DE102017203267A1 - Internal combustion engine with an exhaust system - Google Patents

Abstract

Internal combustion engine with an exhaust system, for discharging exhaust gas of the internal combustion engine, wherein a particulate filter is arranged in the exhaust system and wherein a secondary air inlet opening is provided for introducing secondary air via a closure element in the exhaust system, wherein the secondary air inlet opening in the flow direction of the exhaust gas to the particulate filter in the exhaust system is arranged.
The inventive design of the particulate filter is spared by the high exotherms, while reducing carbon monoxide emissions.

Description

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

For technical environment is for example on the German disclosure DE 10 2012 021 573 A1 pointed. From this publication, a method for operating a burner and an exhaust system with a burner operable in this way are known. The invention relates to a method for operating an air-fueled and combustible burner of an exhaust system, the burner exhaust gas of which is combined with an internal combustion engine exhaust gas in the spark-ignition internal combustion engine and a mixed exhaust gas thus obtained is fed to at least one catalytic converter having a three-way catalytic function, wherein an actual exhaust gas is present. Oxygen content (lambda-is) of the mixed exhaust gas or a correlated therewith size is measured and an amount of fuel supplied to the burner (m _k ) is influenced so that the actual oxygen content (lambda) is a desired oxygen content (lambda-soll) of the mixed exhaust gas at least approaches.

Next is from the German patent application DE 10 2010 044 102 A1 , from which the present invention proceeds, an exhaust system for an internal combustion engine with a particulate filter known. In this publication, an exhaust system for an internal combustion engine is described, which has an exhaust line, which is connectable to an outlet side of the internal combustion engine, wherein in the exhaust line in the downstream direction arranged at least one catalyst and this is followed by a particle filter. Further, the exhaust line upstream of the particulate filter, a secondary air inlet opening for introducing secondary air via at least one valve is provided in the exhaust line, wherein the secondary air is compressed air.

The documents known from the prior art carry the secondary air in front of the Otto particle filter ( DE 10 2010 044 102 A1 ) or in front of the catalyst ( DE 10 2012 021 573 A1 ), wherein typically the gasoline particulate filter is located downstream of the catalyst in the exhaust gas flow direction. These existing arrangements have the disadvantage that the high exotherm can lead to an Ottopartikelfiltergeschaden or catalyst damage, or the life of the emission-relevant components are shortened. The released high exotherm (thermal energy) comes about through the oxidation of the carbon monoxide directly in the exhaust gas, by the oxidation of the carbon monoxide on a catalytically coated surface or by the oxidation of soot in the Ottopartikelfilter.

Object of the present invention is to show a measure to avoid the above-mentioned disadvantages.

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

The advantage of the present invention is that the secondary air injection downstream of the particle filter leaves the particle filter and any catalyst arranged upstream of the particle filter from the high exotherm, while reducing carbon monoxide emissions. The arrangement according to the invention is suitable for both gasoline and diesel combustion.

Due to the configuration according to claim 2, the arrangement according to the invention can also be used for internal combustion engines with a turbocharger.

The embodiment according to claim 3 is a preferred embodiment, in which there is sufficient air for the secondary air introduction in each operating state of the internal combustion engine.

The embodiment according to claim 4 is a second preferred embodiment, in which an electric compressor is used to convey the air, but which must always be switchable as needed.

With the embodiment according to claim 5 an increase in efficiency in the reduction of carbon monoxide is possible.

The embodiments according to the claims 6 to 9 are preferred embodiments for different configurations of emission control systems for both gasoline and diesel combustion.

• 1 zeigt einen schematischen Aufbau einer erfindungsgemäßen Brennkraftmaschine mit einer Abgasanlage.
• 2 zeigt schematisch eine erste Ausführungsvariante.
• 3 zeigt schematisch eine zweite Ausführungsvariante.
• 4 zeigt schematisch eine dritte Ausführungsvariante.
• 5 zeigt schematisch eine vierte Ausführungsvariante.
• 6 zeigt schematisch eine fünfte Ausführungsvariante.
• 7 zeigt schematisch eine sechste Ausführungsvariante.
• 8 zeigt schematisch eine siebte Ausführungsvariante.
• 9 zeigt schematisch eine achte Ausführungsvariante.
• 10 zeigt schematisch eine neunte Ausführungsvariante.
• 11 zeigt schematisch eine zehnte Ausführungsvariante.
• 12 zeigt schematisch eine elfte Ausführungsvariante.
• 13 zeigt schematisch eine zwölfte Ausführungsvariante.

The invention is described in more detail below with reference to a schematic structure of the overall system and to twelve further variants in thirteen figures.

