40 CFR § 94.105 - Duty cycles.

§ 94.105 Duty cycles.

(a) Overview. For the purpose of determining compliance with the emission standards of § 94.8, except for those in § 94.8(e), engines shall be tested using the appropriate duty cycles described in this section.

(b) General cycle. Propulsion engines that are used with (or intended to be used with) fixed-pitch propellers, propeller-law auxiliary engines, and any other engines for which the other duty cycles of this section do not apply, shall be tested using the duty cycle described in the following Table B-1:

Table B-1 - General Marine Duty Cycle

Mode No. Engine speed 1 (percent of maximum test speed) Percent of maximum test power 2 Minimum time in mode
(minutes)
Weighting factors
1 100 100 5.0 0.20
2 91 75 5.0 0.50
3 80 50 5.0 0.15
4 63 25 5.0 0.15

1 Engine speed: ±2 percent of point.

2 Power: ±2 percent of engine maximum value.

(c) Variable-pitch and electrically coupled propellers.

(1) Constant-speed propulsion engines that are used with (or intended to be used with) variable-pitch propellers or with electrically coupled propellers shall be tested using the duty cycle described in the following Table B-2:

Table B-2 - Duty Cycle for Constant-Speed Propulsion Engines

Mode No. Engine speed 1 (percent of maximum test speed) Percent of maximum test power 2 Minimum time in mode
(minutes)
Weighting factors
1 100 100 5.0 0.20
2 100 75 5.0 0.50
3 100 50 5.0 0.15
4 100 25 5.0 0.15

1 Engine speed: ±2 percent of point.

2 Power: ±2 percent of engine maximum value.

(2) For the purpose of determining compliance with the emission standards of § 94.8, variable-speed propulsion engines that are used with (or intended to be used with) variable-pitch propellers or with electrically coupled propellers shall be tested using the duty cycle described in Table B-3, which follows:

Table B-3 - Duty Cycle for Variable Speed Propulsion Engines Used on Non-Propeller Law Vessels and for Variable Speed Auxiliary Engines

Test segment Mode No. Engine speed 1 Percent of maximum test torque 2 Minimum time in mode
(minutes)
Weighting factors
1 1 Maximum Test Speed 100 5.0 0.15
1 2 Maximum Test Speed 75 5.0 0.15
1 3 Maximum Test Speed 50 5.0 0.15
1 4 Maximum Test Speed 10 5.0 0.10
2 5 Intermediate 100 5.0 0.10
2 6 Intermediate 75 5.0 0.10
2 7 Intermediate 50 5.0 0.10
2 8 Idle 0 5.0 0.15

1 Engine speed (non-idle): ±2 percent of point. Engine speed (idle): Within manufacturer's specifications. Idle speed is specified by the manufacturer.

2 Torque (non-idle): ±2 percent of engine maximum value. Torque (idle): minimum fueling rate Load less than 5 percent of peak torque.

(d) Auxiliary. For the purpose of determining compliance with the emission standards of § 94.8:

(1) Constant speed auxiliary engines shall be tested using the duty cycle described in Table B-4, which follows:

Table B-4 - Duty Cycle for Constant-Speed Auxiliary Engines

Mode No. Engine speed 1 Percent of maximum test torque 2 Minimum time in mode
(minutes)
Weighting factors
1 Maximum Test Speed 100 5.0 0.05
2 Maximum Test Speed 75 5.0 0.25
3 Maximum Test Speed 50 5.0 0.30
4 Maximum Test Speed 25 5.0 0.30
5 Maximum Test Speed 10 5.0 0.10

1 Engine speed: ±2 percent of point.

2 Torque: ±2 percent of engine maximum value.

(2) Variable speed auxiliary engines shall be tested using the duty cycle described in Table B-3 in paragraph (c)(2) of this section.

(e) Recreational. For the purpose of determining compliance with the emission standards of § 94.8, recreational engines shall be tested using the duty cycle described in Table B-5, which follows:

Table B-5 - Recreational Marine Duty Cycle

Mode No. Engine speed (1) (percent of maximum test speed) Percent of maximum test power (2) Minimum time in mode (minutes) Weighting factors
1 100 100 5.0 0.08
2 91 75 5.0 0.13
3 80 50 5.0 0.17
4 63 25 5.0 0.32
5 idle 0 5.0 0.30

1 Engine speed: ±2 percent of point.

2 Power: ±2 percent of engine maximum value.

[64 FR 73331, Dec. 29, 1999, as amended at 67 FR 68343, Nov. 8, 2002; 70 FR 40458, July 13, 2005]