Note: Descriptions are shown in the official language in which they were submitted.
1~6SZ47
This invention relates to the reduction of smoke and
other noxious components contained in gases and in particular
exhaust gases.
Gases from boilers and internal combustion engines often
contain finely divided particles of hydrocarbons and/or
carbon or other solid matter which emerge in the form of
smoke. The smoke from a diesel engine is composed of solid/
liquid particles (i.e., solid particles having a liquid outer
covering ~ayer), solid chain aggregates in which spherical
particles of between 100-800~ diameter link up together,
liquid sulphates, l.iquid hydrocarbons and gaseous hydrocar-
bons. The solid/liquid particles generally comprise carbon
particles with adsorbed liquid hydrocarbons and the solid
chain aggregates are generally composed of high molecular
weight organic compounds and/or inorganis sulphates.
White smoke i5 produced when the engine first starts up
and results from the condensation of water vapour on to
particulates contained in the exhaust gas so that a fine mist
is formed. Black smokes produced by diesel engines are
formed when the engine has warmed up and contains a relatively
~165Z~7
high proportion of carbon particles. In blue smoXe there
is some carbon but also a relatively high proportion of
gaseous organic compounds such as aldehydes. About 90~
of these smoke forming particles have maximum dimensions
of less than one micron which is within the respirable
particle size and the maximum dimension of the remaining
10~ of these smoke forming particles are less than four
microns.
One object of the present invention is at least to
reduce the quantity of smoke contained in waste gases by
effecting the catalytic oxidation of smoke forming parti-
cles in the~e gases.
A second object of the present invention is to
reduce the quantity of noxious gases and particulates
present in exhaust gas of an internal combustion engine.
A further object of the present invention is to pro-
vide a modified diesel or petrol driven internal combus-
tion engine such that a considerable reduced quantity of
noxious gases and particulates is produced.
In this specification the term "pollutants" should
be taken to include hydrocarbons, carbon monoxide and
oxides of nitrogen formed by the internal combustion
engine as well smoke forming particles described above.
1165~47
-- 3 --
According to a first aspect of the present invention
internal combustion engine includes apparatus for reducing
pollutants contained in exhaust gases emitted from the
engine having at least on exhaust port, the apparatus com-
prising a casing defining a chamber containing a catalyst,
the catalyst including a substrate made from filamentary
metallic material in knitted, woven or crushed form, a Eirst
layer of a refractory metal oxide applied to the substrate
and a second layer of a catalytic material applied to the
first layer, the chamber having an inlet in communication
with the said exhaust port via which exhaust gas emitted
from the engine is lead into the chamber and passed through
the catalyst prior to passage through an exhaust system to
atmosphere.
lS Usually, the catalytic oxidation of carbon particulates
takes place at about 400C whereas the normal temperatures
of combustion of such particulates is 700-800C. For hydro-
carbon particles catalytic oxidation will take place at
temperatures about 200C. The effect of a catalyst on the
temperature at which catalytic oxidation of particulates
entrained in the exhaust gas stream of a diesel engine took
place were studied. ~ number of sample catalysts were
prepared. The catalysts comprised a substrate fabricated
116524~
from 310 stainless steel wire of diameter 0.010 inch, rolled
down to ribbon 0.004 inch thick, a layer of alumina and a
layer of one or more platinum group metal(s) at a loading of
2.46 mg/g of alumina. A portion of coated wire was cut from
a catalyst and heated gradually raising the temperature
together with particulate matter, collected from the exhaust
gas stream of a diesel engine, in the sample pan of a differ-
ential scanning colorimeter (a DSC) in an atmosphere of 1~
oxygen in argon. Samples of the atmosphere above the sample
pan were taken via a heated capillary tube to a mass spec-
trometer. Four mass numbers were traced: carbond monoxide
(44), doubly charged argon (20), oxygen (32) and water (18)
or nitrogen and carbon monoxide (28). The temperature at
which the differential plot of the DSC peaked was taken to be
the temperature at which combu~tion of the particulates took
place. This temperature can be referred to as the "light-
off" temperature. The results are given below:
Alumina Loading Light-off
(g/g of wire)Catalytic metal(s)temperature (C)
0.33 5.7% Rh 94.3% Pt 235
0.28 67& Pt 33~ Pd 207
0.30 Pd 265
0.28 Pt 220
1~65Z47
- 5 -
The light-off temperature of particulates from the exhaust
gas stream of a diesel engine, 207-265C, is considerably
lower than the temperature for combustion to take place
when no catalyst is present.
