United States
Environmental Protection
Agency
Office of Air and Radiation
(ANR-443)
Washington, DC 20460
OOOR9010
Air
Recommended I/M Short Test
Procedures For the 1990fs:
Six Alternatives
Technical Report
U.S. Environmental Protection Agency
Region 5, Library (PL-12J)
77 West Jackson Boulevard, 12th Floor
Chicago, IL 60604-3590
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Table of Contents
Page
1.0 INTRODUCTION
2.0 PRECONDITIONED IDLE TEST PROCEDURE 7
2.1 General Requirements 7
2.2 Initial Test 7
2.3 Second-Chance Test 8
2.4 Tampering and Safety Testing 9
2.5 Graphic Illustration of Preconditioned Idle Test 10
3.0 IDLE TEST PROCEDURE 13
3.1 General Requirements 13
3.2 Initial Test 13
3.3 Second-Chance Test 14
3.4 Tampering and Safety Testing 15
3.5 Graphic Illustration of the Idle Test 15
4.0 IDLE TEST PROCEDURE WITH LOADED PRECONDITIONING 18
4.1 General Requirements 18
4.2 Initial Test 18
4.3 Second-Chance Test 19
4.4 Tampering and Safety Testing 20
4.5 Graphic Illustration of Idle Test with
Loaded Preconditioning 20
5.0 PRECONDITIONED TWO SPEED IDLE TEST PROCEDURE 23
5.1 General Requirements 23
5.2 Initial Test 23
5.3 Second-Chance Test 25
5.4 Tampering and Safety Testing 27
5.5 Graphic Illustration of Preconditioned
Two Speed Idle Test 28
6.0 TWO SPEED IDLE TEST PROCEDURE 32
6.1 General Requirements 32
6.2 Initial Test 32
6.3 Second-Chance Test 34
6.4 Tampering and Safety Testing 35
6.5 Graphic Illustration of Two Speed Idle Test 35
7.0 LOADED TEST PROCEDURE 38
7.1 General Requirements 38
7.2 Loaded Mode 38
7.3 Idle Mode 39
7.4 Tampering and Safety Testing 39
7.5 Graphic Illustration of the Loaded Test 40
8.0 GRAPHIC ILLUSTRATION OF TEST PROCEDURES 43
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1.0 INTRODUCTION
Status of This Document - The test procedures presented in
this report represent the best technical information EPA has on
how to test current technology vehicles, and do not represent a
new requirement at this time. EPA recognizes that for I/M
programs to adopt these new procedures, changes in regulations,
rewriting test protocols, software and, in some cases, hardware
upgrades, and other changes would be needed and would require time
to implement. This report is being released at this time so that
programs may take advantage of any opportunities that arise to
update the test procedures as they make other program changes,
including changes necessary to comply with requirements of the
1990 amendments to the Clean Air Act. EPA is in the process of
revisiting the emission performance warranty regulations (40 CFR
85 Subpart W) , and intends to incorporate these procedures into
the revised regulations. EPA has not yet considered whether
states and localities should be required to eventually adopt and
implement a test from among those described here. While notice
and opportunity for comment would be provided for any such
proposal, EPA welcomes informal comment at any time.
Problems with Current Tests - Short emission tests are used
in I/M programs to predict whether a vehicle would achieve
effective emission reductions from a repair. In the process of
doing so, there is a possibility for errors of commission (false
failures) or errors of omission (false passes) to occur. The
advent of new technology vehicles with sophisticated computer
controls appears to have led to a situation where test variability
is more pronounced and test errors may pose a serious cost and
inconvenience to the public. Several sources of information
suggest that as many as one-third of the failures of 1981 and
later vehicles in some I/M programs may be useless in terms of air
quality benefit. In large part, this problem has been found to be
the result of specific test conditions, such as excessive idling,
inadequate preconditioning or improper warm-up. The problem is
found in both centralized and decentralized programs.
In response to this, EPA has been evaluating various
alternative test approaches in an attempt to reduce test errors
and to address many of the known problematic operating conditions.
Several studies were conducted in which vehicles were tested using
a variety of operating conditions to assess the effects of various
types of preconditioning. In some cases, data were collected on a
second-by-second basis to better characterize the behavior of the
vehicle during the test procedure. The results of these studies
are detailed in other reports, either already issued or soon to be
completed (see EPA 460/3-88-008, Variability of I/M Test Scores
Over Time and EPA-AA-TSS-I/M-87-2, I/M Test Variability) . The
findings from these studies serve as the basis for the test
procedures that follow.
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New procedures have been developed for all current tests.
Though these procedures have been developed to address problems
most frequently found in new technology vehicles, they are
intended for use on vehicles of all model years . The new
procedures differ in a number of ways from existing tests: mode
lengths are variable, second chance tests are automatically done
on failed vehicles in all tests except the loaded test, controlled
preconditioning is required, and test results are chosen in a more
sophisticated manner.
Alternative Procedures - Six new procedures are presented.
There are three variations of the idle test: the preconditioned
id 1 e _ testj__vi th. _hlgh .speed , neutr a; 1_ (2500 rpm) " p_r e c o n d i t i o ivJng_'
prior to jthe _idle mode_; the idle test, with high speed neutral
on the jsecond chance~fest ; a n d^YHeTTd eT/tei 3 1
~ "
____
wj.th. leaded ____ P£e ccj^J^i onjLnc^ ___ a.23.i~n "with -^ Pre"condi t ionTng
performed J3nly__on_the_ s_ecg_nd^_cjian_ce.. testTT Two va rT a tfio n s~" "of "" tTfe
Two speed idle test are presented. In the preconditioned two
speed idle test, the high speed mode precedes the idle mode and
serves as both a testing mode and a preconditioning mode for the
subsequent idle mode. In the two speed idle test the order of the
high speed and idle modes is reversed, which may, in certain
circumstances, enable the test to be performed more quickly.
A loaded test procedure is also presented. The re-ader will
note that a second-chance test is not required in this procedure.
EPA believes that loaded testing and preconditioning gives an
accurate enough picture of a vehicle's true operating condition
that second-chance tasting is not necessary. However, states may
still incorporate itijthey so desire.
Test Length - Each initial test sequence (with the exception
of the idle test and idle test with loaded preconditioning)
consists of two modes. Both a preconditioning mode or high speed
testing mode, and an idle testing mode are used. The minimum test
mode length is thirty seconds in all cases. The maximum mode
length varies depending upon the type of mode and whether it is
part of an initial or second-chance test. The maximum mode length
is ninety seconds in most cases. This flexibility in mode length
is designed to allow vehicles ample time to reach stable emission
levels, become sufficiently warmed up, purge vapors in the
evaporative canister and the like. The maximum test time is set
at 180 seconds if a test mode and second-chance preconditioning
mode are combined (see below) . we anticipate that most vehicles
will complete the test at, or soon after, the minimum test time.
