DE102015104179B4 - Devices for recirculating exhaust gas from an internal combustion engine in a motor vehicle - Google Patents

Abstract

Device (40a, 40b, 40c, 40d, 40e, 40f) for recirculating exhaust gas from an internal combustion engine (3) in a motor vehicle, having - an exhaust gas heat exchanger (11) which is connected to a first housing element (20) with an inlet (21 ) and an outlet (22) for the exhaust gas as well as at least one inlet (25) and at least one outlet (26) for a coolant, and- a compressor (12) which has a second housing element (30) with an inlet ( 31) and an outlet (32) for the exhaust gas, wherein the first housing element (20) of the exhaust gas heat exchanger (11) and the second housing element (30) of the compressor (12) form a housing (41) to form a coherent, are designed to be connected to a compact component, so that the exhaust gas heat exchanger (11) and the compressor (12) are arranged within the housing (41), characterized in that the housing (41) has cooling ducts which are fluidically supplied with a volume de s exhaust gas heat exchanger (11) are connected and extend to cool the compressor (12) in the housing element (30) of the compressor (12).

Description

The invention relates to devices for recirculating exhaust gas from an internal combustion engine in a motor vehicle. The devices are each designed with an exhaust gas heat exchanger and a compressor, the exhaust gas heat exchanger having a first housing element and the compressor having a second housing element.

Exhaust gas recirculation systems in motor vehicles are known from the prior art. With these systems, the nitrogen oxides in the exhaust gases, in particular in the exhaust gases of diesel-powered motor vehicles, are reduced and the consumption of petrol-powered motor vehicles is reduced. In the generic systems of exhaust gas recirculation, cooled or uncooled exhaust gas is mixed with the fresh air drawn in to the combustion engine in order to meet the legal guidelines of exhaust gas/emission regulations with regard to nitrogen oxides, but also the emission of hydrocarbons, particles or carbon dioxide. Exhaust gas is taken from the engine-external exhaust line and mixed with fresh air for renewed combustion.

During combustion at high temperatures, environmentally harmful nitrogen oxides are formed in the internal combustion engine of motor vehicles, especially when lean mixtures are used, ie in the partial load range. In order to reduce the emission of nitrogen oxides, it is necessary to lower the high temperature peaks and reduce the excess air during combustion. Due to the lower oxygen concentration of the fuel-air mixture, the speed of the combustion process and thus the maximum combustion temperatures are reduced.

Both effects are achieved by mixing a partial mass flow of the exhaust gas with the flow of fresh air drawn in by the combustion engine. In diesel-powered motor vehicles, an exhaust gas recirculation system not only reduces the oxygen content and temperature peaks during combustion but also reduces noise emissions. In the case of petrol-powered motor vehicles with an exhaust gas recirculation system, the throttling losses are also reduced.

However, mixing the recirculated exhaust gas flow with high temperatures reduces the cooling effect and thus also the efficiency of the internal combustion engine. In order to counteract these reductions, the exhaust gas is cooled in a heat exchanger, the so-called exhaust gas heat exchanger or exhaust gas recirculation cooler, before it is added. In motor vehicles powered by petrol, the additional cooling of the exhaust gas causes an increase in the compression ratio of the air supplied to the internal combustion engine.

Increasingly stricter legislation with regard to emission standards and fuel consumption requirements for motor vehicles mean that there is an increased need for cooling, while the space required for the components in the motor vehicle is becoming smaller and smaller.

Exhaust gas recirculation systems with various types of exhaust gas heat exchangers are known from the prior art. The exhaust gas to be cooled and a coolant, preferably the cooling liquid of the cooling circuit of the internal combustion engine, and thus two media, flow through the conventional exhaust gas heat exchanger. The exhaust gas is conducted through the exhaust gas heat exchanger in pipes or channels of various shapes. The coolant flows around the tubes or channels on the outside, so that the mass flow of the coolant flows in an intermediate space formed by a housing and the tubes or channels. The housing encloses the tubes or ducts and the intermediate space. Depending on the number of reversals in the flow direction of the exhaust gas flow and the associated shape of the tubes or channels, a distinction is made between exhaust gas heat exchangers with an I flow, a U flow, or an S flow.

The components conducting the exhaust gas are preferably made of stainless steel in order to achieve high temperature and corrosion resistance. Depending on the design of the exhaust gas heat exchanger, stainless steel, aluminum or plastic is used for the housing, which is in contact with the coolant and the environment.

Exhaust gas recirculation systems known from the prior art have, in addition to the exhaust gas heat exchanger, in particular a valve and a bypass with a bypass valve for recirculating uncooled exhaust gas. The bypass is opened at special operating points of the combustion engine, for example during a cold start, in order to prevent the formation of condensate in the exhaust gas heat exchanger.

In order to conduct exhaust gas from the exhaust side to the intake side of the internal combustion engine, a required pressure drop from the exhaust side to the intake side is required. In certain arrangements for extracting a portion of the exhaust gas or for feeding the exhaust gas into the fresh air on the intake side or in certain operating modes of the internal combustion engine, the pressure drop is not over sufficient to transfer the mass flow of the exhaust gas, which applies in particular to the design of the exhaust gas recirculation system at low pressure. The exhaust gas recirculation at low pressure is designed on the exhaust side after and on the suction side in front of a turbocharger. When the pressure drop is low, reliable dosing of the exhaust gas for mixing with the fresh air is also difficult to ensure. In order to ensure the pressure drop between the exhaust side and the intake side of the internal combustion engine and to promote a certain mass flow of the exhaust gas, additional compressors are used to compress the mass flow of the exhaust gas.

In the DE 10 2008 018 583 A1 discloses an exhaust gas recirculation system for an internal combustion engine with an exhaust gas recirculation valve arranged in an exhaust gas recirculation line, a first exhaust gas cooler arranged in the exhaust gas recirculation line, and a turbo cooling unit, which is arranged downstream of the first exhaust gas cooler in the exhaust gas recirculation line in the flow direction of the exhaust gas. The turbo cooling unit, which can be bypassed via a bypass duct, has a compressor, a second exhaust gas cooler and a turbine mechanically coupled to the compressor. The compressor is driven by the power delivered by the turbine.

From the US 2010/0293943 A1 discloses a power plant with an internal combustion engine, in particular a diesel engine, exhaust gas heat exchangers and a compressor driven by an exhaust gas turbine for providing the charge air. The exhaust gas turbine and the compressor are mechanically directly coupled.

Also in the DE 10 2005 032 666 A1 describes a compressor heat exchanger module with a housing in which a compressor and an air cooler are arranged. The module has a bypass associated with the air cooler and the compressor with a cooler bypass valve to bypass the air cooler.

In the WO 2010/072 227 A1 discloses an exhaust gas recirculation system for an internal combustion engine with an exhaust gas turbocharger. The system has an exhaust gas recirculation line, which is connected on the one hand to an exhaust line of the internal combustion engine for removing exhaust gas and on the other hand to a fresh air supply of the internal combustion engine. The exhaust gas recirculation line is routed via an exhaust gas compressor for increasing the pressure of the recirculated exhaust gas.

