Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p31
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 31/108)
Character Range: 971891–975055

shall lie on the radial centre line of each sector (22.5°) at two-thirds of the outlet radius (as shown in Figure A5/2).
Figure A5/2
Fan with circular outlet
              These measurements shall be made with no vehicle or other obstruction in front of the fan. The device used to measure the linear velocity of the air shall be located between 0 and 20 cm from the air outlet.
              1.1.3. The outlet of the fan shall have the following characteristics:
              (a) An area of at least 0.3 m2; and
              (b) A width/diameter of at least 0.8 metre.
              1.1.4. The position of the fan shall be as follows:
              (a) Height of the lower edge above ground: approximately 20 cm;
              (b) Distance from the front of the vehicle: approximately 30 cm;
              (c)  Approximately on the longitudinal centreline of the vehicle.
              1.1.5. At the request of the manufacturer and if considered appropriate by the responsible authority, the height, lateral position and distance from the vehicle of the cooling fan may be modified.
              If the specified fan configuration is impractical for special vehicle designs, such as vehicles with rear-mounted engines or side air intakes, or it does not provide adequate cooling to properly represent in-use operation, at the request of the manufacturer and if considered appropriate by the responsible authority, the height, capacity, longitudinal and lateral position of the cooling fan may be modified and additional fans which may have different specifications (including constant speed fans) may be used.
              1.1.6. In the cases described in paragraph 1.1.5. of this annex, the position and capacity of the cooling fan(s) and details of the justification supplied to the responsible authority shall be recorded. For any subsequent testing, similar positions and specifications shall be used in consideration of the justification to avoid non-representative cooling characteristics.
              2. Chassis dynamometer
              2.1. General requirements
              2.1.1. The dynamometer shall be capable of simulating road load with three road load coefficients that can be adjusted to shape the load curve.
              2.1.2. The chassis dynamometer may have a single or twin-roller configuration. In the case that twin-roller chassis dynamometers are used, the rollers shall be permanently coupled or the front roller shall drive, directly or indirectly, any inertial masses and the power absorption device.
              2.2. Specific requirements
              The following specific requirements relate to the dynamometer manufacturer's specifications.
              2.2.1. The roller run-out shall be less than 0.25 mm at all measured locations.
              2.2.2. The roller diameter shall be within ±1.0 mm of the specified nominal value at all measurement locations.
              2.2.3. The dynamometer shall have a time measurement system for use in determining acceleration rates and for measuring vehicle/dynamometer coastdown times. This time measurement system shall not exceed an accuracy of ±0.001 per cent after at