Second Chance to Pass - Second chance te_sts ^shojjld^ be
,£OJ2^i£t^dj3n__aJJ^_^^ shows that
th_is j3ignjL£icantlv reduc_e_s_ errors^ o£~~commis!3Lon7~ At f~Irst glance,
the second chance test may ' seem ~ like ~a burdensome imposition,
especially for centralized programs. It must be realized,
however, that doing a second chance test will mean fewer vehicles
having to be retested at a later date, with the result that total
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testing volume is decreased. Second-chance testing may therefore
result in a net cost savings and a net time savings to the
program. Of course, it will also mean that owners of cLean
vehicles__wil_l pe lesj__lijcely to suffer the cost., and"' inconyenj.ence'
~ repailf and__a_-retes't ~t'ri'p_._ The second chance
_ usually only in the length of
_^
p rec o n djoalngT TTTe research resTEs Thdicate that 180 seconds
'of high speed neutral preconditioning will adequately address most
evaporative canister purge problems, exc_£S_sJ.ve_J.xi^inc[_ efjrects, and
coldt.ejnp_era^u£e"^sT:fng7^oblems . While some concern has been
expressed that vehicles might overheat if kept in a high speed
neutral mode for this period of time, it should be pointed out
that raising engine speed increases the circulation of engine
coolant, hence engine overheating should not occur as a result of
testing a vehicle in this mode. Loaded preconditioning will
accomplish the same results in considerably less time. Thirty
seconds is sufficient when the loaded mode is only for
preconditioning. Whjin__a_j£eJii£^j:ejigi^^ ttie
secpnd-chancetest scores__supersede the scoreT'of the initial
test" " ' " ' ~
Preconditioned and standard versions of the two speed and
idle tests are described in this report. The preconditioned
version of a given test preconditions all vehicles briefly before
the first testing mode to help reduce the number of vehicles that
fail, and requires more extended preconditioning prior to the
second chance testing mode. The standard version saves time up
front by not preconditioning at all before the first testing mode,
but may result in more vehicles needing the second chance test .
T h e c h o i.c e __oJ;L whe ther a preconditioned^ or standard test is
most appropriate for any given program" will depend on operating
2£ndTt_i_ons in~~"tha£j3roc[ram. The standard versions are intended to
minimize tKeTesting time "for the majority of clean vehicles which
may maximize overall throughput. This approach has been very
successful in the three centralized programs that are using loaded
preconditioning. It is not clear, however, that this is the best
approach for all centralized programs. In situations where wait
times are brief, the standard approach should be a good choice.
In those centralized programs where wait times are a problem, or
in decentralized programs where vehicles are left at the station
and soak for a period of time prior to being tested,
preconditioning all vehicles for a short time (30 seconds) may be
more efficient than the standard approach. EPA is unsure at this
point about the trade-off between doing preconditioning prior to
the initial idle test for a short time, versus skipping this and
preconditioning only on the second chance test . EPA would
jsncoujrage programs, especially centralized programs, to '
"
wit hj_±Ji£ai_J[Tt e r n at i . ve_a pp"ro a^che_s__aiid_ Jc eg_p__Tra_c k_ o jjtoTaT fes~t
times, the number of~~ vehicles that switch results between Initial
"arid second-chance tests, and the like to see ji_f one method is
superior. ~~
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Test Times and Mode Times Within a Test - Two software timers
are required in order to run any of these test sequences. The
test timer begins when the inspector prompts the analyzer to begin
testing. Once started, this timer runs continuously until the
test sequence is completed or until the overall maximum test time
is reached. The test timer resets at the start of second-chance
preconditioning. The mode timer governs the individual modes of
the test and begins once specified conditions are met (generally,
CO+C02 minimums are reached and RPM levels are within allowable
bounds). The mode timer may automatically reset to zero if engine
speed limits are violated at any point during the mode. Other
problems, such as the vehicle stalling, would cause the test to
abort altogether.
The overall maximum time limit is intended to end the test
when recurring problems with the test procedure cause excessive
delay in completing the process. The maximum time limit is based
on the following formula:
10 seconds + 1.5*first mode maximum
+ 10 seconds + 1.5*second mode maximum.
This is based on the observation that rpm excursions tend to occur
in the early part of a test mode and are less likely to occur in
the latter part. This algorithm essentially allows a vehicle to
have one rpm excursion per mode and still have the benefit of the
maximum mode time. It also allows ten seconds prior to each mode
for the vehicle to attain the specified mode conditions as well as
for full analyzer response. This approach is similar to what is
currently used in most test procedures. If the maximum overall
test time is reached before all test modes can be completed the
test will abort and the vehicle must be retested or rejected for
whatever reasons may apply (e.g., leaking exhaust).
Sampling Algorithm and Pass/Fail Determination - The test
algorithms are essentially identical for all procedures. The
typical approach now used in most I/M programs is to use the last
five seconds of the 30 second test period as the test result. The
algorithm in the following procedures would continuously monitor
emission readings. If at any time passing readings are obtained
for both HC and CO, then the vehicle passes that mode of the test.
If the minimum mode time has elapsed, the mode would end. If not,
testing of an already passed vehicle would continue until the
minimum time is reached, or until scores of 100 ppm HC and 0.5%
CO, or less are obtained. Vehicles that have not yet passed when
the minimum mode time is reached would continue sampling until
passing scores are obtained up to the maximum mode time. These
early out cutpoints are designed to reduce test times for very
clean vehicles but to still give vehicle owners and program
managers information on how clean each vehicle really is.
As just described, any vehicle that finally fails will have
been sampled for at least 180 seconds, plus the time required to
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adjust rpm levels, etc. EPA generally believes that this time
investment is worthwhile to protect passable vehicles. However,
in order to prevent delays in testing and damage to the equipment
due to HC hangup, programs might adopt a high end early out
cutpoint for very dirty vehicles, such that if a vehicle has had
no HC score lower than 1800 ppm, or 90% of full scale, when the
minimum mode time has elapsed, the mode would end, the vehicle
would fail, and no second chance test would be performed. This
feature has not been written into the test procedures, however,
and would have to be added if desired.
Score Reporting - The emission readings reported on the test
form for a mode would not necessarily be the first passing reading
obtained but rather the lowest combined HC+CO reading found during
the mode. The lowest reading better represents the performance of
the vehicle. Since the figure for the HC score is up to two
orders of magnitude higher than the figure for the CO score, the
score reporting algorithm weights the CO score using a factor of
151 before adding it to the HC score. This weighted figure is
used to choose the HC and CO pair to report. In case of second-
chance tests, the results from the second-chance modes would be
reported.
