DE102008035553B4 - Internal combustion engine with an exhaust gas recirculation device - Google Patents

Abstract

Internal combustion engine (1) having an exhaust gas recirculation device (2), wherein the internal combustion engine (1) has an exhaust gas purification device (4) for purifying an exhaust gas of the internal combustion engine (1) and a bypass (5) for the first exhaust gas purification device (4 ), wherein the bypass (5) via a first exhaust gas recirculation line (6) exhaust gas connected to an intake tract (7) of the internal combustion engine (1) and wherein in the first exhaust gas recirculation line (6), a first valve (8) is arranged, characterized in that - an exhaust gas turbocharger (9) is provided with a turbine (10) arranged upstream of the first exhaust gas purification device (4) in the exhaust line (3) and a compressor (11) arranged in the intake section (7), wherein - the exhaust gas recirculation device (2) four valves (8, 13, 15, 16), wherein - the exhaust line (3) in the flow direction of the exhaust gas behind the turbine (10) and in front of the bypass (5) via ei ne second exhaust gas recirculation line (14), in which the second valve (13) is arranged, exhaust gas leading to the first exhaust gas recirculation line (6) is connectable and - the first exhaust gas recirculation line (6) via a third exhaust gas recirculation line (17), in which the third valve ( 15) is arranged in the flow direction of the exhaust gas behind the first valve (8) and the second valve (13) with the intake duct (7) in the flow direction of the fresh air behind the throttle valve (29 ') is connectable, - between a branch of the third Exhaust gas recirculation line (17) in the first exhaust gas recirculation line (6), the fourth valve (16) is arranged and - the first exhaust gas recirculation line (6) opens in the flow direction of the fresh air before the compressor (11) in the intake tract (7).

Description

The invention relates to an internal combustion engine having an exhaust gas recirculation device with the features of the preamble of patent claim 1.

The technical environment of the invention is based on the translation of the European patent specification German Offenlegungsschrift DE 60 2004 004 947 T2 , the American publication US 2006/0 236 693 A1 and the German Offenlegungsschrift DE 103 49 129 A1 pointed. These three writings each deal with a turbocharged internal combustion engine with an exhaust gas recirculation and an exhaust gas purification.

A disadvantage of the generic design is that exhaust gas recirculation is not possible in the entire engine map with high exhaust gas recirculation rates.

Object of the present invention is to show an internal combustion engine with an exhaust gas recirculation device, with an exhaust gas recirculation in almost the entire engine map with high exhaust gas recirculation rates is possible.

This object is solved by the features in the characterizing part of patent claim 1.

Due to the configuration according to the invention, an exhaust gas recirculation is possible almost in the entire engine map with high exhaust gas recirculation rates. In addition, there is an improved service life for the Abgasreinigung-, or exhaust aftertreatment system, especially when the exhaust aftertreatment system is a NO _x -Speicherkat. In addition, the inventive design is particularly well suited for gasoline engines with supercharging, especially in stratified operation, since the fuel consumption and the raw emissions are reduced. Another advantage is the particularly compact design.

The embodiments according to claims 2 to 6 are particularly preferred developments of the invention.

In the following the invention with reference to a particularly preferred embodiment in four figures is explained in more detail.

1 shows a schematic representation of an internal combustion engine with an exhaust gas recirculation device according to the invention.

2 shows a three-dimensional view of a valve block according to the invention.

3 shows a three-dimensional rear view of a valve block according to the invention.

4 shows a diagram of an engine map with different exhaust gas recirculation rates.

Below, the same reference numerals apply to the same components in all figures.

1 shows a schematic representation of an internal combustion engine 1 with four cylinders represented by circles, with an intake tract 7 and an exhaust system 3 that has an exhaust gas recirculation facility 2 features. The intake tract 7 consists essentially of unnumbered pipes, in which a fresh air is conveyed in the direction of the cylinder. The exhaust system 3 with the exhaust gas recirculation device 2 also consists essentially of unnumbered pipes in which exhaust gas is conveyed away from the cylinders.

During operation of the internal combustion engine 1 Fresh air first flows over an intake silencer 24 in the intake tract 7 and then flows through a throttle valve 29 , Subsequently, the fresh air enters a compressor 11 an exhaust gas turbocharger 9 , in which the fresh air is compressed and further pumped. Subsequently, the heated by the compression fresh air in a charge air cooler 19 cooled. Next she flows through another throttle 29 ' and then flows into an unnumbered fresh air collector, from which the fresh air into the four cylinders of the internal combustion engine 1 flows.

