(a) The provisions of this part do not apply to engines used in medium-duty passenger vehicles that are subject to regulation under 40 CFR part 86, subpart S, except as specified in 40 CFR part 86, subpart S, and Sec. 1036.108(a)(4). For example, this exclusion applies for engines used in vehicles certified to the standards of 40 CFR 1037.104.
(b) Engines installed in heavy-duty vehicles that do not provide motive power are nonroad engines. The provisions of this part therefore do not apply to these engines. See 40 CFR part 1039, 1048, or 1054 for other requirements that apply for these auxiliary engines. See 40 CFR part 1037 for requirements that may apply for vehicles using these engines.
(c) The provisions of this part do not apply to aircraft or aircraft engines. Standards apply separately to certain aircraft engines, as described in 40 CFR part 87.
(d) The provisions of this part do not apply to engines that are not internal combustion engines. For example, the provisions of this part do not apply to fuel cells.
(e) The provisions of this part do not apply to engines used in heavy-duty vehicles that are subject to light-duty greenhouse gas standards under 40 CFR part 86, subpart S, except as specified in 40 CFR part 86, subpart S, and Sec. 1036.108(a)(4). [76 FR 57381, Sept. 15, 2011, as amended at 78 FR 36389, June 17, 2013]