Warranty - Despite the fact that these tests are not being
formally promulgated under Section 207 of the Clean Air Act, it is
our belief that motor vehicle manufacturers will honor warranty
claims based on failure of one of these tests. Experience in two
programs in which test variations are in use show this to be the
case. Further, the Motor Vehicle Manufacturers Association of the
United States, Inc. (MVMA) has stated that its members support
these alternatives and EPA will certainly work with any vehicle
manufacturer who might have problems.
Future Directions - It will be apparent to the reader that
one premise behind these test procedures is that a vehicle with
only a transitory period of high emissions should not be failed if
it can also show a reasonably sustained period of low emissions.
All the evidence available to EPA indicates that few if any truly
dirty vehicles will be accidentally passed as a result of the
extra opportunity to pass compared to current test procedures.
However, dirty vehicles which have been escaping detection even
with the current idle test or two-speed idle test are likely to
continue to do so. It is EPA's hope that these new procedures
will improve the future possibility of using more stringent
cutpoints and non-idle test modes to detect these high emitters,
by eliminating the additional false failures which would occur if
such changes were made with the current sampling algorithms and
the absence of a second-chance test. EPA's research on I/M test
procedures is now focused on such changes.
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Implementing These Procedures - States will need to keep a
number of factors in mind in the course of incorporating one of
these test procedures into the analyzer specifications. The
numeric specifications, as detailed in the tables that follow the
test procedure descriptions, will need to be stored in such a way
that they can be reprogrammed relatively easily should future
operating experience indicate the need to do so. The analyzer
sofjtware will also need the ability to st,ore multiple sets of
emissions^ readiricfs _f rom__wKTcH^jtrh_g '"fTnliT""' scfore^irT"a ~ test is"
"sere"cired7~] and theability~ to store scores from ~ the iru±TaT~~t:"estf
'when a second-chance test is conducted. XSta^£s_JJia£__have_iadopted_
BAR 90 type equiprnen t__speci f icatiojns __wil_l__Jbe_able to adopt one "or
more'' o_f^h^se ^procedures zelatiyeT}T~~easiIy .. "Tncorp'brating these
procedores Irvto~BART 84~T:ype analyzers™ will be more difficult, and
will require careful attention to ensure that all essential
features of these tests are incorporated into the machine
software.
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2 . 0 PRECONDITIONED IDLE TEST PROCEDURE
2 . 1 General Requirements
The test sequence shall include at least the following
parameters: HC, CO, C02, and engine rpm. The analyzer shall
prompt the inspector to test the vehicle in as-received condition,
with the transmission in neutral or park, all accessories turned
off, and the engine running at normal operating temperature (based
on a temperature gauge reading or touch test on the radiator
hose, and visual observation for overheating) . The inspector
shall deploy a tachometer, insert the sample probe into the
tailpipe and the test sequence shall begin. The test timer
governing the overall test sequence shall start at the start of
sampling. A separate mode timer shall govern the modes within the
test sequence and shall start when the specified conditions are
met. The anti-dilution criterion shall be a minimum combined CO
and C02 concentration of six percent for all light duty vehicles
and light duty trucks .
2 .2 Initial Test
The initial test shall have an overall maximum test time of
200 Seconds.
2.2.1 Preconditioning Mode
The mode timer shall initiate when engine speed is between
2200 and 2800 rpm. The mode shall continue for 30 seconds. If
engine speed falls below 2200 rpm, or exceeds 2800 rpm for more
than five seconds in any one excursion, or 15 seconds over all
excursions, the mode timer shall reset to zero and resume timing.
2.2.2 Idle Mode
This mode shall start immediately following the
preconditioning mode. The mode_t_imer shall startL,,. when the_ vehicle
.^^ J_LQQ upaL "and the_concentration of
six percent ._ The mode shall last a minimum of 30
_
seconds and a maximum of 90 seconds. The idle mode shall continue
as long as engine speed is between 350 and 1100 rpm, CO+C02 level
is above six percent, idle mode time is less than 90 seconds and
passing readings have not been obtained. If engine speed exceeds
1100 rpm or falls below 350 rpm the mode timer shall reset to zero
and resume timing. If the engine stalls the test shall abort. If
CO+C02 falls below six percent at any time, the idle test shall
abort and a prompt to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission Ieve2"3\f or HC and CO shall be
analyzed at a minimum sampling rate of / Hz?) A reading is a simple
average of the emission levels overtime last five seconds.
Readings shall be taken as running averages. If readings less
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than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to the idle emission standards selected for
the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. if all
readings fail for either HC, CO, or both, then the vehicle has
failed the idle mode.
If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
2.3 Second-Chance Test
If the vehicle fails the initial idle test, the test timer
shall reset to zero and a second-chance test shall be performed.
The test shall abort if it cannot be completed before 425 seconds
have elapsed.
2.3.1 Second-Chance Preconditioning Mode
The mode timer shall initiate when engine speed is between
2200 and 2800 rpm. The mode shall continue for 180 seconds. If
engine speed falls below 2200 rpm, or exceeds 2800 rpm for more
than five seconds in any one excursion, or 15 seconds over all
excursions, the mode timer shall reset to zero and resume timing.
2.3.2 Second—Chance Idle Mode
This mode shall start immediately following the
preconditioning mode. The engine shall be shut off and restarted
for 1981-1986 Ford Motor Company products and 1984-1985 Honda
Preludes, but no other vehicles. If necessary to reduce analyzer
fouling, remove the probe from the tailpipe or turn off the sample
pump during the restart procedure.
The mode shall last a minimum of 30 seconds and a maximum of
90 seconds. The mode timer shall start when the vehicle engine
speed is between 350 and 1100 rpm and the concentration of CO+C02
is at least six percent. The idle mode shall continue as long as
engine speed is between 350 and 1100 rpm, CO+C02 level is above six
percent, idle mode time is less than 90 seconds and passing
readings have not been obtained. If engine speed exceeds 1100 rpm
or falls below 350 rpm the mode timer shall reset to zero and
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resume timing. If the engine stalls the test shall abort. If
C0+C02__falls below six percent_at any__time, th_e__jtest _shall abo>f"
an"d a~prompt jTo^ check_ probe__in_se£t_iorr^shaj.l_ occur ."""' " "' ~~""
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to the idle emission standards selected for
the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
readings fail for either HC, CO, or both, then the vehicle has
failed the test.
If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
averaging period).
2.4 Tampering and Safety Testing
Tampering checks and safety inspections, if any, shall be
performed after all emission test sequences are completed.
