86.335-79—Gasoline-fueled engine test cycle.
(a)
The following test sequence shall be followed in dynamometer operation tests of gasoline-fueled heavy-duty engines. Diesel engines are covered in § 86.336.
| Cycle No. | Mode No. | Mode | Observed torque (percent of maximum observed) | Time in mode-seconds | Cumulative time-seconds | Weighting factors |
|---|---|---|---|---|---|---|
| 1 | 1 | Idle | 60 | 60 | 0.232 | |
| 1 | 2 | Cruise | 25 | 60 | 120 | .077 |
| 1 | 3 | PTA | 55 | 60 | 180 | .147 |
| 1 | 4 | Cruise | 25 | 60 | 240 | .077 |
| 1 | 5 | PTD | 10 | 60 | 300 | .057 |
| 1 | 6 | Cruise | 25 | 60 | 360 | .077 |
| 1 | 7 | FL | 90 | 60 | 420 | .113 |
| 1 | 8 | Cruise | 25 | 60 | 480 | .077 |
| 1 | 9 | CT | 60 | 540 | .143 | |
| 2 | 10 | Cruise | 25 | 60 | 600 | .077 |
| 2 | 11 | PTA | 55 | 60 | 660 | .147 |
| 2 | 12 | Cruise | 25 | 60 | 720 | .077 |
| 2 | 13 | PTD | 10 | 60 | 780 | .057 |
| 2 | 14 | Cruise | 25 | 60 | 840 | .077 |
| 2 | 15 | FL | 90 | 60 | 900 | .113 |
| 2 | 16 | Cruise | 25 | 60 | 960 | .077 |
| 2 | 17 | CT | 60 | 1,020 | .143 | |
| 2 | 18 | Idle | 60 | 1,080 | .232 |
(b)
Except for idles, the engine dynamometer shall be operated at a constant speed of 2000 rpm±100 rpm. Speed deviations, not to exceed 200 rpm, will be allowed during the first 10 seconds of each mode.
(c)
The times in-mode specified in paragraph (a) for the CT modes are ±2 seconds. All other times in-mode are ±4 seconds.
(d)
The first 35 seconds of each 60 second engine power mode is allowed for engine-dynamometer stabilization. After this stabilization period the torque must be held at the specified value ±5 percent until the exhaust gas analysis period. During the exhaust gas analysis period, the last 10 seconds of each nonclosed throttle mode the engine torque must be at the specified value ±2 percent of the maximum torque observed. For example, mode 3 torque shall be held between 53 and 57 percent of maximum torque (55±2 percent) during the exhaust analysis period. Prior to the analysis period but excluding the first 35 seconds of the mode, the torque shall be held between 50 and 60 percent of maximum torque (55%±5%).
(e)
The idle operating mode shall be carried out at the manufacturer's recommended curb-idle engine speed. Arrive at the last idle mode by closing the throttle, braking the dynamometer to the engine idle speed, and unloading the dynamometer.
(f)
The CT operating mode shall be carried out at the same engine speed as specified in paragraph (b) of this section.
(g)
If the Administrator determines that an engine shall be tested as an automatic transmission code engine, then a load shall be applied by the dynamometer during the idle modes (1 and 18) such that the engine speed is decreased from the recommended dynamometer-idle speed to the recommended curb-idle speed. The engine idle torque recorded for the calculations in § 86.345 shall be zero.
(h)
If the operating conditions specified in paragraph (a) of this section for modes 2 through 8, and 10 through 16 cannot be maintained, the Administrator may authorize deviations from the specified load conditions. Such deviations shall not exceed 5 percent of the maximum torque at the test speed. The minimum deviations, above and below the specified load, necessary for stable operation shall be determined by the manufacturer and approved by the Administrator prior to the test run. Emission tests shall be performed by operating the engine at the higher approved load setting during cycle 1 and at the lower approved load setting during cycle 2. The weighting factors shall be as specified in paragraph (a) of this section.