~ 5 Since the presence of a catalyst enables oxidation of
- the smoke forming particles in a gas to take place at a
lower temperature than the normal temperature at which com-
bustion takes place, when it is desired to effect the cata-
lytic oxidation of any smoke forming particles in the ex-
haust gas from an internal combustion engine little or no
heating is, consequently required. This is due to the fact
that when a diesel engine is operated at medium to full
power the temperature thereof i8 about 400C so that no
preheating of the exhaust gas issuing from the engine is
required before passing the said exhaust gas over a cata-
lyst.
The filamentary metallic substrate may be in the form of
wire and is disposed 80 as to provide maximum contact of the
catalytic metal with the said exhaust gases. Preferably the
wire is in a flattened form, usually obtained by rolling down
prior to the deposition of washcoat and catalytic metal. In
- the operation of a diesel or similar engine in which an
excess of air or oxygen is present in the combustion chamber
.
11~5247
-- 6 --
such contact ensures that a substantial proportion of the
pollutants as above described undergo catalytic oxidation.
A preferred disposition of the metallic wire substrate
within the said chamber is such that turbulence is induced
in the exiting gases.
According to a second aspect of the present invention
a process for the reduction of pollution by exhaust gas
from internal combustion engines comprises passing the said
exhaust gas from the cylinders of the said engine into a
chamber containing a catalyst on a support of design such
that turbulence is produced and the pollutants present in
the exhaust gas come into contact with the said catalyst
and at least part of the said noxious components and parti-
culates undergo catalytic oxidation. Preferably the said
engine i8 a diesel engine.
Features of an internal combustion engine according -to
the present invention include:
i) a chamber having an outerwall with a plural-
ity of entry ports adjacent to the exhaust
valves of the said enbing and an exit port
adjacent to the exhaust pipe; and
ii) a supported catalyst so positioned that the
1~L65247
exhaust gas flowing into the said chamber
from the exhaust ports has to pass through
the said catalyst which is so disposed such
that the exhaust gas flow is turhulent at
least while the said gas is in contact with
the said catalyst.
Preferably the catalyst used in the said internal com-
bustion engines comprise:
a) a divided substrate which is positioned in
the path of the gas flow so as to create
turbulence in the exhaust gas stream;
b) an adherent refractory metal oxide washcoat
layer disposed upon the surface of the sub-
strate; and
c) a catalytic metal selected from the group
consisting of Ru, Rh, Pd, Ir, Pt, Fe, Co,
Ni, V, Cr, Mo, W, Y, Ce, alloys thereof and
intermetallic compounds containing at least
20% by weight of one or more of the said
metals disposed upon the surface or through-
out the refractory metal oxide washcoat layer.
The reEractory metal oxide washcoat layer preferably
contains in the form of their oxides one or more members oE
'; '
~65247
the group consisting of Mg, Ca, Sr, Ba, Sc, Y, the lanthan-
ides, Ti, Zr, Hf, Th, Ta, V, Cr, Mn, Co, Ni, B, Al, Si and
Sn.
A preferred washcoat material as A1203 and alumina hy-
drates but stabilizing oxides such as BaO and oxides promoting
catalytic activity such as Tio2, ZrO2, HfO2, ThO2, Cr2O3and
NiO may also be present.
One preferred form of catalytic substrate comprises a
structure made up from woven or knitted wire and an even more
preferred form is woven or knitted wire which has been rolled
down before fabrication into woven or knitted form. Suitable
alloys which may be used in the manufacture of the wire are
corrosion resistant and particularly oxidation resistant base
metal alloys.
Examples of such base metal alloys are nickel and chrom-
ium alloys having an aggregate Ni plus Cr content greater than
20% by weight and alloys of iron including at least one of the
elements chromium (3-40) wt %, aluminum (1-10) wt %, cobalt
(trace-5) wt ~, nickel (trace-72) wt ~ and carbon (trace-0.5)
wt ~. Such substrates are described in German DOS 2450664.