Likewise goes from the U.S. 2010/0 043 761 A1 discloses an exhaust gas recirculation system having an exhaust line with a cooler disposed between an inlet line and an outlet line. The system has a pump for pumping the exhaust gas to be recirculated. In addition, a bypass line leading from the inlet line to the outlet line past the cooler is provided, so that uncooled exhaust gas can be supplied to the internal combustion engine during the cold start phase.

As is known, electrically driven compressors, in particular radial compressors, are also used to provide the pressure drop between the exhaust gas side and the intake side of the internal combustion engine and to convey the specific mass flow of the exhaust gas. The electrically driven centrifugal compressor has a compressor wheel which is connected to an electric motor via a shaft or a gear and which is surrounded by a compressor housing specially designed to conduct the flow. Due to the special geometry, the compressor housing is preferably manufactured as a cast part made of steel or aluminum.

In exhaust gas recirculation systems known from the prior art with an exhaust gas heat exchanger and a compressor, the two components are usually designed independently and separately from one another. The separate training results in an increased number of components, an increased space requirement, a high weight and increased manufacturing costs and assembly costs. In addition, possible positive thermodynamic and procedural interactions between the exhaust gas heat exchanger and the compressor are not used.

The object of the invention is to provide a device for recirculating exhaust gas from an internal combustion engine, with which the mass flow of exhaust gas is to be cooled and/or compressed before it is returned to the fresh air sucked in by the internal combustion engine. The device should have a simple construction with a minimum number of components with a minimum space requirement and a low weight. In addition, the costs for production, maintenance and assembly should be minimal.

The object is solved by the objects with the features of the independent patent claims. Further developments are specified in the dependent patent claims.

The object is achieved by devices according to the invention for recirculating exhaust gas from an internal combustion engine in a motor vehicle, each with an exhaust gas heat exchanger and a compressor. The exhaust gas heat exchanger has a first housing element, which has an inlet and an outlet for the exhaust gas and at least one inlet and at least one outlet for having a coolant formed. The compressor has a second housing element which is formed with an inlet and an outlet for the exhaust gas.

The first housing element of the exhaust gas heat exchanger and the second housing element of the compressor are each designed as a common housing connected to form a coherent, compact component. The exhaust gas heat exchanger and the compressor are arranged within the common housing.

The first housing element of the exhaust gas heat exchanger and the second housing element of the compressor form a coherent unit, so that the device for cooling and compressing the exhaust gas is arranged within a single component. The exhaust gas heat exchanger and the compressor are integrated in one housing.

According to the design, the housing of a first device according to the invention for recirculating exhaust gas from an internal combustion engine in a motor vehicle has cooling channels which are fluidically connected to a volume of the exhaust gas heat exchanger which is acted upon by coolant. The cooling channels extend into the housing element of the compressor for cooling the compressor.

The exhaust gas heat exchanger of a second device according to the invention for recirculating exhaust gas from an internal combustion engine in a motor vehicle is designed with multiple flows. The compressor is arranged between two flows of the exhaust gas heat exchanger in the flow direction of the exhaust gas.

According to a first alternative embodiment of the invention, the housing of the device with the first housing element and the second housing element is designed as a one-piece component made of one material, in particular aluminum. The advantageous use of aluminum as a material also makes it possible to produce the housing using the casting process, with complex constructions, in particular of the housing element of the compressor, being integrated.

With the one-piece design of the housing, additional connection points, such as seams or sealing elements that have to be reworked, are avoided.

According to a second alternative embodiment of the invention, the first housing element and the second housing element of the housing of the device are connected to one another in a materially, form-fitting or non-positive manner. The two housing elements, which are separate from one another prior to assembly, are preferably soldered or welded, for example using a laser process, or screwed, crimped or clipped. The first housing element and/or the second housing element can each be designed in one piece or in multiple pieces, that is to say in each case from at least two parts. The individual parts of the housing elements are connected to form a housing when the device is assembled.

The first housing element and the second housing element can have different properties and each can also be formed as sheet metal or as cast components, with steel or plastic being used as materials, for example, in addition to aluminum.

The housing elements can advantageously be assembled as an entire device with heat exchanger and compressor in a soldering process, for example from a multi-part first housing element made of sheet metal and a one-piece cast second housing element made of steel.

According to a development of the first device according to the invention, the compressor is arranged in the direction of flow of the exhaust gas after the exhaust gas heat exchanger or, in the case of a multi-flow design of the exhaust gas heat exchanger, between two flows of the exhaust gas heat exchanger.

The exhaust gas heat exchanger is preferably designed as a single-flow, double-flow or multiple-flow flow, with each flow representing a partial region of the exhaust-gas heat exchanger as a flow path. The exhaust gas flows through the flow paths of different flows one after the other, i.e. in series. The directions of flow of the exhaust gas in successive flows are advantageously reversed.

According to a preferred embodiment of the invention, channels for conducting the exhaust gas are formed in the area of the exhaust gas heat exchanger. The channels extend from the inlet of the exhaust gas heat exchanger to the inlet of the compressor. The exhaust gas exiting the ducts of the exhaust gas heat exchanger is collected in the area of the compressor inlet and fed directly into the compressor. The exhaust gas consequently flows between the housing elements of the exhaust gas heat exchanger and the compressor, advantageously without additional built-in components, such as intermediate elements, and without additional flow paths with possible changes in direction or changes in cross section.

The exhaust gas heat exchanger advantageously has tubes that form the channels, with the Exhaust gas flows on the inside and the coolant flows on the outside of the tubes.

According to an alternative embodiment, the channels are formed in two parts from a first component and a second component. Elements for increasing the surface area, such as wavy ribs or ribs with similar geometries, are advantageously arranged between the two components. The components forming the channels are stacked on top of one another. At the ends of the channels, the components are preferably designed to widen the channels in such a way that, on the one hand, an intermediate space for the coolant is created between the components and, on the other hand, the intermediate space is sealed off from the exhaust gas.

The exhaust gas heat exchanger can be designed with two-stage cooling, in particular on the coolant side.

A further advantageous embodiment of the invention is that the compressor is designed as a radial compressor with a compressor wheel. The compressor wheel is arranged within the second housing element and is mechanically coupled to a drive via a drive shaft. The drive shaft protrudes through a bearing element into the second housing element and is arranged so that it can rotate about an axis of rotation via the bearing element.

According to a further development of the invention, a bypass channel is designed to separate at least a portion of the mass flow of the exhaust gas, which extends from the inlet of the exhaust gas into the housing to the outlet from the housing. At least part of the mass flow of the exhaust gas can thus be routed around the exhaust gas heat exchanger and the compressor.

According to a preferred embodiment of the invention, a bypass channel is formed for separating at least a portion of the mass flow of the exhaust gas, which extends from the inlet of the exhaust gas into the housing to the inlet of the compressor.

According to a further advantageous embodiment of the invention, a bypass channel for separating at least a portion of the mass flow of the exhaust gas is formed, which extends from the outlet of the compressor to the outlet from the housing.

At least a portion of the mass flow of the exhaust gas can thus be routed around at least a partial area of the exhaust gas heat exchanger.

The bypass channels are preferably each formed with a bypass valve for opening and closing the respective bypass channel, so that the proportion of the mass flow of the exhaust gas through the associated bypass channel can be adjusted.