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2.5 Graphic Illustration of Preconditioned Idle Test
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Table 1
Summary of Preconditioned IdleTes± Parameters
PARAMETER
SPECIFICATION
General Requirements
Minimum probe insertion depth
Minimum CO+C02
Minimum sample rate
Statistical sampling measure
Minimum measurement period
Initial time delay
General Initial Test Requirements
Typical initial test time
Overall maximum initial test time
Initial Preconditioning Mode
Minimum preconditioning engine rpm
Maximum preconditioning engine rpm
Initial preconditioning time limit
Initial Idle Mode
Minimum idle mode time
Maximum idle mode time
Minimum idle engine rpm
Maximum idle engine rpm
10 inches
6%
2 Hz
Simple running average
5 second averaged readings
10 seconds
80-140 seconds
200 seconds
2200 rpm
2800 rpm
30 seconds
30 seconds
90 seconds
350 rpm
1100 rpm
Idle mode sampling algorithm
a) if any readings simultaneously show passing levels for
both HC and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores
of 100 ppm HC and 0.5 percent CO or less, then the
vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall
fail
Idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which
HC + (151*CO) is a minimum, and the start time of these
readings
b) if the vehicle has passed, report the passing readings
for which HC + (151*CO) is a minimum among all passing
readings, and the start time for these readings
General Second-Chance Test Requirements
Typical Second-Chance Test Time
Overall Maximum Second-Chance Test Time
Second-Chance Preconditioning Mode
Second-chance preconditioning time
230-290 seconds
425 seconds
180 seconds
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Second-Chance Idle Mode
Minimum second-chance idle mode time 30 seconds
Maximum second-chance idle mode time 90 seconds
Second-chance idle mode sampling algorithm
a) if any readings simultaneously show passing levels for
both HC and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores
of 100 ppm HC and 0.5 percent CO or less, then the
vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall
fail
Second-chance idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which
HC + (151*CO) is a minimum, and the start time of these
readings
b) if the vehicle has passed, report the passing readings
for which HC + (151*CO) is a minimum among all passing
readings, and the start time for these readings
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3.0 IDLE TEST PROCEDURE
3 . 1 General Requirements
The test sequence shall include at least the following
parameters: HC, CO, C02, and engine rpm. The analyzer shall
prompt the inspector to test the vehicle in as-received condition,
all accessories turned off, and the engine running at normal
operating temperature (based on a temperature gauge reading or a
touch test on the radiator hose, and visual observation for
overheating). The inspector shall insert the sample probe into
the tailpipe and the test sequence shall begin. The test timer
governing the overall test sequence shall start at the start of
sampling. A separate mode timer shall govern the modes within the
test sequence and shall start when the specified conditions are
met. The anti-dilution criterion shall be a minimum combined CO
and C02 concentration of six percent for all light duty vehicles
and light duty trucks.
3.2 Initial Test
The initial idle test shall consist of only the idle mode,
there shall be no preconditioning mode for the initial test. The
initial test shall have an overall maximum test time of 145
seconds.
The mode timer shall start when the engine speed is between
350 and 1100 rpm and the concentration of CO+C02 is at least six
percent. The mode shall last a minimum of 30 seconds and a
maximum of 90 seconds. The idle mode shall continue as long as
engine speed is between 350 and 1100 rpm, CO+C02 level is above six
percent, idle mode time is less than 90 seconds and passing
readings have not been obtained. If engine speed exceeds 1100 rpm
or falls below 350 rpm the mode timer shall reset to zero and
resume timing. If the engine stalls the test shall abort. If
CO + C02 falls below six percent at any time, the test shall abort
and a prompt to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a simple
average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to the idle emission standards selected for
the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
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readings fail for either HC, CO, or both, then the vehicle has
failed the idle mode.
If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
3.3 Second-Chance Test
The vehicle shall be preconditioned prior to the second-
chance idle mode.
3.3.1 Second—Chance Preconditioning Mode
The mode timer shall initiate when engine speed is between
2200 and 2800 rpm. The mode shall continue for 180 seconds. If
engine speed falls below 2200 rpm, or exceeds 2800 rpm for more
than five seconds in any one excursion, or 15 seconds over all
excursions, the mode timer shall reset to zero and resume timing.
3.3.2 Second-Chance Idle Mode
This mode shall start immediately following the
preconditioning mode. The engine shall be shut off and restarted
for 1981-1986 Ford Motor Company products and 1984-1985 Honda
Preludes, but no other vehicles. If necessary to reduce analyzer
fouling, remove the probe from the tailpipe or turn off the sample
pump during the restart procedure.
The mode shall last a minimum of 30 seconds and a maximum of
90 seconds. The mode timer shall start when the vehicle engine
speed is between 350 and 1100 rpm and the concentration of CO+COa
is at least six percent. The idle mode shall continue as long as
engine speed is between 350 and 1100 rpm, CO+C02 level is above six
percent, idle mode time is less than 90 seconds, and passing
readings have not been obtained. If engine speed exceeds 1100 rpm
or falls below 350 rpm the mode timer shall reset to zero and
resume timing. If the engine stalls the test shall abort. If
CO+C02 falls below six percent at any time, the test shall abort
and a prompt to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz . A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
-14-
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mode time, the vehicle shall pass and the mode shall end
immediately .
The pass/fail determination is made based on a comparison of
the HC and CO readings to the idle emission standards selected for
the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
readings fail for either HC, CO, or both, then the vehicle has
failed the test .
If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
average period) .
3 . 4 Tampering and Safety Testing
Tampering checks and safety inspections, if any, shall
performed after all emission test sequences are completed.
3 . 5 Graphic Illustration of the Idle Test
be
2500RPM
JCLE
IDLE MODE
,oncc/-r»ir,o
PRECONDITIONING MODE
(RESTART)
30SECOND 90 SECOND
M.NIMUM
1
IDLE MODE
INITIAL TEST
SECOND-CHANCE TEST
-15-
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Table 2
Summary of Idle Test Parameters
PARAMETER
General Requirements
Minimum probe insertion depth
Minimum CO+C02
Minimum sample rate
Statistical sampling measure
Minimum measurement period
Initial time delay
General Initial Test Requirements
Typical initial test time
Overall maximum initial test time
Initial Idle Mode
Minimum idle mode time
Maximum idle mode time
Minimum idle engine rpm
Maximum idle engine rpm
SPECIFICATION
10 inches
6%
2 Hz
Simple running average
5 second averaged readings
10 seconds
40-100 seconds
145 seconds
30 seconds
90 seconds
350 rpm
1100 rpm
Idle mode sampling algorithm
a) if any readings simultaneously shows passing levels for both HC
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of ICC
ppm HC and 0.5 percent CO or less, then the vehicle shall case
c) if all readings fail for HC or CO, then the vehicle shall fail
Idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
General Second-Chance Test Requirements
Typical Second-Chance Test Time
Overall Maximum Second-Chance Test Time
Second-Chance Preconditioning Mode
Second-chance preconditioning time
Minimum preconditioning engine rpm
Maximum preconditioning engine rpm
Second-Chance Idle Mode
Minimum second-chance idle mode time
Maximum second-chance idle mode time
230-290 seconds
425 seconds
180 seconds
2200 rpm
2800 rpm
30 seconds
90 seconds
-16-
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Second-chance idle mode sampling algorithm
a) if any readings simultaneously show passing levels for both HC
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of IOC
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
Second-chance idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC +
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
-17-
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4 . 0 IDLE TEST PROCEDURE WITH LOADED PRECONDITIONING
4 . 1 General Requirements
The test sequence shall include at least the following
parameters: HC, CO, C02, and dynamometer speed and load. The
analyzer shall prompt the inspector to test the vehicle in as-
received condition, all accessories turned off, and the engine
running at normal operating temperature (based on a temperature
gauge reading or a touch test on the radiator hose, and visual
observation for overheating) . The inspector shall insert the
sample probe into the tailpipe and the test sequence shall begin.
