Supercharging unit for an internal combustion engine, and internal combustion engine

Abstract

A supercharging unit for an internal combustion engine has a high-pressure turbine which drives a high-pressure compressor so as to perform a rotational movement about a first axis and through which exhaust gas of the internal combustion engine flows, and having a low-pressure turbine which drives a low-pressure compressor so as to perform a rotational movement about a second axis and through which exhaust gas flows. The high-pressure turbine is arranged rotationally conjointly on a first shaft, and the high-pressure compressor is arranged rotationally conjointly on a second shaft, wherein the first and the second shaft are arranged parallel to one another and are arranged offset with respect to one another, wherein the first and the second shaft are mechanically operatively connected to one another such that the high-pressure compressor can be driven by the high-pressure turbine.

Claims

1. A supercharging unit for an internal combustion engine, comprising: a high pressure turbine which drives a high pressure compressor to perform a rotational movement about a first axis and through which exhaust gas of the internal combustion engine flows; and a low pressure turbine which drives a low pressure compressor to perform a rotational movement about a second axis and through which exhaust gas flows; wherein the high pressure turbine is arranged on a first shaft having a first longitudinal axis, and the high pressure compressor is arranged on a second shaft having a second longitudinal axis, the first shaft and the second shaft being arranged parallel relative to each other and, viewed in a direction perpendicular to the longitudinal axes of said first shaft and said second shaft, are arranged offset with respect to one another, the first shaft and the second shaft being mechanically operatively connected to one another so that the high pressure compressor can be driven by the high pressure turbine.

2. The supercharging unit according to claim 1, wherein the first axis and the second axis are arranged at an angle relative to each other of between 80° and 20°.

3. The supercharging unit according to claim 2, wherein the first axis and the second axis are arranged at an angle relative to each other of approximately 90°.

4. The supercharging unit according claim 1, wherein the low pressure compressor and the low pressure turbine are mounted rotationally conjointly on a common third shaft.

5. The supercharging unit according to claim 1, wherein the first shaft and the second shaft are mechanically operatively connected through a gear drive.

6. The supercharging unit according to claim 5, wherein the gear drive includes a first gear arranged on the first shaft; a second gear arranged on the second shaft; and at least one third gear, wherein the first gear is operatively connected with the second gear through the at least one third gear, and wherein the third gear is mounted on a fourth shaft.

7. The supercharging unit according to claim 6, wherein a drive unit can be operatively connected with the fourth shaft for enabling a drive torque from the drive unit to be introduced into the gear drive.

8. The supercharging unit according to claim 7, wherein the drive unit is configured as an electric motor.

9. The supercharging unit according to claim 7, wherein the drive unit includes a drive shaft which can be brought into operative connection with the fourth shaft with the assistance of a clutch.

10. The supercharging unit according to claim 9, wherein the drive unit is configured as an electric motor.

11. The supercharging unit according to claim 1, further including a valve configured for allowing a flow path for the exhaust gas flowing from the internal combustion engine to the low pressure turbine to be opened, thereby allowing exhaust gas to at least partially bypass the high pressure turbine.

12. The supercharging unit according to claim 11, wherein the valve is an adjustable valve.

13. The supercharging unit according to claim 1, further including a drive unit for generating a torque which can be operatively connected with the second shaft so that the high pressure compressor can be driven using the torque produced by the drive unit.

14. The supercharging unit according to claim 1, wherein the high pressure compressor and the low pressure compressor are arranged relative to each other so that a straight flow path for charging air is created therebetween.

15. The supercharging unit according to claim 1, wherein the high pressure turbine and the low pressure turbine are arranged relative to each other so that a straight flow path for exhaust gas is created therebetween.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawing, wherein:

(2) The sole FIGURE shown in FIG. 1 is a schematic illustration of a design example of a supercharging unit of the present invention.

(3) Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates an embodiment of the invention and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

(4) FIG. 1 is a schematic illustration of a supercharging unit 1 which includes a high pressure compressor 3 which can be driven by a high pressure turbine 5 to perform a rotational movement around a first axis A.sub.1.

