DE102009027639A1 - Exhaust gas system for e.g. six-cylinder V-engine of vehicle, has exhaust gas purification device arranged in exhaust gas stream, and compressor driven by drive mechanism to produce mechanical rotational energy - Google Patents

Abstract

The system (15) has a fresh air supply line (17) controlled by a butterfly valve (2). A turbocharger is provided with a compressor (1) and an exhaust gas-operated turbine (1.1). An exhaust gas purification device (12) is arranged in an exhaust gas stream. Another compressor (5) is arranged in an exhaust gas-return line (14) and is driven by a drive mechanism (5.1) e.g. electrical machine, for producing a mechanical rotational energy. A power output and/or speed of the mechanism are controlled depending on operating parameters of an internal-combustion engine (9). Independent claims are also included for the following: (1) a method for controlling an exhaust gas system (2) a control system for controlling exhaust gas streams of an exhaust gas system.

Description

The The invention relates to an exhaust system of an internal combustion engine with Exhaust gas recirculation, a method for controlling the Exhaust system, a control system for controlling the exhaust gas flows the exhaust system and an internal combustion engine with an exhaust system with exhaust gas recirculation with the in the preambles of the respective independent claims Features.

It is known that the regulations for the exhaust emissions of internal combustion engines with increasing number of vehicles are constantly tightening, such as EURO 6 standard in Europe or Animal 2 or I am 5 in USA. Some manufacturers prefer to use different firing strategies, such as HCCI (Homogeneous Charge Compression Ignition) or active aftertreatment devices such as NOx (Nitrogen Oxide) separators or SCR (Selective Catalytic Reduction) catalysts. However, these technologies require considerable material effort and development, increasing the complexity of the systems and imposing high consequential costs on the consumer such as higher fuel consumption and technology sustainability costs.

A the known strategies, the emissions of an internal combustion engine it is exhaust gas purification through exhaust gas recirculation that reduces emissions to improve. The exhaust gases still contain relatively much oxygen and are partially added to the fresh air supply, creating less Fresh air from the atmosphere must be removed. For this purpose, the exhaust gases are either directly after the exhaust manifold taken or only by a catalyst or particle filter cleaned emission control system cleaned and then partially over taken from a designated pipeline and the fresh air supply admixed to the intake manifold.

In US 7,165,540 B2 an exhaust gas recirculation system of an internal combustion engine is disclosed, in which two turbochargers, a high-pressure and a low-pressure turbocharger, are connected so that their drive stages or turbines are arranged one behind the other in the exhaust system and their compressor stages in the air supply tract or exhaust gas recirculation tract in a row. Part of the exhaust gas recirculation is also carried out between the two drive stages of the two turbochargers and is cooled via interposed radiators, switched with controlled valves and fed to a respective compressor of the two turbochargers. The aim of the complex interaction of the multiple exhaust gas recirculation is to match the pressure of the exhaust gases and the pressure of the charge air in a mixer to each other, so that mixing can be effective. The disadvantage here is that the power of the turbocharger are not linear to the exhaust gas power and therefore a pressure adjustment in all operating conditions of the internal combustion engine is difficult to control. This is particularly true for the second additional turbocharger because it must be designed for low pressure and therefore also brings larger dimensions and weight with it.

US 2002/0112478 A1 discloses a similar arrangement as in US 7,165,540 B2 , with a high-pressure and a low-pressure turbocharger whose charge air flow is controlled by means of controllable valves by a computer-aided control so that the compression of the charge air is optimized. The exhaust gas recirculation takes place unregulated and is taken only at the point in the exhaust system in front of the two turbochargers. Thus, an improved gas-cleaning effect by exhaust gas recirculation is not realized.

US 7,117,843 B2 discloses a diesel internal combustion engine having a low-pressure exhaust gas recirculation system, in which a turbocharger is present, in whose compressor via an exhaust gas cooler and a controlled exhaust valve part of the exhaust gases is recycled together with the fresh air. Although the system works with only one compressor and one turbine, the recirculated exhaust gases introduced into the fresh air section cause problems for the air filter system and clog it up relatively quickly. Furthermore, the air filter is exposed to high temperatures and must therefore withstand higher temperatures or the performance of the exhaust gas cooler are increased accordingly. The main disadvantage, however, is that the recirculation of the exhaust gases can not be guaranteed in all operating conditions of the internal combustion engine, since the pressure of the exhaust gases is subject to strong fluctuations.

