JP2019523361A - Silencer for single cylinder diesel engine - Google Patents

Abstract

In a silencer for a single cylinder diesel engine with a built-in oxidation catalyst, the silencer is connected to the cylinder head of the engine, and the silencer housing is divided into two chambers, an inflow chamber and an outflow chamber, by an intermediate wall (3); An oxidation catalyst (28) is fixed to the intermediate wall (3) in such a way that both chambers are fluidically coupled to each other. [Selection] Figure 4

Description

  The present invention relates to a silencer for a single cylinder diesel engine having the oxidation catalyst according to the preamble of claim 1.

  Such prime movers are well known. The German Patent Application Publication No. 10139700 (A1) and JP-A-2015-143510 can be cited. This is preferably used to drive construction machinery or as a fixed low power prime mover.

  At that time, the required performance of exhaust gas purification / detoxification varies. In many cases, exhaust gas treatment using an oxidation catalyst is sufficient, that is, oxidation of CO components in the exhaust gas to CO2 and oxidation of hydrocarbons to CO2 and water.

When retrofitting an oxidation catalyst to an existing single-cylinder diesel engine, it is necessary to consider the mechanical structure to add an oxidation catalyst to an existing silencer while preventing unnecessary vibration load and not changing the natural frequency of the entire system. There is. By this method, it is possible to prevent damage to the machine tool connected to the drive device.

  Accordingly, an object of the present invention is to combine an oxidation catalyst and a silencer in an appropriate manner while avoiding the above-mentioned problems, in particular, the reduction of the natural frequency and the accompanying resonance breakdown.

  In order to solve the above problems, according to the present invention, the silencer housing is directly coupled to the cylinder head by flange coupling, and the intermediate wall (3) has an opening for hermetically mounting the assembly work pipe (14), The assembly work pipe traverses the silencer housing and is assigned to the connection hole (15) of the connection flange to form a screw connection between the connection flange (9) and the corresponding cylinder head flange member at the end on the engine side. It is fixed inside the connection flange (9) on the silencer side.

  This scheme allows the additional weight loaded into the silencer by the oxidation catalyst to be received by the intermediate wall and distributed throughout the silencer housing. In this case, the natural frequency of the silencer can be suppressed within a limit range, and as a result, resonance damage to the silencer housing or the entire device such as a vibration compactor used in the construction industry can be prevented.

  The application of diesel oxidation catalysts relates to the oxidation of carbon monoxide (CO) to carbon dioxide (CO2) and the oxidation of hydrocarbons (CnHm) to carbon dioxide (CO2) and water in the exhaust gas. Within the framework of the invention, a high exhaust gas temperature advantageous for oxidation is achieved by the fact that the silencer has a flange connection and can thus be directly connected to the cylinder head.

  According to a very preferred configuration in this respect, the intermediate wall is provided with an opening for airtight insertion of the assembly work tube, which crosses the silencer housing and connects the connection flange at the end on the engine side. It is fixed to the connection flange on the silencer side while assigning it to the hole.

  The robust and vibration-resistant embodiment according to the present invention is formed by air-tightly welding a silencer side connection flange to a raised portion of a silencer housing that circulates around the circumference of the connection flange.

  According to the invention, the intermediate wall itself is hermetically fixed between two independent housing members of the silencer housing, i.e. fixed between the housing rear wall facing the engine and the housing lid member. Both housing members are welded to the intermediate wall in a circular fashion.

  The intermediate wall is preferably formed in a bowl shape having a convex curve toward the exhaust gas flowing into the inflow chamber of the silencer. Thereby, the strengthening of the intermediate wall and accordingly the rigidity of the entire silencer housing is improved.

  The catalyst body itself penetrates the intermediate wall and is hermetically accommodated in the opening of the intermediate wall. Therefore, untreated exhaust gas passes from the inflow chamber formed by the rear wall of the housing through the catalyst body and flows into the outflow chamber separated by the housing lid member, and then flows into the exhaust pipe of the engine as treated exhaust gas. To do.

