JP3510123B2 - Large diesel engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a large diesel engine, and more particularly to a two-cycle large diesel engine having a large number of cylinders. Each of the plurality of cylinders is preferably formed in a tubular shape through at least one exhaust connection pipe, and is connected to an exhaust manifold whose end portion can be closed with a lid, and the exhaust pipe branches from the exhaust manifold to form the exhaust gas. The manifold has a catalytic device,
A gas capable of supplying a reducing agent is recirculated to the catalyst device by a supply device provided upstream of the catalyst device.

[0002]

2. Description of the Prior Art A device of this kind is known from EP 0 468 919. In this known device, the exhaust manifold has a central tube for receiving the catalytic device, the tube being surrounded by an annular space, the exhaust connecting pipe opening towards the annular space, the annular space being Has one end closed and the other end open. Through this open end, the entire exhaust volume flow rate reaches the catalyst device, a diffuser cylinder is provided in front of the catalyst device, and an exhaust pipe leading to the turbine of the exhaust supercharger is branched. The area is provided at the rear.

A disadvantage of this invention is that there is only one flow path for exhaust. That is, the entire exhaust volume flow must flow through the entire length of the catalytic device. Therefore, a relatively large flow cross section is required and the structure is voluminous. Even if one member of the catalyst device is clogged, the only flow path through the catalyst device is blocked in such an invention. In such a case, a bypass pipe must be opened along the catalytic device, so that the entire exhaust volume flow must be fed untreated to the exhaust supercharger. In such cases it is not possible to partially maintain the catalytic action. A further disadvantage of the known device is that the scattering cylinders in front of the catalytic device make the structure of the device too large to be overlooked, which is undesirable. Further, the catalyst device is difficult to reach from the side of the scattering cylinder, which has an unfavorable influence on the ease of installation and maintenance. Therefore, the known device cannot be said to be sufficiently simple, easy, and reliable in operation.

[0004]

For the above reasons, the object of the present invention is to prevent the disadvantages of the known device in a large-sized diesel engine of the kind described above and to improve the operational reliability of the catalyst device. Is to raise.

[0005]

The present invention solves these problems as follows. That is, an exhaust chamber is provided substantially in the center of the exhaust manifold, an exhaust pipe branches from the exhaust chamber, the exhaust chamber divides the catalyst device into two parts, and these parts are divided into the exhaust chamber and the exhaust manifold. A flow is connected between two turning chambers provided in the end region, said turning chambers being open to their corresponding respective collecting (exhaust summing) shaft portions, and to each said collecting shaft portion. Inflows a partial quantity of the corresponding exhaust connection pipe. Furthermore, these parts of the catalyst device have a segment-shaped cross section in which the outer side abuts the inner circumference of the exhaust manifold, and each of the collective shaft parts occupying the remaining cross section of the exhaust manifold is adjusted by a flow restrictor. It can be connected by at least one possible doorway.

Due to the above-mentioned means, a symmetrical arrangement is practically realized on the central radiation surface, so that the amount of exhaust gas deposited is preferably divided into two partial flows. These substreams are collected independently of one another in their corresponding collecting shaft sections and then flow through their respective assigned catalytic device sections. By dividing in this way, only a half volume flow is processed in each individual part, so that the flow cross section can be relatively small. This allows for a very compact construction, which is highly desirable in view of the limited location of machine rooms such as ships. A further advantage of the measure according to the invention is that if a part of the catalytic device is missing, only the partial volume flow of exhaust corresponding to this part needs to be sent untreated directly to the exhaust chamber. In that case, the flow restricting device provided in the inlet / outlet region to the exhaust chamber may be partially opened. The other partial volume flow is independent of this and flows through the corresponding catalytic converter section without obstruction. Therefore, the reduction process of a partial amount of the exhaust gas is maintained, which meets certain regulations and is sufficient to prevent the entire engine from shutting down. Therefore, the measures according to the invention offer excellent economics. What is furthermore ensured by the means according to the invention is that the individual parts of the catalytic device are directly accessible from the outside by removing the lid of the exhaust manifold adjacent to them, respectively, whereby maintenance and Very easy to assemble. Since the exhaust chamber can be connected to the collecting shaft portion through the opening / closing port, the exhaust pipe extending from the exhaust chamber can be driven not only during the driving of the catalyst device but also during the partial driving of the catalyst device. Can be used reliably even during bypass drive. Therefore, a separate bypass pipe is not required. From the above description it can be seen that the present invention completely prevents the disadvantages of the first known device.

