WO2013079427A1

WO2013079427A1 - Internal combustion engine with an arrangement for feeding back exhaust gas and supplying cooled charge air

Info

Publication number: WO2013079427A1
Application number: PCT/EP2012/073564
Authority: WO
Inventors: Christian BÜCKER; Peter Geskes; Detlef Jacobi; Andreas Kleber; Rainer Lutz; Uwe Mohr; Rolf Müller; Eberhard Pantow; Nic Sautter; Hartmut Sauter
Original assignee: Behr Gmbh & Co. Kg; Mahle International Gmbh
Priority date: 2011-11-28
Filing date: 2012-11-26
Publication date: 2013-06-06
Also published as: CN204175395U; EP2785992A1; DE102011087256A1

Abstract

The invention relates to an internal combustion engine (1): with an arrangement for feeding back exhaust gas and supplying cooled charge air to an internal combustion engine (1), wherein the internal combustion engine (1) comprises an exhaust gas supercharging system (6, 7) and an exhaust gas cooling system (16); with an exhaust gas cooling system (16) having a single or double stage exhaust gas cooler with a first cooling stage (20) and optionally a second cooling stage (21); with at least one bypass (17) for circumventing the first and/or the second cooling stage of the exhaust gas cooler (16); with at least one exhaust gas control valve (15); with at least one intercooler (25) and a bypass (30) for circumventing the first intercooler (25); and with a charge air control valve (28), wherein the components of the arrangement that come into contact with an acidic condensate produced in the exhaust gas cooler (16) and/or in the intercooler (25) previously undergo an immunising treatment such that they resist the condensate.

Description

Internal combustion engine with an arrangement for the return of exhaust gas and

Supply of cooled charge air Description Technical field

The invention relates to an internal combustion engine having an arrangement for recirculating exhaust gas and supplying cooled charge air, wherein the internal combustion engine has an exhaust gas charging and an exhaust gas cooling system, in particular according to the preamble of claim 1.

State of the art

Internal combustion engines with an arrangement for the return of exhaust gas and for the supply of cooled charge air are widely known in the art. Thus, by the application DE 10 2008 045 479 A1 a system has become known for the return of exhaust gas of an internal combustion engine, the internal combustion engine having an exhaust system with a high pressure and a low pressure part, the system having a separator which is adapted to a from Exhaust gas of the high pressure part of the exhaust system to separate a condensate and to introduce the condensate via a discharge line in the low pressure part of the exhaust system to divert it from there the exhaust system. The generation of a condensate in internal combustion engines with exhaust systems or charge air systems is thus known as a disadvantageous effect in such devices in certain operating states. The condensate is an acidic condensate at about pH 1 to 2, which contains, inter alia, sulfuric and nitric acid, and that due to its aggressive acidic properties to increased corrosion of the components of the arrangement for recirculation of exhaust gas and the supply of cooled charge air an internal combustion engine leads.

According to DE 10 2008 045 479 A1, this condensate is separated by a separator from the recirculated exhaust gas and fed to the low pressure side of the exhaust gas system after an exhaust aftertreatment unit in the exhaust pipe to get from there into the environment.

This has the disadvantage, in particular for the internal combustion engine and its components, that the condensate in the region of the exhaust gas cooler basically arises in certain operating states and can there already lead to increased corrosion before it is separated and discharged.

Document DE 10 2005 008 103 A1 discloses an exhaust-gas turbocharger internal combustion engine in which exhaust gas recirculation is carried out at the rear, the exhaust-gas turbocharger internal combustion engine having a condensate collecting and / or discharging device in order to collect and remove the resulting condensate from the exhaust gas heat exchanger. Again, the condensate is formed in the exhaust gas heat exchanger and leads there to increased corrosion. The publication DE 10 2005 023 958 A1 also discloses a turbocharger arrangement in which a condensate is formed in the exhaust gas cooler, wherein The condensate is disposed of by means of a condensate separator and a downstream thermal condensate disposal, so that the acids contained in the condensate are preferably converted into their harmless gases and water.

AH the listed documents can in the exhaust gas cooler to that a condensate is produced, which leads to increased corrosion of the components of the internal combustion engine.

Presentation of the invention, object, solution, advantages

It is the object of the invention to provide an internal combustion engine with an arrangement for the return of exhaust gas and for supplying cooled charge air, which despite a generation of acidic condensate is nonetheless durable.

