ASTM D8108-21e1

Standard Test Method for Determination of Particulate Matter Mass from Light Duty Mobile Sources (Gravimetric Method)

SIGNIFICANCE AND USE
5.1 This test method is used to demonstrate compliance with state, EPA as well as relevant international regulations for PM emissions from light-duty vehicles.  
5.1.1 The EPA Tier 3 and CARB LEV III regulations specify FTP and SFTP PM emission standards for light-duty vehicles.
SCOPE
1.1 This test method covers a procedure for the gravimetric determination of particulate matter (PM) collected from diluted light duty vehicle exhaust. It is applicable to mass rates from 0.32 to 32 mg/km (0.2 to 20 mg/mile).  
1.2 Diluted exhaust is passed through pre-weighed filter media which is re-weighed after sampling. The difference in weight is used to determine particulate mass, which is then used with other data to calculate the distance specific emissions.  
1.3 The particulate materials that are measured using this test method are generated by a vehicle following the PM standard applicable portions of the United States Environmental Protection Agency (EPA) and California Air Resources Board (CARB) driving schedules and test procedures for determining the emissions of light duty vehicles. For other jurisdictions, consult regional regulations for applicability of these test procedures. These test procedures are referenced in Annex A3 of this document.  
1.4 The primary intent of this test method is to summarize the PM measurement test procedures as defined by the EPA and CARB (40 CFR Parts §1066, §1065, §86.101, and CARB test procedures for hybrid vehicle testing).  
Note 1: Some requirements are generalized from core references for simplicity and to provide guidance for users applying the principals in this standard to regions not governed by EPA and CARB regulation. For specific details, reference the regulated procedures.  
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Apr-2021
• ICS: 13.040.50 - Transport exhaust emissions
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.03 - Ambient Atmospheres and Source Emissions

Relations

• Refers: ASTM D1356-20a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Sep-2020
• Refers: ASTM D1356-20 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Mar-2020
• Refers: ASTM D1356-15a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Oct-2015
• Refers: ASTM D1356-15 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Jul-2015
• Refers: ASTM D1356-14b - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Dec-2014
• Refers: ASTM D1356-14a - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-May-2014
• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM D1356-14 - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 15-Jan-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM D1356-05(2010) - Standard Terminology Relating to Sampling and Analysis of Atmospheres
• Effective Date: 01-Apr-2010
• Refers: ASTM E177-08 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2008
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008

Overview

ASTM D8108-21e1, titled Standard Test Method for Determination of Particulate Matter Mass from Light Duty Mobile Sources (Gravimetric Method), is an internationally recognized standard developed by ASTM. This standard provides a gravimetric procedure for measuring particulate matter (PM) in the diluted exhaust of light-duty vehicles. The method is key for determining compliance with U.S. Environmental Protection Agency (EPA) and California Air Resources Board (CARB) regulations, as well as other relevant international emissions standards.

Using pre-weighed filters to collect and reweigh exhaust PM, this standard is applicable over a broad range of emissions rates and can be adapted to regional regulatory requirements. Adhering to ASTM D8108-21e1 helps manufacturers and laboratories demonstrate regulatory compliance for PM emissions in light-duty vehicles under real-world driving schedules.

Key Topics

• Scope of Applicability

  • Covers gravimetric measurement of PM from diluted exhaust of light-duty vehicles.
  • Applicable for mass rates from 0.32 to 32 mg/km (0.2 to 20 mg/mile).
  • Primarily references EPA and CARB test cycles, but may be adapted for other regions.

• Test Method Highlights

  • Diluted exhaust is passed through a pre-weighed filter; post-test reweighing determines particulate mass.
  • Strict control of sampling conditions: filter face velocity, sample temperature, dilution factor, and residence time.
  • Ensures prevention of condensation and minimizes sample loss.
  • Use of standardized, non-reactive materials for sample probes, tubing, and filter holders.

• Regulatory Compliance

  • Designed for verification with EPA Tier 3, CARB LEV III, and other international standards.
  • Summarizes PM measurement procedures in reference to 40 CFR §1065, §1066, §86.101, and relevant CARB protocols.
  • Emphasizes proper accounting of interferences and background corrections for accurate PM quantification.

Applications

• Vehicle Certification
  Used by automakers and test laboratories during the emissions certification of new light-duty vehicles to provide regulatory agencies with trustworthy PM emission data.

• Regulatory Compliance Assessment
  Essential for demonstration of compliance with EPA and CARB standards, supporting both ongoing production checks and in-use compliance verifications.

• Emissions Research and Comparative Analysis
  Supports research on the effectiveness of emissions control technologies, and allows comparability of particulate emissions data across vehicle models and technologies.

• International Adaptation

  • While referencing U.S. EPA/CARB protocols, the method may be adapted for global markets by consulting regional regulations and incorporating jurisdiction-specific requirements.

• Industry Best Practices

  • Facilitates harmonization and accuracy in PM emissions measurement, supporting industry best practices and quality control in emissions testing facilities.

Related Standards

• EPA Regulatory References
  • 40 CFR Parts §1066, §1065, §86.101 (emissions testing cycles and procedures)
• CARB Test Procedures
  • California LEV III exhaust emission procedures, including those for hybrid vehicles
• Other ASTM Standards
  • ASTM D1356: Terminology relating to air sampling and analysis
  • ASTM E177: Use of the terms precision and bias in ASTM test methods
  • ASTM E691: Interlaboratory studies for test method precision
• ISO Standards
  • ISO 14644-1: Cleanroom standards for air cleanliness
• International Trade Principles
  • Developed according to WTO TBT Committee principles, ensuring broad recognition and international acceptance

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Keywords: ASTM D8108-21e1, particulate matter mass, gravimetric method, light-duty vehicle emissions, PM emissions compliance, EPA Tier 3, CARB LEV III, emissions test method, international standards, exhaust particulate measurement, regulatory compliance.

