FIELD OF INVENTION
The present invention is towards elimination or reducing particulate matter of exhaust from combustion engines.
The invention relates to Particulate Combustion Catalyst (PCC), particulate filter, and exhaust gas clean-up
system. The invention more particularly relates to a composition and device designed to remove particulate
5 matter or soot from the exhaust gas of diesel engines, Gasoline Direct Injection (GDI) engines etc. The
present invention also relates to methods for manufacturing the said device.
BACKGROUND OF THE INVENTION:
The elimination or reduction of particulate matter emancipating from the exhaust of combustion engines during
1 o its operation is always desired. Commonly known wall-flow particulate filters (DPF) can remove over 95% of
the particulate matter (PM) from diesel engine exhausts. Some filters are designed for single-use, intended
for disposal and replacement once full of accumulated soot. Others are designed to burn off the
accumulated particulate either passively through the use of a catalyst or by an active means such as a fuel
burner which heats the filter to soot combustion temperatures.
15 Filters require more maintenance than catalytic converters. Continuous built up of trapped particulate matter
blocks the filter medium thereby leading to increase in the back pressure across such devices and adversely
impacting engine performance and consequently emission compliance. The soot gets collected inside
porous metallic medium and on the metallic screen due to principles of inertial impact. There is a continuous
need to develop efficient particulate removal and the present ·rnvention provides for the same. The present
20 invention provides for a d~vice which produces less back pressure than a conventional DPF with more cross
flows and utilization of the substrate.
SUMMARY OF INVENTION
The inventors have designed a PCC that overcomes risks of failure due to continuous built up of trapped
particulate matter by allowing an alternate open flow path in case of soot saturation, thereby confining
25 backpressure under permissible limits. Simulation based approach and field testing was used to study,
design and develop new cross flow structures by evaluating the pressure drop and collection efficiency. The
structure was optimized for efficient soot collection without blockage of the main flow paths.
The invention discloses a three ·dimensional device for the catalytic treatment of exhaust gases of
automotive vehicles comprising of a substrate f<:>rmed by connecting a plurality of honeycomb/substrate
30 members, each having a structure in which a number of cells are arranged in parallel or in series or parallely
arranged in series with respect to each another.
2
Another aspect of the present invention is a substrate formed by a unique combination of Porous Metallic
Medium (PMM) and metallic screen with different shape of its openings, and different mesh numbers with or
without or corrugated or micro corrugated material to form a three dimensional (30) structure.
Another aspect of the present invention is to combine a corrugated or micro corrugated PMM with the
5 corrugated or micro corrugated metallic screen with different shape of its openings, and different mesh
numbers with or without or corrugated or micro corrugated material to form a three dimensional (30)
structure.
Another aspect of the present invention is to combine a corrugated or micro corrugated PMM with the noncorrugated
metallic screen with different shape of its openings, and different mesh numbers with or without
10 or corrugated or micro corrugated material to form a three dimensional (30) structure.
Yet another aspect of the present invention is a non-corrugated PMM can be uniquely combined with the
corrugated or micro corrugated metallic screen with different shape of its openings and different mesh
numbers with or without or corrugated or micro corrugated material to form a three dimensional (30)
structure.
15 Another aspect of the present invention is that every cell inside the substrate, is composed of metallic screen
with differe~t shape of its openings and different mesh numbers and/or corrugated or micro corrugated
notched metallic material and I or inorganic material and PMM as its walls.
Yet another aspect of the present invention is that CPCCZ is coated with a unique washcoat material that is
capable ofcontinuously producing in-situ nitrogen dioxide, which is essential for continuous oxidation of trapped
20 soot particles leading to increase PM reduction efficiency .
• BRIEF DESCRIPTION OF DRAWINGS
The features of the present invention will become apparent from the following description of the preferred
embodiments given in conjunction with the accompanying drawings, in which:
25 Figure 1.1: PCCz combination of PMM & metallic screen - Schematic depiction
Figure 1.2: Improved mass and heat transfer in turbulent type corrugated channel
Figure 1.3: Straight channel corrugated substrate structure.
Figure 1.4: Straight channel corrugated porous metallic media with micro corrugated I notched metallic; foil.
Figure 1.5: Straight channel corrugated foil with micro corrugation
30 Figure 1.6: Angle corrugated foil with higher cpsi & with micro corrugation
3
Figure 1.7: Angle corrugated foil with lower cpsi and with micro corrugation
Figure 1 .8: Angle corrugated flat foil $Ubstrate and Angle + micro corrugated foil substrate
·Figure 1 .9: Angle + micro corrugated foil and Straight channel micro corrugated foil
Figure 1.10: Turbulent type 'corrugated porous metallic medium
5 Figure 1.11: Angle corrugated porous metallic medium
Figure 1.12: Flat I un-corrugated porous metallic medium
Figure 1.13: Metallic screen with single-knit structure and square mesh opening
Figure 1.14: Metallic screen with multi-knit structure and square mesh opening
· Figure 1.15: Structure of rectangular screen
1 o Figure 1.16: Structure of square screen
Figure 2: Examples of the different shapes of Particulate Combustion Catalyst and Coated Particulate
Combustion Catalyst
Figure 3.1 - 3.13: L'lP variations of selected samples having different combinations and with corrugation.
Figure 4: Mass emission data of selected samples having different combinations and with corrugation.
15 Figure 5: Outline of Scheme 1 Process fiow for Particulate Combustion Catalyst (PCC) and Coated Particulate
Combustion Catalyst (CPCC);
Figure 6: Outline of Scheme 2 of Process fiow for Particulate Combustion Catalyst (PCC) and Coated Particulate
Combustion Catalyst (CPCC);
Figure 7: Outline of Scheme 3 Process fiow for Particulate Combustion Catalyst (PCC) and Coated Particulate
20 Combustion Catalyst (CPCC)
Figure 8: Outline of Process flow for preparation of washcoat for Coated Particulate Combustion Catalyst
(CPCC)
Figures 9 - 22: Comparative Laboratory Simulation Plots of oxidation reactions of Carbon monoxide oxidation,
Propylene oxidation & Nitrogen dioxide formation with temperature for different combinations of PCC2 and
25 CPCC2 (henceforth called as catalytic activity), tested under different operating conditions.
Figures 9a & 9b compare the CO, HC conversion-% and N02 formation % as a function of temperature with
Space Velocity 30.000 h-1 for one and two layer VF-structures with flat porous metallic medium (PMM) and angle
corrugated metallic screen with rectangular mesh with PGM-Ioadings 1, 2, 5, 10 and 20 g/fP.
4
Figure 10 compares the CO, HC conversion-% and N02 formation %as a function of temperature with Space
Velocity 30.000 h-1 for on~ layer VF-structure with flat porous metallic medium (PMM) and angle corrugated
metallic screen with rectangular mesh with PGM-Ioading 1 glft3 and for one layer Prior art VX-structure with
PGM-Ioading 20 glft3.
5 Figures 11a & 11b compare the CO, HC conversion-% and N02 formation% as a function of temperature with
Space Velocity 30.000 and 60.000 h-1 for one layer VF-structures with fiat porous metallic medium (PMM) and
angle corrugated metallic screen with rectangular mesh with PGM-Ioadings 1 and 5 glft3.
Figures 12a & 12b compare the CO, HC conversion-% and N02 formation Ofo,as a function of temperature with
Space Velocity 60.000 h-1 for one and two layer VF- with flat porous metallic medium (PMM) and angle
1 o corrugated metallic screen with re~tangular mesh with PGM-Ioadings 1, 5, 10 and 20 glft3.