• 1 shows a schematic structure of an internal combustion engine according to the invention with an exhaust system.
• 2 schematically shows a first embodiment.
• 3 schematically shows a second embodiment.
• 4 schematically shows a third embodiment.
• 5 schematically shows a fourth embodiment.
• 6 schematically shows a fifth embodiment.
• 7 schematically shows a sixth embodiment.
• 8th schematically shows a seventh embodiment.
• 9 schematically shows an eighth embodiment.
• 10 schematically shows a ninth embodiment variant.
• 11 schematically shows a tenth embodiment variant.
• 12 shows schematically an eleventh embodiment.
• 13 schematically shows a twelfth embodiment.

The following apply in the figures 1 to 13 for same components the same reference numbers.

1 shows a schematic structure of an internal combustion engine according to the invention 1 with an exhaust system 2 , The exhaust system 2 serves for discharging exhaust gas of the internal combustion engine 1 , being in the exhaust system 2 a particle filter 3 is arranged. Next is in the exhaust system 2 a secondary air inlet opening 4 provided for introducing secondary air via a closure element 5 in the exhaust system 2 , The closure element 5 may be for example a valve or a flap. According to the invention, the secondary air inlet opening 4 in the flow direction of the exhaust gas after the particle filter 3 in the exhaust system 2 arranged.

A flow direction of the exhaust gas is in the exhaust system 2 represented by small arrows. A flow direction of the secondary air is also indicated by a small arrow in the area of the secondary air inlet opening 4 shown.

In this embodiment above, it is an internal combustion engine with suction engine operation.

In a first embodiment of the 1 can the secondary air inlet 4 with the fresh air line 8th between the compressor 7 and the internal combustion engine 1 via a secondary air line 9 with a closure element 5 , such as a valve or a flap, be air-conducting connectable.

In a further, not shown embodiment, the secondary air inlet opening 4 also be connected to an electric compressor via a secondary air line air-conducting.

According to the invention, however, this arrangement can also, as in 1 is shown, are used for an internal combustion engine with an exhaust gas turbocharger. In this case, the internal combustion engine 1 an exhaust gas turbocharger with a turbine 6 and a compressor 7 on, with the turbine 6 in the exhaust system 2 between the internal combustion engine 1 and the particulate filter 3 and the compressor 7 in a fresh air line 8th the internal combustion engine 1 is arranged.

Input side in the fresh air line 8th , is a direction of flow of fresh air is shown by an arrow. In the flow direction of the fresh air is in the fresh air line 8th first an air filter 16 arranged, then the compressor 7 , continue with a charge air cooler 16 and a throttle 18 , Moreover, in the embodiment in FIG 1 between the turbine 6 and the particulate filter 3 , which is preferably a gasoline particulate filter, but may also be a diesel particulate filter, a first catalyst 10 intended. Next is in the exhaust system 2 after the secondary air inlet opening 4 in the exhaust system 2 a silencer 19 arranged.

In the following 2 to 13 twelve further variants of the internal combustion engine according to the invention are shown. In each figure are the exhaust system 2 in the flow direction of the exhaust gas after the turbine 6 and the secondary air line 9 in the direction of flow of the secondary air after the closure element 5 shown as a detail enlargement.

2 shows a first embodiment, wherein in the flow direction of the exhaust gas behind the particulate filter 3 at least two secondary air inlet openings 4 in the present embodiment four, in the exhaust system 2 are provided. By this measure, the reduction of carbon monoxide is much more efficient. Next is in 2 in the flow direction of the exhaust gas behind the secondary air inlet openings 4 a silencer 19 arranged.

3 shows a second embodiment, in which between the internal combustion engine 1 and the particulate filter 3 the first catalyst 10 in the exhaust system 2 is arranged. In this second embodiment, the first catalyst 10 a three-way catalyst 11 , Next is in the flow direction of the exhaust gas to the secondary air inlet opening 4 in the exhaust system 2 a silencer 19 arranged.

4 shows a third embodiment, wherein in the flow direction of the exhaust gas behind the secondary air inlet opening 4 a second catalyst 14 in the exhaust system 2 is arranged.

5 shows a fourth embodiment in the direction of flow of the exhaust gas behind the secondary air inlet opening 4 a second catalyst 14 is provided and the first catalyst 10 has been omitted.

6 shows a fifth embodiment in which the first catalyst 10 is a NO _x storage catalyst 12 and the second catalyst 14 has been omitted.

7 shows a sixth embodiment in which the first catalyst 10 is a NO _x storage catalyst and the second catalyst 14 in the flow direction of the exhaust gas behind the secondary air inlet opening 4 is arranged.