According to a further advantageous embodiment of the second device according to the invention, the housing has cooling channels which are fluidically connected to a volume of the exhaust gas heat exchanger which is acted upon by coolant. The cooling channels extend into the housing element of the compressor for cooling the compressor.

• - minimale Anzahl an Teilen und damit verbunden minimaler Bauraum, minimales Gewicht bei minimalen Kosten für Herstellung, Montage und Wartung, wobei der verringerte Einsatz von Material Ressourcen schont und ein geringeres Gewicht, welches auch das Gewicht des Kraftfahrzeugs und somit die zu bewegende Masse verringert, zu Kraftstoffeinsparung führt und den Ausstoß von Kohlendioxid verringert,
• - insbesondere die Verwendung von Aluminium als Material des Gehäuses ermöglicht Herstellungsgussverfahren mit der Integration von aufwendigen Konstruktionen des Gehäuseelementes des Verdichters beziehungsweise des Verdichterrades,
• - das innere Volumen der Vorrichtung ist geringer als das vergleichbare innere Volumen bei getrennter Ausbildung von Verdichter und Abgas-Wärmeübertrager,
• - Verbesserung der Bereitstellung von Maßnahmen zur Vermeidung der Bildung von Kondensat in Verbindung mit dem Verdichterrad, wie Abgas-Wärmeübertrager-Bypass-Funktionen, Einsatz von Heizelementen oder ähnliches,
• - Nutzen positiver thermodynamischer und verfahrenstechnischer Wechselwirkungen zwischen dem Abgas-Wärmeübertrager und dem Verdichter, wobei beispielsweise das Gehäuseelement des Verdichters mit geringem Aufwand durch den bereits vorhandenen Massenstrom des Kühlmittels gekühlt werden kann oder eine Verbesserung des Vorgangs der Wärmeübertragung und damit der Kühlleistung erreicht werden kann, indem das Verdichterrad Turbulenzen innerhalb des Massenstroms des Abgases im in Strömungsrichtung nach dem Verdichterrad angeordneten Teilbereich des Abgas-Wärmeübertragers erzeugt, sowie
• - Bereitstellen verschiedener Betriebsmodi der Abgasrückführung, um den Verbrennungsmotor effizienter, mit geringeren Emissionen und geringerem Schadstoffausstoß zu betreiben, beispielsweise führt die Erhöhung der Niederdruckrate des Abgases beim Benzinmotor von 19 % auf bis zu 30 % zur Reduzierung des Krafftstoffverbrauchs um bis zu 5 %.

The device according to the invention for recirculating exhaust gas from an internal combustion engine, in which the exhaust gas heat exchanger and the compressor are combined in one module, has various advantages in summary:

• - Minimum number of parts and the associated minimum installation space, minimum weight with minimum costs for production, assembly and maintenance, with the reduced use of material conserving resources and a lower weight, which also reduces the weight of the motor vehicle and thus the mass to be moved, leads to fuel savings and reduces carbon dioxide emissions,
• - In particular, the use of aluminum as the material of the housing enables production casting processes with the integration of complex constructions of the housing element of the compressor or the compressor wheel,
• - the inner volume of the device is smaller than the comparable inner volume with a separate design of compressor and exhaust gas heat exchanger,
• - Improvement of the provision of measures to avoid the formation of condensate in connection with the compressor wheel, such as exhaust gas heat exchanger bypass functions, use of heating elements or similar,
• - Use of positive thermodynamic and procedural interactions between the exhaust gas heat exchanger and the compressor, whereby, for example, the housing element of the compressor can be cooled with little effort by the already existing mass flow of the coolant or an improvement in the process of heat transfer and thus the cooling capacity can be achieved, in that the compressor wheel generates turbulences within the mass flow of the exhaust gas in the partial area of the exhaust gas heat exchanger arranged downstream of the compressor wheel in the direction of flow, and
• - Providing different operation modes of exhaust gas recirculation to make the internal combustion engine run more efficiently, with lower emissions and lower pollutant emissions, for example, increasing the low pressure rate of the exhaust gas in the gasoline engine from 19% to up to 30% leads to a reduction in fuel consumption by up to 5%.

• 1: System zur Führung von Luft eines Verbrennungsmotors aus dem Stand der Technik,
• 2: von Abgas einflutig durchströmter Abgas-Wärmeübertrager aus dem Stand der Technik,
• 3: von Abgas zweiflutig durchströmter Abgas-Wärmeübertrager aus dem Stand der Technik,
• 4: Verdichter zum Fördern eines Massenstroms des Abgases aus dem Stand der Technik,
• 5: Vorrichtung mit einem von Abgas einflutig durchströmten Abgas-Wärmeübertrager mit integriertem Verdichter,
• 6: Vorrichtung mit einem von Abgas einflutig durchströmten Abgas-Wärmeübertrager mit integriertem Verdichter und Bypasskanal für den Massenstrom des Abgases,
• 7: Vorrichtung mit einem von Abgas zweiflutig durchströmten Abgas-Wärmeübertrager mit integriertem Verdichter und optional ausgebildeten Bypässen,
• 8: Vorrichtung mit einem von Abgas zweiflutig durchströmten Abgas-Wärmeübertrager mit integriertem Verdichter und optional ausgebildeten Bypässen sowie zweistufiger Kühlung,
• 9: Vorrichtung mit einem von Abgas zweiflutig durchströmten Abgas-Wärmeübertrager in symmetrischer Anordnung mit integriertem Verdichter und optional ausgebildeten Bypässen,
• 10: Vorrichtung mit einem von Abgas zweiflutig durchströmten Abgas-Wärmeübertrager in symmetrischer Anordnung mit integriertem Verdichter und optional ausgebildeten Bypässen sowie zweistufiger Kühlung und
• 11: Vorrichtung mit einem von Abgas einflutig durchströmten Abgas-Wärmeübertrager mit integriertem Verdichter aus einem geteilten Gehäuseelement des Abgas-Wärmeübertragers.

Further details, features and advantages of embodiments of the invention result from the following description of exemplary embodiments with reference to the associated drawings. Show it:

• 1 : system for guiding air of an internal combustion engine from the prior art,
• 2 : State-of-the-art exhaust gas heat exchanger through which exhaust gas flows in a single flow,
• 3 : State-of-the-art exhaust gas heat exchanger through which exhaust gas flows in two flows,
• 4 : Compressor for conveying a mass flow of the exhaust gas from the prior art,
• 5 : Device with an exhaust gas heat exchanger through which exhaust gas flows in a single flow with an integrated compressor,
• 6 : Device with an exhaust gas heat exchanger through which exhaust gas flows in a single flow, with an integrated compressor and bypass channel for the mass flow of the exhaust gas,
• 7 : Device with an exhaust gas heat exchanger through which exhaust gas flows in two flows, with an integrated compressor and optionally designed bypasses,
• 8th : Device with an exhaust gas heat exchanger, through which exhaust gas flows in two flows, with an integrated compressor and optionally designed bypasses as well as two-stage cooling,
• 9 : Device with an exhaust gas heat exchanger through which exhaust gas flows in two flows in a symmetrical arrangement with an integrated compressor and optionally configured bypasses,
• 10 : Device with an exhaust gas heat exchanger through which exhaust gas flows in two flows in a symmetrical arrangement with an integrated compressor and optionally designed bypasses as well as two-stage cooling and
• 11 Apparatus with an exhaust gas heat exchanger through which exhaust gas flows in a single flow, with an integrated compressor made from a divided housing element of the exhaust gas heat exchanger.

