DE102018125132A1 - Exhaust gas aftertreatment system of an internal combustion engine - Google Patents

Abstract

Exhaust gas aftertreatment system (1) of an internal combustion engine, with a housing (4), the housing (4) having a first flow cross-sectional area (A1), with a feed line (2) leading to the housing (4), via which exhaust gas emanating from the internal combustion engine in the direction can be guided onto the housing (4), the feed line (2) having a second flow cross-sectional area (A2), the feed line (2) merging into the housing (4) with a step-like or sudden expansion of the flow cross-sectional area such that A1≥1 , 2 * A2, and wherein a funnel-like or cone-like spark arrester (5) is arranged inside the housing (4), which has an opening (6) pointing in the direction of the feed line (2) and a surface A3 projected in the flow direction, A2 ≤A3 <A1.

Description

The invention relates to an exhaust gas aftertreatment system of an internal combustion engine.

In internal combustion engines that burn a liquid fuel, especially in four-stroke or two-stroke engines, such as those used on ships, glowing soot particles can form in the exhaust gas of the internal combustion engine. In order to prevent fires caused by such glowing soot particles from escaping, it is known in practice to use so-called spark arresters or spark arresters.

So it shows GB 2 374 385 A an arrangement of a silencer and a spark arrester, which are arranged in an exhaust tract of an internal combustion engine. Such a spark arrester known from practice has a relatively large size and a relatively complex structure. Typically, spark arresters according to the prior art are arranged at the end of the exhaust gas line, ie downstream of catalysts.

Proceeding from this, the object of the invention is to create a novel exhaust gas aftertreatment system of an internal combustion engine.

This object is achieved by an exhaust gas aftertreatment system of an internal combustion engine according to claim 1. According to the invention, the feed line merges into the housing with a step-like or sudden expansion of the flow cross-sectional area such that A1≥1.2 * A2. According to the invention, a funnel-like or cone-like spark arrester is arranged inside the housing, which has an opening pointing in the direction of the feed line and a surface projected in the direction of flow A3 has, wherein A2≤A3 <A1.

In the exhaust gas aftertreatment system according to the invention, using a compact spark arrester with a simple construction can effectively prevent glowing soot particles from escaping from the exhaust system.

According to an advantageous development, the spark arrester is at a distance within the housing x from an opening point of the supply line, which is round in cross section, arranged in the housing, where x≤2 * d, where d is the diameter of the supply line. Such a distance of the spark arrester from the mouth of the feed line into the housing, that is to say the distance of the spark arrester from the step-like or sudden expansion of the flow cross-sectional area, is particularly preferred in order to effectively catch glowing soot particles.

According to an advantageous development, the spark arrester has an opening angle α on, where 35 ° ≤α≤170 °. Such an opening angle of the spark arrester is particularly preferred in order to effectively catch glowing soot particles.

According to an advantageous development, the spark arrester is closed in the direction of flow. This further training also serves to effectively catch glowing soot particles.

According to an advantageous further development, the spark arrester is arranged in the housing in such a way that the opening facing the feed line or facing the feed line is open at the bottom. Captured soot particles can fall down onto a housing wall in the housing. When the engine is started, these particles are whirled up and can then be discharged from the exhaust gas aftertreatment system as cooled soot particles.

According to an advantageous further development, walls of the spark arrester have projections which point in the direction of the feed line and which define flow dead zones or pockets. The separation of glowing soot particles can be further improved via the projections.

• 1 eine stark schematisierte Ansicht eines erfindungsgemäßen Abgasnachbehandlungssystems einer Brennkraftmaschine.
• 1 zeigt einen stark schematisierten Ausschnitt aus einem Abgasnachbehandlungssystem 1 einer Brennkraftmaschine, insbesondere einer einen Flüssigkraftstoff verbrennenden, als Viertaktmotor oder Zweitaktmotor ausgebildeten Brennkraftmaschine eines Schiffs.

Preferred developments of the invention result from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being restricted to this. It shows:

• 1 a highly schematic view of an exhaust gas aftertreatment system of an internal combustion engine according to the invention.
• 1 shows a highly schematic section of an exhaust gas aftertreatment system 1 an internal combustion engine, in particular an internal combustion engine of a ship, which burns a liquid fuel and is designed as a four-stroke engine or two-stroke engine.

1 shows a supply line 2nd of an exhaust gas aftertreatment system, via the exhaust gas 3rd , which arises during the combustion of the liquid fuel in the area of an internal combustion engine, not shown, in the direction of a housing 4th to conduct in which a spark arrester 5 is arranged.

The housing 4th in which the spark arrester 5 is included, has a first flow cross-sectional area A1 . The housing 4th leading supply line 2nd over which the exhaust gas 3rd starting from the internal combustion engine in the direction of the housing 4th is guided, has a second flow cross-sectional area A2 .

