DE2225715A1 - Purification of exhaust gases from internal combustion engines - Google Patents

Description

DR. BSRG 0Ii ³ L ₈ -ING. STAPF 1 O 1 Γ Π <ί π

ZZZb I p

PATENT LAWYERS 8 MUNICH 8O. MAUERKIRCHERSTR. 45

Dr. Berg Dipl.-Ing. Stapf, 8 MOnchen 80, Mauerkirdierstraße 45

Your reference Your letter Our reference Date 2 ßi M <i \

Attorney file 22 507

Esso Research and Engineering Company linden / USA

"Cleaning the exhaust gases from internal combustion engines"

The present invention relates to the purification of exhaust gases from internal combustion engines.

It has already been proposed to use the exhaust gas from an internal combustion engine to pass through an exhaust gas purification reaction vessel in the exhaust system, and it has been further proposed that that such an exhaust gas reaction vessel as a packing

-2- 209851/0765

should have a bed of catalytic material that causes or promotes chemical reactions in order to reduce the concentration of potential air pollution, ■ such as the Oxides of nitrogen, to decrease. In the previously proposed exhaust system, which had such reaction vessels, the exhaust gas flow passed through the reaction vessel was essentially always in the axial direction to the exhaust gas line performed.

According to the present invention, the concentration of pollutants in the exhaust gas is reduced by that the exhaust gas is passed into a reaction vessel containing a catalyst which is essentially perpendicular to the Axial direction of at least part of the exhaust system is directed, and that the exhaust gas is an annular bed can run through from catalytic material. It has been found that by this procedure are essentially the same or greater reductions in pollution concentration compared to the reductions that occurred after Prior art can be obtained, but that the pressure damping by the reaction vessel of the invention is compared to the reaction vessels according to the prior art, and that the time which the reaction vessel requires around its effective working temperature after cold conditions to achieve is reduced. '

The present invention relates to a reaction vessel for 209851/0765

Purification of exhaust gas from an internal combustion engine, characterized in that it has an inner perforated. Wall _f which is connected at one end to the exhaust pipe of the engine and the other end is closed, an outer perforated wall which surrounds the inner wall and is arranged at a distance from this, an annular space between the perforated walls, the exhaust ^ Contains purification catalyst and has a casing spaced from and surrounding the outer perforated wall to form an annular space for receiving the exhaust gas directed radially outward through the catalyst-containing space, the casing having an exhaust port and is connected to the exhaust pipe or exhaust «

In a preferred embodiment of the invention, the Catalyst an alloy that contains nickel and one or more metals from copper, earring and / or iron.

Some of the alloys that are particularly preferred include:

(a) ITichrome (registered trademark) - approximate composition: 60 $ Ni, 16 $ Gr, 24 $ Pe

(b) Inconel (registered trademark) - approximate composition: 73 $ Ni, 16 $ Or, 8 $ Pe

(c) Type 304 stainless steel - approximate composition: 10 '$ IJi, 19 $ Cr and 70 $ Pe

(d) Copper-nickel alloy - about $ 30 Ni, $ 70 Gu

(e) Monel (registered trademark) - approximate composition! $ 66 Ni, $ 31.5 Cu, $ 1.4 Pe, $ 1 Mn.

The particularly preferred alloy is Monel.

Whichever of the aforementioned alloys (a) - (e) is also used, the problem always arises that, after a reaction vessel in which such alloys are built has, has 15,000 to 18,000 km of machine running behind him, in the case of the exhaust gas is formed, the alloy, whether it is in the form of porous sintered metal or it is a number of discrete bodies (e.g. rings, spheres, saddle fillers, blunt-ended paraboloids or tubes) that add to this tends to under the influence of, inter alia, the high temperature (preferably at least 340 ° and generally 370-400 °) of the Alloy is subject to agglomerating when its cleaning action is exercised. This agglomeration tends to the To increase the resistance of the reactor bed to the exhaust gas flow and leads to a simultaneous reduction in the Efficiency and net power of the engine from which the reaction vessel receives the exhaust gas.

