DE2305818A1 - EXHAUST SYSTEM FOR COMBUSTION ENGINES - Google Patents

Description

DIPU-IN6. DR. IUR. DIPL.-ΙΝΘ.

VOLKER BUSSE DIETRICH BUSSE

45 Osnabrück , February 6, 1973

MOSERSTRASSE 2O / a4 L / Th

BRITISH LEYLAND MOTOR CORPORATION LIMITED Berkeley Square House, Berkeley Square, ' London .. England

Exhaust system for internal combustion engines

The invention relates to an exhaust system for internal combustion engines and is particularly found in exhaust systems for road vehicles Use.

The exhaust gases from internal combustion engines contain different Amounts of carbon monoxide, unburned hydrocarbons, nitrogen oxide, and macro-pollutants, causing air pollution and especially for the generation of smog in areas with strong solar radiation, which have a photochemical Effect, leads. Many methods have been developed and great efforts have been made to find harmful ones Reduce or eliminate components of the exhaust gases. A well-known one, commonly called a catalytic reactor designated device provides to lead the exhaust gases over a suitable chemical catalyst, so that the damaging

409832/0626

normal products are oxidized to more or less harmless products or be reduced. The disadvantage of such devices is that the life of the catalysts by different Factors is limited. To be effective, a catalytic converter must have a large area, to which the exhaust gases Have access. Most catalysts are applied to a material that is porous or permeable, so that the Exhaust gases can penetrate into this or migrate through it. Such catalysts are often in the form of pellets or spheres. The effect of these catalysts often goes through. Sintering back due to overheating, in which case the permeability of the catalyst is greatly reduced. In addition, they are clogged by macro-substances contained in the exhaust gas or deactivated by the gas only with difficulty the catalytic Can reach areas.

The invention is based on the object in exhaust systems for Internal combustion engines reduce the harmful effects of high temperatures on the catalytic converter and at the same time provide a catalytic converter device to create that quickly with a cold start Motor warms up. The latter condition is essential to prevent harmful products from occurring during the Warm-up of the engine to operating temperature.

The stated object is achieved essentially in that one with an inlet with an exhaust from the engine

409832/0626

at least one container with an outlet connected to it has a catalyst housing with catalyst material and a fastening by means of which the catalyst housing inside of the container between the inlet and the outlet and is kept at a distance from the container except in the area of the outlet.

In a further embodiment of the invention, the fastening can have a flange incorporated into the catalytic converter housing, through which it is connected directly or indirectly to the outlet.

The catalytic converter housing can provide a flow path for exhaust gases between the inlet and the outlet, including at least two separate permeable catalyst clusters,

This can cause the catalytic converter to accumulate in the catalytic converter housing lie in series in the flow path such that each catalyst accumulation nachexnander is acted upon by the entire exhaust gas flow taking place through the container.

Here, the catalyst housing can also have a long flow path for exhaust gases flowing through the container, the length of the flow path — it being at least twice the direct distance between the inlet and the outlet within the container.

409832/0626

An injection device can advantageously pass through the container extend in de.s catalyst housing, through the air or a other oxygen-containing flow medium into the through exhaust gas flowing into the container between the inlet and the outlet can be introduced.

If necessary, an injection device can be used here extend the container into the catalyst housing, through which air or other oxygen-containing flow medium into a can be introduced between the first and the second catalyst accumulation space.

The container can have at least one opening with a removable gas-tight closure as access to the catalyst housing or certain Have areas of the same.

The catalyst housing can advantageously be attached to one of the attachment be held at a distant point by an elastically loaded device.

Furthermore, a deformable or slidable housing support for the catalytic converter housing can be provided in such a way that the catalytic converter housing away from or towards the fastening device without undue stress. Such Expansions usually occur due to the thermal interplay on. .

409832/0626 "

The catalyst housing can also be a support for ceramic material have, is applied to the catalyst material.

Finally, the inlet to the container can expediently be one Form part of the exhaust pipe of the internal combustion engine or are connected to it.

By arranging the fastening device near the outlet it is located in a relatively cool area of the container; H. in an area where there are hot exhaust gases of the motor only arrive after they have passed through the container. In this way the material or materials are made of which the fastening device exists, exposed to loads occurring during operation at the lowest possible temperatures. If necessary, the fastening device can also be equipped with a cooling device.

