EP2751399B1

EP2751399B1 - Arrangement for treating exhaust gases of an internal combustion engine and a corresponding internal combustion engine

Info

Publication number: EP2751399B1
Application number: EP12759785.4A
Authority: EP
Inventors: Klaus Widjeskog
Original assignee: Wartsila Finland Oy
Current assignee: Wartsila Finland Oy
Priority date: 2011-08-29
Filing date: 2012-06-18
Publication date: 2015-12-09
Anticipated expiration: 2032-06-18
Also published as: FI20115836L; FI20115836A0; WO2013030433A2; EP2751399A2; KR101891857B1; FI125443B; KR20140074318A; WO2013030433A3; CN103797223B; CN103797223A

Description

Technical field

Invention relates to an arrangement for treating exhaust gases of an internal combustion piston engine comprising a gas treatment apparatus inside of which a space is formed, at least two exhaust gas inlets and at least one exhaust gas outlet opening into the space, and an exhaust gas treatment unit arranged into the space.
Invention relates also to an internal combustion piston engine provided with an arrangement for treating exhaust gases.

Background art

Exhaust gas emission requirements of internal combustion piston engines become more and more stringent. In order to cope with such requirements there are various techniques available by means of which the gaseous emissions may be controlled when the engine is running. On the other hand, it is not desirable that the overall performance of the engine will suffer resulted from actions aiming to reduce the emissions.
Especially catalysts are commonly used to speed up reactions of certain substances contained by the exhaust gases of internal combustion piston engines. Such substances are for example nitrogen oxides, hydrocarbons such as methane, carbon oxides etc.
DE 10 2008061222A1 describes an internal combustion piston engine having two or more banks of cylinders, each containing one exhaust gas line and a charge air line. According to the document there is a common emission control device, particularly a catalyst arranged in connection with the engine. The emission control device is integrated into the engine architecture in order to reduce space requirements of the system.
US 3247666 describes a manifold afterburner device for exhaust emissions control in an internal combustion engine system inside of which a space is formed, and at least two exhaust gas inlets and at least one exhaust gas outlet opening into the space inside the gas treatment apparatus. There is also an exhaust gas treatment unit arranged into the space, which exhaust gas treatment unit is arranged to border two partial spaces into the space and is provided with flow passages allowing gas to flow through the treatment unit,
WO 93/18285 discloses a two stroke internal combustion engine exhaust line wherein the exhaust line has two selectable parallel routes for the exhaust gas to flow. One of the routes is provided with a catalyst whereas the other route is not provided with a catalyst.
When utilizing a catalytic emission reduction system in connection with internal combustion piston engines there are several issues to consider. Firstly, the location of the system in the exhaust gas stream more or less defines the available temperature range in which the catalyst is to operate. Typically such a catalyst should be located next to turbine section(s) of the engine i.e. quite near to the engine. Secondly, a risk of fouling and clogging is always an issue to consider, particularly in connection with engines operating with e.g. heavy fuel oil, although soot formation may take place with gas operated engines, too. Thirdly, the space requirements set of a catalytic emission reduction system are typically considerable. The general aim is to spend as little space as possible. It is an object of the invention to provide an arrangement for treating exhaust gases of an internal combustion piston engine and an internal combustion piston engine, which solves at least one of the above mentioned problems of prior art.