After combustion of the fresh air with a fuel in the cylinders, the exhaust gas flows into an unnumbered exhaust manifold and further through a turbine 10 the exhaust gas turbocharger 9 , Further, the exhaust gas flows through a second exhaust gas purification device 22 , For example, a three-way catalyst and further by a first exhaust gas purification device 4 , For example, a NO _x storage catalyst (nitrogen oxide storage catalyst) and / or a SCR catalyst (Selective Catalytic Reaction) and then into a center muffler 20 and a rear silencer 21 , Next, the first exhaust gas purification device 4 a bypass 5 in which a first and a second shut-off element 18 . 18 ' are arranged. The shut-off elements 18 . 18 ' are from a control unit 23 controllable. Between the shut-off elements 18 . 18 ' is the bypass 5 via a first exhaust gas recirculation line 6 and a third exhaust gas recirculation line 17 with the intake tract 7 in the flow direction of the fresh air in front of the compressor 11 connected exhaust gas.

According to the invention, the exhaust gas turbocharger 9 with the in the exhaust system 3 in the flow direction before the first exhaust gas purification device 4 arranged turbine 10 and in the intake tract 7 arranged compressor 11 intended. Next, the exhaust gas recirculation device 2 four valves 8th . 13 . 15 . 16 on, with the exhaust system 3 in the flow direction of the exhaust gas behind the turbine 10 and before the bypass 5 via a second exhaust gas recirculation line 14 in which the second valve 13 is arranged exhaust-carrying with the first exhaust gas recirculation line 6 is connectable. Furthermore, the first exhaust gas recirculation line 6 via a third exhaust gas recirculation line 17 in which the third valve 15 is arranged, in the flow direction of the exhaust gas behind the first valve 8th and the second valve 13 with the intake tract 7 in the flow direction of the fresh air behind the throttle 29 ' connectable. Next is between a branch of the third exhaust gas recirculation line 17 in the first exhaust gas recirculation line 6 arranged the fourth valve and the first exhaust gas recirculation line 6 opens in the flow direction of the fresh air in front of the compressor 11 in the intake tract 7 ,

The valves and throttle valves may be, for example, conventional butterfly valves, exhaust valves, poppet valves, valves, rotary valves, etc.

Particularly preferred are the four valves 8th . 13 . 15 . 16 in a single valve block 12 arranged. Again preferred are the first and second valves 8th . 13 adjustable or controllable and the third and the fourth valve 15 . 16 switchable valves. Particularly preferred are the third and the fourth valve 15 . 16 shown as a single switching valve. For particularly low emissions during operation of the internal combustion engine is in the bypass 5 in the flow direction of the exhaust gas at least before the first exhaust gas recirculation line 6 a shut-off element 18 intended for the exhaust gas. In a further embodiment, behind the first exhaust gas recirculation line 6 in the flow direction of the exhaust gas, a second shut-off element 18 ' be provided. For cooling of recirculated exhaust gas is in the second exhaust gas recirculation line 14 in the flow direction of the exhaust gas before the second valve 13 a gas cooler provided.

2 shows a three-dimensionally illustrated front view of a inventively designed valve block 12 , In the front view of the valve block 12 are the first valve 8th , the third valve 15 , the fourth valve 16 and the second valve 13 recognizable. The inlet directions of the exhaust gas in the valve block 12 are through on the valve block 12 directed arrows shown. The exhaust gases leave the valve block 12 through the third and the fourth valve 15 . 16 , The flow directions are in turn indicated by arrows coming from the valve block 12 show away, shown schematically.

3 shows a three-dimensionally illustrated rear view of the valve block 12 , Visible are again the first valve 8th and the second valve 13 as well as the third valve 15 and the fourth valve 16 , The direction of entry of the exhaust gas into the second valve 13 is in turn by one in the direction of the valve block 12 directed arrow shown. The outflow direction of the exhaust gas from the valve 16 is again shown by an arrow coming from the valve block 12 points away.

4 shows in a diagram an engine map with different exhaust gas recirculation rates, wherein on the Y-axis, the specific work w _e in kilojoules / dm ³ in the range of 0 to 2 is shown. About the X-axis, the speed of the engine from 0 to 7000 revolutions is shown. As a curve 25 a torque curve of the internal combustion engine is shown. The first graph 26 stands for a heavy vehicle with an automatic transmission, the second graph 27 stands for a light, equipped with a manual transmission vehicle. In the range from about 800 to 4700 rpm, with a specific work w _e between 0 and 0.4, an exhaust gas recirculation rate of> = 20% is possible in this exemplary embodiment due to the embodiment according to the invention. Further, by the inventive design in this embodiment in a speed range of about 800 to 4700 1 / min at a specific work of 0.4 to 0.8, an exhaust gas recirculation rate of 5 to 10% possible.

