DE102011005654A1 - Internal combustion engine e.g. heavy oil powered marine diesel engine has exhaust gas bypass pipe which is guided by filter, so that exhaust gas is bypassed over bypass pipe in direction of selective catalytic reduction catalyst converter - Google Patents

Abstract

The engine has supercharger (11) which is connected with particulate filter (14) and selective catalytic reduction (SCR) catalyst converter (15). The effluent stream is adjustable by the exhaust gas bypass pipe (18) over the adjustment device (19). The exhaust gas bypass pipe positioned with reducing agent metering device (16) and hydrolysis catalyst converter (17) is guided by the particulate filter, so that exhaust gas is bypassed over exhaust gas bypass pipe in the direction of SCR catalyst converter.

Description

The invention relates to an internal combustion engine according to the preamble of claim 1.

From the DE 10 2004 027 593 A1 is an internal combustion engine with a single-stage or two-stage exhaust gas turbocharging and an exhaust gas purification via an SCR catalyst known. In a one-stage exhaust turbocharging, the prior art SCR catalytic converter is positioned either downstream of the turbine of the exhaust gas turbocharger or upstream of the turbine of the exhaust gas turbocharger. In a two-stage exhaust gas turbocharger with two exhaust gas turbochargers, the SCR catalytic converter according to this prior art is connected between or after the two turbines of the two exhaust gas turbochargers. Furthermore, it is already known from this prior art to bypass the SCR catalytic converter via a bypass line in order to pass exhaust gas past the SCR catalytic converter in the direction of a turbine of an exhaust gas turbocharger positioned downstream of the SCR catalytic converter. The exhaust gas flow through this bypass line is adjustable via an adjusting device.

Another internal combustion engine is out of the DE 10 2007 061 005 A1 known. According to this prior art, the internal combustion engine also comprises an exhaust gas turbocharger, wherein exhaust gas which has passed a turbine of an exhaust gas turbocharger, then via an oxidation catalyst, after the oxidation catalyst via a particulate filter, subsequently via an SCR catalyst and after the SCR catalyst via another Oxidation catalyst is passed. Furthermore, it is known from this prior art that exhaust gas can be passed over an exhaust gas bypass line on the turbine of the exhaust gas turbocharger and downstream of the turbine oxidation catalyst in the direction of the particulate filter, wherein in this bypass line a Reduktionsmitteldosiereinrichtung and a hydrolysis are arranged.

On this basis, the invention is based on the object to provide a novel internal combustion engine. This object is achieved by an internal combustion engine according to claim 1. According to the invention, the exhaust gas bypass line in which the reducing agent metering device and the hydrolysis catalytic converter are positioned at least around the particulate filter, so that exhaust gas can be conducted via the exhaust gas bypass line at least bypassing the particulate filter in the direction of the SCR catalytic converter.

The invention proposes for the first time an internal combustion engine whose exhaust gas bypass line into which the reducing agent metering device and the hydrolysis catalytic converter are positioned is guided at least around the particle filter. Thus, exhaust gas which is conducted via the exhaust gas bypass line and thus via the reducing agent metering device and the hydrolysis catalytic converter can be passed at least past the particle filter in the direction of the SCR catalytic converter. As a result, the efficiency of the SCR catalyst can be increased. Further, the exhaust gas backpressure generated by the particulate filter facilitates branching of exhaust gas through the exhaust bypass passage in which the reducing agent metering device and the hydrolysis catalyst are positioned.

Preferably, via a further exhaust gas bypass line exhaust gas on the one hand at least bypassing the particulate filter and on the other hand, bypassing the Reduktionsmitteldosiereinrichtung and the hydrolysis in the direction of the SCR catalyst conductive, the exhaust gas flow through the further exhaust gas bypass line via a further adjustment is adjustable. The further exhaust gas bypass line, with which at least both the particle filter and the reducing agent metering device and the hydrolysis catalytic converter can be bypassed, can be used to further increase the efficiency of the SCR catalytic converter.