Figures 13a & 13b compare the CO, HC conversion-% and N.02 formation% as a function of temperature with
Space Velocity 30.000 h-1 for uncoated structures with three different type of corrugations for porous metallic
medium (PMM) with flat I uncorrugated foil (UF) or with micro corrugated I notched foil (MF).
Figures 14a & 14b compare the CO, HC conversion-% and N02 formation% as a function of temperature with
15 Space Velocity 30.000 h·1 for one layer structures with three different type of corrugations for porous metallic
medium (PMM) with fiat I uncorrugated foil (UF) or with micro corrugated I notched foil (MF). PGM-Ioading is the
same 1 glft3 in all cases.
Figures 15a & 15b compare the CO, HC conversion-% and N02 formation% as a function of temperature with
Space Velocity 30,000 h-1 for one layer structures with different type of corrugations for porous metallic medium
20 (PMM) with flat I uncorrugated foil (UF) or with Micro corrugated I notched foil (MF). PGM-Ioading is the same 5
glft3 in all cases.
Figures 16a & 16b compare the CO, HC conversion-% and N02 formation% as a function of temperature with
Space Velocity 30,000 and 60.000 h-1 for one layer structures with angle type of corrugation of porous metallic
medium (PMM) with fiat I uncorrugated foil (UF) or with Micro corrugated I notched foil (MF). PGM-Ioading is 10
25 glft3.
Figures 17a & 17b compare the CO, HC conversion-% and N02 formation% as a function of temperature with
Space Velocity 60.000 h-1 for one layer structures with with three different type of corrugations of porous metallic
medium (PMM) with fiat I uncorrugated foil (UF) or with Micro corrugated I notched foil (MF). PGM-Ioading is 10
glft3.
30 Figures 18a & 18b compare the CO, HC conversion-% and N02 formation% as a function of temperature with
Space Velocity 30.000 h-1 for one layer Prior art VX-structure with 330 cpsi, corrugated metallic screen having a
PGM-Ioading of 1, 5, and 10 glft3.
5
Figure 19 compares the CO, HC conversion-% and N02 formation% as a function of temperature with Space
Velocity 30.000 and 60.000 h-1 for one layer structures with the three different type of corrugations for foil (CF)
with flat porous metallic medium (PMM). PGM-Ioading is the same 1 glft3 in all cases.
Figure 20 compares the CO, HC conversion-% and N02 formation% as a function of temperature with Space
5 Velocity 30.000 and 60.000 h-1 for one layer structures with the three different type of corrugations for foil (CF)
with flat porous metallic medium (~MM). PGM-Ioading is the same 5 glft3 in all cases.
Figure 21 compares CO, HC conversion-% and N02 formation % as a function of temperature with Space
Velocity 30.000 and 60.000 h-1 for one layer structures with the three different type of corrugations for foil (CF)
with flat porous metallic medium (PMM). PGM-Ioading is the same 10 g/ft3 in all cases.
1 o Figures 22a & 22b compare the CO, HC conversion-% and N02 formation % as a function of temperature with
Space Velocity 30.000 and 60.000 h·1 for one layer structures with two different type of corrugations for porous
metallic medium (PMM) with flat I uncorrugated foil (UF) or with micro corrugated I notched foil (MF). PGMIoading
is the same 1 g/ft3 in all cases.
Figures 23.1 & 23.2 describe Soot loa?ing behavior as a function of distance covered CPCC2 samples having a
15 different structural combination and different corrugations.
DETAILED DESCRIPTION OF THE INVENTION
Other objects and aspects of the invention will become apparent from the following description of the
embodiments with reference to the accompanying drawings, which is set forth hereinafter. The embodiments
20 of the present invention can be modified variously. Thus, the scope of the present invention should be
construed not limited to the embodiments to be described herein. The embodiments are provided to better
explain the present invention to thos~ of ordinary skill in the art. Further, the elements and areas of the
drawings are drawn roughly only, and the scope of the present invention is not limited to the relative sizes,
.shapes and-gaps in the drawings.
25 The below list provides. the full forms of abbreviations whenever used in the specification:
Abbreviation
PCC Particulate Combustion Catalyst
PCCz Particulate Combustion Catalyst
DOC Diesel Oxidation Catalyst
CPCC Coated Particulate Combustion Catalyst
PCCz Coated Particulate Combustion Catalyst
PMM Porous Metallic Medium
MF Micro-corrugated Foil
uc Uncoated
6
c Coated
cc Closely Coupled
UF Under Floor
The device disclosed in the present invention is for catalytic treatment of exhaust gases which is comprised
of a substrate formed by connecting a plurality of individual members wherein said individual member comprises
of a plurality of cells. The individual member can have a honeycomb body. The plurality of cells are arranged in
5 parallel or in series or in parallel series with respect to each another.
10
The invention discloses a substrate formed by a unique combination of Porous Metallic Medium (PMM) and
metallic screen with different shape of its openings, and different mesh numbers with or without or
corrugated or micro corrugated material to form a three dimensional (30) structure. The invention allows for
substantial trapping of particulate matter emancipating from an engine.
A corrugated or micro corrugated PMM is combined with the corrugated or micro corrugated metallic
screen with different shape of its openings and different mesh numbers and/or corrugated or micro
corrugated notched metallic foil and/or inorganic fibrous woven matrix material to arrive at the three
. dimensional (30) structure.
Alternative embodiment of the invention is to combine a corrugated or micro corrugated PMM with the
15 non-corrugated metallic screen with different shape of its openings, preferably rectangular and different
mesh numbers and/or corrugated or micro corrugated notche.d metallic foil and/or inorganic fibrous woven
·matrix material to arrive at this three dimensional (30) structure. The PMM could be fleece.
Alternatively, a non-corrugated PMM can be uniquely combined with the corrugated or micro corrugated
metallic screen with different shape of its openings, preferably rectangular and different mesh numbers
20 and/or corrugated or micro corrugated notched metallic foil and/or inorganic fibrous woven matrix material to
arrive at this three dimensional (30) structure.
The invention further discloses that every cell inside the substrate, is composed of metallic screen with
different shape of its openings, preferably rectangular and different mesh numbers and/or corrugated or
micro corrugated notched metallic foil and I or inorganic fibrous woven matrix material and PMM as its walls.
25 The cell density is preferred to be in the range from 20 to 1300 cells per square inch (cpsi), preferably from 50-
600 cpsi. The inorganic fibrous woven matrix material has a fiber thickness in the range of 5 to 22 micrometers.
The inorganic fibrous woven matrix material thickness is from 0.5 to 100 millimeter in a single layer, more
preferably 0.5-10 millimeter and porosity is in the range of 70 to 95 %.The PMM has a preferred porosity in the
range of 70- 95% and used in varying thickness of 0.1 mm to 1 mm.
7
5
10
15
20
.
The members of the substrate are combined in unique ways to form different geometries such as circular,
. oval, square, rectangular, doughnut shaped, banana shaped, layered doughnut etc., each with or without a
bypass and for different sizes and can either be solid fitted or can be partially open in radial and I or axial
direction to give a variety of flow patterns.
The mesh numbers of the metallic screen of the substrate are preferred in the range of 120 - 20 meshes per
· inch, more preferably 90 -30 meshes per inch. Metallic screen wire diameter is in the range of 0.08 - 0.3mm,
preferably between 0.1 - 0.2 mm. whereas metallic foil has a thickness in the range of 20 - 110 micrometers,
· preferably between 40 - 80 micrometers. The height of micro-corrugation is in the range of 0.01 - 0.5 mm,
preferably between 0.02- 0.2 mm.