The test timer governing the overall test sequence shall start at
the start of sampling. A separate mode timer shall govern the
modes within the test sequence and shall start when the specified
conditions are met. The anti-dilution criterion shall be a
minimum combined CO and COa concentration of six percent for all
light duty vehicles and light duty trucks.
4 . 2 Initial Test
The initial test shall have an overall maximum test time of
55 seconds. The mode timer shall start when the vehicle is at
idle and the concentration of CO+C02 is at least six percent. The
mode shall last a minimum of 30 seconds and a maximum of 90
seconds. The idle mode shall continue as long as CO+C02 level is
above six percent, idle mode time is less than 30 seconds and
passing readings have not been obtained. If the engine stalls the
test shall abort. If CO+C02 falls below six percent at any time,
the idle test shall abort and a prompt to check probe insertion
shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz . A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the test shall end
immediately .
The pass/fail determination is made based on a comparison of
the HC and CO readings to the idle emission standards selected for
the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
readings fail for either HC, CO, or both, then the vehicle has
failed the idle
If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
-IB-
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the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
4.3 Second-Chance Test
If the vehicle fails the initial idle test, the test timer
shall reset to zero and a second-chance test shall be performed.
The test shall abort if it cannot be completed before 200 seconds
have elapsed.
4.3.1 Second—Chance Preconditioning Mode
The mode timer shall initiate when dynamometer speed is
within the limits specified for the vehicle engine size. The mode
shall continue for a minimum of 30 seconds. If dynamometer speed
falls outside the limits, for more than five seconds in one
excursion, or 15 seconds over all excursions, the mode timer shall
reset to zero and resume timing.
4.3.2 Second-Chance Idle Mode
This mode shall start immediately following the
preconditioning mode.
The mode shall last a minimum of 30 seconds and a maximum of
90 seconds. The mode timer shall start when the vehicle's wheels
are no longer moving and the concentration of CO+C02 is at least
six percent. The idle mode shall continue as long as CO+COa level
is above six percent, idle mode time is less than 90 seconds and
passing readings have not been obtained. If the engine stalls the
test shall abort. If CO+C02 falls below six percent at any time,
the test shall abort and a prompt to check probe insertion shall
occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a simple
average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to the idle emission standards selected
selected for the particular vehicle. If any pair of readings
shows passing scores for both HC and CO when the vehicle has
passed. If all readings fail for either HC, CO, or both, then the
vehicle has failed the test.
-19-
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If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
averaging period).
4.4 Tampering and Safety Testing
Tampering checks and safety inspections, if any, shall be
performed after all emission test sequences are completed.
4.5 Graphic Illustration of Idle Test with Loaded Preconditioning
10 SECOND 30 SECOND 90 SECOND
10 SECOND 30 SECOND 90 SECOND/ yTIME DELAY MINIMUM MAXIMUM
TIME DELAY MINIMUM MAXIMUM N
Et!_LJL_ J - __ - N
IDLE MODE PRECONDITIONING MODE OLE MODE
INITIAL TEST SECONOCHANCE TEST .
-20-
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Table 3
Summary of Idle Test Procedure With Loaded Precondit i nn i n<-r
PARAMETER
SPECIFICATION
General Requirements
Minimum probe insertion depth
Minimum CO+C02
Minimum sample rate
Statistical sampling measure
Minimum measurement period
Initial time delay
General Initial Test Requirements
Typical initial test time
Overall maximum initial test time
Initial Idle Mode
Idle mode time
Minimum idle engine rpm
Maximum idle engine rpm
10 inches
6%
2 Hz
Simple running average
5 second averaged readings
10 seconds
40 seconds
55 seconds
30 seconds
350 rpm
1100 rpm
Idle mode sampling algorithm
a) if any readings simultaneously show passing levels for both
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of
ppm HC and 0.5 percent CO or less, then the vehicle shall
c) if all readings fail for HC or CO, then the vehicle shall
Idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readir.gs,
and the start time for these readings
General Second-Chance Test Requirements
Typical Second-Chance Test Time
Overall Maximum Second-Chance Test Time
Second-Chance Preconditioning Mode
Second-chance preconditioning time
Second-Chance Idle Mode
Minimum second-chance idle mode time
Maximum second-chance idle mode time
80-140 seconds
155 seconds
30 seconds
30 seconds
90 seconds
Second-chance idle mode sampling algorithm
a) if any readings simultaneously shows passing levels for be
and CO, then the vehicle shall pass
-21-
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b) if any readings before the minimum mode time show scores of ICC
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if air readings fail for HC or CO, then the vehicle shall fail
Second-chance idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC +
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
Dynamometer Load-Speed Relationships
Gasoline engine Roll Speed Normal Loading
size (rylinders) (mph) (brake horsepower)
4 or less 22-25 2.8-4.1
5-6 29-32 6.8-8.4
7 or more 32-35 8.4-10.8
-22-
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5.0 PRECONDITIONED TWO SPEED IDLE TEST PROCEDURE
5.1 General Requirements
The test sequence shall include at least the following
parameters: HC, CO, C02, and engine rpm. The analyzer shall
prompt the inspector to test the vehicle in as-received condition,
all accessories turned off, and the engine running at normal
operating temperature (based on a temperature gauge reading or a
touch test on the radiator hose, and visual observation for
overheating). The inspector shall insert the sample probe into
the tailpipe and the test sequence shall begin. The test timer
governing the overall test sequence shall start at the start of
sampling. A separate mode timer shall govern the modes within the
test sequence and shall start when the specified conditions are
met. The anti-dilution criterion shall be a minimum combined CO
and C02 concentration of six percent for all light duty vehicles
and light duty trucks.
5.2 Initial Test
The initial test shall have an overall maximum test time of
290 seconds.
5.2.1"High Speed Mode
The mode timer shall start when engine speed is between 2200
and 2800 rpm and exhaust CO+C02 is at least six percent. The mode
shall last 90 seconds. If engine speed falls below 2200 rpm or
exceeds 2800 rpm for more than two seconds in one excursion, or
more than six seconds over all excursions, within 30 seconds of
final readings, the readings shall be invalid and the mode shall
continue. If CO+C02 falls below six percent at any time, the test
shall abort and a prompt to check probe insertion shall appear.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a simple
average of the emission levels over the last five seconds .
