A/C No. 17F
Unned Sia:es Off ice of November 16, 1982
Environmental Protection Air. Noise and Radiation Paee 1 of 17
Agency Washington. DC 20460
&EPA QMS
Advisory
SUBJECT: General Criteria for the Carryover and Carry-Across of Certification
Data and the Carryover of Fuel Economy Data for Light-Duty Vehicles
and Light-Duty Trucks
I. Purpose
The purpose of this advisory circular (A/C) is to set forth EPA's policy
regarding the use of certification data in more than one category or
subcategory of vehicles of the same model year (known as "carry-across") and
the use of data from previous model years' certification vehicles (known as
"carryover"). A/C No. 17E is superseded beginning with the 1983 model year.
II. Background
A. General Background
40 CFR 86.082-24(f) provides that the Administrator may accept data
from a vehicle for which certification has previously been obtained or for
which all applicable data required under Section 86.082-23 have previously
been submitted and which is similar to another emission-data or
durability-data vehicle selection. This provision is the basis for carryover
and carry-across and permits manufacturers to obtain certification without
unnecessarily incurring the costs and delays of building and testing
certification vehicles.
B. Recent Revisions
1. Although some interaction between evaporative and exhaust
emission levels is likely, the amount of interaction is not expected to be
large enough to significantly affect the deterioration of exhaust emission
control systems. Therefore, the evaporative emission family and control
system restrictions of.A/C No. 17E, paragraphs VI.A.3.b and c, have been
deleted.
2. EPA initiated the voluntary Abbreviated Certification Review
Program in a letter to manufacturers dated December 15, 1978. In Attachment A
of the letter, EPA said that manufacturers may decide in lieu of the
Administrator the appropriateness of using emission data from previously
certified vehicles to represent test results of similar emission-data and
durability-data vehicles in lieu of testing said vehicles. The abbreviated
certification review program procedure was formally adopted in 40 CFR
86.080-12 on April 17, 1980. Manufacturers have been routinely making their
own carryover decisions, subject to EPA audit, since that time.
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3. In order to facilitate the efficient carryover of durability
data based on equivalence or superiority, a list of vehicle differences and
specific data requirements has been added to Section IX. This will allow
manufacturers to approve durability carryover based on equivalence or
superiority in certain limited situations.
4. EPA policy concerning test weight intervals was established in a
memorandum to Certification Branch members dated April 24, 1979. The
memorandum stated that emission-data carryover would not be jeopardized if a
vehicle had been tested at a higher test weight in a previous year and the
request for carryover was to represent a vehicle at a lower test weight. The
inertia weight class restriction of A/C No. 17E paragraph VI.A.4.d has been
deleted to reflect'this policy.
5. On September 25, 1980, EPA published regulations in 40 CFR
86.084-28(b)(4) that allow manufacturers to design their own testing
procedures for determining emissions deterioration factors for light-duty
trucks starting with the 1984 model year. Under these regulations, the
manufacturer is responsible for determining the applicability of carryover of
deterioration factors for light-duty trucks. As in the past, carryover
guidelines established for light-duty vehicles may be used by the manufacturer
for light-duty trucks where applicable.
6. EPA sent a letter to manufacturers dated July 1, 1981 which
contained Certification Program Policy Changes including several changes to
A/C No. 17E. Paragraph VI.A.S.d was changed to allow equivalent test weight
to increase by 500 pounds for durability-data carryover. Paragraph VI.A.S.f
was deleted to remove the road-load horsepower constraint for durability-data
carryover. Paragraph VI.A.5.b was changed to allow emission-data carryover of
back-to-back running change testing. This A/C has been revised to reflect
these policy changes.
8. On October 13, 1981 EPA published regulations in 40 CFR
86.082-26(a)(3)(i)(A) and (ii)(A) that allowed emission-data vehicles to
accumulate more than 4,250 miles but required the fuel economy data to be
factored after 6,200 miles. Paragraph V.A.6 of this advisory circular was
added to ensure that any data generated by a fuel economy data vehicle which
was carried over to fulfill emission-data requirements would also be factored.
III. Applicability
This advisory circular is effective immediately and is applicable to
1983 and later model year light-duty vehicles and light-duty trucks.
NOTE; To avoid repetition of phrases such as "prior model year,"
"current model year," and "year for which certification is sought," general
applicability references are made to model years 1982 and 1983. These
references do not limit the applicability of this A/C. In applying this
circular to other model years, 1983 shall be considered to have the same
meaning as "year for which certification is sought," and 1982 to mean "year in
which carryover data were generated," or "prior model year."
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IV. Relationship Between Emission Data Carryover and Fuel Economy Data
Carryover
A. Although the carryover of certification data is treated separately
from the carryover of fuel economy data in this A/C, the approval of fuel
economy data carryover depends on the acceptability of emission data
carryover. Conversely, in some cases, emission data carryover may not be
approved in light of information obtained while generating new fuel economy
data. For these reasons, neither emission data carryover or fuel economy data
carryover will be approved nor denied until the acceptability of both of these
sets of data is determined.