The substrate of the invention exhibits high thermal and mechanical durability at all engine loads.
The invention discloses that it is possible to produce PCCZ /CPCCZ with cell densities ranging from 20 to
1300 cells per square inch (cpsi), preferably between 50 and 600 cpsi, with or without micro corrugation. The
corrugation is angular and corrugation angle is in the range of 10 to 60 degrees, preferably in the range of 32-
40 degrees. The corrugation can also be straight or turbulent.
CPCC2 which is the coated PCC2 is capable of oxidizing the trapped soot particles leading to increase PM
reduction efficiency. It is further disclosed that CPCC2 & PCCZ is capable of oxidizing the trapped soot particles
with a volume substantially lower than that of prior art. A much lower back pressure is seen when compared to
the existing devices when the substrate of the present invention is used in a device to increase the PM reduction
efficiency.
The invention discloses that CPCC2 is coated with a washcoat material that is capable of continuously
producing in-situ nitrogen dioxide, which is essential for continuous oxidation of trapped soot particles leading to
increase PM reduction efficiency. The invention discloses the unique washcoat material and method of preparing
the same.
The unique coating of a washcoat is disclosed by the inventors. The washcoat comprises of a combination
25 of catalytically inactive material and catalytically active material. The washcoat is to be applied before or after the
substrate is formed.
The catalytically inactive material of the washcoat includes a combination of a variety of oxides, nitrates, and
hydroxides of aluminum, silicon, titanium, zirconium, hafnium, calcium, barium, strontium and rare earth metal
oxides. The catalytically inactive material has a specific surface area ranging between 100 to 260 sqm per g.
30 The washcoat comprises of fine particles having a median particle size distribution ranging between 0.5 - 3.5
microns.
The washcoat allows substantial in-situ generation of nitrogen dioxide in the range of 20% to 50% by
volume, which continuously allows efficient oxidation of soot accumulated inside the body of the honeycomb
8
structure during the operation of the engine. The substrate provides same or lower backpressure than that
before washcoat coating. It was surprisingly found that the washcoat coating provides catalytic performance at
much lower volumes leading to cost and pollution reduction.
The catalytically active material used in the washcoat comprises but is not limited to a combination of a
5 variety of salts of platinum, palladium, rhodium, ruthenium, osmium and iridium, preferably platinum, palladium
and rhodium. The catalytically active material is contained in the honeycomb body of the substrate preferably in
the range of 0.5 to 30 g/cubic feet, more preferably from 1 -10 g/cubic feet.
The coating of the washcoat has a thickness in the range of 0.5 to 10 micrometers, preferably from 1 - 5
micrometers. The elements can be incorporated in pre-washcoated honeycomb body. The elements can be
10 incorporated into the washcoat material directly, before carrying out the coating.
15
The washcoat is designed to have a high degree of adhesion to both the PMM and metallic screen as well
as metallic foil and inorganic material and its combinations thereof. The washcoat exhibits high thermal and
mechanical durability and resists poisoning due to sulfur present in the automotive exhaust gas, when the engine
is in operation.
The substrate of the invention' offers uniform flow distribution and has interacting three dimensional channel
network, which allows quick dissipation of heat energy released during regeneration of such devices. There is
improved heat and mass transfer efficiency leading to optimum internal diffusional and axial flows.
The substrate has interacting channels which effectively decelerates sticky and/or wet & dry particles alike,
from the engine exhaust, on their surfaces that eventually are trapped inside the PMM and /or metallic mesh with
20 different shape of its openings, preferably rectangular and different mesh numbers and/or within the inorganic
fibrous woven matrix. The capturing of solid particles happens predominantly by impinging the collected particles
from the engine exhaust, upon the interposed deflecting surface
In another embodiment of the invention the PMM and the metallic screen are also individually coated with a
combination of catalytically inactive material and catalytically active material, before forming them into a
25 substrate
The different features of the invention are further described by way of non-limiting examples to better
understand the invention:
Figure 2.1 depicts schematically the PCCZ combination of PMM & metallic screen of the present invention.
Figure 1.2: explains the improved mass and heat transfer in turbulent type corrugated channel. Figure 1.3- 1.16
30 reveal the different embodiments of the substrate structure and combinations including straight/corrugated/micro
corrugated I notched metallic foil/ angle corrugation/Turbulent/porous /Flat fun-corrugated/Metallic
screen/rectangular screen/square screen
9
Figure 2 depicts examples of the different shapes of Particulate Combustion Catalyst and Coated Particulate
Combustion Catalyst
Evaluation of backpressure:
5 From Figure 3.1, it can be seen that substrate formed by the combination of flat PMM & angle corrugated 330
cpsi screen clearly exhibits highest .D.P (1448). The second highest is for flat PMM & angle corrugated 330 cpsi
(1401/1).
This is followed by a substrate formed by the combination of flat PMM and 330 angle corrugated screen with
having a lower volume (1461 ).
1 o Both the prior art structures.(1394/3 & 1405) show a little lower .D.P with 33 screen corrugation and with square &
rectangular mesh.
From Figure 3.2, it can be seen that the substrate formed by the combination of flat PMM and 330 cpsi angular
corrugated screen (1448) exhibits the highest .D.P, while the combination of flat PMM and 400 cpsi angular
corrugated screen (1461) exhibits the lowest .D.P.
15 An another combination of prior art substrate structure (1405 +1407) and combination of flat PMM and 330 cpsi
angle corrugated (1401 /1) lies in between.
From Figure 3.3, it can be seen that the substrate formed by the combination of 330 cpsi angle corrugated PMM
and 330 cpsi angle corrugated screen gives the highest .D.P (1436/1 ). The second prior art substrate with 330
'cpsi angle corrugated screen (1394/3) gives the same .D.P with both square and rectangular mesh (1405).
20 The lowest DP is exhibited' by the substrate formed by the combination of 200 cpsi turbulent type corrugated
screen and. grooved PMM (1444)
From Figure 3.4, it can be seen that the prior art containing 330 cpsi corrugated screen evidently gives highest
. .D.P (1394/3). It is also observed that the structure formed by the combination of 100 cpsi angle corrugated PMM
and flat screen (1401/4), exhibits a high DP, than the structure formed by the combination of flat PMM and 100
• 25 cpsi angle corrugated screen (1401/3).
From Figure 3.5, it can be seen that the prior art substrate (1583/1) with 400 cpsi screen gives the highest delta
P and 1582/1with 33p cpsi screen has the lowest delta P. Both flat PMM substrates, 1584/1 & 1585/1 with 330 &
400 cpsi respectively are in betw~en.
From Figure 3.6, it can be seen that the prior art substrate with 400 cpsi screen (1581/1) exhibits the highest .D.P,
30 The substrate formed by the combination of flat PMM and straight channel 300 cpsi corrugated screen gives
lowest .D.P. The soot loading efficiency the prior art substrate with 330 cpsi screen (1580/1) lies between.
10
From Figure 3.7, it can be seen that substrate formed by the combination of flat PMM and straight channel 300
or 400 cpsi corrugated foil (1590/1 & 1591/1) exhibits a lower .0.P and a combination of flat PMM and straight
channel 500 cpsi corrugated foil (1592/1 ), a combination of flat PMM and turbulent channel 350 cpsi corrugated
foil (1597/1) exhibits the highest .0.P values.
