Document ID: chunk:federal_register_of_legislation:F2024L00443:reg:3:p6
Version: federal_register_of_legislation:F2024L00443
Segment Type: reg
Provision Reference: reg 3 (pt 6/13)
Character Range: 226112–228876

to 266 K (-7 °C)  2 K, prior to the low ambient temperature exhaust emission test. The ambient temperature (dry bulb) during this period shall average 266 K (-7 °C)  3 K, and shall not be less than 260 K (-13 °C) or more than 272 K (-1 °C).
               In addition, the temperature may not fall below 263 K (-10 °C) or exceed 269 K (-4 °C), for more than three consecutive minutes.
              4.3.4. If the vehicle is stabilised at 266 K (-7 °C), in a separate area and is moved through a warm area to the test cell, the vehicle shall be destabilised in the test cell for at least six times the period the vehicle is exposed to warmer temperatures. The ambient temperature (dry bulb) during this period shall average 266 K (-7 °C)  3 K and shall not be less than 260 K (-13 °C) nor more than 272 K (-1 °C).
               In addition, the temperature may not fall below 263 K (-10 °C) or exceed 269 K (-4 °C), for more than three consecutive minutes.
              5. Dynamometer procedure
              5.1.  Summary
              5.1.1. The emission sampling is performed over a test procedure consisting of the Part One cycle (Annex 4a to the 07 series of amendments to this Regulation, Table A4a/1 and Figure A4a/1). Engine start-up, immediate sampling, operation over the Part One cycle and engine shut-down make a complete low ambient temperature test, with a total test time of 780 seconds. The exhaust emissions are diluted with ambient air and a continuously proportional sample is collected for analysis. The exhaust gases collected in the bag are analysed for hydrocarbons, carbon monoxide, and carbon dioxide. A parallel sample of the dilution air is similarly analysed for carbon monoxide, total hydrocarbons and carbon dioxide.
              5.2. Dynamometer operation
              5.2.1.  Cooling fan
              5.2.1.1. A cooling fan is positioned so that cooling air is appropriately directed to the radiator (water cooling) or to the air intake (air-cooling) and to the vehicle.
              5.2.1.2. For front-engined vehicles, the fan shall be positioned in front of the vehicle, within 300 mm of it. In the case of rear-engined vehicles or if the above arrangement is impractical, the cooling fan shall be positioned so that sufficient air is supplied to cool the vehicle.
              5.2.1.3. The fan speed shall be such that, within the operating range of 10 km/h to at least 50 km/h, the linear velocity of the air at the blower outlet is within 5 km/h of the corresponding roller speed. The final selection of the blower shall have the following characteristics:
                  (a) Area: at least 0.2 m2;
                  (b) Height of the lower edge above ground: approximately 20 cm.
               As an alternative