B. In general, three conditions can exist relating to emission data
carryover and fuel economy data carryover, as follows:
1. If both emission data and fuel economy data carryover criteria
are met, emission data and fuel economy data carryover will be approved.
2. If emission data carryover is found to be unacceptable, neither
emission data nor fuel economy data carryover will be approved.
3. If the emission data carryover criteria are met, but the fuel
economy data are found to be unacceptable for carryover, fuel economy data
carryover will not be approved and new fuel economy data will be required.
Emission data carryover will not be approved at this time. If the new fuel
economy data are acceptable and and the fuel economy data vehicle meets the
1983 emission standards, emission data carryover will be approved.
C. A flow chart depicting a general carryover evaluation procedure is
attached to this A/C.
V. General Criteria for Carryover of Exhaust Emission Data
A. An initial determination as to the acceptability of the proposed
carryover data will be based in part on such considerations as the similarity
of test results between the manufacturer's and EPA1s facilities, special
problems, or marginal emission performance encountered during 1982
certification. The ultimate determination will be made as follows:
1. The 1983 certification test vehicle selection will be designated
just as if carryover had not been requested.
2. The test vehicle selection for 1983 will be compared with the
vehicle which generated the proposed carryover data.
3. Carryover durability data will be accepted if the 1982
durability-data vehicle:
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a. Qualified to be grouped in Che same engine family! as the
durability-data vehicle designated for 1983—vehicles not qualified to be
grouped in the same family may be evaluated under the provisions of Section IX,
b. Was equipped with the same exhaust and crankcase emission
control systems as the durability-data vehicle designated for 1983—vehicles
not equipped with the same control systems may be evaluated under the
provisions of Section IX,
c. Was tested at the same, heavier, or no more than 500 pounds
lighter equivalent test weight as the durability-data vehicle designated for
1983,
d. Was generally representative of the durability-data vehicle
which was designated for 1983 model year certification in terms of other
parameters judged to be significant by EPA (e.g., engine displacement,
auxiliary emission control devices, etc.),
e. Had interpolated test results which could comply with the
provisions of 40 CFR 86.082-28, and
f. Had all emission-related scheduled maintenance items
performed at the same or less frequent mileage interval as is scheduled for
the 1983 vehicles for which carryover is sought. Maintenance items which were
scheduled to be performed on the 1982 vehicle on an "inspect and perform if
necessary" basis, but were not performed as a result of the inspection, may
generally be eliminated from the 1983 maintenance schedule (if justification
is provided) without jeopardizing durability carryover. Less frequent 1983
model year maintenance also may be approved if the manufacturer demonstrates
that such maintenance results in equivalent or superior emission control
performance (see Section IX).
4. Carryover emission data normally will be accepted if the 1982
emission-data vehicles
a. Qualified to be grouped in the same engine family-'- as the
fimission^data vehicle designated for 1983,
b. Qualified to be grouped in the same evaporative emission
family^ as the emission-data vehicle designated for 1983—vehicles not
qualified to be in the same evaporative emission family may be evaluated under
the provisions of Section IX,
c. Was equipped with the same exhaust, evaporative3, and
crankcase emission control systems as the emission-data vehicle designated for
1983,
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d. Was tested at the same or heavier equivalent test weight and
had the same transmission configuration (i.e., manual, automatic,
serai-automatic, number of forward gears, overdrive [if used during FTP],
torque converter multiplication ratio, stall speed, and shift calibration) and
N/V ratio (within three percent in any of the forward gears),
e. Used a shift procedure which, for any upshifting sequence
(e.g., shifting from second to third), differs by no more than 3 raph from the
shift procedure recommended by the manufacturer (in accordance with 40 CFR
86.128-79) for the emission-data vehicle designated for 1983 (see paragraph
4.d, above),
f. Differed from the emission-data vehicle selected for 1983
nnly in ways (e.g., calibration differences) in which, in EPA's technical
judgment, would cause the 1983 vehicle to have equivalent or superior emission
characteristics,
g. Had a road-load horsepower value of at least 90 percent of
that road-load horsepower setting designated for the 1983 model year, and
h. Had emission test results which would comply with the 1983
standards after the applicable deterioration factor has been applied.
5. Carryover of data from running change vehicles will be accepted
if the running change vehicle meets the criteria of paragraph 4 above.
6. Carryover of data from fuel economy data vehicles to satisfy
certification emission-data requirements will be accepted if:
a. The vehicle meets the criteria of paragraph 4 above, and
b. The fuel economy data has been factored according to 40 CFR
86.082-26(a)(3)(i)(A) and (it)(A). (If the data has been previously submitted
unfactored, it should be factored and resubmitted as a new test.)
