 2 also comprises an electrical generator 8, which is connected by a drive to the exhaust gas turbine 7. Expediently, the electrical generator 8 is mechanically connected to the exhaust gas turbine 7. In addition, the electrified exhaust gas turbocharger 2 comprises a compressor 9 for purposes of the compression of the charge air 10, which is fed to the internal combustion engine 3 via the intake air flow module 5. In addition, the electrified exhaust gas turbocharger 2 has an electrical motor 11, which is connected by a drive to the compressor 9. The electrical motor 11 can expediently be mechanically connected by a drive to the compressor 9. The generator 8 is connected, or can be connected, not by a mechanical drive, but rather by an electrical drive, to the electrical motor 11. The electrified exhaust gas turbocharger 2 also comprises a boost pressure control device 12. With this boost pressure control device 12 a fluid flow throttling resistance 15, which is encountered by the flow of the exhaust gas 6 in the course of operation of the internal combustion engine 3, can be varied. It can be discerned that the internal combustion engine 3 also comprises a control/regulation device, an ECU. The control/regulation device, or ECU, of the internal combustion engine 3 of the motor vehicle 30, is set up/programmed to execute a method 1 in accordance with the disclosure for the control of the electrified exhaust gas turbocharger 2 of the internal combustion engine 3 of the motor vehicle 30.

[0039] In accordance with the exemplary embodiment shown in FIG. 1, the boost pressure control device 12 of the electrified exhaust gas turbocharger 2 is designed as a wastegate valve 13. With the wastegate valve 13, a bypass channel 23 can be opened up in terms of fluid flow, so that in a partially open state of the wastegate valve 13, at least some of the exhaust gas 6 can be led past the exhaust gas turbine 7 via the bypass channel 23. This is accompanied by a reduction of the fluid flow throttling resistance 15, which is encountered by the flow of the exhaust gas 6 in the course of operation of the internal combustion engine 3.

[0040] FIG. 2 illustrates another exemplary embodiment of a motor vehicle 30 in accordance with the disclosure, with an internal combustion engine 3 comprising an electrified exhaust gas turbocharger 2. The exemplary embodiment shown in FIG. 2 differs from that in FIG. 1 in that the boost pressure control device 12 is formed by a variable turbine geometry 14. The variable turbine geometry 14 has adjustable guide vanes. Here the adjustable guide vanes of the variable turbine geometry 14 can be adjusted such that the fluid flow throttling resistance 15 alters as a function of their position. Expediently the guide vanes of the variable turbine geometry 14 can be adjusted such that their adjustment is accompanied by a change in a flow cross section of the exhaust gas 6 flowing through the variable turbine geometry 14, which causes a change in the throttling resistance 15.

[0041] FIGS. 1 and 2 also show that the temperature of the charge air 10 that can be led through the intake air flow module 5 can be altered with a charge air cooler 26 located in the intake air flow module 5. In addition, an exhaust gas catalytic converter 27 can be present in the exhaust gas line 4 for the aftertreatment of the exhaust gas 6. It can also be discerned that the electrical generator 8 is electrically connected, or can be connected, by a drive to the electrical motor 11 via an intermediate, or what can be an intermediate, electrical energy storage system 19, so that the energy generated by the generator 8 and stored in the energy storage system 19 is available for purposes of driving the motor 11 at a later point in time. The electrical motor 11 and the electrical generator 8 can be electrically connected to the electrical energy storage system 19 with power electronics 28. The power electronics 28 can comprise an electrical converter. The power electronics 28 can comprise an AC-DC/DC-AC converter. The power electronics 28 can be equipped to distribute an electrical load to the electrical components connected to the latter.

[0042] FIG. 3 illustrates in an exemplary flow chart the sequence of a method 1 in accordance with the disclosure for the control of the electrified exhaust gas turbocharger 2 shown in FIGS. 1 and 2.

[0043] The method 1 comprises a measure a), in accordance with which a load requirement 16 placed on the internal combustion engine 3 is monitored. Typically, such a load requirement 16 for the internal combustion engine 3 is specified by the driver of a motor vehicle 30 comprising the internal combustion engine 3. Expediently, the load requirement 16 monitored in measure a) can be a torque requirement or an acceleration requirement.