To with a simple construction and compact construction of the spark arrester 5 an effective separation of glowing soot particles from the exhaust gas 3rd it is envisaged that the supply line 2nd in the housing 4th with a step-like or sudden expansion of the flow cross-sectional area, in such a way that A1≥1.2 * A2. The cross-sectional area for the exhaust gas widens at the transition of the supply line 2nd in the housing 4th accordingly in steps or abruptly by at least 20%. The inside of the case 4th positioned spark arrestors 5 is funnel-like or cone-shaped, this funnel-like or cone-like spark arrester 5 one towards the supply line 2nd pointing opening 6 having through walls 7 of the spark arrester 5 is defined. The walls 7 which the towards the feed line 2nd pointing opening 6 of the spark arrester 5 define, converge in the flow direction or diverge against the flow direction of the exhaust gas 3rd . The spark arrester 5 has a surface projected in the direction of flow A3 on. A2≤A3 <A1 applies. As a result of that A3 smaller A1 there is a distance between the walls 7 of the spark arrester 5 and the housing 4th , so the exhaust 3rd , which is in the area of the spark arrester 5 is redirected between spark arresters 5 and walls of the housing 4th can flow past and then out of the housing 4th to be derived.

For a particularly advantageous separation of glowing soot particles in the area of the spark arrester 5 to enable, applies in particular A1≥1.35 * A2, preferably A1≥1.5 * A2. In the area of the mouth of the supply line 2nd in the housing 4th Accordingly, the flow cross section for the exhaust gas expands in particular by at least 35%, preferably by at least 50%.

It is also preferred if A3≥1.1 * A2, particularly preferably A3≥1.2 * A2. In any case, A3 <A1 applies. Then when the area projected in the direction of flow A3 of the spark arrester is larger than the area by at least 10%, preferably by at least 20% A2 the supply line 2nd , the exhaust gas in the area of the cone-like or funnel-like spark arrester 5 deflected particularly strongly, so that glowing soot particles are particularly advantageous in the area of the spark arrester 5 can be separated.

For an advantageous separation of glowing soot particles in the area of the cone-like or funnel-like spark arrester 5 it is further preferred if the spark arrester 5 , namely that of the supply line 2nd facing opening 6 the same, inside the housing 4th with a defined distance x from the mouth of the supply line 2nd in the housing 4th is arranged and / or if the spark arrester 5 a defined opening angle α its the opening 6 defining walls 7 having.

For the distance x of the spark arrester 5 at the mouth of the supply line 2nd in the housing 4th preferably x≤2 * d, i.e. 0≤x≤2 * d. Preferably 0 <x≤d, particularly preferably 0 <x ≤0.5 * d.

For the opening angle α of the spark arrester 5 applies 35 ° ≤α≤170 °. In particular, 50 ° ≤α≤150 ° applies, preferably 70 ° ≤α≤130 °.

As already stated, the ratios of the flow cross sections defined above serve A1 and A2 , the ratios of the surface projected in the direction of flow defined above A3 of the spark arrester 5 to the flow cross-sectional area A2 the supply line 2nd , the distance defined above x the opening 6 of the spark arrester 5 from the supply line 2nd as well as the opening angle defined above α of the spark arrester 5 for the effective separation of glowing soot particles from the exhaust gas in the area of the spark arrester 5 .

The spark arrester 5 , which is contoured like a funnel or cone, and of which the opening 6 defining walls 7 in the flow direction of the exhaust gas 3rd converge, is closed in the direction of flow. The same is only on the supply line 2nd facing side through the opening 6 opened that towards the supply line 2nd or the mouth of the supply line 2nd in the housing 4th points.

Exhaust gas 3rd which via the supply line 2nd in the housing 4th occurs, is on the spark arrester 5 redirected. The redirected exhaust gas flows at the spark arrester 5 over, especially towards one in the case 4th positioned catalyst or particulate filter 8th . Soot particles cannot follow the exhaust gas flow due to their inertia and flow through the opening 6 in the spark arrester 5 and are caught there.

In the exemplary embodiment of the invention shown, it is provided that the walls 7 of the spark arrester 5 towards the supply line 2nd pointing projections 9 exhibit. The tabs 9 accordingly extend in the flow direction of the exhaust gas 3rd .

The walls 7 of the spark arrester 5 define along with these tabs 9 Bags or current dead zones 10th , thereby separating or collecting glowing soot particles from the exhaust gas 3rd in the area of the spark arrester 5 is improved.

In in 1 The preferred exemplary embodiment of the invention shown is the spark arrester 5 in the housing 4th arranged so that the on the feed line 2nd pointing opening 6 of the spark arrester 5 is not aligned horizontally but rather vertically, so that the opening 6 ultimately down pointing openly, so that in the area of the spark arrester 5 deposited soot particles from the cone or funnel of the spark arrester 5 fall down and down on a bottom wall or bottom wall of the case 4th can deposit.