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the test shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to the high speed emission standards
selected for the particular vehicle. If any pair of readings
shows passing scores for both HC and CO then the vehicle has
passed. If all readings fail for either HC, CO, or both, then the
vehicle has failed the high speed mode.
-23-
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If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
5.2.2 Idle Mode
This mode shall be performed immediately following the high
speed mode. The mode timer shall start when the engine speed is
between 350 and 1100 rpm and the concentration of CO+C02 is at
least six percent. This mode shall last a minimum of 30 seconds
and a maximum of 90 seconds. The idle mode shall continue as long
as engine speed is between 350 and 1100 rpm, CO+C02 level is above
six percent, idle mode time is less than 90 seconds, and passing
readings have not been obtained. If engine rpm exceeds 1100 rpm
or falls below 350 rpm the mode timer shall reset to zero and
resume timing. If the engine stalls the test shall abort. If
CO+C02 falls below six percent at any time, the test shall abort
and a prompt to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to idle emission standards selected for the
particular vehicle. If any pair of readings shows passing scores
for both HC and CO then the vehicle has passed. If all readings
fail for either HC, CO, or both, then the vehicle has failed the
idle mode.
If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
-24-
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5.3 Second-Chance Test
If the vehicle fails either mode, the test timer shall
restart and a second-chance test shall be performed. The second
chance test shall be performed for only the mode(s) that failed.
If the vehicle failed only the initial high speed mode the
second chance test shall consist of the high speed test mode only.
The overall test time limit for this sequence is 280 seconds. If
the vehicle failed only the idle mode, the second-chance high
speed mode is for pre-conditioning only. If both modes were
failed initially, a complete test is conducted. However, the
second-chance idle test mode can be skipped if a vehicle has
failed both its initial and second-chance high speed tests. If
the vehicle failed only the idle mode the second chance test shall
consist of the preconditioning mode followed by the idle mode.
The overall test time limit for these sequences shall be 425
seconds.
5.3.1 Second-Chance High Speed Mode-Without Subsequent Idle Mode
The engine shall be shut off and restarted for 1981-1986 Ford
Motor Company products and 1984-1985 Honda Preludes, but no other
vehicles. If necessary to reduce analyzer fouling, remove the
probe from the tailpipe or turn off the sample pump during the
restart procedure.
The mode timer shall start when engine speed is between 2200
and 2800 rpm and exhaust CO+C02 is at least six percent. The mode
shall last a minimum of 30 and a maximum of 180 seconds. If
engine speed falls below 2200 rpm or exceeds 2800 rpm for more
than two seconds in one excursion, or more than six seconds over
all excursions, within 30 seconds of the current final readings,
the readings shall be invalid and the mode shall continue. If
CO + C02 falls below six percent at any time, the test shall abort
and a prompt to check probe insertion shall appear.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz . A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to high speed emission standards selected
for the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
readings fail for either HC, CO, or both, then the vehicle has
failed the test.
-25-
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If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
averaging period).
5.3.2 Second-Chance Preconditioning Mode-With Subsequent Idle Modg
The mode timer shall initiate when engine speed is between
2200 and 2800 rpm. The mode shall continue for 180 seconds. If
engine speed falls below 2200 rpm, or exceeds 2800 rpm for more
than five seconds in any one excursion, or 15 seconds over all
excursions, the mode timer shall reset to zero and resume timing.
5.3.3 Second-Chance Idle Mode
The second-chance idle mode shall be performed immediately
following the second-chance preconditioning mode. The engine
shall be shut off and restarted for 1981-1986 Ford Motor Company
products and 1984-1985 Honda Preludes, but no other vehicles. If
necessary to reduce analyzer fouling, remove the probe from the
tailpipe or turn off the sample pump during the restart procedure.
The mode shall initiate when the engine speed is between 350
and 1100 rpm, and the concentration of CO+C02 is at least six
percent. The mode shall last a minimum of 30 seconds and a
maximum of 90 seconds. The idle mode shall continue as long as
engine speed is between 350 and 1100 rpm, CO+C02 level is above six
percent, idle mode time is less than 90 seconds and passing
readings have not been obtained. If engine rpm exceeds 1100 rpm
or falls below 350 rpm the mode timer shall reset to zero and
resume timing. If the engine stalls the test shall abort. If
CO+C02 falls below six percent at any time, the test shall abort
and a prompt to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to idle emission standards selected for the
particular vehicle. If any pair of readings shows passing scores
for both HC and CO then the vehicle has passed. If all readings
-26-
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fail for either HC, CO, or both, then the vehicle has failed the
test.
If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
averaging period).
5.4 Tampering and Safety Testing
Tampering checks and safety inspections, if any, shall be
performed after all emission test sequences are completed.
-27-
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5.5 graphic Illustration of Prec
\
t
i -I
\
-28-
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Table 4
Summary of Preconditioned Two Speed Idle Test. Procedure Parameter.'
PARAMETER SPECIFICATION
General Requirements
Minimum probe insertion depth
Minimum CO+COs
Minimum sample rate
Statistical sampling measure
Minimum measurement period
Initial time delay
General Initial Test Requirements
Typical Initial Test Time
Overall maximum initial test time
Initial High Speed Mode
High speed mode time
Minimum high speed engine rpm
Maximum high speed engine rpm
10 inches
6%
2 Hz
Simple running average
5 second averaged readings
10 seconds
130-200 seconds
290 seconds
90 seconds
2200 rpm
2800 rpm
High speed mode sampling algorithm
a) if any readings simultaneously show passing levels for both HC
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of 100
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
High speed mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
Initial Idle Mode
Minimum idle mode time
Maximum idle mode time
Minimum idle engine rpm
Maximum idle engine rpm
30 seconds
90 seconds
350 rpm
1100 rpm
Idle mode sampling algorithm
a) if any readings simultaneously show passing levels for both H(
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of 10>
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
Idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -
(151*CO) is a minimum, and the start time of these readings
-29-
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b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
General Second-Chance Test Requirements
Typical second chance test time
a) High Speed only 40-190 seconds
b) Idle only with preconditioning 230-290 seconds
Overall maximum second chance test time
a) High Speed only 280 seconds
b) Idle only with preconditioning 425 seconds
Second-Chance High Speed Mode
Minimum second-chance high speed mode time 30 seconds
Maximum second-chance high speed mode time 180 seconds
Second-chance high speed mode sampling algorithm
a) if any readings simultaneously show passing levels for both HC
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of 100
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
Second-chance high speed mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC *
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
-30-
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Second-Chance Preconditioning Mode
Second-chance preconditioning time limit 180 seconds
Second-Chance Idle Mode
Minimum second-chance idle mode time 30 seconds
Maximum second-chance idle mode time 90 seconds
Second-chance idle mode sampling algorithm
a) if any readings simultaneously show passing levels for
both HC and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores
of 100 ppm HC and 0.5 percent CO or less, then the
vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall
fail
Second-chance idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which
HC + (151*CO) is a minimum, and the start time of these
readings
b) if the vehicle has passed, report the passing readings
for which HC + (151*CO) is a minimum among all passing
readings, and the start time for these readings
-31-
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6 . 0 TWO SPEED IDLE TEST PROCEDURE
6 . 1 C^pneral Requirements
The test sequence shall include at least the following
parameters: HC, CO, C02 , and engine rpm. The analyzer shall
prompt the inspector to test the vehicle in as-received condition,
all accessories turned off, and the engine running at normal
operating temperature (based on a temperature gauge reading or a
touch test on the radiator hose, and visual observation for
overheating) . The inspector shall insert the sample probe into
the tailpipe and the test sequence shall begin. The test timer
governing the overall test sequence shall start at the start of
sampling. A separate mode timer shall govern the modes within the
test sequence and shall start when the specified conditions are
met . The anti-dilution criterion shall be a minimum combined CO
and CO2 concentration of six percent for all light duty vehicles
and light duty trucks.
