§ 86.004-26 Mileage and service accumulation; emission measurements.

(a)–(b) [Reserved]

(c)

(1) Paragraph (c) of this section applies to heavy-duty engines.

(2) Two types of service accumulation are applicable to heavy-duty engines, as described in paragraphs (c)(2)(i) and (ii) of this section. For Otto-cycle heavy-duty engines exhaust emissions, the service accumulation method used by a manufacturer must be designed to effectively predict the deterioration of emissions in actual use over the full useful life of the of the candidate in-use vehicles and must cover the breadth of the manufacturer's product line that will be covered by the durability procedure. Manufacturers not selecting Options 1 or 2 described in § 86.005–10(f) may certify Otto-cycle engines using the provisions contained in § 86.094–26(c)(2) rather than those contained in this paragraph (c)(2) for 2004 model year engine families certified using carry-over durability data, except for those engines used for early credit banking as allowed in § 86.000–15(k).

(i) Service accumulation on engines, subsystems, or components selected by the manufacturer under § 86.094–24(c)(3)(i). The manufacturer determines the form and extent of this service accumulation, consistent with good engineering practice, and describes it in the application for certification.