Document ID: chunk:federal_register_of_legislation:F2008C00323:reg:120:p20
Version: federal_register_of_legislation:F2008C00323
Segment Type: reg
Provision Reference: reg 120 (pt 20/23)
Character Range: 291510–294579

of CO2 in the diluted exhaust gas contained in the sampling bag, expressed in per cent volume,

                   CHC = concentration of HC in the diluted exhaust gas contained in the sampling bag, expressed in ppm carbon equivalent,

                   CCO = concentration of CO in the diluted exhaust gas contained in the sampling bag, expressed in ppm.

         1.4.  DETERMINATION OF THE NO HUMIDITY CORRECTION FACTOR

         In order to correct the influence of humidity on the results of oxides of nitrogen, the following calculations are applied:

   kh =                        1
   1 – 0.0329     (H – 10.71)        (6)

         in which:

   H =                  6.211 . Ra . Pd
   PB - Pd . Ra . 10-2

         where:

               H  = absolute humidity expressed in grams of water per kilogram of dry air,

               Ra = relative humidity of the ambient air expressed as a percentage,

               Pd = saturation vapour pressure at ambient temperature expressed in kPa,

               PB = atmospheric pressure in the room, expressed in kPa.

         1.5. EXAMPLE

         1.5.1.  Data

         1.5.1.1. Ambient conditions:

         ambient temperature: 23 C = 297.2 K,

         barometric pressure: PB = 101.33 kPa,

         relative humidity: Ra = 60 per cent,

         saturation vapour pressure: Pd = 2.81 kPa of H2O at 23 C.

         1.5.1.2.  Volume measured and reduced to standard conditions (para. 1.)

         V = 51.961 m3

         1.5.1.3.  Analyser readings:

        Diluted exhaust sample  Dilution-air sample

HC (1)  92 ppm                  3.0 ppm

CO      470 ppm                 0 ppm

NOx     70 ppm                  0 ppm

CO2     1.6 per cent by volume  0.03 per cent by volume

         (1) in ppm carbon equivalent

         1.5.2.  Calculations

         1.5.2.1. Humidity correction factor (kH) (see formula 6):

   H =                  6.211 . Ra . Pd
   PB – Pd . Ra . 10-2

   H =                        6.211 . 60
   101.33 – (2.81 . 60.10-2)

   H =  10.5092

   kh =                      1
   1 – 0.0329 . (H – 10.71)

   kh =                            1
   1 – 0.0329 . (10.5092 – 10.71)

 kh = 0.9934

         1.5.2.2.                        Dilution factor (DF) (see formula (5))

   DF =                       13.4
   CC02 + (CHC + CC0) . 10-4

   DF =                      13.4
   1.6 + (92 + 4.70) . 10-4

 DF = 8.091

         1.5.2.3.                        Calculation of the corrected concentration of pollutants in the sampling bag:

         HC, mass emissions (see formulae (4) and (1))

   Ci  =  Ce – Cd (1–  1  )
   DF

   Ci     =  92 – 3 (1–  1  )
   8.091

 Ci      =     89.371

   MHC  =  CHC . Vmix . QHC .   1
   d

 QHC    =    0.619    in the case of petrol or diesel

 QHC    =    0.649    in the case of LPG

 QHC    =    0.714    in the case of NG

   MHC  =  89.371    .    51.961    .    0.619    .    10-6    .  1
   d

   MHC  =  2.88     g/km
   d

 CO, mass emissions (see formula (1))

   MCO  =  CCO    .    Vmix    .    QCO    .  1
   d