Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:23:p1
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 23 (pt 1/15)
Character Range: 1899091–1902336

23              20.2

              6.7. Stand-alone test procedure for sealed fuel tank systems

              6.7.1 Measurement of depressurisation puff loss loading mass

              6.7.1.1. The procedures in paragraphs 6.6.1.1. to 6.6.1.7.2. inclusive of this annex shall be performed. The depressurisation puff loss loading mass is defined as the difference in weight of the vehicle carbon canister before paragraph 6.6.1.6. of this annex is applied and after paragraph 6.6.1.7.2. of this annex is applied.
              6.7.1.2. The depressurisation puff loss overflow from the vehicle carbon canister shall be measured according to paragraphs 6.6.1.8.1. and 6.6.1.8.2. inclusive of this Annex and fulfil the requirements of paragraph 6.6.1.8.3. in this annex.

              6.7.2. Hot soak and diurnal breathing evaporative emissions test

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

              6.7.2.1.1. The test shall be performed as described in paragraphs 6.5.1. to 6.5.3. and 6.6.1.9. to 6.6.1.9.1. inclusive of this annex.

              6.7.2.1.2. The carbon canister shall be aged according to the sequence described in paragraph 5.1. to 5.1.3.1.3. inclusive of this annex and shall be loaded and purged according to paragraph 6.6.1.5. of this annex.
              6.7.2.1.3. The aged carbon canister shall subsequently be loaded according to the procedure described in paragraph 6.5.5.4. However, instead of loading to breakthrough as described in paragraph 6.5.5.4.4., the total loading mass shall be determined in accordance with paragraph 6.7.1.1. of this annex. At the request of the manufacturer, the reference fuel may alternatively be used instead of butane. The carbon canister shall be disconnected.
              6.7.2.1.4. The procedures in paragraphs 6.6.1.10. to 6.6.1.13. inclusive of this annex shall be followed.

              6.7.2.2. In the case that the fuel tank relief pressure is lower than 30 kPa

              The test shall be performed as described in paragraphs 6.7.2.1.1. to 6.7.2.1.4. inclusive of this annex. However, in this case, the ambient temperature described in paragraph 6.5.9.1. of this annex shall be modified in accordance with the profile specified in Table A1/1 of this annex for the diurnal emission test.
              7. Calculation of evaporative test results
              7.1. The evaporative emission tests described in paragraphs 6. to 6.7.2.2. inclusive of this annex allow the hydrocarbon emissions from the puff loss overflow, diurnal and hot soak tests to be calculated. Evaporative losses from each of these tests shall be calculated using the initial and final hydrocarbon concentrations, temperatures and pressures in the enclosure, together with the net enclosure volume.
              The following equation shall be used:

              MHC

              where:

                  MHC  is the mass of hydrocarbons, grams;

                  MHC,out is the mass of hydrocarbons exiting the enclosure in the case of fixed volume enclosures for diurnal emission testing, grams;

                  MHC,in  is the mass of hydrocarbon entering the enclosure in the case of fixed volume enclosures for