DE102007038242A1 - Method for recirculating exhaust gas from outlet line into inlet line of internal combustion engine, involves arranging compressor in inlet line and exhaust gas turbocharger in outlet line - Google Patents

Abstract

The method involves arranging a compressor (4) in an inlet line (2) and an exhaust gas turbocharger (6) in an outlet line (3). An exhaust gas recirculation line (7) is provided between the inlet line and outlet line and downstream of a turbine (5) and upstream of the compressor. An adjustment of a portion of exhaust gas is carried out, which is removed of the outlet line and upstream of the compressor of the inlet line are supplied again, depending on the temperature in the inlet line. An independent claim is included for a device for recirculating exhaust gas from an outlet line into an inlet line of an internal combustion engine.

Description

The The present invention relates to a method and an apparatus for recirculation of exhaust gas according to the Features of the independent claims.

It is well known that a repatriation of Exhaust of an internal combustion engine from the exhaust to the intake pipe causes a lower nitrogen oxide formation during combustion.

to Recirculation of exhaust gas have become common in internal combustion engines with exhaust gas turbocharger several variants developed. Accordingly it is possible the exhaust gas upstream of the turbine remove the exhaust gas turbocharger the exhaust pipe and downstream the compressor of the exhaust gas turbocharger supply the intake pipe again. A disadvantage of this so-called high-pressure exhaust gas recirculation is it that due to short line lengths between the Introduction of exhaust gas into the intake pipe and the combustion chambers a good mixing of exhaust gas and fresh air is not ensured is. Besides, it becomes relative returned hot exhaust gas, resulting in effective Reduction of nitrogen oxide formation in turn an additional Radiator in the exhaust gas recirculation line to Lowering the temperature of the exhaust gas requires. About that In addition, there is not a sufficient pressure gradient in all operating points between the outlet and inlet duct in front, allowing a return limited by exhaust gas to operating ranges of the internal combustion engine is, in which there is a higher pressure in the outlet, as in the inlet pipe.

to Avoiding these disadvantages, it is previously known, downstream exhaust gas remove the turbine of the exhaust gas turbocharger the exhaust line and upstream of the compressor of the exhaust gas turbocharger Supply inlet line again. In particular, it is at this so-called low-pressure exhaust gas recirculation advantageous that the exhaust gas comparatively long line lengths flows through the compressor, so that ensures a good mixing of exhaust gas and fresh air is. In addition, colder exhaust gas is returned and a further cooling of the mixture of exhaust gas and fresh air can be done advantageously in a cooler, the stream downstream of the compressor is arranged in the inlet line. Farther exists in terms of operating areas in which a return of exhaust is possible, no limitation, there a pressure differential between the outlet and inlet ducts for the return of exhaust artificially over an exhaust flap can be generated.

About that In addition, combinations of high pressure and low pressure exhaust gas recirculation are known, which complement each other favorably.

in principle However, in the aforementioned variants of the exhaust gas recirculation by the cooling of the recirculated Exhaust gas condensation occurs in the water during combustion is formed and that in the recirculated exhaust gas is included. As a result, it can not be ruled out that aggressive liquids are formed, leading to corrosion effects lead in the intake of the internal combustion engine can. The condensation of the water takes place in the sun especially low-pressure exhaust gas recirculation inside and in the area of the intercooler, downstream of the compressor is arranged in the inlet line, as there is a relatively high pressure level prevails and the actually desired cooling of the mixture made of exhaust gas and fresh air.

To avoid these adverse effects, according to the document US 6725847 B2 in a high-pressure exhaust gas recirculation proposed to first determine the partial pressure of the water in the mixture of fresh air sucked in and recirculated exhaust gas in the intake system. Furthermore, it is proposed to close by means of the vapor pressure line of the water of the respective partial pressure on the current condensation temperature. If the temperature in the intake system is below the current condensation temperature of the water, the valve in the exhaust gas recirculation line closes and no exhaust gas is recirculated.

It However, it is disadvantageous that a return of Exhaust not under all operating conditions of the internal combustion engine can be done and a continuous reduction of nitric oxide formation is not ensured during combustion.