In 1 a system 1 for guiding air of an internal combustion engine 3 with arrangements 2a, 2b for recirculating exhaust gas from the prior art is shown.

The system 1 has an intake line 8 for intake of combustion air for the internal combustion engine 3 . Fresh air from the environment is drawn in through the intake line 8 via the compressor side of a turbocharger 5 in the direction of flow 9 . The compressed air is routed to the internal combustion engine 3 via an intercooler 10 and distributed to the individual cylinders. The exhaust gas generated during combustion is discharged through the exhaust pipe 4 via the turbine side of the turbocharger 5. The turbine side and the compressor side of the turbocharger 5 are mechanically coupled, for example via a shaft, so that the turbine drives the compressor and the air throughput is increased or the intake work of the pistons of the internal combustion engine 3 is reduced. The turbocharger 5 therefore obtains the energy for compressing the intake air from the residual pressure of the exhaust gases. The exhaust gas is discharged into the environment in the direction of flow 7 of the exhaust gas after it has passed the turbine side of the turbocharger 5 and devices 6a, 6b for after-treatment of the exhaust gas.

The exhaust pipe 4 and the intake pipe 8 are fluidically connected to one another via arrangements 2a, 2b for recirculating exhaust gas, the first arrangement 2a for exhaust gas recirculation being operable in the high-pressure range and the second arrangement 2b for exhaust gas recirculation being operable in the low-pressure range.

The first arrangement 2a connects the exhaust pipe 4 in the direction of flow 7 of the mass flow of the exhaust gas before the turbine side of the turbocharger 5 with the intake pipe 8 in the direction of flow 9 of the intake air mass flow after the intercooler 10 and thus after the compressor side of the turbocharger 5. The second arrangement 2b connects the Exhaust pipe 4 in the flow direction 7 of the mass flow of the exhaust gas after the turbine side of the turbocharger 5 with the intake pipe 8 in the flow direction 9 of the intake air mass flow before the compressor side of the turbocharger 5.

The arrangements 2a, 2b each consist of an exhaust gas heat exchanger 11'a, 11'b for exhaust gas cooling, a compressor 12'a, 12'b for promoting the mass flow of the exhaust gas and a valve 14'a, 14'b for controlling the Amount and thus formed the dosage of the recirculated mass flow of the exhaust gas. The compressors 12'a, 12'b are each mechanically coupled via a shaft to a drive 13'a, 13'b. The drives 13'a, 13'b are preferably designed as electric motors.

With the arrangement 2b for recirculating exhaust gas in the low-pressure range, higher exhaust gas rates can be achieved on the one hand, but on the other hand the pressure drop within the exhaust gas line 4 and the intake line 8 is low, so that additional components must be used to increase the pressure drop. The arrangement 2b for recirculating exhaust gas in the low-pressure area also enables the recirculation of clean exhaust gas, since the exhaust gas is removed in flow direction 7 after a device 6a for after-treatment of the exhaust gas, for example a particle filter in a diesel-powered internal combustion engine 3. The arrangement 2a for recirculating exhaust gas in the high-pressure range has a significantly higher dynamic, but is limited with regard to the achievable exhaust gas rates in order to ensure that the turbine side of the turbocharger 5 is supplied with sufficient exhaust gas.

2 shows an exhaust gas heat exchanger 11'a, 11'b, through which exhaust gas flows in a single flow, of an arrangement 2a, 2b for recirculating exhaust gas from the prior art. The exhaust gas heat exchanger 11'a, 11'b is used in conjunction with the internal combustion engine 3 to cool the circulating exhaust gas.

The exhaust gas enters the exhaust gas heat exchanger 11'a, 11'b in the direction of flow 7 through an inlet 21' and is divided into individual channels 24' within the inlet 21' designed as an inlet funnel. The tubes forming the channels 24' are mounted in carrier plates 23'. The support plates 23' thus serve as tube sheets. The exhaust gas flows parallel and in a flow direction 7 through the channels 24' and thus on the inside of the tubes. At the exit from the channels 24', the exhaust gas is collected in an outlet 22' of the exhaust gas heat exchanger 11'a, 11'b and is discharged through the outlet 22', which is designed as an outlet funnel, from the exhaust gas heat exchanger 11'a, 11'b.

A coolant flows around the outside of the tubes forming the channels 24'. The coolant flows in an intermediate space formed by a housing 20' and the tubes. The housing 20' enclosing the tubes and the intermediate space has an inlet 25' and an outlet 26' for the coolant which flows in the flow direction 27' through the intermediate spaces. The spaces are defined by the housing 20', the tubes and the support plates 23'.

In 3 an exhaust gas heat exchanger 11'a, 11'b, through which exhaust gas flows in two flows, of an arrangement 2a, 2b for recirculating exhaust gas from the prior art is shown. In contrast to the embodiment according to 2 the exhaust gas heat exchanger 11'a, 11'b is acted upon in such a way that the exhaust gas flows in parallel through the channels 24', the flow direction of the exhaust gas within the first flow being opposite to the flow direction within the second flow. The channels 24' are divided such that a first number of channels 24', i.e. at least one channel 24', forms a running exhaust gas route as the first flow, while a second number of channels 24', i.e. in turn at least one channel 24', forms a returning exhaust line forms as a second flood.

The exhaust gas enters the exhaust gas heat exchanger 11'a, 11'b through an inlet 21', is divided between the first channels 24' and flows in parallel and in a flow direction 7 through the first channels 24'. At the outlet of the first channels 24', the exhaust gas is collected in a deflection element 28', reversed in the direction of flow 7 and divided between the second channels 24'. The exhaust gas now flows parallel and in a flow direction 7 opposite to the flow direction through the second channels 24 ′. At the exit from the second channels 24', the exhaust gas is collected in an outlet 22' of the exhaust gas heat exchanger 11'a, 11'b and is discharged from the exhaust gas heat exchanger 11'a, 11'b. The tubes forming the channels 24' are also mounted in carrier plates 23'.

The design of the exhaust gas heat exchanger 11'a, 11'b on the coolant side corresponds to that in 2 described embodiment.

The exhaust gas heat exchangers 11'a, 11'b thus have no, one or more reversals in the direction of flow 7 of the mass flow of the exhaust gas. An exhaust gas heat exchanger 11'a, 11'b, which has no reversal of the flow direction 7 of the mass flow of the exhaust gas, according to 2 , has, is also referred to as an I-flow heat exchanger. An exhaust gas heat exchanger 11'a, 11'b with a reversal of the flow direction 7 of the mass flow of the exhaust gas, according to FIG 3 , is U-flowed through on the exhaust side. Not shown exhaust gas heat exchangers 11'a, 11'b with several reversals of the flow direction 7 of the mass flow of the exhaust gas are referred to as S-flow, W-flow or multi-flow, depending on the number of reversals and arrangement of the channels.

the end 4 a compressor 12'a, 12'b designed as a radial compressor for conveying a mass flow of the exhaust gas, also referred to as a pump, emerges from the prior art.