If the internal combustion engine is restarted after it has come to a standstill, these cooled soot particles are whirled up and can be discharged via the exhaust system, so that it is not necessary to periodically clean the spark arrester.

To further improve spark separation, the spark arrester can be installed downstream 5 a honeycomb catalyst element 8th be arranged. The opening of the catalyst channels is so on the spark arrester 5 matched that small, glowing particles that due to their low weight do not have the deflection on the spark arrester 5 can be deposited on the catalyst element 8th is intercepted.

For this, as already stated, is in the housing 4th of the spark arrester 5 preferably a catalyst 8th arranged. With such catalysts 8th it is a honeycomb-shaped body, the use of a honeycomb-shaped body with a cell structure of at least 35 cpsi (cells per square inch), preferably of at least 60 cpsi, particularly preferably of at least 80 cpsi, is preferred to collect soot particles in the area of a particle filter. This can further improve exhaust gas aftertreatment.

A further improvement consists in using a particle filter, preferably based on ceramic or metallic substrates, instead of or in addition to the honeycomb-shaped catalyst module.

The invention is preferably used in four-stroke or two-stroke engines in which a liquid fuel is burned, in particular when the kinematic viscosity of the fuel at 40 ° C. is above 5 mm ² / sec, in particular above 20 mm ² / sec. The cetane index of the liquid fuel, which defines the ignitability of the liquid fuel, is below 45.5, in particular below 41. When liquid fuels with such a viscosity and / or such a cetane index are burned in an internal combustion engine, the invention preferably comes in combination with one in the flow direction downstream of the spark arrester 5 positioned catalyst or particulate filter 8th particularly advantageous for use.

Reference list

1

Exhaust aftertreatment system

2nd

Supply

3rd

Exhaust gas

4th

casing

5

Spark arrestor

6

opening

7

wall

8th

Catalytic converter / particle filter

9

head Start

10th

Current dead zone

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• GB 2374385 A [0003]

Claims (11)

Exhaust gas aftertreatment system of an internal combustion engine, with a housing (4), the housing (4) having a first flow cross-sectional area (A1), with a feed line (2) leading to the housing (4), via which exhaust gas emanating from the internal combustion engine in the direction of the housing (4) is feasible, the feed line (2) having a second flow cross-sectional area (A2), characterized in that the feed line (2) merges into the housing (4) with a step-like or sudden expansion of the flow cross-sectional area such that A1≥1 , 2 * A2; a funnel-like or cone-like spark arrester (5) is arranged inside the housing (4) and has an opening (6) pointing in the direction of the feed line (2) and a surface A3 projected in the direction of flow, where A2≤A3 <A1. Exhaust aftertreatment system after Claim 1 , characterized in that $$\text{A}1\ge 1.35*\text{A}\mathrm{2,}$$

preferably A1≥1.5 * A2. Exhaust aftertreatment system after Claims 1 or 2nd , characterized in that $$\text{A}\mathrm{3rd}\ge 1.1*\text{A}\mathrm{2,}$$

preferably A3≥1.2 * A2. Exhaust aftertreatment system according to one of the Claims 1 to 3rd , characterized in that the spark arrester (5) is arranged within the housing (4) at a distance x from an opening point of the supply line (2), which is round in cross section, into the housing (4), where x≤2 * d, where d is the The diameter of the feed line (2) is. Exhaust aftertreatment system after Claim 4 , characterized in that $$0<\text{x}\le \mathrm{2nd}*\text{d},$$

preferably 0 <x≤1 * d, particularly preferably 0 <x≤0.5 * d. Exhaust aftertreatment system according to one of the Claims 1 to 5 , characterized in that the spark arrester (5) has an opening angle α, where 35 ° ≤α≤170 °. Exhaust aftertreatment system after Claim 6 , characterized in that $$50°\le \mathrm{\alpha }\le 150°,$$

preferably 70 ° ≤α≤130 °. Exhaust aftertreatment system according to one of the Claims 1 to 7 , characterized in that the spark arrester (5) is closed in the direction of flow. Exhaust aftertreatment system according to one of the Claims 1 to 8th , characterized in that the spark arrester (5) is arranged in the housing (4) in such a way that the opening (6) pointing towards the feed line (2) is open at the bottom. Exhaust aftertreatment system according to one of the Claims 1 to 9 , characterized in that walls (7) of the spark arrester (5) have projections (9) pointing in the direction of the feed line (2), which define flow dead zones (10) or pockets. Exhaust aftertreatment system according to one of the Claims 1 to 10th , characterized in that a catalyst or particle filter (8) is accommodated in the housing (4), the funnel-like or cone-like spark arrester (5) being positioned upstream of the catalyst or particle filter (8).

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