B. If, based on the above criteria (including the initial determination
regarding the acceptability of the proposed carryover data), exhaust emission
carryover data would satisfy 1983 model year testing requirements, EPA may
allow its use. In the event carryover of exhaust emission durability data is
granted, the exhaust emission deterioration factor will be used to determine
if emission-data vehicles, proposed running changes, or model additions meet
the exhaust emission standards.
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VI. Criteria for Carryover of Evaporative Emission Data
For evaporative durability data, the manufacturer is responsible for
determining the applicability of carryover of the evaporative deterioration
factor. For evaporative emission data, an initial determination as to the
acceptability of the proposed carryover data will be based in part on
considerations including the similarity of test -results between the
manufacturer's and EPA's facilities or special problems encountered during the
1982 certification program. The ultimate determination will be made as
follows:
A. The 1983 certification test vehicle(s) will be designated just as if
carryover had not been requested.
B. The evaporative emission control system of the test vehicle(s)
selected for 1983 will be compared with the respective 1982 system.
C. Carryover evaporative emission data will be accepted if the 1982
emission-data vehicle was tested for evaporative emissions, and;
1. Qualified to be grouped in the same evaporative emission
family as the emission-data vehicle designated for 1983,
2. Was equipped with the same exhaust, evaporative-*, and
crankcase emission control systems as the emission-data vehicle designated for
1983,
3. Differed from the emission-data vehicle selected for 1983 only
in ways (e.g., calibration differences) which, in EPA's technical judgment,
would cause the 1983 vehicle to have equivalent or superior emission
characteristics, and
4. Had emission test results which would comply with the 1983
standards after the deterioration factors have been applied.
VII. Criteria for Use of Certification Carry-Across Data
A. The criteria for determining if two (or more) vehicles are
sufficiently similar to permit the carry-across (applying data to vehicles
from more than one family or system within the same model year) of
certification data, for either exhaust or evaporative emissions, are that the
data shall meet the appropriate criteria used to judge the acceptability of
data for carryover purposes.
B. Two situations exist for which the use of carry-across data is
feasible:
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1. Light-duty vehicles and trucks; Although the standards for
gasoline-fueled and diesel light-duty vehicles differ from the standards of
the corresponding types of light-duty trucks, some manufacturers have elected
to employ the same emission control techniques on passenger cars and
light-duty trucks. Because the emission test procedures for gasoline-fueled
light-duty vehicles are the same as those for light-duty trucks (except for
the horsepower calculations), as are the emission test procedures for diesel
light-duty vehicles and light-duty trucks, the data generated from a
gasoline-fueled LDV (or LDT) may be used to satisfy data requirements for a
LDT (or LDV), provided the appropriate carryover criteria provided in this A/C
are met.
2. Evaporative emission testing within an evaporative emission
family; The evaporative emission regulations for LDV's and LDT's (41 FR
35626) established the evaporative emission family concept. This concept is
intended to require evaporative emission testing of only those test vehicles
which represent unique evaporative emission control systems. Carry-across of
data will be approved if, under the provision of A/C No. 59, the individual
evaporative emission families were eligible to be grouped together as a single
evaporative emission family and if the minimum data requirements of the
combined family are represented, in whole or in part, by the data for which
carry-across is requested. Since LDV and LDT evaporative emission families
must be separate, if two emission families differ only in that one is for
LDV's and one is for LDT's, carry-across of data will be acceptable.
Additional data requirements of the combined family, of course, would also
have to be met before certification can be granted.
VIII. Requesting the Use of Carryover and Carry-Across Certification Data
If a manufacturer intends to use carryover or carry-across data to
satisfy the 1983 model year certification requirements, EPA should be notified
in the cover letter accompanying the 1983 application for certification.
Then, the manufacturer must provide the test data which the manufacturer
proposes to use and a complete list of differences between the vehicle(s)
specified for 1983 and the vehicle(s) which generated the data for which
carryover is being requested. In addition, the manufacturer should include a
complete description of the vehicles (whether durability-data, emission-data,
fuel economy, or running change vehicles) which generated the data as a.
supplement to the application (relevant pages from the 1982 application are
usually acceptable for this purpose) or should refer to the appropriate pages
in the 1982 application.
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IX. Other Demonstration of Certification Carryover or Carry-Across
Applicability
If a 1982 vehicle does not qualify for carryover or carry-across under
Sections V, VI, VII, and VIII outlined above, but the vehicle difference(s)
would indicate that the 1983 model year vehicle will have equivalent or
superior performance, data from the 1982 model year vehicle may still be
acceptable upon demonstration by the manufacturer of the equivalence or
superiority of the proposed configuration through use of emission data or
other information to be evaluated on an individual basis*
The following list of examples is provided to facilitate the efficient
use of this option regarding the carryover or carry-across of durability
data. The list contains examples of vehicle differences which have either
been previously approved by EPA or which, in EPA's opinion, are likely to
result in equivalent or superior emissions durability. The list is not
intended to limit the use of this option. EPA will continue to evaluate
requests for vehicle differences not listed below on an individual basis. In
order for the manufacturer to approve durability carryover under the
Abbreviated Certification Review Program protocols for one or more of the
changes listed below, all of the other engine family or emission control
system parameters listed in 40 CFR 86.082-24(a)(2) or Advisory Circular No.
