Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:13:p51
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 13 (pt 51/56)
Character Range: 433450–436174

guess for QSSV or Cd of the calibration venturi, and repeated until QSSV converges. The convergence method shall be accurate to 0.1 per cent of point or better.
 For a minimum of sixteen points in the region of subsonic flow, the calculated values of Cd from the resulting calibration curve fit equation shall be within ±0.5 per cent of the measured Cd for each calibration point.
              9.5.5. Total system verification

The total accuracy of the CVS sampling system and analytical system shall be determined by introducing a known mass of a pollutant gas into the system while it is being operated in the normal manner. The pollutant is analysed, and the mass calculated according to paragraph 8.5.2.3. except in the case of propane where a u factor of 0.000507 is used in place of 0.000483 for HC. Either of the following two techniques shall be used.
9.5.5.1. Metering with a critical flow orifice
 A known quantity of pure gas (carbon monoxide or propane) shall be fed into the CVS system through a calibrated critical orifice. If the inlet pressure is high enough, the flow rate, which is adjusted by means of the critical flow orifice, is independent of the orifice outlet pressure (critical flow). The CVS system shall be operated as in a normal exhaust emission test for about 5 to 10 minutes. A gas sample shall be analyzed with the usual equipment (sampling bag or integrating method), and the mass of the gas calculated.
 The mass so determined shall be within ±3 per cent of the known mass of the gas injected.
9.5.5.2. Metering by means of a gravimetric technique
 The mass of a small cylinder filled with carbon monoxide or propane shall be determined with a precision of ±0.01 g. For about 5 to 10 minutes, the CVS system shall be operated as in a normal exhaust emission test, while carbon monoxide or propane is injected into the system. The quantity of pure gas discharged shall be determined by means of differential weighing. A gas sample shall be analyzed with the usual equipment (sampling bag or integrating method), and the mass of the gas calculated.
 The mass so determined shall be within ±3 per cent of the known mass of the gas injected.
10. Particle number measurement test procedure
              10.1. Sampling
              Particle number emissions shall be measured by continuous sampling from either a partial flow dilution system, as described in Appendix 2 to this annex, paragraph A.2.2.1. and A.2.2.2. or a full flow dilution system as described in Appendix 2 to this annex, paragraph A.2.2.3. and A.2.2.4.
              10.1.1. Diluent filtration
               Diluent used for both the primary and, where applicable, secondary dilution of the exhaust in the dilution system