Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:9:p4
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 9 (pt 4/71)
Character Range: 217303–220494

engine operating at the selected engine speed.

3.4.                            Cycle validation

              The relative standard deviations of the mean smoke values at each test speed (SVA, SVB, SVC, as calculated   in accordance with Section 6.3.3 of this Appendix from the three successive load steps at each test speed) shall be lower than 15 % of the mean value, or 10 % of the limit value shown in Table 1 of Annex I, whichever is greater. If the difference is greater, the sequence shall be repeated until three successive load steps meet the validation criteria.

         (1) The test points shall be selected using approved statistical methods of randomisation.

3.5.                            Rechecking of the opacimeter

              The post-test opacimeter zero drift value shall not exceed ± 5,0 % of the limit value shown in Table 1 of Annex I.

4.                                 CALCULATION OF THE GASEOUS EMISSIONS

4.1.                            Data evaluation

              For the evaluation of the gaseous emissions, the chart reading of the last 30 seconds of each mode shall be averaged, and the average concentrations (conc) of HC, CO and NOx during each mode shall be determined from the average chart readings and the corresponding calibration data. A different type of recording can be used if it ensures an equivalent data acquisition.

              For the NOx check within the control area, the above requirements apply for NOx, only.

              The exhaust gas flow GEXHW or the diluted exhaust gas flow GTOTW, if used optionally, shall be determined in accordance with Annex III, Appendix 4, Section 2.3.

4.2.                            Dry/wet correction

              The measured concentration shall be converted to a wet basis according to the following formulae, if not already measured on a wet basis.

              conc (wet) = Kw × conc (dry)

              For the raw exhaust gas:

              and,
              For the diluted exhaust gas:

              or,

              For the dilution air     For the intake air (if different from the dilution air)

              where:

              Ha, Hd = g water per kg dry air
              Rd, Ra = relative humidity of the dilution/intake air, %
              pd, pa  = saturation vapour pressure of the dilution/intake air, kPa pB  = total barometric pressure, kPa

4.3.                            NOx correction for humidity and temperature

              As the NOx emission depends on ambient air conditions, the NOx concentration shall be corrected for ambient air temperature and humidity with the factors given in the following formulae:

         with:

              A = 0,309 GFUEL/GAIRD - 0,0266

              B = - 0,209 GFUEL/GAIRD + 0,00954

              Ta = temperature of the air, K

              Ha = humidity of the intake air, g water per kg dry air
              in which

              Ra = relative humidity of the intake air, %

              pa = saturation vapour pressure of the intake air, kPa pB = total barometric pressure, kPa

4.4.                            Calculation of the emission mass flow rates

              The emission mass