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
´1
Designation: D8108 − 21
Standard Test Method for
Determination of Particulate Matter Mass from Light Duty
Mobile Sources (Gravimetric Method)
This standard is issued under the fixed designation D8108; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Research report information was updated editorially in July 2022.
1. Scope priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This test method covers a procedure for the gravimetric
1.7 This international standard was developed in accor-
determinationofparticulatematter(PM)collectedfromdiluted
dance with internationally recognized principles on standard-
light duty vehicle exhaust. It is applicable to mass rates from
ization established in the Decision on Principles for the
0.32 to 32 mg/km (0.2 to 20 mg/mile).
Development of International Standards, Guides and Recom-
1.2 Diluted exhaust is passed through pre-weighed filter
mendations issued by the World Trade Organization Technical
media which is re-weighed after sampling. The difference in
Barriers to Trade (TBT) Committee.
weight is used to determine particulate mass, which is then
used with other data to calculate the distance specific emis- 2. Referenced Documents
sions. 2
2.1 ASTM Standards:
1.3 The particulate materials that are measured using this D1356 Terminology Relating to Sampling and Analysis of
test method are generated by a vehicle following the PM Atmospheres
standard applicable portions of the United States Environmen- E177 Practice for Use of the Terms Precision and Bias in
tal Protection Agency (EPA) and California Air Resources ASTM Test Methods
Board (CARB) driving schedules and test procedures for E691 Practice for Conducting an Interlaboratory Study to
determining the emissions of light duty vehicles. For other Determine the Precision of a Test Method
jurisdictions, consult regional regulations for applicability of 2.2 ISO Standards:
these test procedures. These test procedures are referenced in
ISO 14644-1 Cleanrooms and associated controlled environ-
Annex A3 of this document.
ments — Part 1: Classification of air cleanliness by
particle concentration
1.4 The primary intent of this test method is to summarize
2.3 Government Regulations:
thePMmeasurementtestproceduresasdefinedbytheEPAand
CARB California Exhaust Emission Standards and Test
CARB (40 CFR Parts §1066, §1065, §86.101, and CARB test
Procedures for 2018 and Subsequent Model Zero-
procedures for hybrid vehicle testing).
Emission Vehicles and Hybrid Electric Vehicles, in the
NOTE 1—Some requirements are generalized from core references for
Passenger Car, Light-Duty Truck and Medium-Duty Ve-
simplicity and to provide guidance for users applying the principals in this
hicle Classes – Sections F (HEVs) and G (PHEVs)
standard to regions not governed by EPA and CARB regulation. For
EPA 40 CFR Part 86, Appendix I
specific details, reference the regulated procedures.
EPA 40 CFR Part 86.101
1.5 The values stated in SI units are to be regarded as
EPA 40 CFR Part 1065
standard. The values given in parentheses after SI units are
provided for information only and are not considered standard.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
1.6 This standard does not purport to address all of the
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
safety concerns, if any, associated with its use. It is the
Standards volume information, refer to the standard’s Document Summary page on
responsibility of the user of this standard to establish appro-
the ASTM website.
Available from International Organization for Standardization (ISO), ISO
Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
This test method is under the jurisdiction of ASTM Committee D22 on Air Geneva, Switzerland, http://www.iso.org.
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient Available from California Air Resources Board (CARB), 1001 I Street,
Atmospheres and Source Emissions. Sacramento, CA 95814, https://ww2.arb.ca.gov.
Current edition approved May 1, 2021. Published May 2021. Originally AvailablefromUnitedStatesEnvironmentalProtectionAgency(EPA),William
approved in 2020. Last previous edition approved in 2020 as D8101 – 20. DOI: Jefferson Clinton Bldg., 1200 Pennsylvania Ave., NW, Washington, DC 20460,
10.1520/D8108-21E01. http://www.epa.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
D8108 − 21
EPA 40 CFR Part 1066 3.2.10.1 Discussion—For flow through a tube it is defined
by the relationship:
3. Terminology
Re number 5 2vρr⁄µ
3.1 Definitions—For definitions of terms used in this test
where the parameters are:
method, refer to Terminology D1356.
µ = viscosity,
3.2 Definitions of Terms Specific to This Standard:
ρ = density,
3.2.1 driving schedule, n—a series of vehicle speeds that a
v = velocity, and
vehicle must follow during a test.
r = radius.
3.2.1.1 Discussion—Driving schedules are specified in 40
CFR Part 86. 3.2.10.2 Discussion—Details on applying Reynolds number
3.2.1.2 Discussion—Adriving schedule may consist of mul- can be found in 40 CFR Parts 1065 and 1066; reference 40
tiple test intervals or phases. For jurisdictions not governed by CFR 1065.640(d) and 40 CFR 1066.110(b)(1)(viii).
the CFR, please refer to local or regional requirements.
3.2.11 SC03, n—the test cycle specified in Appendix I,
3.2.2 duty cycle, n—a set of weighting factors and the
paragraph (h), of 40 CFR Part 86.
correspondingtestcycles,wheretheweightingfactorsareused
3.2.12 SFTP, n—the collection of test cycles as given in 40
to combine the results of multiple test intervals into a compos-
CFR 1066.801(c)(2).
ite result.
3.2.13 standard reference conditions, n—the following:
3.2.3 federal test procedure (FTP), n—one of the following:
3.2.13.1 Standard pressure is 101.325 kPa.
3.2.3.1 The test cycle consisting of one urban dynamom-
3.2.13.2 Standard temperature is 293.15 K.
eter driving schedule (UDDS) as specified in paragraph (a) of
Appendix I of 40 CFR Part 86, followed by a 10-minute soak 3.2.14 test interval, n—a period over which a vehicle’s
with the engine off and repeat driving through the first 505 emission rates are determined separately.
seconds of the UDDS. See 40 CFR 1066.801(c)(1). 3.2.14.1 Discussion—For many standards, compliance with