According to an advantageous development of the invention, charge air can be supplied via a charge air bypass line starting from a compressor of the respective exhaust gas turbocharger of the exhaust gas bypass line in which the reducing agent metering device and the hydrolysis catalytic converter are positioned, namely upstream of the reducing agent metering device and of the hydrolysis catalytic converter. By means of the charge air guided via the charge air bypass line, the exhaust gas, which is guided via the exhaust gas bypass line, in which the reducing agent metering device and the hydrolysis catalytic converter is positioned, can be mixed with charge air so as to precisely adjust the temperature of the exhaust gas conducted via the reducing agent metering device and the hydrolysis catalytic converter and to increase the effectiveness of the Reduktionsmitteldosiereinrichtung and the hydrolysis and thus the efficiency of the SCR catalyst.

Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be explained in more detail with reference to the drawing, without being limited thereto. Showing:

1 a schematic representation of a supercharged internal combustion engine according to a first embodiment of the invention;

2 a schematic representation of a supercharged internal combustion engine according to a second embodiment of the invention;

3 a schematic representation of a supercharged internal combustion engine according to a third embodiment of the invention;

4 a schematic representation of a supercharged internal combustion engine according to a fourth embodiment of the invention;

5 a schematic representation of a supercharged internal combustion engine according to a fifth embodiment of the invention;

6 a schematic representation of a supercharged internal combustion engine according to a sixth embodiment of the invention;

7 a schematic representation of a supercharged internal combustion engine according to a seventh embodiment of the invention;

8th a schematic representation of a supercharged internal combustion engine according to an eighth embodiment of the invention;

9 a schematic representation of a supercharged internal combustion engine according to a ninth embodiment of the invention; and

10 a schematic representation of a supercharged internal combustion engine according to a tenth embodiment of the invention.

The invention relates to an internal combustion engine, in particular a marine diesel engine operated with heavy oil. Heavy fuel marine diesel engines have the peculiarity that the fuel used by them, heavy fuel oil, has a relatively high sulfur content. Undesirable reactions of sulfur oxides with ammonia can lead to deposits that affect the effectiveness of the exhaust gas purification. In particular, the undesirable reactions associated with too low temperatures occur. This can be avoided in the internal combustion engine according to the invention.

1 shows an embodiment of an internal combustion engine 10 with a one-stage exhaust charging via an exhaust gas turbocharger 11 , where from the exhaust gas turbocharger 11 a turbine 12 and a compressor 13 are shown. Exhaust gas leaving the engine is transmitted via the turbine 12 the exhaust gas turbocharger 11 guided and in the turbine 12 relaxed, thereby recovering energy for driving the compressor 13 is used to the internal combustion engine 10 to compress supplied charge air. In the 1 shown internal combustion engine 10 also has a particle filter in the exhaust gas flow 14 and an SCR catalyst 15 , where in 1 the particle filter 14 downstream of the turbine 12 and the SCR catalyst 15 downstream of the particulate filter 14 is arranged.

Furthermore, the internal combustion engine has the 1 via a reducing agent metering device 16 and a hydrolysis catalyst 17 that is in an exhaust bypass line 18 are arranged, wherein in the context of the invention, the exhaust gas bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned, at least around the particulate filter 14 is guided around so that the exhaust bypass line 18 and thus the reducing agent metering device 16 and the hydrolysis catalyst 17 Guided exhaust gas bypassing the particulate filter 14 towards the SCR catalyst 15 is conductive. The exhaust gas flow through the bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 can be positioned, via an adjusting device 19 be set.