In a preferred embodiment of the invention, the Alloy takes the form of discrete bodies mixed with discrete bodies made of a refractory and / or ceramic Material are formed. For example, the alloy can

-5-2098Β1 / Π765

the shape of saddles or blunt-ended paraboloids and the refractory and / or ceramic material the shape of Have tubes or rings. It has been found that a mixture of discrete alloy bodies and discrete refractories and / or ceramic bodies (at least one economically long working period) is free of any "significant" Tendency of the alloy to agglomerate while hot Comparative tests with the sole use of the alloy body the adverse effects of agglomeration can already be determined after about 200 hours of use was «

The refractory and / or ceramic bodies can contain an oxidation or reduction catalyst of any known type Kind to increase or modify the generally reducing catalytic nature of the alloy.

It is preferred that the discrete bodies of alloy and ceramic or refractory material be approximately one another should have the same dimensions.

For most purposes it should be the radial thickness of the annular Catalyst bed be approximately 40 to 55 mm.

In a structurally preferred form of the reaction vessel of the invention, the inner and outer are perforated Walls received at their ends in grooves that are in the

-6-

209851/0765

admitted opposite end walls of the reaction vessel are, with the end walls connected to each other by bolts or similar devices, and the surrounding or enclosing wall (casing) with the end walls, gas-tight connected »the inner, outer End and casing walls can be made of mild steel or stainless steel =

The invention also includes an exhaust system for an internal combustion engine which has a reaction vessel as described above, a conduit one end of which is provided to receive the exhaust gas from at least one cylinder of the engine, and the other end of which is connected to one end of the inner perforated wall of the Reaction vessel is connected, an exhaust pipe which is connected to one end of the enclosing wall of the reaction vessel around the exhaust port, and a muffler which is connected to the other end of the exhaust pipe having. It is preferred that the length of the conduit is selected so that the exhaust gas entering into the reaction vessel during the normal working, _e d _e h after the machine has reached the intended operating conditions, a temperature of at least 54-0. C, and preferred temperatures in the range of 370-400 ° 0.

The invention further provides the combination of an internal combustion engine with an exhaust system, as described in the previous paragraph, wherein one end of the line ωLt is the Lotor for receiving the exhaust gas from at least one Z _t y- 209851/0765 _, _

~ 7 -

linder of the engine is connected _o

Without thereby limiting the invention, an embodiment will now be described in more detail with reference to the accompanying ones Drawings described in which:

Figure 1 is a schematic representation of a gasoline internal combustion engine and its exhaust system,

Figure 2 shows a cross section of an exhaust gas purification reaction vessel containing a catalyst and into the exhaust system of Figure 1 is installed, and

Figure 3 shows one end of the reaction vessel, as shown in Figure 2, here.

In FIG. 1, the engine 10 has a cylinder block 11 in which four cylinders 12 are provided. A carburetor 13 is attached to the inlet manifold 14, and the exhaust gases exit the cylinder block 11 via an exhaust manifold 15, which is connected via a flange connection 16 to an inlet line 17 ″ of a catalytic exhaust gas reaction vessel 18 is. This in turn is connected to the exhaust pipe 120 and a silencer 121 via a flange connection 19 connected, from which the cleaned exhaust gases are discharged via an exhaust pipe 122. It should be noted that the arrangement of the parts only serves to explain the invention, and that changes to the arrangement explained can be made without deviating from the invention, so that, for example, the so-called Zufüh-709851/0765 -8th-

approximately line 17 curved in the conventional manner or in separate sections can be designed to allow removal from the engine or machine in which it is installed, to enable.