the standard is based on a weighted average of the mass
3.2.3.2 The entire test procedure for measuring exhaust or
emissions from multiple test intervals. For example, 40 CFR
evaporative emissions, or both, as described in 40 CFR
Part 86 may specify a complete duty cycle as a cold-start test
1066.801(c).
interval and a hot-start test interval. In cases where multiple
3.2.4 light duty vehicles, n—chassis certified vehicles under
test intervals occur over a duty cycle, the standard-setting part
6364 kg (14 000 pounds) gross vehicle weight rating (GVWR)
may specify additional calculations that weight and combine
as regulated under CARB LEV III and EPATier 3 standards.
results to arrive at composite values for comparison against the
3.2.5 particulate matter (PM), n—material collected on the
applicable standards.
filter under EPA 40 CFR Parts 1065 and 1066 sampling
3.2.15 test weight, n—meaning given in 40 CFR
conditions.
1066.410(h) or §1066.805.
3.2.5.1 Discussion—PM can include solid carbon, ash,
3.2.16 urban dynamometer driving schedule (UDDS),
semi-volatile organic material, semi-volatile inorganic
n—the test cycle specified in Appendix I, paragraph (a), of 40
material, etc.
CFR Part 86.
3.2.6 Phase 1, n—relating to the first 505 seconds of the
3.2.17 US06, n—the test cycle specified in Appendix I,
FTP cold-start test interval.
paragraph (g), of 40 CFR Part 86.
3.2.6.1 Discussion—Note that the term Phase 1 may also
apply to measurement of constituents that are not collected in
3.3 Acronyms:
a phase, such as PM and continuously measured total hydro-
3.3.1 CFV, n—critical flow venturi
carbons (THC).
3.3.2 CH4, n—methane
3.2.7 Phase2,n—relatingtothelast867secondsoftheFTP
3.3.3 CO, n—carbon monoxide
cold-start test interval.
3.3.4 CO2, n—carbon dioxide
3.2.8 Phase 3, n—relating to the first 505 seconds of the
FTP hot-start test interval. 3.3.5 CVS, n—constant volume sampler
3.2.9 Phase4,n—relatingtothelast867secondsoftheFTP 3.3.6 NMHC, n—non-methane hydrocarbons
hot-start test interval, if run.
3.3.7 PDP, n—positive displacement pump
3.2.9.1 Discussion—NotethatPhase2dataisgenerallyused
3.3.8 PFSS, n—partial flow sampling system
in place of running Phase 4 for a three-phase FTP.
3.3.9 SSV, n—subsonic venturi
3.2.10 Reynolds number, n—an experimental number which
3.3.10 THC, n—total hydrocarbons
is the ratio of inertial forces to viscous forces.
3.3.11 V ,n—total diluted volume, corrected for any
mix
40 CFR 1066.1 sample removed
´1
D8108 − 21
4. Summary of Test Method Background sampling time should be representative of the
durationofthetestintervaltowhichthebackgroundcorrection
4.1 To measure particulate matter emissions during exhaust
is applied.
emissions tests, a sample stream of raw or dilute exhaust is
6.1.2 Background PM may be sampled from the dilution
extracted for a measured period of time at a controlled flow
tunnel at any time before or after an emission test using the
rate. The volume of exhaust sample is measured and the
same sampling system used during the emission test. For this
particulate matter entrained in the exhaust sample is also
background sampling, the dilution tunnel blower must be
measured by collection on a pre-weighed filter, which is then
turned on, the vehicle must be disconnected from the labora-
PM-stabilized and reweighed. The increase in filter mass is
tory exhaust tubing, and the laboratory exhaust tubing must be
attributed to particulate matter collected from the sampled
capped. This PM blank test in combination with the dilute
exhaust. The ratio of the mass of the particulate matter
exhaust flow verification (propane check) may be performed as
collected to the volume of exhaust sampled allows for the
long as the exhaust tubing inlet to the CVS has a HEPAfilter.
calculation of the exhaust particulate concentration. This con-
6.1.3 The duration of the background sample may be
centration is used along with other recorded test signals to
different than that of the test cycle to which the background
calculate the distance-specific emissions of particulate matter.
correction is to be applied, consistent with good engineering
4.2 Valid measurements can be achieved only when:
judgment.
4.2.1 Dilution air has been added to the raw exhaust such
6.1.4 PM background correction may not exceed 5 µg or
that the overall dilution factor of the extracted sample is within 5 % of the net PM mass expected at the standard, whichever is
the range specified in 7.6.2.
greater.
4.2.2 Asample probe is used with a single opening oriented
to face directly upstream. 7. PM Sampling Apparatus
4.2.3 The PM filter face velocity remains less than
7.1 Overview—Vehicle PM mass is gravimetrically deter-
140 cm⁄s.
mined by operating the vehicle over a prescribed drive cycle
4.2.4 ThePMfiltersampletemperatureasspecifiedin7.6.1.
inside an environmentally controlled emissions testing labora-
4.2.5 The sampling train is designed and operated to avoid
tory. The PM is collected either with a sample from the raw
condensation and to be leak free;. exhaust pipe (partial flow where the extracted sample is
diluted) or from a full flow tunnel where the entire vehicle
4.2.6 Good engineering judgment is used to ensure that
exhaust volume is diluted. A small sample of the vehicle’s
selected procedures and equipment do not cause significant
diluted exhaust is proportionally extracted then flowed through
loss of PM from the sample.
a high efficiency fine mesh filter. The PM emissions are
deposited on this filter. The amount of PM collected on the
5. Significance and Use
filter is then gravimetrically determined by subtracting the
5.1 Thistestmethodisusedtodemonstratecompliancewith
post-test (loaded) PM filter weight from tared or pre-test
state, EPA as well as relevant international regulations for PM
(clean) filter weight, both after buoyancy correction. This net
emissions from light-duty vehicles.
mass is then proportionally increased to reflect the total PM
5.1.1 The EPA Tier 3 and CARB LEV III regulations
mass emitted from the vehicle.
specify FTP and SFTP PM emission standards for light-duty
vehicles.
DILUTED OR RAW EXHAUST PM SAMPLER
7.2 Wetted Sample Materials—It is recommend that heated
6. Interferences and PM Background Correction
