Exhaust turbocharger with catalytic converter and hybrid vehicle

Abstract

The invention relates to an exhaust-gas turbocharger (1) integrated with a catalytic converter carrier block (3) and to a hybrid vehicle (50) with such an exhaust-gas turbocharger. The exhaust-gas turbocharger (1) has a turbine housing (21), a turbine wheel (12) and a hollow body-shaped catalytic converter carrier block (3) arranged upstream of the turbine wheel (12), which is integrated into an exhaust-gas annular channel (22) of the turbine housing (21) of the exhaust-gas turbocharger (1). By the arrangement upstream of the turbine wheel (12) and by the integration into the exhaust-gas annular channel (22) of the turbine housing, a particularly good emission value of the associated internal combustion engine (51) is achieved while at the same time a compact design form is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to an exhaust gas / turbocharger for an internal combustion engine, having a compressor and a turbine, wherein the turbine has a turbine housing with an exhaust gas input connection, an exhaust gas output connection, an exhaust gas annular channel and a turbine wheel arranged in the turbine housing. BACKGROUND

[0002] Catalytic converters are arranged in the exhaust system as close as possible to the engine in order to achieve a rapid reaching of the operating temperature of the catalytic converter and to enable it to fulfil its function even at low operating temperatures, for example in city traffic. Decisive here is the light-off temperature of the catalytic converter, that is to say the temperature at which the catalytic converter begins to reduce harmful substances.

[0003] In general, this also applies to vehicles equipped with an internal combustion engine which is supercharged by means of an exhaust gas turbocharger. In order to achieve a rapid light-off of the catalytic converter and a particularly good catalytic conversion rate, it is advantageous here to arrange the catalytic converter as close as possible to the engine outlet upstream of the turbine of the exhaust gas turbocharger in terms of exhaust gas mass flow. This applies in particular in the case of a combination of an internal combustion engine with an electric drive, for example in so-called hybrid vehicles. Here, owing to the frequent periods of time during which the internal combustion engine is stopped, the catalytic converter is repeatedly cooled and thus leads to an increase in the proportion of operating phases below the light-off temperature of the catalytic converter and thus to an unacceptable increase in harmful substance emissions. In particular in this respect, therefore, it is sought to shorten the heating time of the catalytic converter by arranging it as close as possible to the engine in terms of the flow path of the exhaust gas mass flow.

[0004] However, a catalytic converter arranged upstream of the exhaust gas turbocharger has a negative effect on the performance of the internal combustion engine, in particular in the case of transient load changes, owing to the additional volume and heat capacity. Furthermore, a catalytic converter arranged upstream of the turbine of the exhaust gas turbocharger, which is advantageous for cold-start characteristics and emissions, leads to pressure and heat losses which result in a deterioration of the response characteristics in the transient operating range and of the performance in the low-torque or low-speed range. In order to prevent an effect on the operating performance, therefore, in conventional motor vehicles it has been avoided to arrange a catalytic converter upstream of the turbocharger and the catalytic converter has therefore been arranged downstream of the turbocharger. It has been known hitherto that catalytic converters which are arranged upstream of the turbocharger, that is to say upstream of the turbine, are used only in stationary applications. In motor vehicles having an internal combustion engine or combustion engine, catalytic converters have hitherto generally been arranged downstream of the turbocharger, that is to say the negative effects on cold-start characteristics and conversion rate have been tolerated in order to avoid adverse effects on the operating performance. SUMMARY

[0005] The object of the present application is to provide an exhaust-gas turbocharger of the type mentioned at the outset, which achieves particularly low emissions of the associated internal combustion engine, and to provide a hybrid vehicle, which has the feature of particularly low emissions of harmful substances.

[0006] According to the application, this object is achieved in that a catalytic converter carrier block is integrated into the exhaust-gas annular channel of the turbine housing of the exhaust-gas turbocharger upstream of the turbine wheel of the exhaust-gas turbocharger.

[0007] Thus, as claimed in the independent claims, the teaching according to the application provides, in contrast to the above-mentioned prior art, a catalytic converter, which is arranged integrated in the turbine housing upstream of the turbine wheel of the exhaust-gas turbocharger.

