DE2260685A1 - AFTERBURNER FOR COMBUSTION MACHINERY - Google Patents

Description

DR.-ING. G. CLOTHING

Γ "Κ

My sign

A 793-lo / Le

Please repeat in the answer

L J. ■

899 Lindau (Lake Constance)

Your reference Your message from Rennerle 10 · P.O. Box 3160

December 11, 1972

Reference:

Dr.h.c. Dipl.Ing.Paul August, Barcelona 6 / Spain

Afterburner for internal combustion engines

The invention relates to an afterburner for internal combustion engines with at least two catalysts for the reduction of NO, GO and CH.

To the future regulations for low-toxic automotive engines to meet, it is necessary / with catalysts and reactors the No, CO and CH proportions contained in the exhaust gas so to reduce that only traces are left. Therefor

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Telephone: Telegraph: Speaking time: Lindau (08382) 6917 054374 by appointment Kfz .: Fu 2581897

Bank accounts: Postal check account: Bayer. Staatsbank Lindau (B) No. 1562 Munich 29525 Bayer. Mortgage and Exchange Bank Lindau (B) No. 278920

there are two different options.

1. The mixture formation for the engine is proportionate regulated in bold, so that little no is produced. These NO shares are in a first, the Engine downstream catalytic converter, reduced. In a second catalyst, the high CO and CH proportions, whereby air is blown in in front of the catalyst.

2. The mixture composition for the engine becomes Regulated to approx. A ο, 98. Downstream of the engine becomes just a catalyst that reduces NO and oxidizes CO and CH makes. It is not necessary to inject air for this catalytic converter.

3. Because of the better effectiveness, monolith bodies become used as catalysts.

Execution to 1. has two disadvantages. On the one hand, the engine uses more fuel than for that Power output is necessary. On the other hand, the second catalyst must be relatively large in order for it to be the larger CO and CH shares are actually almost completely burned. This execution required not only a lot of space, but also a lot of expensive catalytic material.

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The version for 2 .. also has disadvantages. Once is the control of the mixture formation complicated, expensive and is also prone to failure. On the other hand, a catalyst does all three Is designed to reduce toxic gases and works without excess air, a shorter service life.

The version to 3 has the disadvantage that this monolith body because of their smaller temperature coefficient become loose in their envelope when heated and rapidly due to mechanical vibrations be destroyed. Namely, the cladding is sheet steel, and this sheet steel has a lot larger temperature coefficient than this monolith body.

These and other disadvantages are intended to be remedied by the invention. When running after the Invention, the exhaust gases are first fed into a larger catalytic converter, which reduces the NO content, however, some of the CO and CH components are also post-incinerated. The mixture formation setting is around Ao.92 - o.98. This regulation The mixture with a greater tolerance and a slightly fatter area is significant, simpler and more can be done from inexpensive carburetors. Regulation according to Λ ο, 98 is only possible with injection

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make facilities that are significantly more expensive.

The driving behavior of an automobile ^ is with the something richer mixture regulation also better. Before the exhaust gas enters the first catalytic converter This flows through a mixing device, which preferably consists of steel flakes.

After the exhaust gases exit the first catalytic converter, air is supplied to the exhaust gases. The exhaust fumes now in a second part of the afterburner, which for reasons of space is usually narrower than the first part.

The second part of the afterburner consists of a combination of catalytic material for the oxidation of CO and CH and mixing devices which again preferably consist of high-temperature steel chips.

An embodiment of the invention is shown in the drawing. Do this from the drawing and the description of further features of the invention.

The exhaust gases flow in at input 1 and first enter the mixing device 2. They then enter the

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first catalytic converter 3 a. You flow through it and exit into room 4. In this space there is an air supply device 5 _f which allows the combustion air to flow evenly into the exhaust gas through openings 6. This exhaust gas, which is now provided with additional air, flows through the afterburner 7, which is provided with mixing device o and catalytic converters 9, and leaves it at the J output Io.

If the catalytic converters consist of monolith bodies / these bodies are opposed to those made of steel chips Mixing devices pressed so that they sit tight at any temperature. This prevents loosely seated catalyst bodies from settling smashed. The pressing can be done by means of a bolt 11 running through the middle with a clamping nut 12, can be made. At the top and bottom of this package there are perforated plates 13, which the have the same expansion as the wall of the afterburner 7 and thus no laterally when heated Gap arises.

The catalyst 3 is also attached in the same way, it being sufficient that only at one end the resilient mixing devices are located.

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The head end of this bolt 14 is preferably designed as a cone 15, the exhaust gases from the Keep something away from the middle of the catalyst.

The mode of action of this afterburner is as follows: At 1, the exhaust gases enter and are through the Cone 15 rejected from the center, so that they are evenly distributed around. You flow through the mixing device 2 which ensures that the distribution of the exhaust gases is further improved. The entry of the exhaust gases into the catalyst 3 now takes place fairly evenly over the entire area Area. This means that stronger heat fields, e.g. in the center of the catalytic converter, cannot arise. Such Heat centers that otherwise develop quickly have often led to the rapid destruction of the catalyst, wai is avoided in the practice of this invention.

Since the mixture composition is a little richer than Λ 1 the reduction of NO is very intensive and the required limit values of 0.4 g / mile are reached fallen below.

However, since the mixture composition is not very rich, one is also formed in the same catalyst 3 Oxidation of CO and CH, which is not just a decrease

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this brings proportions, but also the catalyst at the desired high temperature holds, which in turn has advantages for the reduction of NO.