Furthermore, according to the document DE 102 58 402 A1 encouraged to determine the current ambient and operating conditions of the internal combustion engine and to determine a dew point to reduce condensation effects in the intake system of an internal combustion engine with a high-pressure exhaust gas recirculation. By comparing a measured temperature in the intake with the determined dew point can be determined whether condensation effects can occur or not. To avoid condensation effects, it is proposed to pass a portion of the exhaust gas to be recirculated past an exhaust gas cooler and / or a portion of the fresh air past a charge air cooler.

It is disadvantageous that an additional cooler in the exhaust gas recirculation line must be provided for the effective reduction of nitrogen oxide formation during combustion. Furthermore, a good mixing of exhaust gas and fresh air is not ensured, since only a so-called High-pressure exhaust gas recirculation is used. In addition, additional bypass lines and a plurality of valves are required to allow bypassing the recirculating exhaust gas and / or the fresh air to the respective existing coolers in the exhaust gas recirculation and inlet line. Furthermore, from a control point of view, a system consisting of several line volumes, which are filled with a compressible medium, as well as a not sure constant constant power of several coolers, demanding. Consequently, a precise adjustment of the temperature in the intake system and a safe avoidance of condensation effects is questionable or can only be achieved with considerable development effort.

task

It Object of the present invention, a possibility to create, in a simple way, an internal combustion engine at all operating points and with reliable prevention of condensation effects as big as possible and good with fresh air recycled proportion of exhaust gas again.

solution

These The object is achieved according to the invention that the adjustment of the proportion of exhaust gas, which of the outlet taken and upstream of a compressor of the inlet pipe again is supplied, depending on the temperature takes place in the inlet line. In particular, the adjustment is done the proportion of exhaust gas taken from the exhaust duct and upstream the compressor is returned to the inlet line, in Dependence of the temperature in the inlet line downstream of the compressor. Preferably, the adjustment of the proportion takes place Exhaust gas taken from the outlet and upstream the compressor is returned to the inlet line, depending on the temperature in the inlet line downstream of the compressor inside or in the area of a charge air cooler.

Lies the temperature in the inlet pipe in one with respect to a Condensation critical area, is advantageous according to the invention the proportion of exhaust gas taken from the outlet and upstream the compressor is returned to the inlet line, so far reduced that no condensation in the inlet line occurs. In this way it is advantageous according to the invention possible, always a maximum possible share supply of exhaust gas of the internal combustion engine again, which taken from the outlet and upstream of a compressor the inlet line is fed back without a Condensation in the inlet line occurs. Accordingly stands the Internal combustion engine always a maximum possible proportion to exhaust available, which taken from the outlet and upstream of a compressor of the inlet conduit is fed again and mixes well with the fresh air is because the exhaust gas comparatively long line lengths including the compressor flows through.

Around the total amount of exhaust gas, which of the internal combustion engine recycled, to maintain quantitatively, it is provided in an advantageous embodiment of the present invention, both exhaust downstream of the turbine of the exhaust gas turbocharger remove the outlet and upstream of the compressor the exhaust gas turbocharger the intake line again, as also exhaust gas upstream of the turbine of the exhaust gas turbocharger remove the outlet and downstream of the compressor supply the exhaust gas turbocharger the intake pipe again.

there are two variants of the introduction according to the invention of the exhaust gas into the inlet duct possible, which upstream taken from the turbine of the exhaust gas turbocharger exhaust pipe and downstream fed back to the compressor of the exhaust gas turbocharger the inlet pipe becomes.