[0008] The exhaust-gas turbocharger for an internal combustion engine according to the application has a compressor and a turbine, which can be flowed through by an exhaust-gas mass flow, which compressor and turbine are arranged together along a turbocharger axis, wherein the turbine has a turbine housing and a turbine wheel arranged in the turbine housing. The turbine housing has an exhaust-gas input connection, which extends axially in the direction of the turbocharger axis, and an exhaust-gas annular channel, which surrounds the turbine wheel and the exhaust-gas output connection with respect to the turbocharger axis. Here, upstream of the turbine wheel and downstream of the exhaust-gas input connection, with reference to the exhaust-gas mass flow, a hollow-body-shaped catalytic converter carrier block is integrated into the turbine housing in the exhaust-gas annular channel in such a way that the catalytic converter carrier block fills the exhaust-gas annular channel circumferentially on the periphery of the exhaust-gas annular channel and surrounds the exhaust-gas output connection together with the exhaust-gas annular channel.

[0009] It is thereby ensured that the entire exhaust-gas mass flow, which is fed into the exhaust-gas annular channel upstream of the catalytic converter carrier block, must flow through the catalytic converter carrier block before reaching the turbine wheel. Here, the exhaust-gas annular channel and the catalytic converter carrier block extend at least axially over a portion of the exhaust-gas output connection, wherein the catalytic converter carrier block, although it fills the exhaust-gas annular channel circumferentially on the periphery, does not necessarily fill the exhaust-gas annular channel over the entire axial extension of the exhaust-gas annular channel. Here, the axial extension of the catalytic converter carrier block can be dimensioned in such a way that the length of the flow path through the catalytic converter carrier block ensures a high conversion rate of harmful substances in the exhaust-gas mass flow.

[0010] The embodiments of the hollow body shape of the catalytic converter carrier block here include, for example, the shape of a straight hollow cylinder, but also, for example, the shape of a conically extending hollow cylinder, in other words a hollow truncated cone, or also other hollow body shapes which are suitable for being inserted into the exhaust gas annular channel of the turbine housing.

[0011] The hybrid vehicle according to the application has an internal combustion engine and an electric machine, characterized in that the internal combustion engine has an exhaust gas turbocharger according to the application, as explained above and below.

[0012] The design concept of the exhaust gas turbocharger and the hybrid vehicle according to the application has a series of advantages. The catalytic converter is integrated into the turbine housing, so that a corresponding space saving can be achieved. Furthermore, the entire catalytic converter volume can be arranged upstream of the turbine of the exhaust gas turbocharger, that is to say, a second catalytic converter downstream of the exhaust gas turbocharger can be dispensed with. The special construction of the turbine housing in the inflow region of the turbine wheel can also be dispensed with, since this design concept can be transferred to the catalytic converter, which realizes a corresponding inflow for the turbine. The arrangement concept of the catalytic converter according to the application, in the integrated case in the turbine housing, enables the catalytic converter to be connected directly to the exhaust gas outlet manifold of the internal combustion engine together with the exhaust gas turbocharger and thus enables the flow path length between the internal combustion engine, the catalytic converter and the turbocharger to be minimized and the energy losses on the flow path to be limited to a minimum. As a result, not only can the catalytic converter be heated up quickly to its light-off temperature with high power gain, but also an improved response behavior of the exhaust gas turbocharger can be achieved.

[0013] In the aforementioned embodiments of the exhaust gas turbocharger, the catalytic converter carrier block can be configured in the form of a so-called annular catalytic converter, which has the shape of a hollow cylinder or a hollow truncated cone, which is inserted into the exhaust gas annular channel. This contrasts with conventional solid cylindrical or solid conical catalytic converter carrier blocks. The annular shape or the hollow cylinder shape or the hollow truncated cone shape has particular advantages here, since the catalytic converter carrier block can thereby be integrated completely into the exhaust gas annular channel of the turbine housing, which surrounds the turbine wheel and the exhaust gas outlet connection. This enables a particularly compact construction of the combination of the exhaust gas turbocharger and the catalytic converter.