20-B must be the same. The manufacturer is allowed to approve durability
carryover if one or a combination of the vehicle differences listed below
exist.
Regarding manufacturer approval of carryover based on equivalence or
superiority for items listed below, the basic philosophy is that if a
particular system has been certified its physical durability and emissions
stability have been sufficiently demonstrated for purposes of preproduction
certification. If, in addition, catalyst thermal degradation is not
significantly increased, EPA believes durability carryover can be approved
without significant risk to emissions performance. Catalyst temperature,
while not the sole indicator of emissions performance, is in EPA's opinion a
significant indicator. Since catalyst temperatures provide objective criteria
for assuring that thermal degradation of the catalyst does not increase, the
manufacturers can be allowed to approve carryover. For new or unproven
systems, however, EPA has no assurance that carryover can be approved without
significant risk to emissions performance. Therefore, manufacturers must
continue to submit to EPA requests for carryover of data to new systems or to
systems that EPA has not determined are likely to result in equivalent or
superior performance as outlined below.
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In certain instances, EPA expects that manufacturers will want to
carryover data to a vehicle using systems or components that are not identical
to ones that have been used in a family that has been previously certified.
In those cases where a particular system or component differs by more than
calibrations from one that has been used previously, it is the manufacturers'
responsibility to assure that whatever minor differences exist will not
adversely affect emissions deterioration. If the manufacturer does not have
an adequate basis and associated documentation for such a determination,
carryover should not be approved. EPA intends to exercise its option to audit
and review data or other information utilized in making such determinations.
This audit process will be facilitated if the manufacturer prepares a list of
all differences (other than calibrations) between the system or component
intended for production and the one that was previously used in a certified
family and addresses the durability impact of each difference. In addition,
EPA may confirm the validity of the manufacturers' determinations through its
in-use vehicle testing programs which could result in recall and denial of
future carryover of particular data.
A. Engine Displacement
Carryover of durability data from a larger displacement engine to
one that is more than 50 cubic inches or 15 percent smaller may be approved by
the manufacturer if:
1. the engines are otherwise qualified to be in the same engine
family in terms of the engine parameters specified in 40 CFR
86.082-24(a)(3), and
2. catalyst thermal degradation does not increase significantly^
due to this change.
If the block configuration, valve locations, or cylinder bore
center-to-center dimensions are not the same, the manufacturer must submit a
request for carryover with specific information, catalyst temperature data,
and any evidence of engine out emissions stability (may include bench test
data, etc.) to EPA for evaluation.
B. Fuel System
Case 1. The number of carburetors, number of Venturis, or principle
of carburetor operation (e.g., simple venturi, air valve, constant depression)
may be deemed equivalent for durability purposes and the manufacturer may
approve durability carryover ifJ
1. the carburetor model intended for production has been used in a
family that has been previously certified^ by that manufactuer
and
2. catalyst thermal degradation does not increase significantly^
due to this change.
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Case 2. Carryover of durability data from a vehicle using one or
more carburetors to a vehicle using any electronic timed or pulsed fuel
injection system may be approved by the manufacturer if*
1. the fuel injection system design intended for production has
been used in a family that has been previously certified5 by
that manufacturer and
2. catalyst thermal degradation does not increase significantly due
to this change.^
Case 3. Carryover of durability data from a vehicle using throttle
body fuel injection to a vehicle using electronic timed or pulsed multipoint
intake manifold fuel injection may be approved by the manufacturer ifi
1. the fuel injection system design intended for production has
been used in a family that has been previously certified5 by
that manufacturer and
2. catalyst thermal degradation does not increase significantly due
to this change.^
For any other fuel system changes that could not normally be grouped
in the same engine family, the manufacturer must submit a request for
carryover with specific information, catalyst temperature data, and any
evidence of physical durability or engine out emissions stability (may include
bench test data, etc.) to EPA for evaluation.
C. Catalyst
Case 1. The manufacturer may approve the carryover of durability
data for any of the following differences;
1. change in general catalyst location away from engine (downstream
movement, e.g., from engine compartment to underfloor area).
2. increase in catalyst volume (in excess of 15 percent of largest
volume) at the same or higher noble metal loading (g/ft3 and
proportion of active constituents).
3. increase in active material loading of any or all noble metals
(proportion of active constituents may only be changed by
increasing the load of particular noble metals—decreases in
active material loadings must be evaluated under the
"essentially equivalent" provisions of A/C No. 20B).