In the first variant, the exhaust gas downstream of the compressor of the exhaust gas turbocharger and upstream of the charge air cooler is supplied to the inlet line. Advantageously in accordance with the invention, in this way both the temperature of the mixture of air and recirculated exhaust gas is raised prior to entry into the charge air cooler and effective prevention of formation of condensate within or in the area of the charge air cooler, as well as the total amount of exhaust gas which is returned to the internal combustion engine is maintained quantitatively. In particular, the proportion of exhaust gas taken from the exhaust gas turbine upstream of the turbocharger turbine and recirculated to the intake manifold downstream of the compressor can be varied rapidly and directly, since there are short pipe lengths and the relatively hot exhaust gas portion is present , but possibly even too cool a mixture of exhaust gas and fresh air, which has already passed the compressor, is mixed, so that there are favorable conditions for controlling the temperature in the inlet line. Advantageously according to the invention, a maximum possible proportion of exhaust gas can be recirculated, which is taken downstream of the turbine of the exhaust gas turbocharger exhaust line and upstream of the compressor of the exhaust gas turbocharger inlet pipe is fed again and is well mixed with the fresh air, wherein further an additional proportion of exhaust gas with high temperature added to the already existing mixture of fresh air and exhaust gas is added to stabilize the temperature in or around the intercooler so that no condensation effects occur.

A Limit of this first variant of the method can be seen therein that to stabilize the temperature so much exhaust upstream taken from the turbine of the exhaust gas turbocharger exhaust pipe and downstream of the compressor of the exhaust gas turbocharger of the inlet pipe is fed back that the disadvantages of a less good mixing of the recirculated exhaust gas outweigh the fresh air to be supplied. Furthermore is to be assumed that by the compared to be supplied Fresh air or ambient air high proportion of water in the recirculating Exhaust gas, the temperature below which condensation effects occur in the inlet line, disproportionately with the Proportion of recirculating exhaust gas increases with the Result that in this first process variant relatively early a reduction in the total proportion of recirculating Exhaust gas must be made. In other words, by means of this first Process variant up to a certain limit temperature in or in the area of the intercooler a cooler overall proportion supplied to exhaust gas of the internal combustion engine again but the total share is reduced comparatively early must become.

at the second process variant, the proportion of exhaust gas, which the exhaust pipe upstream of the turbine of an exhaust gas turbocharger was taken, downstream of the compressor of the exhaust gas turbocharger and downstream of the charge air cooler of the intake passage fed. According to the invention is for the case that the temperature in the inlet pipe in a respect a condensate formation critical range, the proportion of exhaust gas, which of the outlet duct is preferably downstream of the turbine taken from an exhaust gas turbocharger and upstream of the Compressor is returned to the inlet pipe, as far as reduces the formation of condensation in the inlet pipe. To the entire proportion of exhaust gas, which of the internal combustion engine recycled, to maintain quantitatively, is now in addition to the already largely homogenized and cooled mixture of fresh air and exhaust gas containing the Compressor and intercooler in the inlet line has already passed, a proportion of exhaust gas fed to the inlet line, which of the exhaust duct upstream of the turbine of the Exhaust gas turbocharger was removed. In other words, at the second variant, the current temperature in the intercooler taken as given and there is a cessation of the share on exhaust gas, which taken from the outlet and upstream a compressor is returned to the inlet line, depending on the temperature in the inlet pipe, wherein when it falls below the temperature, at the condensation effects can occur in the inlet pipe, a reduction the proportion of exhaust gas takes place, which taken from the outlet and upstream of a compressor of the inlet conduit is fed back, being downstream of the Intercooler by the supply of further Exhaust from the exhaust pipe, upstream of the turbine is taken, a required total amount of exhaust gas in the inlet pipe is formed, which fed to the internal combustion engine shall be. In this way it is advantageous according to the invention possible, regardless of a specific temperature limit within or in the area of the intercooler always a maximum Supply total amount of exhaust gas of the internal combustion engine again.

In an embodiment of the present invention is provided, in a first step, the temperature in the inlet line to determine. In a further step, it is provided by means of Vapor pressure line of the water and the temperature in the inlet line to close the maximum partial pressure of the water, in which just no condensation in the inlet line occurs. In yet another step, it is provided the maximum Partial pressure of the water, at which just no condensation occurs in the intake passage, the combustion air ratio, the Inlet line pressure, ambient temperature, relative Humidity and the ambient pressure of a calculation rule and in yet another step, by means of the calculation rule to determine a maximum amount of exhaust gas which of the exhaust duct taken and upstream of a compressor inlet line is fed again, wherein the proportion of exhaust gas is preferred the exhaust duct downstream of the turbine of an exhaust gas turbocharger is removed.

