79-10
Evaluation of Restorative Maintenance and Catalyst
Replacement on Exhaust Emissions from Eight Very
High Mileage Passenger Cars in St. Louis
June 1979
by
Gary T. Jones
Technology Assessment and Evaluation Branch
Emission Control Technology Division
Office of Air, Noise and Radiation
Environmental Protection Agency
-------
Abstract
This report describes the results of an exhaust emission testing program
on eight catalyst-equipped passenger cars in the St. Louis area.
Vehicles from each of the three major domestic manufacturers were pro-
cured from the general public. The vehicles were sought to obtain a
general representation of popular models and engines with the final
selection based on odometer reading. The vehicles chosen were from the
1975 model year and averaged 104,479 miles with a range from 71,026 to
138,831. The test sequence included the exhaust emission portion of the
1975 Federal Test Procedure, the Highway Fuel Economy Test and three
short cycle tests/ This sequence was employed five times over two
phases. The first phase consisted of test sequences in (1) as-received
condition, (2) after correction of maladjustments and disablements of
emission control systems, and (3) after a complete tune-up with replace-
ment of defective parts. The second phase provided for two test sequences;
one after the existing catalyst was replaced with a plain section of
pipe (with restrictions to duplicate back pressure) and the other after
installation of a new OEM catalyst.
The results from the first phase indicate that high mileage vehicles
generally exhibit higher HC and CO emission levels than their counter-
parts with lower mileage which were tested in earlier Restorative
Maintenance programs. The results from the second phase appear to
indicate a loss in catalyst activity with age and mileage when compared
to the activity of a brand new unit.
Introduction
For the purpose of Federal Regulations which pertain to motor vehicle
emissions, "the useful life" of a vehicle has been defined as 5 years or
50,000 miles, whichever occurs first. Prior EPA surveillance studies of
passenger cars have demonstrated that even low-mileage, relatively new
vehicles exhibit poor average emission performance when compared to
applicable standards (Reference 1). These studies went on to determine
that maladjustments and disablements within the emission control system
(primarily idle mixture) were the primary cause of the problem. Signi-
ficant reductions in average levels were possible once these actions
were corrected.
Recently, there has been an increased interest in the possibilities of
Inspection/Maintenance (I/M) Programs on in-use motor vehicles as a
major tool in controlling air pollution. When this interest is combined
with the fact that many of the first catalyst-equipped vehicles have now
exceeded the 50,000 miles of this "useful life", it is clear some assess-
ment of these vehicles must be undertaken to project their impact on air
quality.
-------
Program Design
The purpose of this effort is to gather information on catalyst-equipped
passenger cars which have exceeded their defined "useful life". The
following areas were to be addressed:
1. Emission performance in as-received condition.
2. Extent of malperformance in the emission control system.
3. Capability of restorative maintenance in reduction of emission
levels.
4. Effectiveness of both old and new catalysts on emission levels.
A total of eight catalyst-equipped passenger cars were procured from
private owners in the St. Louis area. Vehicles of each of the three
major domestic manufacturers were chosen to constitute the test fleet.
The actual vehicles were sought to obtain a general representation of
popular models and engines with the final selection based on odometer
reading.
Each vehicle was subjected to a prescribed series of tests, inspections
and maintenance actions. The flow diagram for this effort is attached
as Figure 1. The basic test sequence conducted at each point included
the current Federal Test Procedure (exhaust emissions only), the Highway
Fuel Economy Test and three short cycles (Federal Short Cycle, Two-Speed
Idle and Federal Three-Mode). The initial test was performed in as-
received condition. This was followed by an underhood inspection and a
correction of all maladjustments and disablements. A second test was
performed with the vehicle in this condition. The third test was preceded
by a major tune-up and replacement of any defective parts. This phase
of the program would serve to address the first three aspects of the
listed purposes. The last aspect would be addressed by the elements in
the second phase.
The fourth test on each vehicle was performed to obtain "engine-out"
emissions. The original catalyst was replaced with a section of plain
pipe after measurements of exhaust back pressure had been recorded under
a range of steady state conditions. The back pressure was duplicated as
nearly as possible by introduction of a device which was tailored to
restrict exhaust flow at the tailpipe. For the fifth and final test, a
new OEM catalyst was installed. The original catalysts were retained
and are being throughly examined and analyzed under a separate effort.
Inspection Results
After the first "as-received" test sequence, each vehicle received a
thorough inspection for maladjustments, disablements and defective
-------
-3-
emission control components. As in earlier Restorative Maintenance
programs, the most common disablement was broken or missing limiter
caps. Only one vehicle had its limiter caps present and unbroken. This
vehicle was also the only vehicle to pass Federal Standards "as-received".