8th shows a seventh embodiment in the first catalyst 10 a heatable catalyst 13 is and in the flow direction of the exhaust gas to the secondary air inlet opening 4 a second catalyst 14 in the exhaust system 2 is provided.

9 shows an eighth embodiment in which the first catalyst 10 is omitted and the second catalyst 14 a heatable catalyst 13 is.

10 shows a ninth embodiment in which the first catalyst 10, a three-way catalyst 11 and the second catalyst 14 a heatable catalyst 13 is.

11 Fig. 10 shows a tenth embodiment in which the first catalyst 10 is a three-way catalyst 11 is, wherein between the first catalyst 10 and the particulate filter 3 a NO _x storage catalyst 12 in the exhaust system 2 is provided. The second catalyst 14 is omitted in this embodiment.

12 shows an eleventh embodiment according to 11 , In this embodiment, the second catalyst 14 is provided.

13 shows a twelfth embodiment in which the first catalyst 10, a three-way catalyst 11 is and the second catalyst 14 an SCR catalyst 15 is.

In other words, with respect to the prior art and the invention:

The invention relates to an internal combustion engine 1 to reduce particulate emissions a particulate filter 3 in the exhaust system 2 having.

It is state of the art that particle filters 3 for reducing the particle emissions of an internal combustion engine 1 be used. Furthermore, it is known the particle filter 3 , In particular, a gasoline particulate filter or a diesel particulate filter, with a catalytic coating for reducing the exhaust emissions from an internal combustion engine 1 to coat or a particle filter 3 with a three-way catalyst 11 to combine.

The catalytic coating of the particulate filter 3 or the first and / or the second catalyst 10 . 14 can only fulfill its function from a light-off temperature dependent on the aging state of the coating. Below the light-off temperature, the catalytic ability of the coating is extremely low. In order to keep the exhaust emissions low until the coating starts, it is still state of the art, in front of the coated particle filter 3 or in front of the catalysts 10 . 14 Supply secondary air and the internal combustion engine 1 operate simultaneously at a low air fuel ratio (rich lambda). In the rich lambda range, more carbon monoxide and unburned hydrocarbons are produced. These oxidize in conjunction with the oxygen contained in the secondary air. This is an exothermic reaction, whose energy in the form of heat for heating the catalysts 10 . 14 is being used. This allows the time to reach the light-off temperature of the catalysts 10 . 14 be significantly reduced. With increasing load that of the internal combustion engine 1 is demanded, also increases the exhaust gas temperature. To components of the internal combustion engine 1 , such as the particulate filter 3 or to protect the exhaust gas turbocharger from excessive exhaust gas temperatures, it is also known to reduce the exhaust gas temperature by enriching the air-fuel mixture. Due to the rich lambda, the proportion of oxygen in the exhaust gas decreases and the proportion of unburned hydrocarbons and carbon monoxide increases. Due to the lack of oxygen in the exhaust gas, the catalytic coating can not oxidize the unburned hydrocarbons and carbon monoxides. With this fact, the present invention is concerned.

The subject of the present invention is the reduction of emissions by the supply of secondary air into the exhaust gas. According to the invention, the secondary air is fed in the flow direction downstream of the particle filter 3 , Due to the oxygen contained in the secondary air, the carbon monoxide, which are not oxidized due to the rich lambda by means of a three-way coating, after the Ottopartikelfilter 3 oxidized and thus lowered the exhaust emissions of the richly fueled internal combustion engine.

1. 1. Eine Sekundärluftleitung 9 von der Druckseite des Verdichters 7 (frischluftseitig in Strömungsrichtung nach dem Verdichter 7) zur Sekundärluftzuführstelle 4 nach dem Partikelfilter 3. Ein Verschlusselement 5, wie z. B. ein Ventil oder eine Klappe, übernimmt die Steuerung des Sekundärluftmassenstroms und verhindert gleichzeitig ein Zurückströmen von Abgas in den Frischluftstrang 8. Das Zurückströmen eines Abgases in den Frischluftstrang 8 kann in einigen Betriebspunkten der Brennkraftmaschine 1 zur Steigerung der Abgasrückführrate und somit zur Senkung innermotorischer Stickstoffemissionen jedoch erwünscht sein.
2. 2. Förderung von Umgebungsluft durch eine elektrisch betriebene Sekundärluftpumpe und ein Sekundärluftventil. Statt einer elektrischen Sekundärluftpumpe kann auch ein elektrisch angetriebener Verdichter, dessen primäre Funktion die Unterstützung des Abgasturboladers ist, die Sekundärluftversorgung bereitstellen. Auch hier übernimmt ein Verschlusselement 5, wie z. B. ein Ventil oder eine Klappe, die Steuerung des Frischluftmassenstroms und verhindert gleichzeitig ein Zurückströmen von Abgas in den Frischluftstrang 8.
3. 3. Um nach dem Partikelfilter 3 das Material der abgasführenden Leitung vor lokal zu hohen Exothermen zu schützen oder zur Effizienzsteigerung der Reduzierung von Kohlenstoffmonoxid, kann es sinnvoll sein, mehrere statt nur einer Sekundärluftzufuhrstelle 4 nach dem Partikelfilter 3 einzuführen.

