[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: 40CFR1048.230] [Page 566-567] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 1048_CONTROL OF EMISSIONS FROM NEW, LARGE NONROAD SPARK-IGNITION ENGINES--Table of Contents Subpart C_Certifying Engine Families Sec. 1048.230 How do I select engine families? (a) Divide your product line into families of engines that are expected to have similar emission characteristics throughout the useful life. Your engine family is limited to a single model year. (b) Group engines in the same engine family if they are the same in all of the following aspects: (1) The combustion cycle. (2) The cooling system (water-cooled vs. air-cooled). (3) Configuration of the fuel system (for example, fuel injection vs. carburetion). (4) Method of air aspiration. (5) The number, location, volume, and composition of catalytic converters. (6) The number, arrangement, and approximate bore diameter of cylinders. (7) Evaporative emission controls. (c) You may subdivide a group of engines that is identical under paragraph (b) of this section into different engine families if you show the expected emission characteristics are different during the useful life. (d) You may group engines that are not identical with respect to the things listed in paragraph (b) of this section in the same engine family if you show that their emission characteristics during the useful life will be similar. (e) You may create separate families for exhaust emissions and evaporative emissions. If we do this, list both families on the emission control information label. (f) Where necessary, you may divide an engine family into sub- families to meet different emission standards, as specified in Sec. 1048.101(a)(2). For issues related to compliance and prohibited actions, we will generally apply decisions to the whole engine family. For engine labels and other administrative [[Page 567]] provisions, we may approve your request for separate treatment of sub- families. [70 FR 40473, July 13, 2005]