Preferred constructions of the means described in the preamble and further constructions suitable for the purpose are set forth in the subclaims. Therefore, the segment-shaped cross section of the catalyst device part can also be suitably formed as an annular segment open towards the open area of the exhaust connection pipe.
Thereby corresponding to said collecting shaft part,
A centrally provided passage surrounded by the corresponding catalytic device portion is provided with a radial, outwardly funnel-like expanding inlet slit into and into the inlet slit. The exhaust connection pipe can provide exhaust. By such means the exhaust can be successfully guided in a suitable manner.

It is also possible to suitably form the annular segment as a polygonal slide member that opens toward the open area of the exhaust connection pipe. This facilitates manufacturing and preferably provides an edge that can serve as a guide edge, against which rails can be provided, which facilitates installation and removal.

A further preferred means is that the two collecting shaft parts are connected to each other via a coupling chamber adjacent to the exhaust chamber, and an inlet / outlet adjustable by a flow restrictor is provided between the coupling chamber and the exhaust chamber. Is to be done. With such a configuration, the two collecting shaft portions can be coupled to the exhaust chamber through the same inlet / outlet port, and as a result,
Only one current limiting device is needed. A further advantage is that in the event of a disturbance, the exhaust volume flow deposited in one collecting shaft part region can be at least partly also supplied to the other collecting shaft part, whereby a catalytic device corresponding to this collecting shaft part can be provided. It is to be conveyed through a part.

It is also possible to suitably provide the exhaust manifold with an interior member that defines passages corresponding to the catalyst device portion and the collecting shaft portion. In that case,
The catalytic device members forming the catalytic device portion can be easily pushed into the corresponding passages, which facilitates installation and maintenance.

The individual parts of the catalytic converter preferably have at least one oxidation catalytic converter member and a number of NOx (nitrogen oxide) catalytic converter members. With such a structure, soot and nitrogen oxides are reliably reduced.

The reducing agent necessary for performing the above-mentioned reduction is suitably added to and mixed with the exhaust gas by the injection valve provided in the exhaust connection pipe region. Mixing is sufficiently performed by such means, and the reducing agent is uniformly dispersed. A further advantage is that in the present invention the amount of reducing agent mixed in can be individually adjusted depending on the combustion ratio in the corresponding cylinder. If the parts of the catalytic device corresponding to the individual exhaust connection pipes have to be blocked, it is also possible to stop the injection of reducing agent into these individual exhaust connection pipes.

Further preferred configurations and further configurations suitable for the purpose of the above-mentioned means are described in the embodiments described below on the basis of the remaining subclaims and the drawings.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The following figures show the following. FIG. 1 is a partial cross-sectional view of a large diesel engine according to the present invention. 2 is a longitudinal cross-sectional view of the exhaust manifold of the apparatus of FIG. Figure 3
FIG. 3 is a sectional view taken along line III-III in FIG. 2.

The structure and function of large diesel engines, such as two-stroke large diesel engines, are well known per se and need not be described in more detail in the context of the present invention. FIG. 1 shows the upper region of a two-stroke large diesel engine. The two-cycle large-scale diesel engine includes a large number of cylinders 1 arranged in a row and adjacently
The cylinder is provided with an exhaust valve 2 distributed to each cylinder cover, the exhaust passage can be opened or closed by the exhaust valve, and an exhaust connection pipe 3 is connected to the exhaust valve. An exhaust manifold 4 is provided in parallel with the row of cylinders, all exhaust connection pipes 3 are opened to the exhaust manifold, and an exhaust pipe 6 leading from the exhaust manifold to a turbine of an exhaust turbocharger 5 is branched. The exhaust connection pipe 3 has a diffuser-shaped end portion 7 protruding into the tubular exhaust manifold.
Is provided. An insulating sleeve 8 may be provided on the exhaust connecting pipe 3 so that the exhaust does not cool.

The exhaust manifold 4 has a tubular casing 9 which can be closed by a removable end 10 as shown in FIG. The tubular casing 9 has a catalyst device 17 through which the exhaust can flow to reduce soot and nitrogen oxides contained in the exhaust, and a collecting shaft device 26 provided in front of the catalyst device. The end 7 of the exhaust connection pipe 3 is opened to the device. A reducing agent such as ammonium or urea is supplied to the exhaust gas upstream of the catalyst device 17.
The reducing agent is injected into the exhaust connection pipe 3. Since the exhaust gas is sufficiently mixed with the exhaust gas in the exhaust connection pipe 3, the reducing agent is uniformly dispersed. Such an effect is further supported by the end portion 7 having a cylindrical shape.