Other example~ of base metal alloy~ capable o~ with-
standing the rigorous conditions required are iron-aluminum-
chromium alloys which may also contain yttrium. The latter
~165247
alloys may contain 0.5-12 wt % Al, 0.1-3.0 wt % Y, 0-20 wt
% Cr and balance Fe. These are described in United States
Patent No. 3298826. Another range of Fe-Cr-Al-Y alloys contain
- 0.5-4 wt ~ Al, 0.5-3.0 wt % Y, 20.0-95 wt % Cr and balance Fe
and these are described in United States Patent No. 3027252.
Alternatively the base metal alloys may have less
- corrosion resistance, e.g. mild steel, but with a protective
coating composition covering the surface of the substrate as
described in Canadian Patent No. 1,128,031.
Where wire is used as a substrate its thickness is
preferably between 0.001 and 0.02 inches thick and more
preferably between 0.001 and 0.012 inches thick.
The invention is urther illustrated by the following
specific embodiments described with reference to Figures 1 to
4 Of the drawings and by the following Examples, results from
which are shown as graphs by the Figures 5 to 14 of the drawings.
In the drawings,
Figure 1 shows a section through an apparatus suitable
for use in combination with a diesel engine according to the
invention,
Figure 2 shows a section through an alternative apparatus,
Figure 2a shows on a larger scale a section through a
further alternative apparatus,
Figure 3 shows in perspective an assembly of supporting
bars suitable for acting as a central support in the apparatus,
Figure 4 shows in perspective an alternative central
support for the apparatus,
Figures 5 to 9 show graphs of the composition of
pollutants in exhaust gas discharging from a diesel engine
~ 9 _
1 -~,
~' ,1
, ' ' , ' '
., .
'
6S;~47
operated on an LA4 cold start cycle versus miles notionally
travelled,
Figures 10 to 14 show similar graphs to those of
Figures 5 to 9 but obtained from a diesel engine operated on
S an LA4 hot start cycle.
In one embodiment of the present invention the catalyst
is contained in a reaction tube which is positioned substantially
centrally in the exhaust chamber. The embodiment will be
described with reference to Figure 1. The outer wall, 1, of
the exhaust chamber has openings 7, 8, 9 and 10 which are
adjacent to and continuous with the exhaust ports of the cylinders
and one exit, 12, adjacent to exhaust pipe, 11. The reaction
tube, 2, which is supported in the chamber by
.
:~ ww.s . - 9a -
, P~ r,~-
' .
'. '
~ . .. .. . .
1165247
-10-
struts 5 and 6 contains the supported catalyst 3. The
reaction tube is so positioned that the exhaust gas on
entering the exhaust chamber has to pass through the reaction
- tube and so come into close and continuous contact with the
catalyst before leaving the exhaust chamber and entering the
exhaust pipe. Tile exhaust gas flow through the exhaust
chamber is generally indicated by the labelled arrows Fl,
l F2, F3, F4, F5 and F6. Combusted gas flows in frt~m the
cylinder ports throllgh the openings 7, 8. 9 and 10 and flows
along the reaction tube, 2, and out into the exhaust pipe,
11. A retaining bar, 4, is placed across the exit of the
reaction tube to ensure that the catalyst remains in position.
~ he catalyst support is preferably oi knitted wire
mesh. This may be ~abricated into a single monolith or it
may be made up in annular sections.
'l~ne layer of washcoat and the catalytic layer may be
applied to e;~ch section separately or after the sections
have been linked together. Alternatively the support, in
sections or linked together, may have the wa~hcoat and
1 catalytic leyer applied after it has beén pla~ed in the
reaction tube.
A further embodiment will be described with reference
to Figure 2. T~le outer wall, 21, o the catalyst chamber has
, '' . . ' .
'
~:165Z47
openings 27, 28, 29 and 30, adjacent and continuous with the
exhaust ports of the cylinders and one exit, 32, adjacent to
the exhaust pipe, 31. The catalyst, 23, comprising a support,
a washcoat layer and a catalytic metal is sc disposcd so that
the exhaust gas on entering the catalyst chamber is compelled
to pass through the interstices of the sald sacalyst before
leaving the chamber and entering the exhaust pipe. The
exhaust gas flows through the catalyst chamber as indicated
by the labelled arrows, F41, F42, F43, F44 45
flows i~ from the exhaust ports as shown by F41, F42, F43 and
F44 and then through the catalyst and out into the exit tube
22 as silown by F4s.
