U.S. patent application number 13/978846 was filed with the patent office on 2013-10-24 for internal combustion engine exhaust line.
This patent application is currently assigned to PEUGEOT CITROEN AUTOMOBILES SA. The applicant listed for this patent is Gabriel Crehan. Invention is credited to Gabriel Crehan.
Application Number | 20130276432 13/978846 |
Document ID | / |
Family ID | 44146939 |
Filed Date | 2013-10-24 |
United States Patent
Application |
20130276432 |
Kind Code |
A1 |
Crehan; Gabriel |
October 24, 2013 |
INTERNAL COMBUSTION ENGINE EXHAUST LINE
Abstract
The invention relates to an exhaust line of an internal
combustion engine comprising: a pipe receiving exhaust gases, and a
particulate filter impregnated with a first catalytic coating
forming a reduction catalyst for nitrogen oxides (NO.sub.x), and
with a second catalytic coating forming a first oxidation catalyst
for carbon monoxide (CO) and hydrocarbons (HC). The line comprises
an additional filter housed in the pipe downstream of the
particulate filter and impregnated with a catalytic coating forming
a second reduction catalyst for nitrogen oxides (NO.sub.x). And,
the additional filter has an internal structure such that the
additional filter creates a pressure drop which is less than the
pressure drop created by the same volume of particulate filter
impregnated with the same quantity of the same catalytic
coating.
Inventors: |
Crehan; Gabriel;
(Vaucresson, FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Crehan; Gabriel |
Vaucresson |
|
FR |
|
|
Assignee: |
PEUGEOT CITROEN AUTOMOBILES
SA
Velizy Villacoublay
FR
|
Family ID: |
44146939 |
Appl. No.: |
13/978846 |
Filed: |
December 6, 2011 |
PCT Filed: |
December 6, 2011 |
PCT NO: |
PCT/FR2011/052878 |
371 Date: |
July 9, 2013 |
Current U.S.
Class: |
60/282 |
Current CPC
Class: |
F01N 3/08 20130101; F01N
13/02 20130101; F01N 2510/06 20130101; Y02A 50/20 20180101; Y02A
50/2325 20180101; F01N 3/035 20130101; F01N 3/2066 20130101; F01N
3/103 20130101 |
Class at
Publication: |
60/282 |
International
Class: |
F01N 3/08 20060101
F01N003/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 11, 2011 |
FR |
1150211 |
Claims
1.-10. (canceled)
11. An exhaust line for an internal combustion engine, said exhaust
line comprising: a pipe structured and operable for receiving
exhaust gases; a particulate filter, housed inside the pipe and
impregnated with: a first catalytic coating forming a first
reduction catalyst of nitrogen oxides (NOx), and a second catalytic
coating forming an oxidation catalyst for carbon monoxides (CO) and
hydrocarbons (HC); and an additional filter, housed in the pipe
upstream of the particulate filter, and impregnated with a
catalytic coating forming a second reduction catalyst for nitrogen
oxides (NOx), the additional filter comprising an internal
structure such that the additional filter creates a pressure drop
lower than the pressure drop created by the same volume of the
particulate filter impregnated with the same amount of the same
catalytic coating.
12. The exhaust line according to claim 11, wherein: the
particulate filter includes: intake ducts only leading to an inlet
face for the exhaust gases, exhaust ducts only leading to an outlet
face for the exhaust gases, and porous walls for fluidly connecting
the intake ducts and the exhaust ducts, and the additional filter
further comprises ducts leading to an inlet face and to an outlet
face, wherein the diameter of the ducts is greater than the pore
diameter of the porous walls of the particulate filter.
13. The exhaust line according to claim 11, wherein the specific
heat capacity of the material of which the additional filter is
made is lower than the specific heat capacity of the material of
which the particulate filter is made.
14. The exhaust line according to claim 13 further comprises a
reducing agent which decomposes when heated to produce a reagent
which intervenes in the reduction of nitrogen oxides by the first
catalytic coating, and an injector for injecting the reducing agent
into the pipe upstream of the additional filter.