The calculation rule preferably represents an inverted condensation model, which is based on the maximum partial pressure of the water, in which just no condensation formation in the inlet line occurs, the temperature in the inlet line within or in the region of the charge air cooler, the combustion air ratio, the pressure in the inlet line, the ambient temperature, the relative humidity, the ambient pressure, the chemical properties of the fuel and information on the total amount of exhaust gas, which is to be returned to the internal combustion engine, allows a determination of the proportion of exhaust gas taken from the outlet and upstream of a compressor inlet line is fed again. In this way, according to the invention it is possible to determine how large the proportion of exhaust gas, which is taken from the outlet line and fed back to the inlet line upstream of a compressor, at the total th proportion of exhaust gas may be, which is supplied to the internal combustion engine again without condensation effects occur in the inlet pipe.

Of the entire share of exhaust gas, which is the internal combustion engine again is supplied, is made up of the proportion of exhaust gas, the downstream of the turbine of the exhaust gas turbocharger exhaust pipe taken and upstream of the compressor of the exhaust gas turbocharger the inlet line is returned and the proportion on exhaust gas upstream of the turbine of the exhaust gas turbocharger taken from the outlet and downstream of the compressor the exhaust gas turbocharger the inlet line fed back will, together.

In a particularly simple embodiment are only one or more tables providing an association between the Temperature in the inlet pipe or in the area of the intercooler, below which occur condensation effects and the Proportion of exhaust gas taken from the outlet and upstream a compressor is fed back to the inlet line. It can continue assignments for various Ambient and operating conditions of the internal combustion engine be provided. The tables or maps are under development the individual internal combustion engine individually.

Furthermore For example, the present invention includes a device that is one of includes a computer readable storage medium in which a calculation rule is stored to the proportion of exhaust gas, which of the outlet taken and upstream of a compressor inlet line is fed again, depending on the temperature to be able to adjust in the inlet line.

embodiment

Further advantageous embodiments are the description of the below illustrated embodiment of the invention.

in this connection demonstrate:

1 : a schematic representation of an internal combustion engine with a combination of high-pressure and low-pressure exhaust gas recirculation,

2 : Another schematic representation of an internal combustion engine with a combination of high pressure and low pressure exhaust gas recirculation.

The present invention will be described using the example of an internal combustion engine 1 explains which preferred in 1 having features shown. The internal combustion engine 1 includes an inlet conduit 2 and an outlet conduit 3 , In the inlet pipe 2 is the compressor 4 and in the outlet line 3 the turbine 5 an exhaust gas turbocharger 6 arranged. Downstream of the turbine 5 and upstream of the compressor 4 is between the inlet pipe 2 and the outlet pipe 3 a first exhaust gas recirculation line 7 intended. Furthermore, upstream of the turbine 5 and downstream of the compressor 4 between the inlet pipe 2 and the outlet pipe 3 a second exhaust gas recirculation line 8th arranged. In addition, downstream of the compressor 4 in the inlet pipe 2 a charge air cooler 9 arranged. In addition, in the first exhaust gas recirculation line 7 a valve 10 and in the second exhaust gas recirculation line 8th a valve 11 arranged. Furthermore, in the inlet line 2 a means for detecting the temperature 12 arranged. Preferably, the means for detecting the temperature 12 around a temperature sensor inside or in the area of the intercooler 9 in the inlet pipe 2 is arranged. Furthermore, for the purpose of influencing the pressure gradient between the inlet line 2 and the outlet pipe 3 in the inlet pipe 2 a throttle 13 arranged. In addition, in the outlet pipe 3 a stowage flap 14 arranged to the pressure drop between the inlet pipe 2 and the outlet pipe 3 to influence. The introduction of the exhaust gas from the outlet pipe 3 via the second exhaust gas recirculation line 8th in the inlet pipe 2 takes place according to 1 downstream of the compressor 4 and upstream of the intercooler 9 , The valves 10 and 11 and the means for detecting the temperature 12 are not shown lines with a device, also not shown for controlling and regulating the internal combustion engine 1 coupled comprising a computer-readable storage medium.

