Document ID: chunk:federal_register_of_legislation:F2023C00229:reg:10:p8
Version: federal_register_of_legislation:F2023C00229
Segment Type: reg
Provision Reference: reg 10 (pt 8/30)
Character Range: 542251–545273

the diluted exhaust gas flow. The flow rate of the diluted exhaust (qmdew) shall be measured over each mode with a PDP-CVS, CFV-CVS or SSV-CVS in line with the general formulae given in section 4.1 of Appendix 2 to this Annex. The accuracy shall be ± 2 % of reading or better, and shall be determined according to the provisions of section 2.4 of Appendix 5 to this Annex.'

       (iv)   Sections 4 and 5 are replaced by the following:

       '5. CALCULATION OF THE GASEOUS EMISSIONS

        5.1.  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 corre- sponding 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 qmew or the diluted exhaust gas flow qmdew, if used optionally, shall be determined in accordance with sec- tion 2.3 of Appendix 4 to this Annex.

        5.2.  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. The conversion shall be done for each individual mode.

              For the raw exhaust gas:

              or

              where:

pr  =  water vapour pressure after cooling bath, kPa,
pb  =  total atmospheric pressure, kPa,
Ha  =  intake air humidity, g water per kg dry air,
kf  =  0,055584 × wALF – 0,0001083 × wBET – 0,0001562 × wGAM + 0,0079936 × wDEL + 0,0069978 × wEPS

              For the diluted exhaust gas:

              or,

         For the dilution air:

         For the intake air:

         where:

Ha  =  intake air humidity, g water per kg dry air
Hd  =  dilution air humidity, g water per kg dry air

              and may be derived from relative humidity measurement, dewpoint measurement, vapour pressure measurement or dry/wet bulb measurement using the generally accepted formulae.

        5.3.  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. The factors are valid in the range between 0 and 25 g/kg dry air.

              (a) for compression ignition engines:

              with:

              Ta = temperature of the intake air, K

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

              where:

              Ha may be derived from relative humidity measurement, dewpoint measurement, vapour pressure measurement or dry/wet bulb measurement using the generally accepted formulae.

              (b) for spark ignition engines

              where: