CH706295A2 - Combustion engine e.g. heavy oil operated marine diesel combustion engine has reducing agent metering device and hydrolysis catalyst converter that are arranged so that exhaust gas is fed into converter by avoiding filter - Google Patents

Abstract

The engine has selective catalytic reduction (SCR) catalyst converter (15) and particulate filter (14). A reducing agent metering device (16) and hydrolysis catalyst converter (17) are positioned in an exhaust gas bypass pipe (18). The effluent stream in exhaust gas bypass pipe is adjusted by amplifier express device (19). The reducing agent metering device and hydrolysis catalyst converter are positioned around the particulate filter so that the exhaust gas supplied over exhaust gas bypass pipe is fed into SCR catalyst converter by avoiding particulate filter.

Description

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

From DE 10 2004 027 593 A1, an internal combustion engine with a single-stage or two-stage turbocharging and an exhaust gas purification via an SCR catalyst is known. In a single stage turbocharger, the SCR catalyst of this prior art 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 known from DE 10 2007 061 005 A1. 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, is guided at least around the particle filter, so that exhaust gas can be conducted via the exhaust gas bypass line, at least bypassing the particle filter in the direction of the SCR catalytic converter.

With the invention, an internal combustion engine is proposed for the first time, the exhaust gas bypass line, in which the Reduktionsmitteldosiereinrichtung and the hydrolysis are positioned, at least guided around the particulate 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 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 Abgasbypassleitung is adjustable via a further adjustment. 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 embodiment of the invention is charge air 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 Reduktionsmitteldosiereinrichtung and the hydrolysis catalyst are positioned, feedable, namely upstream of the Reduktionsmitteldosiereinrichtung and the hydrolysis. 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 described, without being limited thereto, with reference to the drawings. Showing: <Tb> FIG. 1: <sep> is a schematic representation of a supercharged internal combustion engine according to a first embodiment of the invention; <Tb> FIG. 2: <sep> is a schematic representation of a supercharged internal combustion engine according to a second embodiment of the invention; <Tb> FIG. 3 is a schematic diagram of a supercharged internal combustion engine according to a third embodiment of the invention; <Tb> FIG. 4 is a schematic diagram of a supercharged internal combustion engine according to a fourth embodiment of the invention; <Tb> FIG. 5 is a schematic diagram of a supercharged internal combustion engine according to a fifth embodiment of the invention; <Tb> FIG. 6 is a schematic diagram of a supercharged internal combustion engine according to a sixth embodiment of the invention; <Tb> FIG. 7 is a schematic diagram of a supercharged internal combustion engine according to a seventh embodiment of the invention; <Tb> FIG. 8 is a schematic diagram of a supercharged internal combustion engine according to an eighth embodiment of the invention; <Tb> FIG. 9 is a schematic diagram of a supercharged internal combustion engine according to a ninth embodiment of the invention; and <Tb> FIG. 10 is a schematic diagram 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 inventive internal combustion engine.

Fig. 1 shows an embodiment of an internal combustion engine 10 with a single-stage exhaust charging via an exhaust gas turbocharger 11, wherein the exhaust gas turbocharger 11, a turbine 12 and a compressor 13 are shown. Exhaust gas leaving the internal combustion engine is guided via the turbine 12 of the exhaust gas turbocharger 11 and expanded in the turbine 12, in which case energy used for driving the compressor 13 is used to compress the charge air to be supplied to the internal combustion engine 10. The internal combustion engine 10 shown in FIG. 1 also has a particle filter 14 and an SCR catalytic converter 15 in the exhaust gas flow. In FIG. 1, the particle filter 14 is arranged downstream of the turbine 12 and the SCR catalytic converter 15 downstream of the particle filter 14.

Furthermore, the internal combustion engine of FIG. 1 has a reducing agent metering device 16 and a hydrolysis catalytic converter 17, which are arranged in an exhaust gas bypass line 18, wherein in the context of the invention the exhaust gas bypass line 18, in which the reducing agent metering device 16 and the hydrolysis catalytic converter 17 are positioned, at least is guided around the particulate filter 14, so that via the exhaust gas bypass line 18 and thus the Reduktionsmitteldosiereinrichtung 16 and the hydrolysis catalyst 17 guided exhaust gas, bypassing the particulate filter 14 in the direction of 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 catalytic converter 17 are positioned, can be adjusted via an adjusting device 19.

Positioned in the bypass line 18 hydrolysis catalyst 17 causes effective evaporation and accelerated implementation of the Reduktionsmitteldosiereinrichtung 16 in the guided over the exhaust gas bypass line 18 exhaust gas flow 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 ensured. The positioning of the reducing agent metering device 16 and the hydrolysis catalytic converter 17 in the bypass line 18 bypassing the particle filter 14 prevents the particle filter 14 from being blocked by metering in the reducing agent upstream of the particle filter 14 and by deposits. Thus, the effectiveness of the particulate filter 14 and the SCR catalyst 15 can be increased by the invention.