The object is achieved with the features of claim 1, according to which an internal combustion engine with an arrangement for recirculating exhaust gas and supplying cooled charge air to the internal combustion engine is provided, wherein the internal combustion engine has an exhaust gas charging system and an exhaust gas cooling system, with an exhaust gas cooling system having a or two-stage exhaust gas cooler with a first cooling stage and optionally with a second cooling stage, with at least one bypass to bypass the first and / or second cooling stage of the exhaust gas cooler and at least one exhaust control valve, with at least a first charge air cooler and a bypass to bypass the first charge air cooler and with a charge air control valve, wherein components of the arrangement and / or the internal combustion engine, which come into contact with an acid condensate preferably generated in the exhaust gas cooler and / or in the intercooler, such are designed or treated to withstand the acid condensate.

It is advantageous if these are components, such as the exhaust valve and / or exhaust gas recirculation valve, the exhaust gas cooler, the first and / or the second cooling stage of the exhaust gas cooler, the intercooler in the high pressure region, the intercooler in the low pressure region, the intake or the intake , the intake valve or the intake valves of the internal combustion engine, the valve guide of the intake valve, the valve seat ring of the intake valve, the head gasket of the cylinder head, the cylinder surface of the cylinder of the internal combustion engine, the piston or the piston rings, the annular groove of the piston, the Exhaust flap, the turbocharger or the turbocharger, the exhaust duct and / or the exhaust filter. It is also advantageous if the training or treatment for the immunization of the components in particular by the type of choice of material, the type of coating, the type of chrome plating, the type of chromium plating, the type of PVD coating. Further advantageous embodiments are described by the following description of the figures and by the subclaims.

Brief description of the drawings

The invention will be explained in more detail on the basis of at least one embodiment with reference to the drawings. Show it:

Fig. 1 shows an embodiment of an inventive

Internal combustion engine with an arrangement for the return of exhaust gas and for supplying cooled charge air. Preferred _. Embodiment of the invention

1 shows an internal combustion engine with an arrangement for the return of exhaust gas and for supplying cooled charge air to the internal combustion engine 1, which is shown schematically. Here, the internal combustion engine 1 is shown as a multi-cylinder internal combustion engine with a plurality of cylinders 2, wherein this can be done without limiting the generality with any number of cylinders.

The internal combustion engine 1 is supplied with the air for the combustion of the fuel via a suction module 3 to the respective cylinders 2, said suction module 3 distributes the air to the cylinder 2 in accordance with the requirements of the respective operating state. The exhaust gas from the cylinders 2 is collected via an exhaust manifold 4 and discharged via an exhaust pipe 5.

In this case, the exhaust gas is fed to a two-stage charging arrangement. The two-stage charging arrangement is represented by two turbochargers 6, 7, wherein the exhaust gas from the exhaust gas outlet line 5 is directed to a first turbine 8 of the first turbocharger 6 and from there via the connecting line 9 to a second turbine 10 of the second turbocharger 7 on , Starting from the turbine 10, the exhaust gas is supplied via the line 1 1 an optional particulate filter or other aftertreatment device 12 and fed from there to an outlet 13, from where it is discharged, for example by a muffler of the motor vehicle into the environment.

In addition to a discharge of the exhaust gas via the lines 5 and the following turbochargers 6, 7 to the line 13 can also be carried out a return of exhaust gas via the line 14 to the engine. In this case, the exhaust gas from the exhaust manifold 4 is fed into the line 14, passed through a correspondingly existing valve 15 and returned via an exhaust heat exchanger 16 to the intake manifold 3 of the internal combustion engine. Parallel to the exhaust gas heat exchanger 16, a bypass line 1 7 is further provided, through which also exhaust gas can flow. This exhaust gas is in turn fed to the intake manifold 3. The distribution of the amount of exhaust gas which flows through the exhaust gas cooler 16 or flows through the bypass 17, is effected by the control of the valve 15, thereby possibly simultaneously the total amount of recirculated exhaust gas can be controlled as well as their distribution to the exhaust gas heat exchanger 16 and to the bypass 17. Thus, the valve 15 can not only control the distribution of the exhaust gas between the heat exchanger and the bypass, but also adjust the total amount of recirculated exhaust gas, which can be done depending on the operating state via an electronic control. The valve 15 can be advantageously designed as an integrated valve with the realization of the two functions. Alternatively, it can also be realized by two individual valves, a valve which adjusts the amount of exhaust gas flowing through, and a valve which controls the division between the flow of the heat exchanger 16 and the flow through the bypass 17.

