DE102018209238A1 - Exhaust-engine-loaded 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 with 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 exhaust gas removal system and a compressor (2) arranged in the intake system (1) wherein the compressor (2) is equipped with at least one impeller mounted on a rotatable shaft in a compressor housing, and an exhaust gas recirculation comprising a return line upstream of the at least one compressor impeller forming a first junction (5c) in the intake system (1) It is intended to provide an internal combustion engine of the type mentioned, with which large amounts of exhaust gas upstream of the compressor can be introduced into the intake system and with which, in particular, the formation of condensate in the context of exhaust gas recirculation can be counteracted. This is achieved with an internal combustion engine which is d It is characterized in that the intake system (1) is equipped upstream of the at least one compressor wheel with a phase change material (4) which is in the form of a liquid phase or a solid phase, the phase change material (4) either absorbing heat or giving off heat in a phase transition ,

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 stromaufwärts des mindestens einen Verdichterlaufrades unter Ausbildung eines ersten 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 comprising a return line, which opens upstream of the at least one compressor impeller to form a first node in the intake system.

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 relates to diesel engines and gasoline engines, but also to hybrid internal combustion engines, i. Internal combustion engines, which are operated with a hybrid combustion method, and hybrid drives, which comprise at least one further torque source for driving a motor vehicle in addition to the internal combustion engine, for example a drive-connected to the engine or drive connected electric machine, which instead of the internal combustion engine or in addition to Internal combustion engine gives off power.

In the development of internal combustion engines, efforts are constantly being made to minimize fuel consumption. Internal combustion engines are therefore increasingly equipped with a charge, the charge is primarily a method of increasing performance, in which the charge air required for the engine combustion process is compressed, whereby each cylinder per cycle a larger charge 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. By charging in combination with a suitable transmission design and a so-called downspeeding can be realized, in which also a lower specific fuel consumption can be achieved.

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

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, i. 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.

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 designates} the mass of recirculated exhaust gas and m _{fresh air} the fresh air supplied. The oxygen provided via exhaust gas recirculation may need to be considered.

The inventive supercharged by exhaust gas turbocharger internal combustion engine is equipped with an exhaust gas recirculation, the return line opens upstream of the at least one compressor impeller to form a first node in the intake system.

The exhaust gas recirculation may in the present case be a high-pressure EGR, which removes exhaust gas from the exhaust gas removal system upstream of the turbine of the exhaust gas turbocharger and introduces it into the intake system, or a low-pressure EGR which has recirculated exhaust gas to the inlet side, which has already passed through the turbine. A low pressure EGR includes a return line that branches off the exhaust removal system downstream of the turbine and discharges into the intake system upstream of the compressor.

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 recirculated to the inlet side and preferably cooled exhaust gas is mixed upstream of the compressor with fresh air. 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 as part of the exhaust gas recirculation, 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, i. 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. In the prior art, therefore, the amount of recirculated exhaust gas is often limited in order to prevent or reduce the condensation. The necessary limitation on the one hand and the high exhaust gas recirculation rates required for a significant reduction in 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.

According to the prior art, the intake system is therefore also provided in a particular case with a heater with which the temperature of the inner wall of the intake system can be increased. Condensation on the inner wall of the intake system can be avoided in this way or diminished. It is a complex and costly concept.

In this respect, the indicated conflict according to the prior art can not be resolved cost-effectively, so that in addition often a high-pressure EGR must be used, the exhaust gas taken from the Abgasabführsystem upstream of the turbine of the exhaust gas turbocharger downstream of the compressor in the intake system and located in the intake system Introduced compressed and heated charge air.

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 disadvantages known from the prior art are overcome, large amounts of exhaust gas upstream of the compressor can be introduced into the intake system and with the particular the condensation can be counteracted in the context of exhaust gas recirculation.

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 stromaufwärts des mindestens einen Verdichterlaufrades unter Ausbildung eines ersten Knotenpunktes in das Ansaugsystem mündet,

die dadurch gekennzeichnet ist, dass

• - das Ansaugsystem stromaufwärts des mindestens einen Verdichterlaufrades mit einem Phasenwechselmaterial ausgestattet ist, welches als flüssige Phase oder als feste Phase vorliegt, wobei das Phasenwechselmaterial bei einem Phasenübergang entweder Wärme aufnimmt oder Wärme abgibt.

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 opens into the intake system upstream of the at least one compressor impeller, forming a first junction,

which is characterized in that

• - The intake system is equipped upstream of the at least one compressor impeller with a phase change material, which is present as a liquid phase or as a solid phase, wherein the phase change material in a phase transition either absorbs heat or releases heat.

The intake system of the internal combustion engine according to the invention is equipped with a phase change material with which the temperature of the inner wall of the intake system in case of need, for example, before or during a cold start of the internal combustion engine can be increased. By means of heating, the wall temperature can be raised above the dew temperature of the gaseous components of the charge air or of the recirculated exhaust gas.