Further features and advantages of the invention emerge from the claims and the following description of several in FIG Drawing of illustrated embodiments. In the drawing show:

Fig. 1, each one of five exemplary embodiments 3, 5, 7 and 9 of an exhaust system according to the invention in section

and

Fig. 2, each a section along the line A-A of Fig. 1,

k, 6, 8 and 10 3, 5, 7 and 9, respectively.

409832/0626

-S-

In the pig. 1 and 2 is a simple system with a container 10 made of corrosion-resistant steel, which has inlets 11, 12, 13 exhaust gases can be supplied. The inlets 11,12,13 ' are each provided with an end flange 11a, 12a and 13a, durcji that of the container 10 to an engine block for connecting the inlets 11, 12, 13 screwed to the exhaust ports of the engine block is.

The container 10 has an outlet 16 with an end flange 17 through which the container is screwed to an exhaust pipe can. ,

The container 10 surrounds a catalyst carrier or a catalyst housing 18, which is screwed to a surface 19 of the container by means of a Flange 20 is attached. The inside of the container 10 is except in the area of the gas inlets and the gas outlet covered with a thermal insulation material 21.

The housing 18 is at the top by means of a permeable cover 22 made of corrosion-resistant steel closed. At its bottom, the housing opens into an inner bore 23 of the flange 20.

The flanges 19 and 20 are screwed together gas-tight. In this way, the exhaust gas flowing into the container 10 through the inlets 11, 12, 13 can only flow out through the outlet 15 after it has flowed through the housing 18 via the cover 22. A flange 2k is attached inside the housing 18

welds, which carries a woven screen 25 made of corrosion-resistant steel. The sieve 25 serves to create a permeable aggregation or to support accumulation 26 of a catalyst granulate. The granules have an inert or chemically inert Ceramic component on which a catalyst, which is used in the present Case is suitable for accelerating the reduction of nitrogen oxides, is applied or deposited.

When the engine is running, the exhaust gases are inevitably from the engine through the inlets 11, 12, 13 down through the accumulation 26 and passed through the outlet 16 to the exhaust pipe. The proportionate small size of the housing 18 and the insulation created by the thermal insulation material 21 lead to a rapid Heating the catalyst pile when the engine is started, so that the accelerated by the catalyst Reduction conversions required optimal temperature of the Exhaust gas is reached quickly. The extensive surface area of the catalyst presented by the agglomeration causes a effective catalysis of the gas reactions on the flow path of the mass flows of the exhaust gas.

3 and M show a single unit with a ribbed or corrugated * support. Again, a container 30 is made of corrosion resistant Steel is provided to the exhaust gases through inlets 31,32,33 in the described in connection with Figs Way can be fed.

& 09837 / nfi? Fi

The container 30 is provided with an outlet 36 which is connected to a conventional exhaust pipe can be screwed on.

The container 30 surrounds a catalytic converter housing 38 which is screwed to a surface 39 by means of a flange 40. the The inside of the container 30 is covered with a thermal insulation material, except in the area of the exhaust gas inlets and the exhaust gas outlet 41 occupied.

The housing 38 is closed at the top by a pair of permeable lids 42a, 42b made of corrosion-resistant steel. The lids 42a, 42b are each arranged above a compartment 43,44 which Chambers for permeable agglomerations 45, 46 of a catalyst granulate represent. The accumulations 45, 46 each rest on a permeable plate 47 and 48, respectively. The plates 47 and 48 are in turn mounted on ribbed or corrugated supports 49.50 with a number of holes to create Outlet routes for the through the accumulation of catalyst granulate exhaust gases that have flowed through are provided. Such ribbed or corrugated supports are in the older British Patent application 61727/70 of the applicant described. The granules have an inert or chemically inert ceramic Component on which a catalyst, which in the present case is used to accelerate the reduction of nitrogen oxides is suitable, is applied.

- _ /, 09832/0626 ■

When the engine is running, the exhaust gases are inevitably led out of the engine through the inlets 31,32,33 down through the accumulations 45, ^ 6 and via the outlet % to the exhaust pipe. The relatively small size of the housing 38 and the insulation brought about by the insulating material 41 lead to a rapid heating of the catalyst accumulation when the engine is started, so that the optimum temperature of the exhaust gas required for the reduction conversions accelerated by the catalyst is quickly reached. The extended surface area or the amount of space of the catalyst presented by the accumulations causes an effective catalysis of the gas reactions on the flow path of the mass flows of the exhaust gas.

