DE102014216103A1 - Supercharged internal combustion engine with exhaust gas recirculation and method for operating such an internal combustion engine - Google Patents

Abstract

The invention relates to a supercharged internal combustion engine having - an intake system (1) for supplying charge air, - an exhaust gas removal system for discharging exhaust gas, - at least one exhaust gas turbocharger comprising a turbine arranged in the Abgasabführsystem and a in the intake system (1) arranged compressor (2) wherein the compressor (2) is equipped with at least one impeller mounted in a compressor housing (2c) on a rotatable shaft, and an exhaust gas recirculation comprising a recirculation line branching from the exhaust system downstream of the turbine of the at least one exhaust gas turbocharger and upstream of the at least one compressor impeller under formation of a node in the intake system (1) opens. It is intended to provide an internal combustion engine of the type mentioned with which high exhaust gas recirculation rates can be realized by means of low-pressure EGR and with which, in particular, the formation of condensate in the context of low-pressure EGR can be counteracted. This is achieved by an internal combustion engine, which is characterized in that - the intake system (1) upstream of the compressor housing (2c) and downstream of the node (5c) is equipped with a heater (3).

Description

• – einem Ansaugsystem zum Zuführen von Ladeluft,
• – einem Ansaugsystem zum Zuführen von Ladeluft,
• – einem Abgasabführsystem zum Abführen von Abgas,
• – mindestens einem Abgasturbolader, der eine im Abgasabführsystem angeordnete Turbine und einen im Ansaugsystem angeordneten Verdichter umfasst, wobei der Verdichter mit mindestens einem in einem Verdichtergehäuse auf einer drehbaren Welle gelagerten Laufrad ausgestattet ist, und
• – einer Abgasrückführung umfassend eine Rückführleitung, die stromabwärts der Turbine des mindestens einen Abgasturboladers vom Abgasabführsystem abzweigt und stromaufwärts des mindestens einen Verdichterlaufrades unter Ausbildung eines Knotenpunktes in das Ansaugsystem mündet.

The invention relates to a supercharged internal combustion engine with

• An intake system for supplying charge air,
• An intake system for supplying charge air,
• An exhaust gas removal system for removing exhaust gas,
• - At least one exhaust gas turbocharger, which comprises a turbine arranged in the Abgasabführsystem and a compressor arranged in the intake system, wherein the compressor is equipped with at least one mounted in a compressor housing on a rotatable shaft impeller, and
• An exhaust gas recirculation system comprising a return line, which branches off from the exhaust gas removal system downstream of the turbine of the at least one exhaust gas turbocharger and opens into the intake system upstream of the at least one compressor impeller, forming a junction point.

Furthermore, the invention relates to a method for operating such an internal combustion engine.

An internal combustion engine of the type mentioned is used as a motor vehicle drive. In the context of the present invention, the term internal combustion engine includes diesel engines and gasoline engines, but also hybrid internal combustion engines that use a hybrid combustion process, as well as hybrid drives, which in addition to the internal combustion engine include an electric motor that can be connected to the engine, which receives power from the internal combustion engine or as switchable auxiliary drive additionally delivers power.

In recent years, there has been a trend toward small, supercharged engines, with supercharging primarily a method of increasing performance by compressing the air needed for the engine combustion process. The economic importance of these engines for the automotive industry continues to increase.

Frequently, an exhaust gas turbocharger is used for charging, in which a compressor and a turbine are arranged on the same shaft. The hot exhaust stream is supplied to the turbine and relaxes with energy release in the turbine, causing the shaft to rotate. The energy emitted by the exhaust gas flow to the turbine and finally to the shaft is used to drive the compressor, which is also arranged on the shaft. The compressor conveys and compresses the charge air supplied to it, whereby a charging of the cylinder is achieved. Frequently, a charge air cooler is provided downstream of the compressor in the intake system, with which the compressed charge air is cooled before entering the at least one cylinder. The radiator lowers the temperature and thus increases the density of the charge air, so that the intercooler for a better filling of the cylinder, d. H. contributes to a larger air mass. There is a compaction by cooling.