Case 2. Carryover of durability data to a vehicle using different
basic catalyst packaging (e.g., materials, technique of containment and
restraint, and general method of construction) or substrate construction
technique («.g., extruded, laid-up, formed) may be approved by the manfacturer
ifi
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1. the basic catalyst packaging or substrate construction technique
intended for production has been used in a family that has been
previously certified5 by that manufacturer and
2. catalyst thermal degradation does not increase significantly due
to this change.^
For any other catalyst changes that could not be grouped in the same
engine family and emission control system under A/C 20B, the manufacturer must
submit a request for carryover with the specific information, catalyst
temperature data, and evidence of physical durability and emissions stability
to EPA for evaluation.
D. Air Injection
Case 1. Carryover of durability data to a vehicle which differs in
general location of injected air, general method of driving air pump, or
modulation of secondary air flow rate may be approved by the manufacturer if;
1. the basic air injection system intended for production,
including general location of injected air, general method of
driving air pump, or modulation of secondary air flow rate, as
applicable, has been used in a family that has been previously
certified5 by that manufacturer and
2. catalyst thermal degradation does not increase significantly due
to this change.^
Case 2. Pump air injection and pulse air injection may be deemed
equivalent for durability purposes and durability carryover may be approved by
the manufacturer if:
1. the basic air injection system intended for production,
including general location of injected air, general method of
driving air pump, or modulation of secondary air flow rate, as
applicable, has been used in a family that has been previously
certified5 by that manufacturer and
2. catalyst thermal degradation does not increase significantly due
to this change.^
Case 3. Carryover of durability data from a vehicle with no air
injection to a vehicle with either pump air injection or pulse air injection
may be approved by the manufacturer if4
1. the basic air injection system intended for production,
including general location of injected air, general method of
driving air pump, or modulation of secondary air flow rate, as
applicable, has been used in a family that has been previously
certified5 by that manufacturer and
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2. catalyst thermal degradation does not increase significantly due
to this change.^
For any other air injection changes that could not be grouped in the
same control system under A/C No. 20B, the manufacturer must submit a request
for carryover with specific information, catalyst temperature data, and any
evidence of physical durability or emissions stability (may include bench test
data, etc.) to EPA for evaluation.
E. Exhaust Gas Recirculation
Carryover of durability data to a vehicle which differs in general
location of exhaust gas pickup, general point of exhaust gas introduction, or
general method of modulating quantity of EGR may be approved by the
manufacturer if;
1. catalyst thermal degradation does not increase significantly due
to this change^ and
2. the basic EGR system Intended for production, including general
pickup location, general introduction point, and general
modulation method, has been used in a family that has been
previously certified^ by that manufacturer. (EPA has noted
that other items such as EGR valve location and pintle design,
EGR flow passageway design, cooling method design, transducer
designs, diaphram materials, etc., can also affect EGR system
deterioration. The manufacturer should document that any
changes to these items do not cause increased EGR system
deterioration.)
For any other EGR changes that could not be grouped in the same
control system under A/C No. 20B, the manufacturer must submit a request with
specific information, catalyst temperature data, and evidence of physical
durability and emissions stability (may include bench test data) to EPA for
evaluation.
F. Electronic Control Systems
While Electronic Control Systems are not listed among the engine
family or emission control system determinants in A/C No. 20B, EPA has noted
that certain aspects of these systems can affect emissions durability and
offers the following as a guideline for assuring that the 1982 durability-data
vehicle was generally representative of the 1983 durability-data vehicle.
Different electronic control systems may be deemed equivalent for durability
purposes and the manufacturer may approve durability carryover under the
following conditions:
1. The sensor and controller designs intended for production have
been used in a family that has been previously certified5 by
that manufacturer.
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2. The use of a malfunction warning system may not be deleted.
3. The following parameters may not be deleted;
a. Electronic Spark Control
b. Sensing of EGR Valve Position or Flowrate
4. The following parameters may not be added or deleted:
a. Sensing of Exhaust Gas Oxygen or Content
b. Sensing of Mileage (or inferred mileage in the form of Time)
c. EGR Control
d. Feedback Fuel Control
Requests for carryover that do not meet the above conditions may be
submitted to EPA for evaluation. The request should include specific
information and evidence of physical durability and emissions stability (may
include bench test data, etc.)
X. General Criteria for Carryover of Fuel Economy Data From Vehicles for
Which Certification Carryover is Requested
A. When requesting approval to use emission data generated by vehicles
selected in accordance with the provisions of 40 CFR Part 86 for carryover
certification, the manufacturer should be cognizant of the fact that the EPA
approved fuel economy values must also be considered as part of the request.
These fue] economy data, or the fuel economy data generated in accordance with
the criteria set forth in paragraph X.F, will be used in the fuel economy data
base.
B. The general criteria which EPA will use to determine the
appropriateness of any carryover request are outlined in Section IV. For fuel
economy carryover purposes, any certification vehicle for which emission
carryover is requested and which satisfies the criteria in Section V of this
A/C also satisfies the provisions of 40 CFR 600.007-80(a) for vehicle
acceptability.
C. A carryover request which does not satisfy the general criteria set
forth in Section V of this A/C will not be considered for either emission-data
carryover or fuel economy carryover and, therefore, a new emission-data
vehicle will be required.