15. The exhaust line according to claim 11, wherein the catalytic
coating with which the additional filter is impregnated comprises
zeolites so as to accelerate the decomposition of the reducing
agent.
16. The exhaust line according to claim 11, wherein at least one
of: the additional filter is made of cordierite, and the
particulate filter is made of silicon carbide.
17. The exhaust line according to claim 12, wherein the intake
ducts of the particulate filter are impregnated with only the first
catalytic coating, and the exhaust ducts are impregnated with only
the second catalytic coating.
18. A vehicle drive assembly, said assembly comprising: an internal
combustion engine; and an exhaust line, the exhaust line
comprising: a pipe structured and operable for receiving exhaust
gases; a particulate filter, housed inside the pipe and impregnated
with: a first catalytic coating forming a first reduction catalyst
of nitrogen oxides (NOx), and a second catalytic coating forming an
oxidation catalyst for carbon monoxides (CO) and hydrocarbons (HC);
and an additional filter, housed in the pipe upstream of the
particulate filter, and impregnated with a catalytic coating
forming a second reduction catalyst for nitrogen oxides (NOx), the
additional filter comprising an internal structure such that the
additional filter creates a pressure drop lower than the pressure
drop created by the same volume of the particulate filter
impregnated with the same amount of the same catalytic coating.
19. The assembly according to claim 18, wherein the engine is a
diesel type engine.
20. A vehicle comprising: a vehicle drive assembly, said assembly
comprising: an internal combustion engine; and an exhaust line, the
exhaust line comprising: a pipe structured and operable for
receiving exhaust gases; a particulate filter, housed inside the
pipe and impregnated with: a first catalytic coating forming a
first reduction catalyst of nitrogen oxides (NOx), and a second
catalytic coating forming an oxidation catalyst for carbon
monoxides (CO) and hydrocarbons (HC); and an additional filter,
housed in the pipe upstream of the particulate filter, and
impregnated with a catalytic coating forming a second reduction
catalyst for nitrogen oxides (NOx), the additional filter
comprising an internal structure such that the additional filter
creates a pressure drop lower than the pressure drop created by the
same volume of the particulate filter impregnated with the same
amount of the same catalytic coating.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention is the US national stage under 35
U.S.C. .sctn.371 of International Application No.
PCT/FR2011/052878, which was filed on Dec. 6, 2011 and which claims
the priority of application FR 1150211 filed on Jan. 11, 2011 the
content of which (text, drawings and claims) is incorporated here
by reference in its entirety.
FIELD
[0002] The invention relates to an exhaust line for an internal
combustion engine. The invention also relates to a drive assembly
comprising the exhaust line. Finally, the invention relates to a
vehicle equipped with the drive assembly.
BACKGROUND
[0003] The exhaust gases emitted from an internal combustion engine
contain pollutants whose release into the atmosphere it is
desirable to reduce. "Pollutants" designates, more particularly,
nitrogen oxides NOx (N20, NO and NO2), carbon monoxide (CO),
unburned hydrocarbons (HC) and soot particles. In order to limit
emissions of pollutants, it is known to carry out post-processing
of exhaust gases flowing through an internal combustion engine
exhaust line. Typically, the exhaust line of an internal combustion
engine comprises: [0004] a pipe receiving the exhaust gases from
the engine, [0005] a particulate filter for retaining and burning
the soot particles contained in the gases, [0006] an oxidation
catalyst to convert carbon monoxides (CO) and hydrocarbons (HC)
into carbon dioxides (CO2) and water (H2O), and [0007] a reduction
catalyst to convert nitrogen oxides (NOx) into nitrogen (N2) and
water (H2O).
[0008] In order to minimize the overall size of the exhaust line,
the oxidation catalyst and the reduction catalyst can be included
inside the particulate filter to form a filter particle called
"bi-catalyzed".
