Code of Federal Regulations > Title 40 > Chapter I > Part 1042 > Subpart J > Appendix Appendix II - Appendix II to Part 1042

Regulations last checked for updates: Jan 31, 2025

Title 40 - Protection of Environment last revised: Nov 08, 2025

Appendix Appendix II - Appendix II to Part 1042— Steady-State Duty Cycles

(a) The following duty cycles apply as specified in § 1042.505(b)(1):

(1) The following duty cycle applies for discrete-mode testing:

E3 mode No.	Engine speed ¹	Percent of maximum test power	Weighting factors
1	Maximum test speed	100	0.2
2	91%	75	0.5
3	80%	50	0.15
4	63%	25	0.15

¹ Maximum test speed is defined in 40 CFR part 1065. Percent speed values are relative to maximum test speed.

(2) The following duty cycle applies for ramped-modal testing:

RMC mode	Time in mode (seconds)	Engine speed ^{1 3}	Power (percent) ^{2 3}
1a Steady-state	229	Maximum test speed	100%.
1b Transition	20	Linear transition	Linear transition in torque.
2a Steady-state	166	63%	25%.
2b Transition	20	Linear transition	Linear transition in torque.
3a Steady-state	570	91%	75%.
3b Transition	20	Linear transition	Linear transition in torque.
4a Steady-state	175	80%	50%.

¹ Maximum test speed is defined in 40 CFR part 1065. Percent speed is relative to maximum test speed.

² The percent power is relative to the maximum test power.

³ Advance from one mode to the next within a 20 second transition phase. During the transition phase, command a linear progression from the torque setting of the current mode to the torque setting of the next mode, and simultaneously command a similar linear progression for engine speed if there is a change in speed setting.

(b) The following duty cycles apply as specified in § 1042.505(b)(2):

(1) The following duty cycle applies for discrete-mode testing:

E5 mode No.	Engine speed ¹	Percent of maximum test power	Weighting factors
1	Maximum test speed	100	0.08
2	91%	75	0.13
3	80%	50	0.17
4	63%	25	0.32
5	Warm idle	0	0.3

¹ Maximum test speed is defined in 40 CFR part 1065. Percent speed values are relative to maximum test speed.

(2) The following duty cycle applies for ramped-modal testing:

RMC mode	Time in mode (seconds)	Engine speed ^{1 3}	Power (percent) ^{2 3}
1a Steady-state	167	Warm idle	0.
1b Transition	20	Linear transition	Linear transition in torque.
2a Steady-state	85	Maximum test speed	100%.
2b Transition	20	Linear transition	Linear transition in torque.
3a Steady-state	354	63%	25%.
3b Transition	20	Linear transition	Linear transition in torque.
4a Steady-state	141	91%	75%.
4b Transition	20	Linear transition	Linear transition in torque.
5a Steady-state	182	80%	50%.
5b Transition	20	Linear transition	Linear transition in torque.
6 Steady-state	171	Warm idle	0.

¹ Maximum test speed is defined in 40 CFR part 1065. Percent speed is relative to maximum test speed.

² The percent power is relative to the maximum test power.

(1) The following duty cycle applies for discrete-mode testing:

E2 mode No.	Engine speed ¹	Torque (percent) ²	Weighting factors
1	Engine Governed	100	0.2
2	Engine Governed	75	0.5
3	Engine Governed	50	0.15
4	Engine Governed	25	0.15

¹ Speed terms are defined in 40 CFR part 1065.

² The percent torque is relative to the maximum test torque as defined in 40 CFR part 1065.

(2) The following duty cycle applies for ramped-modal testing:

RMC mode	Time in mode (seconds)	Engine speed	Torque (percent) ^{1 2}
1a Steady-state	229	Engine Governed	100%.
1b Transition	20	Engine Governed	Linear transition.
2a Steady-state	166	Engine Governed	25%.
2b Transition	20	Engine Governed	Linear transition.
3a Steady-state	570	Engine Governed	75%.
3b Transition	20	Engine Governed	Linear transition.
4a Steady-state	175	Engine Governed	50%.

¹ The percent torque is relative to the maximum test torque as defined in 40 CFR part 1065.

² Advance from one mode to the next within a 20 second transition phase. During the transition phase, command a linear progression from the torque setting of the current mode to the torque setting of the next mode.

[81 FR 74156, Oct. 25, 2016]

authority: 42 U.S.C. 7401-7671q.

source: 73 FR 37243, June 30, 2008, unless otherwise noted.