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.

Limiting the amount of recirculated exhaust gas introduced into the intake system upstream of the compressor is not required, so that high recirculation rates can be realized in order to significantly reduce nitrogen oxide emissions.

If necessary, the phase change material is activated, for example mechanically or electrically stimulated, in such a way that heat is released and introduced into the intake system. In this case, the phase change material undergoes a phase transition from the liquid phase to the solid phase or vice versa; depending on the material used.

In order to prepare the phase change material again for the next use or the next use, heat must be supplied, wherein the phase change material again performs a phase transition in the context of this regeneration in the reverse direction, i. back from the solid phase to the liquid phase or vice versa.

The phase change material either releases heat or absorbs heat during a phase transition. That the material acts either as a thermal sink, i. as a heat-absorbing energy storage, or as a heat-emitting heater.

Thus, the first object of the invention is achieved, namely provided a supercharged internal combustion engine, with which the known from the prior art disadvantages are overcome, large amounts of exhaust gas upstream of the compressor can be introduced into the intake and with the particular condensation in the context of exhaust gas recirculation can be counteracted.

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

Advantageous embodiments of the supercharged internal combustion engine, in which the intake system upstream of the compressor housing is equipped with a phase change material, which is present as a liquid phase or as a solid phase, wherein the phase change material in a phase transition either absorbs heat or gives off heat.

As such, the compressor housing forms the intake system so that it can be considered part of the intake system. According to the above embodiment, however, the compressor housing is excluded. The phase change material is expressly not placed or provided in the compressor housing, but in the intake system upstream of the compressor housing.

Also advantageous are embodiments of the supercharged internal combustion engine in which the intake system is equipped at the first node with a phase change material which is present as a liquid phase or as a solid phase, wherein the phase change material either absorbs heat or gives off heat during a phase transition.

At the point of the intake system at which the recirculated exhaust gas is introduced, namely at the first node, the exhaust gas is mixed with the fresh air and regularly deflected stronger, so that the risk of condensation on the first node is particularly large. Therefore, it is particularly useful to equip the intake system at the first node with a phase change material.

Embodiments of the supercharged internal combustion engine in which the phase change material ( 4 ) gives off heat in a phase transition from the liquid phase to the solid phase.

In this context, embodiments of the supercharged internal combustion engine in which the phase change material absorbs heat in a phase transition from the solid phase into the liquid phase are advantageous.

But can also be advantageous embodiments of the supercharged internal combustion engine, in which the phase change material emits heat at a phase transition from the solid phase into the liquid phase.

Embodiments of the supercharged 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 route 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 supercharged 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 supercharged 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 supercharged 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 inflow 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 supercharged internal combustion engine in which the Return line downstream of the turbine of the at least one exhaust gas turbocharger branches off to form a second node from the Abgasabführsystem. Then, the exhaust gas recirculation is a low-pressure EGR whose return line branches off from the exhaust gas removal system downstream of the turbine and opens into the intake system upstream of the compressor.

When connected exhaust gas recirculation of the exhaust gas flow introduced into the turbine is not reduced by the recirculated exhaust gas amount, so that always the entire exhaust gas flow is provided to the turbine to generate a sufficiently high boost pressure.

In this context, embodiments of the supercharged internal combustion engine in which downstream of the second node a first shut-off element in the exhaust-gas removal system is arranged are advantageous. 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 supercharged internal combustion engine in which a second shut-off element is arranged in the intake system upstream of the first node 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 supercharged internal combustion engine in which the first and / or second shut-off element is a pivotable flap are advantageous.

Embodiments of the supercharged internal combustion engine in which the intake system for receiving the phase change material has at least one cavity are advantageous.

The intake system according to the invention must have at least one cavity or at least one container for receiving the phase change material. A cavity or container for receiving the phase change material could be formed as part of a manufacturing process as an integral part of the intake system. The intake system could be modular in construction, wherein a cavity is formed during assembly, which receives the phase change material.

A cavity could be formed by providing the actual intake system with a casing, so that a cavity is formed between the intake system and the at least one spaced-apart formwork element, in which phase change material is received. The suction system extended by the casing then comprises the cavity or the container for receiving the phase change material.

Also advantageous for the reasons mentioned above, embodiments of the supercharged internal combustion engine, in which the intake system for receiving the phase change material is at least partially formed double-walled.

The intake system need not be a monolithic component, in which the at least one cavity is incorporated as part of the manufacturing process as an integral part. Rather, the intake system is preferably a system constructed of sheets, for example, in which the at least one cavity is formed during assembly by using spaced apart components or formwork elements. This also gives the possibility to retrofit already existing or already designed intake systems.