Disclosure of the Invention

Objects of the invention are substantially met by an arrangement for treating exhaust gases of an internal combustion piston engine comprising a gas treatment apparatus inside of which a space is formed, at least two exhaust gas inlets and at least one exhaust gas outlet opening into the space, and an exhaust gas treatment unit arranged into the space. The exhaust gas treatment unit is arranged to border two partial spaces into the space, which gas treatment unit is provided with flow passages allowing gas to flow through the treatment unit. It is characteristic to the invention that the flow passages comprise a catalyst section and one of the at least two exhaust gas inlets opens into the first partial space and the other one of the at least two exhaust gas inlets opens into the second partial space and that the at least one exhaust gas outlet is in flow communication with both of the partial spaces.
This provides an arrangement which simultaneously performs effective gas treatment without risking the operational reliability. This also makes use of the pulsating exhaust gas flow coming from the cylinders of the engine. This also reduces noise and vibration related problems of the engine.
According to an embodiment of the invention the least two exhaust gas inlets are directed or otherwise arranged so that the velocity of the exhaust gas has a direction partially towards the exhaust gas treatment unit.
This provides an operational effect of making the gas at least partly hitting the exhaust gas treatment unit and flowing through it. Thus the treatment of the gas in the treatment unit is based on the flow-through of the gas due to pulsation gas flow in the space. Thus even if the exhaust gas treatment unit of parts of it would be clogged that does not have practically any affect on the operation of the engine. Due to the construction and pulsating exhaust gas flow the arrangement is also more resistant against soot and clogging.
Placing the exhaust gas treatment unit as described above minimizes also the need of external piping and bypass valves.
According to another embodiment of the invention the gas treatment apparatus is an elongated manifold having a longitudinal axis and the exhaust gas treatment unit is a wall-like structure arranged to extend in the manifold in the direction of the longitudinal axis.
According to still another embodiment of the invention the wall-like structure is undulating in the in the direction of the longitudinal axis. The wall-like structure also may be for example zigzag formed in the in the direction of the longitudinal axis.
The exhaust gas treatment unit borders two partial spaces at least at the location where the at least two exhaust gas inlets open into either of the partial space.
According to an embodiment of the invention the exhaust gas treatment unit comprises gas flow passages extending between the two partial spaces which passages are at least partially provided with catalyst in its surface. Such a surface is called also as catalyst surface in this context. Preferably the catalyst is partial oxidation catalyst catalyzing the oxidation reaction of any residual hydrocarbon in the exhaust gas.
According to an embodiment of the invention the catalyst surface is arranged in the middle section of the passages.
Preferably the gas treatment apparatus is an exhaust gas manifold of the engine.
According to an embodiment of the invention the exhaust gas manifold is formed of several gas treatment apparatuses arranged successively to each other.
The wall-like structure of the exhaust gas treatment unit extends in cross direction of the treatment apparatus between two inner surfaces thereof.
An internal combustion piston engine according to the invention is provided with an arrangement for treating exhaust gases comprising a gas treatment apparatus inside of which a space is formed, at least two exhaust gas inlets and at least one exhaust gas outlet opening into the space, and an exhaust gas treatment unit arranged into the space. It is characteristic to the internal combustion engine that the exhaust gas treatment unit is arranged to border two partial spaces into the space, which gas treatment unit is provided with flow passages allowing gas to flow through the treatment unit which flow passages comprise a catalyst section. Additionally one of the at least two exhaust gas inlets opens into the first partial space and the other one of the at least two exhaust gas inlets opens into the second partial space and the at least one exhaust gas outlet is in flow communication with both of the partial spaces.
According to an embodiment of the invention the engine is a V-engine and an arrangement for treating exhaust gases is arranged the between the banks of the engine.
According to another embodiment of the invention the engine is an in-line engine.

Brief Description of Drawings

In the following, the invention will be described with reference to the accompanying exemplary, schematic drawings, in which

Figure 1 illustrates an internal combustion piston engine according to an embodiment of the invention,
Figure 2 illustrates a section II-II of Figure 1,
Figure 3 illustrates a partial view of an internal combustion piston engine according to another embodiment of the invention,
Figure 4 illustrates a partial view of an internal combustion piston engine according to still another embodiment of the invention,
Figure 5 illustrates a partial view of an internal combustion piston engine according to still another embodiment of the invention,
Figure 6 illustrates a partial view of an internal combustion piston engine according to another embodiment of the invention,
Figure 7 illustrates an internal combustion piston engine according to another embodiment of the invention,
Figure 8 illustrates an internal combustion piston engine according to still another embodiment of the invention, and
Figure 9 illustrates an internal combustion piston engine according to still another embodiment of the invention.