The advantage of an exhaust gas turbocharger compared to a mechanical supercharger is that there is no mechanical connection to the power transmission between the supercharger and the internal combustion engine or is required. While a mechanical supercharger obtains the energy required for its drive completely from the internal combustion engine and thus reduces the power provided and thus adversely affects the efficiency, the exhaust gas turbocharger uses the exhaust gas energy of the hot exhaust gases.

The charge is - as already mentioned - the increase in performance. The air required for the combustion process is compressed, which allows each cylinder per working cycle, a larger air mass can be supplied. As a result, the fuel mass and thus the medium pressure can be increased.

The charge is a suitable means to increase the capacity of an internal combustion engine with unchanged displacement or to reduce the displacement at the same power. In any case, the charging leads to an increase in space performance and a lower power mass. If the displacement is reduced, then the load spectrum can be shifted to higher loads, where the specific fuel consumption is lower.

Charging thus supports the constant effort in the development of internal combustion engines to minimize fuel consumption, d. H. to improve the efficiency of the internal combustion engine.

Another fundamental goal is to reduce pollutant emissions. In the solution of this task, the charging can also be effective. With targeted design of the charge namely benefits in efficiency and in the exhaust emissions can be achieved. In order to comply with future limits for pollutant emissions in addition to the charge but further internal engine measures required.

Exhaust gas recirculation, for example, reduces nitrogen oxide emissions. The recirculation rate x _{AGR is} determined to be x _AGR = m _AGR / (m _AGR + m _{fresh air} ), where m _AGR denotes the mass of recirculated exhaust gas and m _{fresh air,} the fresh air supplied.

The inventive supercharged by exhaust gas turbocharger internal combustion engine is equipped with an exhaust gas recirculation, namely with a low-pressure EGR. In contrast to a high pressure EGR, which introduces exhaust gas taken from the exhaust gas removal system upstream of the turbine into the intake system downstream of the compressor, at a low pressure EGR, exhaust gas is returned to the inlet side which has already passed through the turbine. For this purpose, the low-pressure EGR comprises a return line, which branches off downstream of the turbine from the Abgasabführsystem and opens upstream of the compressor in the intake system.

The main advantage of the low-pressure EGR compared with the high-pressure EGR is that the exhaust gas flow introduced into the turbine is not reduced by the amount of recirculated exhaust gas in the case of exhaust gas recirculation. It is always the entire exhaust gas flow to the turbine to generate a sufficiently high boost pressure available.

The exhaust gas, which is returned to the inlet side by means of low-pressure EGR and is preferably cooled, is mixed with fresh air upstream of the compressor. The mixture of fresh air and recirculated exhaust gas produced in this way forms the charge air, which is supplied to the compressor and compressed.

It is harmless that exhaust gas is passed through the compressor in the context of low-pressure EGR, since preferably exhaust gas is used, which downstream of the turbine of an exhaust aftertreatment, in particular in a particulate filter was subjected. Deposits in the compressor, which change the geometry of the compressor, in particular the flow cross-sections, and thus worsen the efficiency of the compressor, are therefore not to be feared.

However, problems may arise upstream of the compressor as the temperature of the recirculated hot exhaust gas decreases and condensate forms. There are two scenarios to distinguish.

On the one hand, condensate can form when the returned hot exhaust gas coincides with cool fresh air and is mixed. The exhaust gas cools, whereas the temperature of the fresh air is raised. The temperature of the mixture of fresh air and recirculated exhaust gas, d. H. the charge air temperature is below the exhaust gas temperature of the recirculated exhaust gas. As part of the cooling of the exhaust gas previously liquids in gaseous form in the exhaust gas or in the charge air, in particular water, condense out when the taut temperature of a component of the gaseous charge air flow is exceeded.

It comes to a condensation in the free charge air flow, often impurities in the charge air form the starting point for the formation of condensate droplets.

On the other hand, condensate can form if the recycled hot exhaust gas or the charge air strikes the inner wall of the intake system or on the inner wall of the compressor housing, since the wall temperature is usually below the taut temperature of the relevant gaseous components.

Condensate and condensate droplets are undesirable and lead to increased noise in the intake system, possibly damaging the blades of the at least one compressor impeller. The latter is associated with a reduction in the efficiency of the compressor.