US 6,050,095 discloses a turbocharger with integrated exhaust gas recirculation. In addition to the advantageous compactness of this solution, however, the named disadvantages adhere to it as well.

In US 2006/0124115 A1 discloses an exhaust system with an exhaust gas recirculation, which has two exhaust-gas turbochargers, each causing a partial compression. The mixing of the fresh air and the recirculated exhaust gases takes place before entering the first low-pressure compressor. The exhaust gas recirculation is connected downstream between the turbines of the two turbochargers and has a mini exhaust gas purification. This solution also has the disadvantages described above.

The invention has for its object to improve an exhaust system with exhaust gas recirculation so that the exhaust gases of the engine cleaned in all operating conditions of the engine even more effectively from pollutants or even less fresh air is needed and thus the emission values are lowered.

The The invention is based on a first device-technical aspect from an exhaust system of an internal combustion engine with exhaust gas recirculation, the with a regulated with a throttle Freshluftzuführstrang, at least one first exhaust gas recirculation train, at least a first turbocharger with a compressor and a exhaust gas driven turbine, and with at least one in the exhaust stream arranged exhaust gas purification device is equipped.

Thereby, that in at least one exhaust gas recirculation train at least one second compressor is arranged, the one of a a mechanical rotational energy generating drive mechanism driven is, the object of the invention is achieved.

The Power output and / or the speed of the drive mechanism of second compressor are preferably depending on Operating parameters of the internal combustion engine controllable and / or controlled.

Special Advantages are with an exhaust system according to the invention achieved when the drive mechanism is designed as an electric machine is, because an electric machine can be particularly flexible control.

According to one Another preferred embodiment of the present invention is the Exhaust gas recirculation train with second compressor downstream after the at least one emission control device to the exhaust system connected so that this exhaust gas feedback train represents a low pressure exhaust gas recirculation, and the first exhaust gas recirculation train downstream before the at least one exhaust gas purification device to the exhaust system is connected so that this exhaust gas feedback train represents a high pressure exhaust gas recirculation.

Further Advantages can be achieved according to the invention, when the exhaust gas flow through the exhaust gas recirculation train with second compressor via a controllable valve device can be switched on and off and / or throttled.

A even more preferred embodiment of the invention results when at least two exhaust gas recirculation lines over in each case a controllable valve device switched on and off and / or are throttled.

A more precise control of the composition of the fresh air and the recirculated Gases can be reached when in the Frischluftzuführstrang and in the exhaust gas recirculation line with second compressor in each case a pressure sensor is provided.

Especially advantageous developments of the invention Exhaust system arise when at least one valve device is controllable and / or controlled by a controller.

The Exhaust gas purification device preferably has at least one catalyst and / or a particulate filter. Furthermore, it can be made in several parts be connected by means of pipe connections.

Around the temperature of the recirculated exhaust gases to the to adapt thermal requirements of the internal combustion engine is in the Frischluftzuführstrang and / or in the exhaust gas recirculation train with a second compressor, preferably at least one cooler for cooling the fresh air and / or the recirculated Exhaust gases provided.

When Operating parameters of the internal combustion engine are preferably the exhaust gas recirculation rate and / or the relative oxygen concentration in the intake manifold (BGR) detected by means of a respective detection means. Such detection means may be, for example, an oxygen sensor or the operating parameters provided by a motor controller be.

To a procedural aspect of the present invention of a method for controlling the exhaust system with exhaust gas recirculation one of the previously described embodiment.

Thereby, that the power output of the drive mechanism and / or the speed of the second compressor in dependence on operating parameters the internal combustion engine are controlled, the object of the invention also solved procedurally.

Around To achieve lower NOx emissions, the exhaust gas recirculation rate be increased as possible. At the same time, to one To ensure optimum engine operation, is further than an important influencing factor for example the relative Oxygen concentration in the intake manifold (Burned Gas rate BGR, or also fuel gas rate) with the help of a superimposed Motor control regulated. This superimposed engine control can also be alternative with any conventional system be realized and in any case benefits from the fact that according to the invention by minimizing the pressure difference mixing the recirculated Exhaust gases with the fresh air is better optimized.