According to a in 2 shown alternative variant, the introduction of the exhaust gas from the outlet line 3 in the inlet pipe 2 via the second exhaust gas recirculation line 8th downstream of the compressor 4 and downstream of the intercooler 9 ,

According to the invention, it is provided in the operation of an internal combustion engine 1 according to the 1 and 2 the largest possible amount of exhaust gas from the outlet pipe 3 in the inlet pipe 2 over the first exhaust gas recirculation line 7 taking into account the temperature in the inlet pipe 2 recirculate.

According to the invention, in a first method step on the basis of the means for detecting the temperature 12 a temperature value determined and the device, not shown, for controlling and regulating the internal combustion engine 1 fed.

In a second method step takes place on the basis of a first calculation rule, which in the computer-readable storage medium in the device for controlling and regulating the internal combustion engine, not shown 1 is stored by means of the vapor pressure line of the water and the temperature value in the inlet line 2 a conclusion on the maximum partial pressure of the water, with just no condensation in the inlet line 2 occurs.

In a third method step, the maximum partial pressure of the water determined in the second method step is just barely condensed in the inlet line 2 occurs, as well as a value of the combustion air ratio, which is stored, for example, as a desired value as a function of the operating parameters load and speed in the form of a map in the computer-readable storage medium or metrologically determined, fed to a second calculation rule.

Furthermore, the second calculation rule becomes the pressure in the intake pipe 2 for example, by means of a pressure sensor, not shown, downstream of the compressor 4 in the inlet pipe 2 is determined, and supplied by means of sensors also not shown certain ambient temperature, the relative humidity of the ambient air and the ambient air pressure. The determination of the relative humidity can be done by means of sensors, wherein alternatively the humidity can be specified as a constant value, which is preferably individually bedatet for different countries.

Further, a supply of the chemical properties of the fuel to the second calculation rule as well as a supply of information about the total proportion of exhaust gas, which is the internal combustion engine 1 should be returned.

In a fourth method step, a maximum proportion of exhaust gas is determined by means of the second calculation rule, which of the outlet line 3 taken and upstream of a compressor 4 the inlet pipe 2 is supplied again, wherein the proportion of exhaust gas preferably the outlet line 3 downstream of the turbine 5 the exhaust gas turbocharger 6 is removed.

It is now possible according to the invention, in a fifth method step based on the result, obtained in the fourth process step, two different ones Ways to respond.

There is a possibility of the proportion of exhaust gas, which upstream of the turbine 5 the outlet pipe 3 taken out and downstream of the compressor 4 the inlet pipe 2 is fed back to leave uninfluenced and, if necessary, only the proportion of exhaust gas, which downstream of the turbine 5 the outlet pipe 3 taken and upstream of the compressor 4 the inlet pipe 2 is returned, to vary.

Furthermore, there is the possibility of the proportion of exhaust gas, which downstream of the turbine 5 the outlet pipe 3 taken and upstream of the compressor 4 the inlet pipe 2 is fed again and which to exceed the maximum partial pressure of the water or condensate formation in the inlet line 2 would lead to redirect to the proportion of exhaust gas, which upstream of the Turbi ne 5 the outlet pipe 3 taken out and downstream of the compressor 4 the inlet pipe 2 is fed again.

The said process steps are cyclically processed again and again, so that always the setting of the maximum proportion of exhaust gas takes place, which is the outlet line 3 taken and upstream of a compressor 4 the inlet pipe 2 is fed again.

1

Internal combustion engine

2

inlet line

3

outlet pipe

4

compressor

5

turbine

6

turbocharger

7

first Exhaust gas recirculation line

8th

second Exhaust gas recirculation line

9

Intercooler

10

Valve

11

Valve

12

medium for detecting the temperature

13

throttle

14

jam door

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6725847 B2 [0007]
• - DE 10258402 A1 [0009]

Claims (17)