  According to the present invention, a very stable fixation of the closed inner end of the exhaust pipe is achieved by providing an opening for the intermediate wall to hermetically accommodate the inner end of the exhaust pipe.

  Therefore, according to another preferred configuration of the exhaust pipe holder inside the silencer housing, said inner end projects into the inflow chamber of the silencer housing, where there is a corresponding recess in the rear wall of the silencer housing. It is slidably supported inside.

  For the purpose of keeping the vibration in the silencer housing as low as possible, the housing itself is provided with beading formed in all directions and the coined shape of the housing member equivalent to it, which not only acts as a reinforcement but also resonates. It is also effective to prevent. The perforation structure of the exhaust pipe in the area inside the outflow chamber of the silencer housing according to the invention also serves the same purpose.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view of the silencer along line II in FIG. 2. It is explanatory drawing seen in the direction which faced the housing rear wall of the silencer provided with the connection flange. It is the three-dimensional view which showed the housing cover member and the exhaust pipe which protrudes from there. FIG. 4 is a cross-sectional view of the silencer along line IV-IV in FIG. 3. It is explanatory drawing which showed the example of a change of sectional drawing of FIG. It is the three-dimensional view which showed the housing rear wall which concerns on the example of a change of FIG.

  The silencer housing shown in the accompanying drawings includes a housing rear wall 1 and a housing lid member 2 between which an intermediate wall 3 is fixed. The intermediate wall 3 extends hermetically across the entire silencer housing; has a bowl shape and has a convex curvature towards the inflow chamber 4 formed by the housing rear wall 1; On the side of this, the outflow chamber 5 formed by the housing lid member 2 is partitioned. The intermediate wall 3 is provided with a rounded curved coupling edge 6 into which the open end 7 of the corresponding housing lid member 2 enters, so that both housing members, namely the housing rear wall 1 and the housing lid member An airtight connection between the two is established, for example by welding.

  The catalyst body 28 of the oxidation catalyst extends from the inflow chamber 4 through the intermediate wall 3 into the outflow chamber 5 and is airtightly coupled to the intermediate wall. Exhaust gas from the cylinder head flows into the inside of the inflow chamber 4 in the direction of the arrow P1 through the flange connection of the connection flange 9 fixed to the rear wall 1 of the housing, and from there, the catalyst body 28 as shown by the arrow P2. Flow through. The exhaust gas processed in the catalyst body 28 reaches the outflow chamber 5 from the catalyst body 28, and then reaches the exhaust pipes 10 and 10 'for the processed exhaust gas (see FIGS. 4 to 6). The post-processed exhaust gas flowing out from the catalyst body 28 flows through the perforations 11 into the exhaust pipes 10 and 10 ', and further according to the arrows P3 and P3' through the exhaust gas passage (not shown) and the surrounding environment. To be discharged.

  As regards the shape design of the silencer housing, the housing rear wall 1 and the housing lid member 2 are reinforced in a multiple manner as indicated by the outline, for example, beading 12 in the region of the housing rear wall 1 (FIG. 4). Or in particular by the raised / recessed portions 13, 22 of the housing shell member in the connection area with other members. Such a coined shape provides the housing member of the silencer housing with high strength, thereby reducing the housing vibration tendency.

  Of course, it is understood that the built-in parts of the silencer housing passing through the housing wall or the intermediate wall are hermetically connected to the intermediate wall or the housing wall in the corresponding open areas, respectively, so that usually weld connections are used. This means that the catalyst body 28 passes through the intermediate wall 3, the exhaust pipe 10 passes through the housing lid member 2, the exhaust pipe 10 'passes through the housing rear wall 1 (FIG. 5), and the rear of the housing. This corresponds to penetration of the assembly work tube 14 shown in the embodiment through the wall 1, the intermediate wall 3, and the housing lid member 2. The three assembly work pipes 14 are fixedly coupled to the connection flange 9 at the end on the engine side. Therefore, an assembly tool inserted from the housing lid member 2 side via the assembly work pipe 14 is attached to the connection flange 9. The connection hole 15 (FIG. 2) can be reached. The fixing of the connection flange 9 to the flange member (not shown) of the corresponding cylinder head is carried out by screw connection to form a strong and airtight flange connection between the silencer housing on the one hand and the cylinder block on the other hand. Achieved by: Exhaust gas not treated by the flange packing (not shown) is prevented from reaching the inflow chamber 4 inside the housing rear wall 1 directly from the engine combustion chamber through the shortest path through the flange hole 16. The fixing points 17 on the outer surface of the housing lid member 2 and on the outer surface of the housing rear wall 1 function to fix the heat-resistant plate 28 schematically shown by the dotted lines in FIGS. It provides a contact prevention function to prevent combustion, extends along the outer surface of the housing lid member 2 and has a bent portion along the short side of the silencer housing.