5 From Figure 3.8, it can be seen that substrate formed by the combination of flat PMM and straight channel100
cpsi corrugated foil (1588/1) exhibits a lower .0.P and a combination of flat PMM and turbulent type channel 200
cpsi corrugated foil (1596/1) exhibits the highest .0.P values . .0.P measured for a combination of flat PMM and
.turbulent channel120 cpsi corrugated foil ( 1595/1) and a combination of flat PMM and straight channel 200 cpsi
corrugated foil are about the same and lies in between.
1 o Figure 3.9, describes the .0.P behaviour of two distinct substrate structure types, formed by the (1) combination of
flat PMM and straight channel300 cpsi corrugated foil (1590/1_uc & 1590/1_c) and (2) as well as that formed by
another combination of flat PMM and turbulent type channel350 cpsi corrugated foil (1597/1_uc & 1597/1_c).
· In this plot, the combination of flat PMM and turbulent type corrugation exhibits higher DP. In the both structures,
coating does not increase .0.P.
15 From Figure 3.1 0, it can be seen that substrate formed by the combination of flat PMM with straight channel1 00
cpsi corrugated foil (1588/1_uc & 1588/1_c) exhibits much lower .0.P than a combination of flat PMM with
turbulent type channel120 cpsi corrugated foil (1595/1_uc & 1595/1_c).
In the both structures, coating does not increase ~P.
From Figure 3.11, it can be seef) that layered doughnut type substrate structures formed by the combination of
20 flat PMM and angle corrugated screen with 263 cpsi ( 167 4/1) and another combination of flat inorganic fibrous
woven matrix with angle corrugated 263 cpsi screen gives the lowest ~p value.
The double crossing layered doughnut structure (1675) exhibits a clearly higher ~P compared to the single
crossing layered doughnut structure (167 4/1 ).
The prior art substrate structure with 292 cpsi angular corrugation (1687) & a combination of flat PMM with angle
25 corrugated 263 cpsi screen (1676) exhibits the highest ~P.
From Figure 3.12, it can be seen that layered doughnut type substrate structures formed by the combination of
flatPMM with angle corrugated 263 cpsi screen (1669) exhibits the lowest DP.
Another combination of flat PMM with angular corrugation, 263 cpsi (1669) screen exhibits the highest DP and
prior art substrate (1682) with 263 cpsi angle corrugated screen lies in between.
30 From Figure 3.13, it can be seen that layered doughnut type substrate structures formed by the combination of
flat PMM with angle corrugated 263 cpsi screen ( 1673) exhibits the lowest ~p.
II
. Another combination of fiat PMM with angular corrugation, 263 cpsi (1659) & 303 cpsi (1660) corrugated screen
substrates exhibits about the same and the highest LlP.
Performance evaluation studies on chassis dynamometer (mass emission):
The catalytic activity in terms of mass emission of various combination of CPCC2 was evaluated on chassis
5 dynamometer. The samples under study were assembled into the exhaust assembly of the test vehicle, which
was then driven to on a driving cycle simulating a typical Indian city driving pattern. During this operation, major
pollutants consisting of carbon monoxide, hydrocarbon, oxides of nitrogen & particulate matter, emancipating
from the engine, are continuously monitored and measured as grams of these pollutants emitted per kilometre
travelled by the test vehicle
I o Figure 4 ·compares the mass emission data of the prior art substrate structure, with the substrate ( CPCCZ)
formed by the various combinations of fiat PMM & angle corrugated screen at different levels of volume viz.
1.817 L (prior art) & 0.374L (current invention) respectively.
The data shows that in spite of having a lower volume (4.85 times) than the prior art substrate, the substrate
formed by the various combinati~ns of flat PMM & angle corrugated screen exhibits lower mass emissions,
15 specifically for particulate matter.
Performance evaluation studies on simulated gas test bench:
All the catalytic activity studies described in the examples were carried out on simulated exhaust gas test bench.
The typical inlet gas composition gas comprises of (1) CO: 1000-1500 PMM, propylene propane: 500-800
ppm, 02: 12 -14 %, NO: 500- 800 ppm, 6 -10 % C02, 7 -12% steam & balance nitrogen.
20 Regulated fiow of preheated mixture of these gases are fed into a reactor containing the sample under
evaluation. Space velocities are controlled by regulating the fiow of the gas mixture entering the reactor. The
output gases from the reactor are analyzed by a state of the art multi gas analyzer.
The output of the evaluation are the plots of oxidation reactions of Carbon monoxide oxidation, Propylene
oxidation & Nitrogen dioxide formation with temperature.
25 PCCZ and CPccz formed by unique combinations of corrugated or micro corrugated PMM and/or corrugated or
micro corrugated metallic screen with different shape of its openings, preferably rectangular and different mesh
numbers and/or corrugated or micro corrugated notched metallic foil and/or inorganic fibrous woven matrix
material, with different preCious metal loadings, varied washcoat layers, were evaluated at different space
velocities.
30 PCC2 was formed by combining a flat PMM with an angle corrugated metallic screen with rectangular mesh. The
so formed Pccz was converted to CPccz by coating the former with a combination of catalytically inactive
12
material, in such a manner to achieve a coating thickness of 2 micrometers. Four samples of this said CPccz
were then each coated with 1 g/cft, 5g/cft, 10g/cft & 20 g/cft of PGM.
The above substrate was dried, calcined & evaluated for its catalytic activity. Figure 9 compares catalytic activity,
specifically the light-off temperature curves of the CPCCZ at space velocities of 30,000 /h.
5 The corrugation angle of 34° was selected for all the angle corrugated samples combinations.
From Figure 9a, it can be seen that at a space velocity of 30.000 h-1 SV, CPCCZ having 5 g/ft3 of PGM, exhibits
the best CO and HC light-off curves for one layer VF structure (VFO, VF1 ,VF5, VF1 0, VF20. VF5) also exhibits
the highest N02 formation among all the evaluated series.
From Figure 9b, it can be seen that at a space velocity of 60.000 h-1 SV, CPCCZ having 20 g/ft3 of PGM, exhibits
1 o the best light-off curves for two layer VF structure (VFO, VF1 ,VF5, VF1 0, VF20. VF5), specifically in the case of
N02 formation of 38% at the temperature of 350 oc.
VF20 on two layer washcoat gives the best efficiencies and with 30.000 h-1 SV since the whole washcoat layer is
available for the catalytic reaction.
VF5 on one layer and VF20 on two layer have the best in situ N02 formations.
15 From the cost point of view the best solution is VF5 in one layer.
Blank (uncoated and PGM-free) samples, PCCZ show only minor conversions.
From Figure 10, it can be seen that, CPccz having 5 g/ft3 of PGM in one layer VF structure (VF1 ), exhibits better
light-off behaviour than that having 20 g/ft3 of PGM in prior art VX honeycomb structure (VX20).
This implies a reduction of 95% in PGM-cost.
20 VF1 gives also better in-situ N02-formation efficiency.
From Figures 11a & 11b, it can be seen that, at a space velocity of 30,000 /h, CPccz having 5 g/ft3 of PGM
exhibits the best light-off behaviour (VF5, 30K).
However at a space velocity of 60.000 /h CPCCZ having PGM-Ioading of 1 g/ft3 is about at the same level with
this one layer VF-structure (VF5, 60K).
25 Cost wise VF5 is 80 %cheaper solutlon in PGM-cost.
'From Figure 12a, it can be seen that CPccz having PGM-Ioading of 1 g/ft3 gives the best light-off behaviour for
one layer VF-structure.