Referring to Figures 2 and 3, the flange 16 has Openings 16a for bolts (not shown) and forms a whole with the conduit 17 and an end wall 27 of the reaction vessel 18. End wall 27 has bolt holes 29 near its edge and the other end wall 28 is similar Provided with holes 29 in the manner. Between the end walls 27, 28 there is an inner wall 20 with a perforation. rations 21, an outer Y / andung 22 with perforations 23 and a bed 24 of exhaust gas purifying material in the annular space between walls 20 and 22. The ends of the Walls 20 and 22 are received in grooves formed in the opposite surfaces of end walls 27 and 28 are let in. A jacket housing 25 'which is attached at a distance from the outer perforated wall 22 and this surrounds, delimits an annular space for receiving the purified gas and an opening 25a in the housing 25 is to discharge the purified gas from the reaction vessel

18 via a collection outlet 26 and the Flane clienverbungen

19 planned

The housing 25 has flange ends with bolt holes that with the bolt holes 29 in the end walls 27 and: 't> übercrci.r.-;.: tii! '' ".- n. on the outside of each flange end of the

709851/0765 _ ₀ _

housing 25 is an everted nose 31 with a rebate 32 at the edge of the corresponding end wall 27, 28 coincides, creating a seal between the ring of the bolt holes 29 and the seam 32 is formed to avoid the escape of gas. It's for the professional it is clear that the reaction vessel 18 is strong, but easily dismantled when the bolts passed through the holes 29 (not shown) can be removed from end walls 27 and 28.

In one embodiment of the invention that is successful in a lord Capri 2600 was used, 2 reaction vessels 18 (one for each exhaust manifold) were used, with each had the following dimensions

Diameter of the inner wall 20 50 mm

Diameter of the outer wall 22 150 mm

Diameter of the holes 21, 23 4 mm

Case diameter 25 170 mm

Axial length of the bed 24 50 mm

The openings 21, 23 were uniformly distributed over the corresponding walls 20 and 22 and took about 50 ⁰ Jo a surface thereof.

Each bed 24 of the reaction vessel was filled with Lionel saddles, the saddle fill being approximately $ 25

ρ of the bed volume and an active surface of 8 cm

-10-v? 0 9R51 / 0765

per cm * of bed formed. The size of the saddle bodies was 6 to 7 mm (or approximately), maximum dimension. The catalyst in the ring bed was activated by passing an exhaust gas stream through the reaction vessel for 20-24 hours.

The reaction vessel was chosen for its effectiveness in reducing KO _V emissions in exhaust gas in the Ford

JL

Capri 2600 tested, this one with an air / fuel ratio from about 13.5s1 worked and the subsequent ones Results obtained:

California Test NO ^ Emissions

ppm g / km

in front of the reaction vessel 667 1.15

after the reaction vessel 58 0.10

Federal 1975 Test

after reaction vessel - 0.12

The test results show that substantial benefits in reducing Ν0 _χ contamination can be achieved using the reaction vessel of the invention »

It was a comparative test between a reaction vessel carried out with axial flow direction and the reaction vessel with radial flow direction of this invention, wpbei the amount of Monel saddle bodies and their volume distribution in each bed was essentially the same as the amount and volume distribution of the reaction vessel, which in terms of

-11-

209851/0765

its effect on the ITO-y emission was examined. The following results were obtained with a 'Ford Oapri 2600:

Type of reaction vessel

Warm-up time, sec. (California test)

Increase in back pressure

if the process conditions remain the same

40 km / h 60 »
80 »
90 "

radial flow guide

about 110

10
20th
35
40

axial current conduction

about 200

2.5

90

110

Ea it is clear that the design of the reaction vessel satisfactory contact between the exhaust gas and the Monel saddles enables a NOy emission control to be carried out with a relatively low back pressure.

The previous investigations were carried out without ceramic or refractory material in the reaction vessel.

In another study, a slightly larger overall size reaction vessel was built into the single _{exhaust system (i.e.,} a system with an exhaust manifold) of a Fiat 124. The annular catalyst bed was with a mixture of Monel saddles, the main dimensions of which were now 6-7 and with; ceramic tubes of the kind they are for

-12- ? Π Π R b 1 / V \ 7 6 h

electrical insulators are used, which had a main dimension of 5-7 μ, filled » Dm- · ' annular catalytic bed had a radial thickness of 4> 58 cm. At a speed of 100 km / h, the pressure damping through the reaction vessel was only 10 cm H _? 0; this is very little pressure attenuation, considering that the total pressure attenuation through the muffler and exhaust pipe alone is 47 cm HpO at 100 km / h and that for catalytic beds 6.35 cm with axial flow (the minimum dimension described above for emission regulation) a pressure attenuation of 15 cm was obtained under similar working conditions.