sample transfer lines/enclosures are used to minimize tempera-
6.1 Background particulate matter mass in the dilution ture differences between transfer lines and exhaust constituents
tunnel may result in a positive interference. The background and prevent condensation or deposition. Use inert materials
PM mass in the dilution tunnel may be measured, and
that are electrically conductive on the inside surfaces to collect
accounted for in the test results. PM such as 300 series stainless steel. Small amounts of inert
polymers (for example, polytetrafluoroethylene (PTFE)) are
6.1.1 PM background is not required to be measured during
allowed for gaskets, valve seals, etc. as well as short sections
every test. PM background correction may be applied for a
of flexible non-conductive tubing to connect to the vehicle’s
single site or multiple sites using a moving-average back-
tailpipe.
ground value as long as the background PM sample media (for
example, filters) were all made by the same manufacturer from
7.3 Sample Probe—Extract a representative PM sample
the same material. Use good engineering judgment to deter-
eitherfromtheCVSfullflow“tunnel,”orfromthevehicleraw
mine how many background samples make up the moving
exhaust pipe (partial flow sampling systems – PFSS).
average and how frequently to update those values. For
example, one background sample per week may be collected
and averaged along with previous background values, main-
40 CFR 1066.110 (b)(2)(i)(A)
taining five observations for each calculated average value. 9
40 CFR 1066.110 (b)(2)(i)(B)
40 CFR 1066.110 (b)(2)(i)(C)
40 CFR 1066.110 (b)(2)(i)(D)
40 CFR 1065.145(d)(2)
7 13
40 CFR 1066.110 (b)(2)(i)) and §1066.605 (f) 40 CFR 1066.110(b)(1)(iv)
´1
D8108 − 21
7.3.1 For any pair of flow rates, use recorded sample and graph 40 CFR 1066.110(b)(2)(iii)(A) to prevent or limit
total flow rates, where total flow rate means the raw exhaust aqueous condensation is allowed. Dilution gas may be condi-
flow rate for raw exhaust sampling and the dilute exhaust flow tioned (dehumidified or heated) before diluting the PM sample
rate for CVS sampling, or their 1 Hz means with the statistical to avoid aqueous condensation.
calculations as for example described in 40 CFR 1065.602. 7.5.5 Control dilution gas temperature to 15 – 52 °C.
Determine the standard error of the estimate, SEE, of the
7.6 Operational Parameters:
sample flow rate versus the total flow rate. For each test
7.6.1 Control sample temperature to 47 6 5 °C tolerance, as
interval, demonstrate that SEE was less than or equal to 3.5 %
measured anywhere within 20 cm upstream or downstream of
of the mean sample flow rate. 27
the PM filter.
7.3.1.1 Maintain sample proportionality to the total flow of
7.6.2 The total time weighted dilution factor is required to
diluted exhaust or raw exhaust. For any pair of flow rates, use
be 7:1 – 20:1. The maximum DF of 20:1 is generally not
recorded sample and total flow rates, where total flow rate
applicable to hybrid electric vehicle or plug-in hybrid electric
means the raw exhaust flow rate for raw exhaust sampling and
vehicles (HEV/PHEVs) emissions since the dilution factor is
the dilute exhaust flow rate for CVS sampling, or their 1 Hz
infinite when the engine is off; however it is strongly recom-
means to demonstrate that each flow rate was constant within
mendtostayunderthespecifiedmaximumdilutionfactorlimit
62.5 % of its respective mean or target flow rate.
when the engine is running. To determine the overall dilution
7.3.1.2 Pressure control, maintain static pressure at the
factor for PM samples utilizing secondary dilution gas, multi-
location where raw exhaust is introduced into the tunnel within
ply the dilution factor from the CVS by the dilution ratio of
61.2 kPa of atmospheric pressure. 28
secondary dilution gas to primary diluted exhaust.
7.3.2 Use PM probes with a single opening at the end.
7.6.3 Secondary dilution may be used as needed to meet
7.3.3 Orient PM probes to face directly upstream and be
total dilution factor. It may also be used to control the sample
radially centered.
temperature prior to the filter media.
7.3.4 Shielding a PM probe’s opening with either a PM
7.6.4 Filter face flow velocity shall be no more than
pre-classifier such as a hat, or utilizing a pre-classifier further 29
140 cm⁄second.
downstream is allowed, but not both.
7.6.5 Net filter PM mass gain shall be no more than
7.3.5 It is recommend that the inside diameter of PM probes 30
400 µg.
is sized to approximate isokinetic sampling at the expected
7.6.6 PM sample residence time from 1st dilution point up
mean flow rate.
to the filter is 1.0 – 5.5 seconds, with a residence time of at
7.4 Direct Vehicle Exhaust (DVE)—For PFSS, utilize a least 0.50 s from the final dilution point to the filter. If PM is
direct vehicle exhaust volume measurement to maintain PM collected on a single filter for either a 3 phase or 4 phase FTP,
sampleproportionalityandforcalculatingtotalexhaustvolume the overall residence time of 5.5 s may be exceeded for sample
to determine vehicle PM emissions. It is recommended that flow rates below the highest expected flow rate.
high accuracy ultrasonic technology with a frequency response 7.6.7 All PM sampler flowrates, sample flowrate, dilution
of at least 5 hertz for this measurement is used to match the air flowrate, and filter flow rate must be set to meet all the
PFSS data recording and control minimum frequencies. requirements of the EPA test method.
7.5 Exhaust Dilution Gas for PM Measurement: 7.7 Filter Holder—Use a filter holder with a 12.5° (from
7.5.1 Exhaust gases must be diluted at least once (primary) center) divergent cone angle to transition from the transfer-line
before sampling onto the PM filter. (See 7.6.2.) For full flow inside diameter to the exposed diameter of the filter face.
dilution, the sample extracted from the CVS tunnel can be
7.8 Pre-Classifier:
diluted a second time (secondary) as needed.
7.8.1 An inertial impactor or a cyclonic separator is used to
7.5.2 Dilution gas may be ambient air, purified air, or
remove at least 50 % of PM at an aerodynamic diameter of 10
nitrogen.
µm and no more than1%ofPMatan aerodynamic diameter