Advantageous embodiments of the supercharged 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 supercharged internal combustion engine in which the shut-off element which serves to adjust the recirculated exhaust gas quantity are arranged at the first node point are advantageous.

Particularly advantageous in this context 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. Such a combined valve may comprise a pivotable flap and further valve components in addition to the valve housing.

In this context, embodiments of the supercharged internal combustion engine in which the shut-off element is equipped with the phase change material as part of the intake system are advantageous.

If a combined valve is used as the shut-off element, preferably the Valve housing and / or the pivotable flap equipped with the phase change material.

The shut-off element as such or the valve housing forms the intake system with, so that it can be regarded as part of the intake system. According to the above embodiment, the phase change material is placed in the shut-off element or in the valve housing.

Embodiments of the supercharged internal combustion engine in which the intake system is equipped with a heating device upstream of the at least one compressor impeller are advantageous.

A heating device can be activated and used at any time to regenerate the phase change material by supplying heat, and if necessary in place of the phase change material or in addition to the heating of the inner wall of the intake system.

In this context, embodiments of the supercharged internal combustion engine in which the heating device comprises at least one electrically heatable wire integrated in the intake system are advantageous.

A supply of this electric heater with energy can be done independently of the operating state of the internal combustion engine, for example by means of the on-board battery of a vehicle. The wire can already be introduced during the manufacture of the intake system, for example, be implemented in the intake system. In this way, a high heat transfer from the wire into the walls of the intake system is ensured or realized.

Embodiments of the supercharged internal combustion engine may also be advantageous in the present context, in which the heating device comprises at least one channel which is arranged in the intake system and can be acted upon by a fluid. The internal combustion engine usually has a plurality of operating fluids that can be used or used for heat input into the intake system, for example, the coolant of a liquid cooling or the oil from an oil circuit of the internal combustion engine.

In this context, embodiments of the supercharged internal combustion engine in which the at least one channel is at least connectable to the exhaust gas removal system are advantageous. In the present case, the hot exhaust gas is used for a heat input into the housing, wherein the exhaust gas can be taken from the exhaust gas removal system or the exhaust gas recirculation.

In supercharged internal combustion engines with liquid cooling, embodiments are also advantageous in this context, which are characterized in that the at least one channel is at least connectable to the liquid cooling.

Advantageous embodiments of the supercharged internal combustion engine, in which the first node in the vicinity of the at least one compressor impeller is formed and arranged to form a distance .DELTA. A compressor near arrangement of the first 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 are advantageous in which for the distance Δ applies: Δ ≦ 1.5Dv, wherein 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.

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.

The torque characteristic of a supercharged internal combustion engine may also be represented by a plurality of turbochargers arranged in parallel, i. be improved by a plurality of parallel turbines of smaller turbine cross-section, with successive turbines are switched on with increasing exhaust gas; similar to a register charge.

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 compressor map can be widened in an advantageous manner, both towards smaller compressor streams as well as towards larger compressor streams.

In addition to an exhaust gas turbocharger, in principle a mechanical or electrical supercharger can also be provided.

The second sub-task underlying the invention, namely to show a method for operating a supercharged internal combustion engine of a type described above, is achieved by a method which is characterized in that the phase change material is activated to release heat in the context of a phase transition for heating the intake system and to counteract a precipitation of condensate; preferably if exhaust gas is returned via the 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.

Advantageous process variants may be in which the phase change material is activated before or during a cold start, for example by means of ignition key.

Advantageous are process variants in which the phase change material is indirectly heated and regenerated by means of compressed charge air.

Advantageous are process variants in which the phase change material is heated and regenerated by means of hot exhaust gas.

Advantageous are process variants in which the phase change material is heated and regenerated by means of heated cooling liquid or hot oil.

• 1a schematisch ein Fragment des Ansaugsystems einer ersten Ausführungsform der Brennkraftmaschine mitsamt Abgasrückführleitung, teilweise geschnitten, und
• 1b schematisch das in der 1a dargestellte Ansaugsystem im Querschnitt entlang des in 1a gekennzeichneten Schnittes A-A.

In the following, the invention will be described with reference to an embodiment and according to the 1a and 1b described in more detail. Hereby shows:

• 1a schematically a fragment of the intake system of a first embodiment of the internal combustion engine together with exhaust gas recirculation line, partially cut, and
• 1b schematically in the 1a illustrated intake system in cross section along the in 1a marked section AA ,

1a schematically shows a fragment of the intake system 1 A first embodiment of the internal combustion engine together with exhaust gas recirculation line 5a , 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 disposed in the exhaust gas discharge system and one in the intake system 1 arranged compressor 2 includes (not shown). The entrance area 2a of the compressor 2 is indicated.