At the output of the heat exchanger 16 may be provided for control of an unillustrated temperature sensor, which may advantageously be arranged after the merger of the lines of the bypass 1 7 and the exhaust gas heat exchanger output to delektieren a mixing temperature of the exhaust gas to the exhaust gas heat exchanger 16 and bypass 17. Optionally, it may also be sufficient if the temperature of the exhaust gas at the outlet of the exhaust gas heat exchanger 16 itself is measured. It is advantageous if the amount of exhaust gas flowing through the bypass can be determined, the typical temperature of which can also be estimated. This can an icing temperature can also be determined. Optionally, it may also be sufficient if the temperature at the outlet of the bypass line is detected.

The exhaust gas heat exchanger 16 is advantageously designed in two stages and has a first cooling stage, which is also called high-temperature cooling stage 20. Furthermore, the exhaust gas heat exchanger 16 has a second cooling stage, which is also called low-temperature cooling stage 21. In this case, the high-temperature cooling stage 20 of the low-temperature cooling stage 21 is connected upstream in the exhaust gas flow. Advantageously, the high-temperature stage 20 and the low-temperature stage 21 of the exhaust gas heat exchanger 16 are integrally formed, so that the exhaust gas only flows through an exhaust gas heat exchanger as such with two cooling stages 20,21, which are designed as a structural unit. Alternatively, the exhaust gas heat exchanger 16 with the two cooling stages may also have a modular design, and consist of two individual heat exchangers 20,21, which are fluidly connected to each other, for example via a pipe connection, so that the exhaust gas first through the first heat exchanger 20 with the first cooling stage and then flows out of this heat exchanger 20 in a second heat exchanger 21 of the second cooling stage. As the exhaust gas is thus first cooled to a temperature in the first cooling stage of the heat exchanger, the cooling preferably corresponds to the cooling with a normal Kühifluid the internal combustion engine, so that the temperature corresponds approximately to the cooling fluid temperature of the cooling circuit. This exhaust gas, which has already been cooled in advance, then flows through the second cooling stage 21 of the exhaust gas heat exchanger 16, which is preferably cooled with a second cooling fluid, which preferably has a lower temperature than the first cooling fluid. The second cooling fluid is thus a so-called low-temperature cooling fluid. This ensures that the exhaust gas is cooled in the second cooling stage 21 once again from the initial temperature of the first heat exchanger 20 to a final temperature T _mü , the clear is reduced with respect to the outlet temperature T _aU s-stufei the first heat exchanger.

The first cooling stage 20 of the exhaust gas heat exchanger 16 has a bypass 19, which is controllable via a valve, which is not shown in Figure 1. In this case, the amount of exhaust gas flowing through the bypass 19 or flowing through the first cooling stage 20 can be adjusted by means of this valve. In this case, this valve, not shown, advantageously arranged in the input diffuser of the heat exchanger 16 and the first cooling stage 20 or upstream of this. The bypass 19 terminates correspondingly at the output of the heat transfer region of the first cooling stage 20 and is introduced between the end region of the first heat transfer region of the first cooling stage 20 and the input region of the second heat transfer region of the second cooling stage 21 again. It is thus achieved that the exhaust gas bypassing the first heat transfer region of the first cooling stage 20 can nevertheless be cooled by the second cooling stage 21.

The intake manifold 3 fresh air for the burns in the cylinders of the internal combustion engine 1 is supplied. In this case, this fresh air is supplied as so-called charge air under charged pressure. The supply takes place through the input line 22, wherein the air is charged from the line 22 coming from the turbine 23 of the turbocharger 7 and placed under a first pressure, so that in the output line 24 of the first turbocharger 7, the charge air to a first middle Charge air pressure p _mi tt _e i brought. Subsequently, the charge air flows through a first intercooler 25, which is also referred to as a low-pressure charge air cooler. On the output side of the intercooler 25, the charge air flows through the turbine 26 of the second turbocharger 6 and is charged there to a second higher pressure level Phoch. On the output side of the turbocharger 6, the charge air is then fed via a valve 28 to a second charge air cooler 29, the high-pressure charge air cooler, in the line 27. The high pressure charge air cooler 29 cools the charge air in turn, so that the output side of the charge air cooler 29 is a charge air at low temperature.

