Turbocharger for an internal combustion engine

Abstract

The invention relates to a compressor for inducting an internal combustion engine, comprising an electric motor (3) for driving a first compressor wheel (4), wherein, in at least one operating state, an inlet-side, first gas flow (5a) of the internal combustion engine (1) is compressed by the compressor (2), wherein the compressor (2) comprises a first compressor path (5) for the first gas flow (5a) and a second compressor path (6) for a second gas flow (6a), wherein the second gas flow (6a), in particular, in at least one operating state, opens into an exhaust gas flow (8) of the internal combustion engine (1) as a secondary air flow (6a).

Claims

1. Compressor for inducting an internal combustion engine, comprising: an electric motor (3) for driving a first compressor wheel (4), wherein, in at least one operating state, an inlet-side, first gas flow (5a) of the internal combustion engine (1) is compressed by the compressor (2), characterised in that the compressor (2) comprises a first compressor path (5) for the first gas flow (5a) and a second compressor path (6) for a second gas flow (6a), wherein the second gas flow (6a), in particular, in the at least one operating state as a secondary air flow (6a), opens into an exhaust gas flow (8) of the internal combustion engine (1) upstream of a device for the post-treatment (9) of exhaust gas.

2. Compressor according to claim 1, characterised in that the first compressor path (5) is operated via the first compressor wheel (4), and the second compressor path (6) is operated via a second compressor wheel (11), wherein the compressor wheels (4, 11), in particular, are arranged on a common drive shaft (12).

3. Compressor according to claim 2, characterised in that the compressor wheels (4, 11) each have an axially aligned gas supply (13, 14), wherein the compressor wheels (4, 11) are oriented in opposition relative to the gas supply (13, 14).

4. Compressor according to claim 2, characterised in that the compressor wheels (4, 11) each have an axially aligned gas supply (13, 14), wherein the compressor wheels (4, 11) are oriented in the same direction in relation to the gas supply (13, 14).

5. Compressor according to claim 2, characterised in that the two compressor wheels (4, 11) are arranged on the same side of the electric motor (3).

6. Compressor according to claim 2, characterised in that the electric motor (3) is arranged between the two compressor wheels (4, 11).

7. Compressor according to claim 1, characterised in that the two gas flows (5a, 6a) are formed as different branches of a multi-port compressor housing (15′).

8. Compressor according to claim 1, wherein the device for the post-treatment (9) of exhaust gas is a catalytic converter.

9. Compressor according to claim 1, characterised in that the compressor (2) is arranged in a gas system of the internal combustion engine (1) in addition to an exhaust gas turbocharger (10), in particular on an air side in series upstream or downstream of the exhaust gas turbocharger (10).

10. Compressor according to claim 9, characterised in that the second compressor path (6) opens into an exhaust gas flow (8) of the internal combustion engine (1) upstream or downstream of the exhaust gas turbocharger.

11. Compressor according to claim 1, characterised in that, in another operating state, the second gas flow (6a) and the first gas flow (5a) are guided together.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a functional diagram of a compressor according to the invention in a gas system of an internal combustion engine.

(2) FIG. 2 shows a spatial view of a first exemplary embodiment of the compressor from FIG. 1.

(3) FIG. 3 shows a sectional view of the compressor from FIG. 2 along a shaft axis.

(4) FIG. 4 shows a spatial view of a second exemplary embodiment of the compressor from FIG. 1.

(5) FIG. 5 shows a sectional view of the compressor from FIG. 4 along a shaft axis.

(6) FIG. 6 shows a spatial view of a third exemplary embodiment of the compressor from FIG. 1.

(7) FIG. 7 shows a sectional view of the compressor from FIG. 6 along a shaft axis.

(8) FIG. 8 shows a spatial view of a fourth exemplary embodiment of the compressor from FIG. 1.

(9) FIG. 9 shows a further functional diagram of a compressor according to the invention in a gas system of an internal combustion engine.

DETAILED DESCRIPTION

(10) The functional diagram shown in FIG. 1 shows an internal combustion engine 1 of a passenger vehicle. A gas system of the internal combustion engine comprises a compressor 2, which is driven via an electric motor 3.

(11) The electric motor 3 drives a first compressor wheel 4 (see also FIG. 3, FIG. 6 and FIG. 7), by means of which an inlet-side, first gas flow 5a of the internal combustion engine 1 is compressed by the compressor 2 in a regular operating state of the internal combustion engine.

(12) The compressor 2 according to the invention comprises a first compressor path 5 for the first gas flow 5a and a second compressor path 6 for a second gas flow 6a. The second gas flow 6a opens into an exhaust gas flow 8 of the internal combustion engine 1, at least in a first operating state, as a secondary air flow (SLS) 7.

(13) In doing so, a quick heating of a device for the post-treatment 9 of exhaust gas, e.g. of a catalytic converter 9 for exhaust gas cleaning, is achieved in the event of a cold start of the internal combustion engine 1. Here, the second compressor path 6 fulfils the function of a common secondary air system, wherein a separate secondary pump is not needed.

