(a) Emissions shall be measured using one of the test cycles specified in tables 1 through 4 of appendix B of this subpart, subject to the provisions of paragraphs (a)(1) through (a)(4) of this section. These cycles shall be used to test engines on a dynamometer.

(1) The 8-mode test cycle described in table 1 of appendix B of this subpart shall be used for all engines, except constant speed engines, engines rated under 19 kW, and propulsion marine diesel engines.

(2) The 5-mode test cycle described in table 2 of appendix B of this subpart shall be used for constant-speed engines as defined in §89.2. Any engine certified under this test cycle must meet the labeling requirements of §89.110(b)(11).

(3) The 6-mode test cycle described in table 3 of appendix B of this subpart shall be used for variable speed engines rated under 19 kW.

(4) Notwithstanding the provisions of paragraphs (a)(1) through (a)(3) of this section, the 4-mode test cycle described in table 4 of appendix B of this subpart shall be used for propulsion marine diesel engines.

(5) Notwithstanding the provisions of paragraphs (a)(1) through (a)(4) of this section:

(i) Manufacturers may use the 8-mode test cycle described in table 1 of appendix B of this subpart for:

(A) Constant speed engines, or variable speed engines rated under 19 kW; or

(B) Propulsion marine diesel engines, provided the propulsion marine diesel engines are certified in an engine family that includes primarily non-marine diesel engines, and the manufacturer obtains advance approval from the Administrator.

(ii) The Administrator may use the 8-mode test cycle specified in table 1 of appendix B of this subpart during testing of any engine which was certified based on emission data collected from that test cycle.

(b) During each non-idle mode, hold the specified load to within 2 percent of the engine maximum value and speed to within ±2 percent of point. During each idle mode, speed must be held within the manufacturer's specifications for the engine, and the throttle must be in the fully closed position and torque must not exceed 5 percent of the peak torque value of mode 5.

(c) For any mode except those involving either idle or full-load operation, if the operating conditions specified in paragraph (b) of this section cannot be maintained, the Administrator may authorize deviations from the specified load conditions. Such deviations shall not exceed 10 percent of the maximum torque at the test speed. The minimum deviations above and below the specified load necessary for stable operation shall be determined by the manufacturer and approved by the Administrator prior to the test run.

(d) Power generated during the idle mode may not be included in the calculation of emission results.

(e) Manufacturers may optionally use the ramped-modal duty cycles corresponding to the discrete-mode duty cycles specified in this section, as described in 40 CFR 1039.505.

[59 FR 31335, June 17, 1994. Redesignated and amended at 63 FR 56996, 57016, Oct. 23, 1998; 70 FR 40445, July 13, 2005]