The second most common disablement was plugged or disconnected EGR
vacuum lines. This disablement was found on three vehicles. Rich idle
mixture on half of the test vehicles accounted for the most common
maladjustment which may be slightly lower than expected considering that
all but one vehicle had missing or broken limiter caps. Two of the test
vehicles had defective vacuum breaks (leaky diaphragms). There were
many other defective parts found and replaced, but no single part was
prevalent in frequency of failure. The majority of these parts would
not have had an adverse affect on driveability and consequently would
not have likely been repaired by the vehicle owner.
Phase I Test Results
The results of the first phase of testing show the improvement in emis-
sion performance that has been witnessed in past Restorative Maintenance
programs. Through correction of maladjustments and disablements, all
three regulated emissions were reduced. Average HC emissions were
reduced 32%, average CO emissions were reduced 55% and the average NOx
emissions were reduced 22%. As has been the case in past programs, idle
mixture adjustments were found to have the greatest impact in reducing
emissions. This can also be seen in the improvement of idle CO which
decreased from an average of 2.02% to .06%. Although the major tune-up
performed prior to Test #3 reduced the average CO 21% from Test #2 on
the FTP, the average HC increased slightly (9%). NOx remained essen-
tially the same. Through Test 1, 2 and 3, the percent of vehicles
meeting Federal Standards was 13%, 38% and 50%, respectively. These
percentages are displayed graphically in Figures 2 and 3.
Phase II Test Results
Preparation for Test #4 consisted of removing the catalyst and replacing
it with a plain section of pipe. Before removing the catalyst, the
backpressure created in the exhaust systems of the test vehicles by the
catalyst was measured by a water manometer at a point just before the
inlet of the catalytic converter. These measurements were taken at idle
through 60 miles per hour in 10 mile per hour increments. After re-
cording these measurements, the catalytic converter was removed and the
plain section of pipe was installed in its place. An adjustable orifice
was then introduced into the exhaust system at a point near the end of
the tailpipe. The backpressure was then measured at the same point in
the system as it was earlier. The aperture of the back-pressure dupli-
cator was varied until the pressure matched the earlier measurement (plus
or minus 2 inches of water). As expected, the average HC and CO emis-
sions increased from the averages shown in Test #3. HC showed the most
dramatic increase (87%) over Test #3, and was considerably greater (36%)
-------
-4-
than the "as received" emission values. The average CO emissions were
only 59% of the "as received" values but were 66% greater than the Test
#3 average values. NOx displayed a decrease of 5% from Test #3. Under
the Test #4 conditions, none of the vehicles were able to meet Federal
Standards. Test #5 consisted of removing the backpressure duplicator
and the plain pipe section and replacing it with a new catalyst. Test
#5's average emission results were lower than any of the previous tests
for all three regulated pollutants. The average HC emissions in Test #5
were 27% of those recorded in Test #4 and 37% of the "as received"
values. Average CO was 57% of the Test #4 value and 34% of the "as
received" average CO emissions. The average NOx emissions were 84% of
Test #4 values and 61% of the "as received" values. The new catalyst
obviously had a significant impact on reducing emission levels. This
completed the vehicle testing sequence. No subsequent tests were per-
formed on these vehicles once the new catalysts had accrued some mileage.
Conclusions
The results show that these high-mileage vehicles had significantly
higher average emissions "as-received" than similar vehicles with lower
mileage tested in an earlier Restorative Maintenance program. In this
condition, only one of the eight vehicles was able to meet Federal
Standards. However after the correction of maladjustments and disable-
ments along with a major tune-up and replacement of defective components,
HC and CO levels were reduced and half of the test vehicles were able to
meet Federal Standards. The test after removal of the original catalyst
showed evidence of its activity because of the emission increases
witnessed. The installation of a new catalyst showed that although the
old catalyst was still working, it was not up to the efficiency of the
new one. But even with new catalysts installed, only 63% of the vehicles
meet Federal Standards. This indicates that even though an individual
high-mileage vehicle is tuned-up and a new catalyst is installed, it may
not meet the standards under which it was certified. On the other hand,
the average results for the fleet display some durability of emission
control systems and the ability of such vehicles to respond favorably to
proper maintenance.
-------
-5-
References
1. J. T. White, "An Evaluation of Restorative Maintenance on Exhaust
Emissions from In-Use Automobiles", SAE Paper 780082, March 1978.
-------
Figure 1
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St.