The problem described above is exacerbated with increasing recirculation rate, since with the increase in the amount of recirculated exhaust gas, the proportions of the individual exhaust gas components in the charge air inevitably increase, in particular the proportion of water contained in the exhaust gas. According to the prior art, therefore, the amount of exhaust gas recirculated by means of low-pressure EGR is often limited in order to prevent or reduce the condensation out. The necessary limitation of the low-pressure EGR on the one hand and the high exhaust gas recirculation rates required for a significant reduction of the nitrogen oxide emissions on the other hand lead to different objectives in the dimensioning of the recirculated exhaust gas quantity. The legal requirements for the reduction of nitrogen oxide emissions illustrate the high relevance of this problem in practice.

The indicated conflict in an exhaust gas turbocharged supercharged and equipped with a low-pressure EGR internal combustion engine can not be resolved in the prior art, so that in addition to the low-pressure EGR additionally a high-pressure EGR must be used.

Against this background, it is an object of the present invention to provide a supercharged internal combustion engine according to the preamble of claim 1, with which the known from the prior art disadvantages can be overcome and high exhaust gas recirculation rates can be realized by means of low-pressure EGR and with the In particular, the condensation can be counteracted in the context of low-pressure EGR.

A further sub-task of the present invention is to show a method for operating such an internal combustion engine.

• – einem Ansaugsystem zum Zuführen von Ladeluft,
• – einem Abgasabführsystem zum Abführen von Abgas,
• – mindestens einem Abgasturbolader, der eine im Abgasabführsystem angeordnete Turbine und einen im Ansaugsystem angeordneten Verdichter umfasst, wobei der Verdichter mit mindestens einem in einem Verdichtergehäuse auf einer drehbaren Welle gelagerten Laufrad ausgestattet ist, und
• – einer Abgasrückführung umfassend eine Rückführleitung, die stromabwärts der Turbine des mindestens einen Abgasturboladers vom Abgasabführsystem abzweigt und stromaufwärts des mindestens einen Verdichterlaufrades unter Ausbildung eines Knotenpunktes in das Ansaugsystem mündet,

die dadurch gekennzeichnet ist, dass

• – das Ansaugsystem stromaufwärts des Verdichtergehäuses und stromabwärts des Knotenpunktes mit einer Heizeinrichtung ausgestattet ist.

The first subtask is solved by a supercharged internal combustion engine

• An intake system for supplying charge air,
• An exhaust gas removal system for removing exhaust gas,
• - At least one exhaust gas turbocharger, which comprises a turbine arranged in the Abgasabführsystem and a compressor arranged in the intake system, wherein the compressor is equipped with at least one mounted in a compressor housing on a rotatable shaft impeller, and
• An exhaust gas recirculation comprising a return line, which branches off from the exhaust gas removal system downstream of the turbine of the at least one exhaust gas turbocharger and opens into the intake system upstream of the at least one compressor impeller, forming a junction point,

which is characterized in that

• - The intake system is equipped upstream of the compressor housing and downstream of the node with a heater.

The intake system of the internal combustion engine according to the invention is equipped with a heating device with which the temperature of the inner wall of the intake system can be increased. By means of heating, the wall temperature can be raised above the dew temperature of the gaseous components of the exhaust gas or the charge air.

Condensation on the inner wall of the intake system or on the inner wall of the compressor housing can be avoided or reduced in this way.

By blocking the formation of condensate in the intake system and in the inlet region of the compressor, an increased noise emission due to condensate droplets is also eliminated. The risk of damaging the impeller vanes of the at least one compressor is eliminated. The efficiency of the compressor is increased or remains unaffected by the exhaust gas recirculation by means of low-pressure EGR.

It is not necessary to limit the amount of exhaust gas recirculated by means of low-pressure EGR, so that high recirculation rates can be realized by means of low-pressure EGR in order to significantly reduce nitrogen oxide emissions.

Thereby, the first object of the invention is achieved, namely provided a supercharged internal combustion engine, can be realized by means of low-pressure EGR high exhaust gas recirculation rates and counteracted in particular with the formation of condensate in the context of low-pressure EGR.

Further advantageous embodiments of the internal combustion engine are discussed in connection with the subclaims.