As can be further seen from FIG. 1, in order to inject the reducing agent, each said exhaust connection pipe 3 is provided with a suitable injection valve 11, said injection valve being provided with a supply pipe 1.
The reducing agent such as ammonium or urea is supplied via 2 and can be controlled by the signal line 14 branched from the control device 13. All the reducing agent injection valves 11 can be controlled by the control device 13 as indicated by a further signal line branching from the control device 13. The control unit 13 is provided in advance with a machine cycle, as indicated by the signal line 15. For this purpose, for example, a crankshaft can be used, but it is also conceivable to use a signal for operating the exhaust valve 2. In any case, this causes the injection valve 11 to be activated only when the corresponding exhaust valve 2 is also open, that is to say when exhaust is taking place. Although the injection amount can be fixedly determined, the injection amount can be individually determined for each injection valve 11 according to the combustion ratio in each cylinder. For this purpose, the control device is supplied with corresponding data such as the temperature of the combustion chamber, as indicated by the signal line 16 in FIG.

The catalyst device and the collecting shaft device 26 provided in the casing 9 of the exhaust manifold 4 are
Two catalytic device parts 17a, 1 as described in FIG.
7b and collecting shaft portions 26a, 26b, which are provided on both sides of an exhaust chamber 18 provided at the center of the exhaust manifold 4, and an exhaust pipe 6 for carrying exhaust gas from the exhaust chamber branches. Therefore, it is configured as a mirror image of the radial left and right symmetrical surfaces.

The two parts 17a, b of the catalytic device consist of a number of catalytic device members which are arranged in the front and rear respectively and are constructed according to a static mixing device in a known manner, the catalytic device members in this case being separated by a distance. The holding devices 19 provide a distance from each other. First, the nitrogen oxide catalyst device member 20 is provided. In the embodiment shown in the figures, the individual catalyst device parts 17a, 17b further have an oxidation catalyst device member 21 in addition to the nitrogen oxide catalyst device member 20, by which soot particles are removed. . The oxidation catalyst device member 21 is shown in FIG.
Although it is provided at the exhaust inlets of a and b, it may be provided at another place, for example, in the exhaust outlet region.
As indicated by the solid arrows in FIG. 2, for the catalytic device members 20, 21 flow through parallel to the longitudinal axis of the casing 9 and for the two parts 17a, b in opposite, opposite flow directions. Occurs.

As shown in FIGS. 1 and 3, the catalyst device members 20, 21 are formed as annular segments open toward the open region of the exhaust connection pipe 3 and are eccentrically provided on the exhaust manifold 4. It has a segment cross section, and the outer surface of the segment cross section abuts the inner circumference of the tubular casing 9 of the exhaust manifold 4. Said tubular segment-shaped cross section is formed as a polygonal slide member open towards the open area of said exhaust connection pipe 3, as further illustrated by FIGS. 1 and 3, whereby said catalytic device member. Manufacturing of 20 and 21 and its attachment become easy. The catalyst device members 20, 21
Casing 9 of said exhaust manifold 4 for receiving
In the regions corresponding to the two catalytic device parts 17a, b of the above, respectively, a separating wall 22 is provided, and this separating wall has a contour according to the inner contour of the annular segment cross section of the members 20,21. A first eccentric passage having a cross section corresponding to that of the catalytic device member 20, 21 is thereby separated from a second passage occupying the remaining cross section of the interior space of the casing 9.

The second passages are respectively formed corresponding to the adjacent catalyst device parts 17a and 17b, respectively, and the collecting shaft part 26a provided in front of the catalyst device parts in the direction of exhaust gas flow. , 26b, and a corresponding number of exhaust connection pipes are opened toward the collecting shaft portion. The individual collecting shaft parts 26a, b are preferably distributed with half of the exhaust connection pipe 3 and thus of half of the cylinder 1. The collecting shaft portions 26a, 26b correspond to corresponding catalyst device portions 17 as indicated by the dashed arrows in FIG.
Contrary to a and b, it flows from the inside to the outside.

The catalytic device members 20, 21 respectively distributed to the catalytic device parts 17a, 17b can be pushed into the respective first passages. This is done from the end of the casing 9 each time the lid 10 is removed. In this way, the two parts 17a, b of the catalytic device can be constructed independently of each other. The contours of the annular segments of the catalytic device members 20, 21 corresponding to the open polygonal slide members form edges and a plane extending between the edges, as shown in FIGS. The guide rails 24 provided in the region of the separation wall 22 and the region of the inner circumference of the casing 9 can be distributed on the plane of
The catalyst device members 20 distributed on those rails,
21 are pushed into the corresponding passages. The catalyst device members pushed into the corresponding passages are fixed stoppers 1 at the front in the pushing direction.
9a and is held by a holding plate 25 which is detachably fixed to the separating wall 22 at the rear side in the pushing direction.