D. Once the vehicle acceptability has been determined, the 1982 data
will be evaluated as to representativeness for 1983 by determining if (as a
minimum):
1. The 1982 vehicle was tested at the same or higher equivalent
test weight,
2. The 1982 vehicle was tested at the same or higher road load,
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3. The 1982 vehicle was shifted in a manner consistent with the
shift procedure guidelines set forth in A/C No. 72 or at speeds which would be
expected to understate the fuel economy performance,
4. The 1982 vehicle differed from the 1983 emission-data vehicle
selected only in ways which, in EPA's technical judgment, would cause the 1983
vehicle to have equivalent or superior fuel economy characteristics.
E. For those certification and fuel economy data judged by EPA to be
representative, the fuel economy data generated by the certification vehicle
will be used, that is, carryover of data (both fuel economy and certification)
will be approved. In fact, data from a certification vehicle which satisfy
the criteria for acceptability and representativeness must be used in the fuel
economy program.
F. In those cases where the certification data satisfy the criteria of
Section V, but the fuel economy are judged by EPA to be unrepresentative
because they would be expected to overstate the 1983 fuel economy values, or
there is a degree of uncertainty regarding the evaluation of
representativeness in paragraph X.D above, the manufacturer will be required
to test a 1983 fuel economy data vehicle (FEDV). If any of the emission
levels from the FEDV exceed the emission standards with the appropriate
deterioration factor applied, then the data from the FEDV are unacceptable and
the request for carryover of 1982 emission data will be denied. If the data
meets the standards and the requirements of 40 CFR 600.007-80 then, because
the FEDV is a 1983 vehicle tested in accordance with the 1983 test procedures,
the FEDV will satisfy the criteria of acceptability and representativeness.
However, the data must still satisfy a fuel economy reasonableness check.
G. If the fuel economy data from the 1983 FEDV are judged to be
reasonable, the data will be used. Also, if the data from the 1983 FEDV
confirm the fuel economy data from the 1982 emission-data vehicle, both sets
of fuel economy data will be used. In both cases, the emission results from
the 1982 emission-data vehicle will be used. That is, the carryover request
(both fuel economy and emission-data) will be approved.
H. If the fuel economy data generated by the 1983 FEDV at the
manufacturer's facility are judged to be unreasonable, the vehicle will be
subjected to EPA confirmatory testin? If the emission data, generated at EPA
in accordance with the provisions of J CFR 86.081-29, do not meet the
emission standards with the appropriate deterioration factor applied,
carryover will be denied and a new emission-data vehicle will be required. If
the emission data from the 1983 FEDV meets the emission standards, the 1983
emission-data carryover request will be granted. However, the fuel economy
data must still satisfy the reasonableness criteria.
I. Once the fuel economy data generated at EPA satisfy the
reasonableness check, the fuel economy data from the 1983 FEDV will be used to
satisfy the 1983 fuel economy carryover request and emission data carryover
will be granted, as described in paragraph X.G.
-------
U.S. Environmental OANR/MS A/C NO. I?F
Protection Agency PAGE is OF 1?
XI. General Criteria for Carryover of Fuel Economy Data from Vehicles Other
Than Those for Which Certification Carryover is Requested'
A. A request for carryover of fuel economy data from vehicles other
than those for which certification carryover is requested must be submitted
with an FEDV package indicating that the data are from a prior model year.
B. Vehicles other than those for which certification carryover is
requested must satisfy the criteria set forth in Section V of this A/C to be
considered for fuel economy carryover.
C. Since the vehicles which generated these data have previously
satisfied the vehicle acceptability and data reasonableness criteria, the data
need only satisfy the representativeness criteria (paragraph X.D of this A/C).
D. Data which satisfy all of the criteria will be included in the fuel
economy data base in accordance with the provisions of 40 CFR 600.008-77(b).
E. Any vehicle which does not satisfy the certification carryover
criteria and/or data which do not satisfy the representativeness criteria will
cause the carryover request to be denied.
Director, Office of Mobile Sources
Attachment
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U.S. Environmental OANR/MS A/C NO. 17F
Protection Agency PAGE 16 OF 17
ENDNOTES
1. "Qualified to be grouped in the same engine family" means that the
current year vehicle and the vehicle which generated the proposed
carryover data must be identical in all the aspects listed in A/C No.
20B, Sections D, E, F (four-stroke, two-stroke, or rotary engines
respectively).
2. "Qualified to be grouped in the same evaporative emission family" means
that the current year vehicle and the vehicle which generated the
proposed carryover data must be identical in all the aspects listed in
A/C No. 59, Section D.
3. The same basic evaporative emission control system as specified in A/C
No. 59, Section E.
