This section describes how to test engines under steady-state conditions. In some cases, we allow you to choose the appropriate steady-state duty cycle for an engine; you may also choose between discrete-mode and ramped-modal testing. In all cases, you must use the duty cycle you select in your application for certification for all testing you perform for that engine family. If we test your engines to confirm that they meet emission standards, we will use the duty cycles you select for your own testing. If you submit certification test data using more than one duty cycle, any of the selected duty cycles may be used for any subsequent testing. We may also perform other testing as allowed by the Clean Air Act.
Table 1 of § 1048.505
C2 mode No. | Engine speed1 | Torque (percent)2 | Weighting factors |
1 | Maximum test speed | 25 | 0.06 |
2 | Intermediate test | 100 | 0.02 |
3 | Intermediate test | 75 | 0.05 |
4 | Intermediate test | 50 | 0.32 |
5 | Intermediate test | 25 | 0.30 |
6 | Intermediate test | 10 | 0.10 |
7 | 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 given engine speed.
Table 2 of § 1048.505
RMC mode | Time in mode (seconds) | Engine speed1 2 | Torque (percent)2 3 |
1a Steady-state | 119 | Warm idle | 0 |
1b Transition | 20 | Linear transition | Linear transition. |
2a Steady-state | 29 | Intermediate speed | 100 |
2b Transition | 20 | Intermediate speed | Linear transition. |
3a Steady-state | 150 | Intermediate speed | 10 |
3b Transition | 20 | Intermediate speed | Linear transition. |
4a Steady-state | 80 | Intermediate speed | 75 |
4b Transition | 20 | Intermediate speed | Linear transition. |
5a Steady-state | 513 | Intermediate speed | 25 |
5b Transition | 20 | Intermediate speed | Linear transition. |
6a Steady-state | 549 | Intermediate speed | 50 |
6b Transition | 20 | Linear transition | Linear transition. |
7a Steady-state | 96 | Maximum test speed | 25 |
7b Transition | 20 | Linear transition | Linear transition. |
8 Steady-state | 124 | Warm idle | 0 |
1 Speed terms are 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.
3 The percent torque is relative to maximum torque at the commanded engine speed.
Table 3 of § 1048.505
Mode No. | Engine speed | Torque (percent)1 | Minimum time in mode (minutes) | Weighting factors |
1 | Maximum test speed | 100 | 3.0 | 0.50 |
2 | Maximum test speed | 75 | 3.0 | 0.50 |
1 The percent torque is relative to the maximum torque at maximum test speed.
Table 4 of § 1048.505
RMC modes | Time in mode (seconds) | Engine speed (percent) | Torque (percent)1 2 |
1a Steady-state | 290 | Engine governed | 100 |
1b Transition | 20 | Engine governed | Linear transition. |
2 Steady-state | 290 | Engine governed | 75 |
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.
40 C.F.R. §1048.505