The second passage formed by the separating wall 22, which functions as the collecting shaft portion 26a, b,
As can be seen best from FIG. 1, it has a central passage area coaxial to said casing 9, which transitions radially into an inflow slit which is funnel-shaped opening towards the outside. The end portion 7 of the exhaust connection pipe 3 which is formed in the shape of a scattered cylinder and projects into the casing 9 has the end portions 7a, 26b,
It is provided so as to exhaust to the slit of b. In the example shown in the figure, the axis of the end is provided in a symmetrical plane containing the longitudinal axis of the casing 9, which creates an inlet flow in a direction aligned with the center of the central passage area. .

The passages functioning as the collecting shaft portions 26a, 26b are closed from the exhaust chamber 18 by a side wall 27 provided on the end face side of the separating wall 22. The passages distributed to the catalyst device members 20 and 21 are open toward the exhaust chamber 18. The two passages 23, 26 are open in the opposing partial end regions on the lid side.
Each of the separating walls 22 terminates with a certain distance from the adjacent lid 10, so that even the rearmost catalytic device member in the pushing direction has a corresponding adjacent lid 10.
And have a distance. This creates a diverting chamber 28 in the end region of the casing 9 by means of which the individual catalytic device parts 17a, b are arranged in the flow direction in the corresponding collecting shaft parts 26a, 26b.
Is connected according to the flow.

Accordingly, on both sides of the exhaust chamber 18, the corresponding collecting shaft portions 26a and 26b from the exhaust connecting pipe 3 and the catalyst device portion 17 provided behind the collecting shaft portions 26a and 26b, respectively.
A flow path is created to reach the exhaust chamber 18 via a and b. Exhaust gas injected from the exhaust connection pipe 3 into the corresponding collecting shaft portions 26a, 26b is first redirected in the end region of the casing 9, as indicated by the dashed arrow in FIG. It flows into the chamber 28 and from the diverting chamber it reaches the exhaust chamber 18 via the corresponding catalytic device parts 17a, b, respectively, as indicated by the arrows shown in solid lines in FIG.

The collecting shaft portions 26a and 26b provided on both sides of the exhaust chamber 18 are coupled to each other by a coupling shaft 29 which penetrates the lower portion of the exhaust chamber 18. A window-shaped inlet / outlet 30 is provided between the coupling shaft 29 and the exhaust chamber 18, and a flow restrictor 31 is provided at the inlet / outlet.
2 are distributed by the flow restrictor,
Closed or opened as indicated by the dashed line at.
The flow restricting device 31 can be formed as a double-opening type or a winding type cover device. The current limiting device 31 is preferably drivable by a motor 32 shown in FIG.

As soon as the flow restrictor 31 is opened, a flow path is created which bypasses the catalyst device parts 17a, b and directly leads from the collecting shaft parts 26a, b to the exhaust chamber 18. Such a path is used, for example, when high output must be supplied to the exhaust supercharger for a short period of time. The same applies if the catalytic device area is disturbed. As long as such an obstacle occurs only in one of the two catalyst device parts 17a and 17b, the flow restrictor 31 is only partially opened, so that the defective catalyst device part 17a or 17b. Only the exhaust volume flow rate corresponding to the above directly reaches the exhaust chamber 18,
The exhaust volume flow rate corresponding to the respective other catalyst device part 17b or a is led via said corresponding catalyst device part and is thus cleaned. In that case, naturally, the reducing agent is supplied only to the exhaust gas flowing through the corresponding catalyst device portion 17a or 17b. The injection valves 11 provided on the exhaust connection pipes 3, which are respectively distributed to the other part, are then shut off.

[Brief description of drawings]

FIG. 1 shows a part of a large diesel engine according to the invention in partial section.

