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Code of Federal Regulations Title 40. Protection of Environment 40 CFR Pt. 1039, App. II—Steady–State Duty Cycles

Current as of January 02, 2025 | Updated by Findlaw Staff

(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 speed 1

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 speed 1, 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 speed 1

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 speed 1, 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.

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Cite this article: FindLaw.com - Code of Federal Regulations Title 40. Protection of Environment 40 CFR Pt. 1039, App. II—Steady–State Duty Cycles - last updated January 02, 2025 | https://codes.findlaw.com/cfr/title-40-protection-of-environment/cfr-pt-40-1039-app-ii/

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