  FIG. 4 shows the inner end of the closed exhaust pipe 10. The inner end of the exhaust pipe 10 is closed by the lid member 19. The end of the exhaust pipe 10 is slidably supported in a guide (not shown) relative to the adjacent housing rear wall 1.

  4 and 5 show a section IV-IV of the same silencer housing as in FIG.

  According to FIG. 4, the exhaust pipe 10 extends outwardly through the housing lid member 2 and has a purified exhaust gas flow indicated by the arrow P3.

  Another solution is shown in FIG. According to this, the exhaust pipe 10 'penetrates outwards through the housing rear wall 1 and has a purified exhaust gas flow indicated by the arrow P3'. The purified exhaust gas flows through the perforated tube portion 21 inside the outflow chamber 5 as indicated by the arrow P2 ′, and as indicated by the arrow P3 ′ via the exhaust pipe 10 ′ that crosses the inflow chamber 4 in an airtight manner. Reach the outside.

FIG. 6 shows a three-dimensional view of the silencer housing as viewed toward the housing lid member 2. As in the modification shown in FIG. 5, the exhaust pipe 10 ′ extends outward through the housing rear wall 1. The other points are the same as the silencer housing shown in FIG.

Claims (8)

  An oxidation catalyst is provided in a silencer housing connected to the cylinder head of the engine, wherein the silencer housing is divided into two chambers by means of an intermediate wall (3), both chambers being fluidically coupled to each other. The oxidation catalyst (28) is fixed to the intermediate wall (3) in such a manner, and the exhaust gas treated in the silencer chamber (5) placed behind the intermediate wall (3) as viewed in the flow direction is treated. A silencer for a single-cylinder diesel engine, which is airtightly connected to an exhaust pipe (10) for the engine, wherein the silencer housing is directly connected to the cylinder head by a flange connection, and the intermediate wall (3) is an assembly work pipe (14 ) In an airtight manner, the assembly work tube traverses the silencer housing and is connected to the connecting flange at the end on the engine side. (9) and fixed to the inside of the connection flange (9) on the silencer side while being assigned to the connection hole (15) of the connection flange to form a screw connection with the corresponding flange member of the cylinder head. Silencer.   2. Silencer according to claim 1, characterized in that the connection flange (9) on the silencer side is hermetically welded to the raised part (22) of the silencer housing which circulates around the periphery of the connection flange (9).   The silencer according to claim 1, characterized in that the intermediate wall (3) is hermetically fixed between two housing members of the silencer housing.   The silencer according to claim 1, characterized in that the intermediate wall (3) comprises an opening for the airtight insertion of the catalyst body (28).   2. A silencer according to claim 1, characterized in that the intermediate wall (3) is provided with an opening for hermetically accommodating the closed inner end of the exhaust pipe (10).   The inner end of the exhaust pipe (10) protrudes into the inflow chamber (4) of the silencer housing which is placed in front of the intermediate wall (3), where it enters the corresponding recess in the housing rear wall (1) of the silencer housing The silencer according to claim 5, wherein the silencer is slidably supported.   2. The silencer according to claim 1, wherein the exhaust pipe (10) forms a part of the silencer housing inside the outflow chamber (5) with perforation. The silencer according to claim 1, wherein the intermediate wall (3) is formed in a bowl shape having a convex curve toward the exhaust gas flowing into the inflow chamber (4) of the silencer.