6.2 Initial Test
The initial test shall have an overall maximum test time of
425 seconds.
6.2.1 Idle Mode
The mode timer shall start when the vehicle engine speed is
between 350 and 1100 rpm and the concentration of CO-I-C02 at least
six percent. The mode shall last a minimum of 30 seconds and a
maximum of 90 seconds. The idle mode shall continue as long as
engine speed is between 350 and 1100 rpm, CO+C02 level is above six
percent, idle mode time is less than 90 seconds and passing
readings have not been obtained. If the engine rpm exceeds 1100
rpm or falls below 350 rpm the mode timer shall reset to zero and
resume timing. If the engine stalls the test shall abort. If
CO + C02 falls below six percent at any time, the idle test shall
abort and a prompt to check probe insertion shall occur.
The pass/fail analysis shall occur after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz . A reading is a simple
average of the emission levels over the last five seconds .
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately .
The pass/fail determination is made based on a comparison of
the HC and CO readings to idle emission standards selected for the
particular vehicle. If any pair of readings shows passing scores
for both HC and CO then the vehicle has passed. If all readings
-32-
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fail for either HC, CO, or both, then the vehicle has failed the
idle mode.
If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
6.2.2 High Speed Mode
The mode timer shall start when engine speed is between 2200
and 2800 rpm and exhaust CO+C02 is at least six percent. The mode
shall last a minimum of 30 seconds and a maximum of 180 seconds.
If engine speed falls below 2200 rpm or exceeds 2800 rpm for more
than two seconds in one excursion, or more than six seconds over
all excursions, within 30 seconds of the current final readings,
the readings shall be invalid and the mode shall continue. If
CO+C02 falls below six percent at any time, the test shall abort
and a prompt to check probe insertion shall appear.
If passing readings have not been obtained after 90 seconds,
1981-1986 Ford Motor Company products and 1984-1985 Honda Preludes
(only) shall be allowed to return to idle, shut off for not more
than 10 seconds and restarted. If necessary to reduce analyzer
fouling, remove the probe from the tailpipe or turn off the sample
pump during the restart procedure. The mode shall resume high
speed operation for the final 90 seconds.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a simple
average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to high speed emission standards selected
for the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
readings fail for either HC, CO, or both, then the vehicle has
failed the test.
If the vehicle passes, the reported scores shall be the
passing readings for which HC + (151*CO) is a minimum among all
passing readings. In addition to storing these readings, the
analyzer shall also store the start time of the readings (i.e.,
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the start of the five second averaging period) . If the vehicle
fails, calculate the scores in the same manner and enter them into
the record. Proceed to the second chance test and report only the
scores obtained from it.
6.3 Second-Chance Test
If and only if the vehicle failed the initial idle mode and
passed the high speed mode, the test timer shall reset and a
second-chance idle test shall be performed. The test shall abort
if it cannot be completed before 145 seconds have elapsed. The
engine shall be shut off and restarted for 1981-1986 Ford Motor
Company products and 1984-1985 Honda Preludes, but no other
vehicles. The analyzer shall either prompt the inspector to
remove the probe during the restart procedure and reinsert it
prior to the start of sampling, or else it shall be programmed to
turn off the sample pump during the restart procedure and turn it
back on for sampling.
The mode timer shall start when the vehicle engine speed and
the concentration of CO+C02 is at least six percent. The mode
shall last a minimum of 30 seconds and a maximum of 90 seconds.
The idle mode shall continue as long as engine speed is between
350 and 1100 rpm, CO+C02 level is above six percent, idle mode time
is less than 90 seconds, and passing readings have not been
obtained. If the engine rpm exceeds 1100 rpm or falls below 350
rpm for more than one second the mode timer shall reset to zero
and resume timing. If the engine stalls the test shall abort. If
CO+C02 falls below six percent at any time, the idle test shall
abort and a prompt to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a simple
average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the mode shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to idle emission standards selected for the
particular vehicle. If any pair of readings shows passing scores
for both HC and CO then the vehicle has passed. If all readings
fail for either HC, CO, or both, then the vehicle has failed the
test.
If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
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the start time of the readings (i.e., the start of the five second
averaging period) .
6 . 4 Tampering and Safety Testing
Tampering checks and safety inspections, if any, shall be
performed after the emission test is complete.
6 . 5 Graphic Illustration of Two Speed Idle
2500 RPM
10 SECOND "**™°
TIME DELAY MINIMUM
1 80 SECONDS BEFORE
SECOND CHANCE
10 SECOND 30 SECOND 90 SECOND .
TIME DELAY MINIMUM MAXIMUM /
IDLE ill I/
IDLE MODE
RESTART AT
90 SECONDS
HGH SPEED MXE
\. 10 SECOND
™£ DELAY
(RESTART) N_
90 SECOND
MAXIMUM
IDLE MODE
INITIAL TEST
SECOND-CHANCE TEST _J
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Table 5
Summary of Two Speed Idle Test. Procedure
PARAMETER
SPECIFICATION
General Requirements
Minimum probe insertion depth
Minimum CO+C02
Minimum sample rate
Statistical sampling measure
Minimum measurement period
Initial time delay
General Initial Test Requirements
Typical Initial Test Time
Overall maximum initial test time
Initial Idle Mode
Minimum idle mode time
Maximum idle mode time
Minimum idle engine rpm
Maximum idle engine rpm
10 inches
6%
2 Hz
Simple running average
5 second averaged readings
10 seconds
80-290 seconds
425 seconds
30 seconds
90 seconds
350 rpm
1100 rpm
Idle mode sampling algorithm
a) if any readings simultaneously show passing levels for both KG
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of '-"„'_
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
Idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
Initial High Speed Mode
Minimum high speed mode time
Maximum high speed mode time
Minimum high speed engine rpm
Maximum high speed engine rpm
30 seconds
180 seconds
2200 rpm
2800 rpm
High speed mode sampling algorithm
a) if any readings simultaneously show passing levels for botn H(
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of 1C!