Here, for example, the relative acid Influent concentration in inlet manifold BGR = 1 - [O ₂ ] _INLET / [O2] _REF compared to the reference oxygen concentration in the air of [O ₂ ] _REF = 20.95% based on the detected oxygen concentration.

• – der stromabwärts vor einer Luft-Abgasmischvorrichtung erfaßte Druck in der Abgasrückführung einen vorgegebenen und/oder vorgebbaren Schwellenwert unterschreitet und/oder die Druckdifferenz zwischen dem Luftdruck im Frischluftzuführstrang und dem Abgasdruck in der Abgasrückführung einen vorgegebenen und/oder vorgebbaren Druckdifferenz-Schwellenwert unterschreitet
• – die Niederdruckabgasrückführung, der Abgas-Rückführstrang mit zweitem Verdichter, durch Öffnen der zugehörigen Ventilvorrichtung zugeschaltet, und
• – die Hochdruckabgasrückführung durch Schließen einer Hauptventilvorrichtung abgeschaltet oder mit geöffneter Hauptventilvorrichtung parallel zur Niederdruckabgasrückführung betrieben wird.

A particularly advantageous embodiment of the method can be realized in that if

• - The downstream of an air exhaust mixing device detected pressure in the exhaust gas recirculation falls below a predetermined and / or predeterminable threshold and / or the pressure difference between the air pressure in Frischluftzuführstrang and the exhaust gas pressure in the exhaust gas recirculation falls below a predetermined and / or predeterminable pressure difference threshold
• - The low-pressure exhaust gas recirculation, the exhaust gas recirculation train with second compressor, switched by opening the associated valve device, and
• - The high pressure exhaust gas recirculation is switched off by closing a main valve device or operated with the main valve device open parallel to the low pressure exhaust gas recirculation.

According to one another preferred embodiment of the invention Method becomes the pressure difference between the air pressure in the Frischluftzuführstrang and the exhaust gas pressure in the exhaust gas recirculation detected and the power output and / or the rotational speed of the drive mechanism of the second compressor regulated so that the pressure difference minimized and / or a predetermined and / or predefinable pressure difference threshold below.

These preferred embodiment of the invention Procedure is with any engine control systems and procedures combinable and can be parallel or superimposed on them operate. This means that the pressure difference between the pressure of the recirculated exhaust gases and the pressure the fresh air is always optimally regulated, so that the gas mixture can be done more effectively while a motor control system also at the same time the fuel mixture to the requirements performance and optimal emission levels.

• – in einem ersten Verfahrensschritt die elektronische Steuerung eingeschaltet und zum zweiten Verfahrensschritt fortgeschritten wird,
• – in einem zweiten Verfahrensschritt geprüft wird, ob die Hauptventilvorrichtung der Hochdruckabgasrückführung voll geöffnet ist und wenn das Ergebnis negativ ausfällt, die Hochdruckabgasrückführung betrieben und zum sechsten Verfahrensschritt fortgeschritten wird, wo wenn das Ergebnis positiv ausfällt, zur nächsten Abfrage im dritten Verfahrensschritt fortgeschritten wird,
• – im dritten Verfahrensschritt geprüft wird, ob eine erfaßte Abweichung der Abgasrückführungsrate oder der relativen Sauerstoffkonzentration im Einlaßkrümmer (BGR) größer als ein jeweiliger vorgegebener und/oder vorgebbarer Schwellenwert ist und wenn das Ergebnis negativ ausfällt, die Hochdruckabgasrückführung betrieben und zum sechsten Verfahrensschritt fortgeschritten wird, und wenn das Ergebnis positiv ausfällt, zum vierten Verfahrensschritt fortgeschritten wird,
• – im vierten Verfahrensschritt die Niederdruckabgasrückführung betrieben wird, in dem die Ventilvorrichtung der Niederdruckabgasrückführung geöffnet und die Hauptventilvorrichtung geschlossen wird und im fünften Verfahrensschritt die Steuerung der Hochdruckabgasrückführung abgeschaltet wird, oder
• – im sechsten Verfahrensschritt die Hochdruckabgasrückführung betrieben wird, in dem die Ventilvorrichtung der Niederdruckabgasrückführung geschlossen und die Hauptventilvorrichtung geöffnet wird und im siebten Verfahrensschritt die Steuerung der Niederdruckabgasrückführung abgeschaltet wird, und
• – im achten Verfahrensschritt zum Beginn des Verfahrensablaufs verzweigt wird.