[0009] A bi-catalyzed particulate filter comprises generally a
honeycomb structure. The filter comprises an inlet face for the
entry of exhaust gases inside the filter and an outlet face for the
evacuation of exhaust gases from the filter. The filter comprises,
between the inlet and outlet faces, a set of channels or ducts
adjacent to axes parallel to one another, separated by porous
filtering walls. The ducts are closed off at one or the other of
their ends to delimit intake ducts leading only to the inlet face
and exhaust ducts leading only to the outlet face. The ducts are
alternately closed off in an order such that the exhaust gases,
while passing through the filter, are forced to pass through the
side walls of the intake ducts to reach the exhaust ducts. In this
way, the soot particles are deposited and accumulate on the porous
walls of the filter. These inner walls of the particulate filter
are impregnated with catalytic coatings to form the reduction
catalyst and the oxidation catalyst.
[0010] Typically, the particulate filter is made of silicon
carbide.
[0011] A first drawback of this type of bi-catalyzed particulate
filter is that, in order to ensure the regulatory decontamination
of exhaust gas, it is necessary that the amount of impregnated
catalytic coating on the walls be greater than a minimum
threshold.
[0012] If the amount of impregnated catalytic coating on the walls
is excessive, the pores of the porous walls of the filter get
clogged up. In such case, during operation of the engine, the
exhaust gases pass through the filter with more difficulty.
Consequently, the pressure of the exhaust gases in the pipe
increases at the inlet of the particulate filter. Indirectly, an
obstruction of the pores results in an increase in the fuel
consumption of the engine.
[0013] A known solution is to increase the volume of the
particulate filter so that more catalytic coating can be deposited
without clogging the pores of the filter. However, this solution is
to be avoided as it increases the overall size of the exhaust
line.
[0014] A second drawback is that the reduction of nitrogen oxides
(NO.sub.x) requires that the temperature of the exhaust gases be
greater than a threshold temperature in order to take place. The
lower the temperature of the exhaust gases, the lower the amount of
reduced nitrogen oxides. The filter being made of silicon carbide,
it dissipates the heat of the exhaust gas passing through this
filter and therefore decreases the amount of the reduced nitrogen
oxides. Under these conditions, it is known to increase the amount
of catalyst in the particulate filter in order to maintain a
satisfactory amount of reduced nitrogen oxides at low temperature.
However, that amount of catalyst (typically precious materials) is
often significant. Such addition of catalyst is costly to the
filter manufacturer.
[0015] A third drawback is that, in order to allow the reduction of
nitrogen oxides (NO.sub.x), a reducing agent, typically urea, is
injected into the pipe upstream of the filter. In the exhaust lines
known to the applicant, it is necessary to inject the reducing
agent far upstream of the particulate filter to allow time for the
urea to break down into ammonia (NH.sub.3) as a result of the heat
from the exhaust gases. This is problematic for small vehicles in
which the pipe is short.
SUMMARY
[0016] The invention aims to overcome one or more of these
drawbacks.
[0017] The invention relates to an exhaust line for an internal
combustion engine, this exhaust line comprising: [0018] a pipe
receiving the exhaust gases, and [0019] a particulate filter housed
inside the pipe impregnated with: [0020] a first catalytic coating
forming a first reduction catalyst of nitrogen oxides (NO.sub.x),
and [0021] a second catalytic coating forming an oxidation catalyst
for carbon monoxides (CO) and hydrocarbons (HC), [0022] an
additional filter, housed in the pipe upstream of the particulate
filter, and impregnated with a catalytic coating forming a second
reduction catalyst for nitrogen oxides (NO.sub.x), and [0023] the
additional filter comprises an internal structure such that the
additional filter creates a pressure drop lower than the pressure
drop created by the same volume of the particulate filter
impregnated with the same amount of the same catalytic coating.
[0024] In the exhaust line presented above, the additional filter
can be impregnated with an amount of first catalytic coating per
unit volume greater than the particulate filter. Thus, in order to
increase the amount of the catalytic coating in the exhaust line,
while not clogging the pores of the particulate filter, it is less
cumbersome to add the additional filter to the exhaust line than to
lengthen the particulate filter.