Embodiments of the internal combustion engine in which the compressor of the at least one exhaust-gas turbocharger is a radial compressor are advantageous. This embodiment allows a tight packaging of the exhaust gas turbocharger and thus the overall charge. The compressor housing can be designed as a spiral or worm housing, wherein the deflection of the charge air flow in the compressor of the exhaust gas turbocharger can be used in an advantageous manner to the compressed charge air on the shortest path from the outlet side, on which the turbine of the exhaust gas turbocharger is often arranged on the Lead inlet side.

In this context, embodiments of the internal combustion engine in which the turbine of the at least one exhaust-gas turbocharger is a radial turbine are advantageous. This embodiment also allows a tight packaging of the exhaust gas turbocharger and thus the overall charge.

Unlike the turbines, compressors are defined by their outflow. A radial compressor is thus a compressor whose outflow from the blades takes place substantially radially. In the context of the present invention, essentially radial means that the velocity component in the radial direction is greater than the axial velocity component.

Embodiments of the internal combustion engine in which the compressor of the at least one exhaust gas turbocharger is an axial compressor can also be advantageous. The outflow from the impeller blades of an axial compressor takes place substantially axially.

Embodiments of the internal combustion engine in which the compressor of the at least one exhaust-gas turbocharger has an inlet region which runs coaxially to the shaft of the compressor and is designed so that the flow of the charge air to the compressor takes place essentially axially are advantageous.

In an axial flow of the compressor often eliminates a deflection or change in direction of the charge air flow in the intake upstream of the at least one compressor impeller, whereby unnecessary pressure losses in the charge air flow due to flow deflection can be avoided and the pressure of the charge air is increased at the inlet to the compressor of the exhaust gas turbocharger. The lack of change in direction also reduces the contact of the exhaust gas or the charge air with the inner wall of the intake system or with the inner wall of the compressor housing and thus reduces the heat transfer and condensation.

Embodiments of the internal combustion engine in which downstream of the turbine of the at least one exhaust-gas turbocharger a first shut-off element is arranged in the exhaust-gas removal system are advantageous, with the return line branching off from the exhaust-gas removal system between the turbine and the shut-off element. The first shut-off element may be used to increase the exhaust pressure upstream in the exhaust system and thereby contribute to an increase in the pressure differential between the exhaust system and the intake system. This offers particular advantages at high recirculation rates, which require a larger pressure gradient.

Embodiments of the internal combustion engine in which upstream of the node a second shut-off element is arranged in the intake system are advantageous. The second shut-off element is used on the inlet side to reduce the pressure in the intake system and thus - as the first shut-off - contribute to an increase in the pressure gradient between the Abgasabführsystem and the intake system.

In this context, embodiments of the internal combustion engine in which the first and / or second shut-off element is a pivotable flap are advantageous.

Embodiments of the internal combustion engine in which the heating device is arranged at the junction are advantageous. The recirculated exhaust gas is usually significantly deflected at the junction when entering the intake system. This noticeable change in direction is inherent with a wall contact, d. H. connected to a contact on the inner wall of the intake system. In this respect, it is advantageous to heat the area in which the recirculated exhaust gas enters.

Advantageous embodiments of the internal combustion engine, in which the exhaust gas recirculation includes a shut-off, which serves to adjust the amount of recirculated exhaust gas.

Embodiments of the internal combustion engine in which the shut-off element which serves to adjust the amount of recirculated exhaust gas are arranged at the junction are advantageous.

Particularly advantageous are embodiments which are characterized in that the shut-off element is a combined valve with which both the amount of recirculated exhaust gas and the amount of fresh air can be adjusted.

Embodiments of the internal combustion engine in which the heating device is integrated in the shut-off element are advantageous.

In principle, embodiments of the internal combustion engine in which the heating device is arranged on the outside of the intake system are advantageous, so that there is no influence on the gas flow in the intake system.

In this context, embodiments of the internal combustion engine in which the heating device is integrated in a wall of the intake system are advantageous.

Embodiments of the internal combustion engine in which the heating device is an electrical heating device are advantageous. An electric heater can be used at any time in case of need and be activated independently of the operating condition of the internal combustion engine for heating the inner wall of the intake system. A supply of energy to the electric heater can be done for example by means of the on-board battery of a vehicle.

In this context, embodiments of the internal combustion engine in which the electric heating device comprises at least one heatable wire are advantageous. This wire can already be introduced during the manufacture of the intake system or of the shut-off element, for example, into the wall of the intake system or of the shut-off element. In this way, a high heat transfer from the wire in the wall is guaranteed or realized.