The compressor 12'a, 12'b has a housing 30' designed as a spiral housing with an inlet 31' and an outlet 32' for the exhaust gas. Inside the housing 30' is a driven Compressor wheel 33' arranged for conveying the exhaust gas. The compressor wheel 33' is mechanically coupled via a drive shaft 34' to a drive 13'a, 13'b, which is preferably designed as an electric motor. The compressor wheel 33' and the drive shaft 34' are arranged supported by a bearing element 35'.

The housing 30' is closed in an exhaust-tight manner by the bearing element 35' in the direction of the drive 13'a, 13'b. The drive shaft 34' protrudes from the outside through the bearing element 35' into the housing 30'.

The exhaust gas flows in the direction of flow 7 through the inlet 31' into the housing 30' and axially into the compressor wheel 33' operated as an impeller. As a result of the movement of the compressor wheel 33', the energy necessary for increasing the pressure is supplied to the exhaust gas and the exhaust gas is deflected radially outwards. The flow direction 7 of the exhaust gas undergoes a change from the axial to the radial direction of approximately 90°.

5 shows a device 40a for recirculating exhaust gas as an exhaust gas heat exchanger 11, through which exhaust gas flows in a single flow, with an integrated compressor 12. The device 40a represents a combination of an exhaust gas heat exchanger 11, through which exhaust gas flows, with a compressor 12 designed as a radial compressor for conveying the mass flow of the exhaust gas.

The exhaust gas heat exchanger 11 and the compressor 12 are arranged within a common housing 41 which has two housing elements 20 , 30 . The first housing element 20 encloses the channels 24 forming tubes of the exhaust gas heat exchanger 11, while the compressor impeller 33 of the compressor 12 is arranged within the second housing element 30 .

The housing element 20 of the exhaust gas heat exchanger 11 and the housing element 30 of the compressor 12 are designed as a housing 41 and are connected thereto as one component. In this case, the housing 41 is formed from the housing elements 20, 30 either as a one-piece component or as a connected component in such a way that the housing 41 forms a unit. A one-piece component means that the housing 41 is made of one material without additional connection points. The housing 41 assembled into a connected component from the housing elements 20, 30 also forms an exhaust gas-tight unit, the individual housing elements 20, 30 being connected to one another with a material connection, for example by soldering or welding, or with a positive or non-positive fit, for example by screwing, clipping or crimping are.

The exhaust gas flows in the direction of flow 7 through the inlet 21 into the housing element 20 of the exhaust gas heat exchanger 11 and is divided into the individual channels 24 forming tubes within the inlet 21 designed as an inlet funnel. The tubes are fastened in support plates 23, which are designed as tube sheets. The exhaust gas flowing parallel and in a direction of flow 7 through the ducts 24 and thus on the inside of the tubes is collected in an outlet at the outlet of the ducts 24 and conducted through the outlet designed as an outlet funnel from the exhaust gas heat exchanger 11 directly into the compressor 12. The outlet of the housing element 20 of the exhaust gas heat exchanger 11 also represents the inlet 31 of the housing element 30 of the compressor 12.

The direct transfer of the exhaust gas from the exhaust gas heat exchanger 11 to the compressor 12 should therefore be understood to mean that there are no further additional and individual or detached components of an exhaust gas line between the exhaust gas heat exchanger 11 and the compressor 12, such as devices for conducting, in particular pipes, Hoses, deflection elements or the like are provided and necessary.

The exhaust gas flowing out inside the housing 41 from the housing element 20 of the exhaust gas heat exchanger 11 and into the housing element 30 of the compressor 12 designed as a spiral housing and thus flowing over between the housing elements 20, 30 is conducted to the compressor wheel 33 arranged in the housing element 30. The driven compressor wheel 33 for conveying the exhaust gas is mechanically coupled via the drive shaft 34 to the drive 13, which is preferably designed as an electric motor. The drive shaft 34 and the compressor wheel 33 , which is firmly and rigidly connected to the drive shaft 34 , are arranged by means of the bearing element 35 in the housing element 30 of the housing 41 so as to be rotatable about an axis of rotation. The axis of rotation runs in the direction of the drive shaft 34 . With the help of the bearing element 35 , the housing 41 is sealed in the direction of the drive 13 so that it is gas-tight, with the drive shaft 34 being guided through the bearing element 35 .

The exhaust gas flows in the direction of flow 7 through the inlet 31 into the housing element 30 of the compressor 12, which is designed as a volute housing, and hits the compressor wheel 33, which is operated as an impeller, in the axial direction. When passing through the compressor wheel 33, the pressure of the exhaust gas is increased and the exhaust gas flows radially guided outside and then discharged through the outlet 32 from the housing 41.

A valve (not shown) is assigned to device 40a as a partial component of an arrangement for recirculating the exhaust gas, the valve being arranged alternatively before or after device 40a in the flow direction of the exhaust gas. The valve, not shown, is used to regulate the quantity and thus the metering of the recirculated mass flow of the exhaust gas.

Coolant is applied to the tubes of the exhaust gas heat exchanger 11 on the outside, with the coolant being conducted in the direction of flow 27 through an intermediate space formed by the housing 41 and the tubes. The space is enclosed by the housing 41, the tubes and the support plates 23 of the tubes. The housing 41 comprising the tubes and the gap has the inlet 25 and the outlet 26 for the coolant, which are arranged such that the coolant and the exhaust gas flow essentially in cross-countercurrent to one another.

In 6 a device 40b for recirculating exhaust gas is shown as an exhaust gas heat exchanger 11 through which exhaust gas flows in a single flow, with an integrated compressor 12 and a bypass channel 42 for the mass flow of the exhaust gas. The device 40b essentially corresponds to the device 40a as an embodiment 5 with an additional bypass channel 42 and a bypass valve 43.

The bypass channel 42 extends from the inlet 21 into the housing element 20 in the exhaust gas heat exchanger 11 to the outlet of the exhaust gas from the exhaust gas heat exchanger 11, which likewise represents the inlet 31 of the exhaust gas into the compressor 12. The bypass duct 42 branches off from the inlet funnel for dividing the mass flow of the exhaust gas to the individual ducts 24 and opens out at the transition region of the housing elements 20, 30. The bypass duct 42 consequently serves to separate at least a portion of the mass flow of the exhaust gas, which flows around the exhaust gas heat exchanger 11 is bypassed and thus experiences no heat transfer with the coolant. The mass flow of the exhaust gas conducted through the bypass channel 42 is consequently not cooled and is conducted directly to the compressor 12 . Depending on the division of the mass flow of the exhaust gas into a portion flowing through the bypass channel 42 and a portion flowing through the exhaust gas heat exchanger 11 , both portions are mixed again at the inlet 31 of the exhaust gas into the compressor 12 .

In the area where the bypass channel 42 branches off from the inlet 21 , the bypass channel 42 is configured with a bypass valve 43 for opening and closing the bypass channel 42 . According to alternative embodiments that are not shown, the bypass valve can be arranged at any point in the bypass channel so that it can be closed.