Flow Diagram
Louis
OBTAIN
^VEHICLE,
[TEST//1|
1
EMISSION COMPONENTS
MALADJUSTMENT/DIS-
ABLEMENT INSPECTION
CORRECTION
OF MALADJUSTMENTS
AND DISABLEMENTS
ANY
MALADJUSTMENT
OR DISABLEMENTS
FOUND?
NO
MAJOR TUNE-UP AND
REPLACEMENT OF
DEFECTIVE EMISSION
CONTROL COMPONENTS
<
frEST//3J
REMOVE OLD CATALYST
AND INSTALL BACK-
PRESSURE DUPLICATOR
JTEST//AJ
INSTALL NEW CATALYST
AND REMOVE BACK PRES-
SURE DUPLICATOR
{TEST// s|
/RETURN VE
HIC1.E T0\
OWNER /
-------
Figure 2
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
Average Mileage:104,479
HC
CO
NO,
4.0
3.0 -
3.56
.2.61
1,78
1.94
,Federal Standard= 1.5 grams/mile
a
°° *" Q7
1.0 J -y7
0 *
12345
• Test Number
35 1 33.2
30 -j
25 -I
3 20 J *•! -I 19.7
B
/Federal Standard =15 grams/mile
s _L_i j!5.0 J I jf
* 15 4--I 1 . 1--4 •*
11.9 I 11.3
10 H
5 .
0 -
12345
Test Number
4.0 -i
3.32 /Federal Standards 3.1 grams/mile
3-° * „ c_ Test 9 Action performed prior to test
5 i 2.53 •) L")
•H 2.58 i ? , 1 None,tested "as received".
~«2.0 \ | 2 All maladjustments and disablements
corrected.
[_Q . 3 Major tune-up and the replacement
of'defective components.
4 Replace catalyst with non-catalytic
0 ^ , 2 .j ^ 5 back pressure duplicator.
Test Number ' 5 Install new catalyst.
*Note: Dotted lines represent fleet average emissions of 300 1975 and 1976 Restorative Maintenance
Vehicles tested in a earlier program (Reference 1).
-------
Figure 3
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St.Louis
Average Mileage:104,479
IHC
(ppm)
400
300
200
100
437
*."130 •:
145
80
234
Test Number
127
%ico
2.0%,
1.5%
1.0%-
2.02
0%
.59
234
Test Number
.26
% Passing
Federal
Standard
80%-
60%-
40%-
20%
63
*Note: Dotted lines represent fleet average emissions of 300 1975 and 1976 Restorative
Maintenance Vehicles tested in a earlier program (Reference 1).
-------
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
Veh.#57l Odometer /38,g3\ Makef^W. Model P**>W CID_£2jT_ Garb I' Trans_J RLHp ll'-Z- Inertia 3500
Test-? Date
/
I
3
H-
Z
|0 -\0-78
10-12.
ID-IS"
/o-jg
lO'to
FTP (gin/mi)
HC CO NOX
3, £2
l,7t
3,00
3.15"
l.tf
¥T.3
/AS
22<\
2C/^
20,1
2 ,77
3.T7
2,5*1
2, 10
7,3*.
MPG
FTP HFET
/7-82
/^34
/?, //
/S.2H
/7ff
26.99
26-/6
24-^
26.4^
ZSM
IHC ICO
(ppm) (%)
HO
2<1
557
610
6fcl
1-.H3
,0|
.ai
/,67
.^
Comments
o^ps m\s£.iNtr
IDut 5TOP SotCiMioo DtFtcTiM^c
AD^JST /Oi-£ milTv&K:
roMofc. TO Nit \;P
IDLt STO-P SOLCMoiD ^tpLACcD
CAt/li-YSr ^LPtA^Co tourt ey-PASS/
foeto cAT^usS'T iN^T/ALtro
Test // Action performed prior to test
1 Hone,tested "as received".
2 All maladjustments and disablements
corrected,
3 Major tune-up and the replacement
of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
HC
1975/76 Federal Standards: 1.5
(grams/mile)
15
NOV
3.1
-------
Veh.// 572. Odometer 75" 06^ Make
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
Model Ovvrag y- CID_3kO_ Garb £ >/ Trans A RLHp / £ . 7 Inertia
Te :-•.-* Date
/
I
3
t
5"
/0-<7~7£
AMZ
/^•J3
/o-lg
fO-2.0
FTP (gm/mi)
HC CO NOX
4,34
2-14
3.?^
^.^77
.13
77. 7
fi.O
/^.^>
/6.S
2I.8
3.29
^/.//
2.0^
A7?
.67
MPG
FTP HFET
13*7
13,33
li.O?