[0025] Moreover, the additional filter creates a pressure drop
lower than the pressure drop that would be created by the same
volume of the particulate filter impregnated with the same amount
of catalytic coating as the additional filter. Thus, the
consumption of the engine is not worsened compared to that with a
lengthened particulate filter.
[0026] The embodiments of this exhaust line can include one or more
of the following characteristics: [0027] an exhaust line, wherein:
[0028] the particulate filter comprises: [0029] intake ducts
leading only to an inlet face for the exhaust gases, [0030] exhaust
ducts leading only to an outlet face for the exhaust gases, and
[0031] porous walls for fluidly connecting the intake ducts and the
exhaust ducts, [0032] the additional filter comprises ducts leading
to an inlet face and to an outlet face, the diameter of these ducts
being greater than the pore diameter of the porous walls of the
particulate filter, [0033] the specific heat capacity of the
material of which the additional filter is made is lower than the
specific heat capacity of the material of which the particulate
filter is made, [0034] the line comprises a reducing agent which
decomposes when heated to produce a reagent which intervenes in the
reduction of nitrogen oxides by the first catalytic coating and an
injector for injecting the reducing agent into the pipe upstream of
the additional filter, [0035] the catalytic coating of which the
additional filter is impregnated comprises zeolites in order to
accelerate the decomposition of the reducing agent, [0036] the
additional filter is made of cordierite and/or the particulate
filter is made of silicon carbide, and [0037] an exhaust line,
wherein: [0038] the intake ducts of the particulate filter are only
impregnated with the first catalytic coating, and [0039] the
exhaust ducts are only impregnated with the second catalytic
coating.
[0040] The embodiments of this exhaust line include the following
additional benefits: [0041] when the diameter of the ducts of the
additional filter is greater than the pore diameter of the
particulate filter, it is possible to impregnate the additional
filter with an amount of catalytic coating per unit volume greater
than for the particulate filter while creating a lower pressure
drop, [0042] when the specific heat capacity of the additional
filter is lower than the specific heat capacity of the particulate
filter, the additional filter temperature rises faster than that of
the particulate filter which allows starting the reduction of
nitrogen oxides at a lower temperature when starting the engine,
[0043] when the catalytic coating of the additional filter
comprises zeolites, the decomposition of the reducing agent is
accelerated by the additional filter which indirectly allows
shortening the length of the pipe upstream of the additional
filter, and [0044] when the intake ducts are only impregnated with
the first catalytic coating, and the exhaust ducts are only
impregnated with the second catalytic coating, the amount of
ammonia, entrapped in the first coating and oxidized by the second
coating to form nitrogen oxides NOx, is limited.
[0045] The invention also relates to a drive assembly, the assembly
comprising: [0046] an internal combustion engine, and [0047] an
exhaust line as described above.
[0048] The invention finally relates to an engine vehicle equipped
with the drive assembly.
DRAWINGS
[0049] Other features and advantages of the invention will become
clearly apparent from the description which is given below, as an
indication in no way restrictive, with reference to FIG. 1. FIG. 1
is a partial schematic illustration of a vehicle equipped with a
drive assembly comprising an exhaust line, in accordance with
various embodiments of the invention.
DETAILED DESCRIPTION
[0050] In the remainder of this description, the features and
functions well known to those skilled in the art are not described
in detail.
[0051] FIG. 1 shows a vehicle 2 such as an automobile. For example,
vehicle 2 is a car. This vehicle 2 is equipped with a drive
assembly 4. The assembly 4 comprises an internal combustion engine
6 and an exhaust line 8.
[0052] The engine 6 is capable of rotating the drive wheels 10 of
the vehicle 2. In various embodiments, the engine 6 is a diesel
engine. During operation, the engine 6 is discharging exhaust gases
which, before being expelled to the outside of the vehicle 2, are
received by the exhaust line 8 capable of processing these
gases.