Summary of possible versions of the secondary air supply system:

1. 1. A secondary air line 9 from the pressure side of the compressor 7 (Fresh air side in the flow direction after the compressor 7 ) to the secondary air supply point 4 after the particle filter 3 , A closure element 5 , such as As a valve or a flap, takes over the control of the secondary air mass flow and simultaneously prevents backflow of exhaust gas into the fresh air line 8th , The backflow of an exhaust gas into the fresh air line 8th can in some operating points of the internal combustion engine 1 However, to increase the exhaust gas recirculation rate and thus to reduce internal engine nitrogen emissions may be desirable.
2. 2. Promotion of ambient air through an electrically operated secondary air pump and a secondary air valve. Instead of an electric secondary air pump and an electrically driven compressor whose primary function is the support of the exhaust gas turbocharger, provide the secondary air supply. Again, a closure element takes over 5 , such as As a valve or a flap, the control of the fresh air mass flow and simultaneously prevents backflow of exhaust gas into the fresh air line 8th ,
3. 3. To go to the particle filter 3 To protect the material of the exhaust gas line from locally too high exotherms or to increase the efficiency of the reduction of carbon monoxide, it may be useful to have more than one secondary air supply point 4 after the particle filter 3 introduce.

LIST OF REFERENCE NUMBERS

1.

Internal combustion engine

Second

exhaust system

Third

particulate Filter

4th

Secondary air inlet opening

5th

closure element

6th

turbine

7th

compressor

8th.

Fresh air train

9th

Secondary air line

10th

first catalyst

11th

Three-way catalytic converter

12th

NO _x storage catalyst

13th

heatable catalyst

14th

second catalyst

15th

SCR catalyst

16th

air filter

17th

Intercooler

18th

throttle

19th

silencer

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 102012021573 A1 [0002, 0004]
• DE 102010044102 A1 [0003, 0004]

Claims (9)

Internal combustion engine (1) with an exhaust system (2), for discharging exhaust gas of the internal combustion engine (1), wherein in the exhaust system (2) a particulate filter (3) is arranged and wherein a secondary air inlet (4) is provided for introducing secondary air over a Closure element (5) in the exhaust system (2), characterized in that the secondary air inlet opening (4) in the flow direction of the exhaust gas to the particle filter (3) in the exhaust system (2) is arranged. Internal combustion engine with an exhaust system after Claim 1 , characterized in that the internal combustion engine (1) has an exhaust gas turbocharger with a turbine (6) and a compressor (7), wherein the turbine (6) in the exhaust system (2) between the internal combustion engine (1) and the particulate filter (3) and the compressor (7) in a fresh air line (8) of the internal combustion engine (1) is arranged. Internal combustion engine with an exhaust system after Claim 2 , characterized in that the secondary air inlet opening (4) with the fresh air line (8) between the compressor (7) and the internal combustion engine (1) via a secondary air line (9) air leading is connected. Internal combustion engine with an exhaust system after Claim 2 , characterized in that the secondary air inlet opening (4) with an electric compressor via a secondary air line air leader is connectable. Internal combustion engine with an exhaust system according to one of Claims 1 to 4 , characterized in that in the flow direction of the exhaust gas behind the particulate filter (3) at least two secondary air inlet openings (4) in the exhaust system (2) are provided. Internal combustion engine with an exhaust system according to one of Claims 1 to 5 , characterized in that between the internal combustion engine (1) and the particulate filter (3), a first catalyst (10) in the exhaust system (2) is arranged. Internal combustion engine with an exhaust system after Claim 6 , characterized in that the first catalyst (10) is a three-way catalyst (11) or a NO _x storage catalyst (12) or a heatable catalyst (13). Internal combustion engine with an exhaust system after Claim 2 one of the Claims 1 to 7 , characterized in that in the exhaust system (2) in the flow direction of the exhaust gas to the secondary air inlet opening (4), a second catalyst (14) is arranged. Internal combustion engine with an exhaust system after Claim 8 , characterized in that the second catalyst (14) is a SCR catalyst (Selective Catalytic Reduction) (15).

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