Engines using SCR to control emissions depend on a constant supply of diesel exhaust fluid (DEF). This section describes how manufacturers must design their engines to derate power output to induce operators to take appropriate actions to ensure the SCR system is working properly. The requirements of this section apply equally for engines installed in heavy-duty vehicles at or below 14,000 lbs GVWR. The requirements of this section apply starting in model year 2027, though you may comply with the requirements of this section in earlier model years.
Table 1 to Paragraph (a)(2) of § 1036.111 -Vehicle Categories
Vehicle categorya | Average speed (mi/hr) |
Low-speed | speed [LESS THAN]15. |
Medium-speed | 15 [LESS THAN EQUAL TO] speed [LESS THAN]25. |
High-speed | speed [GREATER THAN EQUAL TO]25. |
a A vehicle is presumed to be a high-speed vehicle if it has not yet logged 30 hours of non-idle operation.
Table 2 to Paragraph (d)(1) of § 1036.111 -Derate Schedule for Detected Inducement Triggering Conditions a
High-speed vehicles | Medium-speed vehicles | Low-speed vehicles | |||
Hours of non-idle engine operation | Maximum speed (mi/hr) | Hours of non-idle engine operation | Maximum speed (mi/hr) | Hours of non-idle engine operation | Maximum speed (mi/hr) |
0 | 65 | 0 | 55 | 0 | 45 |
6 | 60 | 6 | 50 | 5 | 40 |
12 | 55 | 12 | 45 | 10 | 35 |
20 | 50 | 45 | 40 | 30 | 25 |
86 | 45 | 70 | 35 | ||
119 | 40 | 90 | 25 | ||
144 | 35 | ||||
164 | 25 |
a Hours start counting when the engine detects an inducement triggering condition specified in paragraph (b) of this section. For DEF supply, you may program the engine to reset the timer to three hours when the engine detects an empty DEF tank.
40 C.F.R. §1036.111