In this embodiment the support for the catalyst is
preferabLy of knitted wire which may be made up into sections
or as one unit but if it is in sections, e.g., of do4ghnut
configuration, these are normaily lir.ked together before the
support is placed in the chamber. One end of the support is
closed off by joining, e.g., by -~7e1ding, a disc, 26, to it and
an ann~lar disc, 25, at the other end holds the su~port in
position. The supported catalyst is ~lisposed in the catalyst
chamber as shown in Figure 2 by attaching the ends covered
by the discs, 25 and 26, to the outer walls of the chamber.
.,j .
,. :
1~65Z47
-12-
To ensure that the support does not collapse inwards a
cylindrical and perforated exit tube, 22, positioned in the
catalyst chamber allows gas to pass through it and continue
to the exhaust pipe, 31. The tube, 22, may be constructed
of wire mesh or it may be a perforated metal tube having
holes or slots.
Figure 3 depicts ~m alternative embodiment in which
in place G~ a pérforated exit tube in the catalyst chamber a
series of S rigid bars, 100-500, running the length of the
chamber are used. These are mainta;ned in fixed spatial
relationship to one another, thus holding the supported
catalys~: rigidly in place within the chamber, by the use of
spacing p~ates, 600. The spacing plates in pairs connect
three of the five bars and are usually at right angles to
each other thus being disposed along a diameter oE the
central cylindrical exit tube. Two or ~ore pairs of
spacing pla~es may be used and they are usually positioned
at regùlar intervals in the lengtiL of the chamber. Alterna-
tively the spacing plates may be used instead of rods where
they would be continuous throughout th~ length of ~he chamber
as shown in Figure 4. Rods and spacing plates need to be
constructed of a material resistant to oxidation up to at
least 800C.
, .
:. ....
- 1~65Z47
.
- 13 -
A further embodiment will be described with reference
to Figure 2A in which, for convenience, only two exhaust
ports are shown. The outer wall 100 of the catalyst chamber
has openings, 101 and 102 adjacent to and continuous with
the exhaust ports of the cylinders and one exit, 103, adja-
cent to the exhaust pipe. The catalyst, 104, comprising a
support, a washcoat layer and a catalytic metal is so dis-
posed that the exhaust gas has to pass through the catalyst
before leaving the chamber. The cataly~t is disposed in the
chamber using spacing plates, 105, as described above. One
end of the spacing plates, 109, is fixed to the chamber
wall, 100, and a disc or metal plate, 108, is attached to
the other end of the spacing plates to ensure that no
exhaust gas can leave the chamber without passing through
the cataly~t. The exhaust gas flows into the chamber
through the openings, 101 and 102, and down through sleeves,
106 and 107, into the inner space 110 provided by the spac-
"
ing plates, 105. The exhaust gas then flows through thecatalyst outwards and then through the exit, 103. The ~low
of the exhaust gas i9 indicated by the labelled arrows
Fg -Flo9-
The support for the catalyst is preferably of knitted
wire which may be made up into four sections or three units.
: .
:
. .
. .
1~65Z47
..,
If the support is in sections, e.g., of doughnut configura-
tion, these are normally linked together before the support
is placed in the chamber.
le 1
' .
The (2000 cc capacity) multicylinder engine of a com-
mercially available diesel engine-powered automobile was
modified to demonstrate the results obtained in operation of
the pre~ent invention.
A catalyst chamber as outlined in the ~irst embodiment
(Figure 1) of the invention, as described above, was itted
to the engine. A knitted mesh catalyst support was made from
, wire having the following composition:
% wt -
Cr - 15
Al 4
Y 0.3
Fe ~alance
Deposited on this support W&S a washcoat consisting
of gamma alumina stabilized with 5% by weight BaO and a catalytic
metal layer composed of platinum and palladium. The Pt/Pd
loading was 2.5 g total (Pt:Pd ratio 1:1) on a total catalyst
volume of 84 cubic inches. The results were obtained by
, .