Despite the very advantageous reduced pressure damping by the reaction vessel of the invention, it was found that the amount of KOy emission in the exhaust gas is considerably greater than The result of the good contact between the catalytic converter and the exhaust gas was reduced. Studies after a katal ^ Sator activation of over 3000 km of engine power according to the "California Hot cycle procedure "a reduction in the nitrogen oxide content of the exhaust gas of about 80 ^. Exactly the The l \ O content of the exhaust gas was reduced from 913 ppm to 182 ppr.i, and at higher speeds, the nitrogen oxide content of the exhaust gas was reduced by as much as 85-957 degrees.

It can be seen from the preceding examples that the invention offers significant advantages, namely air pollution

-13-

? Π 9 RBI / Π 7 6 h öRl & HAL INSPECTED

by reducing emissions from automobiles without significantly affecting engine performance »

Claims ;. -H-

209851/0765

Claims (2)

-H- Patent to Proverbs: 1. ) Reaction vessel for cleaning exhaust gas from an internal combustion engine, characterized in that it has an inner perforated wall, one end of which is provided for connection to the exhaust pipe of the engine, and the other end is closed, an outer perforated wall which the inner wall surrounds and is spaced from it, an annular space between the perforated walls containing the exhaust gas purification catalyst, and a Ummantelcwandung which is spaced from and surrounds the outer perforated wall, thereby creating an annular space for receiving the exhaust gas, the radii: ·.], is passed outward through the catalyst-containing space, the casing having an exhaust pipe and being intended for connection to the exhaust pipe » 2. Reaction vessel according to claim 1, characterized in that the catalyst is an alloy containing nickel with copper, chromium and / or iron. 3 ο reaction vessel according to claim 2, characterized in that the alloy contains approximately 66, j lii, 31.5 $ Cu together with other alloy-forming constituents ₀ -15- 4. Reaction vessel according to claim 2 or 3, characterized in that the alloy is used in the form of discrete bodies mixed with discrete bodies made of refractory and / or ceramic material _o 5. reaction vessel 'according to claim 4, characterized in that the alloy is in the form of Saddle bodies or of blunt "ending Para" boloid hats « 6 ο reaction vessel according to claim 4 or 5, characterized in that the refractory or ceramic material has the shape of tubes or rings _o 7 ο reaction vessel according to one of claims 4 to 6, characterized in that the ceramic or refractory bodies form the support for an oxidation catalyst. B. Re action ge barrel according to one of claims 1 "to 7, characterized in that the catalyst bed in the annular space, has a thickness of 40" to 55 mm ₀ 9. Reaction vessel according to one of the preceding claims characterized, that the inner and the outer perforated wall are received at their ends in grooves made on the. opposite end walls of the reaction vessel that the end walls are connected to each other by bolts, and that the surrounding Wall is connected to the end walls in a gas-tight manner. 10. Reaction vessel according to claim 9, characterized that the inner, outer end walls and shell walls made of mild steel or stainless Steel are formed. 11. Exhaust system for an internal combustion engine, thereby characterized in that there is a reaction vessel according to one of claims 1 to 10, a line, one of which End is provided for receiving the exhaust gas from at least one cylinder of the engine, and the other end with the one end of the inner perforated wall of the reaction vessel is connected, an exhaust pipe which is connected to one end of the jacket wall of the reaction vessel around the exhaust gas opening is connected, 'and has a muffler that is connected to the the other end of the exhaust pipe is connected " 12. Exhaust system according to claim 11 characterized in that the length of the line is οο selected so that the entering into the reactor exhaust gas during the normal working process, a tempering has bur of at least 34O ⁰ C. 13. Combination of an internal combustion engine with an exhaust system according to claim 11 or 12, characterized in that - -17- 209851/0765 indicates that one end of the line is marked with is connected to the engine to absorb the exhaust gas from at least one cylinder of the engine " 14. Vehicle, provided it contains the combination of claim 13 . 2 Π 9 8 5 1 / f.) 7 6 5 ie Blank page