[0053] The exhaust line 8 comprises a pipe 12 receiving the exhaust
gases through an opening 13 in an exhaust manifold of engine 6. For
example, the pipe 12 is a cylindrical tube of circular section. In
various embodiments, the pipe 12 is made of steel.
[0054] The exhaust line 8 includes a particulate filter 14 (also
known as FAP) able to retain the soot particles contained in the
exhaust gases and burn these particles. In various embodiments, the
filter 14 is adapted to retain particles of a diameter greater
than, or equal to 23 nm. The filter 14 is housed inside the pipe
12.
[0055] In various embodiments, the filter 14 is advantageously made
of silicon carbide. In various embodiments, the filter 14 includes
a honeycomb structure. In this example, the internal structure of
the filter 14 is known per se. It has already been presented in the
introduction, so it is not described in detail. Hereafter,
reference 16 and 18 designate, respectively, the inlet face and the
outlet face of the filter 14.
[0056] The filter 14 includes a plurality of intake and exhaust
ducts. In order to simplify FIG. 1, only one intake duct 20 leading
to the inlet face 16, and one exhaust duct 22 leading to the outlet
face 18, are shown. In various embodiments, the ducts 20 and 22 are
bonded to each other by means of cement. Typically, this cement can
comprise one or more of the following chemical species: cordierite,
SiC, B.sub.4C, Si.sub.3N.sub.4, BN, AlN, Zr0.sub.2, mullite, AL
titanate, ZrB.sub.2, and/or Sialon (an alloy of silicon, aluminum,
oxygen and nitride).
[0057] In various embodiments the length of the filter 14 is
between 5 cm and 75 cm. For example, the length can be between 18
cm and 25 cm.
[0058] The filter 14 is a bi-catalyzed filter. For this purpose,
the porous walls of the ducts are impregnated with two catalytic
coatings.
[0059] In various embodiments, the porous walls of the intake ducts
20 are only impregnated with a catalytic coating R.sub.cat1. The
coating R.sub.cat1 forms a selective reduction catalyst (also known
as SCR). This selective reduction catalyst is capable of converting
the nitrogen oxides (NOx) contained in exhaust gases passing
through the filter 14 into nitrogen (N2) and water (H20). The
R.sub.cat1 catalytic coating is known per se. In various
embodiments, the R.sub.cat1 coating contains one or more of the
following chemical species: Al.sub.20.sub.3, Ti0.sub.2, Zr0.sub.2,
Ce0.sub.2, Y.sub.20.sub.3, Pr0.sub.2, Si0.sub.2.
[0060] In various embodiments, the porous walls of the exhaust
ducts 22 are only impregnated with a catalytic coating R.sub.cat2.
The R.sub.cat2 coating forms a diesel oxidation catalyst (also
called DOC). The diesel oxidation catalyst is capable of converting
the carbon monoxides (CO) and hydrocarbons (HC) contained in the
exhaust gases passing through the filter 14 into carbon dioxide
(CO.sub.2) and water (H.sub.2O). The R.sub.cat2 catalytic coating
is known per se. For example, the R.sub.cat2 coating contains one
or more of the following chemical species: Al.sub.2O.sub.3,
TiO.sub.2, ZrO.sub.2, CeO.sub.2, Y.sub.2O.sub.3.
[0061] The R.sub.cat1 and R.sub.cat2 coatings further contain a
catalyst. For example, the catalyst is a material or alloy of
materials belonging to the platinum group (also called "Platinum
Group Metals (PGM)). "Platinum Group Metals" designates here the
rhodium (Rh), the ruthenium (Ru), the iridium (Ir), the rhenium
(Re), the osmium (Os), the platinum (Pt) and the palladium (Pd). In
various embodiments, the catalyst is an alloy of platinum (Pt) and
palladium (Pd).
[0062] In various embodiments, the mass of materials belonging to
the platinum group is greater in the catalytic coating R.sub.cat2
than in the catalytic-coating R.sub.cat1.