"
. .. , ,,, .. . ... ., . , .. , . . , ~ .,
. . ,
652~7
-15-
driving the automobile through the LA4 diesel cycle. Thehydrocarbons, carbon monoxide, nitrogen oxides and parti-
culates present in the exhaust gas emissions were measured in
g/mile. ~ase line measurements were first taken without a
catalyst in the chamber but with back pressure adjusted to
the same value as with the catalyst present. Results are
given in Table 1:
TABLE 1
Particulates
~IC g/mile ~ ~ /mile~mile
Baseline figures 1.54 1.93 1.53 0.85
Modified engin2 0.214 1.892 0.9790.44
The back pressure was f~und to be high.
"
Example lA
Further experiment~ were carried out using the same
catalyst as in Example 1 above. Baseline particulates
eInissio~s using the same vehicle were determined in four
tests as g/mile figur~s. These were expanded to includc
thermogr~vimetric ~eterminations of the percentage carbon
and volatiles contair.;d within the par~iculates and the
g/mile sulphate contained wi.thin the particulatcs. The
results obta~ned are shown as follows:
. . ,
. _. ,
--` 1165Z47
Baseline fi~ures
Test No... Particulates % Carbon V/o Volatiles ~E~
~/mile . ~/mile
1 - 0.582 62.5 37.S ~.015
' 2 0.512 58.0 42.0 0.011
3 0.509 , 59.6 40~4 0.012
' 4 0.482 61.8 38.2 0.012
N _ : All above measurements cornpleted on a hot LA4 driving
, cycle.
The full baseline emissions determined for '~C, CO ~nd
''~i NOx were also determined, the results being as follows:
, . . .
. Test No. ~ CO ~/mile NOx g/mile
, 1 0.350 1.564 1.775
2 '0.339 1.529 1.803
:,, 3 0.354 1.5~1 1.786
~ , A catalyst c~amber was des.gned wit,hin she constraints
: available in the vehicle without any n.odification being m&de
to the engine compartment layout. This resulted in a catalyst
volume of 0.9 litres which was anticipated to be inadequate
¦ but upon which full tests were completed. The results of
these are as follows:
' ~ .
..
~j .
.
.. . , ., ,,. . , . .. ., , . .. , , . ~ .. . . . .. .,,.. ~.. ..... .... .
-17
Test No. Particulates % Car~ons % Volatiles Sulphate
~/mile /mile
1 0.494 79.4 20.60.036
2 0.441 76.4 23.60.037
3 0.444 75.3 24.70.Q35
4 0.515 67.3 32.70.055
~ 0.466 63.4 3~.60.06
6 0.492 76.1 23.90 051
NOTE: The vehicle had completed 500 road miles prior to the
first test and the entire period of testing was completed
under simulated CitY driving conditions using the LA4 cycle.
Test results obtain-d for the HC, CO and NOx emissions
were as follows:
i Test No. HC ~/mile CO g/mile NOx ~jmile
1 0.22~ 0.979 1.892
2 0.238 1.073 1.874
3 0.215 0.981 2.014
Example 2
¦ A second catalyst chc~ ber as described in the second
embodimel;t (Figure 2) was fitted onto the eng'le. A knitted
mesh support made of the same wire as used in Example 1 again
with a washcoat of gamma aiumina. The catalytic metal layer
-` 1165247
-18-
:
comprises rhodium 7~ wt % and plàtinum 92~ wt %. The total
catalyst volume was 110 cubic inches. The weight of support
used was approximately 1.6 kg, 5 g of washcoat, alumina, and
2.9g of the catalytic metals Rh ~nd Pt in the above ratio
wer~ applied to the support. Baseline measurements were
taken with no ca~a_yst present in the chamber attached to
the engine. The results are given below ir. Table 2 with the
car being driven through the LA4 cycle with a hot start.
TABLE 2
Particulates
H~ ~/mile C0 g/mile NOx ~/mile ~/mile
Baseline figures0 35 1.55 1.8 0.57
1 Modified engine 0.2 0.5 2.1 0.31
¦ The back pressure without a catalyst present in the chamber
was 2.4 inches of mercury and 3.5 inches of mercury with
,,.,~
catal~Jst pr~seLIt ~n the chamber. The C/H atomic ratio of the
particulates present in the exh.~ust gas before and after passage
through the catalyst chamber was measured an~ i.'3 given below
in Table 3 with a hot st~rt for ~he engine.