13
It is also observed that CPccz having PGM-Ioading of 20 g/ft3 exhibits a very poor light-off behaviour for one
layer VF-structure, which can be explained by the fact that that PGM-density is too high for this one layer VFstructure.
From Figure 12b it can be seen that, at a space velocity of 60,000 /h, VF10 (CPCCZ having PGM-Ioading of 10
5 gfft3) on the 2 layer VF structure gives the best efficiencies because PGM-density is better than that with PGMIoading
20 g/ft3, when the whole washcoat layer in not in use for catalytic activity.
Cost wise best solution is VF1 in one layer.
Figure 13 shows the light-off curves for samples P-1661 to P1666 as following blank/uncoated structures
(PCCZ): Turbulent type of corrugated PMM with UF as flat (P-1661) and with MF as Micro corrugated (P-1662);
10 Straight channel corrugated PMM with UF as flat (P-1663) and with MF as Micro corrugated (P-1664); Angle
corrugated PMM with UF as flat (P-1665) and with MF as Micro corrugated (P-1666).
From Figure 13 it can be clearly seen that, without coating or PGM-Ioading, structures with a combination of
different corrugated PMM and flat (uncorrugated) or micro corrugated foil doesn't give any remarkable
conversions.
15 Figure 14a shows the light-off curves for samples P-1661 to P1666 as following coated structures (CPCCZ):
Turbulent tyP.e of corrugated PMM with UF as flat (P-1661) and with MF as Micro corrugated (P-1662); Straight
. .
channel corrugated PMM with UF as flat (P-1663) and with MF as Micro corrugated (P-1664 ); Angle corrugated
PMMwith UF as flat (P-1665) and with MF as Micro corrugated (P-1666).
In all. the three types of corrugation, it is observed that the catalyst efficiency is superior for micro corrugated foil
20 structures as compared to flat uncorrugated foil structures as evaluated at a space velocity of 30.000 h-1 and with
aPGM-Ioading 1 g/ft3. The light off curves show the advantage of micro corrugation, especially at temperatures
greater than 300°C, where the mass and heat transfer phenomena begins to control catalytic reactions. With the
• use of micro corrugated substrate, the laminal type of flow at the catalyst surface (boundary layer) can be
broken, thereby enhancing the mass transfer between the exhaust gas and the wall, which results in improved
25 . catalytic efficiency.
Figure 14b shows the light-off curves for samples for only Straight channel corrugated PMM with UF as flat (P-
1663) and with MF as micro corrugated (P-1664). It is clear that the catalyst efficiency is better for micro
corrugated foil structure co(Tlpared to flat uncorrugated foil structures evaluated at a space velocity of 30.000 h-1
SV and with PGM-Ioading 1 g/fP. The results show how micro corrugation helps especially at over 300 oc
30 temperatures where mass and heat transfer start to control catalytic reactions.
Figure 15a shows the light-off curves for samples for Straight channel corrugated PMM with UF as flat (P-1663)
and with· MF as Micro corrugated (P-1664 ). It is evident that the catalyst efficiency is superior for Micro
14
corrugated foil structure compared to fiat uncorrugated foil structure evaluated at 30.000 h-1 SV and with PGMIoading
of 5 g/fP.
Figure 15a shows the light-off curves for CPCC2 samples with Straight channel corrugated PMM with UF as fiat
'(P-1663) and with MF as Micro corrugated (P-1664). Angle corrugated PMM with UF as flat (P-1665) and with
5 MF as Micro corrugated (P71666). The catalyst efficiencies are found better for micro corrugated foil structures
compared to flat uncorrugated foil structures evaluated at 30.000 h·1 SV and with PGM-Ioading of 1 g/fP .
. Figure 16a shows the light-off curves for CPCC2 samples with Angle corrugated PMM with UF as flat (P-1665)
and with MF as Micro corrugated P-1666 evaluated at a space velocity of 30.000 h-1 SV and 60.000 h·1 SV is
· shown in Figure 16b. Results show that when the space velocity increases from 30.000h·1 to 60.000 h·1 the light-
1 o . offs move to higher temperature regime but at both the space velocities, the micro corrugated foil structures
. show better catalytic efficiencies compared to fiat uncorrugated foil structures with PGM-Ioading of 10 g/fP.
· It is also observed that N02 formation is at good level at the space velocity of 30,000 for (P-1666) with MF and
with a PGM-Ioading 10 g/fP. This kind of in situ N02 formation gives good basis to reach efficient soot
regeneration for diesel exhaust PM starting from about temperatures of 230°C.
15 Figure 17a shows the light-off curves for CPCC2 samples with Straight channel corrugated PMM with UF as fiat
(P-1663) and with MF as Micro corrugated (P-1664).
From this CPCCZ with Straight channel corrugation test case, it can be seen that the catalyst CO and HC
efficiency are slightly better and N02 clearly better for fiat uncorrugated foil structure UF compared to Micro
corrugated foil structure MF at a space velocity 9f 60,000 h·1 SV and a PGM-Ioading 10 g/fP.
20 Figure 17b shows the light-off curves for CPCCZ samples with Turbulent type of corrugated PMM with UF as flat
(P-1661) and with MF as Micro corrugated (P-1662); Angle corrugated PMM with UF as flat (P-1665) and with
MF as Micro corrugated (P-1666).
Results show that the micro corrugated foil structures MF show better efficiencies compared to flat uncorrugated
foil structures UF in both turbulent type and angle corrugated PMM with PGM-Ioading 10 g/ft3 and at a space
25 velocity of 60.000 h·1• Also it can be seen that the angle corrugated PMM with MF gives the best efficiencies in
all studied respects (CO, HC and N02).
Figure 18a shows the light-off curves for CPCCZ samples with both VX and VL prior art structures with PGMIoadings
of 1, 5 and 10 g/ft3 with one layer coating.
Figure 18a shows the light-off curves for CPCC2 samples VX1 & VL 10. As can be seen, the catalytic
30 performance of the former is far poorer as compared to that for VL 10, which is the best. Both the samples have
one layer coating.
15
In both cases VX and VL the effiGiencies improves as PGM-Ioading increases. VL 10 and VL5 are the best in this
set of comparison.
Figure 19 shows the light-off curves for CPCC2 samples with Straight channel corrugated foil CF with fiat PMM
(P-1700) Turbulent type corrugated foil CF with fiat PMM (P-1701); Angle corrugated foil CF with flat PMM (P-
5 1702).
It· is obvi0us from all the three corrugation cases, that the catalyst efficiency is better at a space velocity of
30.000 h·1 SV than with that of 60.000 h·1 and with a PGM-Ioading 1 g/fP.
From the different corrugations examined, the turbulent channel corrugation exhibits superior catalytic efficiency,
while the Straight channel corrugations is the second best, followed by the Angle corrugation, which is
1 o comparatively inferior or in this set. of comparison.
N02 formation % are rather low for all cases, because higher PGM-Ioadings are needed to give higher efficiency
in this respect. Turbulent corrugation P-1701 gives N02 formation-%.
Figure 20 shows the light-off curves for CPCC2 samples with Straight channel corrugated foil CF with flat PMM
(P-1700); Turbulent type corrugated foil CF with flat PMM (P-1701 ); Angle corrugated foil CF with fiat PMM (P-
15 1702).
From all the three corrugation cases it is observed that the catalyst efficiency is better at a space velocity of
30,000 h·1 SV than with 60.000 h·1 and with a PGM-Ioading 5 g/ft3.
Among the three different corrugations evaluated, the turbulent channel corrugation gives the best efficiencies,
Straight channel corrugations is the second best and Angle corrugation the worst in this comparison with 30.000
20 h·1 SV. However with 60.000 h·1 SV Straight channel structure is the best.