(14) In principle, the electrically driven compressor can, in the context of the invention, be designed for permanent operation. With such a design, the compressor can be present as the only compressor in a gas system of the internal combustion engine. Yet in the case of all of the exemplary embodiments described according to FIG. 1 to FIG. 9, the compressor is provided as an additional component to an exhaust gas turbocharger 10. In this configuration, the electrically driven compressor 2 is also referred to as an “E-booster”. Here, the electrically driven compressor 2 primarily has the function of ensuring a quickly reacting, transient compression of the gas flow 5a, for example during acceleration processes of the internal combustion engine 1. The electrically driven compressor 2 according to the invention thus integrates the function of an E-booster and a secondary air pump.

(15) The compressors 2 described in the present case are compressors 2 for internal combustion engines of motor vehicles, preferably passenger vehicles.

(16) In a first concrete embodiment of a compressor 2 according to the invention according to FIG. 2 and FIG. 3, it is provided that the first compressor path 5 is operated via a first compressor wheel 4, and the second compressor path 6 is operated via a second compressor wheel 11. Here, the compressor wheels 4, 11 are arranged on a common drive shaft 12. A particularly individual design of mass flows and pressure ratios is thereby made possible for the two gas flows 5a, 6a.

(17) As can be seen in FIG. 3, the compressor wheels 4, 11 here each have a gas supply 13, 14 aligned axially or in parallel to an axis A of the drive shaft 12, wherein the compressor wheels 4, 11 are oriented in opposition relative to to the gas supply 13, 14. In doing so, a compact construction is made possible, in which the rotating mass of the two compressor wheels 4, 11, in particular, is concentrated via a short axial length.

(18) Here, a housing 15 of the compressor 2 has a first concentric inlet chamber 13 parallel to the axis A as the gas supply, via which the gas of the first gas flow 5a is guided onto the first compressor wheel 4.

(19) A line 16 is guided past a first volute 17 of the first compressor path 5 to a second inlet chamber 14 of the second compressor path 6. The second gas flow 6a enters the second inlet chamber 14 from the line 16 as the gas supply and, therein, flows in the axial direction in opposition to the first gas flow 5a onto the second compressor wheel 11. The second gas flow 6a is conveyed through the second compressor wheel 11 into a second volute 18.

(20) In particular, the sectional view FIG. 3 shows that the compressor wheels 4, 11 are arranged in opposition and lie with their respective rear sides towards one another.

(21) There is a pivot bearing 19 between the two compressor wheels 4, 11 on a substantially disc-shaped base plate 20 of the compressor 2, said base plate extending perpendicularly to the axis A. A first housing part 21 and a second housing part 22 respectively form the volutes 17, 18 of the two compressor paths 5, 6. Ends of the volutes 17, 18 are respectively connected to corresponding lines (not depicted) for conveying the compressed gas flows. In the case of the first exemplary embodiment, the two compressor wheels 4, 11 and compressor paths 5, 6 are arranged on the same side of the electric motor 3.

(22) The second exemplary embodiment of a compressor according to the invention according to FIG. 4 and FIG. 5 differs from the first exemplary embodiment in that the two compressor wheels 4, 11 of the gas supply 13, 14 are oriented in the same direction. Here, a distribution of the rotating masses takes place across a greater axial length.

(23) Corresponding to this construction, the second inlet chamber 14 is arranged in the axial direction between the compressor wheels 4, 11. The first inlet chamber 13 for the greater first gas flow 5a is, as in the first example, on a front end of the housing 15.

(24) As far is reasonable, functionally identical components of the second exemplary embodiment have been provided with the same reference numerals as in the first exemplary embodiment.

(25) In a third exemplary embodiment according to the invention according to FIGS. 6 and 7, the electric motor 3 is arranged between the two compressor wheels 4, 11. A particularly good and symmetrical support of the emerging rotational acceleration forces can hereby be achieved by corresponding pivot bearings.

(26) Here, the shaft 12 completely engages through the electric motor 3 and protrudes on each of its ends beyond one of the respective compressor wheels 4, 11 for mounting. The two gas flows 5a, 6a are supplied in opposition to each other in an axial direction. To do so, a central gas supply 23 branches into a line 24 of the first gas flow 5a and the line 16 of the second gas flow 6a. The lines 16, 24 then each comprise a deflection by 180°, such that the opening aligned in opposition into the respective inlet chambers 13, 14 takes place (see FIG. 6 and FIG. 7).

(27) In a fourth exemplary embodiment according to the invention according to FIG. 8, the two gas flows 5a, 6a are formed as different branches of a multi-port compressor housing 15′. Various combinations of mass flows and pressure ratios can hereby be generated in a simple manner, wherein, advantageously, only one compressor wheel 4 (not depicted in FIG. 8) is necessary. The electric motor is not depicted in FIG. 8, yet, as in the case of the exemplary embodiments according to FIG. 2 to FIG. 5, it is flanged laterally on the housing 15′.