FIGS. 5 and 6 show a double system with a ribbed or corrugated support. Again, a container 50 is made of corrosion Resistant steel provided, the exhaust gases by means of inlets 51,52,53 in the described in connection with FIGS Way can be fed.

The container 50 is provided with an outlet 55 which is screwed by means of a flange 56 to a conventional exhaust pipe can be.

The 3ehälters 50 surrounds a catalyst housing 58, which is attached to a Flange 59 of the container is fastened by means of a screwed-on flange 60. The inside of the container 50 is provided with a Thermal insulation material 60a occupied. Nozzle 6l and cover 62 protrude into

409832/0626

removable closures. 63 in the wall of the container 5C. Within the housing 53 there are arranged shells 64, 65 of a woven screen made of corrosion-resistant steel, each of which rests on a permeable ribbed or corrugated support 66 and 67, respectively. The shells 6 ¹ 1.65 each support a permeable accumulation 68 or 69 of catalyst granules in connection with the pig. 1 and 2 described form.

Injection pipes 57 are arranged under the support 66. the Pipes 57 are provided with a series of openings through which air or some other oxygen-containing flow medium, which is introduced into the conduits 57 through means provided outside the container, into the downwardly from the Accumulation 68 can be injected into the accumulation 69 flowing exhaust gases.

When the Mofcor is running, the exhaust gases inevitably flow out of the Motor through inlets 51,52,53 into canister 50. The gases flow down through heaps 68,69 and over the outlet 55 out of the container.

In the present case, the granulate of the accumulation 68 contains a substance suitable for accelerating the reduction of nitrogen oxides ^! th catalyst. In contrast, the granule 69 includes the accumulation of a catalyst which is suitable for the acceleration of 'Oyxdationsumwandlungen z _s. B-. carbon · = monoxide into carbon dioxide and unve abrannt s hydrocarbon

409832/0628

- li -

fen in carbon dioxide and water through reactions between the corresponding Components of exhaust gases and air or other oxygen-containing medium passing through the pipes 57 is inserted into the housing. Instead, the clusters of both shells can optionally be made of the same catalyst material exist.

FIGS. 7 and 8 show a system with an extended flow path with a container 70 made of corrosion-resistant steel, the Exhaust gases. Through inlets 71 * 72.73 in the in connection with the Fig. 1 and 2 described manner can be supplied.

The container 70 has an outlet 75 with an end fan 76 -by connecting the container to a conventional exhaust pipe can be screwed on.

The container 70 encloses a catalyst housing 78, which is attached to is attached to a flange 79 of the container by means of a screwed flange 77. The inside of the container 70 is covered with a thermal insulation material 70a.

With a guide plate 81, the housing 78 delimits an extended flow path for the exhaust gas flowing from the inlets 71, 72, 73 to the outlet 75, including upper catalyst layers 82, 83 and lower catalyst layers 84, 85. The direction of the gas flow through these layers is indicated by arrows. Each layer 82 to 85 consists of stacks of ceramic

409832/0626

Mixer units that have a large number of horizontal channels with a triangular cross-section in the direction of gas flow (cf. Channel 88 in layer 83), on the walls of which a catalyst material is applied. In the case of the upper catalyst layers 82.83, the catalyst material has a nature that accelerates the reduction of nitrogen oxides. In case of lower layers 84,85, the catalyst material has a texture -auiV the the oxidation of. Carbon monoxide and / or accelerated unburned hydrocarbons. In the end spaces 8 ^ a, 85a injection pipes 87 are provided through the air or some other oxygen-containing flow medium introduced into the tubes 87 by means provided outside the container is introduced into which exhaust gases are blown can after these have flowed through the upper catalyst layers 82, 83, but before the gases through the lower catalyst layers 84.8S flow.

When the engine is running, the exhaust gases inevitably flow out of the engine through inlets 71, 72, 73 into the container. The gases flow into the upper catalyst layers 82, 83 in the direction illustrated by the arrows over those with the catalyst covered »or coated walls of the channels in the stacks of ceramic units. After passing through the top Layers 82,83, the exhaust gas mixes with the air blown through the pipes 87 and is then first down and then passed inward to through the lower catalyst layers 84.85 to flow in the direction shown. Thereupon

409832/0626

the exhaust gases are passed through the outlet 75 into the outside air.

9 and 10 show an exhaust system with elastic or f-edernder strain, which is largely based on the pig. I and 2 corresponds to the embodiment of the invention described. Parts 9 and 10, which correspond directly to those of FIGS. 1 and 2, have the same reference numerals with the addition an apostrophe. A further description of these parts is not given.