Embodiments of the internal combustion engine in which the heating device comprises at least one channel which can be acted upon by a fluid can also be advantageous. The internal combustion engine usually has a plurality of operating fluids that can be used or used for heat input or as a heat source, for example, the coolant of a liquid cooling or the oil from an oil circuit of the internal combustion engine.

In this connection, however, embodiments of the invention are also advantageous Internal combustion engine, in which the at least one channel with the Abgasabführsystem is at least connectable. In the present case, the hot exhaust gas is used for a heat input or as a heat source, wherein the exhaust gas can be removed from the exhaust gas removal system or the exhaust gas recirculation.

For internal combustion engines with liquid cooling, for the reasons already mentioned, embodiments are also advantageous in which the at least one channel is at least connectable to the liquid cooling.

Advantageous embodiments of the internal combustion engine, in which the node is formed and arranged in the vicinity of the at least one compressor impeller to form a distance .DELTA. A compressor-near arrangement of the node shortens the distance of the hot recirculated exhaust gas from the point of introduction into the intake system to the at least one compressor impeller so that the time in which condensate droplets can form in the free charge air flow is reduced. A formation of condensate droplets is counteracted.

In this context, embodiments of the internal combustion engine are advantageous in which for the distance Δ applies: Δ ≤ 1.5D _V , where D _V indicates the diameter of the at least one compressor impeller. According to advantageous embodiments, which applies to the distance Δ: Δ ≤ 1.0D _V, preferably 0.75D Δ ≤ _V.

Also advantageous are embodiments of the internal combustion engine in which the compressor housing is equipped with an additional heating device upstream of the at least one compressor impeller.

Embodiments of the internal combustion engine in which at least two exhaust-gas turbochargers are provided are advantageous.

Often, the design of the turbocharger turbocharger is difficult, with basically a noticeable increase in performance in all speed ranges is sought. But it is often observed a strong torque drop when falling below a certain speed.

This torque drop becomes understandable if it is taken into account that the boost pressure ratio depends on the turbine pressure ratio. If the engine speed is reduced, this leads to a smaller exhaust gas mass flow and thus to a smaller turbine pressure ratio. Consequently, the boost pressure ratio also decreases toward lower speeds. This is equivalent to a boost pressure drop or torque drop.

If a small exhaust gas turbocharger, d. H. used an exhaust gas turbocharger with a small turbine cross section, thereby the turbine pressure ratio can be increased. If the exhaust gas mass flow exceeds a critical size, part of the exhaust gas flow is conducted past the turbine by means of a bypass line as part of the so-called exhaust gas blow-off. Such a turbine is also referred to as a waste gate turbine. However, this variant has the disadvantage that the charging behavior at high speeds is insufficient and the torque drop is only shifted to low speeds. In addition, this approach, d. H. the reduction of the turbine cross-section limits, since the desired charging and performance increase should be possible without restriction and to the desired extent, even at high speeds.

The torque characteristic of a supercharged internal combustion engine may be further characterized by a plurality of turbochargers arranged in parallel, i. H. be improved by a plurality of parallel turbines of smaller turbine cross-section, with successive turbines are switched on with increasing exhaust gas.

The torque characteristic can also be advantageously influenced by means of a plurality of exhaust-gas turbochargers connected in series. By switching in series of two exhaust gas turbochargers, one of which is an exhaust gas turbocharger as a high-pressure stage and an exhaust gas turbocharger as a low-pressure stage, the engine map can be widened in an advantageous manner, both towards smaller compressor streams and towards larger compressor streams.

In particular, in the case of the exhaust gas turbocharger serving as a high-pressure stage, the pumping limit can be shifted towards smaller compressor flows, which means that high boost pressure ratios can be achieved even with small compressor flows, which significantly improves the torque characteristic in the lower rpm range. This is achieved by designing the high-pressure turbine for small exhaust gas mass flows and providing a bypass line, with which increasing exhaust gas mass flow increasingly exhaust gas is passed to the high-pressure turbine. For this purpose, the bypass line branches off the exhaust-gas removal system upstream of the high-pressure turbine and returns to the exhaust-gas removal system upstream of the low-pressure turbine. In the bypass line, a shut-off element is arranged to control the exhaust gas flow passed past the high-pressure turbine.

