1048.505—How do I test engines using steady-state duty cycles, including ramped-modal testing?
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. In these 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. We may also perform other testing as allowed by the Clean Air Act.
(a)
You may perform steady-state testing with either discrete-mode or ramped-modal cycles, as follows:
(1)
For discrete-mode testing, sample emissions separately for each mode, then calculate an average emission level for the whole cycle using the weighting factors specified for each mode. Calculate cycle statistics and compare with the established criteria as specified in 40 CFR 1065.514 to confirm that the test is valid. Operate the engine and sampling system as follows:
(i)
Engines with lean NO
X
aftertreatment. For lean-burn engines that depend on aftertreatment to meet the NOX emission standard, operate the engine for 5-6 minutes, then sample emissions for 1-3 minutes in each mode.
(ii)
Engines without lean NO
X
aftertreatment. For other engines, operate the engine for at least 5 minutes, then sample emissions for at least 1 minute in each mode.
(2)
For ramped-modal testing, start sampling at the beginning of the first mode and continue sampling until the end of the last mode. Calculate emissions and cycle statistics the same as for transient testing as specified in 40 CFR part 1065, subpart G.
(b)
Measure emissions by testing the engine on a dynamometer with one or more of the following sets of duty cycles to determine whether it meets the steady-state emission standards in § 1048.101(b) :
(1)
For engines from an engine family that will be used only in variable-speed applications, use one of the following duty cycles:
| C2 mode No. | Engine speed 1 | Torque(percent) 2 | Weightingfactors |
|---|---|---|---|
| 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. | |||
| RMC mode | Time in mode(seconds) | Engine speed 1,2 | 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. | |||
(2)
For engines from an engine family that will be used only at a single, rated speed, use the 5-mode duty cycle or the corresponding ramped-modal cycle described in 40 CFR part 1039, Appendix II, paragraph (a).
(3)
Use a duty cycle from both paragraphs (b)(1) and (b)(2) of this section if you will not restrict an engine family to constant-speed or variable-speed applications.
| Mode No. | Enginespeed | 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. | ||||
| 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. | |||
(c)
If we test an engine to confirm that it meets the duty-cycle emission standards, we will use the steady-state duty cycles that apply for that engine family.
(g)
For those cases where steady-state testing does not directly follow a transient test, perform the steady-state test according to this section after an appropriate warm-up period, consistent with 40 CFR part 1065, subpart F.