N02 formation % are still rather low for all cases, because higher PGM-Ioadings are needed to give higher
efficiency in this respect. Turbulent corrugation P-1701 gives the N02 formation-%.
Figure 21 shows the light-off curves for CPccz samples with Straight channel corrugated foil CF with fiat PMM
(P-1700); Turbulent type corrugated foil CF with flat PMM (P-1701); Angle corrugated foil CF with fiat PMM (P-
25 1702).
From all the three corrugation cases we can see that the catalyst efficiency is better at a space velocity 30,000 h·
1 SV than with that of 60.000 h·1 and with a PGM-Ioading 10 g/fP.
Among the three different corrugations evaluated, the Straight channel corrugation gives the best efficiencies,
Turbulent channel corrugations is the second best and Angle corrugation the worst in this comparison with
30 30.000 h·1 SV. However at a space velocity of 60.000 h·1, turbulent channel structure P·1701 exhibits the best
performance.
16
N02 formation at 28 % max and Straight channel corrugation is the best with PGM-Ioading 10 g!ft3. For straight
channel corrugation P-1700 N02 formation improves when PGM-Ioading increases from 1 to 5 and 10 g/ft3 but
turbulent corrugation P-1701 gives best N02 formation-% with PGM-Ioading 5 g/ft3 and is at the same level than
straight channel corrugation P-1700 with 10 g/ft3 1oading.
5 Figure 22a & 22b shows the light-off curves for CPCC2 samples with Straight channel corrugated PMM with UF
as flat (P-1663) and with MF as Micro corrugated (P-1664); Angle corrugated PMM with UF as flat (P-1665) and
with MF as Micro corrugated (P-1666) at space velocities of 30,000 h-1 & 60,000 h-1 respectively
Among both the types of corrugation, it can be seen that the catalyst efficiency is better for micro corrugated foil
structures compared to flat uncorrugated foil structures with both SVs and PGM-Ioading 1 g/ft3.
I o The light off curves show the advantage of micro corrugation, especially at temperatures greater than 300°C,
where the mass and heat transfer phenomena typically starts to control catalytic reactions.
In the case of Angle corrugated PMM with MF (P-1666) the effect of efficiency improvement is prominent with a
space velocity 60.000 h-1 than compared to 30.000 h-1. With the use of micro corrugated substrate, the laminal
type of flow at the catalyst surface (boundary layer) can be broken, thereby enhancing the mass transfer
15 between the exhaust gas and the wall, which results in improved catalytic efficiency.
Soot loading studies
Soot loading studies were carried out on some of the selected samples, as described in figures 23.1 & 23.2. The
said samples were fitted into the exhaust assembly of the test yehicle, which was then driven to a distance of
200 km on a driving cycle simulating a typical Indian city driving pattern. During this operation, soot emancipating
20 from the engine, enters the sample structure and gets collected therein. This process is termed as soot loading.
Figure 23.1 shows that, for catalysts placed in the close coupled position, flat PMM and angle corrugated screen
yields the highest soot collection efficiency up to 150 Km. After that, the prior art substrate 1394/2 collects the
most.
.The under fl0or (UF) catalyst with prior art substrate.1395/2 exhibits lowest soot loadings.
25 Figure 23.2 shows that, fiCJt PMM and straight channel corrugation screen (1586/1) shows the highest soot
collection efficiency, followed by the substrate formed by the combination of Flat PMM and turbulent type of
corrugation foil (1597/1). The next best soot loading efficiency is exhibited by the substrate formed by the
combination of flat PMM and straight channel corrugated foil with 400 cpsi (1591 /1 ).
· The lowest soot loading efficiency is displayed by the substrate formed by the combination of flat PMM and
30 • straight channel corrugated foil with 200 cpsi.
·Results of the experiments conducted on some samples are presented in below tables:
I 7
Table 1
Reference Figure 3.1
Sample Sample No Structure Dimensions Corrugation Coating/ Mesh
Code De,scription D*L(mm) (cpsi) PGM(g/cft) shape
VX10 1394/3 Prior Art D63L152 330 Prior arU10 Square
VX10 1405 Prior Art D63L152 330 Prior arU10 Square
1401/1 Flat PMM +Angle
VF Corrugated Screen D63L152 330 0 Square
1448 Flat PMM + Angle
VF Corrugated Screen D63L152 330 0 Square
1461 Flat PMM + Angle
VF Corrugated Screen D63L120 400 0 Square
Table 2
Reference Figure 3.2
Sample Sample
Structure Description Dimensions Corrugation Coating/
Code No D*L(mm) (cpsi) PGM(g/cft) Mesh shape
1405 Prior art substrate
VX10 structure D63L152 330 Prior arU10 Rectangular
1407 Rrior art substrate
VX10 structure D75L304 330 Prior arU10 Square
VF 140111 Flat PMM + Angle 330 0 Corrugated Screen D63L152 Square
1448 Flat PMM +Angle
330 0 VF • Corrugated Screen D63L152 Square
VF 1461 CFolartr uPgMatMed + S Acnregelen 400 0 D63L120 Square
Table 3
Reference Figure 3.3
Sample Sample No Structure Dimensions Corrugation Coating I PGM Mesh shape code description D*L(mm) (cpsi) (g/ft3)
VX10 1394/3
Prior art substrate
D63L152 330 Prior arU10 Square; 1394/3 =
structure 1404
VX10 1405 Prior art substrate D63L152 330 Prior arU10
structure Rectangular
Angle corrugated
1436/1 PMM +Angle D63L150 330 0 Rectangular
corrugated Screen
Turbulent type
1444 corrugated screen D63L150 200 0 Turbulent type structure + grooved PMM '
Table 4
Reference Figure 3.4
Sample • Sample Structure description Dimensions Corrugation Coating I Mesh shape code No D*L(mm) (cpsi) PGM (g/ft3)
-~-" ....