- 1~65Z47
-19-
TAB-~ 3
C/H ratio of particulates present in the exhaust gas
~efore catal~st After catal~st
i C 63 80
.. j - ,
H 37 20
.l This is a measure of the reduction in the crganic compound
content of the e`xhaust gases. The concentration of sulphate
¦ present in the exhaust gases before and after the catalyst
"~ was measured and found to be unchanged.
Further results obtained are given below in Table 4
;¦ with a cold start for the e~lgine.
T~BLE 4
Particulates
HC R/mile Ç0 ~/mile NOx~ile ~m.tle
Basline figures 0.41 1.3 1.9 0.62
.Modifi~d engine 0.242 0.274 1.86 0.42
. Modified englne 0.218 0.252 1.86 0.4
The com?osition of the particulates present in the exhaust
gas is given below in Tabie S with a cold st~rt for the
engine.
; ,'.
~' ~'" ' ' ' '
' ~ ~
"
.
65247
- 20 -
Carbon Adsorbed HC's
Sulphates g/mile g/mile g/mile
Baseline figures 0.11 0.34 0.165
Modified engine 0.11 0.28 0.025
; 5 The results in Table 2, 3, 4 and 5 were obtained using a
commercially available diesel engine-powered automobile. The
engine had been modified with a catalyst chamber in place as
previously described. The automobile had completed 500 miles
round a test circuit before being driven through the taxi
cycle with a maximum speed of 25 mph.
Further tests were conducted using a commercially avail-
able diesel engine powered automobile. A catalyst chamber as
described in the second embodiment, as shown in Figure 2, was
fitted into the engine. A support was made of 310 stainless
steel wire of diameter 0.01 inch which wa~ flattened to 0.004
inch acro~s before being knitted. The support was coated
with a washcoat of gamma alumina. The catalytic metal layer
comprises rhodium 5.7~ and platinum 94.3~ with a loading o~
25 g/f~ . The weight of wire used was 3,200 g with 1,200 g
of washcoat. The total volume of catalyst used was 217 cubic
inches.
The weight of particulates present in the exhaust gas
was measured by passing a known volume of exhaust through a
- 116SZ47
-21~
`:
dilution tunnel where it was diluted with a set volume of air
to prevent the solids settling before passing the gases
through a filter pad. The weight of particulates enables
a value for the particulates in g/hr to be calculated. The
particulates present in the exhaust gas were analysed further
" ~:
to give thermogravimetric weight, and the weight of volatile
components, hydrocarbons, carbon and sulphate. Using the
above ~ethod a number of filter pads were obtained for analysis.
The weight of sulphate in the particulates was measured by
wet chemical analysis of the particulates. Another sample
was placed in a thermogravimetric balance where the sample
was heated in an inert atmosphere to a temperature of 780~
until the wei~ht was constant. The weight loss between the~
initial weight and the new gives the weight of volatile
components present. Air was introduced and heating continued
~ntil the weight w~ again constant. The difference in this
weight and the value for the previous constant weight gives the
weight o.f carbon components present. The remainder was ash
and non-combustible materials such as iron.
Baseline measurements weré taken with a ma.lifold connected
to the engine in place of the chamber containing the catalyst.
Measurements were taken with the automobile driven through the
' ' . . .
... .
1~5247
.
- 22 -
LA4 cold start diesel cycle are given in Table 6 below,
- LA4 hot start diesel cycle results are given in Table 7
below, and the Highway driving test results are given in
Table 8 below. The Highway test used was the standard
test cycle used in the US for fuel consumption trials.
The results given in Tables 6 and 7 are shown in
graphical form in Figures 5-9, LA4 cycle cold start, and
in Figures 10-14 for the LA4 cycle hot start. ~Baseline
figures dotted line and modified engine continuous line.3
The reduction in particulate concentration (measured
in g/mile) in an I C engine according to the present
invention is shown in column 3. Reduction in adsorbed
hydrocarbon~ and carbond present in the particulates are
shown in columns 7 and 9 respectively. Sulphate figures
show an increase in some ca~es but the absolute level of
the emis~ion remains low.
Back pressure measurements were made. This is the
difference in the pressure of the gases on leaving the
exhaust ports and on leaving the chamber. The results are
given in Table 9 for the automobile being driven through
the LA4 cycle and in Table 10 for the Highway driving
test.