[0014] Furthermore, embodiments according to the application have the advantage that the catalytic converter inlet is arranged very close to the outlet of the internal combustion engine and the catalytic converter outlet is arranged very close to the turbine wheel. This can be achieved in a compact manner in particular when the catalytic converter carrier block is configured as an annular catalytic converter. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application and advantageous embodiments thereof are explained and illustrated in detail below with the aid of the drawings. Shown here is:

[0016] Figure 1 A schematic simplified view of an embodiment of an exhaust-gas turbocharger according to the application is shown in a half-section view, the exhaust-gas turbocharger having a catalytic converter carrier block integrated into the turbine housing;

[0017] Figure 2 and Figure 3 Two different embodiments of a catalytic converter carrier block are shown in simplified views;

[0018] Figure 4 A very simplified view of a hybrid vehicle according to the application is shown, the hybrid vehicle having an internal combustion engine, an electric machine and an exhaust-gas turbocharger according to the application. DETAILED DESCRIPTION

[0019] The exhaust-gas turbocharger 1 shown here has arranged next to one another along a turbocharger axis 2 (from left to right in the illustration) a compressor 30 having a compressor housing 31, a bearing assembly 10 and a turbine 20 which is flowed through by an exhaust-gas mass flow AM, the turbine having a turbine housing 21.

[0020] Arranged in the compressor housing 31 is a compressor wheel 13, and arranged in the turbine housing 21 is a turbine wheel 12. The compressor wheel 13 and the turbine wheel 12 are arranged in a rotationally fixed manner on opposite ends of a rotor shaft 14 and form, together with the rotor shaft 14, a turbocharger rotor which can be supported in a rotationally fixed manner in the bearing assembly 10 about a turbocharger axis 2 which at the same time constitutes the rotor axis of rotation and which defines the axial direction of the exhaust-gas turbocharger 1.

[0021] The turbine housing 21 has an exhaust-gas input connection 27 which extends in the axial direction along the turbocharger axis 2, an exhaust-gas output connection 28 and an exhaust-gas annular channel 22 which surrounds the turbine wheel 12 and the exhaust-gas output connection 28 with respect to the turbocharger axis 2. The exhaust-gas annular channel 22 extends in the axial direction over the exhaust-gas output connection 28 and surrounds the exhaust-gas output connection on the outer periphery thereof.

[0022] In the case of an exhaust-gas turbocharger according to the application, the exhaust-gas annular channel 22 is formed by a carrier block 40 which is integrated into the turbine housing 21 and which is formed in one piece with the turbine housing 21. Figure 1The exhaust gas mass flow AM, which is shown by the solid arrow, is the reference upstream of the turbine wheel 12 and downstream of the exhaust gas input connection 27, in the exhaust gas annular channel 22, the hollow body shaped catalytic converter carrier block 3, which can also be referred to as an annular catalytic converter, designed as a hollow cylinder, is integrated into the turbine housing 21 in such a way that it annularly fills the circumference of the exhaust gas annular channel 22 and together with the exhaust gas annular channel 22 encloses the exhaust gas output connection 28.

[0023] Figure 2 A possible shape of the hollow body shaped catalytic converter carrier block 3 is shown, namely a catalytic converter carrier block 3 configured as a straight hollow cylinder.

[0024] In Figure 3 Another possible shape of the hollow body shaped catalytic converter carrier block 3 is shown, namely a catalytic converter carrier block 3 configured as a hollow truncated cone.

[0025] According to one embodiment of the exhaust gas turbocharger 1, an intake annular channel 23 is configured upstream of the catalytic converter carrier block 3 in the exhaust gas annular channel 22, to which the exhaust gas input connection 27 is connected for feeding in the exhaust gas mass flow AM. In this embodiment, by means of the intake annular channel 23, the exhaust gas mass flow AM is fed into the exhaust gas annular channel 22 from the tangential direction and into the catalytic converter carrier block in such a way that it is distributed over the circumference of the inlet side of the catalytic converter carrier block. The intake annular channel 23 can be configured, for example, as a spiral channel with a cross section that tapers in the flow direction of the exhaust gas mass flow AM, as shown in Figure 1 This corresponds approximately to the geometry of the exhaust gas spiral / flow channel, which is commonly used in turbine housings to guide the exhaust gas in a spiral trajectory onto the inlet side 4 of the catalytic converter. This advantageously enables the exhaust gas mass flow AM to be distributed uniformly over the circumference of the inlet side 4 of the catalytic converter and to flow uniformly through the catalytic converter carrier block.