VX10 1394/3 Prior art substrate D63L152 330 Prior arU10 Square structure
18
VF 1401/3_uc Flat PMM +Angle
Corrugated Screen D63L152 100 0 Rectangular
VFO 1401/3_c Flat PMM + Angle D63L152 100 Current Rectangular Corruqated Screen invention/ 0
1401/4_uc Angle corrugated PMM
+ Flat Screen D63L152 100 0 Rectangular
1401/4_c Angle corrugated PMM
+ Flat Screen D63L152 100 invCeunrtrieonnt/ 0 Rectangular
19
Table 5
Reference Figure 3.5
Sample Sample Structure Dimensions Corrugation Coating I code No description D*L (mm) (cpsi) PGM (glft3) Mesh shape
VLO 158211
Prior art substrate
D63L150 330
current
structure invention I 0 Rectangular
VLO 158311 Prior art substrate D63L150 400 current Rectangular
structure invention I 0
VFO 158411
Flat PMM +Angle
D63L150 330
current
Corrugated Screen invention I 0 Rectangular
VFO 158511 Flat PMM + Angle D63L150 400 current Rectangular Corrugated Screen invention I 0
Table 6
Reference Figure 3.6
Sample Sample Structure Dimensions Corrugation Coating I code No description D*L (mm) (cpsi) PGM (glft3) Mesh shape
vxo 158011 Priors atrrut cstuubres trate D63L 150 330 invceunrtrioenn t I 0 Rectangular
vxo 158111
Prior art substrate
D63L150 400 current
structure invention I 0 Rectangular
Flat PMM + Straight
VFO 158611 Channel Corrugated D63L150 300 current invention I 0 . Rectangular
Screen
Table 7
Reference Fi.gure 3.7
Sample Sample Structure description Dimensions Corrugation Coating I PGM (glft3) code No D*L (mm) .(cpsi)
P1700 159011
Flat PMM + Straight
Channel Corrugated Foil D63L150 300 current invention I 0
P1700 159111 Flat PMM + Straight
Channel Corrugated Foil D63L150 400 current invention I 0
P1700 159211 Flat PMM + Straight D63L150 500 current invention I 0 Channel Corrugated Foil
P1701 159711 FTlyapt eP MCoMr ru+g Tauterbdu Fleonilt D63L150 350 current invention I 0
Table 8
Reference Figure 3.8
Sample Sample Structure Dimensions Corrugation Coating I PGM (g/ft3) code No description D*L (mm) (cpsi)
Flat PMM + Straight
P1700 158811 Channel Corrugated D63L150 100 current invention I 0
Foil
Flat PMM + Straight
P1700 158911 Channel Corrugated D63L150 200 current invention I 0
Foil
20
Flat PMM +
P1701 159511 Turbulent Type D63L150 120 current invention I 0
Corrugated Foil
Flat PMM +
P1701 159611 Turbulent Type D63L150 200 current invention I 0
Corrugated Foil
Table 9
Reference Figure 3.9
Sample Sample Dimensions Corrugation
Coating I
Structure description PGM
code No D*L (mm) (cpsi) (g/ft3)
P1700 159011_uc
Flat PMM + Straight
D63L150 300 no
Channel Corrugated Foil
Flat PMM + Straight current
P1700 159011_c D63L150 300 invention I
Ch~nnel Corrugated Foil
0
P1701 159711_uc Flat PMM +Turbulent Type Corrugated Foil D63L150 350 no
Flat PMM + Turbulent Type current
P1701 159711_c Corrugated Foil D63L150 350 invention I
0
Table 10
Reference Figure 3.10
Sample Dimensions Corrugation Coating I
code Sample No Structure description D*L (mm) PGM (cpsi) (g/ft3)
P1700 158811_uc Flat PMM+ Straight D63L150 100 no Channel Corrugated Foil
Flat PMM + Straight current
P1700 158811_c Channel Corrugated Foil D63L 150 100 invention I
0
P1701 159511_uc Flat PMM +Turbulent Type D63L150 120 no
Corrugated Foil
Flat PMM + Turbulent Type current
P1701 159511_c Corrugated Foil D63L150 120 invention I 0
5
Table 11
Reference Figure 3.11
Sample Sample Structure Dimensions Corrugation Coating I
code No description D*L (mm) (cpsi) PGM Comments (g/ft3)
Layered
Flat PfylM +Angle Current doughnut
167 411 Corrugated Screen D65L120 263 invention/ structure I
1 Rectangular
mesh
21
Flat inorganic
Layered
fibrous woven
Current doughnut
1674/2
matrix+ Angle
D65L120 263 invention/ structure I
1 Corrugated Screen Rectangular
mesh
Layered
Flat PMM + Angle
Current doughnut
1675 D65L2x60 263 invention/ structure I
Corrugated Screen . 1 Rectangular
mesh
Flat PMM + Angle
Current Rectangular
VF1 1676 D90L120 263 invention/
Corrug~ted Screen 1 mesh
Prior art substrate
Current
Rectangular
VL1 1687 D90L120 292 invention/
structure 1 mesh
Table 12
Reference Figure 3.12
Sample Sample Structure Dimensions Corrugation
Coating I
PGM Comments
.code No description D*L (mm) (cpsi) (g/ft3)
Flat PMM + Layered
Angle
Current doughnut
1669 D84L2x90 263 invention/ structure I
Corrugated 1 Rectangular
Screen mesh
Prior art Current Rectangular
VL1 1682 substrate D115L2x90 292 invention/
structure 1 mesh
" Flat PMM + Current
VF1 1683 Angle D115L2x90 263 invention/ Rectangular
Corrugated 1 mesh
Screen
Table 13
Reference Figure 3.13
Sample Sample Dimensions Corrugation
C'oating I
Structure description PGM Comments
code No D*L (mm) (cpsi) (g/ft3)
· VF1 1659 Flat PMM + Angle D80L74.5 Current Rectangular 263 invention/
Corrugated Screen 1 mesh
Flat PMM + Angle Current Rectangular
VF1 1660 D80L74.5 303 invention/
Corrugated Screen 1 mesh
Layered
Flat PMM + Angle Current doughnut
1673 Corrugated Screen D54L74.5 263 invention/ structure I
1 Rectangular
mesh
22
Table 14
Re f e rence F'l gure 4
Sample Sample Structure Dimensions Volume Corrug Coating/
ation PGM(g/c Mesh
Code No Description D*L(mm) (L) (cpsi) ft) shape
Prior art substrate 330 Prior
VX10 structure D63L152 art/1 0 Square
1404+1406
Prior art substrate
1.817
Prior
VXtO structure D75L304 330 art/10 Square
140111
Flat PMM + Angle
330 0
VF Corrugated Screen D63L152 0.468 Square
1448
Flat PMM + Angle 330 0 VF Corrugated Screen D63L152 0.468 Square
1461
Flat PMM + Angle
400 0
VF Corrugated Screen D63L120 0.374 Square
Table 15
Reference Figure 23.1
Sample Sample Dimensions Corrugation Coating
Structure description /PGM Mesh shape
code No D*L (mm) (cpsi) (g/ft3)
VX10 139412 Prior art substrate D63L152 330
prior art I
structure 10 Square
VL10 155816
Prior art substrate D63L152 330 prior art I Rectangular
structure 10
Flat PMM + Angle
current
VFO 158411 D63L150 330 invention Rectangular
Corrugated Screen 10
VX10 139512 Prior art substrate D75L304 330 prior art I
structure 10 Square
5
Table 16
Reference Figure 23.2
Sample Sample Structure Dimensions Corrugation Coating Mesh
/PGM
code No description D*L (mm) (cpsi) (glft3) shape
Flat PMM + Straight current
P1700 1589/1 Channel Corrugated D63L150 200 invention
Foil 10
Flat PMM + Straight current
1586/1 Channel Corrugated D63L150 300 invention Rectangular
Screen 10
Flat PMM + Straight current
P1700 159111 Channel Corrugated D63L150 400 invention
Foil 10
Flat PMM + current
P1701 159711 Turbulent Type D63L150 350 invention
Corrugated Foil 10
23
5 Table 17. Structural information from Prior Art nominal (Ref. 1) and front DOC (1675) and Prior Art VL-substrate
(1687) and Current invention Layered doughnut structures with Flat PMM + Layered doughnut Corrugated
Screen (167411) and Flat inorganic fibrous woven matrix+ Angle Corrugated Screen (167412)
Sample Sample Structure Dimensions Catalyzed Corrugation
Coating I
code No description D*L (mm) Volume PGM Position Comments
(dm3)
(Cpsi) (g/ft3)
DOC Ref.1 Prior art nominal
D80L120 0.603 350 Prior art 16 cc Turbulent
DOC structure with foils
DOC 1675
Prior art DOC I
D90L50.8 0.323 350
Prior art I cc Turbulent
Front 39 with foils
VL1 1687 Prior art substrate D90L 120 0.763 263 Prior art I 1 cc Rectangular
structure I Rear mesh
Layered
Flat PMM + Angle Current doughnt.Jt
VF1 167 4/1 Corrugated D65L2x60 0.103 263 invention I cc structure I
Screen I Rear 1 Rectangular
mesh
Flat inorganic Layered
fibrous woven Current doughnut
VF1 1674/2 matrix + Angle D65L2x60 0.103 263 invention I cc structure I
Corrugated 1 Fibrous
Screen I Rear matrix
1 o Figure 17 shows the structural information of the prior art substrates and structures of the current invention. It
is observed that for the substrates made of layered doughnut type of structures, the catalyst volume is only
(0.323 + 0.1 03) = 0.426 dm3 compared to that for the angle corrugated prior art structure (0.323 + 0.763) =
1.086 dm3, which is only 39.2 %.