The in the bypass line 18 positioned hydrolysis catalyst 17 causes effective evaporation and accelerated reaction of the via the Reduktionsmitteldosiereinrichtung 16 in the over the exhaust bypass line 18 Guided exhaust gas flow introduced reducing agent for the SCR exhaust gas purification in the SCR catalyst 15 so that an effective operation of the SCR catalyst 15 can be guaranteed. By the positioning of the reducing agent metering device 16 and the hydrolysis catalyst 17 in the particle filter 14 immediate bypass line 18 will prevent the particulate filter 14 by adding the reducing agent upstream of the particulate filter 14 as well as blocked by deposits. The invention can therefore the effectiveness of the particulate filter 14 and the SCR catalyst 15 be increased.

2 shows an embodiment of an internal combustion engine according to the invention, in which the bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned, both around the particle filter 14 as well as around the turbine 12 of the catalytic converter 11 is guided around. Thus, exhaust gas can be applied both to the turbine 12 the exhaust gas turbocharger 11 as well as on the particle filter 14 Passed over to this via this exhaust bypass line 18 introduced led exhaust reducing agent and via the hydrolysis catalyst 17 lead and then lead in the direction of the SCR catalyst.

With regard to the remaining details, the embodiment of the 2 with the Embodiment of 1 match, so that the comments on the embodiment of 1 is referenced.

3 shows a development of the embodiment of 2 , in which besides the exhaust gas bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned, another exhaust bypass line 20 is present, over the exhaust one hand, bypassing the turbine 12 and the particulate filter 14 and on the other hand, bypassing the Reduktionsmitteldosiereinrichtung 16 and the hydrolysis catalyst 17 towards the SCR catalyst 15 is conductive. The exhaust gas flow through this further exhaust gas bypass line 20 is about a further adjustment 21 adjustable. Exact coordination of the exhaust gas volume flows and temperatures through the two bypass lines 18 and 20 the efficiency of the exhaust gas purification can be further increased. The bypass line 20 of the 3 can also in the embodiment of 1 be used, in which case the exhaust gas bypass line 20 parallel to the exhaust bypass line 18 is switched and only the particle filter 14 bypasses.

4 shows a further development of the embodiment of 2 , wherein in the embodiment of the 4 via a charge air bypass line 22 Charge air from compressor 13 , namely in 4 downstream of the compressor 13 and upstream of the engine 10 , the exhaust bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned, namely according to 4 upstream of the reducing agent metering device 16 and upstream of the hydrolysis catalyst 17 , The charge air flow through this charge air bypass line 22 is via an adjusting device 23 adjustable. Through this admixture of charge air in the on the exhaust gas bypass line 18 on the particle filter 14 Passed exhaust gas can change the temperature of the exhaust bypass line 18 guided exhaust gas can be accurately adjusted to a desired level. This represents a further increase in efficiency in the area of the SCR catalyst 15 and thus the emission control possible. In addition, you get the option that the charge air can be used as dosing air.

5 shows an embodiment of the invention, which the features of the embodiments of the 3 and 4 combined, in which therefore both the further exhaust gas bypass line 20 as well as the charge air bypass line 22 with the respective adjustment 21 . 23 is available. Such a combination is to increase the efficiency of the SCR catalyst 15 particularly preferred, it being noted that such a combinatorial use of the further exhaust gas bypass line 20 and the charge air bypass line 22 also in the embodiment of 1 can be used, in which the bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned, excluding the particulate filter 14 and not the turbine 12 the exhaust gas turbocharger 11 bypasses.

6 shows an embodiment in which it is a development of the internal combustion engine 10 of the 1 is, with the charge air bypass line 22 with the appropriate adjustment 23 is provided to charge air of the exhaust gas bypass line 18 upstream of the reducing agent metering device 16 supply. It is in contrast to the embodiments of the 4 and 5 the charge air upstream of the compressor 13 the exhaust gas turbocharger 11 and not as in the embodiments of 4 and 5 downstream of the compressor 13 the exhaust gas turbocharger 11 via the charge air bypass line 22 towards the exhaust bypass line 18 directed. To a simplified supply of the charge air in the exhaust gas bypass line 18 to enable, however, is the variant of 4 and 5 into which the charge air downstream of the compressor 13 is branched off, preferably.

