Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:12:p1
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 12 (pt 1/5)
Character Range: 1886318–1889581

12                                                        23                                                                                     20.2          23           3.4
                                                                                                                                                               24           35.6

              6.5.9.2. The enclosure shall be purged for several minutes immediately before the test until a stable background is obtained. The chamber mixing fan(s) shall also be switched on at this time.

              6.5.9.3. The test vehicle, with the powertrain shut off and the test vehicle windows and luggage compartment(s) opened, shall be moved into the measuring chamber. The mixing fan(s) shall be adjusted in such a way as to maintain a minimum air circulation speed of 8 km/h under the fuel tank of the test vehicle.

              6.5.9.4. The hydrocarbon analyser shall be zeroed and spanned immediately before the test.

              6.5.9.5. The enclosure doors shall be closed and sealed gas-tight.

              6.5.9.6. Within 10 minutes of closing and sealing the doors, the hydrocarbon concentration, temperature and barometric pressure shall be measured to give initial readings of hydrocarbon concentration in the enclosure (CHCi), barometric pressure (Pi) and ambient chamber temperature (Ti) for the diurnal testing. Tstart = 0 starts at this time.

              6.5.9.7. The hydrocarbon analyser shall be zeroed and spanned immediately before the end of each emission sampling period.

              6.5.9.8. The end of the first and second emission sampling period shall occur at 24 hours 6 minutes and 48 hours 6 minutes, respectively, after the beginning of the initial sampling, as specified in paragraph 6.5.9.6. of this annex. The elapsed time shall be recorded.
              At the end of each emission sampling period, the hydrocarbon concentration, temperature and barometric pressure shall be measured and used to calculate the diurnal test results using the equation in paragraph 7.1. of this annex. The result obtained from the first 24 hours shall be recorded as MD1. The result obtained from the second 24 hours shall be recorded as MD2.
              6.6. Continuous test procedure for sealed fuel tank systems

              6.6.1. In the case that the fuel tank relief pressure is greater than or equal to 30 kPa

              6.6.1.1. The test shall be performed as described in paragraphs 6.5.1. to 6.5.3. inclusive of this annex.

              6.6.1.2. Fuel drain and refill
              Within one hour after the preconditioning drive, the fuel tank of the vehicle shall be emptied. This shall be done so as not to abnormally purge or abnormally load the evaporative control devices fitted to the vehicle. Removal of the fuel cap is normally sufficient to achieve this, otherwise the carbon canister shall be disconnected. The fuel tank shall be refilled with reference fuel at a temperature of 18 °C ±2 °C to 15 ±2 per cent of the tank's nominal capacity. The operations described in paragraphs 6.6.1.3., 6.6.1.4. and 6.6.1.5. of this annex shall be completed within a total of 36 hours and for the operations described in paragraphs 6.6.1.4. and