2 is a longitudinal cross-sectional view of the exhaust manifold of the apparatus of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

[Explanation of symbols]

3 Exhaust connection pipe 4 exhaust manifold 17a, 7b Catalytic device part 18 Exhaust chamber 26a, 26b Collecting shaft portion 28 Turn-around room 31 Current limiting device

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-117222 (JP, A) JP-A-49-61514 (JP, A) JP-A-4-232324 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) F01N 3/08-3/28 F01N 7/10

Claims (17)

(57) [Claims] 1. A large diesel engine, in particular a two-stroke large diesel engine with a large number of cylinders (1), each cylinder of which is preferably tubular through at least one exhaust connection pipe (3). An exhaust pipe (6) formed and connected to an exhaust manifold (4) whose end can be closed with a lid.
And the exhaust manifold has a catalyst device, and a gas capable of supplying a reducing agent is circulated to the catalyst device by a supply device provided upstream of the catalyst device, and the exhaust manifold (4 ) Exhaust chamber (18)
Is provided, and the exhaust pipe (6) branches from the exhaust chamber,
The exhaust chamber allows the catalyst device to have two parts (17
a, 17b), these parts connecting the flow between the exhaust chamber (18) and two diverting chambers (28) provided in the end region of the exhaust manifold (4), The turning chambers are opened to the corresponding collecting shaft portions (26a, 26b), and the corresponding partial amounts of the exhaust connection pipes (3) flow into the collecting shaft portions, respectively. 17a, 17b) has a cross-section that is segment-shaped and the outside abuts the inner circumference of the exhaust manifold (4), and occupies the remaining cross-section of the exhaust manifold (4). Is a flow restrictor (3
1) at least one entrance (3) adjustable by
A large diesel engine characterized in that it can be connected to the exhaust chamber (18) via the (0). 2. The parts (17a, 17a) of the catalytic device.
2. Large diesel engine according to claim 1, characterized in that the segmental cross section of b) is formed as an annular segment open towards the open area of the exhaust connection pipe (3). 3. The parts (17a, 17a) of the catalytic device.
3. The segmental cross section of b) is formed as a polygonal slide member open towards the open area of the exhaust connection pipe (3).
Large diesel engine described in. 4. The collecting shaft portions (26a, 26a)
b) The exhaust is guided through the radial inlet slots
Has a central region in that, large diesel according to any one of claims 1 to 3, wherein the exhaust connection pipe corresponding toward said central area (3) is characterized in that it is open engine. 5. The assembly shaft portions (26a, 26)
b) a coupling shaft (2) adjacent to the exhaust chamber (18)
9) via the coupling shaft and the exhaust chamber (18), the inlet / outlet (30) being adjustable by a flow restrictor (31). The large diesel engine according to any one of claims 1 to 4. 6. The large diesel engine according to claim 1, wherein the flow restrictor (31) is formed as a folding device. 7. The exhaust chamber (18) is separated from the collecting shaft portion by a side wall (27) shaped substantially corresponding to the cross-section of the collecting shaft portion (26a, 26b). Claims 1 to 6
Large diesel engine described in any one of. 8. A separation wall (2) is attached to the exhaust manifold (4).
2) is installed, and these separating walls have passages corresponding to the members of the corresponding parts (17a, 17b), respectively.
Large diesel engine according to any one of the preceding claims, characterized in that it is provided between the corresponding passage forming the collecting shaft part (26a, 26b). 9. The large size according to claim 1, wherein members of the catalyst device portions (17a, 17b) are provided so as to be movable on slide rails. diesel engine. 10. The device according to claim 1, characterized in that the catalyst device parts (17a, 17b) provided in the respective corresponding passages can be fixed by means of a retainer (25) provided on the cross section of the passage. A large diesel engine according to any one of paragraphs 9. 11. The catalyst device portion (17a, 17b)
A number of members (2
0, 21), wherein the large diesel engine according to any one of claims 1 to 10. 12. The large diesel engine according to claim 1, wherein the members (20, 21) are separated from each other by a distance holder (19). 13. The individual catalyst device parts (17a, 1)
7b) is at least one oxidation catalyst device member (21)
And a large number of nitrogen oxide catalyst device members (20), The large diesel engine according to any one of claims 1 to 12. 14. The method according to claim 1, wherein the reducing agent can be mixed with the exhaust gas by an injection valve (11) provided in the exhaust connection pipe (3) region. Large diesel engine. 15. The injection valve (11) is a control device (1).
3. It can be controlled by 3).
The large diesel engine described in 4. 16. The exhaust connection pipe (3) has a cylindrical end portion (7) projecting from the corresponding collecting shaft portion (26). The large diesel engine according to claim 15. 17. The axis of the end portion (7) of the exhaust connection pipe (3) is provided on a radial symmetrical surface including the longitudinal axis of the casing (9) of the exhaust manifold (4). The large diesel engine according to any one of claims 1 to 16.