1 to 6 is common that the respective internal combustion engine has a single-stage turbocharger. In contrast show 7 to 10 Embodiments of internal combustion engines with a multi-stage, namely two-stage, exhaust gas turbocharging, and therefore in addition to the exhaust gas turbocharger 11 another exhaust gas turbocharger 24 with a turbine 25 and a compressor 26 is available.

Both turbine 12 the exhaust gas turbocharger 11 it is then a high-pressure turbine and the turbine 25 the exhaust gas turbocharger 24 around a low-pressure turbine. Accordingly, it is the compressor 13 the exhaust gas turbocharger 11 around a high pressure compressor and the compressor 26 the exhaust gas turbocharger 24 around a low-pressure compressor.

In the embodiments of the 7 to 9 are the particle filter 14 and the SCR catalyst 15 each between the two turbines 12 and 25 the two turbochargers 11 and 24 in turn, such that the SCR catalyst 15 downstream of the particulate filter 14 is positioned.

In the internal combustion engine 10 of the 7 bypasses the exhaust bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned, excluding the particulate filter 14 ,

In 8th By contrast, bypasses the exhaust gas bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are positioned both the particle filter 14 as well as the high-pressure turbine turbine 12 the exhaust gas turbocharger 11 , In 8th is in the exhaust bypass line 18 via the charge air bypass line 22 downstream of the high pressure compressor 13 the exhaust gas turbocharger 11 branches off, in accordance with the embodiments of the 4 and 5 Charge air for temperature control via the exhaust gas bypass line 18 guided exhaust gas in the same einbringbar.

In the embodiment of 9 which is a development of the embodiment of 8th shows, in addition, the further exhaust gas bypass line 20 present over the exhaust both at the high pressure turbine 12 and the particulate filter 14 as well as at the Reduktionsmitteldosiereinrichtung 16 and the hydrolysis catalyst 17 over in the direction of the SCR catalyst 15 can be directed.

Of course, the charge air bypass line could 22 according to the 8th and 9 also branch between or before the compressors.

10 shows a further embodiment of an internal combustion engine 10 with a two-stage turbocharger over two turbochargers 11 and 24 , wherein, in contrast to the embodiments of the 7 to 9 the particle filter 14 and the particle filter 14 downstream SCR catalyst 15 but not between the two turbines 12 and 25 but rather downstream of the low pressure turbine turbine 25 the exhaust gas turbocharger 24 , It bypasses in 10 the exhaust bypass line 18 in which the reducing agent metering device 16 and the hydrolysis catalyst 17 are arranged, again only the particulate filter 14 , In contrast, however, it is also possible, the bypass line 18 so that the turbine too 25 of the turbocharger 24 can be bypassed. Likewise, in 10 the further exhaust gas bypass line 20 and the charge air bypass line 22 be used, the charge air bypass line 22 then downstream of the compressor 26 or also downstream of the compressor 13 Charge air branch off and the exhaust gas bypass line 18 can supply, namely upstream of the Reduktionsmitteldosiereinrichtung 16 ,

All embodiments have in common that via an exhaust gas bypass line 18 Exhaust gas on the particle filter 14 can be passed over to the particle filter 14 Passed exhaust gas via a Reduktionsmitteldosiereinrichtung 16 and a hydrolysis catalyst 17 and then the SCR catalyst 15 be forwarded. As a result, the effectiveness of the exhaust gas purification can be increased. On the one hand is a blocking of the exhaust particulate filter 14 avoided, on the other hand, an effective implementation of the reducing agent for the SCR exhaust gas purification in the SCR catalyst 15 be guaranteed.

Complete decomposition of the liquid reductant into the gaseous products in a bypass at optimal conditions and subsequent recirculation to the SCR catalyst reduces the risk of deposit formation on the SCR catalyst associated with heavy oil operation. This means that the minimum use temperature for the SCR catalyst may decrease with sulfur-containing fuels and that the temperature window for SCR operation may become larger.