4. It is the manufacturer's responsibility to assure that an increase in
catalyst temperature will not result in increased thermal degradation of
the catalyst. If the manufacturer has any reason to suspect that thermal
degradation of the catalyst will increase significantly, carryover may
not be approved. EPA believes that thermal degradation of the catalyst
is not likely to increase if catalyst temperatures do not increase. EPA
intends to look more closely at those cases where catalyst temperatures
increase significantly. Criteria are offered below as a guideline to
determine If catalyst temperatures are significantly affected. These
criteria allow small increases in time and temperature to account for
measurement variability. A manufacturer may determine that other
criteria are more appropriate for establishing the acceptability of
carryover for its designs* The manufacturer should document the basis
for Its determination that thermal degradation of the catalyst will not
increase significantly. If a manufacturer believes that the following
guideline is not appropriate for a particular situation and can document
that thermal degradation of the catalyst will not increase even though
these criteria are not met, durability carryover may still be approved.
However, when the following criteria are not met, the manufacturer should
notify EPA in writing at the time the carryover decision is made. This
will allow most timely EPA audit of the manufacturer's carryover
decision. The amount of time spent in the following temperature
intervals is not increased by more than three percent or 60 seconds,
whichever is greater, during the mileage accumulation cycle
(approximately 2 hour cycle) unless there is a corresponding decrease in
time at a higher temperature interval. The temperature intervals are
601°C to 650°C, 651°C to 700°C, 701°C to 750°C, and 751°C to 800°C (other
intervals within this range may be appropriate, the 60 second tolerance
applies to a 50°C interval). If maximum temperatures are above 800°C,
the maximum temperature is not increased by more than 2 percent and
amount of time above 800°C is not increased by more than two percent or
30 seconds, whichever is greater. Whenever possible, the impact of a
-------
U.S. Environmental OANR/MS A/C NO. i7F
Protection Agency PAGE 1? OF 1?
change on catalyst temperatures should be evaluated on a single vehicle,
preferably the original durability-data vehicle. If the original
durability-data vehicle is not available, the highest selling
configuration from either of the model years is preferred. If it is not
practical to evaluate the change on a single vehicle, other vehicle
differences which could affect catalyst temperatures should be
minimized. Again, configurations representing highest sales from each
model year should be used if practical. Thermocouples should be located
to provide accurate measurement of maximum temperatures. Each
manufacturer should obtain a description of such location from his
catalyst supplier and retain this with the rest of the documentation. If
this is not possible, thermocouples may be located within the catalyst
container at the approximate mid-point of the exhaust stream and
approximately one inch from the substrate.
5. Carryover may not be approved for any components or systems that were
used in families certified without completing the 50,000-mile
certification provout under the small volume provisions of 40 CFR
86.082-24(e). Manufacturers must continue to submit requests to EPA for
carryover involving systems or components that have not completed the
50,000 mile certification proveout. Requests for carryover may also be
submitted to EPA if the 50,000-mile certification proveout has been
successfully completed but a certificate was never obtained.
-------
Attachment
CARRYOVER CRITERIA FLOW CHART FOR 40 CFR PART 86 VEHICLES
NO
7
NO CERT.
UR F.E.
c/o
(1) c/o - carryover
(2) EUV - emission-data
vehicles
(3) FE - fuel economy
(4) FEDV - fuel economy
data vehicles
NOTE 1:
USE 1983 FE DATA AND
1982 CERT. DATA FOR C/O.
USE 1902 FE DATA PRO-
VIDED 1983 FEDV DATA
CONFIRMS 1982 DATA IS
REASONABLE.
-------
UPDATE
Attached are revised pages to replace the endnotes of Advisory
Circular No. 17F. Please discard pages 16 and 17 of the
endnotes issued November 16, 1982 and insert the revised pages
dated January 21, 1988. Explanation of the revisions is
provided in manufacturer guidance letter CD-88-02, dated
January 21, 1988.
-------
U.S. Environmental OANR/MS A/C NO. I?F
Protection Agency PAGE_IL_ OF.H
XI. General Criteria for Carryover of Fuel Economy Data from Vehicles Other
Than Those for Which Certification Carryover is Requested
A. A request for carryover of fuel economy data from vehicles other
than those for which certification carryover is requested must be submitted
with an FEDV package indicating that the data are from a prior model year.
B. Vehicles other than those for which certification carryover is
requested must satisfy the criteria set forth in Section V of this A/C to be
considered for fuel economy carryover.
C. Since the vehicles which generated these data have previously
satisfied the vehicle acceptability and data reasonableness criteria, the data
need only satisfy the representativeness criteria (paragraph X.D of this A/C).
D. Data which satisfy all of the criteria will be included in the fuel
economy data base in accordance with the provisions of 40 CFR 600.008-77(b).
E. Any vehicle which does not satisfy the certification carryover
criteria and/or data which do not satisfy the representativeness criteria will
cause the carryover request to be denied.
arson
Director, Office of Mobile Sources
Attachment
-------
U.S. Environmental OAR/OMS A/C NO..
Protection Agency
ENDNOTES TO ADVISORY CIRCULAR NO. 17F
1. "Qualified to be' grouped in the same engine family" means that the
current year vehicle and the vehicle which generated the proposed
carryover' data must be identical in all the aspects listed in A/C
No. 20B, Sections D, E, F (four-stroke, two-stroke, or rotary engines
respectively).
