contains_description: "Containing a codification of documents of general applicability and future effect"
publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"
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(a)For purposes of certification, divide your product line into families of engines that are expected to have similar emission characteristics throughout the useful life as described in this section. You may not group Category 1 and Category 2 engines in the same family.
(b)In general, group engines in the same engine family if they are the same in all the following aspects:
(1)The combustion cycle and fuel (the fuels with which the engine is intended or designed to be operated).
(2)The cooling system (for example, raw-water vs. separate-circuit cooling).
(c)Alternatively, you may ask us to allow you to include other engine configurations in your engine family, consistent with good engineering judgment.
(d)Do not include in your family any configurations for which good engineering judgment indicates that your emission controls are unlikely to provide PM emission reductions similar to the configuration(s) tested.