7.5.3 It is recommended to filter all dilution gas sources
of 1 µm over the range of flow rates used. Install the
with high-efficiency particulate (HEPA) filters with an initial
pre-classifier in the dilution system downstream of the last
minimum collection efficiency specification of 99.97 %.
dilution stage. Locate PM sample media within 75 cm down-
7.5.4 In addition to the allowances in 40 CFR
stream of the pre-classifier’s exit.
1065.140(c)(6), heating the dilution air as described in para-
7.9 Transporting PM Filters—Transfer the PM filters/
cassette from the test site to a weigh room in an individual
40 CFR 1065.545(a) and 1066.425(g)(1)
15 25
40 CFR 1065.545(b) and 1066.425(g)(1) 40 CFR 1065.140(b)
16 26
40 CFR 1065.140(c)(2) 40 CFR 1066.110(b)(2)(iii)(A)
17 27
40 CFR 1065.145(c)(3) 40 CFR 1065.140(e)(4)
18 28
40 CFR 1065.145(c)(3) 40 CFR 1066.110(b)(2)(iii)(B)
19 29
40 CFR 1065.145(c)(3) 40 CFR 1066.110(b)(2)(iii)(C)
20 30
40 CFR 1065.145(c)(3) 40 CFR 1065.170(a)(2)
21 31
40 CFR 1066.125 Table 1 40 CFR 1065.140(e)(3)
22 32
40 CFR 1065.140(a) 40 CFR 1066.815(b)
23 33
40 CFR 1065.140(a) 40 CFR 1065.170(c)(1)(v)
24 34
40 CFR 1065.140(b)(3) 40 CFR 1065.145(f)(1)
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D8108 − 21
FIG. 1 PM Filter Cassette Specifications
containerthatiscoveredorsealedtopreventcommunicationof 7.13 PM Filters:
semi-volatile matter from one filter to another. 7.13.1 The filter must be circular, with an overall diameter
of 46.50 6 0.6 mm and an exposed surface diameter of at least
7.10 Filter Cassette and Backing Screen—Use a clean
38 mm.
cassette and a fine mesh supporting screen designed to the
7.13.2 The filter must have a minimum initial collection
specifications of Figure 1 of 40 CFR 1065.170. The cassette
efficiency of 99.7 %.
must be made of one of the following materials: acetal, 300
7.13.3 It is highly recommended that a pure PTFE filter
series stainless steel, polycarbonate, acrylonitrile-butadiene-
36 materialthatdoesnothaveanyflow-throughsupportbondedto
styrene (ABS) resin, or conductive polypropylene.
the back and has an overall thickness of 40 6 20 µm be used.
7.11 See Fig. 1.
An inert polymer ring may be bonded to the periphery of the
7.12 Background PM Sampler: filter material for support and for sealing between the filter
cassette parts. Polymethylpentene (PMP) and PTFE are inert
7.12.1 Collecting and measuring background (tunnel) PM
concentrations under the same conditions diluted exhaust PM materials commonly used as a support ring, but other inert
materials may be used. The use of PTFE-coated glass fiber
is collected and measured is recommended or measure them in
a way that does not affect compliance with applicable stan- filter material is permitted, as long as this filter media selection
does not affect the ability to demonstrate compliance with the
dards. For example, the following simplifications for back-
ground sampling may be used. applicable standards.
7.12.1.1 Proportional sampling requirements may be disre-
7.14 Exhaust Collection System:
garded.
7.14.1 It is important to minimize the lengths of exhaust
7.12.1.2 Unheated PM sampling systems may be used.
tubing used in this test method. No more than 4 m total length
of exhaust tubing without heat or insulation may be used. A
total length of laboratory exhaust tubing up to 10 m may be
40 CFR 1065.170(c)(1)(viii)
36 39
40 CFR 1065.170(c)(1)(vii) 40 CFR 1065.170(c)(1)(ii)
37 40
40 CFR 1065.170 Figure 1 40 CFR 1065.170(c)(1)(i)
38 41
40 CFR 1065.140(b)(2) 40 CFR 1065.170(c)(1)(iii)
´1
D8108 − 21
TABLE 1 Summary of Equipment Specifications That Apply for
used provided that insulation or heating, or both, of the tubing
A
Chassis Testing
is performed to minimize the temperature difference between
40 CFR Part 1065
the exhaust gas and the tubing wall over the course of the
Applicability for Chassis Testing Under This Part
References
emission test. The laboratory exhaust tubing length is defined
40 CFR 1065.140 Use all except as noted:
as starting at the end of the vehicle’s tailpipe and ends at the
 40 CFR 1065.140(b) applies as described in Sec-
tion 7.
first sample point or the first dilution point. The laboratory
 Use 40 CFR 1065.140(c)(6), with the additional al-
exhaust tubing may include flexible sections, but it is recom-
lowance described in Section 7.
mended that it be limited to the shortest length of flexible
 Do not use 40 CFR 1065.140(d)(2)(iv).
 Use 40 CFR 1065.140(e)(1) as described in this
tubing practicable. For multiple-tailpipe configurations where
section.
the tailpipes combine into a single flow path for emission
 Do not use 40 CFR 1065.140(e)(2).
sampling, the start of the laboratory exhaust tubing may be
40 CFR 1065.145 Use all except 40 CFR 1065.145(b).
taken at the last joint where the exhaust flow first becomes a
single, combined flow.
40 CFR 1065.150 Use all.
7.14.2 Insulationorheatinganylaboratoryexhausttubingis
40 CFR 1065.170 Use all except as noted:
permitted.
 Use 40 CFR 1065.170(c)(1)(vi) as described in
7.14.3 Use laboratory exhaust tubing materials that are
Section 7.
smooth-walled and not chemically reactive with exhaust gases
40 CFR 1065.190 Use all.
and particles. Nominally smooth spiral-style and accordion-
A
40 CFR 1066.110 Table 1
style flexible tubing are considered to be smooth-walled.
Materials must also be electrically conductive. Series 300
stainless steel is an acceptable material for testing. Short
sections of nonconductive flexible tubing may be used to
7.15 PM Filter Stabilization and Weighing Environments:
connect a PM sampling system to the vehicle’s tailpipe; use
7.15.1 PM Filter stabilization and weighing environments
good engineering judgment to limit the amount of nonconduc-
may share a common space or be separate.
tive surface area exposed to the vehicle’s exhaust.
7.15.1.1 Contaminants—The weighing and stabilization en-
7.14.4 It is recommend that laboratory exhaust tubing that
vironment should be kept free of ambient contaminants, such
has either a wall thickness of less than 2 mm or is air
as dust, aerosols, or semi volatile materials. The recommended
gap-insulated to minimize temperature differences between the
conformity is to Class Six clean room specifications in accor-
wall and the exhaust is used.