Detailed Description of Drawings

Figure 1 depicts schematically an internal combustion piston engine 10, more specifically an internal combustion piston engine, which is called simply as an engine in the following. In Figure 2 there is shown the section II-II of the Figure 1 and respectively Figure 1 shows the section I-I of the Figure 2. In the following the invention and embodiments relating to the invention are described with the reference to Figures 1 and 2. The engine comprises a body 12 or a block into which various parts of the engine known as such have been assembled. In figure 1 there is shown cylinder heads 14 arranged as two parallel inclined banks i.e. in this case the engine is so called V-engine. Each cylinder of the engine is in connection with an exhaust gas manifold 16 by an exhaust gas conduit 18, which connects one cylinder head to the exhaust gas manifold 16 common to all the cylinders of the engine. Each exhaust gas conduit 18 comprises an exhaust gas inlet 20 which opens into the space 22 formed into the exhaust gas manifold 16. The exhaust gas manifold 16 comprises also an exhaust gas outlet 24 arranged to open into the space 22.
Additionally the exhaust gas manifold 16 is provided with an exhaust gas treatment unit 26 arranged into the space 22 formed in the exhaust gas manifold. By means of the treatment unit exhaust gas may be treated in order to reduce emissions admitted to the surrounding air by the engine when operating. Thus the exhaust gas manifold is or operates also a gas treatment apparatus. The gas treatment unit 26 is provided with flow passages 26' allowing gas to flow through the treatment unit. In the embodiment of Figures 1 and 2 the exhaust gas treatment unit 26 in the exhaust gas manifold 16 is vertically orientated and the inlets 20 are horizontally both sides of the exhaust gas treatment unit 26.
The gas treatment apparatus is described in the Figures 1 and 1 in connection with a V-engine. The gas treatment apparatus is arranged between the banks of the engine and the exhaust gas inlets 20 are arranged to both sides of the gas treatment apparatus. In the V engine the location between cylinder banks on top of engine is advantageous when considering gravitation point of view, heat radiation, vibration and noise spreading to the surroundings.
The exhaust gas treatment unit 26 is arranged to border two partial spaces 22.1, 22.2 into the space 22. Thus the exhaust gas treatment unit 26 extends in cross direction of the treatment apparatus between two inner surfaces of the gas treatment apparatus. The gas treatment apparatus is an elongated manifold having a longitudinal axis A. The exhaust gas treatment unit is a wall-like structure arranged to extend in the manifold so that the partial spaces are substantially identical to each other. The exhaust gas inlets 20 are arranged so that a part of the exhaust gas inlets open into the first partial space 22.1 and another part of the exhaust gas inlets open in to the second partial space 22.2. In other words, when the engine comprises at least two exhaust gas inlets opening into the space, one of the at least two exhaust gas inlets opens into the first partial space 22.1 and the other one of the at least two exhaust gas inlets opens into the second partial space 22.2. Thus exhaust gas inlets successive in the direction of the longitudinal axis A open into different partial spaces. The exhaust gas outlet is in flow communication with both of the first and the second partial spaces. The cross section of the exhaust gas treatment apparatus and the partial spaces may be circular, rectangular or of other shape according to the need.
When the engine is operating the exhaust gas will hit the treatment unit from both sides when it is arranged as shown in the figure 1 and 2. The exhaust gas treatment unit 26 acts also as a mere pulsation dampener.
According to an embodiment of the invention the exhaust gas treatment unit 26 comprises multiple parallel gas flow passages 26' extending between the two partial spaces 22.1, 22.2 which passages are at least partially provided with catalyst surface. According to a further embodiment of the invention the gas flow passages 26' are arranged in separate catalyst units arranged to the gas treatment unit 26. The several catalyst units arranged into a frame (not shown) of the exhaust gas treatment unit 26. Preferably each catalyst unit is arranged to have equal characteristics for gas flowing in either direction through the passages. In the Figures 1 and 2 an embodiment of invention is shown according to which the catalyst units extend from the first end of the treatment unit 26 to its second end. The flow passages of the catalyst units are arranged perpendicular to the longitudinal axis A of the treatment apparatus (16). The shape and direction or the passages may vary. In figure 3 there is shown an embodiment in which the passages are V-shaped to direct the through flowing gas at least partially backwards.
Figure 2 shows by the arrows how the pulsating exhaust gas flow will hit through the exhaust gas treatment units and also hit back to starting side. Due to the back and forth flow of gas through catalyst units from both directions, thus the passages 26' will stay free from any substantial soot accumulations maintaining low risk of clogging. Soot is not necessarily needed to pass through the catalyst unit and thus the catalyst unit may be provided with substantially dense grid of flow channels having bigger specific catalyst area. The catalyst unit reacts as pulse dampener at same time.
Additionally, the present invention provides a operational safeguard against unlikely happening clogging of the catalyst unit. Should the catalyst unit be clogged, the gas will still flow forward in the partial space.
Each exhaust gas conduit 18 from cylinders may be angled to have a suitable angle that will cause desired flow pattern and behavior of the gas when entering into the partial spaces 22.1, 22.2. It is also possible to set the firing sequence of the engine such that the pulses will hit back and forth through the element. With pulsating exhaust gas flow in the arrangement according to the invention the exhaust pulses may flow through element more than once. The exhaust gas conduit 18 is according to an embodiment of the invention an integral part of the gas treatment apparatus 16. According to another embodiment the exhaust gas conduit 18 is removably fixed to the gas treatment apparatus 16.
In Figure 2 there is also shown an embodiment of the invention in which a fluid inlet system 28 is arranged to the exhaust gas treatment unit 26. The fluid inlet system is provided with individual outlets over the whole length of the exhaust gas treatment unit. It is arranged to run inside the treatment unit as integrated system. The fluid inlet system may be for example a water inlet system introducing controlled amount of water by means of which the exhaust gas treatment unit 26, particularly the catalyst units are maintained within desired temperature window.
According to another embodiment of the invention the fluid inlet system is utilized for introducing reducing agent, such as urea, into the gas stream to utilize catalytic reactions in the catalyst units 26.
Figure 4 depicts an embodiment of the invention in which a rectangular catalyst unit 26 is coated with catalytic material only in the middle section 26.1 forming the catalyst section. The outer areas 26.2 are arranged for damping purposes. Figure 4 also shows an impingement plate 20' or alike against which the strongest gas flow pulse may hit. It is arranged at least partly in front of the inlet 20.The impingement plate may be a grid plate or a hole plate.
Figures 5 and 6 depict different general layouts of the exhaust gas treatment unit 26. In Figure 5 the wall-like structure is undulating in the direction of the longitudinal axis and in Figure 6 the wall-like structure is zigzag formed in the in the direction of the longitudinal axis.
In the Figure 7 there is shown a modification of the embodiment of Figure 2 in which the arrangement for treating exhaust gases of an internal combustion piston engine comprises several gas treatment apparatuses 16 arranged successively to each other. The gas treatment apparatus 16 in the Figure 7 are joined with each other by a flange attachment whereas they together form the exhaust gas manifold of the engine. Each gas treatment apparatus 16 in the embodiment of the Figure 7 has a space 22, and at least two exhaust gas inlets 20 and at least one exhaust gas outlet 24 opening into the space 22 and an exhaust gas treatment unit 26 arranged into the space 22, which exhaust gas treatment unit 26 is arranged to border two partial spaces 22.1, 22.2 into the space 22. Also one of the at least two exhaust gas inlets 20 opens into the first partial space 22.1 and the other one of the at least two exhaust gas inlets opens into the second partial space 22.2.
Figure 8 depicts schematically an internal combustion piston engine 10', which is an in-line engine. In the embodiment of Figure 8 the exhaust gas treatment unit 26 in the exhaust gas manifold 16 is horizontally orientated and the inlets 20 are vertically both sides of the exhaust gas treatment unit 26.
Figure 9 depicts schematically an internal combustion piston engine 10', which is also an in-line engine. In the embodiment of Figure 9 the exhaust gas treatment unit 26 in the exhaust gas manifold 16 is substantially vertically orientated and part of the inlets 20 are led through the exhaust gas treatment unit 26 to open into the other partial space 22.2.
While the invention has been described herein by way of examples in connection with what are, at present, considered to be the most preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various combinations or modifications of its features, and several other applications included within the scope of the invention, as defined in the appended claims. The details mentioned in connection with any embodiment above may be used in connection with another embodiment when such a combination is technically feasible.