1~5'~4~
.~ _ _ _ . ~
r
~~ ~ ~ ~ J ~ ~
~3~ LC
.N~ ld ~;t ~ u~ J ~J ~ ~ u~
,` ,~ ~ ~ ~ . ' I
~ ~ ~ u~ D ~ ~ O 1
.. , ~ IUI/~ oo ~ ~ ~ r~ ~ O ~ ~ O ~ ~ c~
1. ~ ~ c~ ~ ~ ~ ~ ~ c~ ;~ c~l
NO~ ) . . . . . . . . . . . . . . .
o o o o o o o o o o o o o o o .
-.,~ ,
oo U~ ~ . I
~3N I`d~ I ~ ~ . ~ ~ u~
~19~.1N~ 1 oo ~ ~ oo 1 i~
~ , . I
~ ~ ~ O ~ oo ~ ~,
SNOa~ 0~ ~ C`! ~ O ;l 1~ ~ O ;1-
-O~a~iH C~l O O O O O ~ O O C~l O O O C~ O
~j a~osa~ O O O O O O O O O O O O O O O .
~' . .
--'~ ~ C~ 1 a~
~/~1 ~ )N~ Ia ~ u~ ~ o u~ i ~ ~ _i ~ .
~' ~ a ' ~ $ + + + + + + ~ + ~
o,'' .
~ol . ~ ~ ~ ~ ' ~
~L11 CS~ l u~ tY~ l ~ C~
80 8 o o g ` o o o o ~o o o ~ ~o ~o
vHa~ms O O O O O O O O O O O O O O O
, I
o u~ l a~
~a~ ~ o ~ D
~19~.1N~ I ~ u~ ~ ~ ~ ~ u~
~'~lW~ ~D ~ ~ O ~ ' c~l ~ ~ ~D ~ ~
. ~ oo ~ C5~ ~D ~ O ~ O
n~ 1 ~ ~ ~ ~ ~ ~ ~ ~
~,10.1.o o o o o o o o o o o o o o o
~ .~ rl ~ ~ . ~ ~ .~
. :~ 1 t~ ~ G 0
. ' . , . O 'O
S ~ I O o ~g ~1 ~ ~ ;t ~ O O g o O o l
-Z- -
.
, ._
` _ _ ~ _ _ _
. .
~ I~ a~ ~ ~ ~ I~ I~ O ~ ~D
'~N~ Ia ~ oo ~i ~ u~ ~i o ;i ~D~ O
~ N~ a ~ ~ ~ ~ ~
:;, .
;~ C~l U~ .
`;t J ~ ~ ~ ~ ~ ~ o~ ~ r~ ~ ~9 ~o
aTIw /~ ~ ~ 1 ~ ~ o
. / ~ ~ ~ l
NO~ ) o o o o o o o o o o o o o o o
. '~
, . . .
~: ~ ~ ~ ~ u~ r~ I~
., ~?N~ I a ~ ;
~3~a 00 co 00 ,,
. .
.
c~ u~ ~J ~ O~ .
. ' O ~ ~D ~ C`l O O 1~ 0 u~ O `D cr~
SNoa~
o aAH ~ o o o o o ~ o o ~ o o o ~ o
¢l a~osa~ o o- o o o o o o o o o o o o o
~! ~1
, ~ o i~ ~
, ~ )N:I~ldd~Ia ~ ~ o ,~
' ~ )YLN'd:)~Ida ~ + + + + ~ ~ ~ U~ ,
~j .
;~, c~
1 O ~ D ~ _l ~ u~
I co ~g 1~ 1~ ~ u~ ~ C~l ~ cr o~ I~
~, O O O O O ~ ~ ~ ,~ ~ ~ ~ ~_, _,
~, ~ O O O O O O O O O O O O O O O
~a~n~ o O O O O O O O O O O O O O O
oo ~ O ~ _l
d~ dI a ~, ~, 00 ~ Ln ~O O ~ ~ ~ Ln ll
~ J,Nd~ ad Ln ~ Ln ~o ~ ~ Ln u~ ~ n ~ ;~
~ ~ ~ ~ oo n _I ~t ~ ~ a~ ~ ~ oo ~l ~
~O _I ~ O _I O 00 ~ ~ C~J ~O 1~C~l 00
n~ a L~~ ~ Ln C~ ~ ~
~d~O~ o o' o o o o o o o o o o o o o
, ~ ~ .~ ~ ~ a
~d ~ ~ ~
~ ~ ~ ~ o o
o o o o o o o o o o o o
o o o o o o o o o o o Ln n
S~ I o c~ o~ o ~D ~ cs~ _I n ~ Ln
O O ~D ~ ~ ~ ~ ;~ ~ n n ~ _I _
.. __ ___
_~z _
.
