Amendments to In-UseTesting for
Heavy-Duty Diesels, Measurement
and Instrumentation, and Off-Highway
Engine Regulations
The U.S. Environmental Protection Agency (EPA) is publishing a
Direct Final Rulemaking to make several amendments to EPA's
mobile source emission standards and test procedures. These revisions
affect the in-use particulate matter (PM) testing program for heavy-
duty diesel engines, locomotives, spark-ignition (SI) marine engines,
small SI engines, Tier 4 nonroad diesel engines, and PM measurement
and assessment for both laboratory and field testing.
Overview
This Direct Final Rule makes several revisions to EPA's mobile source emission
standards and test procedures including the heavy-duty diesel engine in-use testing
program. The amendments are as follows:
• EPA adopted a final accuracy margin for PM for portable emission measure'
ment systems that resulted from a comprehensive research program. This final
PM accuracy margin will replace the interim emission measurement "accuracy"
margin for the requisite portable emission measurement devices,
• Delay enforcement of the PM in-use testing program for heavy-duty diesel
engines until 2011,
• Grant flexibilities for heavy-duty diesel engine manufacturers to complete
testing obligations under PM pilot program,
• Clarify the analytical requirements for in-use PM measurement as a result of
lessons learned in the research program,
• Clarify acceptable accounting protocols for emission control system regenera-
tion events when calculating not-to-exceed (NTE) results,
• Allow fuel rate information derived from the engine control module (ECM)
to determine NTE mass emission rate during in-use testing,
SEPA
United States
Environmental Protection
Agency
Office of Transportation and Air Quality
EPA-420-F-10-042
October 2010
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A set of minor changes will affect categories of highway and nonroad engines,
• Allow partial flow dilution sampling for transient test cycle PM measurement,
• Extend interim flexibilities for locomotives,
• Allow later notification deadline for small'volume manufacturers of marine SI engines to
qualify for a delay in the new exhaust emission standards,
• Revise the phase-in provisions for the Tier 4 nonroad emission standards to allow manu-
facturers to use oxides of nitrogen and non-methane hydrocarbon (NOx+NMHC)
credits to show compliance,
• Amend the transitional flexibilities program for manufacturers of specialized higlvaltitude
equipment,
• Correct former errors in the E2 Ramped Modal Cycle,
• Clarify applicable exclusions for small SI engines installed in nonhandheld equipment.
Public Participation Opportunities
This rule is being released as a Direct Final Rule. However, comments can be submitted under
a parallel Notice of Proposed Rulemaking (NPRM). Comments will be accepted for 30 days
beginning when the NPRM is published in the Federal Register. All comments should be
identified by Docket ID No. EPA-HQ-OAR-2010-0142 and submitted by one of the following
methods:
Internet: www.regulations.gov
E-mail: a'and'r'Docket@epa.gov
Mail:
Environmental Protection Agency
Mail Code 2822T
1200 Pennsylvania Avenue NW
Washington, DC 20460
Hand Delivery:
U.S. Environmental Protection Agency
EPA Headquarters Library
EPA West Building
Room 3334
1301 Constitution Avenue NW
Washington, DC
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For More Information
You can access the rule and related documents on EPA's Office of Transportation and Air
Quality (OTAQ) Web site at:
www.epa.gov/otaq/hd'hwy.htm
For more information on this Direct Final Rule, please contact the Assessment and Standards
Division at:
U.S. Environmental Protection Agency
Assessment and Standards Division
Office of Transportation and Air Quality
2000 Traverwood Drive
Ann Arbor, MI48105
Voice-mail: (734) 214-4636
E-mail: asdinfo@epa.gov
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