Claims

Arrangement for treating exhaust gases of an internal combustion piston engine (10, 10') comprising a gas treatment apparatus (16) inside of which a space (22) is formed, and at least two exhaust gas inlets (20) and at least one exhaust gas outlet (24) opening into the space (22) inside the gas treatment apparatus, and an exhaust gas treatment unit (26) arranged inside the space (22), which exhaust gas treatment unit (26) is arranged to border two partial spaces (22.1, 22.2) inside the space (22), and the gas treatment unit is provided with flow passages (26') allowing gas to flow through the treatment unit, characterized in that the exhaust gas treatment unit (26) comprises gas flow passages (26') extending between the two partial spaces (22.1,22.2), and the flow passages (26') comprise a catalyst section (26.1), and that one of the at least two exhaust gas inlets (20) opens into the first partial space (22.1) and the other one of the at least two exhaust gas inlets opens into the second partial space (22.2) and that the at least one exhaust gas outlet is in flow communication with both of the partial spaces.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 1, characterized in that the gas treatment apparatus is an elongated manifold having a longitudinal axis (A) and that the exhaust gas treatment unit (26) is a wall-like structure arranged to extend in the manifold in the direction of the longitudinal axis (A).
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 2, characterized in that the wall-like structure is undulating in the direction of the longitudinal axis.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 2, characterized in that the wall-like structure is zigzag formed in the direction of the longitudinal axis.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 1, characterized in that the exhaust gas treatment unit (26) borders two partial spaces (22.1, 22.2) at least at the location where the at least two exhaust gas inlets open into either of the partial space.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 1, characterized in that the passages are at least partially provided with catalyst in their surface.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 6, characterized in that the catalyst is partial oxidation catalyst.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 6, characterized in that the catalyst is arranged in the middle section (26.1) of the passages.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 1, characterized in that the gas treatment apparatus (16) is an exhaust gas manifold.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 9, characterized in that the exhaust gas manifold is formed of several gas treatment apparatuses (16) arranged successively to each other.
Arrangement for treating exhaust gases of an internal combustion piston engine (10) according the claim 9, characterized in that the wall-like structure of the exhaust gas treatment unit (26) extends in cross direction of the treatment apparatus between two inner surfaces thereof.
An internal combustion piston engine (10) provided with an arrangement for treating exhaust gases according to anyone of the preceding claims.
An internal combustion piston engine according to claim 12, characterized in that the engine is a V- engine and that an arrangement for treating exhaust gases is arranged between the banks of the engine.
An internal combustion piston engine according to claim 12, characterized in that the engine is an in-line engine (10').