In the catalyst. 3 now enter the following room 4 Exhaust gases which only have traces of NO and which already contain very little CO and CH components. This exhaust gas is provided with combustion air relatively evenly, which via the pipe 5 with his Openings 6 is blown. Because the exhaust gas contains only a little CO and CH, it is absolutely necessary that it flows through mixing devices in which the few CO and CH components are brought together with oxygen particles. In the subsequent catalysts, which are preferably are arranged several times, and between which there are further mixing devices, the Remains of CO and CH are totally burned afterwards.

The mixing devices located between the catalytic converters, also take over the temperature of the catalytic converters and thus also act as Heat reactors for additional combustion.

The service life of catalytic converters is essentially dependent on three factors. These are:

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1. Vibration-free storage of the monolites in the afterburner. This is according to the invention achieved that the catalysts at one or both ends against the resilient steel filings the mixing device are pressed. The lateral guidance takes place through perforated sheets two ends that are the same size as the jacket of the afterburner.

2. Even distribution of the exhaust gases as they flow through the catalytic converter. The one in front of the catalyst arranged mixing devices not only bring better combustion through better mixing, but they distribute the exhaust gas evenly over the entire entrance of the same.

3. Lower amounts of NO, CO and CH in the exhaust gas for the afterburning. The selected mixture composition of approx. 0.92 to 0.98 brings less NO shares as Al and still relatively little CO and CH. In the first catalytic converter 3, approx. half of the CO and CH are burned afterwards, so that in the afterburner 7 one with relatively weftig Catalyst material gets by because, among other things, the mixing devices also act as heat reactors and also burn some of the CO and CH. The overall arrangement of heat reactors with mixing devices as well as catalysts embedded therein relieves the catalysts in such a way that the

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Service life of the same is almost doubled »

For reasons of space, the afterburner 7 will be made smaller in diameter than the catalyst 3. Since it can be longer, there is the added advantage that time and way gained for the residual combustion of GO and CH becomes what is necessary to actually burn the residues afterwards.

The entire afterburner is heated to the outside * insulated »This insulation also has a noise-insulating effect. Combined with the packages of mixing devices and catalytic converters that have a sound-absorbing effect, it will be unnecessary to use a first silencer » You will get by with the usual second silencer »

During a cold start, the air supply to the overall afterburner is supplied upstream of the afterburner until the combustion temperature of the first catalytic converter is reached. Air is preferably fed into the exhaust manifold in this part, in the vicinity of the exhaust valves. A lesser proportion of air is further fed before the total afterburner namely the amount necessary for AEIE exhaust gas composition corresponds to what a combustion of a fuel * "

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Air mixture of A * ο, 95 corresponds. The control this amount of air takes place e.g. by means of a Droftsel "flap, which is controlled depending on the carburettor.

In summary, it can be stated that the task is solved with a practically 100% detoxification of the exhaust gas to significantly increase the life of the catalytic converter.

This is achieved by connecting the distributor device 15, the mixing device 2, the catalytic converter 3 for NO, the mixture in space 4, the air injection at 5 and the mixing devices 8, which are arranged in front of and behind the catalytic converters 9, in series. This arrangement according to the invention achieves NO reduction in the first catalytic converter, there is no excess of oxygen and partial afterburning of CO and CH. In the afterburner that closes, there is excess oxygen, where the remaining portion of CO and CH is burned.

Claims

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Claims (13)

Claims lJ afterburner for internal combustion engines with at least two catalytic converters for the reduction or combustion of NO, CO and CH, characterized in that mixing devices are assigned to the catalytic converters. 2. Afterburner for internal combustion engines, thereby characterized in that the exhaust gas composition is an exhaust gas prior to entering the afterburner corresponds to what corresponds to a fuel-air mixture of Λ o.92 to ο.98. 3. Afterburner according to claim 2, characterized characterized in that this exhaust gas composition by appropriate mixture formation in the carburetor or an injector. 4. Afterburner according to claim 1, characterized characterized in that deviations of this mixture composition below \ o.92 by metered Air supply before the afterburner is brought to the desired exhaust gas composition. -12- 0 9826/0460 5. Afterburner according to claim 1, characterized characterized in that the main part or all of the air supply in the case of a cold start before the afterburner is supplied and after reaching the burning temperature of the catalyst 3, the main portion or the total amount of air after the catalytic converter 3 is fed to the afterburner. 6. Afterburner according to claim 1-5, characterized in that the mixing devices consist of highly heat-resistant steel chips e.g. V2A steel. 7. Afterburner according to claim 1-6, characterized characterized in that the mixing devices are made resilient with steel chips and these be assembled with the catalyst bodies to form a package under pressure. 8. Afterburner according to claim 7, characterized marked that at the beginning and end of such a package there are perforated disks, which correspond to the inner diameter of the afterburner jacket. 9. afterburner according to claim 1, characterized in that before the first Catalyst or the mixing unit arranged in front of it 409826/0460 -13- direction a cone is assigned to the exhaust gas flow away from the center of the catalyst. 10. Afterburner according to claim 1, characterized marked that the oxidation afterburner is smaller in diameter than the reduction catalyst .. 11. Afterburner according to claim 1, characterized characterized in that the oxidation afterburner consists of steel chips in the catalyst particles are distributed. 12. Afterburner according to claim!, Characterized gekennze rejects that the overall afterburner is insulated from the outside. 13. Afterburner according to claim 1 - 12, characterized in that the overall afterburner is ei chnet replaced the!. silencer. 409826/0 460 Blank page