With the degree of opening of the bypass valve 43, the quantity and thus the metering of the mass flow of the exhaust gas conducted around the exhaust gas heat exchanger 11 and thus the ratio of the proportions of the mass flows through the exhaust gas heat exchanger 11 and through the bypass channel 42 are set.

the 7 until 10 each show a device 40c, 40d, 40e, 40f for recirculating exhaust gas as an exhaust gas heat exchanger 11 through which exhaust gas flows in two flows, with an integrated compressor 12 and optionally configured bypass channels 47, 49 for at least a portion of the mass flow of the exhaust gas. The devices 40c, 40d, 40e, 40f are in turn each a combination of an exhaust gas heat exchanger 11, through which exhaust gas flows, with a compressor 12 designed as a radial compressor for conveying the mass flow of the exhaust gas.

The exhaust gas heat exchanger 11 and the compressor 12 are arranged in a common housing 41 having two housing elements 20, 30, the first housing element 20 enclosing the channels 24 of the exhaust gas heat exchanger 11 and the second housing element 30 enclosing the compressor wheel 33 of the compressor 12.

The exhaust gas flows through the inlet 21 into the housing element 20 of the exhaust gas heat exchanger 11 and is divided within the inlet 21 to the individual channels 24 which are arranged as tubes fastened in support plates 23 . The exhaust gas heat exchanger 11 is acted upon by the exhaust gas in such a way that the exhaust gas flows parallel through the channels 24, the flow direction of the exhaust gas within the first flow being opposite to the flow direction within the second flow. A first number of channels 24, ie at least one channel 24, forms a forward exhaust gas line as the first flow, while a second number of channels 24, that is also at least one channel 24, forms a return exhaust gas line as the second flow.

At the outlet of the first channels 24, the exhaust gas flowing through the channels 24 and thus on the inside of the tubes is collected and introduced directly into the housing element 30 of the compressor 12, which is designed as a spiral housing. The outlet of the first channels 24 of the exhaust gas heat exchanger 11 likewise provides the inlet 31 of the housing element 30 to the compressor wheel 33 of the compressor ters 12. In this way, the exhaust gas flowing over between the housing elements 20, 30 is fed to the compressor wheel 33 arranged in the housing element 30. As in the previous embodiments, the compressor wheel 33 is driven via the drive shaft 34 and is mechanically connected to the drive 13, the drive shaft 34 being arranged in the housing element 30 of the housing 41 so as to be rotatable about an axis of rotation by means of the bearing element 35.

The exhaust gas flows in the direction of flow 7 through the inlet 31 into the housing element 30 of the compressor 12 designed as a spiral housing and in the axial direction into the compressor wheel 33 , is guided radially outwards and discharged through the outlet 32 into an exhaust gas duct 44 . The exhaust passage 44 is formed inside the case member 30 .

When flowing through the compressor 12 and the exhaust gas duct 44, the direction of flow 7 of the exhaust gas is reversed in relation to the direction of flow within the outgoing exhaust gas section. The exhaust gas is divided between the second ducts 24 and now flows parallel and in the flow direction 7 of the exhaust gas within the incoming exhaust gas line in the opposite flow direction through the second ducts 24 of the returning exhaust gas line. At the exit from the second channels 24 the exhaust gas is collected in an outlet 22 of the exhaust gas heat exchanger 11 and discharged from the exhaust gas heat exchanger 11 .

Compared to the embodiment according to 3 the deflection element 28' of the exhaust gas heat exchanger 11'a, 11'b, which deflects the flow direction 7 of the exhaust gas by 180°, is replaced by the compressor 12 with the housing element 30. The housing element 30 of the compressor 12 now causes the direction of flow 7 of the exhaust gas to be deflected by 180°.

The tubes forming the ducts 24 are arranged in connection with the design of the housing 41, in particular the housing element 30 of the compressor 12, in such a way that the ducts 24 of the incoming exhaust gas line are combined in a separate area from the channels 24 of the return exhaust gas line in a further area are. The areas of the channels 24 of the outgoing and the returning exhaust gas line of the devices 40c, 40d are after 7 and 8th next to each other, in particular above or below and thus separated from one another.

The housing element 30 of the compressor 12 of the devices 40e, 40f according to 9 and 10 is designed in comparison to the devices 40c, 40d in such a way that the areas of the channels 24 of the incoming and the returning exhaust gas path are arranged symmetrically, so that the housing elements 20, 30 of the exhaust gas heat exchanger 11 and the compressor 12 can be designed essentially symmetrically. The pipes forming the channels 24 of the incoming exhaust gas line are arranged in the center and the pipes forming the channels 24 of the returning exhaust gas line are arranged concentrically around the pipes forming the channels 24 of the incoming exhaust gas line. The pipes of the return exhaust gas line are arranged in their entirety coaxially around the pipes of the incoming exhaust gas line.

The coolant-side design of the exhaust gas heat exchanger 11 of the device 40c 7 and device 40e 9 corresponds to the in 3 described embodiment.

The coolant sides of the exhaust gas heat exchanger 11 of the device 40d after 8th and device 40f 10 are each designed for a two-stage cooling of the exhaust gas. The pipes forming the channels 24 of the outgoing exhaust gas line and the returning exhaust gas line are surrounded by separate coolant-carrying housing parts. The pipes forming the channels 24 of the incoming exhaust gas line are surrounded by a volume 45 for a first coolant circuit and the pipes forming the channels 24 of the returning exhaust gas line are surrounded by a volume 46 for a second coolant circuit, which are each formed by the coolant-carrying housing parts.

The volumes 45, 46 for the coolant circuits of the incoming and the returning exhaust gas line of the devices 40c, 40d according to 7 and 8th enclosing coolant-carrying housing parts are arranged side by side, in particular above or below each other.

The volumes 45, 46 for the coolant circuits of the incoming and the returning exhaust line of the devices 40e, 40f according to 9 and 10 enclosing coolant-carrying housing parts are arranged concentrically to one another, in particular coaxially to one another, in accordance with the associated pipes.

The devices 40c, 40d, 40e, 40f can also be designed with different bypass channels 47, 49, 51 and associated bypass valves 48, 50, 52 for the mass flow of the exhaust gas.

A first bypass duct 47 extends from the inlet 21 into the housing element 20 in the exhaust gas heat exchanger 11 to the outlet of the exhaust gas from the exhaust gas heat exchanger 11. The bypass duct 47 for dividing the mass flow of the exhaust gas is therefore for separating at least a portion of the mass flow of the Formed exhaust gas, which is routed completely around the exhaust gas heat exchanger 11 and the compressor 12, so that no heat is transferred between the mass flow of the exhaust gas conducted through the bypass channel 47 and the coolant. The mass flow of the exhaust gas conducted through the bypass channel 47 is consequently neither cooled nor compressed.

Depending on the division of the mass flow of the exhaust gas into a portion flowing through the bypass channel 47 and a portion flowing through the exhaust gas heat exchanger 11 and the compressor 12, both portions are mixed again at the outlet 22 of the exhaust gas heat exchanger 11. The metering of the mass flow of the exhaust gas conducted around the exhaust gas heat exchanger 11 and thus the ratio of the proportions of the mass flows through the exhaust gas heat exchanger 11 and through the bypass channel 47 is adjusted with the degree of opening of the bypass valve 48 formed in the bypass channel 47.

