[Code of Federal Regulations]

[Title 40, Volume 31]

[Revised as of July 1, 2006]

From the U.S. Government Printing Office via GPO Access

[CITE: 40CFR1039.525]



[Page 510-511]

 

                   TITLE 40--PROTECTION OF ENVIRONMENT

 

         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)

 

PART 1039_CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD 

COMPRESSION-IGNITION ENGINES--Table of Contents

 

                        Subpart F_Test Procedures

 

Sec.  1039.525  How do I adjust emission levels to account for 

infrequently regenerating aftertreatment devices?



    This section describes how to adjust emission results from engines 

using aftertreatment technology with infrequent regeneration events. For 

this section, ``regeneration'' means an intended event during which 

emission levels change while the system restores aftertreatment 

performance. For example, exhaust gas temperatures may increase 

temporarily to remove sulfur from adsorbers or to oxidize accumulated 

particulate matter in a trap. For this section, ``infrequent'' refers to 

regeneration events that are expected to



[[Page 511]]



occur on average less than once over the applicable transient duty cycle 

or ramped-modal cycle, or on average less than once per typical mode in 

a discrete-mode test.

    (a) Developing adjustment factors. Develop an upward adjustment 

factor and a downward adjustment factor for each pollutant based on 

measured emission data and observed regeneration frequency. Adjustment 

factors should generally apply to an entire engine family, but you may 

develop separate adjustment factors for different engine configurations 

within an engine family. If you use adjustment factors for 

certification, you must identify the frequency factor, F, from paragraph 

(b) of this section in your application for certification and use the 

adjustment factors in all testing for that engine family. You may use 

carryover or carry-across data to establish adjustment factors for an 

engine family, as described in Sec.  1039.235(d), consistent with good 

engineering judgment. All adjustment factors for regeneration are 

additive. Determine adjustment factors separately for different test 

segments. For example, determine separate adjustment factors for hot-

start and cold-start test segments and for different modes of a 

discrete-mode steady-state test. You may use either of the following 

different approaches for engines that use aftertreatment with infrequent 

regeneration events:

    (1) You may disregard this section if regeneration does not 

significantly affect emission levels for an engine family (or 

configuration) or if it is not practical to identify when regeneration 

occurs. If you do not use adjustment factors under this section, your 

engines must meet emission standards for all testing, without regard to 

regeneration.

    (2) If your engines use aftertreatment technology with extremely 

infrequent regeneration and you are unable to apply the provisions of 

this section, you may ask us to approve an alternate methodology to 

account for regeneration events.

    (b) Calculating average adjustment factors. Calculate the average 

adjustment factor (EFA) based on the following equation:



EFA = (F)(EFH) + (1-F)(EFL)



Where:



F = the frequency of the regeneration event in terms of the fraction of 

tests during which the regeneration occurs.

EFH = measured emissions from a test segment in which the 

regeneration occurs.

EFL = measured emissions from a test segment in which the 

regeneration does not occur.



    (c) Applying adjustment factors. Apply adjustment factors based on 

whether regeneration occurs during the test run. You must be able to 

identify regeneration in a way that is readily apparent during all 

testing.

    (1) If regeneration does not occur during a test segment, add an 

upward adjustment factor to the measured emission rate. Determine the 

upward adjustment factor (UAF) using the following equation:



UAF = EFA - EFL



    (2) If regeneration occurs or starts to occur during a test segment, 

subtract a downward adjustment factor from the measured emission rate. 

Determine the downward adjustment factor (DAF) using the following 

equation:



DAF = EFH - EFA



    (d) Sample calculation. If EFL is 0.10 g/kW-hr, 

EFH is 0.50 g/kW-hr, and F is 0.1 (the regeneration occurs 

once for each ten tests), then:



EFA = (0.1)(0.5 g/kW-hr) + (1.0 - 0.1)(0.1 g/kW-hr) = 0.14 g/

    kW-hr.

UAF = 0.14 g/kW-hr - 0.10 g/kW-hr = 0.04 g/kW-hr.

DAF = 0.50 g/kW-hr - 0.14 g/kW-hr = 0.36 g/kW-hr.