The entrance area 2a is coaxial with the shaft of the compressor 2 designed 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 first 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 arranged and as a combined valve 5b is formed, with which not only the amount of recirculated exhaust gas, but also the amount of fresh air can be adjusted. Such a combined valve 5b includes in addition to the valve housing a pivotable flap.

The intake system 1 at the first node 5c , which at the same time the valve housing of the shut-off 5b is is with a phase change material 4 equipped, which is present as a liquid phase or as a solid phase and in the context of a phase transition either absorbs heat or gives off heat. The present is the phase change material 4 in a cavity 3 the double-walled intake system 1 placed.

1b schematically shows the in the 1a illustrated intake system 1 in cross section along the in 1a marked section AA ,

LIST OF REFERENCE NUMBERS

1

intake system

2

Compressor of the exhaust gas turbocharger

2a

Entry area of the compressor

3

cavity

4

Phase change material

5

Exhaust gas recirculation

5a

Return line

5b

Exhaust gas recirculation shut-off element, EGR valve, combined valve

5c

first node

AGR

Exhaust gas recirculation

m _AGR

Mass of recirculated exhaust gas

_{Fresh air}

Mass of supplied fresh air or charge air

x _AGR

Exhaust gas recirculation rate

Claims (22)

A supercharged internal combustion engine comprising - 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 exhaust gas removal system and a compressor (2) arranged in the intake system (1), wherein the compressor (2) is equipped with at least one impeller mounted on a rotatable shaft in a compressor housing, and - an exhaust gas recirculation (5) comprising a return line (5a) upstream of the at least one compressor impeller forming a first junction (5c) into the intake system (5) 1), characterized in that - the intake system (1) upstream of the at least one compressor impeller is provided with a phase change material (4) which is in the liquid phase or in the solid phase, the phase change material (4) either absorbing heat in a phase transition or gives off heat. Charged internal combustion engine after Claim 1 , characterized in that the intake system (1) upstream of the compressor housing is provided with a phase change material (4) which is in the form of a liquid phase or a solid phase, the phase change material (4) either absorbing heat or giving off heat during a phase transition. Charged internal combustion engine after Claim 1 or 2 , characterized in that the intake system (1) at the first node (5c) is provided with a phase change material (4), which is present as a liquid phase or as a solid phase, wherein the phase change material (4) in a phase transition either absorbs heat or gives off heat , Supercharged internal combustion engine according to one of the preceding claims, characterized in that the phase change material (4) emits heat in a phase transition from the liquid phase into the solid phase. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the phase change material (4) absorbs heat in a phase transition from the solid phase into the liquid phase. Supercharged internal combustion engine according to one of claims 1 to 3, characterized in that the phase change material (4) emits heat in a phase transition from the solid phase into the liquid phase. 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 is a radial compressor. 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 has an inlet region (2a) which is coaxial with the shaft of the compressor (2) and is formed, so that the flow of the charge air to the Compressor (2) takes place substantially axially. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the return line (5a) branches off downstream of the turbine of the at least one exhaust gas turbocharger to form a second node from the Abgasabführsystem. Charged internal combustion engine after Claim 9 , characterized in that downstream of the second node, a first shut-off element is arranged in the Abgasabführsystem. Supercharged internal combustion engine according to one of the preceding claims, characterized in that upstream of the first node a second shut-off element in the intake system (1) is arranged. Charged internal combustion engine after Claim 10 or 11 , characterized in that the first and / or second shut-off element is a pivotable flap. Supercharged internal combustion engine according to one of the preceding claims, characterized in that the intake system (1) for receiving the phase change material (4) has at least one cavity (3). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the intake system (1) for receiving the phase change material (4) is at least partially double-walled. Supercharged internal combustion engine according to one of the preceding claims, characterized in that a shut-off element (5b) at the node (5c) is arranged, which serves to adjust the amount of recirculated exhaust gas. Charged internal combustion engine after Claim 15 , characterized in that the shut-off element (5b) is equipped as part of the intake system (1) with the phase change material (4). Supercharged internal combustion engine according to one of the preceding claims, characterized in that the intake system (1) upstream of the at least one compressor impeller is equipped with a heating device. Charged internal combustion engine after Claim 17 , characterized in that the heating device comprises at least one in the intake system (1) integrated electrically heatable wire. Charged internal combustion engine after Claim 17 , characterized in that the heating device comprises at least one in the intake system (1) arranged and acted upon by a fluid channel. Charged internal combustion engine after Claim 19 , characterized in that the at least one channel with the Abgasabführsystem is at least connectable. Charged internal combustion engine after Claim 19 in which a liquid cooling is provided, characterized in that the at least one channel with the liquid cooling is at least connectable. Method for operating a supercharged internal combustion engine according to one of the preceding claims, characterized in that the phase change material (4) is activated in order to release heat in the context of a phase transition for heating the intake system (1) and counteract a discharge of condensate, if exhaust via Return line (5a) is returned.

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