A second bypass duct 49 extends from the inlet 21 into the housing element 20 of the exhaust gas heat exchanger 11 to the inlet 31 of the compressor 12 and opens out at the transition region of the housing elements 20, 30. The bypass duct 49 is therefore designed to separate at least a portion of the mass flow of the exhaust gas , which is routed around the first channels 24 of the outgoing exhaust gas section of the exhaust gas heat exchanger 11 . Thus, at least in the region of the outgoing exhaust gas section, as the first flow of the double-flow exhaust gas heat exchanger 11 , no heat is transferred to the coolant from the mass flow of the exhaust gas conducted through the bypass channel 49 . The mass flow of exhaust gas that is routed through the second bypass channel 49 is consequently not cooled and is routed directly to the compressor 12 . Depending on the division of the mass flow of the exhaust gas into a portion flowing through the bypass duct 49 and a portion flowing through the first ducts 24 of the exhaust gas heat exchanger 11 , both portions are mixed again at the inlet 31 of the exhaust gas into the compressor 12 .

The bypass channel 49 is formed with a bypass valve 50 for opening and closing the bypass channel 49 . The amount of the exhaust gas mass flow guided around the first flow of the exhaust gas heat exchanger 11 and thus the ratio of the proportions of the mass flows through the first flow and through the bypass channel 49 are set via the degree of opening of the bypass valve 50 .

A third bypass duct 51 extends from the outlet 32 of the compressor 12 or from the exhaust gas duct 44 of the housing element 30 to the outlet 22 of the housing element 20 of the exhaust gas heat exchanger 11. The bypass duct 51 is thus designed to separate at least part of the mass flow of the exhaust gas, which the second channels 24 of the returning exhaust gas section of the exhaust gas heat exchanger 11 is bypassed. Thus, at least in the area of the returning exhaust gas line as the second flow of the double-flow exhaust gas heat exchanger 11 , no heat is transferred to the coolant from the mass flow of the exhaust gas conducted through the bypass channel 51 . The mass flow of the exhaust gas conducted through the third bypass channel 51 is consequently not cooled and is conducted directly to the outlet 22 of the exhaust gas heat exchanger 11 . Depending on the division of the mass flow of the exhaust gas into a portion flowing through the bypass duct 51 and a portion flowing through the second ducts 24 of the exhaust gas heat exchanger 11 , the two portions are mixed again at the outlet 22 .

The bypass channel 51 has a bypass valve 52 for opening and closing the bypass channel 51 . By opening the bypass valve 52 , the quantity of the mass flow of the exhaust gas conducted around the second flow of the exhaust gas heat exchanger 11 and thus the ratio of the proportions of the mass flows through the second flow and through the bypass channel 51 are adjusted.

The bypass channels 47, 49, 51 can each be formed alone or in combination with one or both of the respective other bypass channels 47, 49, 51. The device 40c, 40d, 40e, 40f can be operated in different modes.

If, for example, only the bypass channel 47 is formed around the device 40c, 40d, 40e, 40f and thus the heat exchanger 11 and the compressor 12, or the bypass channels 49, 51 are each closed around a flow of the heat exchanger 11 and are therefore not active, the exhaust gas conducted around the compressor 12 and the compressor 12 is not flowed through by exhaust gas. The exhaust gas is therefore neither cooled nor compressed. The bypass channel 47 is also referred to as a direct bypass.

If one of the two bypass channels 49, 51 is formed around a flow of the heat exchanger 11 or is active, the mass flow of the exhaust gas conducted through the device 40c, 40d, 40e, 40f is either when flowing through the incoming exhaust gas section or the returning exhaust gas route cooled. In addition, the mass flow of the exhaust gas is passed through the compressor 12 and compressed. The bypass channel 47 around the device 40c, 40d, 40e, 40f can be formed and opened or closed.

If both bypass channels 49, 51 are formed around a flow of the heat exchanger 11 and are active, the mass flow of the exhaust gas conducted through the device 40c, 40d, 40e, 40f is conducted around both the incoming and the returning exhaust gas path and through the compressor 12 . The mass flow of the exhaust gas conducted through the bypass channels 49, 51 is indeed compressed, but not cooled. The bypass channel 47 around the device 40c, 40d, 40e, 40f can be formed and opened or closed.

The bypass channels 47, 49, 51 can be formed directly in the housing 41 of the device 40c, 40d, 40e, 40f, so that no separate and additional tubes and support plates have to be provided.

According to an alternative embodiment that is not shown, the second bypass channel 49 and the third bypass channel 51 can each be acted upon by coolant on the outside. According to a further alternative embodiment, not shown, the bypass channels 49, 51 have no bypass valves.

Furthermore, the housing 41 is formed with the housing elements 20, 30, in particular within the housing element 30 of the compressor 12, with additional cooling channels which are fluidically connected to the volume of the exhaust gas heat exchanger 11 acted upon by the coolant. In addition to the exhaust gas, the coolant conducted through the additional cooling channels can also be used to cool the compressor 12 in order to protect the components of the compressor 12 from overheating. The compression of the exhaust gas can lead to very high temperatures.

The devices 40c, 40d, 40e, 40f are subcomponents of an arrangement for recirculating the exhaust gas in the direction of flow 7 of the exhaust gas, a valve 14 for controlling the quantity and thus the metering of the recirculated mass flow of the exhaust gas. Alternatively, the valve can also be arranged in front of the devices 40c, 40d, 40e, 40f in the flow direction of the exhaust gas.

11 shows a device 40g with an exhaust gas heat exchanger 11, through which exhaust gas flows in a single flow, with an integrated compressor 12, which are arranged within the common housing 41. The exhaust gas heat exchanger 11 has a divided housing element 20 which is formed from a first part 20a as the upper half and a second part 20b as the lower half.

The individual parts 20a, 20b of the housing element 20 and the housing elements 20, 30 are connected to one another with a material fit, for example by soldering or welding, or with a positive or non-positive fit, for example by screwing, clipping or crimping. The parts 20a, 20b of the housing element 20 of the exhaust gas heat exchanger 11 and the housing element 30 of the compressor 12 are designed as a housing 41 and are connected thereto as one component.

The exhaust gas flowing in the direction of flow 7 through the inlet 21 into the housing element 20 is divided into the individual channels 24 within the inlet 21, as is also the case in the embodiment according to FIG 5 emerges. For further details, refer in particular to the statements 5 referred.

In contrast to the embodiment according to 5 the channels 24 for conducting the exhaust gas are formed between a first plate member and a second plate member. Elements for increasing the surface area, such as corrugated ribs or ribs with similar geometries, are arranged between the two plate elements on the exhaust gas side. The plate elements forming the channels 24 are stacked one on top of the other, with a second plate element lying against a first plate element and an intermediate space for the coolant being formed between the plate elements as an upper and a lower boundary. At the ends of the channels 24, the plate elements are designed to widen the flow cross section of the channels 24 in such a way that the intermediate space existing between the plate elements is sealed off from the exhaust gas. The coolant is conducted in the direction of flow 27 through the intermediate space formed by the housing 41 and the plate elements.