Fig. 2 shows an embodiment of an inventive internal combustion engine, in which the bypass line 18, in which the Reduktionsmitteldosiereinrichtung 16 and the hydrolysis 17 are positioned, both around the particulate filter 14 and around the turbine 12 of the catalytic converter 11 is guided around. Thus, exhaust gas can be passed both to the turbine 12 of the exhaust gas turbocharger 11 and the particulate filter 14 to introduce into the exhaust gas guided via this exhaust gas bypass line 18 and lead over the hydrolysis catalyst 17 and then to lead in the direction of the SCR catalyst.

With regard to the remaining details, the embodiment of FIG. 2 agrees with the exemplary embodiment of FIG. 1, so that reference is made to the explanations concerning the exemplary embodiment of FIG. 1.

Fig. 3 shows a development of the embodiment of Fig. 2, in which in addition to the exhaust gas bypass line 18, in which the Reduktionsmitteldosiereinrichtung 16 and the hydrolysis 17 are positioned, a further Abgasbypassleitung 20 is present on the exhaust gas on the 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 in the direction of the SCR catalyst 15 is conductive. The exhaust gas flow through this further exhaust gas bypass line 20 is adjustable via a further adjusting device 21. Exact tuning 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 FIG. 3 can also be used in the embodiment of FIG. 1, in which case the exhaust gas bypass line 20 is connected in parallel to the exhaust gas bypass line 18 and exclusively bypasses the particle filter 14.

Fig. 4 shows a further development of the embodiment of Fig. 2, wherein in the embodiment of Fig. 4 via a charge air bypass line 22 charge air from compressor 13, namely in Fig. 4stromabwärts of the compressor 13 and upstream of the internal combustion engine 10, the exhaust gas bypass line 4, upstream of the reducing agent metering device 16 and upstream of the hydrolysis catalytic converter 17. The charge air flow through this charge air bypass line 22 is adjustable via an adjusting device 23. As a result of this admixing of charge air into the exhaust gas conducted past the exhaust gas bypass line 18 on the particle filter 14, the temperature of the exhaust gas routed via the exhaust gas bypass line 18 can be set precisely to a desired level. As a result, a further increase in efficiency in the area of the SCR catalytic converter 15 and thus the exhaust gas purification is possible. In addition, you get the option that the charge air can be used as dosing air.

Fig. 5 shows an embodiment of the invention, which combines the features of the embodiments of FIGS. 3 and 4 with each other, in which therefore both the further exhaust gas bypass line 20 and the charge air bypass line 22 with the respective adjusting devices 21, 23 is present. Such a combination is particularly preferred for increasing the efficiency of the SCR catalytic converter 15, wherein it should be noted that such a combinatorial use of the further exhaust gas bypass line 20 and the charge air bypass line 22 can also be used in the exemplary embodiment of FIG. 1, in which the bypass line 18, in which the reducing agent metering device 16 and the hydrolysis catalytic converter 17 are positioned, exclusively the particle filter 14 and not the turbine 12 of the exhaust gas turbocharger 11 bypasses.

Fig. 6 shows an embodiment in which it is a development of the internal combustion engine 10 of FIG. 1, wherein the charge air bypass line 22 is provided with the corresponding adjusting device 23 to supply charge air of the exhaust gas bypass line 18 upstream of the Reduktionsmitteldosiereinrichtung 16. In contrast to the exemplary embodiments of FIGS. 4 and 5, the charge air is conducted upstream of the compressor 13 of the exhaust gas turbocharger 11 and not downstream of the compressor 13 of the exhaust gas turbocharger 11 via the charge air bypass line 22 in the direction of the exhaust gas bypass line 18, as in the exemplary embodiments of FIGS. 4 and 5 , In order to facilitate a simplified supply of the charge air into the exhaust gas bypass line 18, however, the variant of FIGS. 4 and 5, in which the charge air is branched off downstream of the compressor 13, is preferred.

FIGS. 1 to 6 have in common that the respective internal combustion engine has a single-stage exhaust gas turbocharging. In contrast, FIGS. 7 to 10 show exemplary embodiments of internal combustion engines having a multistage, namely two-stage, exhaust gas turbocharger, with a further exhaust gas turbocharger 24 having a turbine 25 and a compressor 26 being present in addition to the exhaust gas turbocharger 11.

In the turbine 12 of the exhaust gas turbocharger 11 is then a high-pressure turbine and the turbine 25 of the exhaust gas turbocharger 24 to a low-pressure turbine. Accordingly, the compressor 13 of the exhaust gas turbocharger 11 is a high-pressure compressor and the compressor 26 of the exhaust gas turbocharger 24 is a low-pressure compressor.

In the embodiments of FIGS. 7 to 9, the particulate filter 14 and the SCR catalyst 15 are respectively positioned between the two turbines 12 and 25 of the two exhaust gas turbochargers 11 and 24, again such that the SCR catalyst 15 downstream of the particulate filter 14 is positioned.

In the internal combustion engine 10 of FIG. 7, the exhaust gas bypass line 18, in which the reducing agent metering device 16 and the hydrolysis catalytic converter 17 are positioned, exclusively bypasses the particle filter 14.