Parallel to the intercooler 29, a bypass 30 is arranged, which can be flowed through by the charge air in the high pressure region. The dependence of the amount of charge air flowing through the heat exchanger 29 or flowing through the bypass 30 is controlled by the valve 28. In this case, the valve 28 can control both the division and the amount of the charge air cooler 29 flowing through charge air. On the output side of the bypass 30 and the heat exchanger 29, it then flows charge air into the intake manifold 3, wherein previously an admixture of the recirculated exhaust gas to the charge air takes place. This occurs at the point 63, at which the exhaust pipe is connected to the charge air line. At the output of the heat exchanger 29, a temperature sensor may be provided which can detect the temperature of the charge air at the outlet of the charge air cooler 29.

The bypass 30 is designed such that it comprises a heater 32, which can heat the charge air flowing through the bypass 30 by heating. In this case, the heater 32 may be electronically controlled and electrically operated, for example.

By the additional heating in the region of the bypass 30 of the charge air cooler 29, an admixing of heated charge air to the cooled charge air can be carried out in such a way that the final temperature of the charge air can be selectively adjusted before it is fed to the intake manifold 3.

Furthermore, it can be seen that the internal combustion engine 1 comprises a first cooling circuit 33 and a second cooling circuit 34. The first cooling circuit 33 represents the cooling circuit for the internal combustion engine as such, which may also be referred to as a high-temperature cooling circuit. The cooling circuit 34 is a reduced in temperature compared to the temperature of the first cooling circuit 33 cooling circuit, which can also be referred to as a low-temperature circuit. The cooling circuit 33 has a pump 35 which introduces coolant into the engine housing of the internal combustion engine. There, the coolant flows through the internal combustion engine and leaves the output side of the internal combustion engine with an increased coolant temperature. The coolant flows out of the internal combustion engine 1 through the line 36 and is supplied via the thermostatic valve 37 either to a bypass 38 and / or to a coolant cooler 39, the thermostat 37 controlling the quantity of coolant either through the bypass 38 or not depending on the coolant temperature and / or flows through the heat exchanger 39. On the output side of the heat exchanger 39, the coolant flows back again via the pump 35 to the internal combustion engine 1. Furthermore, a fan 40 is shown, which can set, for example electronically controllable, the cooling air for the radiator 39.

The cooling circuit 33 also feeds the coolant for flowing through the first exhaust gas heat exchanger 16 or the first cooling stage 20 of the exhaust gas heat exchanger 16 via a secondary passage 41, so that the coolant can flow into the heat exchanger 16 or the first cooling stage 20 in the region of a connection, the heat exchanger 16 and the first cooling stage 20 can flow through and can be returned to the cooling circuit 33 via the line 42 after an outflow from the heat exchanger 16 and from the first cooling stage 20 again.

Thus, the first cooling stage 20 of the exhaust gas heat exchanger 16 is cooled by a coolant mass flow of the first coolant circuit 33. The second coolant circuit 34, the low-temperature circuit, has a coolant cooler 43, which is preferably the coolant cooler 39 of the High-temperature cooling circuit 33 is connected upstream in the air flow of the motor vehicle, so that the cooling air first flows through the low-temperature coolant cooler 43 before the already heated-up cooling air 44 flows through the high-temperature coolant radiator 39.

With the pump 45, the low-temperature coolant is passed via line 46 and via line 47 to the low-pressure charge air cooler 25, where the low-temperature coolant flows through the intercooler 25, wherein the flow through the valve 48 at the outlet of the intercooler 25 is controlled. Then, the coolant flows through the line 49 back to the radiator 43. Starting from the line 46 also flows coolant through the line 50 to the second charge air cooler 29, flows through this, again a valve 51 control the mass flow of the low-temperature coolant through the charge air cooler 29 can. After the low-temperature coolant exits, it flows through the outlet line 52 back to the low-temperature coolant cooler 43.

To protect the components of the internal combustion engine 1, the relevant components are immunized by foreseeable measures such that they can permanently withstand the generated condensate.

In particular:

• the exhaust valve 15, also exhaust gas recirculation valve

The exhaust gas cooler 16, the first and / or the second cooling stage 20, 21 of the charge air cooler 29 in the high-pressure region

• the intercooler 25 in the low pressure range

• The intake port also referred to as the intake module 3

• the intake valves of the internal combustion engine

• the valve guide of the intake valves

· Valve seating rings of inlet valves

• the head gasket of the cylinder head • the cylinder surfaces of the cylinders of the internal combustion engine

• the pistons

• the piston rings

• the annular grooves of the pistons

· The exhaust flap

• the turbocharger 6,7

• exhaust duct 5,9,13

• the exhaust gas filter 12. The treatment for the immunization of the relevant hazardous components can be done in particular by the choice of material, the type of coating, a chrome plating, a chrome coating, a PVD coating. In this case, for example, a plasma sprayed layer can be applied, such as preferably on the cylinder surfaces or on other parts.