[0044] The method 1 also comprises a measure b), which is undertaken if the load requirement 16 monitored in measure a) exceeds a predetermined first threshold value 17. If this condition is fulfilled, a boost mode 18 of the electrified exhaust gas turbocharger 2 is activated in accordance with measure b). In the boost mode 18 of the electrified exhaust gas turbocharger 2, the fluid flow throttling resistance 15, which is encountered by the flow of the exhaust gas 6 in the course of operation of the internal combustion engine 3, is minimized with the boost pressure control device 12. In the case in which the boost pressure control device 12 comprises a wastegate valve 13, this is achieved in that with the wastegate valve 13 a bypass channel 23 is connected, in terms of fluid flow, in parallel with the exhaust gas turbine 7; this connection is accompanied by an increase in a flow cross section of the flow of the exhaust gas 6, reducing the throttling resistance 15. In the case in which the boost pressure control device 12 has a variable turbine geometry 14, the minimizing of the throttling resistance 15 is achieved by moving guide vanes of the variable turbine geometry 14 into a maximum open position, in which a maximum flow cross section is achieved for the flow of the exhaust gas 6, and thus a minimum throttling resistance 15. At the same time, in the boost mode 18 the electrical motor 11 is supplied with electrical power and energy such that the compressor 9, connected by a drive to the electrical motor 11, generates charge air 10 with a maximum boost pressure. In the boost mode 18, the electrical power and energy for purposes of driving the electrical motor 11 is essentially drawn completely from the electrical energy storage system 14.

[0045] FIG. 4 shows another exemplary embodiment of a method 1 in accordance with the disclosure in a flow chart. It can be discerned that the method additionally comprises a measure c). The said measure c) ensures that if the load requirement 16 monitored in measure a) falls below a predetermined second threshold value 20, which is less than the first threshold value 17, a brake mode 21 of the electrified exhaust gas turbocharger 2 is activated. In this brake mode 21 of the electrified exhaust turbocharger 2, the fluid flow throttling resistance 15 is maximized with the boost pressure control device 12.

[0046] FIGS. 3 and 4 also show that the method 1 comprises a further measure d). In accordance with measure d), the electrified exhaust gas turbocharger 2 is operated in a normal mode 22, if the load requirement 16 monitored in measure a) is equal to or greater than the second threshold value 20, and equal to or less than the first threshold value 17. In the normal mode 22 of the electrified exhaust turbocharger 2, the fluid flow throttling resistance 15 is maintained or varied with the controllable boost pressure control device 12 as a function of the load requirement 16 monitored in measure a).

[0047] It also follows from FIG. 3 that the activated boost mode 18 is maintained until the load requirement 16 monitored in measure a) falls below a third threshold value 24. This third threshold value 24 is less than or equal to the first threshold value 17, and greater than or equal to the second threshold value 20. Here the boost mode 18 of the electrified exhaust gas turbocharger 2 activated in measure b) is deactivated, if the load requirement 16 monitored in measure a) falls below the third threshold value 24.

[0048] It can be discerned from FIG. 4 that the electrified exhaust gas turbocharger 2 is operated in brake mode 21 until the load requirement 16 monitored in measure a) exceeds a fourth threshold value 25. The fourth threshold value 25 is greater than or equal to the second threshold value 20, and less than or equal to the first threshold value 17. The brake mode 21 of the electrified exhaust gas turbocharger 22 activated in measure c) is deactivated if the load requirement 16 monitored in measure a) exceeds the fourth threshold value 25.

[0049] In the boost mode 18, the electrical generator 8 produces essentially no electrical power or energy. This is expediently achieved by interrupting an electrical connection to electrical loads electrically connected to the generator 8, and the electrical drive connection to the electrical motor 11. This means that expediently the electrical generator 8 is not loaded electrically in the boost mode 18. In contrast, in the brake mode 18 of the electrified exhaust gas turbocharger 2, an electrical load on the electrical generator 8, connected by a drive to the exhaust gas turbine 7, is maximized. In measure b), the boost mode 18 is not activated in steady full load operation of the internal combustion engine 30. To this end, the boost mode 18 can be again deactivated after a predetermined period of time at the latest.

[0050] It is understood that the foregoing description is that of the exemplary embodiments of the disclosure and that various changes and modifications may be made thereto without departing from the spirit and scope of the disclosure as defined in the appended claims.