[0063] Advantageously, in various embodiments, the total amount of
catalytic coatings impregnated in the filter 14 is greater or equal
to 50 g per liter of filter and, in various implementations, the
total amount of impregnated catalytic coatings is greater than 100
g per liter of filter. Generally, the amount of catalytic coating
in the filter 14 is lower than 200 g per liter of filter. In
various embodiments, the R.sub.cat1 coating and the R.sub.cat2
coating each represents between 40% and 60% of the total volume of
impregnated catalytic coating.
[0064] The exhaust line 8 also includes a reservoir 26. The
reservoir 26 contains a reducing agent for reducing the nitrogen
oxides (NO.sub.x) contained in exhaust gases into nitrogen
(N.sub.2) and water (H.sub.2O). Typically, the reducing agent is
urea. Under the effect of heat, the urea is decomposed into ammonia
(NH.sub.3) which reacts with the NO in the reduction catalysts
coatings to reduce the NO.sub.x. The reducing agent is injected
into the pipe 12 upstream of the particulate filter 14 through an
injector 28. In the example, the injector 28 injects urea
downstream of a turbo-compressor (not shown). Also in various
embodiments, the injector 28 comprises a temperature sensor for the
exhaust gases upstream of the particulate filter 14.
[0065] In this description, the terms "downstream" and "upstream"
are defined relative to the direction of flow of exhaust gases in
the pipe 12. The direction of flow of the exhaust gases in the pipe
12 is represented by arrows in FIG. 1.
[0066] The exhaust line 8 also includes an additional filter 30.
The filter 30 is adapted to carry out the reduction of nitrogen
oxides (NO.sub.x) contained in the exhaust gases into nitrogen
(N.sub.2) and water (H.sub.2O).
[0067] The filter 30 comprises ducts 33 passing through the filter
30 from end to end. The ducts 33 lead to an inlet face 32 and an
outlet face 34. To simplify FIG. 1, only two ducts 33 are shown.
The ducts 33 are separated by inner walls 35. In various
embodiments, these walls 35 are less porous than the walls of the
filter 14.
[0068] The inner walls 35 of the filter 30 separating the ducts 33
are impregnated with a catalytic coating R.sub.cat3 forming a
reduction catalyst. In various embodiments, the R.sub.cat1 and
R.sub.cat3 coatings have the same chemical composition with the
exception that the R.sub.cat3 coating contains zeolites so that
when the exhaust gases pass through the ducts 33, the R.sub.cat3
coating accelerates the decomposition of urea into ammonia.
[0069] Under these conditions, a longer length of the pipe 12,
between the injector 28 and the filter 14, so that the exhaust
gases remain long enough in contact with the urea to bring it to
the decomposition temperature, is no longer necessary. The length
of the pipe 12 upstream of the filter 14 can then be shortened.
[0070] Furthermore, the internal structure of the filter 30 is such
that, at equal volume with the filter 14, the filter 30 is adapted
to be impregnated with an amount of R.sub.cat3 coating per unit of
volume greater than the filter 14, while creating a pressure drop
lower than the pressure drop created by the same volume of the
particulate filter 14. To this end, in various embodiments, the
diameter of the ducts 33 is greater than the pore diameter of the
inner walls of the particulate filter 14.
[0071] Indeed, the ducts 33 passing through the filter 30 from end
to end, and the wall 35 having low porosity, the pressure drop
generated by the filter 30 depends on the length of the filter 30,
the amount of coating impregnated in the walls 35 and the diameter
of the ducts 33. In contrast, the ducts 20 and 22 being closed off
at one face of the filter 14, the pressure drop generated by the
filter 14 depends on the length of the filter 14, the amount of
impregnated coating, and the size of the pores of the porous
walls.
[0072] The additional filter 30 is housed in the pipe 12 between
the injector 28 and the particulate filter 14. In various
embodiments, the distance between the filters 14 and 30 is less
than 20 millimeters, for example less than 10 mm.
[0073] In the remainder of this description, the term "specific
heat capacity of a material" means the energy that must be brought
to a mass of 1 kg of that material to increase its temperature by
one Kelvin. The heat capacity is expressed in Joule.