Method for recirculating exhaust gas from the outlet line ( 3 ) into the inlet line ( 2 ) an internal combustion engine ( 1 ), wherein in the inlet line ( 2 ) of the compressor ( 4 ) and in the outlet line ( 3 ) the turbine ( 5 ) of an exhaust gas turbocharger ( 6 ) and downstream of the turbine ( 5 ) and upstream of the compressor ( 4 ) between the inlet line ( 2 ) and the outlet line ( 3 ) an exhaust gas recirculation line ( 7 ), characterized in that the adjustment of the proportion of exhaust gas, which of the outlet ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is supplied again, depending on the temperature in the inlet line ( 2 ) he follows. Method according to claim 1, characterized in that the adjustment of the proportion of exhaust gas, which of the outlet pipe ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is supplied again, depending on the temperature in the inlet line ( 2 ) downstream of the compressor ( 4 ) he follows. Method according to claim 1, characterized in that the adjustment of the proportion of exhaust gas, which of the outlet pipe ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is supplied again, depending on the temperature in the inlet line ( 2 ) downstream of the compressor ( 4 ) within or in the area of an intercooler ( 9 ), which is also downstream of the compressor ( 4 ) in the inlet line ( 2 ) is arranged. Method according to one of the preceding claims, characterized in that in the inlet line ( 2 ) means for detecting the temperature ( 12 ) is arranged. Method according to claim 4, characterized in that the means for detecting the temperature ( 12 ) is a temperature sensor inside or in the area of the intercooler ( 9 ) in the inlet line ( 2 ) is arranged. Method according to one of the preceding claims, characterized in that when the temperature in the inlet line ( 2 ) is in a critical with respect to a condensate formation range, the proportion of exhaust gas, which of the outlet ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is fed back, as far as reduced, that no condensation in the inlet line ( 2 ) occurs. Method according to one of the preceding claims, characterized in that both exhaust gas downstream of the turbine ( 5 ) of the exhaust gas turbocharger ( 6 ) of the outlet line ( 3 ) and upstream of the compressor ( 4 ) of the exhaust gas turbocharger ( 6 ) of the inlet pipe 2 is recirculated, as well as exhaust gas upstream of the turbine ( 5 ) of the exhaust gas turbocharger ( 6 ) of the outlet line ( 3 ) and via a further exhaust gas recirculation line ( 8th ) downstream of the compressor ( 4 ) of the exhaust gas turbocharger ( 6 ) of the inlet pipe ( 2 ) is returned to a total amount of exhaust gas, which of the internal combustion engine ( 1 ) is to be supplied. Method according to claim 7, characterized in that the introduction of the exhaust gas from the outlet ( 3 ) into the inlet line ( 2 ) via the further exhaust gas recirculation line ( 8th ) downstream of the compressor ( 4 ) and upstream of the intercooler ( 9 ) or downstream of the compressor ( 4 ) and downstream of the intercooler ( 9 ) he follows. Method according to one of the preceding claims, characterized in that in a first step, the temperature in the inlet line ( 2 ) is determined in a further step by means of the vapor pressure line of the water and the temperature in the inlet line ( 2 ) is closed to the maximum partial pressure of the water, at which just no condensation in the inlet line ( 2 ) occurs, in a further step, the maximum partial pressure of the water, in which just no condensation in the inlet line ( 2 ) occurs, the combustion air ratio, the pressure in the inlet line ( 2 ) and the ambient temperature, the relative humidity, the ambient pressure, the chemical properties of the fuel and information on the total amount of exhaust gas, which of the internal combustion engine ( 1 ) is to be supplied again, is supplied to a calculation rule and in a further step by means of the calculation rule a maximum proportion of exhaust gas is determined which of the outlet line ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is returned. A method according to claim 9, characterized in that the calculation rule is an inverted condensation model, wherein based on the maximum partial pressure of the water, in which just no condensation in the inlet line ( 2 ), the temperature in the inlet line ( 2 ) within or in the area of the intercooler ( 9 ), the combustion air ratio, the pressure in the intake pipe ( 2 ), the ambient temperature of the relative humidity, the ambient pressure, the chemical properties of the fuel information on the total amount of exhaust gas, which of the internal combustion engine ( 1 ) is to