Document ID: chunk:federal_register_of_legislation:F2008C00323:reg:3:p3
Version: federal_register_of_legislation:F2008C00323
Segment Type: reg
Provision Reference: reg 3 (pt 3/18)
Character Range: 307930–311017

not be below 293 K (20 C), nor above 325 K (52 C) for the duration of the hot soak rest.

         To accommodate the volume changes due to enclosure temperature changes, either a variable-volume or fixed-volume enclosure may be used.

         4.2.1.  Variable-volume enclosure

         The variable-volume enclosure expands and contracts in response to the temperature change of the air mass in the enclosure. Two potential means of accommodating the internal volume changes are movable panel(s), or a bellows design, in which an impermeable bag or bags inside the enclosure expand(s) and contracts(s) in response to internal pressure changes by exchanging air from outside the enclosure. Any design for volume accommodation shall maintain the integrity of the enclosure as specified in Appendix 1 to this annex over the specified temperature range.

         Any method of volume accommodation shall limit the differential between the enclosure internal pressure and the barometric pressure to a maximum value of
         + 5 kPa.

         The enclosure shall be capable of latching to a fixed volume. A variable volume enclosure shall be capable of accommodating a +7 per cent change from its 'nominal volume' (see Appendix 1 to this Annex, paragraph 2.1.1.), taking into account temperature and barometric pressure variation during testing.

         4.2.2. Fixed-volume enclosure

         The fixed-volume enclosure shall be constructed with rigid panels that maintain a fixed enclosure volume, and meet the requirements below.

         4.2.2.1.  The enclosure shall be equipped with an outlet flow stream that withdraws air at a low, constant rate from the enclosure throughout the test. An inlet flow stream may provide make-up air to balance the outgoing flow with incoming ambient air. Inlet air shall be filtered with activated carbon to provide a relatively constant hydrocarbon level. Any method of volume accommodation shall maintain the differential between the enclosure internal pressure and the barometric pressure between 0 and –5 kPa.

         4.2.2.2. The equipment shall be capable of measuring the mass of hydrocarbon in the inlet and outlet flow streams with a resolution of 0.01 gram. A bag sampling system may be used to collect a proportional sample of the air withdrawn from and admitted to the enclosure. Alternatively, the inlet and outlet flow streams may be continuously analysed using an on-line FID analyser and integrated with the flow measurements to provide a continuous record of the mass hydrocarbon removal.

Figure 7/1
DETERMINATION OF EVAPORATIVE EMISSIONS
3000 km run-in period (no excessive purge/load)
Ageing of canister(s) verified
Steam-clean of vehicle (if necessary)
Notes:
     1.  Evaporative emission control families - details clarified.
     2.  Exhaust emissions may be measured during Type I test drive but these are not used for legislative purposes. Exhaust emission legislative test remains separate.

          4.3.  Analytical systems

          4.3.1.  Hydrocarbon analyser

          4.3.1.1.  The atmosphere within