LIST OF REFERENCE NUMBERS

10

Internal combustion engine

11

turbocharger

12

turbine

13

compressor

14

particulate Filter

15

SCR catalyst

16

Reduktionsmitteldosiereinrichtung

17

hydrolysis catalyst

18

Exhaust bypass line

19

adjustment

20

Exhaust bypass line

21

adjustment

22

Charge air bypass line

23

adjustment

24

turbocharger

25

turbine

26

compressor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004027593 A1 [0002]
• DE 102007061005 A1 [0003]

Claims (6)

Internal combustion engine, in particular a marine diesel engine operated with heavy oil, with an at least single-stage turbocharger over at least one exhaust gas turbocharger ( 11 . 24 ), and with an exhaust gas purification via a particulate filter ( 14 ) and an SCR catalyst ( 15 ), and with one together with a reducing agent metering device ( 16 ) in an exhaust gas bypass line ( 18 ) positioned hydrolysis catalyst ( 17 ), wherein the exhaust gas flow through the exhaust gas bypass line ( 18 ) via an adjusting device ( 19 ) is adjustable, characterized in that the exhaust gas bypass line ( 18 ) in which the reducing agent metering device ( 16 ) and the hydrolysis catalyst ( 17 ), at least around the particulate filter ( 14 ) is guided around so that via the exhaust gas bypass line ( 18 ) Exhaust gas at least bypassing the particulate filter ( 14 ) in the direction of the SCR catalyst ( 15 ) is conductive. Internal combustion engine according to claim 1, characterized in that the exhaust gas bypass line ( 18 ) in which the reducing agent metering device ( 16 ) and the hydrolysis catalyst ( 17 ), both around the particle filter ( 14 ) as well as a turbine ( 12 ) is guided around an exhaust gas turbocharger so that via the exhaust gas bypass line ( 18 ) Exhaust bypassing the turbine ( 12 ) of the respective exhaust gas turbocharger and the particulate filter ( 14 ) in the direction of the SCR catalyst ( 15 ) is conductive. Internal combustion engine according to claim 1 or 2, characterized by a further exhaust gas bypass line ( 20 ), on the exhaust gas on the one hand, bypassing the particulate filter ( 14 ) and on the other hand, bypassing the Reduktionsmitteldosiereinrichtung ( 16 ) and the hydrolysis catalyst ( 17 ) can be conducted in the direction of the SCR catalyst, wherein the exhaust gas flow through the further exhaust gas bypass line via a further adjusting device ( 21 ) is adjustable. Internal combustion engine according to one of claims 1 to 3, characterized by a charge air bypass line ( 22 ), via the charge air from a compressor ( 13 ) of the respective exhaust gas turbocharger exhaust gas bypass line ( 18 ) in which the reducing agent metering device ( 16 ) and the hydrolysis catalyst ( 17 ), namely upstream of the reducing agent metering device ( 16 ) and the hydrolysis catalyst ( 17 ), wherein the charge air flow through the charge air bypass line ( 22 ) via an adjusting device ( 23 ) is adjustable Internal combustion engine according to one of claims 1 to 4, characterized by a multi-stage exhaust gas turbocharger, wherein the particulate filter ( 14 ) and the SCR catalyst ( 15 ) between two turbines ( 12 . 25 ), namely between a high-pressure turbine and a low-pressure turbine, of two exhaust gas turbochargers ( 11 . 24 ) are switched. Internal combustion engine according to claim 5, characterized in that the exhaust gas bypass line ( 18 ) in which the reducing agent metering device ( 16 ) and the hydrolysis catalyst ( 17 ) are positioned around the particulate filter ( 14 ) and the high-pressure turbine positioned upstream of the particulate filter ( 17 ) is guided around.

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