(28) All of the embodiments described above of compressors 2 according to the invention can each be used in an arrangement or a gas system according to one of the functional diagrams according to FIG. 1 or FIG. 9.

(29) In each of the gas systems according to FIG. 1 and FIG. 9, in at least one operating state, the second gas flow 6a of the second compressor path 6 opens into an exhaust gas flow 8 of the internal combustion engine 1 via a line upstream of a device for the post-treatment 9 of the exhaust gas, presently a catalytic converter. The exhaust gas post-treatment 9 of the catalytic converter 9 can hereby be quickly brought to an operating temperature by means of an exothermic reaction of the second gas flow 6a, e.g. with unburnt fuel.

(30) The compressor 2 is arranged in the gas systems according to FIG. 1 and FIG. 9 of the internal combustion engine 1 in addition to the exhaust gas turbocharger 10. The compressor is arranged on the air side serially downstream of the exhaust gas turbocharger 10. Here, the exhaust gas turbocharger in stationary operation can extensively or completely take on fresh air induction, wherein the electrically driven compressor 2 is switched on as needed as the additional compressor steps. To so do, a bypass line 26 that can be switched by means of a valve 25 is provided, through which the compressor 2 is completely bypassed in the event of not being used. The valve 25 can be formed as a switching valve or as an adjustable restrictor valve.

(31) The second compressor path 6 and the second gas flow 6a open upstream of the exhaust gas turbocharger 10 or its turbines into the exhaust gas flow of the internal combustion engine 1. The exhaust gas turbocharger 10 can presently be controlled via a bypass valve 27 on the turbine side in terms of its output.

(32) An adjustable restrictor valve 28 is additionally integrated into the total gas flow leading to the internal combustion engine 1. According to need, the gas supply of the internal combustion engine 1 can hereby be restricted in general. Depending on the operating state, the conveying amount in the second compressor path 6 can be influenced by the restrictor valve 28 by retroactive effect.

(33) In the pressure side second gas flow 6a, in each of the functional diagrams according to FIG. 1, FIG. 9, a valve 29, 30 is provided in order to interrupt the secondary air supply to the exhaust gas flow 8 as needed.

(34) In the case of the first functional diagram according to FIG. 1, it is a simple, switchable blocking valve 29. Depending on the requirements, the blocking valve can also be formed as an adjustable restrictor valve set. When the blocking valve 29 is open, the gas or the fresh air of the second compressor path 6 flows into the exhaust gas flow 8. This switching position takes place, in particular, in the event of a cold start to quickly warm up the device for the exhaust gas post-treatment 9. With an internal combustion engine 1 that is warm from operation, the valve 29 is closed and the secondary air flow is interrupted. Here, the second compressor wheel 11 acts in opposition to a blocked line branch.

(35) In the variant of a gas system according to FIG. 9, the valve 30 is formed as a multi-port valve, presently as a 2/3-port valve. In a first switching position, the second gas flow 6a, as in the functional diagram according to FIG. 1, is led into the exhaust gas flow 8. In the warm operating state, in contrast, a different switching position is chosen, in which the second gas flow 6a and the first gas flow 5a are guided together. To do so, a connection line 31 is provided between the valve 30 and the pressure side first gas flow 5a. Frictional losses of the second compressor path 6 are hereby avoided.

(36) Yet in alternative functional diagrams not shown in the figures, the second compressor path 6 can also be led into the atmosphere when not in use or can be used for a different purpose with the internal combustion engine of vehicle systems.

LIST OF REFERENCE NUMERALS

(37) 1 Internal combustion engine

(38) 2 Compressor

(39) 3 Electric motor

(40) 4 First compressor wheel

(41) 5 First compressor path

(42) 5a First gas flow

(43) 6 Second compressor path

(44) 6a Second gas flow

(45) 7 Secondary air flow

(46) 8 Exhaust gas flow

(47) 9 Device for the post-treatment of exhaust gas, catalytic converter

(48) 10 Exhaust gas turbocharger

(49) 11 Second compressor wheel

(50) 12 Drive shaft

(51) 13 First inlet chamber, first gas supply

(52) 14 Second inlet chamber, second gas supply

(53) 15 Housing of the compressor

(54) 15′ Multi-port compressor housing

(55) 16 Line of the second gas flow

(56) 17 First volute

(57) 18 Second volute

(58) 19 Pivot bearing

(59) 20 Base plate

(60) 21 First housing part

(61) 22 Second housing part

(62) 23 Central gas supply

(63) 24 Line of the first gas flow

(64) 25 Valve

(65) 26 Bypass line

(66) 27 Bypass valve turbocharger

(67) 28 Restrictor valve

(68) 29 Valve, variant blocking valve or restrictor valve

(69) 30 Valve, variant multi-port valve, 3/2-port valve

(70) 31 Connection line

(71) A Axis of the drive shaft