• – Die Abgasrückführung ist im gesamten Brennkraftmaschinenkennfeld mit hoher Abgasrückführrate möglich.
• – Es ergibt sich eine verbesserte Lebensdauer für die Abgasreinigungsanlage, insbesondere bei Einsatz eines NO_x-Speicherkatalysators und/oder eines SCR-Katalysators.
• – Die Erfindung ist insbesondere für Otto-Brennkraftmaschinen, aber auch für andere Brennverfahren, wie z. B. dem Diesel-Brennverfahren geeignet, die im Schichtbetrieb und gleichzeitig mit Abgasturboaufladung betrieben werden.
• – Weiter werden der Brennstoffverbrauch sowie die Rohemissionen reduziert.
• – Durch die Zusammenfassung des ersten Ventils 8, des zweiten Ventils 13, des dritten Ventils 15 und des vierten Ventils 16 in einen einzigen Ventilblock 12 wird eine extrem kompakte Bauform erzielt.

In summary, the inventive design of the internal combustion engine with an exhaust gas recirculation device yields the following advantages:

• - The exhaust gas recirculation is possible in the entire engine map with high exhaust gas recirculation rate.
• - It results in an improved life for the emission control system, especially when using a NO _x storage catalytic converter and / or an SCR catalyst.
• - The invention is particularly for gasoline engines, but also for other combustion processes, such. B. the diesel combustion process suitable, which are operated in stratified operation and simultaneously with turbocharging.
• - Further reduces fuel consumption and raw emissions.
• - By the summary of the first valve 8th , the second valve 13 , the third valve 15 and the fourth valve 16 in a single valve block 12 an extremely compact design is achieved.

The switching strategy of the valves 8th . 13 . 15 . 16 can be designed depending on the operating condition of the engine based on the respective required functional requirements.

LIST OF REFERENCE NUMBERS

1

Internal combustion engine

2

Exhaust gas recirculation device

3

exhaust gas line

4

first exhaust gas purification device

5

bypass

6

first exhaust gas recirculation line

7

intake system

8th

first valve

9

turbocharger

10

turbine

11

compressor

12

manifold

13

second valve

14

second exhaust gas recirculation line

15

third valve

16

fourth valve

17

third exhaust gas recirculation line

18

shut-off

18 '

second shut-off element

19

Intercooler

20

middle silencer

21

silencer

22

second exhaust gas purification device

23

control unit

24

Ansauggeräuschdämpfer

25

torque curve

26

first graph

27

second graph

28

gas cooler

29, 29 '

throttle

Claims (6)

Internal combustion engine ( 1 ) with an exhaust gas recirculation device ( 2 ), wherein the internal combustion engine ( 1 ) an exhaust line ( 3 ) with a first exhaust gas purification device ( 4 ) for cleaning an exhaust gas of the internal combustion engine ( 1 ) and a bypass ( 5 ) for the first exhaust gas purification device ( 4 ), whereby the bypass ( 5 ) via a first exhaust gas recirculation line ( 6 ) with an intake tract ( 7 ) of the internal combustion engine ( 1 ) and wherein in the first exhaust gas recirculation line ( 6 ) a first valve ( 8th ), characterized in that - an exhaust gas turbocharger ( 9 ) with a in the exhaust line ( 3 ) in the flow direction in front of the first exhaust gas purification device ( 4 ) arranged turbine ( 10 ) and one in the intake tract ( 7 ) unordered compressors ( 11 ) is provided, wherein - the exhaust gas recirculation device ( 2 ) four valves ( 8th . 13 . 15 . 16 ), wherein - the exhaust gas line ( 3 ) in the flow direction of the exhaust gas behind the turbine ( 10 ) and before the bypass ( 5 ) via a second exhaust gas recirculation line ( 14 ), in which the second valve ( 13 ) is arranged, exhaust gas leading to the first exhaust gas recirculation line ( 6 ) is connectable and - the first exhaust gas recirculation line ( 6 ) via a third exhaust gas recirculation line ( 17 ), in which the third valve ( 15 ) is arranged, in the flow direction of the exhaust gas behind the first valve ( 8th ) and the second valve ( 13 ) with the intake tract ( 7 ) in the flow direction of the fresh air behind the throttle valve ( 29 ' ) is connectable, wherein - between a branch of the third exhaust gas recirculation line ( 17 ) in the first exhaust gas recirculation line ( 6 ) the fourth valve ( 16 ) is arranged and - the first exhaust gas recirculation line ( 6 ) in the flow direction of the fresh air before the compressor ( 11 ) in the intake tract ( 7 ) opens. Internal combustion engine according to claim 1, characterized in that the four valves ( 8th . 13 . 15 . 16 ) in a single valve block ( 12 ) are arranged. Internal combustion engine according to claim 1 or 2, characterized in that the first and the second valve ( 8th . 13 ) are regular or controllable. Internal combustion engine according to one of the claims 1 to 3, characterized in that the third and the fourth valve ( 15 . 16 ) are switchable. Internal combustion engine according to claim 4, characterized in that the third and the fourth valve ( 15 . 16 ) are a single switching valve. Internal combustion engine according to one of the claims 1 to 5, characterized in that in the bypass ( 5 ) in the flow direction of the exhaust gas at least before the first exhaust gas recirculation line ( 6 ) a shut-off element ( 18 ) is provided for the exhaust gas.

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