The arrangement or fastening of the catalytic converter housing 18 made by screwing the flange 20 'to the flange ^ ^{1 !} is supplemented by an elastically loaded arm 90.

The housing 18 'is provided with a permeable cover 91 which has uprights 92, 93 extending therefrom. The uprights 92, 93 are connected by a rod 9k on which the arm 90 acts. The arm 90 is welded to an axle 95 which is centered at one end in a bearing 96, which allows a limited axial play. At its other end, the axis 95 extends through the wall of the container 10 'via a stuffing box 97 with a heat-resistant packing 98 which is compressed by a shoulder washer 99. An arm 100 is pinned to the end of the axle 95 protruding from the stuffing box 97, the outer end of which is connected to one end of a tension spring 101, the other end to which is connected

409832/0626

is anchored in a suitable component.

The action of the spring 101 on the arm 90 causes elastic loading of the catalytic converter housing 18 ′ via the rod 9 * 1, the stands 92, 93 and the cover 91. This load causes a vibration damping of the floating or free end of the housing 18 ^! , ie the end facing away from the splash 20 ·. Such damping is important given the normal vibration conditions and the thermal interplay to which the housing 18 'is exposed when the vehicle is in operation. The manner of the exhaust system shown in FIGS. 9 and 10 corresponds to that described in connection with FIGS.

In connection with the above embodiments of the invention it should be noted that the catalyst housings 18,38,58,78, 18 · in their respective containers by a flange in the vicinity of the container outlet are attached. At this point the inner container is generally coolest, so the temperature, of the flanges under stress as little as possible is held.

The described arrangements make it possible that the top, facing away from the mounting flange portion of the respective housing can freely \ swim, that is, away from the mounting flange expand or can move towards the latter when the housing i engine vibrations and the interplay between the full operating temperature and the temperature cold, stopped engine.

409832/0626

Claims (12)

- 15 claims: 1.) Exhaust system for internal combustion engines, characterized in that that a container with an inlet connectable to an exhaust outlet of the engine and provided with an outlet rf " has at least one catalyst housing with catalyst material and a fastening by means of which the catalyst housing defined within the container between the inlet and the outlet and with the exception of the area of the outlet at a distance is held by the container. 2. Exhaust system according to claim 1, characterized in that the fastening included one in the catalyst housing Has flange through which it is connected directly or indirectly to the outlet. 3. exhaust system according to claim 1 or 2, characterized in that that the catalyst housing incorporating a flow path for exhaust gases between the inlet and the outlet at least two separate permeable catalyst clusters forms. 4. Exhaust system according to claim 3 * characterized in that that the catalyst accumulations in the catalyst housing in the flow path are in series such that each catalyst cluster is sequential from the total exhaust gas flow through the canister is applied. 409832/0626 5. Exhaust system according to claim 3 or ¹ I, characterized in that the catalyst housing forms a long flow path for exhaust gases flowing through the container, the length of the flow path being at least twice the direct distance between the inlet and the outlet within the container. 6. Exhaust system according to one of claims 1 to 5, characterized characterized in that a sparger extends through the container into the catalyst housing, through the air or another oxygen-containing flow medium into the exhaust gas flowing through the container between the inlet and the outlet is insertable. 7. Exhaust system according to one of claims 3 to 6, characterized in that an injection device extends through the container into the catalyst housing, through the air or another oxygen-containing flow medium in a
space lying between the first and the second catalyst accumulation can be introduced. 8. Exhaust system according to one of claims 1 to 7, characterized in that the container has at least one opening with a has removable gas-tight closure as access to the catalyst housing or certain areas of the same. 409832/0626 9. Exhaust system according to one of claims 1 to 8, characterized in that the catalyst housing on one of the Fixing remote point is held by an elastically loaded device. 10. Exhaust system according to one of claims 1 to 8, characterized in that a deformable or slidable housing support for the catalyst housing is provided in such a way that the catalyst housing away from the fastening device or can be stretched towards this without undue stress. 11. Exhaust system according to one of claims 1 to 10, characterized characterized in that the catalyst housing has a support for ceramic material, applied to the catalyst material is. 12. Exhaust system according to one of the claims 1 to 11, thereby characterized in that the inlet to the container forms part of or is connected to the exhaust pipe of the internal combustion engine is. 409332/0626