In order to achieve a significant reduction in nitrogen oxide emissions, high exhaust gas recirculation rates are required. Therefore, embodiments may also be advantageous in which an additional Exhaust gas recirculation is provided, which comprises a line which branches off upstream of the turbine of the at least one exhaust gas turbocharger from the Abgasabführsystem and opens downstream of the compressor of the at least one exhaust gas turbocharger back into the intake system.

In contrast to the low-pressure EGR already mentioned, exhaust gas is taken from the exhaust system at a high-pressure EGR upstream of the turbine and introduced into the intake system downstream of the compressor, i. H. Exhaust gas recirculated, which has not yet passed through the turbine. One advantage of the high-pressure EGR is that there is a sufficiently high pressure gradient for conveying the exhaust gas and the exhaust gas does not have to undergo any exhaust gas aftertreatment.

The second sub-task on which the invention is based, namely to disclose a method for operating an internal combustion engine of the type described above, is achieved by a method which is characterized in that the intake system is heated by means of heating in order to counteract the excretion of condensate, if Exhaust gas is returned via return line.

What has already been said for the internal combustion engine according to the invention also applies to the method according to the invention, which is why at this point in general reference is made to the statements made above with regard to the supercharged internal combustion engine. The various internal combustion engines sometimes require different process variants.

In the following the invention is based on an embodiment according to 1 described in more detail. Hereby shows:

1 schematically the arranged in the intake compressor of a first embodiment of the internal combustion engine together with exhaust gas recirculation, partially cut.

1 schematically shows the intake system 1 arranged compressor 3 a first embodiment of the internal combustion engine together with exhaust gas recirculation 5 , partially cut.

For supplying the charge air to the cylinders, the internal combustion engine has an intake system 1 and for the purpose of charging the cylinders, there is provided an exhaust gas turbocharger having a turbine (not shown) disposed in the exhaust gas discharge system and one in the intake system 1 arranged compressor 2 includes. The compressor 2 is a centrifugal compressor 2 B in its case 2c at least one impeller is mounted on a rotatable shaft.

The compressor 2 the exhaust gas turbocharger has an inlet area 2a on, coaxial with the shaft of the compressor 2 runs and is formed so that the flow of charge air to the compressor 2 the exhaust gas turbocharger takes place substantially axially and the section of the intake system 1 upstream of the compressor 2 has no direction changes.

The internal combustion engine is further equipped with exhaust gas recirculation 5 equipped, which is a return line 5a which branches off the exhaust gas removal system downstream of the turbine and upstream of the compressor 2 or compressor impeller forming a node 5c into the intake system 1 empties. To set the amount of recirculated exhaust gas is a shut-off 5b which is present at the junction 5c is arranged. Upstream of the junction 5c is in the intake system 1 a second shut-off element 4 in the form of a throttle 4 arranged. This throttle 4 Used to adjust the amount of fresh air and to reduce the pressure in the intake system 1 downstream of the flap 4 , The flap 4 can thus increase the pressure gradient between the exhaust system and the intake system 1 be used.

The intake system 1 upstream of the compressor housing 2c and downstream of the node 5c is with a heater 3 fitted. Present is the heater 3 an electric heater 3a which includes a heated wire and outside of the intake system 1 is arranged, so that an influence on the gas flow in the intake system 1 omitted. Here is the heater 3 on the one hand in the shut-off 5b and on the other hand into a wall of the intake system 1 integrated.

The compressor housing 2c is upstream of the at least one compressor impeller with an additional heater 6 fitted. In the present case is also this heater 6 an electric heater 3a , one in the compressor housing 2c includes integrated heatable wire.