(5) Moreover, a low pressure compressor 7 is provided which can be driven by a low pressure turbine 9 to perform a rotational movement around a second axis A.sub.2.

(6) Exhaust gas flowing from an internal combustion engine which is not illustrated here—as illustrated by an arrow P.sub.1—is first supplied to high pressure turbine 5 through which it flows, thereby powering high pressure turbine 5. From there is directed on, along a path P.sub.2 and is supplied to low pressure turbine 9 through which it flows, thereby powering it. From there it flows—as illustrated schematically by an arrow P.sub.3—to an exhaust gas system which is not illustrated and not discussed here in further detail. High pressure turbine 5 and low pressure turbine 9 are therefore series connected, viewed in flow direction of the exhaust gas.

(7) Charging air for the internal combustion engine flows initially—as schematically indicated by an arrow P.sub.4—into low pressure compressor 7 where it is compressed in a first stage. Arrow P.sub.5 illustrates schematically that the pre-compressed charging air flows on from low pressure compressor 7 to high pressure compressor 3. There, it is further compressed in a second stage and finally—as illustrated schematically by arrow P.sub.6—is directed to the internal combustion engine.

(8) Overall, the energy of the exhaust gas flow is being utilized in an already known manner in order to compress the charging air for the internal combustion engine.

(9) High pressure turbine 5 is arranged rotationally conjointly on a first shaft 11. High pressure compressor 3 is arranged rotationally conjointly on a second shaft 13. In the illustrated design example, first shaft 11 and second shaft 13 are mechanically operatively connected with each other through a gear drive 15. If therefore exhaust gas flows through high pressure turbine 5, first shaft 11 will be driven and in turn then drives second shaft 13 via gear drive 15, so that high pressure compressor 3 is thereby also being driven.

(10) It is shown that first shaft 11 and second shaft 13 are aligned parallel relative to each other. Each have a longitudinal axis whereby in this case the longitudinal axis of second shaft 13 coincides with first axis A.sub.1. It is shown that shafts 11, 13—viewed in a direction perpendicular to their longitudinal axes—are arranged offset to one another.

(11) Low pressure compressor 7 and low pressure turbine 9 are mounted rotationally conjointly on a common third shaft 17. They are therefore directly mechanically operatively connected with each other through third shaft 17, so that low pressure compressor 7 is driven to a rotational movement when exhaust gas flows through low pressure turbine 9 and moves low pressure turbine 9 to perform a rotational movement about second axis A.sub.2. Third shaft 17 includes a rotational axis which in this case coincides with second axis A.sub.2.

(12) It is shown that first axis A.sub.1 and second axis A.sub.2 in the illustrated design example are arranged perpendicular relative to each other. Therefore, third shaft 17 on the one hand and first and second shafts 11, 13 on the other hand are also arranged perpendicular relative to each other. Third shaft 17 is thereby arranged virtually transversely above first shaft 11 and second shaft 13, wherein low pressure compressor 7 is arranged above high pressure compressor 3, and whereby moreover low pressure turbine 9 is arranged above high pressure turbine 5.

(13) In this case the term “above” relates to the illustration according to the drawing. It is obviously possible that in a specific implementation low pressure compressor 7—viewed in vertical direction—is arranged above high pressure compressor 3 whereby moreover low pressure turbine 9 is arranged above high pressure turbine 5. In another design example it is however also possible that low pressure compressor 7 is arranged beside high pressure compressor 3, whereby low pressure turbine 9 is arranged beside high pressure turbine 5. Also an arrangement offset in two directions—viewed in the direction of one axis which is positioned perpendicular in the image plane of the drawing and in the image plane as illustrated in the drawing—between low pressure compressor 7 and low pressure turbine 9, on the one hand and high pressure compressor 3 and high pressure turbine 5 on the other hand is possible. The illustration according to the only drawing therefore is consistent preferably with a projection onto the image plane, whereby charging unit 1 is depicted from the side or in another design example preferably from the top or also from the bottom.

