Document ID: chunk:federal_register_of_legislation:F2012C00283:reg:20:p17
Version: federal_register_of_legislation:F2012C00283
Segment Type: reg
Provision Reference: reg 20 (pt 17/19)
Character Range: 240375–243842

applied:

           (6)

          in which:

 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.

              6.6.6. Determination of HC for compression-ignition engines
               To calculate HC-mass emission for compression-ignition engines, the average HC concentration is calculated as follows:

           (7)

               where:
                = integral of the recording of the heated FID over the test    (t2-t1)
               Ce  = concentration of HC measured in the diluted exhaust in   ppm of Ci is substituted for CHC in all relevant equations.
              6.6.7. Determination of particulates
               Particulate emission Mp (g/km) is calculated by means of the following equation:

               Where exhaust gases are vented outside tunnel;

 Where exhaust gases are returned to the tunnel;
 Where:
 Vmix                                             =  volume of diluted exhaust gases (see paragraph 6.6.1.), under standard conditions,
 Vep                                              =  volume of exhaust gas flowing through particulate filter under standard conditions,
 Pe                                               =  particulate mass collected by filter(s),
 d                                                =  distance corresponding to the operating cycle in km,
 Mp                                               =  particulate emission in g/km.

               Where correction for the particulate background level from the dilution system has been used, this shall be determined in accordance with paragraph 6.2.4. In this case, the particulate mass (g/km) shall be calculated as follows:

                Where exhaust gases are vented outside tunnel;

                Where exhaust gases are returned to the tunnel.
 Where:
 Vap     =  volume of tunnel air flowing through the background particulate filter under standard conditions,
 Pa      =  particulate mass collected by background filter,
 DF      =  dilution factor as determined in paragraph 6.6.4.

               Where application of a background correction results in a negative particulate mass (in g/km) the result shall be considered to be zero g/km particulate mass.
              6.6.8. Determination of particle numbers
               Number emission of particles shall be calculated by means of the following equation:

 Where:
 N       =  particle number emission expressed in particles per kilometre,
 V       =  volume of the diluted exhaust gas expressed in litres per test and corrected to standard conditions (273.2 K and 101.33 kPa),
 K       =  calibration factor to correct the particle number counter measurements to the level of the reference instrument where this is not applied internally within the particle number counter. Where the calibration factor is applied internally within the particle number counter a value of 1 shall be used for k in the above equation,
         =  corrected concentration of particles from the diluted exhaust gas expressed as the average particles per cubic centimetre figure from the emissions test including the full duration of the drive cycle. If the volumetric mean concentration results () from the particle number counter are