As the material for components of the internal combustion engine, for example, an iron-based material having a high chromium content can be used, with a NiCR based material, for example, CraCa / NiCr. In this case, an iron-based material with NiCr, WC, Co, or titanium carbide can be used as wear protection.

For example, such materials may be used in place of others to increase corrosion resistance or wear resistance. Furthermore, a material may be used which has NiCrBSi, for example in combination with iron or carbides, such as WC or Cr ₃ C ₂ .

Furthermore, an iron-based material with a high chromium content as well as with ceramic oxides, such as titanium oxide (Ti0 ₂ ) may be used. For piston rings, an iron-based material with a high chromium content, as described above, may also be used, which, for example, further contains ceramic materials. These may be, for example, titanium oxide or chromium oxide (Ti0 ₂ or Cr ₂ 0 ₃ ).

Furthermore, a coating may be done with chromium or with a material that is a nickel-based coating. This can preferably also be used with phosphorus. In addition, DLC coatings are possible.

The coating according to the invention can be:

A coating by PVD (Physical Vapor Deposition) physical vapor deposition. In the process, a high-quality tribological and functional layer is deposited in the thickness range from a few nanometers to a few tens of micrometers. Nearly all metals can be deposited by means of PVD processes. These layers can also be produced as solderable layers and they can be suitable for tribological applications.

A coating by means of PACVD (plasma-assisted chemical vapor deposition): The deposition of layers from the gas phase is supported by a plasma.

The layer thickness by PVD and PACVD (PECVD) is between 1 pm - 50 m. The layer thickness in a galvanic generation is several

100um,

Spray coatings or thermal spray coatings have a layer thickness of several 100 pm. The temperature resistance of the layers is as follows: In the case of layers by means of PACVD, a temperature resistance of up to approximately 400 ° C. is present.

For PVD coatings, a temperature resistance of up to more than 1000 ° C is present.

In galvanic layers, a temperature resistance is up to about 800 ° C and more.

The material basis is as follows:

At PVD, the material is metal.

In PACVD, the material is mostly gas.

In the case of sprayed coatings and thermal sprayed coatings, the material is metal + ceramic + oxides.

In galvanic spray coatings, the material is usually a metal or metals.

Claims

claims

Internal combustion engine with an arrangement for the return of exhaust gas and supply of cooled charge air to the internal combustion engine, wherein the internal combustion engine comprises an exhaust gas charging and an exhaust gas cooling system, with

an exhaust gas cooling system having a one- or two-stage exhaust gas cooler with a first cooling stage and optionally with a second cooling stage, with at least one bypass for bypassing the first and / or the second cooling stage of the exhaust gas cooler and with at least one exhaust gas control valve,

at least a first intercooler and a bypass for bypassing the first intercooler and with a charge air control valve,

characterized in that components of the arrangement and / or the internal combustion engine, which come into contact with an acid condensate preferably produced in the exhaust gas cooler and / or in the intercooler, are designed or treated such that they withstand the acidic condensate.

Internal combustion engine according to claim 1, characterized in that these are components, such as the exhaust valve (1 5) or the exhaust gas recirculation valve, the exhaust gas cooler (16), the first and / or the second cooling stage (20,21) of the exhaust gas cooler, the intercooler ( 29) in the high pressure region, the charge air cooler (25) in the low pressure region, the intake passage or the intake module (3), the intake valve or the intake valves of the internal combustion engine, the valve guide of the intake valve, the valve seat ring of the intake valve, the head gasket of the cylinder head, the cylinder surface of the cylinder of the internal combustion engine, the piston or pistons, the piston rings, the annular groove of the pistons, the exhaust flap, the turbocharger or the (6 7), the exhaust passage (5,9,13), the exhaust filter (12).

3. Internal combustion engine according to any one of the preceding claims, characterized in that the training or treatment for the immunization of the components in particular by the type of choice of material, the type of coating, the type of chrome plating, the type of chromium plating, the type of PVD coating in which a plasma spray can be applied.