8 bypasses the exhaust gas bypass line 18, in which the reducing agent metering device 16 and the hydrolysis catalytic converter 17 are positioned, both the particle filter 14 and the turbine 12 of the exhaust gas turbocharger 11 serving as a high-pressure turbine. FIG. 8 shows the exhaust gas bypass line 18 via the charge air bypass line 22, which branches off downstream of the compressor 13 operating as a high-pressure compressor of the exhaust gas turbocharger 11, in accordance with the embodiments of FIGS. 4 and 5Ladeluft for temperature control of the guided over the exhaust gas bypass line 18 exhaust gas in the same einbringbar.

In the embodiment of FIG. 9, which shows a development of the embodiment of FIG. 8, the further exhaust gas bypass line 20 is additionally present, via the exhaust gas both at the high-pressure turbine 12 and the particle filter 14 and at the Reduktionsmitteldosiereinrichtung 16 and the hydrolysis 17 can be passed over in the direction of the SCR catalyst 15.

Of course, the charge air bypass line 22 according to FIGS. 8 and 9 could also branch off between or in front of the compressors.

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

Common to all embodiments is that via an exhaust gas bypass line 18 exhaust gas can be passed to the particulate filter 14 to pass the exhaust gas passed to the particulate filter 14 via a Reduktionsmitteldosiereinrichtung 16 and a hydrolysis 17 and then forward the SCR catalyst 15. As a result, the effectiveness of the exhaust gas purification can be increased. On the one hand, a blocking of the exhaust gas particulate filter 14 is avoided, on the other hand, an effective implementation of the reducing agent for the SCR exhaust gas purification in the SCR catalyst 15 can be ensured.

A complete decomposition of the liquid reducing agent in the gaseous products in a bypass with optimal conditions for this purpose and the subsequent subsequent return to the SCR catalyst reduces the risk of deposit formation on the SCR catalyst in connection with a heavy oil operation. This means that the minimum operating temperature for the SCR catalyst may decrease with sulfur-containing fuels and that the temperature window for SCR operation may increase.

LIST OF REFERENCE NUMBERS

[0029] <Tb> 10 <sep> engine <Tb> 11 <sep> turbocharger <Tb> 12 <sep> Turbine <Tb> 13 <sep> compressor <Tb> 14 <sep> particle <Tb> 15 <sep> SCR catalyst <Tb> 16 <sep> Reduktionsmitteldosiereinrichtung <Tb> 17 <sep> hydrolysis catalyst <Tb> 18 <sep> exhaust bypass line <Tb> 19 <sep> adjustment <Tb> 20 <sep> exhaust bypass line <Tb> 21 <sep> adjusting device <Tb> 22 <sep> charge air bypass line <Tb> 23 <sep> adjustment <Tb> 24 <sep> turbocharger <Tb> 25 <sep> Turbine <Tb> 26 <sep> compressor

Claims (6)

1. internal combustion engine, in particular with heavy oil operated marine diesel engine, with at least one exhaust 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 Reduktionsmitteldosiereinrichtung (16) in a Abgasbypassleitung (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 Abgasbypassleitung (18), in which the Reduktionsmitteldosiereinrichtung (16 ) and the hydrolysis catalytic converter (17) are positioned, at least around the particle filter (14), so that exhaust gas can be conducted via the exhaust gas bypass line (18) at least bypassing the particle filter (14) in the direction of the SCR catalytic converter (15). 2. Internal combustion engine according to claim 1, characterized in that the exhaust gas bypass line (18), in which the Reduktionsmitteldosiereinrichtung (16) and the hydrolysis (17) are positioned both to the particulate filter (14) and to a turbine (12) of an exhaust gas turbocharger is guided around so that via the exhaust gas bypass line (18) exhaust gas, bypassing the turbine (12) of the respective exhaust gas turbocharger and the particulate filter (14) in the direction of the SCR catalyst (15) can be conducted. 3. Internal combustion engine according to claim 1 or 2, characterized by a further exhaust gas bypass line (20), via the exhaust gas on the one hand, bypassing the particulate filter (14) and on the other hand, bypassing the Reduktionsmitteldosiereinrichtung (16) and the hydrolysis (17) in the direction of the SCR Catalyst is conductive, wherein the exhaust gas flow through the further exhaust gas bypass line via a further adjusting device (21) is adjustable. 4. 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 Reduktionsmitteldosiereinrichtung (16) and the hydrolysis (17 are upstream, the upstream of the Reduktionsmitteldosiereinrichtung (16) and the hydrolysis (17), wherein the charge air flow through the charge air bypass line (22) via an adjusting device (23) is adjustable. 5. Internal combustion engine according to one of claims 1 to 4, characterized by a multi-stage turbocharging, 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 connected. An internal combustion engine according to claim 5, characterized in that the exhaust bypass passage (18) in which the reducing agent metering means (16) and the hydrolysis catalyst (17) are positioned around the particulate filter (14) and the high-pressure turbine (17) positioned upstream of the particulate filter is guided.