The inventive method is further formed in an alternative embodiment so that

• In a first method step, the electronic control is switched on and advanced to the second method step,
• In a second step, it is checked whether the main valve device of the high-pressure exhaust gas recirculation is fully opened and if the result is negative, the high-pressure exhaust gas recirculation is operated and advanced to the sixth step, where the result is positive, the next query in the third step,
• In the third method step, it is checked whether a detected deviation of the exhaust gas recirculation rate or of the relative oxygen concentration in the intake manifold (BGR) is greater than a respective predefined and / or predefinable threshold value and if the result is negative, the high-pressure exhaust gas recirculation is operated and the process proceeds to the sixth method step, and if the result is positive, the fourth step of the procedure is advanced,
• In the fourth method step, the low pressure exhaust gas recirculation is operated, in which the valve device of the low pressure exhaust gas recirculation is opened and the main valve device is closed and in the fifth method step, the control of the high pressure exhaust gas recirculation is switched off, or
• - In the sixth step, the high pressure exhaust gas recirculation is operated, in which the valve device of the low pressure exhaust gas recirculation is closed and the main valve device is opened and in the seventh process step, the control of the low pressure exhaust gas recirculation is switched off, and
• - Branched in the eighth step to the beginning of the procedure.

These alternative embodiment of the invention Procedure is fundamentally different from the previous one Described in that the power output of the drive mechanism and / or the speed of the second compressor with the detected or determined exhaust gas recirculation rate or relative oxygen concentration coupled becomes. Furthermore, it is possible in a further preferred Embodiment of the invention, both preferred embodiments of inventive method superimposed on each other apply.

To Yet another aspect of this invention will become its objects by a control system for controlling the exhaust gas flows the exhaust system according to one of the previously described embodiments solved. This control system can be in a separate Housing be housed or integrated into the engine control become.

The object according to the invention is also achieved, according to a further aspect, by an internal combustion engine having an exhaust system with exhaust gas recirculation (US Pat. 14 ) solved according to one of the previously described embodiments.

Further preferred embodiments of the invention will become apparent from the remaining, in the sub claims mentioned characteristics.

The Invention will be described below in embodiments the accompanying drawings explained. Show it:

1 a schematic arrangement of an exemplary exhaust system according to the invention an internal combustion engine, and

2 a flowchart of a preferred embodiment of the control of the exhaust system according to the invention.

1 shows a schematic arrangement of an exemplary exhaust system according to the invention 15 an internal combustion engine 9 ,

An internal combustion engine used here by way of example 9 is designed as a 6-cylinder V-engine and has an intake manifold 11 and a two-piece exhaust or exhaust manifold 10 on.

The fresh air passes through a Frischluftzuführstrang 17 sucked in by a first compressor 1 , via a preferably controllable and controlled by a control throttle 2 to an air exhaust mixing device 18 from where they are mixed with the recirculated exhaust gases in the intake manifold 11 flows. The air exhaust mixing device 18 is realized in the simplest case simply by a pipe connection point.

The first compressor 1 is through an exhaust-powered turbine 1.1 driven, which is set in rotation by the outflowing hot exhaust gases in the exhaust line. This is a conventional turbocharger, as used in diesel or gasoline engines. Its pumping power or speed can therefore be regulated via a variable position of the turbine blades as in a TGM turbocharger.

Immediately to the exit of the exhaust gases from the exhaust manifold 10 is an exhaust gas recirculation train 13 connected by means of a controllable valve device 3 switched off and switched on or in advantageous embodiments also throttled. The exhaust gases flow over this exhaust gas recirculation line 13 with open valve device 3 in the exhaust gas recirculation 21 and arrive at the air exhaust mixing device 18 where they are mixed with the fresh air and further into the intake manifold 11 stream. In a preferred embodiment, a radiator is included 7 in the exhaust gas recirculation 21 arranged in which the exhaust gases are cooled before they are mixed with the fresh air.