Kelvin.sup.-1.Kg.sup.-1. The specific heat capacity of a material
defines the ability of this material to absorb and release
heat.
[0074] Advantageously, the heat capacity of the material of which
the additional filter 30 is made is lower than the heat capacity of
the material of which the particulate filter 14 is made. Under
these conditions, during operation of the engine 6, the temperature
inside the filter 30 reaches the temperature of "light-off" faster
than the filter 14. Temperature of "light-off" means the starting
temperature at which 50% of nitrogen oxides (NO.sub.x) contained in
the exhaust gases are reduced by the reduction catalyst coating. In
these conditions, reduction of nitrogen oxides (NO.sub.x) is
carried out faster in the filter 30 than in the filter 14, which
allows cleaning the exhaust gases sooner when starting the engine
6.
[0075] Furthermore, in various embodiments, in order to allow the
additional filter 30 to warm up quickly, the length of the filter
30 is advantageously between 2 cm and 10 cm, for example, between 5
cm and 10 cm.
[0076] In various embodiments, the filter 30 is a cordierite
monolith.
[0077] The exhaust line 8 also comprises sensors 36 and 38 for the
amount of NO.sub.x contained in the exhaust gases, respectively,
upstream of the filter 30 and downstream of the filter 14.
[0078] The exhaust line 8 finally includes a calculating unit 40
that is structured and operable to: [0079] obtain measurements from
the sensors 36 and 38, and [0080] control the quantity of urea
injected by the injector 28 in the pipe 12 according to the
measurements obtained.
[0081] For example, in various embodiments, the unit 40 is made
from a programmable electronic calculator capable of executing
instructions stored on a data recording medium 42. For this
purpose, the unit 40 is connected to the data recording medium 42
containing instructions for the execution of a control method of
the sensors 36, 38 and the injector 28.
[0082] Many other embodiments are possible.
[0083] Other materials can be used to produce the filters 14 and
30. For example, the filters 14 and 30 can include one or more of
the following: cordierite, SiC, B.sub.4C, Si.sub.3N.sub.4, BN, AlN,
Al.sub.2O.sub.3, ZrO.sub.2, mullite, Al titanate, ZrB.sub.2, and
Sialon.
[0084] The R.sub.cat1 coating can also be acid.
[0085] In the R.sub.cat1 and R.sub.cat3 coatings, the catalyst does
not necessarily include a material from the platinum group. Other
catalysts can be used in addition to, or replacement. For example,
the catalyst can be one of the following precious metals: gold
(Au), and/or silver (Ar). The catalyst can also include alkali
metals, alkaline earth metals, lanthanide metals, actinide metals,
transition metals, and/or perovskites. A transition metal can be
scandium (Se), titanium (Ti), vanadium (V), chromium (Cr),
manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) or
zinc (Zn).
[0086] In R.sub.cat2 coatings, the catalyst does not necessarily
include a material from the platinum group. In various embodiments,
other catalysts can be used in addition to, or replacement. For
example, the catalyst can be one of the following precious metals:
gold (Au), and/or silver (Ar). The catalyst can also comprise
transition metals, alkali metals, alkaline earth metals, lanthanide
metals, hydrocarbon traps such as zeolites or clay, actinide
metals, and/or perovskites.
[0087] In various embodiments, the injector can be placed upstream
of the turbocharger.
[0088] In various embodiments, reducing agents other than urea can
be used.
[0089] In various embodiments, the catalytic coatings R.sub.cat1
and R.sub.cat3 can be of the same chemical composition.
[0090] In various embodiments, the sensors 36, 38 can be omitted.
In such instances, the unit 40 can control the injector 28 from
pre-stored formulas or tables.
[0091] The engine is not necessarily a diesel type engine. The
engine can be a gasoline type engine. In such embodiments, the
particulate filter 14 can be impregnated in order to implement the
functions of a three-way catalyst.
* * * * *