[0026] Furthermore, in this embodiment, a guide annular channel 24 is configured downstream of the catalytic converter carrier block 3 in the exhaust gas annular channel 22 for forwarding the exhaust gas mass flow AM onto the turbine wheel 12. This advantageously enables the exhaust gas mass flow AM to be distributed uniformly over the circumference of the turbine wheel 12 and to be fed into the exhaust gas annular gap 25 in such a way that it is distributed over the circumference in order to be forwarded onto the turbine wheel 12.

[0027] The flow direction and flow path of the exhaust gas mass flow AM through the turbine housing 21 and the catalytic converter carrier block 3 is indicated by the solid arrows and in the listed order by the exhaust gas input connection 27 into the intake annular channel 23 and further through the catalytic converter carrier block 3 into the guide gas annular channel 24 and from there via the exhaust gas annular gap 25 to the turbine wheel 12 and further through the flow channel 29 of the exhaust gas output connection 28 into the exhaust system of the motor vehicle, for example a hybrid vehicle 50, as shown in Figure 4

[0028] After leaving the catalytic converter carrier block 3, the purified exhaust gas mass flow AM accumulates in the guide gas annular channel 24 on the catalytic converter outlet side 5 of the catalytic converter carrier block and immediately thereafter passes through the surrounding exhaust gas annular gap 25, which is a cross-sectional constriction in the main radial direction towards the turbine wheel 12, from where the exhaust gas mass flow flows onto the turbine wheel 12 and drives the same. The exhaust gas is output from the turbine wheel 12 in the axial direction via the exhaust gas output connection 28, which has a flow channel 29, which is configured for example as an outlet diffuser with a cross section tapering in the flow direction. A connecting flange on the end of the exhaust gas output connection 28 serves for fastening on the exhaust system of the associated internal combustion engine.

[0029] According to a further embodiment, as Figure 1 Exemplarily shown, the exhaust gas turbocharger 1 has a catalytic converter carrier block 3 with a catalytic converter inlet side 4 upstream and a catalytic converter outlet side 5 downstream in the exhaust gas mass flow AM, wherein a through-flow channel 6 is provided in the catalytic converter carrier block 3, which extends between the catalytic converter inlet side 4 and the catalytic converter outlet side 5 with an axial extension component and an extension component in the circumferential direction of the hollow body-shaped catalytic converter carrier block 3 relative to the turbocharger axis 2. This results in a more or less helical extension of the flow channel 6 and in an inclined inflow direction of the exhaust gas mass flow relative to the catalytic converter inlet side 4 and an inclined outflow direction relative to the catalytic converter outlet side 5.

[0030] ​Preferably, the flow channels 6 are inclined on the catalytic converter inlet side 4 in the circumferential direction against the flow direction of the exhaust gas mass flow AM, i.e. against the helical run of the inlet annular channel 23, thereby reducing the necessary deflection of the exhaust gas mass flow upon entering the catalytic converter carrier block 3 and the associated flow losses. In the case of maintaining this inclination, the flow channels 6 helically pass through the catalytic converter carrier block 3 and, on the catalytic converter outlet side 5, give the exhaust gas mass flow AM a flow direction having a more or less large directional component in the circumferential direction of the guide annular channel 24 into the exhaust gas annular gap 25 and onto the turbine wheel 12. By this arrangement of the flow channels 6, on the one hand, the flow losses of the exhaust gas mass flow are advantageously reduced and the power gain of the turbine wheel 12 is increased, on the other hand, the flow path length through the catalytic converter carrier block 3 is thereby increased, ensuring a high conversion rate of the harmful substances in the exhaust gas mass flow AM. In other words, in this embodiment, the structure of the catalytic converter carrier block 3 serves to optimize the inflow and power gain of the turbine and to optimize the conversion rate of the harmful substances.