15
Ta b l e 18 : Em 1. ss1. on te s t resu It s fo r th e samp1es presen te d .m Ta b l e 17
Ref. 1/ 1675 + 1675 + 1675 +
Sample DOC Ref.1/ DOC 1687 1687 1674/1 1675+ 1674/2
BSIII BSIV BSIV
without BSIII with BS Ill with . with with
Test EGR/· EGR/ EGR/ EGR/ EGR/ BS IV with EGR /I DC·
condition IDC-Hot IDC-Hot IDC·Hot IDC-Cold IDC-Cold Cold
co
(g/km) 0.104 0.18 0.048 0.097 0.096 0.105
THC
(g/km) 0.031 0.064 0.013 0.023 0.038 0.04
NOx
(g/km) 0.530 0.276 0.362 0.598 0.4 0.39
PM 0.018 0.079 0.021 0.026 0.023 0.023
24
(g/km) I
The mass emission tests were carried out on an Indian three wheeler test vehicle with BSIII and BSIV
driving cycles with or without EGR system. The mass emission of the said vehicle were measured in hot
condition on BSIII driving cycle and in cold condition on BSIV driving cycle. From Figure 18 it can be seen
5 that the current invention with Layered doughnut type of PMM or with inorganic Fibrous woven matrix gives
competitive mass emissio~s, especially in the case of particulate matter, with only 39.2% catalyzed volume
as compared to the prior art structure, when tests are done with the same preceding DOC.
Various embodiments are possible of the invention other than those disclosed above and are easily
comprehended by a person skilled in the art. The invention encompasses all such embodiments within its scope.
1 o While the present invention has been described with respect to certain preferred embodiments, it will be
apparent to those skilled in the art that various changes and modifications may be made without departing from
the scope of the invention as defined in the following claims.

We Claim:
1. A device for catalytic treatment of exhaust gases comprising of a substrate formed by connecting a
plurality of individual members wherein said individual member comprises of a plurality of cells.
2. The device as claimed in claim 1, wherein said individual member of said substrate forms a honeycomb
body.
3. The device as claimed in claim 1, wherein said plurality of cells are arranged in parallel or in series or in
parallel series with respect to each another.
4. The device as claimed in claim 1-3, wherein said cell is composed of metallic screen and PMM as its
walls.
5. The device as claimed in claim 1, wherein said cells have a cell density in the range from 20 to 1300
cells per square inch (cpsi), preferably from 50-600 cpsi
6. The device as claimed in claim 1 , wherein said members of said substrate is combined in unique ways
to form different ~eometries such as circular, oval, square, rectangular, doughnut shaped, banana
shaped, layered doughnut etc., each with or without a bypass and for different sizes.
7. The device as claimed in claim 1, wherein said members of said substrate can either be solid fitted or
can be partially open in radial and I or axial direction to give a variety of ftow patterns.
8. The device as claimed in claim 1, wherein said substrate is a three dimensional (3D) structure
combination of
a. Porous Metallic Medium (PMM) and
b. metallic screen.with different shapes of openings and different mesh numbers, and
c. optionally corrugated or micro corrugated notched metallic foil, and
d. optionally inorganic fibrous woven matrix material.
9. The device as claimed in claim 8, wherein said PMM is fteece.
10. The device as claimed in claim 8, wherein said shapes of openings is square or rectangular, preferably
rectangular.
11. The device as claimed in claim 8, wherein said corrugation is either straight or angular or turbulent.
12. The device as claimed in claim 8, wherein said angular corrugation has a corrugation angle in the
range of 10 to 60 degrees, preferably in the range of 32-40 degrees.
26
5
10
15
20
25
30
13. The device as claimed in claim 8, wherein said inorganic fibrous woven matrix material has an overall
thickness ranging from 0.5 to 100 millimeter in a single layer, preferably 0.5 -10 millimeter.
14. The device as claimed in claim 8, wherein said inorganic fibrous woven matrix material has a porosity
in the range of 70 to 95 %.
15. The device as claimed in claim 8, wherein said PMM has a porosity in the range of 70 - 95% and used
in varying thickness of 0.1 mm to 1 mm.
16. The device as claimed in claim 8, wherein said mesh numbers of the metallic screen is in the range of
120- 20 meshes per inch, preferably between 90- 30 meshes per inch.
17. The device as claimed iri claim 8, wherein said metallic screen has a wire diameter in the range of 0.08
- 0.3mm, preferably between 0.1 - 0.2 mm.
18. The device as claimed in claim 8, wherein said metallic foil has a thickness in the range of 20 - 11 0
micrometers, preferably between 40- 80 micrometers.
19. The device as claimed in claim 8, wherein said wherein said micro-corrugation height is in the range of
0.01 - 0.5 mm, preferably between 0.02-0.2 mm.
20. The device as claimed in claim 8, wherein said substrate exhibits high thermal and mechanical
durability at all engine loads.
21. The device as claimed ih claim 8, wherein said inorganic fibrous woven matrix material has a fiber
thickness in the range of 5 to 22 micrometers.
22. The device as claimed in claim 1-21, wherein said substrate further comprises of a coating of a
washcoat, wherein said washcoat comprises of a combination of catalytically inactive material and
catalytically active material.
23. The device as claimed in claim 22, wherein said washcoat is applied before or after the substrate is
formed.
24. The device as claimed in claim 22, wherein said catalytically inactive material includes a combination of
a variety of oxides, nitrates, and hydroxides of aluminum, silicon, titanium, zirconium, hafnium, calcium,
barium, strontium and rare earth metal oxides.
25. The device as claimed in claim 22, wherein said washcoat comprises of fine particles having a median
particle size distribution ranging between 0.5- 3.5 microns.
26. The device as claimed in claim 22, wherein said catalytically inactive material has a specific surface
area ranging between 100 to 260 sqm per g.
27
5
10
15
27. The device as claimed in claim 22, wherein said washcoat allows substantial in-situ generation of
nitrogen dioxide in the range of 20% to 50% by volume, which continuously allows efficient oxk.laliun
of soot accumulated inside the body of the honeycomb structure during the operation of the engine.
28. The device as claimed in claim 22, wherein said washcoat on said substrate provides same or lower
backpressure than that before coating.
29. The device as claimed in claim 22, wherein said washcoat coating provides catalytic performance at
low volume.
30. The device as claimed in claim 22, wherein said catalytically active material includes a combination of a
variety of salts of platinum, palladium, rhodium, ruthenium, osmium and iridium, preferably platinum,
palladium and rhodium.
31. The device as claimed in claim 30, wherein said catalytically active material is contained in said
honeycomb body in the range of 0.5 to 30 g/cubic feet, preferably from 1 -10 g/cubic feet.
32. The device as claimed in claim 22, wherein said washcoat coating is in the range of 0.5 to 10
micrometers thickness, preferably from 1 - 5 micrometers.