(14) The arrangement according to FIG. 1 can be favorable, because the resulting positioning of shafts 11, 13, 17 as well as that of gear drive 15 along the four sides of a rectangle allows for an especially compact, nested arrangement of charging unit 1. Moreover, the flow paths between high pressure turbine 5 and low pressure turbine 9 on the one hand, and between low pressure compressor 7 and high pressure compressor 3 on the other hand are being shortened and are arranged especially simply without superfluous redirections and with low pressure losses.

(15) Gear drive 15 includes a first gear 19 which is arranged rotationally conjointly on first shaft 11, a second gear 21 which is arranged rotationally conjointly on second shaft 13, and a third gear 23. First gear 19 is thereby in operative connection with second gear 21, enabled by third gear 23. First gear 19 thereby interacts with third gear 23 so that same is rotationally driven when high pressure turbine 5 is driven by exhaust gas. Third gear 23 in turn interacts with second gear 21, so that second gear 21 is driven when third gear 23 is driven. In the design example illustrated in the drawing gears 19, 21, 23 are depicted in the same size, so that in this respect a 1:1 conversion of the rotational movement of the high pressure turbine into a rotational movement of the high pressure compressor occurs. It is possible to vary the diameters of gears 19, 21, 23 relative to each other, in order to implement a step-up or gear reduction between the rotational movement of high pressure turbine 5 on the one hand and high pressure compressor 3 on the other hand.

(16) It is also possible in one design example that first gear 19 interacts directly with second gear 21 without a third gear 23 being provided. It is also possible that in one design example more than one third gear 23 is provided, wherein in particular a gearbox can be provided between first gear 19 and second gear 21.

(17) Third gear 23 is hereby arranged rotationally conjointly on a fourth shaft 25.

(18) A drive unit 27 is provided which may be in the embodiment of an electric motor and which includes a drive shaft 29. This can be brought into operative connectivity with fourth shaft 25 via a clutch 31. It is therein possible to introduce an additional torque, generated by drive unit 27 into gear drive 15 and in particular into third gear 23 in order to support high pressure turbine 5 or respectively to drive high pressure compressor 3. This is especially preferred for bridging a turbo-lag at low rotational speeds of the internal combustion engine.

(19) It is provided that drive unit 27 and preferably also clutch 21 are controllable through a motor controller, so that drive unit 27 can be activated and be operationally connected via clutch 31 with gear 15 when the internal combustion engine reaches an operating point at which additional drive power should be introduced into gear drive 15. Vice versa it is possible that clutch 31 is opened in particular through the motor controller, whereby at the same time preferably drive unit 27 is deactivated, when the internal combustion engine reaches an operating point at which no additional drive power should be introduced into gear drive 15. If the mechanical operative connection between fourth shaft 25 and drive unit 27 is then disengaged via clutch 31 it need not be dragged along by high pressure turbine 5, but instead the drive power provided by it can rather be supplied completely to high pressure compressor 3.

(20) Charging unit 1 can also include a valve 33 which can also be controlled by a motor controller in order to open or close a flow path 35 or respectively preferably vary it relative to a throughput cross section, whereby high pressure turbine 5 can be bypassed via flow path 35. Valve 33 is also referred to as a so-called turbine-bypass. Depending on an operating point of the internal combustion engine the entire exhaust gas stream can therefore preferably be supplied to high pressure turbine 5 and subsequently to low pressure turbine 9; or at least part of the exhaust gas stream or also the entire exhaust gas stream can be branched off through valve 33 into flow path 35 and can be routed directly to low pressure turbine 9 by bypassing high pressure turbine 5. Dependent on the operating point it is therefore possible to preferably continuously vary the compression output of charging unit 1.

(21) Overall it has been demonstrated that with a charging unit 1 and the internal combustion engine a compact, fluidic favorable arrangement of a high pressure and a low pressure turbine as well as of a low pressure and a high pressure compressor relative to each other is possible so that in regard to the internal combustion engine space can be saved and at the same time efficient charging can be ensured.

(22) While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.