40 C.F.R. § 86.007-15 : PROTECTION OF ENVIRONMENT — ENVIRONMENTAL PROTECTION AGENCY — AIR PROGRAMS — CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES — GENERAL PROVISIONS FOR HEAVY-DUTY ENGINES AND HEAVY-DUTY VEHICLES —15 - NO[x] and particulate averaging, trading, and banking for heavy-duty engines

Section 86.007-15 includes text that specifies requirements that differ from §86.004-15. Where a paragraph in §86.004-15 is identical and applicable to §86.007-15, this may be indicated by specifying the corresponding paragraph and the statement "[Reserved]. For guidance see §86.004-15."

(a) -(l) [Reserved]. For guidance see §86.004-15.
(m) The following provisions apply for model year 2007 and later engines (including engines certified during years 2007-2009 under the phase-in provisions of §86.007-11(g)(1), §86.005-10(a), or §86.008-10(f)(1) ). These provisions apply instead of the provisions of paragraphs §86.004-15 (a) through (k) to the extent that they are in conflict.
(1) Manufacturers of Otto-cycle engines may participate in an NMHC averaging, banking and trading program to show compliance with the standards specified in § 86.008-10. The generation and use of NMHC credits are subject to the same provisions in paragraphs §86.004-15(a) through (k) that apply for NO X plus NMHC credits, except as otherwise specified in this section.
(2) Credits are calculated as NO X or NMHC credits for engines certified to separate NO X and NMHC standards. NO X plus NMHC credits (including banked credits and credits that are generated during years 2007-2009 under the phase-in provisions of §86.007-11(g)(1), §86.005-10(a), or §86.008-10 (f)(1)) may be used to show compliance with 2007 or later NO X standards (NO X or NMHC standards for Otto-cycle engines), subject to an 0.8 discount factor (e.g., 100 grams of NO X plus NMHC credits is equivalent to 80 grams of NO X credits).
(3) NO X or NMHC (or NO X plus NMHC) credits may be exchanged between heavy-duty Otto-cycle engine families certified to the engine standards of this subpart and heavy-duty Otto-cycle engine families certified to the chassis standards of subpart S of this part, subject to an 0.8 discount factor (e.g., 100 grams of NO X (or NO X plus NMHC) credits generated from engines would be equivalent to 80 grams of NO X credits if they are used in the vehicle program of subpart S, and vice versa).
(4) Credits that were previously discounted when they were banked according to paragraph (c) of §86.004-15, are subject to an additional discount factor of 0.888 instead of the 0.8 discount factor otherwise required by paragraph (m)(2) or (m)(3) of this section. This results in a total discount factor of 0.8 (0.9 * 0.888 = 0.8).
(5) For diesel engine families, the combined number of engines certified to FELs higher than 0.50 g/bhp-hr using banked NO X (and/or NO X plus NMHC) credits in any given model year may not exceed 10 percent of the manufacturer's U.S.-directed production of engines in all heavy-duty diesel engine families for that model year.
(6) The FEL must be expressed to the same number of decimal places as the standard (generally, one-hundredth of a gram per brake horsepower-hour). For engines certified to standards expressed only one-tenth of a gram per brake horsepower-hour, if the FEL is below 1.0, then add a zero to the standard in the second decimal place and express the FEL to nearest one-hundredth of a gram per brake horsepower-hour.
(7) Credits are to be rounded to the nearest one-hundredth of a Megagram using ASTM E29-93a (Incorporated by reference at §86.1 ).
(8) Credits generated for 2007 and later model year diesel engine families, or generated for 2008 and later model year Otto-cycle engine families are not discounted (except as specified in paragraph (m)(2) or (m)(3) of this section), and do not expire.
(9) For the purpose of using or generating credits during a phase-in of new standards, a manufacturer may elect to split an engine family into two subfamilies (e.g., one which uses credits and one which generates credits). The manufacturer must indicate in the application for certification that the engine family is to be split, and may assign the numbers and configurations of engines within the respective subfamilies at any time prior to the submission of the end-of-year report required by §86.001-23.
(i) Manufacturers certifying a split diesel engine family to both the Phase 1 and Phase 2 standards with equally sized subfamilies may exclude the engines within that split family from end-of-year NO X (or NO X +NMHC) ABT calculations, provided that neither subfamily generates credits for use by other engine families, or uses banked credits, or uses averaging credits from other engine families. All of the engines in that split family must be excluded from the phase-in calculations of §86.007-11(g)(1) (both from the number of engines complying with the standards being phased-in and from the total number of U.S.-directed production engines.)
(ii) Manufacturers certifying a split Otto-cycle engine family to both the Phase 1 and Phase 2 standards with equally sized subfamilies may exclude the engines within that split family from end-of-year NO X (or NO X +NMHC) ABT calculations, provided that neither subfamily generates credits for use by other engine families, or uses banked credits, or uses averaging credits from other engine families. All of the engines in that split family must be excluded from the phase-in calculations of §86.008-10(f)(1) (both from the number of engines complying with the standards being phased-in and from the total number of U.S.-directed production engines.)
(iii) Manufacturers certifying a split engine family may label all of the engines within that family with a single NO X or NO X +NMHC FEL. The FEL on the label will apply for all SEA or other compliance testing.
(iv) Notwithstanding the provisions of paragraph (m)(9)(iii) of this section, for split families, the NO X FEL shall be used to determine applicability of the provisions of §§86.007-11(a)(3)(ii), (a)(4)(i)(B), and (h)(1), and 86.008-10 (g).
(10) For model years 2007 through 2009, to be consistent with the phase-in provisions of §86.007-11(g)(1), credits generated from engines in one diesel engine service class (e.g., light-heavy duty diesel engines) may be used for averaging by engines in a different diesel engine service class, provided the credits are calculated for both engine families using the conversion factor and useful life of the engine family using the credits, and the engine family using the credits is certified to the standards listed in §86.007-11(a)(1). Banked or traded credits may not be used by any engine family in a different service class than the service class of the engine family generating the credits.

40 C.F.R. § 86.007-15

66 FR 5163, 1/18/2001