2. "Qualified to be grouped in the same evaporative emission family", means
that the current year vehicle and the vehicle which generated the
proposed carryover data must be identical in'all the aspects-listed in
A/C No. 59, Section D.
3. The same basic evaporative emission control system as specified in A/C
No. 59, Section E.
4. It is the manufacturer's responsibility to assure that an increase in
catalyst temperature will not result in increased thermal degradation of
the catalyst. If the manufacturer'has any reason to-suspect1 that thermal
degradation of the catalyst will increase significantly, carryover - may
not be approved. EPA believes that thermal degradation of the catalyst
is not likely to increase if'catalyst temperatures do not increase. EPA
intends to look more closely at those cases where catalyst temperatures
increase significantly. Criteria are of-fered below as a guideline to
determine if catalyst temperatures are significantly affected. These
criteria allow small increases in time and temperature to account for
measurement variability. A manufacturer may determine that other
criteria are more appropriate for establishing the acceptability of
carryover for its designs. The manufacturer should document the basis
for its determination that thermal degradation of the catalyst will not
increase significantly. If a manufacturer believes that the following
guideline is not appropriate for a particular situation and can document
that thermal degradation of the catalyst will not increase even though
these criteria are not met, durability carryover may still be approved.
However, when the following criteria are not met, the manufacturer should
notify EPA in writing at the time the carryover decision is made. This
will allow most timely EPA audit of the manufacturer's carryover
decision. The amount of time spent in the following temperature
intervals is not increased by more than 3 percent or 60 seconds,
whichever is greater, during the mileage accumulation cycle (approxi-
mately 2 hour cycle) unless there is a corresponding decrease in time at
a higher temperature interval. The temperature intervals higher tempera-
ture interval. The temperature intervals are 601°C to 650°C, 651°C to
700°C, 701°C to 750°C, and 751°C to 800°C (other intervals within this
Revised: 1-21-88
-------
U.S. Environmental OAR/OMS A/C NO. 17F
Protection Agency PAGE_1Z_ OFJL
range may be appropriate, the 60 second tolerance applies to a 50°C
interval). If maximum temperatures are above 800°C, the maximum tempera-
ture is not increased by more than 2 percent and amount of time above
800°C is not increased by more than 2 percent or 30 seconds, whichever is
greater. If the catalyst uses AlzOj for support but does not contain
Hi, only increases in time at temperatures above 700°C need to be
considered. For oxidation catalysts which use AlzOs for support but
do not use Ni and do not use Rh, only increases in time at temperatures
above 750°C need to be considered.
Whenever possible, the impact of a change on catalyst temperatures
should be evaluated on a single vehicle, preferably the original
durability-data vehicle. If the original durability-data vehicle is not
available, the highest selling configuration from either of the model
years is preferred. If it is not practical to evaluate the change on a
single vehicle, other vehicle differences which could affect catalyst
temperatures should be minimized. Again, configurations representing
highest sales from each model year should be used if practical.
Thermocouples should be located to provide accurate measurement of
maximum temperatures. Each manufacturer should obtain a description of
such location from his catalyst supplier and retain this with the rest
of the documentation. If this is not possible, for monolith catalysts.
thermocouples may be located within the catalyst substrate at the
approximate radial center of the exhaust stream and approximately one
inch downstream from the front face of the substrate. If the catalyst
is composed of multiple containers or multiple substrate biscuits in the
same container, more than one thermocouple is required. Locate one
thermocouple within each substrate biscuit as described above. Thermo-
couples should not be located in the exhaust pipe, in free exhaust air,
or directly in the delivery path of secondary air injection systems.
5. Carryover may not be approved for any components or systems that were
used in families certified without completing the 50,000-mile certifica-
tion proveout under the small-volume provisions of 40 CFR 86.082-24(e).
Manufacturers must continue to submit requests to EPA for carryover
involving systems or components that have not completed the 50,000-mile
certification proveout. Requests for carryover may also be submitted to
EPA if the 50,000-mile certification proveout has been successfully
completed but a certificate was never obtained.
Revised: 1-21-88
-------
Attachment
CARRYOVER CRITERIA FLOW CHART FOR 40 CFR PART 86 VEHICLES
NO
^
NO CEKT.
UR F.E.
c/o
ARE FE DATA
REPRESENTATIVE
(1) c/o - carryover
(2) EUV - emission-data
vehicles
(3) FE - fuel economy
(4) FEDV - fuel economy
data vehicles
MOTE 1.
USE 1983 FE DATA AND
1982 CERT. DATA FOR c/o.
USE 1982 FE DATA PRO-
VIDED 1983 FEDV DATA
CONFIRMS 1982 DATA IS
REASONABLE.
SEE
MOTE
1
MEETS "X.NO
EMISSION STAND-
ARDS
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