Sections 1065.1131 through 1065.1145 specify procedures for aging compression-ignition engine aftertreatment systems in an accelerated fashion to produce an aged aftertreatment system for durability demonstration. Determine the target number of hours that represents useful life for an engine family as described in the standard setting part. The method described is a procedure for translating field data that represents a given application into an accelerated aging cycle for that specific application, as well as methods for carrying out aging using that cycle. The procedure is intended to be representative of field aging, includes exposure to elements of both thermal and chemical aging, and is designed to achieve an acceleration of aging that is ten times a dynamometer or field test (1,000 hours of accelerated aging is equivalent to 10,000 hours of standard aging).

(a) Development of an application-specific accelerated aging cycle generally consists of the following steps:

(1) Gathering and analysis of input field data.

(2) Determination of key components for aging.

(3) Determination of a thermal deactivation coefficient for each key component.

(4) Determination of potential aging modes using clustering analysis.

(5) Down-selection of final aging modes.

(6) Incorporation of regeneration modes (if necessary).

(7) Cycle generation.

(8) Calculation of thermal deactivation.

(9) Cycle scaling to reach thermal deactivation.

(10) Determination of oil exposure rates.

(11) Determination of sulfur exposure rates.

(b) There are two methods for using field data to develop aging cycles, as described in § 1065.1139(b)(1) and (2). Method selection depends on the type of field data available. Method 1 directly uses field data to generate aging modes, while Method 2 uses field data to weight appropriate regulatory duty cycles that are used for emissions certification.

(c) Carry out accelerated aging on either a modified engine platform or a reactor-based burner platform. The requirements for these platforms are described in § 1065.1141 for engine bench aging and § 1065.1143 for burner-based bench aging.