LIST OF REFERENCE NUMBERS

1

 intake system

2

 Compressor of the exhaust gas turbocharger

2a

 Entry area of the compressor of the exhaust gas turbocharger

2 B

 centrifugal compressors

2c

 Compressor housing of the exhaust gas turbocharger

3

 heater

3a

 electric heating device

4

 Throttle valve, second shut-off element

5

 Exhaust gas recirculation

5a

 Return line

5b

 Shut-off element of the exhaust gas recirculation

5c

 junction

6

 additional heating device

Δ

 Distance of the node to the compressor wheel

AGR

 Exhaust gas recirculation

D _V

 Diameter of the at least one compressor impeller

m _AGR

 Mass of recirculated exhaust gas

_{Fresh air}

 Mass of supplied fresh air or charge air

x _AGR

 Exhaust gas recirculation rate

Claims (20)

Charged internal combustion engine with - an intake system ( 1 ) for supplying charge air, - an exhaust gas removal system for discharging exhaust gas, - at least one exhaust gas turbocharger having a turbine arranged in the exhaust gas removal system and one in the intake system ( 1 ) arranged compressors ( 2 ), wherein the compressor ( 2 ) with at least one in a compressor housing ( 2c ) is mounted on a rotatable shaft mounted impeller, and - an exhaust gas recirculation ( 5 ) comprising a return line ( 5a ), which branches off from the exhaust gas removal system downstream of the turbine of the at least one exhaust-gas turbocharger and upstream of the at least one compressor impeller, to form a junction (FIG. 5c ) into the intake system ( 1 ), characterized in that - the intake system ( 1 ) upstream of the compressor housing ( 2c ) and downstream of the node ( 5c ) with a heating device ( 3 ) Is provided. Supercharged internal combustion engine according to claim 1, characterized in that the compressor ( 2 ) of the at least one exhaust gas turbocharger a radial compressor ( 2 B ). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the compressor ( 2 ) of the at least one exhaust gas turbocharger an inlet region ( 2a ) coaxial with the shaft of the compressor ( 2 ) and is formed so that the flow of charge air to the compressor ( 2 ) is effected substantially axially. Supercharged internal combustion engine according to one of the preceding claims, characterized in that downstream of the turbine of the at least one exhaust gas turbocharger, a first shut-off element is arranged in the Abgasabführsystem, wherein the return line ( 5a ) branches off from the Abgasabführsystem between the turbine and the shut-off. Supercharged internal combustion engine according to one of the preceding claims, characterized in that upstream of the node ( 5c ) a second shut-off element ( 4 ) in the intake system ( 1 ) is arranged. Supercharged internal combustion engine according to claim 4 or 5, characterized in that the first and / or second shut-off element ( 4 ) a pivotable flap ( 4 ). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the heating device ( 3 ) at the junction ( 5c ) is arranged. Supercharged internal combustion engine according to one of the preceding claims, characterized in that a shut-off element ( 5b ) at the junction ( 5c ) is arranged, which serves to adjust the amount of recirculated exhaust gas. Supercharged internal combustion engine according to claim 8, characterized in that the heating device ( 3 ) in the shut-off element ( 5b ) is integrated. Supercharged internal combustion engine according to one of claims 1 to 8, characterized in that the heating device ( 3 ) on the outside of the intake system ( 1 ), so that an influence on the gas flow in the intake system ( 1 ) is omitted. Supercharged internal combustion engine according to claim 10, characterized in that the heating device ( 3 ) in a wall of the intake system ( 1 ) is integrated. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the heating device ( 3 ) an electric heater ( 3a ). Supercharged internal combustion engine according to claim 12, characterized in that the electric heating device ( 3a ) comprises at least one heatable wire. Supercharged internal combustion engine according to one of claims 1 to 11, characterized in that the heating device ( 3 ) comprises at least one duct acted upon by a fluid. Supercharged internal combustion engine according to claim 14, characterized in that the at least one channel with the Abgasabführsystem is at least connectable. Supercharged internal combustion engine according to claim 14, wherein a liquid cooling is provided, characterized in that the at least one channel with the liquid cooling is at least connectable. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the node ( 5c ) is formed and arranged in the vicinity of the at least one compressor impeller while forming a distance Δ. Supercharged internal combustion engine according to claim 17, characterized in that for the distance Δ applies: Δ ≤ 1.5D _V , wherein D _V indicates the diameter of the at least one compressor impeller. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the compressor housing ( 2c ) upstream of the at least one compressor impeller with an additional heating device ( 6 ) Is provided. Method for operating a supercharged internal combustion engine according to one of the preceding claims, characterized in that the intake system ( 1 ) by means of heating device ( 3 ) is heated to counteract a discharge of condensate, if exhaust gas via return line ( 5a ) is returned.

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