dance with ISO 14644-1.
7.14.5 Electrically ground the entire exhaust system, with
7.15.1.2 Ambient Conditions and Tolerances—The weigh-
the exception of nonconductive flexible tubing.
ing environment temperature shall be maintained to
7.14.6 For vehicles with multiple tailpipes, route the ex-
22 °C 6 1 °C, and the stabilization environment to
haust into a single flow and ensure proper mixing.
22 °C 6 3 °C if it’s a separate room or chamber, and to
7.14.7 Aremote mix tee, which dilutes the exhaust closer to
22 °C 6 1 °C if both environments are shared. Maintain dew-
the tailpipe may be used.
point to 9.5 °C with a recommended tolerance of 61 °C for
7.14.8 Route the exhaust gases to a dilution tunnel.
both environments if the expected fraction of sulfuric acid in
7.14.9 Whether sampling PM emissions from the raw ex-
PM is unknown. The recommended maximum air-supply and
haust pipe (PFSS) or from the tunnel, ensure mixing of raw
return velocities in the weighing environment are 0.05 m⁄s.
exhaust gases in the transfer tube before sampling (PFSS), and
7.15.1.3 Verification of Ambient Conditions—Continuously
likewise in the tunnel and with dilution gas.
measure dewpoint, temperature, and atmospheric pressure.
7.14.10 It is recommended that the diluted or raw exhaust
Confirm dewpoint and temperature are within tolerances at
stream at the first sampling point has a Reynolds number, Re#,
least 60 minutes before weighing filters.
>4000,whereRe#isbasedontheinsidediameterofthetunnel
7.15.1.4 Reference Filters—Verify cleanliness of the PM
or the raw exhaust transfer tube, as appropriate.
stabilization environment by use of reference filters as de-
7.14.11 Summary of applicable 40 CFR Part 1065 equip-
scribed in 8.3.
ment specifications. (See Table 1.)
7.15.1.5 StaticElectricity—Staticelectricityshouldbemini-
mized by electrically grounding the balance, using 300 series
stainlesssteeltweezers,usingagroundingstrapfortweezersor
operator which will enable a common ground with balance,
and using a static electricity neutralizer. Static electricity
40 CFR 1066.110(b)(1)(i)
neutralizers include radioactive neutralizers such as Polonium
40 CFR 1066.110(b)(1)(iii)
210,andotherneutralizerssuchascoronadischargeionizers.It
40 CFR 1066.110(b)(1)(iv)
is also recommended to monitor static voltage of the sample
40 CFR 1066.110(b)(1)(v)
40 CFR 1066.110(b)(1)(vii)
media, and to neutralize the media to within 62V of neutral.
40 CFR 1066.110(b)(1)(viii)
7.15.2 Gravimetric Balance—Follow procedures defined in
40 CFR 1066.110(b)(2)(v)
40 CFR 1065.190 and 1065.290.
40 CFR 1065.140(c)
40 CFR 1066.110(b)(1)(viii)
40 CFR 1065.140(c)(3)
52 53
40 CFR 1066.110(c) 40 CFR 1065.190
´1
D8108 − 21
7.15.2.1 Installation—It is recommended to install the bal- the containers with the top portion of the cassette removed
ance so that it is isolated from external noise and vibration, during the stabilization period.
preferably on a vibration isolation platform. An electrically
8.2 Balance Verifications:
grounded static dissipating draft shield to shield the balance
8.2.1 Independent Verifications—The balance performance
from convective airflow is also recommended.
shall be verified by the balance manufacturer (or representative
7.15.2.2 Balance Requirements—Balances should meet
approved by said manufacturer) within 370 days of testing/
specifications of in Table 1 of 40 CFR 1065.205, linearity
weighing any filter.
requirements in 40 CFR 1065.307, and internal or external
8.2.2 Zero and Span—The balance performance shall be
calibration weight requirements in 40 CFR 1065.790.
confirmed by zero and span within 12 hours before weighing
7.15.2.3 Pan Design—The balance pan design should mini-
any filter. This may be done either manually with at least one
mize corner loading of the balance by centering the sample
calibration weight within the expected range of the total filter
media on the weighing pan and locating the sample as low as
weight, or use an automated procedure such as a balance that
possible.
automatically verifies performance with internal calibration
7.16 PM Data Updating, Recording, and Control—See 40
weights.
CFR 1066.125.
8.2.2.1 PM Balance Calibration Weights—PM balance cali-
bration weights shall be certified as NIST-traceable within
7.17 PM Measurement Instrument Calibrations and
0.1 % uncertainty by any calibration lab that maintains NIST-
Verifications—For example, as stated in 40 CFR 1066.130.
traceability. Make sure the highest calibration weight has no
7.18 PM Linearity Verification—For example, as stated in
greater than ten times the mass of an unused PM-sample
40 CFR 1066.135.
medium.
7.19 Tolerance, Range, and 95 % Rule:
8.3 Reference Sample Weighing—Verify all mass readings
7.19.1 Interpretation of ranges. Interpret a range as a toler-
during a weighing session by weighing reference PM sample
ance unless explicitly identified as an accuracy, repeatability,
media (for example, filters) before and after a weighing
linearity, or noise specification in this part, two types of ranges
session. A weighing session shall be no longer than 80 hours,
are specified.
and may include both pre-test and post-test mass readings.
7.19.1.1 Type (1)—Whenever a range is specified by a
Weighing sessions are recommended to be eight hours or less.
single value and corresponding limit values above and below
Successive mass determinations of each reference PM sample
that value (such as X 6 Y), target the associated control point
media (for example, filter) must return the same value within
to that single value (X). Examples of this type of range include
610 µg or 610 % of the net PM mass expected at the standard
“610 % of maximum pressure,” or “(30 6 10) kPa.” In these
(if known), whichever is higher. If successive reference PM
examples, target the maximum pressure or 30 kPa.
sample media (for example, filter) weighing events fail this
7.19.1.2 Type (2)—Whenever a range is specified by the
criterion, invalidate all individual test media (for example,
interval between two values, one may target any associated
filter) mass readings occurring between the successive refer-
controlpointtoanyvaluewithinthatrange.Anexampleofthis
ence media (for example, filter) mass determinations. These
