(a) Certification compliance shall be demonstrated as follows:

(1) Test procedure and emission results. The emission test to be used is the heavy-duty engine Federal Test Procedure as set forth in the applicable portions of part 86 of this chapter or an approved alternative test procedure prescribed under §85.1414. Certification emission testing must be carried out using representative production equipment as provided in paragraph (b) of this section. The test results must demonstrate that the retrofit/rebuild equipment will comply with either the particulate emission requirements of §§85.1403(b)(1)(i) or 85.1403(b)(2)(i), or provide some level of particulate emission reduction, and will not cause the urban bus engine to fail to meet any applicable Federal emission requirements set for that engine in the applicable portions of 40 CFR part 86, provided the equipment is properly installed.

(2) Emission test engine selection.

(i) The test engine used must represent the “worst case” with respect to particulate emissions of all those engine configurations for which the retrofit/rebuild equipment is being certified. The worst case engine configuration shall be the engine configuration having the highest engine-out particulate matter emission levels, when properly maintained and used, prior to installation of the retrofit/rebuild equipment. EPA reserves the right to request data or information showing that the particulate emission reduction efficiency of the retrofit/rebuild equipment being certified under this paragraph, for use with more than one engine family, does not vary significantly among the engine families.

(ii) The results of certification tests using the worst case engine selections made in this section shall be applicable for the other engine configurations for which the retrofit/rebuild equipment is designed.

(iii) The worst case test engine selected for certification emission testing is not required to meet Federal emission standards before the retrofit/rebuild equipment is installed. However, each test engine shall have representative emissions performance that is close to the standards and have no obvious or suspected emission defects. Each test engine shall be tuned properly and set to the engine manufacturer's specifications before testing is performed. Any excessively worn or malfunctioning emission related part shall be repaired or replaced with a new part prior to testing.

(iv) To demonstrate compliance with the particulate emission requirements of §85.1403(b)(1)(i), the test engine used may be a new unused engine, an in-use engine that has been rebuilt previously, or an in-use engine that has not been rebuilt previously.

(v)

(A) To demonstrate compliance with the particulate emission requirements of §85.1403(b)(2)(i) on engines for which particulate certification data exists, the test engine used may be a new unused engine, an in-use engine that has been rebuilt previously, or an in-use engine that has not been rebuilt previously.

(B) To demonstrate compliance with the particulate emission requirements of §85.1403(b)(2)(i) on engines for which no particulate certification data exists, the test engine used may be a new unused engine, or an in-use engine that is newly rebuilt to its original configuration.

(b) Diesel test fuel. Federally required low sulfur diesel fuel (with a sulfur content of 0.05 weight percent) shall be used for all new emissions testing required to be performed for certification of retrofit/rebuild equipment for diesel-fueled urban bus engines.

(c) Test equipment selection. Certification shall be based upon tests utilizing representative production equipment selected in a random manner.

(d) Replacing original equipment parts. Installation of any certified retrofit/rebuild equipment shall not result in the permanent removal or rendering inoperative of any original equipment emission related part other than the part(s) being replaced. Furthermore, installation of any certified retrofit/rebuild equipment shall not cause or contribute to an unreasonable risk to the public health, welfare or safety, or result in any additional range of parameter adjustability or accessibility to adjustment than that of the vehicle manufacturer's emission related part.

(e) Affects on engine on-board diagnostic system. Installation of any certified retrofit/rebuild equipment shall not alter or render inoperative any feature of the on-board diagnostic system incorporated by the engine manufacturer. The certified equipment may integrate with the existing diagnostic system if it does not alter or render inoperative any features of the system.

(f) In-use enforcement.

(1) As a condition of certification, the equipment certifier agrees to notify operators who have installed this equipment and repair the equipment without cost to the operator when the Agency determines that a substantial number of the equipment kits, when properly maintained and used, and in actual use throughout the in-use compliance period, do not meet emission requirements.

(2) If the equipment certifier disagrees with such determination of nonconformity and so advises the Agency, the Administrator shall afford the equipment certifier and other interested persons an opportunity to present their views and evidence in support thereof at a public hearing conducted in accordance with procedures found in 40 CFR part 1068, subpart G.

[58 FR 21386, Apr. 21, 1993, as amended at 81 FR 73972, Oct. 25, 2016]