[0031] In another embodiment of the exhaust-gas turbocharger 1, as also shown in Figure 1 In another embodiment of the exhaust-gas turbocharger 1, as also shown in

[0032] In another embodiment of the exhaust-gas turbocharger 1, a variable flow guide 26 is arranged in an exhaust-gas annular gap 25 formed in the transition between the exhaust-gas annular channel 22 and the turbine wheel 12 downstream of the catalytic converter carrier block 3. Such a flow guide 26 of the turbine is also referred to as "variable turbine geometry" (VTG) and serves to control the exhaust gas mass flow AM towards the turbine wheel 12 and to vary the throughflow cross section of the exhaust-gas annular gap 25 in order to advantageously match the power of the turbocharger in the transient operating range of the internal combustion engine.

[0033] A further embodiment of the exhaust-gas turbocharger according to the application is characterized in that the exhaust-gas outlet connection 28 of the turbine housing 21 is designed as an outlet diffuser having flow channels 29 which expand in the flow direction of the exhaust gas mass flow AM, likewise as shown in Figure 1As shown. The annular exhaust gas passage 22 of the turbine housing, and the catalytic converter carrier block integrated therein, surround the exhaust gas outlet pipe and thus also surround the outlet diffuser. In the outlet diffuser, the exhaust gas mass flow is depressurized and advantageously reduces the exhaust gas back pressure acting on the turbine impeller outlet.

[0034] As from Figure 1 As can be seen, the features of the above-described embodiments, as well as combinations of multiple or all of these features, can also be realized in the exhaust gas turbocharger.

[0035] Integrating the catalytic converter carrier block 3, particularly in the form of an annular catalytic converter, into the turbine housing 21 of the exhaust gas turbocharger 1 according to the present invention brings a series of advantages. These advantages primarily include the close proximity of the catalytic converter to the engine's exhaust valve, resulting in faster catalytic converter response and improved cold start and restart emissions. Furthermore, compared to conventional catalytic converters, higher pressure and a better uniform temperature distribution are achieved within the catalytic converter carrier block 3, leading to a higher conversion rate of harmful substances in the exhaust gas mass flow. Additionally, a reduced thermal load is achieved on the exhaust gas turbocharger turbine. Moreover, a simple and cost-effective structural form is realized.

[0036] exist Figure 4 The image symbolically illustrates a hybrid vehicle 50 according to the invention. This hybrid vehicle has an internal combustion engine 51 and an electric motor 52, and is characterized in that the internal combustion engine 51 has an exhaust gas turbocharger 1 according to one of the foregoing embodiments. The exhaust gas turbocharger 1 is connected to the exhaust system 53 of the hybrid vehicle 50 to discharge a mass stream AM of exhaust gas purified of harmful substances.

[0037] Hybrid vehicles utilize a combination of a conventional internal combustion engine, particularly a combustion-type engine, and an electric motor. Typically, the electric drive unit is used for low loads and short distances, while the internal combustion engine is primarily used for higher loads and long distances, or as a so-called "range extender" to charge the battery. In other words, the operating range of the internal combustion engine in a hybrid vehicle is relatively small compared to a vehicle with a purely internal combustion engine drive. This means that for hybrid drive units, the torque characteristics and transient response (instantaneous response) of the internal combustion engine in the low-speed range are less important, while restart performance and emissions are more crucial.

[0038] Since the requirements on the torque behavior and the transient behavior (transient response) in the low speed range of the internal combustion engine are lower in hybrid drive devices as a result of this, it is proposed that the solution according to the application, in which a catalytic converter device is used upstream of the exhaust gas turbocharger in such a hybrid vehicle, in order to achieve particularly good results in terms of the respective emissions. The solution according to the application is therefore particularly advantageous for such hybrid vehicles, since different requirements are placed on hybrid vehicles compared to vehicles with internal combustion engines. The solution according to the application can therefore be particularly well implemented here.