The exhaust fumes after passing the turbine 1.1 happen in an emission control device 12 comprising a catalyst and / or a particulate filter and, for example, at least one damper. After the exhaust gas cleaning, the exhaust gases flow partly over the exhaust gas outlet 16 into the atmosphere and become part of a second exhaust gas recirculation train 14 derived, which is connected by means of a pipe to the exhaust pipe. Since the exhaust gases after passing the exhaust gas purification device 12 have a lower pressure, called the second exhaust gas recirculation train 14 also a low pressure exhaust gas recirculation 14 ,

The low pressure exhaust gas recirculation 14 is by means of a valve device 4 switched off and on or throttled in advantageous embodiments. This valve device 4 is merely an example at the entrance of the low pressure exhaust gas recirculation 14 arranged and may in other advantageous embodiments at another arbitrary position along the low pressure exhaust gas recirculation 14 prior to their merger with the high pressure exhaust gas recirculation 13 be arranged, such. B. also between two dampers.

A cooler 8th cools the recirculated exhaust gases, which then preferably in the cooled state to a second compressor 5 stream. This cooler 8th can be omitted in further preferred embodiments, if, for example, due to the length of the exhaust gas recirculation and the temperature limitations on the part of the intake manifold and / or the second compressor 5 no cooling is required. This second compressor 5 is according to the invention of an electric machine 5.1 driven, whereby its pumping power is independent of the current pressure of the exhaust gases and their mass flow adjustable. Characterized in that the exhaust gases cooled and through the exhaust gas purification device 12 are largely freed of pollutants, they cause a lower wear of the compressor 5 , compressor 5 can therefore be made longer lasting and / or cheaper.

The through the compressor 5 compressed recirculated exhaust gases are in the exhaust gas recirculation 21 where they pass through the cooler arranged there 7 be cooled again. In a further preferred embodiment of the present invention, this cooler 7 therefore in the high-pressure exhaust gas recirculation 13 are arranged, for example, if a further cooling of the recirculated exhaust gases from the low-pressure exhaust gas recirculation 14 is undesirable. A controller 19 controls via the control lines 20 the switching state of the valve devices 2 . 3 and 4 and the power or the rotational speed of the electric machine 5.1 ,

Further, each one (not shown) pressure sensor in the Frischluftzuführstrang 17 and in the exhaust gas recirculation 21 arranged, the measuring signals the controller 19 be supplied.

The control 19 evaluates the measuring signals of these pressure sensors to a pressure difference .DELTA.P between the air pressure Pl in Frischluftzuführstrang 17 and the exhaust gas pressure Pr in the exhaust gas recirculation 21 and to compare this pressure difference or the detected pressure values Pl and / or Pr directly with a predetermined and / or predefinable pressure difference threshold value ΔPmax and / or the threshold value Prmin.

The control 19 or another controller also controls the performance of the first compressor in the conventional manner 17 for example, by varying the position of the turbine blades of the turbine 1.1 ,

The internal combustion engine 9 requires under different loads an adapted amount of air, which is composed of fresh air and the recirculated exhaust gases. For example, an unillustrated air mass sensor detects the volume or mass of the air / exhaust mixture and provides its signals to an engine controller (not shown) that controls fueling and spark timing.

If the controller 19 a pressure value Pr of the recirculated exhaust gases in the exhaust gas recirculation 21 receives, which falls below a predetermined and / or predefinable threshold value Prmin, or the pressure difference .DELTA.P between the air pressure Pl in Frischluftzuführstrang 17 and the exhaust gas pressure Pr in the exhaust gas recirculation 21 falls below a predetermined and / or predeterminable pressure difference threshold .DELTA.Pmax, then it is clear that the pressure performance of the high pressure exhaust gas recirculation 13 is insufficient to a desired mixing rate of the fresh air with the recirculated exhaust gases in the air-Abgasmischvorrichtung 18 to ensure.