72.01
11.17
2/./6
20.(,3
/C* />\6'
/£» L-'O
y £) J_L/
/ /' *C?
/7-«
IHC ICO
(ppm) (%)
270
65-
726
-/jq-
*n
Test ?/ Action performed prior to test
3, S3
.06
,02
.20
,%
1 None, tested "as received".
2 All maladjustments and disablements
corrected.
3 Major tune-up and the replacement
" of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
Comments
CAP5 hrMiStNt? ^ EfoR. vJAt-uu/A u\Nt O\ CQ
'TlftitHC? AOjvS~iCDi /^Ip. Ci-C/1AJC(2. Tof CoRf2,CC-"PcO.
PlA^OPx "TUtvi^e Up
CA'fAL^ST ^vt^UA^t-D wiT"^ (^y-I^AS-S.
A)^ CATAU^ST /A»S-TALueD
/
•
HC CO NOX
1975/76 Federal Standards: 1.5 15 3.1
(grams/mile)
-------
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from EightVery High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
Veh.i1/ 5)3 Odometer 7\C)Z(0 Make PJ'y^ Model Sfe.. C4u,. CID 318 Garb 2 V Trans A RLHp /HV7 Inertia
'J'fsi-7 Dace
/
I
3
t
5"
IO-I2-7S
jO-H
1017
10- ft
10-20
FTP (gm/mi)
HC CO NOX
.65"
A/Z
•'W
/.£&
.62.
£3
2'6.5"
V>6
2ZS
/y-.f
7-34,
/.75
2.12.
/,78
A 3»-
MPG
FTP HFET
IJ.IU
II -Cg
II'U
ll-tf
ll.tf
/9,00
/5T5&
/5TZI
16.10
i^m
IHC ICO
(ppm) (%)
G7
jr
31
/2fc
2Z
,04-
^o^
.02
A55"
,02.
Comments
CAPS miss/M6-y OSAC VALME eypAs's e:o,"6fel> x^ ^^R-
VAt-ou^v uiwc, riC. DEJ=Et-~rKC
OS AC. OC/JNe^TtD,
"06V> ^.CrvNovieo Fi2.c\m gTfcR. vAcuo/v\ UIMF
VnAvioB. T^fOt U fj
p,epwu-eo r\c .
CATALVST (2>tP\,Aei?o vO \TY> ^ ?F\$S>tt>
/JEW C.ATAL7ST ^AJSTfc t L i?O
Test 7^ Action performed prior to test
1 None,tested "as received".
2 All maladjustments and disablements
corrected.
3 Major tune-up and the replacement
of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
HC CO NO
1975/76 Federal Standards: 1.5 15 3.1
(grams/mile)
-------
Veh.ff 524 Odometer
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
7 Make t^e^O Model POc'ttciToVs CID25O Garb Jv Trans ffl-3 RLHp_/_21O_ Inertia
Test-- Date
/
2.
3
?
f
*?-2K-7g
9-2*1
10-Z.
ic- 5
IC-JI
FTP (gm/mi)
HC CO NOX
/,%>
US'
1.51.
2.0A^oiV TuMfc vq
CATALYST pstfLACCO ^ »TH 6>-fA^&
jOttj OATAUYST ^STALLED
Test // Action performed prior to test
1 None,tested "as received".
2 All maladjustments and disablements
corrected.
3 Major tune-up and the replacement
of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
HC CO NO,
1975/76 Federal Standards: 1.5 15 3.1
(grams/mile)
-------
,.// 526 Odometer/]/. 5"/2- Make
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Sight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
Model /-TP C1D 35V Garb £ V Trans /A RLHp / *f• 7 Inertia
•
Test-'-' Date
/
2
3
?
. ^
c/-3^
fO-2
10-7
10-10
/O'l)
FTP (gni/mi)
HC CO NOX
3.2$
3.2L7
2. Of
2.8*
2,05"
20. |
a3,t
//.o
/O. 3
s,o
dT.fcfT
3.7)
63^
O> 7^3
6> ti\
MPG
FTP HFET
lo.y
//.oa,
/I-63
//.73
\}M
16.&I
frt*
11,. %
lb.5\
/7- /^
IHC ICO
(ppm) (%)
7^
£t
/3^
2/1
20^
.37
• 3fc
,or
,oa
• 03
Comments
CAPS VniSSlAit9, E6R. fLu^rGfEDy AIR. P\iS JXfE^"1"* pcu^y VC.o^l-tLy
H,A.D. SEN3OQ. DCfr£t-T»>/ e (t*>lLL MCJ ' •Av"u L AW.VJ»V\ ^
Puub M«»«W r»»m e«^.«Ac-v..«v ^»e.