be supplied again, a determination of the proportion of exhaust gas takes place, which of the outlet ( 3 ) and upstream of a Ver poet ( 4 ) of the inlet pipe ( 2 ) is returned. A method according to claim 9, characterized in that one or more tables are provided with an association between the temperature in the inlet line ( 2 ) within or in the area of the intercooler ( 9 ), below which occur condensation effects and the proportion of exhaust gas, which of the outlet ( 3 ) and upstream of a compressor ( 4 ) of the inlet pipe ( 2 ) is returned. Method according to one of the preceding claims, characterized in that in a - first method step based on the means for detecting the temperature ( 12 ) determines a temperature value and a device for controlling and regulating the internal combustion engine ( 1 ) and in a - second method step based on a first calculation rule, which in a computer-readable storage medium in the device for controlling and regulating the internal combustion engine ( 1 ) is stored by means of the vapor pressure line of the water and the temperature value in the inlet line ( 2 ) a conclusion is drawn on the maximum partial pressure of the water, in which just no condensation in the inlet line ( 2 ) occurs and in a - third process step of the determined in the second step, the maximum partial pressure of the water, in which just no condensation formation in the inlet line ( 2 ), a value of the combustion air ratio, the pressure in the intake pipe ( 2 ), the relative humidity of the ambient air, the ambient air pressure and information on the total amount of exhaust gas, which of the internal combustion engine ( 1 ) is to be supplied again, are supplied to a second calculation rule and in a - fourth method step by means of the second calculation rule a maximum proportion of exhaust gas is determined, which of the outlet line ( 3 ) and upstream of a compressor ( 4 ) of the inlet pipe ( 2 ) and, in a - fifth method step, based on the result obtained in the fourth method step, either the proportion of exhaust gas which is upstream of the turbine ( 5 ) of the outlet line ( 3 ) and downstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is returned, is left unaffected and, if necessary, only the proportion of exhaust gas, which downstream of the turbine ( 5 ) of the outlet line ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is varied, or the proportion of exhaust gas, which downstream of the turbine ( 5 ) of the outlet line ( 3 ) and upstream of the compressor ( 4 ) of the inlet pipe ( 2 ) and which leads to an exceeding of the maximum partial pressure of the water or to the formation of condensation in the inlet line ( 2 ) is diverted to the portion of exhaust gas which upstream of the turbine ( 5 ) of the outlet line ( 3 ) and downstream of the compressor ( 4 ) of the inlet pipe ( 2 ) is returned. Method according to claim 12, characterized in that the five method steps are cyclically executed again and again, so that always the adjustment of the maximum proportion of exhaust gas takes place, which of the outlet line ( 3 ) and upstream of a compressor ( 4 ) of the inlet pipe ( 2 ) is returned. Device for recirculating exhaust gas from the outlet line ( 3 ) into the inlet line ( 2 ) an internal combustion engine ( 1 ), wherein in the inlet line ( 2 ) of the compressor ( 4 ) and in the outlet line ( 3 ) the turbine ( 5 ) of an exhaust gas turbocharger ( 6 ) and downstream of the turbine ( 5 ) and upstream of the compressor ( 4 ) between the inlet line ( 2 ) and the outlet line ( 3 ) an exhaust gas recirculation line ( 7 ), characterized in that the device comprises a computer-readable storage medium in which a calculation rule is stored in order to determine the proportion of exhaust gas, which of the outlet line ( 3 ) and upstream of a compressor ( 4 ) of the inlet pipe ( 3 ) is supplied again, depending on the temperature in the inlet line ( 2 ) to adjust. Device according to claim 14, characterized in that upstream of the turbine ( 5 ) and downstream of the compressor ( 4 ) between the inlet line ( 2 ) and the outlet line ( 3 ) a further exhaust gas recirculation line ( 8th ) is arranged. Device according to claim 15, characterized in that the introduction of the exhaust gas from the outlet ( 3 ) into the inlet line ( 2 ) via the further exhaust gas recirculation line ( 8th ) downstream of the compressor ( 4 ) and upstream of the intercooler ( 9 ) or downstream of the compressor ( 4 ) and downstream of the intercooler ( 9 ) he follows. Device according to one of the claims 14 to 16, characterized in that the computer-readable storage medium is part of a device for controlling and regulating the internal combustion engine ( 1 ).