In order to increase the pressure of the recirculated exhaust gases to a sufficient value, is now on the low-pressure exhaust gas recirculation 14 switched over by the valve device 3 closed, valve device 4 opened and the electric motor 5.1 is set in motion and its output and / or speed is controlled, so that the above-mentioned detected pressure values are brought into a permissible value range.

In a further advantageous embodiment, the two exhaust gas recirculations 13 and 14 instead of an above-described optional commissioning have a parallel commissioning, whereby the performance of the second compressor 5 and thus the electric motor 5.1 is needed to a lesser extent.

In other words, the inventive adaptation or minimization of the pressure difference .DELTA.P between the air pressure Pl in Frischluftzuführstrang 17 and the exhaust gas pressure Pr in the exhaust gas recirculation 21 is superimposed on an engine control, so that optimized in all operating conditions both optimal mixing of the recirculated exhaust gases with the fresh air and the required operating parameters, in particular the exhaust gas recirculation rate and / or the relative oxygen concentration in the intake manifold. The engine control can in this case according to one of the known methods or according to the invention as under 2 be designed described.

2 shows a flowchart of the control of the exhaust system according to the invention 15 in a preferred embodiment.

In the method step S1, a start of the control of the exhaust system takes place, for example, with the starting of the internal combustion engine 9 can coincide.

In method step S2, the opening degree of the valve device is detected 3 the high pressure exhaust gas recirculation 13 , For this purpose, for example, the position of the valve device forming a throttle valve or in other embodiments of the mass flow of the exhaust gases can be detected. As long as this valve device has not come to its limitation by maximum opening, it is said that the control of exhaust gas recirculation 13 is still in a controllable range and it is controlled this normal exhaust gas recirculation.

When the valve device 3 has reached its full opening, then is advanced to another query in step S3. Here, the error or the amount of the exhaust gas recirculation rate or the relative oxygen concentration in the intake manifold is compared with a predetermined and / or predeterminable threshold value. Within a permissible value range, the high pressure exhaust gas recirculation will still be 13 applied and advanced to step S6, in which the valve device 4 the low pressure exhaust gas recirculation 14 is closed, if it was previously open, and the valve device 3 the high pressure exhaust gas recirculation 13 opened when it was closed before.

In the subsequent method step S7, the control of the closed loop of the high-pressure exhaust gas recirculation takes place 13 , Here, the opening of the valve device 3 For example, be a function of the error of the exhaust gas recirculation rate or the relative oxygen concentration in the intake manifold or the exhaust gas recirculation rate itself. Furthermore, here the control of the electrical machine 5.1 , ie the low-pressure exhaust gas recirculation 14 turned off.

If the error of the exhaust gas recirculation rate or the relative oxygen concentration in the intake manifold in S3 exceeds the predetermined threshold value, then the forced-compression exhaust gas recirculation via the low-pressure exhaust gas recirculation 14 switched. For this purpose, the method step S4 is advanced, in which the valve device 4 the low pressure exhaust gas recirculation 14 is opened when it was previously closed, and the valve device 3 the high pressure exhaust gas recirculation 13 closed if it was open before. Thereafter, the process proceeds to step S5, in which a closed-loop control of the low-pressure exhaust gas recirculation 14 as a function of the error of the exhaust gas recirculation rate or the relative oxygen concentration in the intake manifold or the exhaust gas recirculation rate or the relative oxygen concentration in the intake manifold itself. In addition, here the control of the valve device 3 , ie the high pressure exhaust gas recirculation 13 switched off or put into a standby state.

Both Process steps S7 and S5 lead to a loop, which leads to the beginning of the procedure, so that the respective Closed loop. In step S8 can be queried whether a loop repetition or termination of the procedure is desired.

The relative oxygen concentration in the intake manifold can be determined by the following relationship: BGR = 1 - 0 2 _{A /} O _2REF , where O 2 _{A is} the oxygen concentration in the intake manifold and O _{2REF is} the reference oxygen concentration of the air.

With the exhaust system according to the invention with exhaust gas recirculation The emissions of the internal combustion engine are lowered, a higher Exhaust gas recirculation rate or relative oxygen concentration achieved in the intake manifold, whereby the corresponding Exhaust gas cooler and intake manifold become more durable and the operation of the engine can better on combustion processes be optimized.

