Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:9:p36
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 9 (pt 36/37)
Character Range: 1878009–1880865

this operation meets the requirement described in Annex B6 or Annex B8.
              6.5.7. Hot soak evaporative emissions test
              Within 7 minutes after the dynamometer test and within 2 minutes of the engine being switched off, the hot soak evaporative emissions test shall be performed in accordance with paragraphs 6.5.7.1. to 6.5.7.8. of this annex. The hot soak losses shall be calculated according to paragraph 7.1. of this annex and recorded as MHS.
              6.5.7.1. Before the completion of the test run the measuring chamber shall be purged for several minutes until a stable hydrocarbon background is obtained. The enclosure mixing fan(s) shall also be turned on at this time.
              6.5.7.2. The hydrocarbon analyser shall be zeroed and spanned immediately prior to the test.
              6.5.7.3. At the end of the driving cycle the engine bonnet shall be completely closed and all connections between the vehicle and the test stand disconnected. The vehicle is then driven to the measuring chamber with a minimum use of the accelerator pedal. The engine shall be turned off before any part of the vehicle enters the measuring chamber. The time at which the engine is switched off is recorded on the evaporative emission measurement data recording system and temperature recording begins. The vehicle's windows and luggage compartments shall be opened at this stage, if not already opened.
              6.5.7.4. The vehicle shall be pushed or otherwise moved into the measuring chamber with the engine switched off.
              6.5.7.5. The enclosure doors are closed and sealed gas-tight within two minutes of the engine being switched off and within seven minutes of the end of the conditioning drive.
              6.5.7.6. The start of a 60  0.5 minute hot soak period begins when the chamber is sealed. The hydrocarbon concentration, temperature and barometric pressure are measured to give the initial readings CHCi, Pi and Ti for the hot soak test. These figures are used in the evaporative emission calculation, paragraph 6. The ambient temperature T of the enclosure shall not be less than 23 °C and no more than 31 °C during the 60-minute hot soak period.
              6.5.7.7. The hydrocarbon analyser shall be zeroed and spanned immediately before the end of the 60  0.5 minute test period.
              6.5.7.8. At the end of the 60  0.5 minute test period, the hydrocarbon concentration in the chamber shall be measured. The temperature and the barometric pressure are also measured. These are the final readings CHCf, Pf and Tf for the hot soak test used for the calculation in paragraph 6. of this annex.
              6.5.8. Soak
              After the hot soak evaporative emissions test, the test vehicle shall be soaked for not less than 6 hours and not more than 36 hours between the end