ANO A((2_ p\yS,
CATAuyST RC(pUi.Cc.O uilTH BY- PASS
N£u> CATAW5T- /K)STAU.£D
Test # Action performed prior to test
1 None, tested "as received".
2 All maladjustments and disablements HC CO NOY
corrected. 1975/76 Federal Standards: 1.5 15 3.1
3 Major tune-up and the replacement (grams/mile)
of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
-------
Odometer
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
U^ \ Make C\r\f^. Model SjcOtX CID £S'C* Garb / v Trans A RLHp //. 2- Inertia 3S<-
lost-- Date
/
2
3
4
30.^
S.I
7,5-
?./
5:^
/.f^
/.2.^
A/7
/ 2T
/.05
MPG
FTP HFET
IL> . b'/
/^.^
/7fo7
!$.-!> 6
1^1
23. 31
2?.Sf4-
2|.7t
22.0^
22.2.3
IHC ICO
(ppm) (%)
/76
77
sv-
S^
0
2.5^1
-01
.01
,12
.01
Comments
CAP5 rniSS'^Or, t't-JL. 'MACo^vn LiNt ^i'ViT^
f (^ m AP>V v A Cv^ ,v\ 0^> ZA p. t-EA KV
iPi.i? rn/XTt'&E /\£>J^sreP
fHAjcR. TvNJt L'P/RtpLACeo ECr-p. v/'AC-c*- ,y\ /-/^E"
P^ef-uAt to PfMmAp-y \jAcov.' rrx G^tAK.
C-ATAi-V^'T fiCPuAc-CO U'iTn fc> ?AS3
/Mtto CAFAUNSr )N3TAU,E-p
Test ^ Action performed prior to test
1 None,tested "as received".
2 All maladjustments and disablements
corrected. \
3 Major tune-up and the replacement
of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
HC CO NO,
1975/76 Federal Standards: 1.5 15 3.1
(grams/mile)
-------
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
Veh.#.53B Odometer JO7 °\ 7*7 Make CheV Model {V\cx\\b^>- C1D 35~O Garb ^v/ Trans A RLHp
Inertia
Test" ' Date
2
3
4-
S
(0-2X-1&
JO 15
/0-30
//-I
J/-3
FTP (gm/tni)
HC CO NOX
*.i*
/.^
1,^0
^.0"?
.tfl
70. (?
)3-7
/23
ZI.O
74-
1.82,
Z.33
i.sz
IA2.
)-T?
MPG
FTP HFET
/3.CO
Ittf
/3X>5
I2.U,
U-36
tf.S3
20.4-1
l*.Sfl
/*.!*
/^
IHC ICO
(ppm) (%)
Z3) 9AS5
K1G.U) CATAV-^T IMSTAti-eO
HC CO NOj.
1975/76 Federal Standards: 1.5 15 3.1
(grams/mile)
-------
eh.4 539 Odometer 1 37, 75 I
Evaluation of Restorative Maintenance and Catalyst Replacement
On Exhaust Emissions from Eight Very High Mileage Passenger Cars in St. Louis
-Vehicle Test Results-
C1D 35"O Garb W Trans A RLHp /f-O Inertia
Model
'•'•.• ' t- Caic:
/
;3
i
5
Jo-2^-1%
|C-lt?
(0-2.7
J0~2.cj
FTP (£n/mi)
i;c " co NOX
/•20 r?,l
Ml /M
2.3) 21.6
ll'l
1*7
i,$b
/.^
MPG
FTP HFET
11,01 /$tfl
12.^1 /S.37
//.^l y?,^
//.88 /6.^
IHC ICO
(ppm) (%)
67
45
Zoo
11
Test •/ Action performed prior to test
0-0
.01
.13
.ol
1 None, tested "as received".
2 All maladjustments and disablements
corrected.
3 Major tune-up and the replacement
of defective components.
4 Replace catalyst with by-pass.
5 Install new catalyst.
Comments
^e^Tj&VACXw'\r!^ fFt" VACl"'B1
^ • • i
tnpvA-i.c'SJ- T"^ Ni& u P
CATALYST ft.clPUAC.ED w\Tw ^ -?>A^
wCUJ ^-A-ffsuNST troSTALu-tCs S
o
CM
^H
1
p-l
in
vO
1
O
CO
HC CO NOV ui
1975/76 Federal Standards: 1.5 15 3.1 I
(grams/mile) o
o
P
i
Ul
2
(C
Ul
I
O
«i
3
«
------- |