LIST OF REFERENCE NUMBERS

1

first compressor

1.1

turbine

2

Valve device Throttle valve of exhaust gas recirculation

3

Main valve device valve device

4

valve device

5

second compressor

5.1

Drive mechanism, electric machine, electric motor

6

Fresh air cooler, Charge air cooler)

7

common Exhaust gas cooler

8th

Exhaust gas cooler the low pressure exhaust gas recirculation

9

Internal combustion engine

10

exhaust manifold

11

intake manifold

12

Exhaust gas purification device, Catalyst, particle filter

13

Exhaust gas return duct rank, first, high pressure exhaust gas recirculation

14

Exhaust gas return duct rank, second, low-pressure exhaust gas recirculation

fifteen

exhaust system

16

exhaust outlet

17

Frischluftzuführstrang

18

Air-exhaust mixer

19

Control system control

20

Control line / s

21

Exhaust gas recirculation

S1 ... S8

steps

pl

air pressure

pr

print in the exhaust gas recirculation

.DELTA.P

pressure difference

Apmax

Pressure difference threshold

Prmin

threshold

DPF

diesel particulate Filter

AGR

Exhaust gas recirculation

BGR

Burned Gas rate, relative oxygen concentration in the intake manifold

02EIN

oxygen concentration in the intake manifold

O2REF

Reference oxygen concentration the air

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 7165540 B2 [0004, 0005]
• US 2002/0112478 A1 [0005]
• - US 7117843 B2 [0006]
• - US 6050095 [0007]
• US 2006/0124115 A1 [0008]

Cited non-patent literature

• - EURO 6 standard [0002]
• - Animal 2 [0002]
• - Am 5 [0002]

Claims (17)

