Document ID: chunk:federal_register_of_legislation:F2008C00323:reg:3:p8
Version: federal_register_of_legislation:F2008C00323
Segment Type: reg
Provision Reference: reg 3 (pt 8/18)
Character Range: 321144–323867

The chamber air mixing fan(s) shall be switched on at this time.

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

          5.1.5. Canister loading with repeated heat builds to breakthrough

          5.1.5.1.  The fuel tank(s) of the vehicle(s) is (are) emptied using the fuel tank drain(s). 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.

          5.1.5.2.  The fuel tank(s) is (are) refilled with test fuel at a temperature of between 283 K to 287 K (10 to 14 C) to 40 + 2 per cent of the tank's normal volumetric capacity. The fuel cap(s) of the vehicle shall be fitted at this point.

          5.1.5.3. Within one hour of being refuelled the vehicle shall be placed, with the engine shut off, in the evaporative emission enclosure. The fuel tank temperature sensor is connected to the temperature recording system. A heat source shall be properly positioned with respect to the fuel tank(s) and connected to the temperature controller. The heat source is specified in paragraph 4.4. above. In the case of vehicles fitted with more than one fuel tank, all the tanks shall be heated in the same way as described below. The temperatures of the tanks shall be identical to within  1.5 K.

          5.1.5.4. The fuel may be artificially heated to the starting diurnal temperature of 293 K (20C)  1 K.

          5.1.5.5.  When the fuel temperature reaches at least 292 K (19 C), the following steps shall be taken immediately: the purge blower shall be turned off; enclosure doors closed and sealed; and measurement initiated of the hydrocarbon level in the enclosure.

          5.1.5.6.  When the fuel temperature of the fuel tank reaches 293 K (20 C) a linear heat build of 15 K (15 C) begins. The fuel shall be heated in such a way that the temperature of the fuel during the heating conforms to the function below to within  1.5 K. The elapsed time of the heat build and temperature rise is recorded.

         Tr = To + 0.2333 . t

         where:

         Tr = required temperature (K);

         To = initial temperature (K);

         t  = time from start of the tank heat build in minutes.

          5.1.5.7. As soon as break-through occurs or when the fuel temperature reaches 308 K (35C), whichever occurs first, the heat source is turned off, the enclosure doors unsealed and opened, and the vehicle fuel tank cap(s) removed. If break-through has not occurred by the time the fuel temperature 308 K (35 C), the heat source is removed from the vehicle, the vehicle removed from the evaporative emission enclosure