Reference List

1

System for guiding air

2a, 2b

Arrangement for recirculating exhaust gas

3

combustion engine

4

exhaust pipe

5

turbocharger

6a, 6b

Device for after-treatment of the exhaust gas

7

Direction of flow Mass flow of the exhaust gas

8th

intake line

9

Air mass flow drawn in in the direction of flow

10

intercooler

11, 11'a, 11'b

exhaust gas heat exchanger

12, 12'a, 12'b

compressor

13, 13'a, 13'b

drive

14, 14'a, 14'b

Valve

20

Housing element exhaust gas heat exchanger 11

20a

first part housing element 20

20b

second part housing element 20

20'

Housing exhaust gas heat exchanger 11'a, 11'b

21, 21'

Inlet exhaust gas heat exchanger 11, 11'a, 11'b

22, 22'

Outlet exhaust gas heat exchanger 11, 11'a, 11'b

23, 23'

backing plate

24, 24'

Channel mass flow of exhaust gas

25, 25'

inlet coolant

26, 26'

outlet coolant

27, 27'

Flow direction coolant mass flow

28'

deflection element

30

Housing element compressor 12

30'

Housing compressor 12'a, 12'b

31, 31'

Inlet exhaust gas compressor 12, 12'a, 12'b

32, 32'

Outlet exhaust gas compressor 12, 12'a, 12'b

33, 33'

compressor wheel

34, 34'

drive shaft

35, 35'

bearing element

40a, 40b, 40c, 40d, 40e, 40f, 40g

Exhaust gas recirculation device

41

housing of the device

42

Bypass duct around heat exchanger 11

43

Bypass valve bypass channel 42

44

exhaust duct

45

Volume of first coolant circuit

46

Second coolant circuit volume

47

Bypass channel around device 40c, 40d, 40e, 40f

48

Bypass valve bypass channel 47

49, 51

Bypass channel around a flood of the heat exchanger 11

50, 52

Bypass valve bypass channel 49, 51

Claims (12)

Device (40a, 40b, 40c, 40d, 40e, 40f) for recirculating exhaust gas from an internal combustion engine (3) in a motor vehicle, having - an exhaust gas heat exchanger (11) which is connected to a first housing element (20) with an inlet (21 ) and an outlet (22) for the exhaust gas and at least one inlet (25) and at least one outlet (26) for a coolant, and - a compressor (12) which is provided with a second housing element (30) with an inlet ( 31) and an outlet (32) for the exhaust gas, wherein the first housing element (20) of the exhaust gas heat exchanger (11) and the second housing element (30) of the compressor (12) form a housing (41) to form a coherent, are connected to a compact component, so that the exhaust gas heat exchanger (11) and the compressor (12) are arranged within the housing (41), characterized in that the housing (41) has cooling ducts which fluidically have a volume charged with coolant of the exhaust gas heat exchanger (11) and extend into the housing element (30) of the compressor (12) for cooling the compressor (12). Device (40a, 40b, 40c, 40d, 40e, 40f) according to claim 1 , characterized in that the compressor (12) is arranged in the flow direction (7) of the exhaust gas after the exhaust gas heat exchanger (11) or in the case of a multi-flow design of the exhaust gas heat exchanger (11) between two flows of the exhaust gas heat exchanger (11). Device (40a, 40b, 40c, 40d, 40e, 40f) for recirculating exhaust gas from an internal combustion engine (3) in a motor vehicle, having - an exhaust gas heat exchanger (11) which is connected to a first housing element (20) with an inlet (21 ) and an outlet (22) for the exhaust gas and at least one inlet (25) and at least one outlet (26) for a coolant, and - a compressor (12) which is provided with a second housing element (30) with an inlet ( 31) and an outlet (32) for the exhaust gas, wherein the first housing element (20) of the exhaust gas heat exchanger (11) and the second housing element (30) of the compressor (12) form a housing (41) to form a coherent, are designed to be connected to a compact component, so that the exhaust gas heat exchanger (11) and the compressor (12) are arranged within the housing (41), characterized in that the exhaust gas heat exchanger (11) is designed with multiple flows and the compressor (12) in flow direction direction (7) of the exhaust gas between two flows of the exhaust gas heat exchanger (11) is arranged. Device (40c, 40d, 40e, 40f) according to claim 3 , characterized in that the exhaust gas heat exchanger (11) is designed with two flows, with at least one duct (24) forming a running exhaust gas section as the first flow and at least one duct (24) forming a returning exhaust gas section as the second flow and the compressor (12) is arranged in the flow direction of the exhaust gas between the first flood and the second flood. Device (40a, 40b, 40c, 40d, 40e, 40f) according to one of claims 2 until 4 , characterized in that in the area of the exhaust gas heat exchanger (11) channels (24) are formed for conducting the exhaust gas, which run from the inlet (21) of the exhaust gas heat exchanger (11) to the inlet (31) of the compressor (12) extend, wherein the exhaust gas exiting from the channels (24) is collected in the region of the inlet (31) of the compressor (12) and fed directly into the compressor (12). Device (40a, 40b, 40c, 40d, 40e, 40f) according to one of Claims 1 until 5 , characterized in that the housing (41) with the first housing member (20) and the second housing member (30) is formed as a one-piece component from one material. Device (40a, 40b, 40c, 40d, 40e, 40f) according to one of Claims 1 until 6 , characterized in that the compressor (12) is designed as a radial compressor with a compressor wheel (33), the compressor wheel (33) being arranged within the housing element (30) and being mechanically coupled to a drive (13) via a drive shaft (34). , wherein the drive shaft (34) protrudes through a bearing element (35) into the housing element (30) and is arranged with the bearing element (35) so as to be rotatably mounted about an axis of rotation. Device (40c, 40d, 40e, 40f) according to one of Claims 1 until 7 , characterized in that a bypass channel (47) is designed to separate at least a portion of the mass flow of the exhaust gas, which extends from the inlet into the housing (41) to the outlet from the housing (41), so that at least the portion of the mass flow of the exhaust gas can be guided around the exhaust gas heat exchanger (11) and the compressor (12). Device (40b, 40c, 40d, 40e, 40f) according to one of claims 2 until 8th , characterized in that a bypass channel (42, 49) is designed to separate at least a portion of the mass flow of the exhaust gas, which extends from the inlet into the housing (41) to the inlet (31) of the compressor (12), so that at least the portion of the mass flow of the exhaust gas can be guided around at least a partial area of the exhaust gas heat exchanger (11). Device (40c, 40d, 40e, 40f) according to one of claims 2 until 9 , characterized in that a bypass channel (51) is designed to separate at least a portion of the mass flow of the exhaust gas, which extends from the outlet (32) of the compressor (12) to the outlet from the housing (41), so that at least the portion of the mass flow of the exhaust gas can be guided around at least a partial area of the exhaust gas heat exchanger (11). Device (40b, 40c, 40d, 40e, 40f) according to one of Claims 8 until 10 , characterized in that the bypass channel (42, 47, 49, 51) is formed with a bypass valve (43, 48, 50, 52) for opening and closing the bypass channel (42, 47, 49, 51), so that the proportion of Mass flow of the exhaust gas through the bypass channel (42, 47, 49, 51) is adjustable. Device (40a, 40b, 40c, 40d, 40e, 40f) according to one of claims 3 until 11 , characterized in that the housing (41) Kühlka has channels which are fluidically connected to a volume of the exhaust gas heat exchanger (11) acted upon by coolant and extend into the housing element (30) of the compressor (12) for cooling the compressor (12).

Images