Exhaust system ( 15 ) an internal combustion engine ( 9 ) with exhaust gas recirculation ( 13 . 14 ), with one with a throttle ( 2 ) regulated fresh air supply line ( 17 ), at least one first exhaust gas recirculation line ( 13 ), at least a first turbocharger ( 1 . 1.1 ) with a compressor ( 1 ) and an exhaust gas driven turbine ( 1.1 ), with at least one exhaust gas cleaning device arranged in the exhaust gas flow ( 12 ), characterized in that in at least one exhaust gas recirculation line ( 14 ) at least one second compressor ( 5 ) arranged by a mechanical rotation generating drive mechanism ( 5.1 ) is driven. Exhaust system according to claim 1, characterized in that the power output and / or the rotational speed of the drive mechanism ( 5.1 ) of the second compressor ( 5 ) as a function of operating parameters of the internal combustion engine ( 9 ) is controllable and / or controlled. Exhaust system according to one of the preceding claims, characterized in that the drive mechanism ( 5.1 ) as an electrical machine ( 5.1 ) is trained. Exhaust system according to one of the preceding claims, characterized in that the exhaust gas recirculation line ( 14 ) with second compressor ( 5 ) downstream of the at least one emission control device ( 12 ) to the exhaust system ( 15 ) is connected so that the exhaust gas recirculation line ( 14 ) a low pressure exhaust gas recirculation ( 14 ), and the first exhaust gas recirculation line ( 13 ) downstream of the at least one emission control device ( 12 ) to the exhaust system ( 15 ) is connected so that the exhaust gas recirculation line ( 13 ) a high-pressure exhaust gas recirculation ( 13 ). Exhaust system according to one of the preceding claims, characterized in that the exhaust gas flow through the exhaust gas recirculation line ( 14 ) with second compressor ( 5 ) via a controllable valve device ( 4 ) can be switched on and off and / or throttled. Exhaust system according to one of the preceding claims, characterized in that at least two exhaust gas recirculation strands ( 13 . 14 ) via a respective controllable valve device ( 3 . 4 ) can be switched on and off and / or throttled. Exhaust system according to one of the preceding claims, characterized in that in the Frischluftzuführstrang ( 17 ) and in the exhaust gas recirculation line ( 14 ) with second compressor ( 5 ) is provided in each case a pressure sensor. Exhaust system according to one of the preceding claims, characterized in that at least one valve device ( 2 . 3 . 4 ) is controllable and / or controlled by a controller. Exhaust system according to one of the preceding claims, characterized in that the exhaust gas purification device ( 12 ) has at least one catalyst and / or a particulate filter. Exhaust system according to one of the preceding claims, characterized in that in the Frischluftzuführstrang ( 17 ) and in the exhaust gas recirculation line ( 14 ) with second compressor ( 5 ) at least one cooler ( 6 . 8th ) is provided for cooling the fresh air and / or the recirculated exhaust gases. Exhaust system according to one of the preceding claims 2 to 10, characterized in that as operating parameters of the internal combustion engine ( 9 ) the exhaust gas recirculation rate and / or the relative oxygen concentration in the intake manifold (BGR) is detected by means of a respective detection means. Method for controlling the exhaust system ( 15 ) with exhaust gas recirculation ( 14 ) according to one of the preceding claims, characterized in that the power output of the drive mechanism ( 5.1 ) and / or the speed of the second compressor ( 5 ) as a function of operating parameters of the internal combustion engine ( 9 ) is controlled. A method according to claim 12, characterized in that - when the downstream of an air exhaust mixing device ( 18 ) detected pressure (Pr) in the exhaust gas recirculation ( 21 ) falls below a predetermined and / or predefinable threshold value (Prmin) and / or the pressure difference (ΔP) between the air pressure (Pl) in the Frischluftzuführstrang ( 17 ) and the exhaust pressure (Pr) in the exhaust gas recirculation ( 21 ) falls below a predetermined and / or predefinable pressure difference threshold value (ΔPmax), then the low-pressure exhaust gas recirculation ( 14 ), the exhaust gas recirculation line ( 14 ) with second compressor ( 5 ), by opening the valve device ( 4 ), and - the high-pressure exhaust gas recirculation ( 13 ) by closing a main valve device ( 3 ) or with the main valve open ( 3 ) parallel to the low-pressure exhaust gas recirculation ( 14 ) operated. Method according to one of the preceding claims, characterized in that the pressure difference (ΔP) between the air pressure (Pl) in the Frischluftzuführstrang ( 17 ) and the exhaust pressure (Pr) in the exhaust gas recirculation ( 21 ) and the power output and / or the speed of the drive mechanism ( 5.1 ) of the second compressor ( 5 ) is regulated such that the pressure difference (.DELTA.P) is minimized and / or falls below a predetermined and / or predeterminable pressure difference threshold value (.DELTA.Pmax). Method according to claim 12, characterized in that - in the first method step (S1) the electronic control is switched on and the second method step (S2) is advanced, - in a second method step (S2) it is checked whether the main valve device ( 3 ) of high-pressure exhaust gas recirculation ( 13 ) is fully opened and if the result is negative, the high pressure exhaust gas recirculation ( 13 ) is advanced and the sixth step (S6) is advanced, if the result is positive, the next query in the third step (S3) is advanced, - is checked in the third step (S3), whether a detected deviation of the exhaust gas recirculation rate or the relative oxygen concentration In the intake manifold (BGR) is greater than a respective predetermined and / or predeterminable threshold value and if the result is negative, the high-pressure exhaust gas recirculation ( 13 ) and the sixth step (S6) is advanced, if the result is positive, the fourth step (S4) is advanced, - in the fourth step (S4), the low-pressure exhaust gas recirculation ( 14 ), in which the valve device ( 4 ) of low-pressure exhaust gas recirculation ( 14 ) and the main valve device ( 3 ) is closed and in the fifth method step (S5), the control of the high-pressure exhaust gas recirculation ( 13 ) is switched off, or - in the sixth method step (S6), the high-pressure exhaust gas recirculation ( 13 ), in which the valve device ( 4 ) of low-pressure exhaust gas recirculation ( 14 ) and the main valve device ( 3 ) and in the seventh process step (S7) the control of the low-pressure exhaust gas recirculation ( 14 ) is switched off, and - in the eighth process step (S8) to the beginning of the process flow in the second process step (S2) is branched. Control system ( 19 ) for controlling the exhaust gas flows of the exhaust system ( 15 ) according to any one of the preceding claims. Internal combustion engine with an exhaust system ( 15 ) with exhaust gas recirculation ( 14 ) according to any one of the preceding claims.

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