type of range is “(40 to 50) kPa.”
media (for example, filter) may be reweighed in another
7.19.1.3 Tolerancemeanstheintervalinwhichatleast95%
weighing session. If a pre-test media (for example, filter) mass
of a set of recorded values of a certain quantity must lie. Use
determination is invalidated, that test interval is void.
the specified recording frequencies and time intervals to
8.3.1 Reference Filter Weighing—A minimum of two refer-
determine if a quantity is within the applicable tolerance. The
ence filters of the same material and size as sample filters are
concept of tolerance is intended to address random variability.
required. Follow weighing procedures outlined in 8.4. If mean
Do not take advantage of the tolerance specification to incor-
values are used for reference filters, mean values for sample
porate a bias into a measurement.
filters must be used also.
8. Filter Weighing 8.4 Sample and Reference Filter Weighing—Follow the
filter handling, filter stabilization and balance verification
8.1 Filter Handling and Stabilization:
requirements described above prior to, or during the weighing
8.1.1 Filter Handling—Visually inspect filters prior to test
process.
for defects and discard defective filters. Handle filters with 300
8.4.1 Weigh filters manually or automatically according to
series stainless steel tweezers. Tweezers or operator should be
equipment manufacturers specifications. Substitution weighing
grounded to prevent static electricity (see 7.15).
is recommended, especially for manual weighing. See 8.5.
8.1.2 Filter Stabilization—Filters shall be stabilized for a
8.4.2 Correct for Buoyancy—Both pre-test and post-test
minimum of 30 minutes in a PM stabilization environment
filters shall be corrected for buoyancy as described in 8.6.
prior to either pre- or post-test weighing. During this time the
8.4.3 Repeat Measurements—Measurements may be re-
environment must be within the criteria specified in 7.15.
peated to determine mean mass for each filter. Use good
Filtersmayeitherberemovedfromsealedcontainersorkeptin
engineering judgement to remove outliers from mean values.
40 CFR 1065.20(f)
55 56
40 CFR 1065.1001 40 CFR 1065.390
´1
D8108 − 21
A
TABLE 2 Summary of Standard Requirements as in Accordance with Reference
Equipment and Sampling
Reference Criteria Location
Parameters
40 CFR 1066.110(b)(1)(i) Transfer Pipe Electrically conductive, < 10 m, <4 m with out heating or insulation 7.14
40 CFR 1066.110(b)(2)(i) PM Background Correction Greater of < 5 µg or 5 % of standard 6.1
40 CFR 1066.110(b)(2)(iii) PM Filter Sample Temp. 47±5°C 7.6.1
40 CFR 1066.110(b)(2)(iii) Total Dilution Factor (7:1 – 20:1) with exception on 20:1 for hybrids 7.6.2
40 CFR 1066.420(f)(2) Aqueous Condensation Prevent or limit 7.5.4; 10.3
40 CFR 1066.110(b)(2)(iii) and (iv) Dilution Air Temp. 15 to 52 °C 7.5.5
40 CFR 1066.815(b) PM Overall Residence Time 1.0 to 5.5 seconds. Exception to 5.5 in accordance with 40 CFR 7.6.6
1066.815(b)
40 CFR 1066.110(c) (Table 1) PM Secondary Residence Time > 0.5 seconds 7.6.6
40 CFR 1066.110(c) (Table 1) Raw Exhaust Pressure ± 1.2 kPa of atmospheric 7.3.1
40 CFR 1066.125 (Table 1) Data Recording (PM temps, etc.) Minimum 1 Hz 7.3.1
40 CFR 1066.130 (Table 1) PM Leak Verification < 0.5 % flow rate or ± 0.5 % span concentration
40 CFR 1065.170(a)(2) Net PM Mass < 400 µg
40 CFR 1066.420(c)(1) Ambient Temperature 20–30 °C (or as required by test cycle)
40 CFR 1066.420(d)(1) Ambient Humidity “50 gr/lb H O” (7.1 g water/kg dry air) (or as required by test cycle)
40 CFR 1066.425(g) PM Proportionality Flow rate ± 2.5 % of mean 7.3.1
40 CFR 1066.425(g)(2) PM Weighing and Stabilization Temp: 22±1°C, dewpoint: 9.5±1°C 7.15.1.2
40 CFR 1066.815(b) PM Filter Face Velocity < 140 cm/s 7.6.4
A
Other jurisdictions may have requirements.
8.4.4 Net Mass—Subtract the buoyancy corrected mass of where:
the pre-test filter from the buoyancy corrected mass of the
m = PM mass corrected for buoyancy,
cor
post-test filter. Use the net PM mass in emission calculations.
m = PM mass uncorrected for buoyancy,
uncor
ρ = density of air in balance environment,
air
8.5 Substitution Weighing—Substitution weighing is recom-
ρ = density of calibration weight used to span balance,
weight
mended to correct for balance zero drift. It uses a reference
and
weight measured before and after each weighing of sample
ρ = density of PM sample media, such as a filter.
media
media. When used, it shall be used for both pre-test and
post-test measurement. The substitution weight shall meet the
8.6.2 Filter Density—For PTFE coated borosilicate glass,
requirements of a calibration weight as specified in 40 CFR
use a density of 2300 kg/m . For PTFE membrane with an
1065.790, and must be same density as the weight used to span
integral support ring composed of polymethylpentene that
the balance, and should be similar in mass to an unused filter.
accounts for 95 % of media mass, use a density of 920 kg/m .
Use the following procedure or develop a different procedure
For PTFE membrane with an integral support ring of PTFE,
using good engineering judgement.
use a density of 2144 kg/m .
8.5.1 Procedure—Weigh the substitution weight, weigh the
8.6.3 Air Density—Use the following equation to calculate
sample filter, and weigh the substitution weight again. Calcu-
air density. One may use nominal constant values for tempera-
late the arithmetic mean of two substitution weight readings,
ture and humidity in the equation, as the balance environment
andsubtractthemeanfromthesamplereadingandaddthetrue
tightly controls temperature, and humidity has an insignificant
mass of the substitution weight from the calibration weight
impact:
certificate.Apply the buoyancy correction to the sample filters,
ρ ·M
abs mix
and also for the substitution weight if its density is less than
ρ 5 (2)
air
3 R·T
amb
2.0 g⁄cm .
where:
8.6 BuoyancyCorrection—Correctfiltersfortheirbuoyancy
in air based on the filter density, density of the air and the ρ = absolute pressure in balance environment,
abs
M = molar mass of air in balance environment,
density of the calibration.
mix
R = molar gas constant, and
8.6.1 Buoyancy Correction Equation—Use following equa-
T = absolute ambient temperature of balance