[0039] List of reference signs:

[0040] 1 exhaust gas turbocharger

[0041] 2 turbocharger axis

[0042] 3 catalytic converter carrier block

[0043] 3a inner tube

[0044] 3b outer tube

[0045] 4 catalytic converter inlet side

[0046] 5 catalytic converter outlet side

[0047] 6 flow channel

[0048] 10 bearing assembly

[0049] 12 turbine wheel

[0050] 13 compressor wheel

[0051] 14 rotor shaft

[0052] 20 turbine

[0053] 21 turbine housing

[0054] 22 exhaust gas annular channel

[0055] 23 intake annular channel

[0056] 24 guide annular channel

[0057] 25 exhaust gas annular gap

[0058] 26 flow guide

[0059] 27 exhaust gas input connection

[0060] 28 exhaust gas output connection

[0061] 29 flow channel of the exhaust gas output connection

[0062] 30 compressor

[0063] 31 compressor housing

[0064] 50 hybrid vehicle

[0065] 51 internal combustion engine

[0066] 52 electric motor

[0067] 53 exhaust system

[0068] AM exhaust gas mass flow

Claims

1. An exhaust gas turbocharger (1) for an internal combustion engine (51), the exhaust gas turbocharger having a compressor (30) and a turbine (20) through which an exhaust gas mass flow (AM) can pass, the compressor and the turbine being arranged together along a turbocharger axis (2), wherein, The turbine (20) has a turbine housing (21) and a turbine impeller (12) arranged in the turbine housing (21). The turbine housing (21) has an exhaust gas inlet pipe (27), an exhaust gas outlet pipe (28), and an exhaust gas annular passage (22). The exhaust gas outlet pipe extends axially in the direction of the turbocharger axis (2). The exhaust gas annular passage surrounds the turbine impeller (12) and the exhaust gas outlet pipe (28) relative to the turbocharger axis (2). Its features are, Based on the exhaust gas mass flow (AM), a hollow catalytic converter carrier block (3) is integrated into the turbine housing (21) in the exhaust gas annular channel (22) upstream of the turbine impeller (12) and downstream of the exhaust gas inlet pipe (27), such that the catalytic converter carrier block surrounds and fills the exhaust gas annular channel (22) around the periphery of the exhaust gas annular channel (22) and together with the exhaust gas annular channel (22) surrounds the exhaust gas outlet pipe (28).

2. The exhaust gas turbocharger (1) according to claim 1, characterized in that, An intake annular channel (23) is constructed upstream of the catalytic converter carrier block (3) in the exhaust annular channel (22), and an exhaust gas inlet pipe (27) is connected to the intake annular channel to introduce exhaust gas mass flow (AM). A guide annular channel (24) is constructed downstream of the catalytic converter carrier block (3) in the exhaust annular channel (22) to transfer the exhaust gas mass flow (AM) to the turbine impeller (12).

3. The exhaust gas turbocharger (1) according to claim 1 or 2, characterized in that, The catalytic converter carrier block (3) has an upstream catalytic converter inlet side (4) and a downstream catalytic converter outlet side (5) in the exhaust gas mass flow (AM), and a through flow channel (6) extending between the catalytic converter inlet side (4) and the catalytic converter outlet side (5), the flow channel having an axial extension component relative to the turbocharger axis (2) and a circumferential extension component in the hollow catalytic converter carrier block (3).

4. The exhaust gas turbocharger (1) according to claim 1 or 2, characterized in that, The hollow-shaped catalytic converter carrier block (3) includes an inner tube and an outer tube surrounding the catalytic converter carrier block (3) on the outside, for stabilizing the catalytic converter carrier block (3).

5. The exhaust gas turbocharger according to claim 1 or 2, characterized in that, Downstream of the catalytic converter carrier block (3), in the transition between the exhaust gas annular channel (22) and the turbine impeller (12), an exhaust gas annular gap (25) is formed, and a variable guide (26) is arranged in the exhaust gas annular gap.

6. The exhaust gas turbocharger according to claim 1 or 2, characterized in that, The exhaust outlet pipe (28) is configured as an outlet diffuser having a flow channel (29) that expands along the flow direction of the exhaust mass flow (AM).

7. A hybrid vehicle (50) having an internal combustion engine (51) and an electric motor (52), characterized in that, The internal combustion engine (51) has an exhaust gas turbocharger (1) according to any one of claims 1 to 6.

Images