1~6S29t7
_ . ~ __ , ~ ~ _ _ _ ~
'~9N~ I Cl oo ~ u~ ~D
~ N~13~I~la l ~ ~ ~
. . , ~ ~ .' ,.
a~ _~
allw /~ ~ c~l o ~ ~D ~ ~D ~
NO~ ) o o o o o o o o
~ .
. o ~ U~ ~
,
,,.~ ~3N~ ... a . . . . .
'-'' ~ N~ a ~D ~O u~ u~ ,~
f~'
~D C~ ~ 1_ ~ ~ O 0~
~, sNoa~ 2 o ~ ~o ~ o ~ o
,~, -o~a~H o o o o o o o o
~i a~a~os~ ~
~;j ~D O. ~ L'~ ~ j
~I~)N~ I(1 ~ ~ ~
~9~N~3~ [ + $ + -t .
Sl C~ I~ ~D ~ _l .
~! i 3 ~ ~U1/~3O O O r~l O O O
i5~ ~ lRmS~O I 11 1l 1l
~NOI~ la ~ ~ O O
~19~N~13~1a.~ $ . _1 . ~ '.
I
~ ~ u~ ~ ~ ~O ~ c~J ~
oo ~9 u~
T~OI, o o o o o o o o
_1 ~a _1 .1 ~ ,/j q~ ,Cj j ~
: ~ ~ ~ ~ ~ ~ ~ X ~ ~ ~ ~ .
o o
S~ o~ o o~ 1n u~
o _l ~ ~ 00 0~ _1 ~
_5Z _
5Z47
-26-
TABLE 9
Back pressure in inches of mercury
Miles covered Baseline After catalyst chamber
~ex. Avera~e Max. Average
Hot Start
0 3.12 0.63 2.88 0.75
1,800 3.42 1.0
4,200 3.8 0.98
4,900 3.67 0.91
5,500 5.35 l.9
6,100 2.42 0.65 4.58 1.43
8,500 3.31 0.96
12,5~0 2.38 0.85
Cold Start
0 2.64 0.48 3.54 0.86
1,8~0 3.15 1.15
4,200 4.6 0.96
4,900 4.5 0.95
5,500 4.86 1.65
6,100 4.84* 0.61 ~.62 1.38
8,500 3.28 0.96
12,500 2.5 0.83
HiL figure probab1y ue to build up of soot deposits
. . .. , . .. .., , ., .. .. , ... . , . .. . . . ., , ., --
. .
5Z47
-27-
TABLE 10 `
,~,
~ Back pressure in inches of mercury
Miles covered Baseline After catalyst chamber
Max. Avera~e Max. Average
1,800 3.34 1.98
- 6,100 2.0 1.1 4.05 2.9
8,S00 3.12 2.0
TABLE 11
Back pressure in inches of mercury
Miles covered Baseline After catalYst chamber
Max. hvera~e Max. Avera~e
0 2.88 0.56 3.20 0.80
. , ,.
8,500 ~.48 0.61 '~.62 1.38
'
,
,, .
' .
, ' '
,
1 , ,
'~ '
.~'
.
;SZ47
-28-
In the foregoing description the following abbreviationshave 4een used and their meanings are indicated.
CVS - constant volume sampling.
LA4 - Los Angeles Cycle as laid down by the Environmental
Protection Agency (EPA) and the United States and is a
standard test cycle devised to simulate a drive to work
in Los Angeles traffic conditions. It is furthermore a
test to which all new vehicles are subjected.
Taxi Cycle - A test cycle of about SO miles l~ng approved
by EPA and carried out at low speeds up to 25 m.~.h. and
includes periods when the cal is stationary and the engine
is idling.
'