amb
tion to correct for buoyancy:
environment.
ρ
air
1 2
ρ 8.6.4 Calibration Weight Density—Use the stated density of
weight
m 5 m · (1)
cor uncor
ρ the calibration weight.
air
1 2
ρ
media
9. Standard Requirements
40 CFR 1065.590 9.1 See Table 2.
´1
D8108 − 21
10. Calculations
x = amount of C1-equivalent NMHC measured in the
NMHC
sample over the test interval.
10.1 Background—This section describes the calculations
x = amount of CH4 measured in the sample over the
CH4
used to determine PM emission rates. PM measurement and
test interval.
reporting are required in accordance with FTP, US06, and
x = amountofCOmeasuredinthesampleoverthetest
CO
SC03 tests. For light duty vehicles, mass based exhaust
interval.
emission calculations are used, although molar based calcula-
α = atomic hydrogen-to-carbon ratio of the test fuel.
tions are optional. Molar based calculations in 40 CFR 1065
Measureα or use default values fromTable 1 of 40
are required for heavy duty engine certifications. In this test
CFR 1065.655.
method, only mass based PM emission calculations are given
β = atomic oxygen-to-carbon ratio of the test fuel.
since almost all light duty manufacturers use these for their
Measureβ or use default values fromTable 1 of 40
light duty testing and certification. Exhaust emission standards
CFR 1065.655.
are set in g/mile (or g/km) for all emission constituents
10.3.3 The dilution factor DF over the test interval for
including PM.
partial-flow dilution sampling systems can be calculated using
FTP PM MASS CALCULATION Eq. 40 CFR 1066.610-3:
V
10.2 PM testing of light duty vehicles is performed on a
dexhstd
DF 5
V
chassis dynamometer where vehicle speed is controlled to exhstd
followaprescribeddutycyclewhilesimulatingvehicledriving
(Eq. 40 CFR 1066.610-3)
through the dynamometer’s road-load settings. Exhaust emis-
where:
sion standards are set over test intervals or drive schedules, or
both, as follows: V = total dilute exhaust volume sampled over the test
dexhstd
interval, corrected to standard reference
10.2.1 Vehicle Operation—Testing involves measuring PM
conditions, and
emission mass in grams and distance in kilometres or miles
V = total exhaust volume sampled from the vehicle,
travelled while operating the vehicle on a chassis dynamom- dexhstd
corrected to standard reference conditions.
eter. Note that a single drive schedule such as the FTP may
have multiple test intervals and require cold/hot weighting of
10.3.4 Thetimeweighteddilutionfactor,DF ,fortheentire
w
results from multiple test intervals to calculate a composite
test or duty cycle can be calculated using Eq. 40 CFR
distance-based emission value to compare to the PM standard.
1066.610-4:
N
10.3 Dilution Factor Requirement—Dilution is required to
t
i
(
prevent or limit water condensation from occurring within the
i51
58 DF 5
w N
sampling system. It is also required to ensure proper condi-
·t
i
(
tions for PM formation. Valid tests must ensure a time
DF
i51 i
weighted overall dilution factor as specified in 7.6.2.
(Eq. 40 CFR 1066.610-4)
10.3.1 The total mass of PM over a test interval is deter-
mined by continuously sampling diluted vehicle tailpipe ex- where:
haust and flowing through a filter in a PM sampler while
N = number of test intervals,
maintaining the filter face temperature specified in 7.6.1. The
i = test interval number,
dilution factor in full flow and the dilution ratio in partial flow t = duration of test interval, and
must stay within the limits specified in 7.6.2. DF = dilution factor over the test interval.
10.3.2 The dilution factor for full flow CVS can be calcu-
10.4 The filter face velocity can be set up to a maximum
lated using Eq. 40 CFR 1066.610-2.
valueof140cm/sectoincreasefilterloadingasdescribedin40
CFR 1066.110(b)(2)(iii)(C) for example. The extracted sample
DF5
shall be proportional to the raw or dilute exhaust flow rate, as
applicable depending on whether testing is conducted under
α α β
1 1 1 3.76 · 1 1 2 · x 1 x 1 x 1 x
S S DD ~ !
CO2 NMHC CH4 CO
full flow or partial flow sampling. The filter shall be condi-
2 4 2
tioned and stabilized in a weighing chamber or in a PM
(Eq. 40 CFR 1066.610-2)
stabilization environment for a minimum of 30 minutes before
and after the test. The environmental conditions in the
where:
weighing chamber or the PM stabilization environment are
controlled according to 40 CFR 1065.190. The PM filter
x = amount of CO2 measured in the sample over the
CO2
masses must be corrected for sample media buoyancy as
test interval.
describedin40CFR1065.690(see8.6).ThefiltersampledPM
40 CFR Part 1065.260
58 62
40 CFR Part 1066.420(f)(2) 40 CFR Part 1065.260, 265, 267
59 63
40 CFR Part 1066.801 40 CFR Part 1065.250
60 64
40 CFR Part 1065.250 40 CFR 1065.590 and 1065.595
´1
D8108 − 21
concentration is multiplied by the total (raw or dilute) flow used for HEV testing to maintain the initial state of charge of
from which it was extracted during the test interval. This the battery by the end of the test. PM sampling can be done
product is the total mass of the emitted PM during the test using any of the procedures specified later in this section as
interval. Options1to5. CalculationoftheemissionmassofPM,m ,
PM
is dependent on how many PM filters are used in the test. For
FTP PM FLOW SAMPLING OPTIONS
procedures involving flow weighting, the filter face velocity
should be set to a weighting target of 1.0 not to exceed
10.5 There are several options available in 40 CFR Part
1066 for light duty vehicle FTP PM testing. The two main 140 cm⁄sec.Allow filter face velocity to decrease as a percent-
age of the weighting factor if the weighting factor is less than
options for PM testing are full flow and partial flow:
10.5.1 Full flow sampling with a constant volume sampler 1.0 and do not change the nominal CVS flowrates or secondary
dilution ratios between FTP or UDDS test intervals. If PM is
(CVS) where the entire vehicle exhaust is diluted in a full flow
dilution tunnel. being collected using the procedures specified in Options 4 or
5 below, the residence time requirements of 7.6.6 apply.
10.5.2 Partialflowsamplingwhereasmallpercentageofthe
exhaust is extracted by the PM sampler while maintaining 10.8.3 Option 1:
proportionality to exhaust
...