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 Code of Federal Regulations (Last Updated: July 5, 2024)
 Title 40 - Protection of Environment
 Chapter I - Environmental Protection Agency
 SubChapter U - Air Pollution Controls
 Part 1039 - Control of Emissions from New and in-Use Nonroad Compression-Ignition Engines

  Appendix II to Part 1039 - Steady-State Duty Cycles  

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  • Appendix II to Part 1039 - Steady-State Duty Cycles

    (a) The following duty cycles apply for constant-speed engines:

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

    D2 mode number Engine speed Torque
    (percent)1     		Weighting
    factors
    1 Engine governed 100 0.05
    2 Engine governed 75 0.25
    3 Engine governed 50 0.30
    4 Engine governed 25 0.30
    5 Engine governed 10 0.10

    1 The percent torque is relative to maximum test torque.

    (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 53 Engine governed 100.
    1b Transition 20 Engine governed Linear transition.
    2a Steady-state 101 Engine governed 10.
    2b Transition 20 Engine governed Linear transition.
    3a Steady-state 277 Engine governed 75.
    3b Transition 20 Engine governed Linear transition.
    4a Steady-state 339 Engine governed 25.
    4b Transition 20 Engine governed Linear transition.
    5 Steady-state 350 Engine governed 50.

    1 The percent torque is relative to maximum test torque.

    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.

    (b) The following duty cycles apply for variable-speed engines with maximum engine power below 19 kW:

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

    G2 mode number Engine speed1 Torque
    (percent)2     		Weighting
    factors
    1 Maximum test speed 100 0.09
    2 Maximum test speed 75 0.20
    3 Maximum test speed 50 0.29
    4 Maximum test speed 25 0.30
    5 Maximum test speed 10 0.07
    6 Warm idle 0 0.05

    1 Speed terms are defined in 40 CFR part 1065.

    2 The percent torque is relative to the maximum torque at the commanded test speed.

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

    RMC mode Time in mode
    (seconds)     		Engine speed1 3 Torque
    (percent)2 3
    1a Steady-state 41 Warm idle 0.
    1b Transition 20 Linear transition Linear transition.
    2a Steady-state 135 Maximum test speed 100.
    2b Transition 20 Maximum test speed Linear transition.
    3a Steady-state 112 Maximum test speed 10.
    3b Transition 20 Maximum test speed Linear transition.
    4a Steady-state 337 Maximum test speed 75.
    4b Transition 20 Maximum test speed Linear transition.
    5a Steady-state 518 Maximum test speed 25.
    5b Transition 20 Maximum test speed Linear transition.
    6a Steady-state 494 Maximum test speed 50.
    6b Transition 20 Linear transition Linear transition.
    7 Steady-state 43 Warm idle 0.

    1 Speed terms are defined in 40 CFR part 1065.

    2 The percent torque is relative to the maximum torque at the commanded engine speed.

    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.

    (c) The following duty cycles apply for variable-speed engines with maximum engine power at or above 19 kW:

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

    C1 mode number Engine speed1 Torque
    (percent)2     		Weighting
    factors
    1 Maximum test speed 100 0.15
    2 Maximum test speed 75 0.15
    3 Maximum test speed 50 0.15
    4 Maximum test speed 10 0.10
    5 Intermediate test speed 100 0.10
    6 Intermediate test speed 75 0.10
    7 Intermediate test speed 50 0.10
    8 Warm idle 0 0.15

    1 Speed terms are defined in 40 CFR part 1065.

    2 The percent torque is relative to the maximum torque at the commanded test speed.

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

    RMC mode Time in mode
    (seconds)     		Engine speed1 3 Torque
    (percent)2 3
    1a Steady-state 126 Warm Idle 0.
    1b Transition 20 Linear Transition Linear Transition.
    2a Steady-state 159 Intermediate Speed 100.
    2b Transition 20 Intermediate Speed Linear Transition.
    3a Steady-state 160 Intermediate Speed 50.
    3b Transition 20 Intermediate Speed Linear Transition.
    4a Steady-state 162 Intermediate Speed 75.
    4b Transition 20 Linear Transition Linear Transition.
    5a Steady-state 246 Maximum Test Speed 100.
    5b Transition 20 Maximum Test Speed Linear Transition.
    6a Steady-state 164 Maximum Test Speed 10.
    6b Transition 20 Maximum Test Speed Linear Transition.
    7a Steady-state 248 Maximum Test Speed 75.
    7b Transition 20 Maximum Test Speed Linear Transition.
    8a Steady-state 247 Maximum Test Speed 50.
    8b Transition 20 Linear Transition Linear Transition.
    9 Steady-state 128 Warm Idle 0.

    1 Speed terms are defined in 40 CFR part 1065.

    2 The percent torque is relative to the maximum torque at the commanded engine speed.

    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.

    [69 FR 39213, June 29, 2004, as amended at 73 FR 37241, June 30, 2008]