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fall
High speed mode score reporting algorithm
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a) if the vehicle has failed, report the readings for which HC
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings fo
which HC + (151*CO) is a minimum among all passing readings
and the start time for these readings
General Second-Chance Test Requirements
Typical second chance test time 40-100 seconds
Overall maximum second chance test time 145 seconds
Second-Chance Idle Mode
Minimum second-chance idle mode time 30 seconds
Maximum second-chance idle mode time 90 seconds
Second-chance idle mode sampling algorithm
a) if any readings simultaneously show passing levels for both H1
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of 10
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
Second-chance idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings fo.
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
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7.0 LOADED TEST PROCEDURE
7.1 General Requirements
The test sequence shall include at least the following
parameters: HC, CO, C02, and dynamometer speed and load. The
analyzer shall prompt the inspector to test the vehicle in as-
received condition, all accessories turned off, and the engine
running at normal operating temperature (based on a temperature
gauge reading or a touch test on the radiator hose, and visual
observation for overheating). The inspector shall insert the
sample probe into the tailpipe, and the test sequence shall begin.
The test timer governing the overall test sequence shall start at
the start of sampling. A separate mode timer shall govern the
modes within the test sequence and shall start when the specified
conditions are met. The anti-dilution criterion shall be a
minimum combined CO and C02 concentration of six percent for all
light duty vehicles and light duty trucks.
The initial test shall have an overall maximum test time of
240 seconds.
7.2 Loaded Mode
The mode timer shall start when dynamometer speed is within
the limits specified for the vehicle engine size and the
concentration of CO+C02 is at least six percent. The mode shall
last a minimum of 30 seconds and a maximum of 90 seconds. If
dynamometer speed falls outside the limits for more than two
seconds in one excursion, or six seconds over all excursions,
within 30 seconds of the current final readings, the readings
shall be invalid and the mode shall continue. If CO+C02 falls
below six percent at any time, the test shall abort and a prompt
to check probe insertion shall occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz . A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the test shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to high speed emission standards selected
for the particular vehicle. If any pair of readings shows passing
scores for both HC and CO then the vehicle has passed. If all
readings fail for either HC, CO, or both, then the vehicle has
failed the test.
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If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
averaging period).
7.3 Tdle Mode
The mode timer shall start when the vehicle's wheels have
stopped moving and the concentration of CO+C02 is at least six
percent. The mode shall last a minimum of 30 seconds and a
maximum of 90 seconds. The idle mode shall continue as long as
the CO+CO2 level is above six percent, idle mode time is less than
90 seconds and passing readings have not been obtained. If engine
speed exceeds 1100 rpm or falls below 350 rpm the mode timer shall
reset to zero and resume timing. If the engine stalls the test
shall abort. If CO+C02 falls below six perce-~~ at any time, the
idle test shall abort and a prompt to check p insertion shall
occur.
The pass/fail analysis shall begin after an initial time
delay of 10 seconds. The emission levels for HC and CO shall be
analyzed at a minimum sampling rate of 2 Hz. A reading is a
simple average of the emission levels over the last five seconds.
Readings shall be taken as running averages. If readings less
than or equal to 100 ppm HC and 0.5 percent CO are obtained any
time between the start of the pass/fail analysis and the minimum
mode time, the vehicle shall pass and the test shall end
immediately.
The pass/fail determination is made based on a comparison of
the HC and CO readings to idle emission standards selected for the
particular vehicle. If any pair of readings shows passing scores
for both HC and CO then the vehicle has passed. If all readings
fail for either HC, CO, or both, then the vehicle has failed the
idle mode.
If the vehicle fails, the reported scores shall be the
readings for which HC + (151*CO) is a minimum. If the vehicle
passes, the reported scores shall be the passing readings for
which HC + (151*CO) is a minimum among all passing readings. In
addition to storing these readings, the analyzer shall also store
the start time of the readings (i.e., the start of the five second
averaging period).
7.4 Tampering and Safety Testing
Tampering checks and safety inspections, if any, shall be
performed after the emission test is complete.
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7 .5 Graphic Illust-ration nf the Loaded
LOADED
' ' N 10 SECOND Ma^^jrnj 90 SECOND
/ 30 SECONDS 90 SECONDS >^ TIME DELAY MINIMUM MAXIMUM
IDLE MODE
INITIAL TEST
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Table 6
Summary of Loaded Test Parameters
PARAMETER
SPECIFICATION
General Requirements
Minimum probe insertion depth
Minimum CO+C02
Minimum sample rate
Statistical sampling measure
Minimum measurement period
• Initial time delay
General Initial Test Requirements
Typical Initial Test Time
Overall maximum initial test time
10 inches
6%
2 Hz
Simple running average
5 second averaged readings
10 seconds
80-200 seconds
240 seconds
Loaded Mode
Minimum loaded mode time
Maximum loaded mode time
30 seconds
90 seconds
High speed mode sampling algorithm
a) if any readings simultaneously show passing levels for both HC
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of IOC
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
High speed mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -<
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
Idle Mode
Minimum idle mode time
Maximum idle mode time
30 seconds
90 seconds
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Idle mode sampling algorithm
a) if any readings simultaneously show passing levels for both HC
and CO, then the vehicle shall pass
b) if any readings before the minimum mode time show scores of IOC
ppm HC and 0.5 percent CO or less, then the vehicle shall pass
c) if all readings fail for HC or CO, then the vehicle shall fail
Idle mode score reporting algorithm
a) if the vehicle has failed, report the readings for which HC -
(151*CO) is a minimum, and the start time of these readings
b) if the vehicle has passed, report the passing readings for
which HC + (151*CO) is a minimum among all passing readings,
and the start time for these readings
Dynamometer Load-Speed Relationships
Gasoline engine Roll Speed Normal Loading
size (cylinders) (mph) (brake horsepower)
4 or less 22-25 2 .8-4.1
5-6 29-32 6.8-8.4
7 or more 32-35 8.4-10.8 -
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8.0 GRAPHIC ILLUSTRATION OF TEST PROCEDURES
The following section portrays each of the preceding test
procedures in a graphic form. These are included to assist the
reader in understanding the course each test takes and how they
compare. Each mode is illustrated with line lengths proportional
to its maximum test time. Testing modes are illustrated by solid
lines. Preconditioning modes, and the intervals between modes are
illustrated by broken lines. Key events during the test are
indicated along the way.
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-45-
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77 West Jackson Boulevad ipth
Cfl'ca 60604 ' 12th
F,
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